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Haidar, Mochamad Ali. "Hubungan Antara Konsentrasi Toluena Dengan Konsentrasi Malondialdehida Dan Degenerasi DNA Pada Pekerja Home Industry Sepatu". Preventif : Jurnal Kesehatan Masyarakat 14, n. 1 (30 aprile 2023): 67–81. http://dx.doi.org/10.22487/preventif.v14i1.460.
Testo completoAbstract (sommario):
ABSTRAK Toluena adalah pelarut organik yang terkandung didalam lem perekat sepatu di home industry sepatu Tambak Osowilangun Surabaya. Toluena bersifat volatile sehingga mudah terhirup. Toluena dimetabolisme menjadi toluena epoksida yang dapat meningkatkan spesies oksigen reaktif yang mengakibatkan peroksidasi lipid ditandai dengan malondialdehida dan juga menyebabkan degenerasi DNA.Tujuan penelitian ini untuk melihat hubungan antara konsentrasi toluena dengan konsentrasi malondialdehida dan degenerasi DNA pada pekerja home industry Sepatu Tambak Osowilangun Surabaya. Penelitian ini merupakan penelitian observasional analitik dengan desain penelitian cross sectional dengan teknik total population sampling yaitu sebanyak 25 pekerja. Variabel bebas pada penelitian ini adalah konsentrasi toluena. Variabel terikat adalah konsentrasi malondialdehida dan degenerasi DNA. Hasil penelitian menunjukkan bahwa rata-rata konsentrasi toluena melebihi NAB. Rata-rata konsentrasi malondialdehida pekerja sebesar 7,84 nmol/ml. Terdapat hubungan yang lemah antara konsentrasi toluena dengan konsentrasi malondialdehida (0,201) dan degenerasi DNA (0,312). Dapat disimpulkan bahwa konsentrasi toluena melebihi NAB secara terus menerus dapat meningkatkan konsentrasi malondialdehida dan degenerasi DNA. Disarankan kepada pekerja menggunakan alat bantu untuk mengoleskan lem, mengonsumsi makanan yang kaya enzim sitokrom oksidase dan glutathione, menggunakan alat pelindung diri seperti respirator cartridge kimia selama bekerja. Kata kunci: degenerasi DNA, malondialdehida, toluena, sepatu ABSTRACT Toluene is an organic solvent contained in the shoe adhesive glue at the shoes home-industry Tambak Osowilangun Surabaya. Toluene is volatile so it is easily inhaled. Toluene is metabolized into toluene epoxide which can increase reactive oxygen species resulting in lipid peroxidation characterized by malondialdehyde and also causes DNA degeneration. This research is an analytic observational study with a cross sectional research design with a total population sampling technique of 25 workers. The independent variable in this study was toluene concentration. The dependent variable is the malondialdehyde concentration and DNA degeneration. The results showed that the average concentration of toluene exceeded the TLV. The workers' average of malondialdehyde concentration was 7,84 nmol/ml. There is a weak relationship between the concentration of toluene with the concentration of malondialdehyde (0,201) and DNA degeneration (0,312). It can be concluded that the concentration of toluene exceeding the TLV continuously can increase the malondialdehyde concentration and DNA degeneration. It is recommended that workers use tools to apply glue, eat foods rich in cytochrome oxidase and glutathione enzymes, use personal protective equipment such as chemical cartridge respirators while working. Keywords: DNA degeneration, malondialdehyde, shoes, toluene
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Irmasari, Fardani. "Level of Airbone Toluene in Work Environment is Associated With Level of Urine Hippuric Acid in Printing Workers at Rungkut Surabaya". JURNAL KESEHATAN LINGKUNGAN 10, n. 3 (4 dicembre 2018): 328. http://dx.doi.org/10.20473/jkl.v10i3.2018.328-335.
Testo completoAbstract (sommario):
One of industrial hazards in printing can come from chemical elements. The chemicals that may be in the printing industry is toluene. Toluene used in 75% of printing work activity. The biggest toluen used as automatic cleaning. Other toluen used as a printing ink, solvent, varnish and glue. The purpose of this study was to analyze the relationship between airbone toluene levels with hippuric acid in workers Printing in Rungkut Surabaya. This research was an observational analytic, used cross sectional design. The sample of this study were 30 people, taken by random sampling. The results of pearson correlation test showed that there were a association between airbone toluene with hippuric acid in urine (p= 0.000; r=0.796) and results of pearson correlation test showed thatthere is no association between airbone toluene with eye irritation complaint (p=0.268). Its conclued that level of airbone toluene in work environment is associated with level of urine hippuric acid in printing workers at Rungkut Surabaya. Suggestions from this research is the company must conduct periodic monitoring in the airbone workplace of workers and to raise workers awareness of the importance of PPE.
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Suhartono, S., Herri Susanto, Dwiwahju Sasongko e Azis Trianto. "Pengukuran konstanta henry toluen dan benzen dalam minyak dan air dengan kolom gelembung". Jurnal Teknik Kimia Indonesia 9, n. 2 (2 ottobre 2018): 49. http://dx.doi.org/10.5614/jtki.2010.9.2.2.
Testo completoAbstract (sommario):
Determination of Henry’s constant for toluene and benzene in oils and water were carried out in a bubbling bottle with diameter of 3 cm. Air containing toluene vapour or benzene vapour was bubbled through 50 mL absorbing liquid. The gas flow rate was 13.6 mL/min. By measuring the concentration of toluene or benzene in the inlet and outlet gas stream, we were able to calculate their concentrations in absorbing liquid. We found that the value of Henry’s constant of toluene in lubrication oil and palm oil at 30 oC were 155 and 145 respectively (H= CG/CL, with CG in mol/L and CL in mol/L). We also found that the absorption capacities were in the order (from the highest) of: lubrication oil, palm oil, and sunflower oil. Henry’s constant of toluene in water was at about 4 which was much lower than those of oils.Keyword: absorption, Henry’s constant, toluene, benzene, producer gas AbstrakPengukuran konstanta Henry sistem toluen dan benzen dalam minyak dan air dilakukan melalui percobaan absorpsi di dalam sebuah kolom gelembung dengan diameter 3 cm. Minyak sawit, minyak bunga matahari, minyak pelumas dan air digunakan sebagai absorben. Toluen dan benzen dipilih sebagai tar model. Gas model yang tersusun dari udara dan uap toluen atau benzen digelembungkan ke dalam absorben 50 mL. Absorpsi dilakukan pada suhu 30 dan 60 oC dan laju alir gas model 13,6 mL/min. Analisa dilakukan terhadap konsentrasi aliran gas model sebelum dan sesudah absorpsi. Analisa tersebut dilakukan dengan kromatografi gas Shimadzu GC-8APF. Konstanta Henry dihitung sebagai H=CG/CL dan H=P/CL. Nilai 1/H sistem toluen-minyak pelumas dan toluen-minyak sawit pada suhu 30 oC dan laju alir gas 13,6 mL/min berturut-turut adalah 155 dan 145 (untuk CG dalam mol/L dan CL dalam mol/L). Merujuk pada nilai-nilai konstanta Henry hasil percobaan, minyak pelumas dan minyak sawit merupakan cairan penyerap yang paling cocok untuk toluen dan benzen sebagai representasi tar dalam gas hasil gasifikasi. Urutan besarnya kapasitas absorpsi cairan penyerap terhadap toluen dan benzen adalah sebagai berikut (berturut-turut dari yang besar): minyak pelumas, minyak sawit, minyak bunga matahari dan air. Konstanta Henry toluen dalam air berada pada kisaran 4, yang menunjukkan bahwa kapasitas absorpsi toluen dalam air lebih rendah dibandingkan kapasitas absorpsi toluen dalam minyak.Kata Kunci: absorpsi, konstanta Henry, toluen, benzen, gas produser
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Agustriyanto, Rudy, Puguh Setyopratomo, Endang Srihari Mochni e Edy Purwanto. "Simulation of the Hydrodealkylation of Toluene Using Conversion Reactor". Keluwih: Jurnal Sains dan Teknologi 5, n. 1 (29 maggio 2024): 19–26. http://dx.doi.org/10.24123/saintek.v5i1.6351.
Testo completoAbstract (sommario):
Abstract—The hydrodealkylation of toluene is frequently used to produce the more valuable compound benzene. This process is widely employed in the petrochemical industry. Through hydrodealkylation, toluene undergoes a transformation, resulting in the production of valuable chemicals such as benzene and diphenyl. The objective of this study is to present the results obtained from simulating the process of toluene dealkylation using Aspen HYSYS. The feed to the reactor must contain toluene and hydrogen, while the recommended operating conditions are at 500 oC to 650 oC and 20 to 40 atm pressure to achieve 90% conversion. For this purpose, a conversion reactor has been selected as the preferred type. The simulation outcomes are particularly valuable during the initial stages of designing a production facility for benzene. The mass and energy balance calculations can be easily performed using Aspen HYSYS. Future research may focus on investigating different reactor types while considering the kinetics of the reaction. Keywords: aspen HYSYS, hydrodealkylation, simulation, toluene Abstrak—Hidrodealkilasi toluena sering digunakan untuk menghasilkan senyawa yang lebih bernilai yaitu benzene. Proses ini banyak digunakan dalam industri petrokimia. Melalui hidrodealkilasi, toluena mengalami transformasi, menghasilkan bahan kimia berharga seperti benzene dan diphenyl. Tujuan dari penelitian ini adalah untuk menyajikan hasil yang diperoleh dari mensimulasikan proses dealkilasi toluena menggunakan Aspen HYSYS. Umpan ke reaktor harus mengandung toluena dan hidrogen, sedangkan kondisi operasi yang direkomendasikan adalah pada suhu 500 oC hingga 650 oC dan tekanan 20 hingga 40 atm untuk mencapai konversi 90%. Untuk tujuan ini, reaktor konversi telah dipilih sebagai tipe yang disukai. Hasil simulasi sangat berharga selama tahap awal perancangan fasilitas produksi benzene. Perhitungan neraca massa dan energi dapat dengan mudah dilakukan menggunakan Aspen HYSYS. Penelitian masa depan dapat fokus pada penyelidikan berbagai jenis reaktor sambil mempertimbangkan kinetika reaksi. Kata kunci: aspen HYSYS, hidrodealkilasi, simulasi, toluene
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Bukasa, Dewi A., Harry S. J. Koleangan e Audy D. Wuntu. "ADSORPSI TOLUENA PADA ARANG AKTIF TEMPURUNG KEMIRI". JURNAL ILMIAH SAINS 12, n. 2 (31 ottobre 2012): 93. http://dx.doi.org/10.35799/jis.12.2.2012.561.
Testo completoAbstract (sommario):
ADSORPSI TOLUENA PADA ARANG AKTIF TEMPURUNG KEMIRI ABSTRAK Telah diteliti adsorpsi toluena pada arang aktif yang dibuat dari tempurung kemiri yang diaktivasi dengan ZnCl2. Penelitian ini bertujuan untuk menentukan parameter adsorpsi, yaitu kapasitas dan energi adsorpsi. Parameter tersebut dihitung dari persamaan regresi linear yang diperoleh dari data adsorpsi toluena pada arang aktif dalam sistem tertutup yang dianalisis menggunakan model isoterm adsorpsi Dubinin-Raduskevich. Hasil yang diperoleh menunjukkan bahwa arang aktif tempurung kemiri dapat mengadsorpsi toluena dengan kapasitas adsorpsi sebesar 0,094 cm3/g dan nilai energi adsorpsi, yaitu 2,56 kJ/mol. Selain itu dilakukan pula penentuan waktu setimbang adsorpsi arang aktif tempurung kemiri terhadap toluena dengan berbagai variasi waktu. Hasilnya menunjukkan arang aktif tempurung kemiri mencapai keadaan setimbang terhadap toluena pada waktu 5 jam. Kata kunci: Adsorpsi, Karbon Aktif, Tempurung Kemiri TOLUENE ADSORPTION ON CANDLENUT SHELL ACTIVATED CARBON ABSTRACT The adsorption of toluene on activated charcoal prepared from candlenut (Aleurites moluccana) shell activated with ZnCl2 was investigated. This investigation was aimed to calculate the adsorption parameters which were adsorption capacity and energy of toluene on the adorbent. The parameters were calculated using linear regression equation derived from data of acetone adsorption on the activated carbon in a closed system and were analyzed using Dubinin-Raduskevich adsorption isotherm model. The results obtained indicated that the candlenut shell activated charcoal had adsorption capacity value of 0.094 cm3/g and the adsorption energy values of 2.56 kJ / mol. Besides, the time required to reach equilibrium state for the adsorption of toluene on the adsorbat was conducted. The results showed that the adsorption state was obtained in 5 hours. Keywords: Adsorption , Activated Carbon, Candlenut Shell
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Wuntu, Audy D., e Vanda S. Kamu. "KINETICS OF GASEOUS TOLUENE ADSORPTION ON CANDLENUT SHELL ACTIVATED CARBON". JURNAL ILMIAH SAINS 13, n. 1 (2 giugno 2013): 33. http://dx.doi.org/10.35799/jis.13.1.2013.1979.
Testo completoAbstract (sommario):
KINETICS OF GASEOUS TOLUENE ADSORPTION ON CANDLENUT SHELL ACTIVATED CARBON ABSTRACT Adsorption kinetics of gaseous toluene on activated carbon prepared from candlenut shell had been studied. The research was performed by examining adsorption data, which was obtained in previous research, over several rate equations, which were: (1) Lagergren’s pseudo first order rate equation, (2) Ho’s pseudo second order rate equation, (3) Elovich’s equation, and (4) persamaan Ritchie’s equation. The result showed that the data of toluene adsorption on candlenut shell activated carbon fits the Ho’s pseudo second order rate equation and, hence, the model is the most applicable model for the adsorption. Calculation from linear regression of Ho’s pseudo second order rate equation gave the equilibrium adsorption capacity value of 56,069 mg g-1, second order rate constant of 3,54x10–4 g mg-1 min-1, and initial adsorption rate of 1,112 mg g-1 min-1. Keywords: adsorption, candlenut, activated carbon, toluene KINETIKA ADSORPSI GAS TOLUENA PADA KARON AKTIF TEMPURUNG KEMIRI ABSTRAK Studi mengenai aspek kinetika adsorpsi toluena pada arang aktif yang terbuat dari tempurung kemiri telah dilakukan. Penelitian dilakukan dengan menguji data adsorpsi yang telah diperoleh pada penelitian terdahulu menggunakan empat persamaan laju adsorpsi, yaitu (1) persamaan laju pseudo order pertama Lagergren, (2) persamaan laju pseudo order kedua Ho, (3) persamaan Elovich, dan (4) persamaan Ritchie. Hasil kajian menunjukkan bahwa model kinetika dengan persamaan laju pseudo order kedua Ho adalah yang paling sesuai diaplikasikan untuk adsorpsi gas toluena pada arang aktif tempurung kemiri. Dari persamaan linear untuk model kinetika pseudo order kedua Ho diperoleh nilai kapasitas adsorpsi pada kesetimbangan sebesar 56,069 mg g-1, konstanta adsorpsi sebesar 3,54x10–4 g mg-1 menit-1, dan laju adsorpsi awal sebesar 1,112 mg g-1 menit-1. Kata kunci: adsorpsi, kemiri, karbon aktif, toluena
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Schwantes, Rebecca H., Katherine A. Schilling, Renee C. McVay, Hanna Lignell, Matthew M. Coggon, Xuan Zhang, Paul O. Wennberg e John H. Seinfeld. "Formation of highly oxygenated low-volatility products from cresol oxidation". Atmospheric Chemistry and Physics 17, n. 5 (10 marzo 2017): 3453–74. http://dx.doi.org/10.5194/acp-17-3453-2017.
Testo completoAbstract (sommario):
Abstract. Hydroxyl radical (OH) oxidation of toluene produces ring-retaining products: cresol and benzaldehyde, and ring-opening products: bicyclic intermediate compounds and epoxides. Here, first- and later-generation OH oxidation products from cresol and benzaldehyde are identified in laboratory chamber experiments. For benzaldehyde, first-generation ring-retaining products are identified, but later-generation products are not detected. For cresol, low-volatility (saturation mass concentration, C* ∼ 3.5 × 104 − 7.7 × 10−3 µg m−3), first- and later-generation ring-retaining products are identified. Subsequent OH addition to the aromatic ring of o-cresol leads to compounds such as hydroxy, dihydroxy, and trihydroxy methyl benzoquinones and dihydroxy, trihydroxy, tetrahydroxy, and pentahydroxy toluenes. These products are detected in the gas phase by chemical ionization mass spectrometry (CIMS) and in the particle phase using offline direct analysis in real-time mass spectrometry (DART-MS). Our data suggest that the yield of trihydroxy toluene from dihydroxy toluene is substantial. While an exact yield cannot be reported as authentic standards are unavailable, we find that a yield for trihydroxy toluene from dihydroxy toluene of ∼ 0.7 (equal to the reported yield of dihydroxy toluene from o-cresol; Olariu et al., 2002) is consistent with experimental results for o-cresol oxidation under low-NO conditions. These results suggest that even though the cresol pathway accounts for only ∼ 20 % of the oxidation products of toluene, it is the source of a significant fraction (∼ 20–40 %) of toluene secondary organic aerosol (SOA) due to the formation of low-volatility products.
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Hendriyana, H., S. Suhartono e Herri Susanto. "Thermodynamic study on vapour-liquid equilibrium of toluene and several types of oil as absorbent". Jurnal Teknik Kimia Indonesia 10, n. 1 (2 ottobre 2018): 18. http://dx.doi.org/10.5614/jtki.2011.10.1.3.
Testo completoAbstract (sommario):
Thermodynamic study on vapour-liquid equilibrium of toluene and several types of oil as absorbent Gas cleaning system is one of important step in the utilization of biomass via gasification process. The producer gas obtained from the gasification process must be very clean before it is used in an internal combustion engine. In order to gaseous fuel get cleaned with a tar content below 100 mg/Nm3, a gas cleaning system using scrubbing oil is being developed and taking the advantage of a lower vapour pressure of oil than scrubbing water. Study on vapour-liquid equilibrium is being conducted to understand the phenomena taking place in the absorption of tar with oil. In our present study, the producer gas containing tar is represented using air containing toluene. This producer gas model with a toluene or benzene concentration then bubbled with a rate of 27.6 mL/min into a bath of oil at a various temperature. The progress of absorption of tar model in oil measured gas chromatography until saturated condition. Considering that the concentration of toluene in the gas stream is very low, the toluene and oil vapour-liquid equilibrium follows the Henry’s law. Prediction of Henry’s constants is also carried out using UNIFAC-FV model which is known to be suitable for hydrocarbon gases and high-boiling point hydrocarbon solvent. Keywords: tar, oil, Henry’s constant AbstrakSistem pembersihan gas merupakan salah satu langkah penting dalam pemanfaatan biomassa melalui proses gasifikasi. Gas produser yang dihasilkan dari proses gasifikasi harus sangat bersih sebelum digunakan dalam mesin pembakaran internal. Untuk mendapatkan bahan bakar gas yang bersih dengan kandungan tar di bawah 100 mg/Nm3. Sebuah sistem pembersihan gas dengan menggunakan minyak sebagai media penyerap dikembangkan dengan mengambil keuntungan dari tekanan uap minyak lebih rendah air penyerap. Studi kesetimbangan uap-cair yang dilakukan untuk memahami fenomena yang terjadi dalam penyerapan tar dengan minyak. Dalam kami studi ini, gas produser yang mengandung direpresentasikan dengan udara yang mengandung toluena. Model gas produser ini dibuat dengan menggelembungkan konsentrasi benzena atau toluena dengan laju 27,6 mL/menit ke dalam bak minyak pada berbagai suhu. Kemajuan penyerapan model tar dalam minyak diukur dengan cromathograpy gas sampai dengan kondisi jenuh. Mengingat konsentrasi toluena dalam aliran gas sangat rendah, maka kesetimbangan uap-cair toluena dan minyak mengikuti hukum Henry. Konstanta Henry juga dapat diprediksi dengan menggunakan model UNIFAC-FV yang cocok untuk gas hidrokarbon dan pelarut hidrokarbon dengan titik didih tinggi. Kata kunci: tar, minyak, konstanta Henry
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Wyndham, R. C. "Adaptation of estuarine bacteria to toluene at low concentrations in sea water: cometabolism of toluene". Canadian Journal of Microbiology 31, n. 10 (1 ottobre 1985): 910–18. http://dx.doi.org/10.1139/m85-171.
Testo completoAbstract (sommario):
The ability of sediment-water interface bacteria to adapt to micromolar concentrations of water-dissolved toluene was determined. Control and experimental chambers of 200 cm2 of undisturbed sediment were fitted for continuous replacement of overlying seawater. The experimental chamber received toluene in sterile seawater at a rate determined to give concentrations of 4 to 17 μM during adaptation. Samples of seawater and sediment surface were removed at intervals and analyzed for bacterial numbers and rates of assimilation of radiolabeled glutamate, phenol, and toluene. Adaptation occurred in 3 to 5 days in the experimental chamber and was characterized by rapid increases in phenol and toluene assimilation. An increase in phenol assimilation by sediment surface bacteria was the first detectable adaptation. Kinetic analyses indicated bacteria in seawater overlying the sediments had a greater affinity for toluene (half-saturation at 50 nM) following adaptation than for phenol (half-saturation at 3.9 μM). The first-order rate constant for toluene assimilation at low concentrations decreased 10-fold on prolonged continuous culture of the seawater community at millimolar concentrations of toluene. Total numbers of bacteria by direct count and plate count, and bacterial activity measured with [14C]glutamate, did not change appreciably in the control and experimental chambers. During the early stages of adaptation the meta-ring-fission product of 3-methylcatechol accumulated in the seawater to a concentration of 4.9 μM. Tests of isolates from plate counts on phenol and toluene vapours revealed 30% formed diffusable yellow metabolites of these substrates in the absence of significant growth. One of these isolates showed partial metabolism of toluene and meta-toluate to the first metabolite following meta-ring fission, 2-hydroxy-6-keto-2,4-heptadienoate, by resting cells and cells growing on alternative carbon sources.
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Panggabean, Aman Sentosa, Tika Widyastuti e Noor Hindryawati. "Validasi Metode Penentuan Benzena, Toluena dan Xilena pada Sampel Udara dan Tanah Menggunakan Kromatografi Gas". ALCHEMY Jurnal Penelitian Kimia 15, n. 1 (1 marzo 2019): 177. http://dx.doi.org/10.20961/alchemy.15.1.25522.177-189.
Testo completoAbstract (sommario):
<p>Penelitian tentang validasi metode penentuan kadar benzena, toluena dan xilena pada sampel udara dan tanah dengan menggunakan kromatografi gas telah dilakukan. Untuk mendapatkan hasil pengukuran yang valid, beberapa parameter penting yang berpengaruh dalam validasi metode telah ditentukan. Beberapa parameter penting yang dilakukan adalah penentuan besaran dasar kromatografi yang meliputi: waktu retensi, kapasitas (k’), faktor selektivitas (α) dan kinerja analitik yang meliputi: penentuan linearitas (r), limit deteksi (LOD), limit kuantitasi (LOQ), presisi dan akurasi. Hasil penelitian penentuan kinerja analitik sangat baik ditunjukkan oleh nilai presisi sebagai % KV < 2/3 nilai KV Horwitz, LOD untuk masing-masing senyawa benzena, toluena dan xilena adalah 0,02 mg/L; 0,59 mg/L dan 0,08 mg/L serta LOQ untuk masing-masing senyawa benzena, toluena dan xilena adalah 0,07 mg/L; 1,99 mg/L dan 0,27 mg/L. Akurasi metode ini sangat baik ditunjukkan dengan nilai presentase perolehan kembali masing-masing senyawa benzena, toluena dan xilena untuk sampel tanah sebesar 102,61 ± 4,61%; 101,65 ± 7,41%; 102,15 ± 4,15%, dan untuk sampel udara masing-masing senyawa sebesar 101,69 ± 5,77%; 102,08 ± 5,43% dan 98,55 ± 5,11%. Berdasarkan hasil penelitian ini, metode kromatografi gas dapat digunakan dalam penentuan benzena, toluena dan xilena pada sampel udara dan tanah dengan memberikan hasil yang valid.</p><p><strong>Validation Method </strong><strong>o</strong><strong>n The Determination </strong><strong>o</strong><strong>f Benzene, Toluene </strong><strong>a</strong><strong>nd Xylene </strong><strong>i</strong><strong>n Air </strong><strong>a</strong><strong>nd Soil Samples Using Gas Chromatography. </strong>The present study investigated the method for the determination of the content of benzene, toluene, and xylene in air and soil samples using gas chromatography. To obtain a valid measurement result, several important parameters that influence the method validation have been determined. The several important parameters carried out are the determination of the basic chromatographic such as retention time, capacity factor (k'), selectivity (α) and analytical performance measurement includes: the determination of linearity (r), limit of detection (LOD), limit of quantitation (LOQ), precision and accuracy. The result of analytical performance of the research are well verified, in which the value of precision was % CV < 2/3 CV Horwitz value, LOD for benzene, toluene, and xylene compound were 0.02 mg/L, 0.59 mg/L, 0.08 mg/L, respectively, and LOQ for benzene, toluene and xylene compounds was 0.07 mg/L, 1.99 mg/L and 0.27 mg/L respectively. This method achieved high accuration, indicated by a percentage of recovery value of benzene, toluene, and xylene for soil samples of 102.61 ± 4.61%; 101.65 ± 7.41%; 102.15 ± 4.15%, and for air samples was 101.69 ± 5.77%, 102.08 ± 5.43%, and 98.55 ± 5.11% respectively. Based on the results of this research, the method presented in this study can be applied for the determination of benzene, toluene, and xylene using gas chromatography in air and soil samples with valid results.</p>
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Craik, DJ, RM Drew, I. Kyratzis, ID Rae e JA Weigold. "Relaxation Processes in Aromatic Methyl-Groups. I. 2-Chloro-Toluene and 2,6-Dichloro-Toluene". Australian Journal of Chemistry 39, n. 12 (1986): 2049. http://dx.doi.org/10.1071/ch9862049.
Testo completoAbstract (sommario):
Three series of selectively deuterated toluenes, 2-chlorotoluenes and 2,6-dichlorotoluenes have been synthesized, and their methyl group 1H n.m.r. relaxation pathways have been determined by 1H, 2H and 13C n.m.r. spin-lattice relaxation time measurements. 1H spin-lattice relaxation in the methyl groups of these series occurs predominantly through an intramethyl H-H dipolar mechanism as well as through the spin-rotation mechanism. Dipolar spin-lattice relaxation rates for intramethyl H-H pairs are 0.012, 0.020 and 0.025 s-1 for toluene, 2,6-dichlorotoluene and 2-chlorotoluene respectively, suggesting a decrease in the rate of methyl group rotation in this order. Ab initio molecular orbital calculations on the same compounds show that the theoretically predicted barrier to methyl group rotation increases in the order toluene < 2,6-dichlorotoluene < 2-chlorotoluene, supporting the experimentally derived results.
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Laelasari, Eva, Dewi Kristanti e Basuki Rahmat. "PENGGUNAAN LEM SEPATU DAN GANGGUAN KESEHATAN PEKERJA INDUSTRI SEPATU DI CIOMAS, BOGOR". JURNAL EKOLOGI KESEHATAN 17, n. 2 (16 ottobre 2018): 85–95. http://dx.doi.org/10.22435/jek.17.2.150.85-95.
Testo completoAbstract (sommario):
ABSTRACT
The use of glue in shoe manufactures may cause health impacts among workers due to hazardous chemical exposure in glue such as benzene and toluene. The government has issued policies to prevent the workers from occupational illness by reducing the hazardous chemical exposure in the workplace. This study was conducted to find out health impacts due to benzenae and toluene exposure from the use of glue in the workplace of shoe manufactures in Ciomas, Bogor in 2017. Design of the study was cross sectional with variables of benzene and toluene content in indoor workspace, consentration of urinary S-PMA, and perceived health symptoms of workers. Samples of 34 respondents were obtained from 5 selected workshop. Analysis of the data was carried out descriptively. It was found that the content of benzene and toluene in glue are 0.1% and 55% respectively, indoor benzene vapor was below detection limit of the instrument (undetected), and concentration of urinary S-PMA was 0.24 µg/g creatinine. There was no benzene exposure to the workers in this study. High percentage of worker risk behavior were smoking, the use of PPE, and hand washing. Perceived symptoms of workers (more than 60%) were fatigue, headache, tingling. It is necessary to improve workplace with healthier and more conducive environment, and educate workers to use the PPE.
Keywords: Shoe glue, benzene, toluene, exposure, small scale shoe manufacture
ABSTRAK
Penggunaan lem pada industri sepatu kemungkinan memberikan dampak kesehatan terhadap pekerja karena lem biasanya mengandung bahan berbahaya, seperti benzena dan toluena. Pemerintah sudah berupaya membuat kebijakan untuk mengendalikan penyakit akibat kerja, salah satunya adalah mengurangi pajanan bahan kimia berbahaya. Penelitian ini bertujuan untuk mengetahui dampak kesehatan akibat pajanan benzena dan toluena yang berasal dari penggunaan lem di tempat kerja di sentra industri sepatu Ciomas, Bogor pada tahun 2017. Desain penelitian adalah potong lintang dengan variabel kandungan benzena dan toluena di udara ruang kerja, kandungan S-PMA dalam urin, dan gangguan kesehatan yang dialami oleh pekerja. Jumlah sampel pekerja sebanyak 34 orang yang berasal dari 5 bengkel kerja. Analisis data dilakukan secara deskriptif. Hasil penelitian menunjukkan bahwa kadar benzena dan toluena dalam lem masing-masing adalah 0,1% dan 55%, kadar uap benzena di udara ruang kerja berada di bawah limit deteksi alat (tidak terdeteksi), dan rerata kandungan S-PMA dalam urin adalah 0,24 µg/g kreatinin. Tidak terjadi pajanan benzena terhadap pekerja industri sepatu di lokasi penelitian. Perilaku berisiko pekerja dengan persentase cukup tinggi adalah merokok, penggunaan APD, dan cuci tangan. Keluhan/gangguan kesehatan yang dirasakan (lebih dari 60%) adalah cepat lelah, sakit kepala, kesemutan. Perlu perbaikan lingkungan kerja yang lebih sehat dan nyaman, dan mengedukasi pekerja untuk menggunakan APD.
Kata kunci: Lem sepatu, benzena, toluena, pajanan, industri sepatu rumahan
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Pramitasari, Deviana, e S. Subagjo. "Pengembangan katalis Ni/Al2o3 untuk steam reforming tar hasil gasifikasi". Jurnal Teknik Kimia Indonesia 10, n. 2 (2 ottobre 2018): 43. http://dx.doi.org/10.5614/jtki.2011.10.2.1.
Testo completoAbstract (sommario):
The development of catalysts Ni/Al2O3 for steam reforming gasification tar This research studied the secondary tar removal in gasification technology through catalytic toluene steam reforming reactions. The objective of this study was to obtain a nickel catalyst that has good performance for steam reforming of tar (toluene) by selecting the -Al2O3 or -Al2O3 supports, and adding promoter to inhibit deactivation due to coke formation. The performance of the catalyst is determined from the activity test in a fixed bed reactor at a temperature of 700 oC, atmospheric pressure, Time on Stream (TOS) 10 hours and stability test indicated by XRD and TGA. The catalyst showed the best performance was the Ni/-Al2O3 catalyst with the average of toluene conversion of 96%. The addition of 2% and 5% by weight of CaO decreased the catalytic activity. Although it proved to inhibit the formation of coke, it did not reduce the rate of deactivation of catalyst. The XRD analysis showed that the Ni/-Al2O3 after 10 hours in operation did not undergo any phase changes, thus the catalyst was still stable. Keywords: tar cracking, steam reforming, nickel catalyst, toluene conversion, stability. AbstrakPenelitian ini merupakan suatu bagian dalam pengembangan teknologi penghilangan tar gasifikasi secara sekunder dengan cara perengkahan katalitik menggunakan reaksi steam reforming toluen. Tujuan penelitian ini adalah mendapatkan katalis berbasis nikel yang memiliki kinerja yang baik untuk steam reforming tar (toluen) dengan memilih penyangga -Al2O3 atau -Al2O3, dan menambah promotor CaO untuk menghambat deaktivasi akibat pembentukan arang. Kinerja katalis ditentukan dari uji aktivitas di dalam reaktor fixed bed pada temperatur 700 oC, tekanan atmosferik, selama 10 jam dan uji stabilitas yang diindikasikan menggunakan XRD dan TGA. Hasil pengujian aktivitas memperlihatkan bahwa katalis Ni/-Al2O3 menghasilkan aktivitas yang paling baik dengan rata - rata konversi toluen 96%. Penambahan promotor CaO 2% dan 5% berat menurunkan aktivitas katalis Ni/-Al2O3 dan menghambat pembentukan arang, tetapi tidak mengurangi laju deaktivasi katalis. Hasil XRD katalis Ni/-Al2O3 setelah reaksi 10 jam menunjukkan tidak adanya perubahan fasa dari -Al2O3 ke -Al2O3, yang berarti katalis masih tetap stabil.Kata Kunci: perengkahan tar, katalis nikel, konversi toluen, stabilitas.
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Kalensun, Andre G., Audy D. Wuntu e Vanda S. Kamu. "ISOTERM ADSORPSI TOLUENA PADA ARANG AKTIF STROBILUS PINUS (Pinus merkusii)". JURNAL ILMIAH SAINS 12, n. 2 (31 ottobre 2012): 100. http://dx.doi.org/10.35799/jis.12.2.2012.562.
Testo completoAbstract (sommario):
ISOTERM ADSORPSI TOLUENA PADA ARANG AKTIF STROBILUS PINUS (Pinus merkusii) ABSTRAK Adsorpsi senyawa organik volatil toluena pada arang aktif yang dibuat dari strobilus pinus telah diteliti. Dalam penelitian ini arang aktif strobilus pinus dikarbonisasi pada suhu 400 0C dan diaktivasi dengan larutan ZnCl2. Eksperimen adsorpsi selama 24 jam dalam wadah tertutup berukuran 6.5 L yang berisi gas toluena 0.4; 0.8; 1.2; 1.6 dan 2 mL. Data yang diperoleh diuji dengan model isoterm adsorpsi Dubinin-Raduskevich. Untuk kapasitas dan energi adsorpsi toluena dihitung dengan persamaan Dubinin-Raduskevich. Hasil eksperimen menunjukkan bahwa kapasitas adsorpsi (W0) arang aktif strobilus pinus yang teraktivasi adalah 0,1027 cm3/g dan energi adsorpsi (E0) adalah 13,286 kJ/mol. Sedangkan kapasitas adsorpsi (W0) arang strobilus pinus tanpa pengaktivasi adalah 0,0267 cm3/g dan energi adsorpsi (E0) adalah 5,941 kJ/mol. Kata kunci: arang aktif, strobilus pinus (Pinus merkusii), adsorpsi ISOTHERM ADSORPTION OF TOLUENE ONTO ACTIVATED CARBON MADE FROM STROBILUS PINE (Pinus merkusii) ABSTRACT The adsorption isotherm of toluene, an organic volatile compound, onto activated carbon prepared from strobilus pine was investigated. In this research, the carbon was carbonized at 400 oC and activated by ZnCl2. The adsorption isotherm experiment was conducted for 24 hours in six 6.5 L-closed chambers, each was filled with 0.4; 0.8; 1.2; 1.6 and 2.0 mL of toluene. The data were fitted to Dubinin-Raduskevich adsorption isotherm model in order to measure the adsorption capacity and the adsorption energy. The results showed that the adsorption capacity and the adsorption energy for the activated strobilus pine were 0.1027 cm3/g and 13.286 kJ/mol respectively, while for the unactivated strobilus pine were 0.0267 cm3/g and 5.941 kJ/mol respectively. Key word: activated carbon, strobilus pine (Pinus merkusii), adsorption.
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Young, Jay A. "Toluene". Journal of Chemical Education 84, n. 5 (maggio 2007): 760. http://dx.doi.org/10.1021/ed084p760.
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von Burg, R. "Toluene". Journal of Applied Toxicology 13, n. 6 (novembre 1993): 441–46. http://dx.doi.org/10.1002/jat.2550130612.
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Nguyen, Thao, Mario Aparicio e Mahmoud A. Saleh. "Gas Phase Ionization of Toluene: Benzylium Versus Tropylium Pathway". Current Physical Chemistry 9, n. 2 (14 novembre 2019): 138–50. http://dx.doi.org/10.2174/1877946809666190722140957.
Testo completoAbstract (sommario):
Aim: In this investigation, we used accurate mass high-resolution gas chromatography mass spectrometry to study the gas phase carbocations rearrangements and fragmentation of toluene and halo-toluenes as well as their deuterium labeled compounds. Objective: Accurate mass of selected ions from ionization of toluene and related compounds revealed that the initially formed radical cation C7H8 +. does not rearrange to tropylium radical cation contradicting published literature. Methods: When the toluene radical cation was purely selected, it was found to lose a free radical (hydrogen atom) at collision energies greater than 5 eV and forming benzylium or tropylium cation C7H7 + (m/z = 91), with no other fragmentations. Results: The resulting cation at collision energy greater than 20 eV fragmented by losing acetylene or ethylene or allene molecule to form C5H5 + (m/z = 65), C5H3 + (m/z = 63) or C4H3 + (m/z = 51) respectively. Purely selected C5H5 + cation at collision energy greater than 30 eV lost acetylene molecule and formed C3H3 + (m/z =39). Conclusion: In this investigation toluene, halotoluene and their deuterated derivatives (structural isomers) were found to ionize in the gas phase with isomer retention. Historically, it has been suggested that the seven carbons and hydrogen atoms would become indistinguishable. However, this should be revised in the light of new technologies.
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Alexiou, A., e A. Williams. "Soot formation in shock-tube pyrolysis of toluene, toluene-methanol, toluene-ethanol, and toluene-oxygen mixtures". Fuel and Energy Abstracts 37, n. 3 (maggio 1996): 209. http://dx.doi.org/10.1016/0140-6701(96)88920-x.
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Alexiou, A. "Soot formation in shock-tube pyrolysis of toluene, toluene-methanol, toluene-ethanol, and toluene-oxygen mixtures". Combustion and Flame 104, n. 1-2 (gennaio 1996): 51–65. http://dx.doi.org/10.1016/0010-2180(95)00004-6.
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Liao, Jian, Guang Zhong Xie, Ya Dong Jiang, Tao Zhu, Wei Zhi Li e Hui Ling Tai. "Preparation and Investigation of Toluene-Sensing Properties of Polymer/Inorganic Composite and Multi-Layer Films". Key Engineering Materials 531-532 (dicembre 2012): 570–73. http://dx.doi.org/10.4028/www.scientific.net/kem.531-532.570.
Testo completoAbstract (sommario):
In this paper, poly 4-vinylphenol (P4VP)/multi-wall carbon nanotubes (MWNTs) composite film, P4VP/ carbon black (CB) composite film and P4VP/MWNTs multi-layer sensitive films prepared using airbrush technology were deposited on interdigitated electrodes to detect tolunene vapor at room temperature. The surface of the composite film was observed under a scanning electron microscope (SEM). It was found that the resistance of the sensor increased after the exposure to toluene vapor and the increased magnitude of the changes had a good linearity with concentrations of toluene. Meanwhile, the P4VP/MWNTs composite film sensor also has a higher sensitivity than P4VP/CB composite film sensor. P4VP/MWNTs three-layer film sensor was fabricated as well. It was estimated that the response time and recovery time of P4VP/MWNTs three-layer films sensor were about 15 s and 20 s, respectively. The sensor responses of S=0.12% at 10mg/m3 toluene vapor for P4VP/MWNTs three-layer films. The results showed that the multi-layer films sensor exhibited a lower detection limit and better sensing properties compared with the sensors based composite film.
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FOO, S. C., W. O. PHOON e N. Y. KHOO. "Toluene in Blood after Exposure to Toluene". American Industrial Hygiene Association Journal 49, n. 5 (maggio 1988): 255–58. http://dx.doi.org/10.1080/15298668891379701.
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Sagert, Norman H., Michael J. Quinn, Giuliano G. Sanipelli, Walter Kremers, Wayne D. Buchannon e John B. Westmore. "Gamma-radiolysis of toluene and deuterated toluenes—II. Liquid products". International Journal of Radiation Applications and Instrumentation. Part C. Radiation Physics and Chemistry 38, n. 5 (gennaio 1991): 449–55. http://dx.doi.org/10.1016/1359-0197(91)90060-f.
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Sagert, Norman H., Roy MacFarlane e Walter Kremers. "Gamma radiolysis of toluene and deuterated toluenes—I. Isotopic exchange". International Journal of Radiation Applications and Instrumentation. Part C. Radiation Physics and Chemistry 38, n. 4 (gennaio 1991): 407–11. http://dx.doi.org/10.1016/1359-0197(91)90116-j.
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Reyna Peña, Fátima Isabella, Antonio Atienza-Márquez, Sunpil Jang, Ryuhei Shiono, Kaito Shigemasa, Takuto Araki, Kensaku Nagasawa e Shigenori Mitsushima. "Visualization of Hydrogen Bubbles Using Synchrotron X-Ray CT inside Porous Transport Layer of Direct Toluene Electro-Hydrogenation Electrolyzers". ECS Meeting Abstracts MA2023-02, n. 42 (22 dicembre 2023): 2105. http://dx.doi.org/10.1149/ma2023-02422105mtgabs.
Testo completoAbstract (sommario):
Toluene is a highly versatile solvent commonly used in many industries due to its high energy density and effective hydrogen carrier properties. It can store a considerable amount of hydrogen in a relatively small volume, making it a promising hydrogen carrier for various applications. Toluene's high volumetric energy density also makes it one of the best hydrogen carriers available. Additionally, toluene is easy to handle and transport as it is a liquid at room temperature, and it can be stored and transported like any other liquid fuel. Furthermore, toluene is a safer alternative for hydrogen storage compared to other hydrocarbons due to its low toxicity. Direct toluene-electro hydrogenation electrolyzer is a promising method that enables the simultaneous performance of water electrolysis and toluene hydrogenation in a single system. However, during the toluene direct electrolytic hydrogenation process, the formation of hydrogen bubbles from the electrolysis of water hinders the toluene hydrogenation reaction, leading to a reduced conversion rate of methylcyclohexane (MCH) and Faraday efficiency. In this study, we aimed to understand the conditions for hydrogen bubble generation and transport. We quantitatively evaluated the generation amount and distribution of hydrogen bubbles by visualizing them in an operating electrochemical cell using Synchrotron X-ray CT. Figure 1 displays the distribution of hydrogen bubbles along the porous transport layer (PTL) of the electrochemical cell. These bubbles were visualized using the raw images obtained from Spring-8 and subsequently reconstructed. The cell was operating at a current density of 200 mA/cm2 for a period of 30 minutes with pure water supplied to the anode side. Darker areas in the images indicate regions with hydrogen bubbles, which have a lower density and atomic weight than other substances in the PTL. Therefore, they are more transparent to X-rays and appear darker in the image. Higher current values and longer operation times led to increased hydrogen bubble generation, with a significant increase observed at 30 minutes. By visualizing these hydrogen bubbles, we were able to evaluate the generation distribution, amount, and transport of hydrogen, which can help improve the direct toluene-electro hydrogenation electrolyzer system. Acknowledgement This study was based on results obtained from the Development of Fundamental Technology for Advancement of Water Electrolysis Hydrogen Production in Advancement of Hydrogen Technologies and Utilization Project (P14021) commissioned by the New Energy and Industrial Technology Development Organization (NEDO). References Nagasawa K, Sugita Y, Atienza-Márquez A, Kuroda Y, Mitsushima S. Effect of the cathode catalyst loading on mass transfer in toluene direct electrohydrogenation. Journal of Electroanalytical Chemistry 2023:117431. https://doi.org/10.1016/J.JELECHEM.2023.117431. Shigemasa, A. Atienza-Márquez, K. Inoue, S. Jang, F. Reyna-Peña, T. Araki, “Visualization of dragged water and generated hydrogen bubbles in a direct toluene electro-hydrogenation electrolyzer,” J. Power Sources 2023; 554:232304. https://doi.org/10.1016/j.jpowsour.2022.232304. Nagasawa, A. Kato, Y. Nishiki, Y. Matsumura, M. Atobe, S. Mitsushima, “The effect of flow-field structure in toluene hydrogenation electrolyzer for energy carrier synthesis system. Electrochemical Acta 2017; 246:459-65. https://doi.org/10.1016/j.electacta.2017.06.081. Nagasawa, K. Tanimoto, J. Koike, K. Ikegami, S. Mitushima, “Toluene permeation through solid polymer electrolyte during toluene direct electro-hydrogenation for energy carrier synthesis”, Journal of Power Sources, Vol.439, (2019) 22707. https://doi.org/10.1016/j.jpowsour.2019.227070. Figure 1 SPring-8 CT Visualization Reconstructed image after 30 minutes of operation at 200 mA/cm². Figure 1
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Do, Si-Hyun, e Sung-Ho Kong. "The oxidation of toluene sorbed on activated carbon in the presence of H2O2 and manganese oxide". Water Science and Technology 66, n. 11 (1 dicembre 2012): 2349–54. http://dx.doi.org/10.2166/wst.2012.467.
Testo completoAbstract (sommario):
We investigated the oxidation of toluene sorbed on activated carbon (AC) in the presence of hydrogen peroxide (H2O2) and pyrolusite (MnO2). Sorbed toluene was prepared by reacting a toluene-saturated solution and AC. The amounts of sorbed toluene (mg of toluene/g of AC) decreased as the amounts of AC were increased. The reaction was conducted in a gas-purging (GP) reactor and the gas flow at the outlet of a GP reactor was carefully maintained. As a result, the percentage of toluene captured by ORBO tube was 28% in the control system with pure water. When H2O2 was catalyzed by AC (i.e. this forms a hydroxyl radical by electron transfer), approximately 17% of the desorbed toluene was oxidized and 68% of toluene remained on AC which was similar to the control system. However, when pyrolusite (650 mg/L) was added together with H2O2 (10,000 mg/L), only 5% of toluene was captured by the ORBO tube and 55% of toluene remained on AC, which indicated that both desorbed and sorbed toluene was oxidized. Moreover, toluene oxidation increased when concentrations of pyrolusite and H2O2 were increased. It was suggested that superoxide anion, which is generated by the reaction of H2O2 and pyrolusite, might stimulate toluene desorption and then toluene in the aqueous phase could be oxidized by hydroxyl radical.
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FURUSAWA, Teruo. "Toluene Diisocyanate". Journal of Synthetic Organic Chemistry, Japan 45, n. 10 (1987): 1008–10. http://dx.doi.org/10.5059/yukigoseikyokaishi.45.1008.
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Millichap, J. Gordon. "Toluene Embryopathy". Pediatric Neurology Briefs 8, n. 2 (1 febbraio 1994): 14. http://dx.doi.org/10.15844/pedneurbriefs-8-2-9.
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Gospe, S. M., C. M. Filley e N. L. Rosenberg. "Toluene dementia". Neurology 40, n. 8 (1 agosto 1990): 1320. http://dx.doi.org/10.1212/wnl.40.8.1320-b.
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Filley, C. M., e N. L. Rosenberg. "Toluene dementia". Neurology 40, n. 8 (1 agosto 1990): 1321. http://dx.doi.org/10.1212/wnl.40.8.1321.
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Hersh, Joseph H., Philip E. Podruch, George Rogers e Bernard Weisskopf. "Toluene embryopathy". Journal of Pediatrics 106, n. 6 (giugno 1985): 922–27. http://dx.doi.org/10.1016/s0022-3476(85)80238-9.
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Chen, Hai Feng. "Study of Toluene Removal by Bipolar Corona Discharge Coupled with Photocatalytic". Advanced Materials Research 955-959 (giugno 2014): 2357–61. http://dx.doi.org/10.4028/www.scientific.net/amr.955-959.2357.
Testo completoAbstract (sommario):
Experimental study the degradation efficiency of toluene by bipolar corona discharge coupled with TiO2 photocatalysis. Bipolar corona discharge can degrade the toluene efficiently and rapidly, the final products are mainly carbon dioxide and water. Toluene removal efficiency reduces when the initial concentration of toluene increasing, while toluene removal quantity is increased. Removal of toluene decreases with the gas flow rate increasing, the removal quantity first increases and then decreases. Bipolar corona discharge and a photocatalytic coupling can inprove the degradation efficiency further. Increase of the applied voltage help to improve the removal of toluene, and also to improve the coupling effect of the photocatalyst. In optimized conditions, the removal efficiency of toluene can be more than 90%. The chemical reaction process of the toluene oxidation and the TiO2 catalysis mechanism are discussed. It is pointed out that the OH* produced by corona discharge has important significance for rapid oxidation of toluene.
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Lukmandaru, Ganis, Arsyi Rahman Mohammad, Pito Wargono e Vendy Eko Prasetyo. "Studi Mutu Kayu Jati di Hutan Rakyat Gunungkidul. V. Sifat Kimia Kayu". Jurnal Ilmu Kehutanan 10, n. 2 (21 novembre 2016): 108. http://dx.doi.org/10.22146/jik.16511.
Testo completoAbstract (sommario):
Penelitian ini bertujuan untuk mengeksplorasi sifat kimia kayu jati dari hutan rakyat Kabupaten Gunungkidul. Pohon (dbh 28-37 cm) diambil dari tempat tumbuh berbeda yaitu Nglipar, Panggang, dan Playen. Setiap tempat diambil 3 pohon sebagai ulangan dan sampel yang digunakan adalah disk yang diambil dari bagian pangkal. Penampang radial disk dibagi menjadi 3 bagian, yaitu gubal, teras luar, dan teras dalam. Sifat kimia yang diuji adalah kadar holoselulosa, á-selulosa, hemiselulosa, lignin, ekstraktif etanol-toluena, kelarutan dalam air panas, kelarutan dalam NaOH 1%, dan abu. Sebagai pembanding, digunakan kayu jati dewasa dari tegakan Randublatung (Perhutani). Kisaran nilai kimia dari komponen dinding sel kayu jati Gunungkidul adalah kadar holoselulosa 75,76-79,74%, á-selulosa 46,72-50,90%, hemiselulosa 27,41-30,14%, lignin 29,22-32,80%, dan kelarutan dalam NaOH 1% sebesar 16,43-17,35%. Selanjutnya, kadar ekstraktif etanol-toluena, kelarutan dalam air panas, dan abu adalah 5,04-10,77%, 2,74-7,85%, dan 0,60-1,66%, secara berurutan. Interaksi antara kedua faktor berpengaruh nyata pada kadar holoselulosa, á-selulosa, hemiselulosa, dan ekstraktif etanol-toluena. Faktor tempat tumbuh berpengaruh nyata pada kadar abu sedangkan faktor radial berpengaruh nyata pada kadar kelarutan dalam air panas dan abu. Kayu jati dari Gunungkidul memberikan nilai rerata kadar ekstraktif etanol-toluena dan abu yang lebih rendah sedangkan nilai di parameter lainnya masih dalam kisaran nilai kayu jati dari Randublatung.Kata kunci: Tectona grandis, sifat kimia, hutan rakyat, arah radial, Gunungkidul AbstractThis study aimed to explore the chemical properties of teak wood grown in community forests from Gunungkidul Regency. Trees (dbh 28-37 cm) were selected from three different sites i.e. Nglipar, Panggang, and Playen. Three trees were cut from each site and disks were taken from the base of the trees. The disk in radial cross section was divided into 3 parts: sapwood, outer heartwood, and inner heartwood. Chemical properties tested were holocellulose, á-cellulose, hemicellulose, lignin, ethanol-toluene extractives, hot-water soluble extractives, solubility in NaOH 1%, and ash contents. Mature teakwoods from Randublatung (Perhutani plantation) were used for comparison purpose.The values range of chemical composition in the cell wall components of the Gunungkidul teak wood were holocellulose content 75.76-79.74%, , á-cellulose content 46.72-50.90%, hemicellulose content 27.41-30.14%, lignin content 29.22-32.80%, and solubility in NaOH 1% 16.43-17.35%. Further, the ethanol-toluene extractive, hot-water soluble, and ash content values ranged from 5.04 to 10.77%, 2.74-7.85%, and 0.60-1.66%, consecutively. Interaction between two factors affects significantly to holocellulose, á-cellulose, hemicellulose, and ethanol-toluene extractive contents. The growth-site significantly influence on the ash contents as radial factor has significantly affect on the levels of hot water soluble extractives and ash content. The amounts of ethanol-toluene extractive and ash contents of Gunungkidul teak wood showed the lower values than those of teak from Randublatung. The values of other parameters were remain in the range of value of teak from Randublatung.
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Burnett, Christina L., Wilma F. Bergfeld, Donald V. Belsito, Curtis D. Klaassen, James G. Marks, Ronald C. Shank, Thomas J. Slaga, Paul W. Snyder e F. Alan Andersen. "Final Amended Report of the Safety Assessment of Toluene-2,5-Diamine, Toluene-2,5-Diamine Sulfate, and Toluene-3,4-Diamine as Used in Cosmetics". International Journal of Toxicology 29, n. 3_suppl (maggio 2010): 61S—83S. http://dx.doi.org/10.1177/1091581810361964.
Testo completoAbstract (sommario):
Toluene-2,5-diamine, toluene-2,5-diamine sulfate, and toluene-3,4-diamine are diaminotoluenes used as colorants in permanent hair dyes and tints. Toluene-2,5-diamine is used in 79 products at concentrations up to 3%; toluene-2,5-diamine sulfate is used in 168 products at concentrations up to 4%. Toluene-3,4-diamine does not appear to be in current use. Previously, the Cosmetic Ingredient Review Expert Panel determined that all 3 ingredients were safe for use as hair dyes. New data suggest that differences in toxicity, especially with respect to carcinogenicity, may exist as a function of placement of amine groups around the benzene ring. The Expert Panel concluded that toluene-2,5-diamine and toluene-2,5-diamine sulfate and are safe as hair dye ingredients in the present practices of use and concentrations but that there are insufficient data supporting the safety of toluene-3,4-diamine.
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Bosch, X., J. M. Campistol, J. Montoliu e L. Revert. "Myelofibrosis and Focal Segmental Glomerulosclerosis Associated with Toluene Poisoning". Human Toxicology 7, n. 4 (luglio 1988): 357–61. http://dx.doi.org/10.1177/096032718800700411.
Testo completoAbstract (sommario):
A 60-year-old man with long-term exposure to toluene presented with both myelofibrosis and focal segmental glomerulosclerosis. There was also evidence of other toluene-related complications to support the diagnosis of toluene toxicity. The toxic effects of toluene, particularly kidney disorders and haematotoxicity, suggest a relationship between toluene, myelofibrosis and focal segmental glomerulosclerosis.
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Kobayashi, Hideki, Katsuyuki Uematsu, Hisako Hirayama e Koki Horikoshi. "Novel Toluene Elimination System in a Toluene-Tolerant Microorganism". Journal of Bacteriology 182, n. 22 (15 novembre 2000): 6451–55. http://dx.doi.org/10.1128/jb.182.22.6451-6455.2000.
Testo completoAbstract (sommario):
ABSTRACT In studies of Pseudomonas putida IH-2000, a toluene-tolerant microorganism, membrane vesicles (MVs) were found to be released from the outer membrane when toluene was added to the culture. These MVs were found to be composed of phospholipids, lipopolysaccharides (LPS), and very low amounts of outer membrane proteins. The MVs also contained a higher concentration of toluene molecules (0.172 ± 0.012 mol/mol of lipid) than that found in the cell membrane. In contrast to the wild-type strain, the toluene-sensitive mutant strain 32, which differs from the parent strain in LPS and outer membrane proteins, did not release MVs from the outer membrane. The toluene molecules adhering to the outer membrane are eliminated by the shedding of MVs, and this system appears to serve as an important part of the toluene tolerance system of IH-2000.
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Hubert, Casey, Yin Shen e Gerrit Voordouw. "Composition of Toluene-Degrading Microbial Communities from Soil at Different Concentrations of Toluene". Applied and Environmental Microbiology 65, n. 7 (1 luglio 1999): 3064–70. http://dx.doi.org/10.1128/aem.65.7.3064-3070.1999.
Testo completoAbstract (sommario):
ABSTRACT Toluene-degrading bacteria were isolated from hydrocarbon-contaminated soil by incubating liquid enrichment cultures and agar plate cultures in desiccators in which the vapor pressure of toluene was controlled by dilution with vacuum pump oil. Incubation in desiccators equilibrated with either 100, 10, or 1% (wt/wt) toluene in vacuum pump oil and testing for genomic cross-hybridization resulted in four genomically distinct strains (standards) capable of growth on toluene (strains Cstd1, Cstd2, Cstd5, and Cstd7). The optimal toluene concentrations for growth of these standards on plating media differed considerably. Cstd1 grew best in an atmosphere equilibrated with 0.1% (wt/wt) toluene, but Cstd5 failed to grow in this atmosphere. Conversely, Cstd5 grew well in the presence of 10% (wt/wt) toluene, which inhibited growth of Cstd1. 16S ribosomal DNA sequencing and cross-hybridization analysis indicated that both Cstd1 and Cstd5 are members of the genus Pseudomonas. An analysis of the microbial communities in soil samples that were incubated with 10% (wt/wt) toluene with reverse sample genome probing indicated thatPseudomonas strain Cstd5 was the dominant community member. However, incubation of soil samples with 0.1% (wt/wt) toluene resulted in a community that was dominated by Pseudomonas strain Q7, a toluene degrader that has been described previously (Y. Shen, L. G. Stehmeier, and G. Voordouw, Appl. Environ. Microbiol. 64:637–645, 1998). Q7 was not able to grow by itself in an atmosphere equilibrated with 0.1% (wt/wt) toluene but grew efficiently in coculture with Cstd1, suggesting that toluene or metabolic derivatives of toluene were transferred from Cstd1 to Q7.
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Woods, Angela, Maribeth Watwood e Egbert Schwartz. "Identification of a Toluene-Degrading Bacterium from a Soil Sample through H218O DNA Stable Isotope Probing". Applied and Environmental Microbiology 77, n. 17 (8 luglio 2011): 5995–99. http://dx.doi.org/10.1128/aem.05689-11.
Testo completoAbstract (sommario):
ABSTRACTDNA stable isotope probing (DNA-SIP) with H218O was used to identify a toluene-degrading bacterium in soil amended with 48 ppm toluene. After quantification of toluene degradation rates in soil, DNA was extracted from soil incubated with H218O, H216O, H216O and 48 ppm toluene, or H218O and 48 ppm toluene. A single DNA band formed along a cesium chloride gradient after isopycnic centrifugation of extracts from soils incubated with H216O. With extracts from soils to which only H218O was added, two distinct DNA bands formed, while three bands formed when DNA extracted from soil incubated with both H218O and toluene was analyzed. We suggest that this third band formed because toluene does not contain any oxygen atoms and toluene-degrading organisms had to transfer oxygen atoms from H218O into metabolic intermediates to form nucleic acidsde novo. We extracted the third DNA band and amplified a large fraction of the bacterial 16S rRNA gene. Direct sequencing of the PCR product obtained from the labeled DNA, as well as cloned 16S rRNA amplicons, identified a known toluene degrader,Rhodococcus jostiiRHA1. A toluene-degrading bacterial strain was subsequently isolated from soil and shown to beRhodococcus jostiiRHA1. Finally, quantitative real-time PCR analysis showed that the abundance of the 16S rRNA gene ofRhodococcus jostiiRHA1 increased in soil after toluene exposure but not in soils from which toluene was withheld. This study indicates that H218O DNA-SIP can be a useful method for identifying pollutant-degrading bacteria in soil.
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Poon, Raymond, Ih Chu, Stephen Bjarnason, Marc Potvin, Renaud Vincent, Richard B. Miller e Victor E. Valli. "Inhalation Toxicity Study of Methanol, Toluene, and Methanol/Toluene Mixtures in Rats: Effects of 28-Day Exposure". Toxicology and Industrial Health 10, n. 3 (maggio 1994): 231–45. http://dx.doi.org/10.1177/074823379401000310.
Testo completoAbstract (sommario):
The inhalation toxicity of methanol and toluene was investigated in rats. Young Sprague Dawley rats of both sexes were exposed to vapors of methanol (300 ppm, 3000 ppm), toluene (30 ppm, 300 ppm) or methanol/toluene (300/30 ppm, 300/300 ppm, 3000/30 ppm, and 3000/300 ppm) six hrs per day, five days/week for four weeks. Control animals inhaled air only. Increased serum alkaline phosphatase activity was observed in males exposed to high-dose toluene, and decreased creatinine was noted in the group exposed to high-dose methanol/toluene. The thyroid gland in females appeared to be a target organ for inhaled methanol, toluene, and methanol/toluene, although the changes were confined to a mild, and occasionally moderate, reduction in follicle size. Histopathological changes of the nasal passages, consisting of subepithelial nonsuppurative inflammation, occurred in higher incidences in rats exposed to methanol/toluene than in those exposed to the individual vapors. Inhalation of methanol, toluene, or methanol/toluene produced no changes in liver weights, hepatic mixed-function oxidases, or serum aspartate transaminase activities, and onlly minimal changes in liver histopathology. The only liver changes were decreased liver weight and increased cytoplasmic density of the periportal areas in females exposed to high-dose methanol/toluene. These data indicated that exposure to methanol, toluene, or a mixture of both produced mild biochemical effects and histological changes in the thyroid and nasal passage. No apparent interactive effects were observed.
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Fu, Cheng Bi, Tao Liu, Xiao Bai Li, Jing Zhu e Jing Jing Liang. "Research on Coking Behavior over Catalysts for Toluene Disproportionation". Applied Mechanics and Materials 529 (giugno 2014): 8–12. http://dx.doi.org/10.4028/www.scientific.net/amm.529.8.
Testo completoAbstract (sommario):
Effects of pressure of toluene, reaction temperature and nature of catalysts on coking over catalysts in toluene disproportionation are studied by using the method of thermogravimetry. Experiment results show that during the toluene disproportionation, the coking amount over catalysts increases with partial pressure of toluene and reaction temperature and the initial coking temperature decreases with partial pressure of toluene. Coking results mainly from the relatively stronger acid sites on the surface of the catalyst. Both HZSM-5 and HM catalysts have efficiency for toluene disproportionation, but HZM-5 catalyst has higher catalytic activity and stability.
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Shingleton, Justin T., Bruce M. Applegate, Aaron C. Nagel, Paul R. Bienkowski e Gary S. Sayler. "Induction of the tod Operon by Trichloroethylene in Pseudomonas putida TVA8". Applied and Environmental Microbiology 64, n. 12 (1 dicembre 1998): 5049–52. http://dx.doi.org/10.1128/aem.64.12.5049-5052.1998.
Testo completoAbstract (sommario):
ABSTRACT Bioluminescence, mRNA levels, and toluene degradation rates inPseudomonas putida TVA8 were measured as a function of various concentrations of toluene and trichloroethylene (TCE). TVA8 showed an increasing bioluminescence response to increasing TCE and toluene concentrations. Compared to uninduced TVA8 cultures,todC1 mRNA levels increased 11-fold for TCE-treated cultures and 13-fold for toluene-treated cultures. Compared to uninduced P. putida F1 cultures, todC1 mRNA levels increased 4.4-fold for TCE-induced cultures and 4.9-fold for toluene-induced cultures. Initial toluene degradation rates were linearly correlated with specific bioluminescence in TVA8 cultures.
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Nugraha, Nugraha, Adhitya Gandaryus Saputro, Mohammad Kemal Agusta, Fiki Taufik Akbar e Aditya Dimas Pramudya. "Density Functional Study on Benzene, Toluene, Ethylbenzene and Xylene Adsorptions on ZnO(100) Surface". Molekul 14, n. 1 (4 giugno 2019): 37. http://dx.doi.org/10.20884/1.jm.2019.14.1.501.
Testo completoAbstract (sommario):
We study the interaction between benzene, toluene, ethylbenzene and xylene (BTEX) molecules with ZnO(100) surface by means of density functional theory-based calculations. We find that these interactions result in the physical adsorptions of BTEX gases with adsorption distances larger than 2 Å. These adsorptions are governed by the van der Waals interaction instead of the covalent interaction. We also find that the trend of the strength of BTX adsorptions on ZnO(100) surface is in line with the experimental trend of sensitivity of ZnO material towards BTX gases (benzene < tolune < xylene). We explain this relation by using one of the sensing mechanism within the ionosorption model. By using this relation, we also predict that the response of ZnO towards ethylbenzene will be similar to the response towards toluene since these two molecules have similar adsorption energies on ZnO(100) surface.
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MIYAURA, SHUICHI, e HIDEO ISONO. "Tissue distribution of toluene in rats after toluene inhalation." Eisei kagaku 33, n. 5 (1987): 337–41. http://dx.doi.org/10.1248/jhs1956.33.337.
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Tardif, R., G. L. Plaa e J. Brodeur. "Influence of varions mixtures of inhaled toluene and xylene on the biological monitoring of exposure to these solvents in rats". Canadian Journal of Physiology and Pharmacology 70, n. 3 (1 marzo 1992): 385–93. http://dx.doi.org/10.1139/y92-048.
Testo completoAbstract (sommario):
The present study was undertaken to describe the influence of simultaneous exposure by inhalation to toluene and xylene on some aspects of their respective metabolic disposition. Adult male rats were exposed acutely (5 h) to 75, 150, and 225 ppm of toluene or xylene and to various mixtures of these solvents: toluene (75 ppm) and xylene (225 ppm), toluene (150 ppm) and xylene (150 ppm), toluene (225 ppm) and xylene (75 ppm). Compared with single exposure, simultaneous exposure resulted in lower amounts of excreted hippuric acid (20–30%) and methylhippuric acids (4–40%) in urine over a period of 24 h, even though significant differences were seen only with the toluene (150 ppm) and xylene (150 ppm) combination. In addition, increased concentrations of solvents in blood (toluene, 230%; xylene, 500%) and in brain (toluene, 230%; xylene, 320%) were found during the immediate post-exposure period. Simultaneous exposure also enhanced the pulmonary elimination of both solvents (toluene, 190–240%; xylene, 340–650%). Influence of repeated simultaneous exposure (9 days) was investigated for the toluene (150 ppm) and xylene (150 ppm) combination and the results compared with those of repeated exposure to each solvent administered singly. Under these conditions, repeated simultaneous exposure decreased the excretion of urinary metabolites, but only after the first exposure. On the other hand, simultaneous exposure resulted in significantly higher concentrations of toluene (210%) and xylene (240%) in blood throughout the entire 9-day exposure period. These results strongly suggest mutual metabolic interactions (inhibition) between toluene and xylene that affect the metabolic disposition of both solvents and ultimately the biological monitoring of data of exposure to a combination of solvents in rats.Key words: toluene, xylene, simultaneous exposure, biological monitoring, metabolic interaction, inhalation.
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Raschke, Henning, Thomas Fleischmann, Jan Roelof Van Der Meer e Hans-Peter E. Kohler. "cis-Chlorobenzene Dihydrodiol Dehydrogenase (TcbB) from Pseudomonas sp. Strain P51, Expressed in Escherichia coli DH5α(pTCB149), Catalyzes Enantioselective Dehydrogenase Reactions". Applied and Environmental Microbiology 65, n. 12 (1 dicembre 1999): 5242–46. http://dx.doi.org/10.1128/aem.65.12.5242-5246.1999.
Testo completoAbstract (sommario):
ABSTRACT cis-Chlorobenzene dihydrodiol dehydrogenase (CDD) fromPseudomonas sp. strain P51, cloned into Escherichia coli DH5α(pTCB149) was able to oxidizecis-dihydrodihydroxy derivatives (cis-dihydrodiols) of dihydronaphthalene, indene, and fourpara-substituted toluenes to the corresponding catechols. During the incubation of a nonracemic mixture ofcis-1,2-indandiol, only the (+)-cis-(1R,2S) enantiomer was oxidized; the (−)-cis-(S,2R) enantiomer remained unchanged. CDD oxidized both enantiomers ofcis-1,2-dihydroxy-1,2,3,4-tetrahydronaphthalene, but oxidation of the (+)-cis-(1S,2R) enantiomer was delayed until the (−)-cis-(1R,2S) enantiomer was completely depleted. When incubated with nonracemic mixtures ofpara-substituted cis-toluene dihydrodiols, CDD always oxidized the major enantiomer at a higher rate than the minor enantiomer. When incubated with racemic 1-indanol, CDD enantioselectively transformed the (+)-(1S) enantiomer to 1-indanone. This stereoselective transformation shows that CDD also acted as an alcohol dehydrogenase. Additionally, CDD was able to oxidize (+)-cis-(1R,2S)-dihydroxy-1,2-dihydronaphthalene, (+)-cis-monochlorobiphenyl dihydrodiols, and (+)-cis-toluene dihydrodiol to the corresponding catechols.
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Gospe, Sidney M., e Mohammed A. S. Al-Bayati. "Comparison of Oral and Inhalation Exposures to Toluene". Journal of the American College of Toxicology 13, n. 1 (febbraio 1994): 21–32. http://dx.doi.org/10.3109/10915819409140651.
Testo completoAbstract (sommario):
Male Fisher-344 rats were exposed to [14C]toluene by either liquid gavage or vapor inhalation and blood toluene levels were measured by radiospectroscopy. Oral doses of 110, 336, 741, and 911 mg toluene/kg body weight were administered to 82 rats by gavage and blood toluene levels were followed for 6 h. For the inhalation group (120 rats), 3-h exposures to 99, 549, and 1,145 ppm were given and blood toluene levels were measured during this 3-h uptake phase and during a 4-h elimination period. The data for these two exposure methods were fitted to parametric kinetic models, and the resulting curves were then integrated. The blood toluene versus time profiles for oral and inhalation exposures were then compared and the equation: In(oral dosage, mg/kg) = -1.44 + 0.95 In(3-h inhalation exposure concentration, ppm) was derived (where In represents the natural logarithm). This equation describes the relation between toluene inhalation and oral exposure methods used in this study. This investigation demonstrates that oral toluene administration produces high blood toluene concentrations that can simulate the blood levels achieved after inhalation exposure to this solvent.
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Liu, Zhengwei, Xiaoyu Lin, Xinzhe Wang, Mingbo Sun, Shici Ma e Shucai Zhang. "Shift in Bacterial Community Structure in the Biodegradation of Benzene and Toluene under Sulfate-Reducing Condition". Toxics 12, n. 6 (10 giugno 2024): 423. http://dx.doi.org/10.3390/toxics12060423.
Testo completoAbstract (sommario):
Groundwater contaminated by benzene and toluene is a common issue, posing a threat to the ecosystems and human health. The removal of benzene and toluene under sulfate-reducing condition is well known, but how the bacterial community shifts during this process remains unclear. This study aims to evaluate the shift in bacterial community structure during the biodegradation of benzene and toluene under sulfate-reducing condition. In this study, groundwater contaminated with benzene and toluene were collected from the field and used to construct three artificial samples: Control (benzene 50 mg/L, toluene 1.24 mg/L, sulfate 470 mg/L, and HgCl2 250 mg/L), S1 (benzene 50 mg/L, toluene 1.24 mg/L, sulfate 470 mg/L), and S2 (benzene 100 mg/L, toluene 2.5 mg/L, sulfate 940 mg/L). The contaminants (benzene and toluene), geochemical parameters (sulfate, ORP, and pH), and bacterial community structure in the artificial samples were monitored over time. By the end of this study (day 90), approximately 99% of benzene and 96% of toluene could be eliminated in both S1 and S2 artificial samples, while in the Control artificial sample the contaminant levels remained unchanged due to microbial inactivation. The richness of bacterial communities initially decreased but subsequently increased over time in both S1 and S2 artificial samples. Under sulfate-reducing condition, key players in benzene and toluene degradation were identified as Pseudomonas, Janthinobacterium, Novosphingobium, Staphylococcus, and Bradyrhizobium. The results could provide scientific basis for remediation and risk management strategies at the benzene and toluene contaminated sites
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Vanoirbeek, Jeroen A. J., Vanessa De Vooght, Nicholas Synhaeve, Benoit Nemery e Peter H. M. Hoet. "Is Toluene Diamine a Sensitizer and is there Cross-Reactivity between Toluene Diamine and Toluene Diisocyanate?" Toxicological Sciences 109, n. 2 (30 marzo 2009): 256–64. http://dx.doi.org/10.1093/toxsci/kfp065.
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Bhargavi, Kandukuri, Debjyoti Ray, Piu Chawdhury, Sairam Malladi, Thatikonda Shashidhar e Challapalli Subrahmanyam. "Oxidation of Toluene by Ozone over Surface-Modified γ-Al2O3: Effect of Ag Addition". Catalysts 12, n. 4 (8 aprile 2022): 421. http://dx.doi.org/10.3390/catal12040421.
Testo completoAbstract (sommario):
In this study, the ability of ozone to oxidise toluene present in low levels into CO and CO2 was studied. The catalytic ozonation of toluene was carried out in a micro-fixed bed reactor. The oxidation was done in two steps: toluene adsorption on the catalyst followed by sequential ozone desorption. Toluene breakdown by ozone at low temperature and atmospheric pressure was achieved using γ-Al2O3 supported transition metal oxides impregnated with a reduced noble metal. The catalyst Ag–CoOx/γ-Al2O3 efficiently oxidised and transformed toluene into products (52.4% COx yield). This catalyst has a high surface area, more acidic sites, and lattice oxygens for better toluene oxidation. The addition of Ag to the CoOx/γ-Al2O3 catalyst surface improved toluene adsorption on the catalyst surface, resulting in improved product yield, selectivity, and carbon balance.
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Mosqueda, Gilberto, e Juan-Luis Ramos. "A Set of Genes Encoding a Second Toluene Efflux System in Pseudomonas putida DOT-T1E Is Linked to the tod Genes for Toluene Metabolism". Journal of Bacteriology 182, n. 4 (15 febbraio 2000): 937–43. http://dx.doi.org/10.1128/jb.182.4.937-943.2000.
Testo completoAbstract (sommario):
ABSTRACT Sequence analysis in Pseudomonas putida DOT-T1E revealed a second toluene efflux system for toluene metabolism encoded by the ttgDEF genes, which are adjacent to thetod genes. The ttgDEF genes were expressed in response to the presence of aromatic hydrocarbons such as toluene and styrene in the culture medium. To characterize the contribution of the TtgDEF system to toluene tolerance in P. putida, site-directed mutagenesis was used to knock out the gene in the wild-type DOT-T1E strain and in a mutant derivative, DOT-T1E-18. This mutant carried a Tn5 insertion in the ttgABCgene cluster, which encodes a toluene efflux pump that is synthesized constitutively. For site-directed mutagenesis, a cassette to knock out the ttgD gene and encoding resistance to tellurite was constructed in vitro and transferred to the corresponding host chromosome via the suicide plasmid pKNG101. Successful replacement of the wild-type sequences with the mutant cassette was confirmed by Southern hybridization. A single ttgD mutant, DOT-T1E-1, and a double mutant with knock outs in the ttgD andttgA genes, DOT-T1E-82, were obtained and characterized for toluene tolerance. This was assayed by the sudden addition of toluene (0.3% [vol/vol]) to the liquid culture medium of cells growing on Luria-Bertani (LB) medium (noninduced) or on LB medium with toluene supplied via the gas phase (induced). Induced cells of the singlettgD mutant were more sensitive to sudden toluene shock than were the wild-type cells; however, noninduced wild-type andttgD mutant cells were equally tolerant to toluene shock. Noninduced cells of the double DOT-T1E-82 mutant did not survive upon sudden toluene shock; however, they still remained viable upon sudden toluene shock if they had been previously induced. These results are discussed in the context of the use of multiple efflux pumps involved in solvent tolerance in P. putida DOT-T1E.
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Chang, S. W., H. J. La e S. J. Lee. "Microbial degradation of benzene, toluene, ethylbenzene and xylene isomers (BTEX) contaminated groundwater in Korea". Water Science and Technology 44, n. 7 (1 ottobre 2001): 165–71. http://dx.doi.org/10.2166/wst.2001.0415.
Testo completoAbstract (sommario):
A mixed culture derived from a gasoline-contaminated aquifer in Korea was enriched on toluene at 25°C. A study was conducted to characterize the substrate interaction of BTEX by toluene-enriched consortia and determine the effects of initial BTEX concentration on BTEX degradation. Substrate degradation patterns in individual aromatics were found to differ significantly from patterns for aromatics in mixtures. In the experiment of a single substrate, toluene was degraded fastest, followed by benzene, ethylbenzene, and the xylenes. In BTEX mixtures, degradation followed the order of toluene, ethylbenzene, benzene, and the xylenes. The studies conducting with toluene-enriched consortia evaluated substrate interactions by the concurrent presence of multiple BTEX compounds and revealed a range of substrate interaction patterns including no interaction, stimulation, inhibition, and cometabolism. The simultaneous presence of benzene and toluene were degraded with a slight inhibitory effect on each other. Ethylbenzene was shown to be the most potent inhibitor of BTEX degradation. p-xylene also inhibited the degradation of benzene, toluene, and ethylbenzene, whereas the presence of either benzene or toluene enhanced the degradation of ethylbenzene and the xylenes.