Articoli di riviste: "Cyclohexane"

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Guo, Jia Neng, Jin Zhi Lin, Xin Liu, Qi Wei Wang, Ge Gao, Xiang Zhang, Xin Ge Shi, Bei Yang e Hai Bo Jin. "The Progress of Catalyst for Cyclohexane Dehydrogenation Processes". Advanced Materials Research 953-954 (giugno 2014): 1261–68. http://dx.doi.org/10.4028/www.scientific.net/amr.953-954.1261.

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Cyclohexane dehydrogenation is an important process in the petrochemical industry, chemical raw material such as cyclohexanol, cyclohexanone,benzene and cyclohexene can be produced from which.Divided cyclohexane dehydrogenation into catalytic dehydrogenation or oxidative dehydrogenation, homogeneous or heterogeneous reaction. Summarized vary catalysts, active constituent and process conditions in dehydrogenation process.

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Kurganova, E. A., A. S. Frolov, S. A. Kanaev, G. N. Koshel, A. A. Petukhov, G. V. Rybina, V. V. Plakhtinskii, V. S. Kabanova e A. A. Smurova. "Epoxidation of cyclohexene with cyclohexyl hydroperoxide". Fine Chemical Technologies 18, n. 6 (18 gennaio 2024): 505–16. http://dx.doi.org/10.32362/2410-6593-2023-18-6-505-516.

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Objectives. To investigate the regularities of the process of joint production of epoxycyclohexane, cyclohexanol, and cyclohexanone using the cyclohexene epoxidation reaction with cyclohexyl hydroperoxide in the presence of an ammonium paramolybdate catalyst, representing an alternative to the method of cyclohexanol and cyclohexanone synthesis by alkaline catalytic decomposition of cyclohexyl hydroperoxide.Methods. The qualitative and quantitative analysis of the obtained intermediate and target compounds was determined using modern physicochemical research methods: gas–liquid chromatography using the Chromatec-Crystal 5000.2 hardware and software complex with a flame ionization detector and infrared spectroscopy on an RX-1 infrared Fourier spectrometer. The content of hydroperoxide in the oxidation products was determined using iodometric titration, while the carboxylic acid content was determined by the titrimetric method based on the neutralization reaction.Results. The presented method for obtaining cyclohexanol and cyclohexanone together with epoxycyclohexane by the reaction of cyclohexene epoxidation with cyclohexyl hydroperoxide containing cyclohexane in the products of high-temperature liquid-phase oxidation is experimentally substantiated. The influence of various technological parameters on the process of liquid-phase oxidation of cyclohexane to hydroperoxide is described. The conditions for carrying out this reaction are determined to ensure the achievement of a content of cyclohexyl hydroperoxide of 1.5 wt % in the products of oxidation. The regularities of the epoxidation reaction of the synthesized cyclohexyl hydroperoxide with cyclohexene in the presence of an ammonium paramolybdate catalyst are analyzed.Conclusions. Epoxidation of cyclohexene with cyclohexyl hydroperoxide produced epoxycyclohexane at a yield of 80–90% and a conversion of cyclohexane hydroperoxide of 85%.

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Frolov, A. S., E. A. Kurganova, E. M. Yarkina, N. V. Lebedeva, G. N. Koshel e A. S. Kalenova. "INTENSIFICATION OF THE CYCLOHEXANE LIQUID PHASE OXIDATION PROCESS". Fine Chemical Technologies 13, n. 4 (28 agosto 2018): 50–57. http://dx.doi.org/10.32362/2410-6593-2018-13-4-50-57.

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Liquid-phase oxidation of cyclohexane to cyclohexanol and cyclohexanone was studied in the absence of solvents under an air pressure of 0.5-5 MPa, in the temperature range 115-150 °C, catalyzed by N-hydroxyphthalimide (N-HPI). It was established for the first time that the use of N-HPI as a catalyst in place of the conventionally used metal salts of variable valence allowed a 2-3-fold increase in the conversion of the initial hydrocarbon and selectivity from 70-75 to 90%. The combined use of N-HPI with cobalt(II) acetate results in an additional increase in the conversion of cyclohexane by 30-40%, the selectivity of cyclohexanol and cyclohexanone formation to 94-97%, which seems to be due to the synergistic effect between the two components of the catalyst. The mechanism of catalytic oxidation of cyclohexane to cyclohexanol and cyclohexanone is discussed. It has been suggested that N-HPI plays a dual role in the oxidation of cyclohexane: it catalyzes the conversion of cyclohexane to cyclohexanol and cyclohexanone and, on the other hand, promotes the conversion of cyclohexanol to cyclohexanone, thereby substantially reducing the formation of adipic acid and its esters, by-products of the reaction, and increases selectivity of oxidation. This also explains the unusually high (1.3-1.5 : 1) ketone: alcohol ratio in the oxidation products of cyclohexane in the presence of N-HPI. The high selectivity of the formation of the desired products, the conversion of cyclohexane, the moderate temperature, the available catalyst, suggest that this method of oxidizing cyclohexane to cyclohexanol and cyclohexanone may be of interest for further practical use.

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Wang, Lei, Ming Qiao Zhu, Jian Gang Lu e Hong Ding Hu. "Uncatalyzed Oxidation of Cyclohexane in the Microchannels". Key Engineering Materials 562-565 (luglio 2013): 1542–47. http://dx.doi.org/10.4028/www.scientific.net/kem.562-565.1542.

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The oxidation of cyclohexane in the microchannels not only improves the safety of the reaction, but also the performance of the oxidation reaction. Different gas-liquid micro mixers were used for the mixing of gas and liquid before entering into microchannels, and SIMM-V2 performed best of all. Excellent slug/plug flow can be formed in the microchannels after mixing in the gas-liquid micro mixer when the molar ratio of oxygen to cyclohexane is less than 0.5:1. The conversion of cyclohexane increased as the residence time increased, but the selectivity of cyclohexanol and cyclohexanone increased first and then decreased. At the reaction temperature of 200 °C, with the flow rate of the solvent isopropanol being 1 mL/min and the molar ratio of oxygen to cyclohexane being 0.15:1, both the conversion of cyclohexane and selectivity of cyclohexanol and cyclohexanone increased with the increase of pressure. The conversion of cyclohexane and selectivity of cyclohexanol and cyclohexanone reached 10.10% and 66.93% respectively at the pressure of 8 MPa. It is indicated that the new process by use of uncatalyzed cyclohexane oxidation in the microchannels will have very attractive prospects in the improvement of the safety, intensification of the gas-liquid mass transfer and obtaining good reactive performance. Therefore, the technology shows good potential in industrial applications.

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Aghamammadova, S. A. "MECHANISM OF BIOMIMETIC OXIDATION OF CYCLOHEXANE TO CYCLOHEXANONE BY HYDROGEN PEROXIDE". Azerbaijan Chemical Journal, n. 1 (9 aprile 2021): 61–66. http://dx.doi.org/10.32737/0005-2531-2021-1-61-66.

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The process of gas-phase oxidation of cyclohexane was studied in the presence of a heterogeneous biomimetic catalyst (per-FTPhPFe(III)OH/Al2O3), at 130–2500C, in which high yields of cyclohexanone and cyclohexanol were obtained up to 25.2% with a selectivity of ~80% at a cyclohexane conversion of 34%. The mechanism of the conversion of cyclohexane to cyclohexanone has been studied in detail, and the coherently synchronized character of the reaction proceeding is shown

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Zhang, Jiao Jing, Hua Lin Song, Jian Wang e Hua Song. "Experimental Study on Catalytic Oxidation of Cyclohexane Catalyzed by Phosphomolybdic Acid". Advanced Materials Research 549 (luglio 2012): 411–14. http://dx.doi.org/10.4028/www.scientific.net/amr.549.411.

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The catalytic oxidation of cyclohexane to cyclohexanone and cyclohexanol using hydrogen peroxide over phosphomolybdic acid were studied. Factors such as the amount of catalyst, amount of the oxidant (H2O2), reaction temperature and reaction time were investigated. The conversion of cyclohexane was 35.35%, the total selectivity to cyclohexanone and cyclohexanol was 97.68% at a reaction temperature of 70 °C, reaction time of 8 h, 10 mL of acetone, 0.01 g of phosphomolybdic acid and 0.5 mL of hydrogen peroxide.

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Henríquez, Adolfo, Victoria Melin, Nataly Moreno, Héctor D. Mansilla e David Contreras. "Optimization of Cyclohexanol and Cyclohexanone Yield in the Photocatalytic Oxofunctionalization of Cyclohexane over Degussa P-25 under Visible Light". Molecules 24, n. 12 (15 giugno 2019): 2244. http://dx.doi.org/10.3390/molecules24122244.

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The sustainable transformation of basic chemicals into organic compounds of industrial interest using mild oxidation processes has proved to be challenging. The production of cyclohexanol and cyclohexanone from cyclohexane is of interest to the nylon manufacturing industry. However, the industrial oxidation of cyclohexane is inefficient. Heterogeneous photocatalysis represents an alternative way to synthesize these products, but the optimization of this process is difficult. In this work, the yields of photocatalytic cyclohexane conversion using Degussa P-25 under visible light were optimized. To improve cyclohexanol production, acetonitrile was used as an inert photocatalytic solvent. Experiments showed that the use of the optimized conditions under solar light radiation did not affect the cyclohexanol/cyclohexanone ratio. In addition, the main radical intermediary produced in the reaction was detected by the electronic paramagnetic resonance technique.

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Alnefaie, Reem S., Mohamed Abboud, Abdullah Alhanash e Mohamed S. Hamdy. "Efficient Oxidation of Cyclohexane over Bulk Nickel Oxide under Mild Conditions". Molecules 27, n. 10 (14 maggio 2022): 3145. http://dx.doi.org/10.3390/molecules27103145.

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Nickel oxide powder was prepared by simple calcination of nickel nitrate hexahydrate at 500 °C for 5 h and used as a catalyst for the oxidation of cyclohexane to produce the cyclohexanone and cyclohexanol—KA oil. Molecular oxygen (O2), hydrogen peroxide (H2O2), t-butyl hydrogen peroxide (TBHP) and meta-chloroperoxybenzoic acid (m-CPBA) were evaluated as oxidizing agents under different conditions. m-CPBA exhibited higher catalytic activity compared to other oxidants. Using 1.5 equivalent of m-CPBA as an oxygen donor agent for 24 h at 70 °C, in acetonitrile as a solvent, NiO powder showed exceptional catalytic activity for the oxidation of cyclohexane to produce KA oil. Compared to different catalytic systems reported in the literature, for the first time, about 85% of cyclohexane was converted to products, with 99% KA oil selectivity, including around 87% and 13% selectivity toward cyclohexanone and cyclohexanol, respectively. The reusability of NiO catalyst was also investigated. During four successive cycles, the conversion of cyclohexane and the selectivity toward cyclohexanone were decreased progressively to 63% and 60%, respectively, while the selectivity toward cyclohexanol was increased gradually to 40%.

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Zhang, Jiao Jing, Bing Bai e Hua Song. "Experimental Study on Cyclohexane by Catalytic Oxidation Using H₂O₂/Ferrous Sulfate". Advanced Materials Research 233-235 (maggio 2011): 1288–91. http://dx.doi.org/10.4028/www.scientific.net/amr.233-235.1288.

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Catalytic oxidation of cyclohexane to cyclohexanone and cyclohexanol using hydrogen peroxide over ferrous sulfate catalyst at atmospheric condition was studied. Effect of the solvent volume, catalyst amount, hydrogen peroxide volume, reaction temperature, reaction time on reaction was investigated. Results showed that using 10 mL of acetone, 0.02 g of a ferrous sulfate and 0.5 mL of hydrogen peroxide at thereaction temperature of 80 °C for 8 h, the conversion of cyclohexane was 35.35%, the total selectivity of cyclohexanone and cyclohexanol was 94.06%.

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Kirkwood, Kathleen, e S. David Jackson. "Hydrogenation and Hydrodeoxygenation of Oxygen-Substituted Aromatics over Rh/silica: Catechol, Resorcinol and Hydroquinone". Catalysts 10, n. 5 (22 maggio 2020): 584. http://dx.doi.org/10.3390/catal10050584.

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The hydrogenation and hydrodeoxygenation (HDO) of dihydroxybenzene isomers, catechol (1,2-dihydroxybenzene), resorcinol (1,3-dihydroxybenzene) and hydroquinone (1,4-dihydroxybenzene) was studied in the liquid phase over a Rh/silica catalyst at 303–343 K and 3 barg hydrogen pressure. The following order of reactivity, resorcinol > catechol > hydroquinone (meta > ortho > para) was obtained. Kinetic analysis revealed that catechol had a negative order of reaction whereas both hydroquinone and resorcinol gave positive half-order suggesting that catechol is more strongly adsorbed. Activation energies of ~30 kJ·mol−1 were determined for catechol and hydroquinone, while resorcinol gave a value of 41 kJ·mol−1. Resorcinol, and similarly hydroquinone, gave higher yields of the hydrogenolysis products (cyclohexanol, cyclohexanone and cyclohexane) with a cumulative yield of ~40%. In contrast catechol favoured hydrogenation, specifically to cis-1,2-dihydroxycyclohexane. It is proposed that cis-isomers are formed from hydrogenation of dihydroxycyclohexenes and high selectivity to cis-1,2-dihydroxycyclohexane can be explained by the enhanced stability of 1,2-dihydroxycyclohex-1-ene relative to other cyclohexene intermediates of catechol, resorcinol or hydroquinone. Trans-isomers are not formed by isomerisation of the equivalent cis-dihydroxycyclohexane but by direct hydrogenation of 2/3/4-hydroxycyclohexanone. The higher selectivity to HDO for resorcinol and hydroquinone may relate to the reactive surface cyclohexenes that have a C=C double bond β-γ to a hydroxyl group aiding hydrogenolysis. Using deuterium instead of hydrogen revealed that each isomer had a unique kinetic isotope effect and that HDO to cyclohexane was dramatically affected. The delay in the production of cyclohexane suggest that deuterium acted as an inhibitor and may have blocked the specific HDO site that results in cyclohexane formation. Carbon deposition was detected by temperature programmed oxidation (TPO) and revealed three surface species.

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Berezuk, Márcio E., Rafael B. Samulewski, Nakédia M. F. Carvalho, Andrea Paesano Jr., Pedro A. Arroyo e Lúcio Cardozo-Filho. "Mononuclear iron(III) piperazine-derived complexes and application in the oxidation of cyclohexane". Kataliz v promyshlennosti 21, n. 3 (17 maggio 2021): 183. http://dx.doi.org/10.18412/1816-0387-2021-3-183.

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Oxygenated products from selective hydrocarbon oxidation have high commercial value as industrial feedstocks. One of the most important industrial processes is the cyclohexane oxidation to produce cyclohexanol and cyclohexanone. These organic substances have special importance in the Nylon manufacture as well as building blocks for a variety of commercially useful products. In this work we present the synthesis and characterization of a new mononuclear piperazine-derived series of iron(III) complexes and their catalytic activity towards cyclohexane oxidation essays. All complexes present octahedral high-spin iron(III) center according to elemental analysis, FTIR, UV-VIS and Mössbauer spectroscopy characterization. The cyclohexane oxidation resulted in cyclohexanol, cyclohexanone and cyclohexyl hydroperoxide as products, with yields up to 39 %. The best results were obtained with the complex (NH4)[Fe(BPPZ)Cl2] (BPPZ: lithium 1,4-bis-(propanoate) piperazine) and with hydrogen peroxide as oxidant. The reactions were carried out at room temperature and atmospheric pressure, which incomes a great advantage over the current industrial process of cyclohexane production.

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Sheng, Xiaoxiao, Qinbo Wang, Zhenhua Xiong e Chuxiong Chen. "Solubilities of adipic acid in binary cyclohexanone + cyclohexanol, cyclohexane + cyclohexanol, and cyclohexane + cyclohexanone solvent mixtures". Fluid Phase Equilibria 415 (maggio 2016): 8–17. http://dx.doi.org/10.1016/j.fluid.2016.01.006.

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Rekkab-Hammoumraoui, Ilhem, e Abderrahim Choukchou-Braham. "Catalytic Properties of Alumina-Supported Ruthenium, Platinum, and Cobalt Nanoparticles towards the Oxidation of Cyclohexane to Cyclohexanol and Cyclohexanone". Bulletin of Chemical Reaction Engineering & Catalysis 13, n. 1 (2 aprile 2018): 24. http://dx.doi.org/10.9767/bcrec.13.1.1226.24-35.

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A series of metal-loaded (Ru, Pt, Co) alumina catalysts were evaluated for the catalytic oxidation of cyclohexane using tertbutylhydroperoxide (TBHP) as oxidant and acetonitrile or acetic acid as solvent. These materials were prepared by the impregnation method and then characterized by Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES), H2 chemisorption, Fourier Transformed Infrared Spectroscopy (FTIR), High-Resolution Transmission Electron Microscopy (HRTEM), and X-ray Diffraction (XRD). All the prepared materials acted as efficient catalysts. Among them, Ru/Al2O3 was found to have the best catalytic activity with enhanced cyclohexane conversion of 36 %, selectivity to cyclohexanol and cyclohexanone of 96 % (57.6 mmol), and cyclohexane turnover frequency (TOF) of 288 h-1. Copyright © 2018 BCREC Group. All rights reservedReceived: 26th May 2017; Revised: 17th July 2017; Accepted: 18th July 2017; Available online: 22nd January 2018; Published regularly: 2nd April 2018How to Cite: Rekkab-Hammoumraoui, I., Choukchou-Braham, A. (2018). Catalytic Properties of Alumina-Supported Ruthenium, Platinum, and Cobalt Nanoparticles towards the Oxidation of Cyclohexane to Cyclohexanol and Cyclohexanone. Bulletin of Chemical Reaction Engineering & Catalysis, 13(1): 24-36 (doi:10.9767/bcrec.13.1.1226.24-35)

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Zhao, Jing, Ming Qiao Zhu, Jia Jing Chen, Yang Yang Yang, Yue Tang, Zhen Yu Cai, Yang Yi Shen e Chao Hong He. "Cyclohexane Oxidation Catalyzed by Au/MxOyAl₂O₃ Using Molecular Oxygen". Advanced Materials Research 233-235 (maggio 2011): 254–59. http://dx.doi.org/10.4028/www.scientific.net/amr.233-235.254.

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Alumina was modified by doping with metal oxide and then used as the support for depositing gold by an impregnation-ammonia washing method to obtain Au/MxOy/Al2O3(M=Co, Zr and Ce) catalysts. These samples were characterized by inductively coupled plasma-atomic emission spectrometry (ICP-AES), transmission electron microscope (TEM) and X-ray diffraction (XRD). The effects of Co3O4content, metal oxide and mixed metal oxides on the catalytic activity for the selective oxidation of cyclohexane to cyclohexanone and cyclohexanol using molecular oxygen as oxidant were studied. The results showed that better catalytic performance was obtained over Au/MxOy/Al2O3catalysts compared with over Au/Al2O3catalysts. 9.69% conversion of cyclohexane and 93.31% selectivity to cyclohexanone, cyclohexanol and cyclohexyl hydroperoxide, with 1.02 ratio of cyclohexanone to cyclohexanol were obtained over the Au/MxOy/Al2O3catalyst at 150 , 1.5 MPa for 3 h. Moreover, according to the recycling test, the catalyst could be reused four times without remarkable loss of activity.

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Lesbani, Aldes, Fatmawati Fatmawati, Risfidian Mohadi, Najma Annuria Fithri e Dedi Rohendi. "Oxidation of Cyclohexane to Cylohexanol and Cyclohexanone Over H₄[a-SiW₁₂O₄₀]/TiO₂ Catalyst". Indonesian Journal of Chemistry 16, n. 2 (13 marzo 2018): 175. http://dx.doi.org/10.22146/ijc.21161.

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Oxidation of cyclohexane to cyclohexanol and cyclohexanone was carried out using H4[a-SiW12O40]/TiO2 as catalyst. In the first experiment, catalyst H4[a-SiW12O40]/TiO2 was synthesized and characterized using FTIR spectroscopy and X-Ray analysis. In the second experiment, catalyst H4[a-SiW12O40]/TiO2 was applied for conversion of cyclohexane. The conversion of cyclohexane was monitored using GC and GCMS. The results showed that H4[a-SiW12O40]/TiO2 was successfully synthesized using 1 g of H4[a-SiW12O40] and 0.5 g of TiO2. The FTIR spectrum showed vibration of H4[a-SiW12O40] appeared at 771-979 cm-1 and TiO2 at 520-680 cm-1. The XRD powder pattern analysis indicated that crystallinity of catalyst still remained after impregnation to form H4[a-SiW12O40]/TiO2. The H4[a-SiW12O40]/TiO2 catalyst was used for oxidation of cyclohexane in heterogeneous system under mild condition at 2 h, 70 °C, 0.038 g catalyst, and 3 mL hydrogen peroxide to give cyclohexanone as major product.

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Yang, Dexin, Tianbin Wu, Chunjun Chen, Weiwei Guo, Huizhen Liu e Buxing Han. "The highly selective aerobic oxidation of cyclohexane to cyclohexanone and cyclohexanol over V2O5@TiO2 under simulated solar light irradiation". Green Chemistry 19, n. 1 (2017): 311–18. http://dx.doi.org/10.1039/c6gc02748b.

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Hwang, Kuo Chu, e Arunachalam Sagadevan. "One-pot room-temperature conversion of cyclohexane to adipic acid by ozone and UV light". Science 346, n. 6216 (18 dicembre 2014): 1495–98. http://dx.doi.org/10.1126/science.1259684.

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Nitric acid oxidation of cyclohexane accounts for ~95% of the worldwide adipic acid production and is also responsible for ~5 to 8% of the annual worldwide anthropogenic emission of the ozone-depleting greenhouse gas nitrous oxide (N2O). Here we report a N2O-free process for adipic acid synthesis. Treatment of neat cyclohexane, cyclohexanol, or cyclohexanone with ozone at room temperature and 1 atmosphere of pressure affords adipic acid as a solid precipitate. Addition of acidic water or exposure to ultraviolet (UV) light irradiation (or a combination of both) dramatically enhances the oxidative conversion of cyclohexane to adipic acid.

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Song, Hua, Hua Lin Song e Zai Shun Jin. "Preparation and Catalytic Performance of Co-Mo/V₂O₅ Composite Catalyst for Selective Oxidation of Cyclohexane". Advanced Materials Research 485 (febbraio 2012): 76–79. http://dx.doi.org/10.4028/www.scientific.net/amr.485.76.

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A new type composite catalyst Co-Mo/V2O5 was prepared by immersion method and characterized by XRD, BET and FT-IR. The effects of Mo mass fraction, immersion time and calcination temperature on catalyst activity for oxidation of cyclohexane were investigated. Co-Mo/V2O5 subjected to immersion with 20% ammonium molybdate solution at room temperature for 1 h and calcination at 600°C exhibited the best performance. Using 0.5 ml of cyclohexane, 3 ml of hydrogen peroxide and 30 mg of catalyst at a reaction temperature of 65°C for 3 h, the cyclohexane conversion was 32.3% and the total selectivity to cyclohexanol and cyclohexanone was 100%.

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Li, Hui, Yuanbin She, Haiyan Fu, Meijuan Cao, Jing Wang e Tao Wang. "Synergistic effect of co-reactant promotes one-step oxidation of cyclohexane into adipic acid catalyzed by manganese porphyrins". Canadian Journal of Chemistry 93, n. 7 (luglio 2015): 696–701. http://dx.doi.org/10.1139/cjc-2014-0515.

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The synergistic effect of cyclohexane and cyclohexanone promoted synthesis of adipic acid catalyzed by [MnIIIT(p-Cl)PP]Cl with cyclohexane and cyclohexanone as co-reactants. The results showed that the conversions of cyclohexane and cyclohexanone were significantly enhanced because of the cyclohexanone synergistic effect, and the higher selectivity to adipic acid was obtained with dioxygen as an oxidant. The studies indicated that the co-oxidation of cyclohexane and cyclohexanone was influenced by the initial molar ratio of cyclohexanone and cyclohexane, catalyst structure, catalyst concentrations, and reaction conditions. The preliminary mechanism of the co-oxidation reaction of cyclohexane and cyclohexanone using [MnIIIT(p-Cl)PP]Cl as the catalyst was proposed.

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Lesbani, Aldes, Menik Setyowati, Risfidian Mohadi e Dedi Rohendi. "Oxidation Of Cyclohexane To Cyclohexanol And Cyclohexanone Using H4[α-SiW12O40]/Zr As Catalyst". Molekul 11, n. 1 (16 maggio 2016): 53. http://dx.doi.org/10.20884/1.jm.2016.11.1.194.

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Synthesis and preparation of polyoxometalate H4[α-SiW12O40].nH2O with Zr as support at various weights of Zr 0.01g; 0.05 g; 0.25 g; 0.5 g; 0.75 g; 1 g and 1.25 g to form H4[α- SiW12O40]/Zr was conducted. The compounds from preparation were characterized using FTIR spectroscopy and crystallinity analysis using X-Ray diffraction. Thus H4[α- SiW12O40]/Zr was applied as catalyst for oxidation of cyclohexane to cyclohexanol and cyclohexanone. Oxidation process was studied through reaction time, hydrogen peroxide amount, temperature, and weight of catalyst. FTIR spectrum of H4[α-SiW12O40]/Zr was appeared at wavenumber 771.53-979.84 cm-1 and Zr at 486.06-1481.33 cm-1. Diffraction pattern of H4[α-SiW12O40]/Zr showed that high crystallinity was identified at 2θ 8o-10o and 28.3o. Based on FTIR spectrum and XRD powder pattern, the optimum preparation of H4[α-SiW12O40]/Zr was obtained using 0.5 g of Zr. The catalytic study of cyclohexane using H4[α-SiW12O40]/Zr at 0.5 g of Zr resulted conversion about 99.73%. Catalyst can convert cyclohexane with the highest conversion then used for further deep catalytic investigation. Optimization of oxidation process resulted optimum reaction time at 2 h, 3 mL of hydrogen peroxide amount, 80 oC of temperature, and 0.038 g of catalyst. The GCMS analysis indicated the oxidation of cyclohexane using H4[α-SiW12O40]/Zr at 0.5 g of Zr formed cyclohexanol and cyclohexanone with selectivity 18.77 and 23.57, respectively.

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Song, Hua, Zai Shun Jin, Qiang Lv e Ming Guan. "Novel and Efficient Co-Mo/V₂O₅ Composite Catalysts for the Selective Oxidation of Cyclohexane". Advanced Materials Research 233-235 (maggio 2011): 949–52. http://dx.doi.org/10.4028/www.scientific.net/amr.233-235.949.

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A new type composite catalyst of V2O5 comprising Co-Mo/V2O5 was prepared by immersion method and characterized by XRD. The characteristic peaks of CoMoO4(2θ=28.51°) and CoMoO3(2θ=18.06 °)are both observed in the XRD patterns of Co-Mo/V2O5(5%, 20%) catalysts. The oxidation of cyclohexane with hydrogen peroxide was used as a probe reaction to investigate the effects of some conditions, such the sort and volume of solvent, catalyst amount, oxidant amount, reaction temperature and time, on reaction. Using 0.5 ml of cyclohexane, 10 ml of acetonitrile, 3 ml of hydrogen peroxide and 0.03 g of catalyst at a reaction temperature of 55°C for 3 h, the cyclohexane conversion was 32.3% and the total selectivity to cyclohexanol and cyclohexanone was 100%.

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Pokutsa, Alexander, Pawel Bloniarz, Orest Fliunt, Yuliya Kubaj, Andriy Zaborovskyi e Tomasz Paczeŝniak. "Sustainable oxidation of cyclohexane catalyzed by a VO(acac)2-oxalic acid tandem: the electrochemical motive of the process efficiency". RSC Advances 10, n. 18 (2020): 10959–71. http://dx.doi.org/10.1039/d0ra00495b.

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Cyclohexane oxidation by H₂O₂ to cyclohexanol, cyclohexanone, and cyclohexylhydroperoxide under mild (40 °C, 1 atm) conditions is significantly enhanced in the system composed of VO(acac)₂ (starting catalyst) and small additives of oxalic acid (process promoter).

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Ichihashi, Yuichi, Shingo Saijo, Masaaki Taniguchi, Keita Taniya e Satoru Nishiyama. "Study of Cyclohexane Photooxidation over Pt-WO₃ Catalysts Mixed with TiO₂ under Visible Light Irradiation". Materials Science Forum 658 (luglio 2010): 149–52. http://dx.doi.org/10.4028/www.scientific.net/msf.658.149.

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The photooxidation of cyclohexane to cyclohexanone, cyclohexanol and CO2 was carried out by visible light irradiation to tungsten oxide photocatalysts. The physical mixing of tungsten oxide and titanium oxide (WO3+TiO2) led to the high photocatalytic activity. It was speculated that the physical mixing of WO3 and TiO2 took place the charge transfer between WO3 and TiO2, and this inhibited the recombination between electrons and holes on the WO3 surface. The platinum loading on WO3 further developed the photocatalytic activity of WO3+TiO2 photocatalyst. Hence, the degree of the recombination between electrons and holes may dominate the photocatalytic activity of cyclohexane oxidation.

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Matias, Inês A. S., A. P. C. Ribeiro, Rui P. Oliveira-Silva, Duarte M. F. Prazeres e Luísa M. D. R. S. Martins. "Gold Nanotriangles as Selective Catalysts for Cyclohexanol and Cyclohexanone Production". Applied Sciences 8, n. 12 (17 dicembre 2018): 2655. http://dx.doi.org/10.3390/app8122655.

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Abstract (sommario):

The search for sustainable catalytic oxidation processes remains a challenge. One process of utmost industrial and economic importance is the selective oxidation of cyclohexane, in the route of nylon-6,6 production, which requires urgent improvement. Herein, Au nanotriangles (Au NTs) were prepared following a three-step (seed preparation, growth and shaping) procedure and applied, for the first time, as catalysts for the selective oxidation of neat cyclohexane to ketone and alcohol (KA) oil (cyclohexanol and cyclohexanone mixture). The Au NTs successfully yield KA oil (up to 14%) under mild conditions (50 °C), using an alternative energy source (microwave irradiation) as reaction promotor.

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25

Siboonruang, Tana, e Karla Negrete. "Reaction Pathways for the Electrochemical Synthesis of KA Oil from Cyclohexane". ECS Meeting Abstracts MA2022-02, n. 64 (9 ottobre 2022): 2387. http://dx.doi.org/10.1149/ma2022-02642387mtgabs.

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Abstract (sommario):

Recent decreases in the cost of electricity from both renewable and non-renewable sources and limitations of fossil fuel resources have bolstered interest in producing commodity chemicals using electrochemistry. Electrosynthesis offers promising alternatives to thermochemical processes, because they do not typically require extreme temperature and pressure. In addition, electric current can be used to replace dangerous reducing and oxidizing agents used in traditional organic chemistry. Electrosynthesis has been demonstrated as a possible pathway for partial oxidation of alkanes, which contain extremely inert C-H bonds. A major challenge in nylon 6,6 manufacturing is cyclohexane conversion to KA oil, a mixture of cyclohexanone and cyclohexanol. In the current industry, this process suffers from low cyclohexane conversion and pressure requirements. Although cyclohexane electrochemical oxidation to KA oil has been demonstrated in literature, the mechanism by which this occurs is still poorly understood. In this work, we demonstrate KA oil production through cyclohexane electrochemical oxidation in organic electrolytes. Using chronoamperometry, we identify the oxygen source (oxygen gas vs. water) for this reaction. In addition, we show that the cathodic counter reaction can influence cyclohexane conversion to KA oil and should be accounted for in mechanistic experiments. Based on literature, side product analysis, and electroanalytical methods, we propose a reaction pathway for electrochemical cyclohexane conversion to KA oil.

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26

Siboonruang, Tana, e Maureen Tang. "Mechanistic Insights into the Electrochemical Oxidation of Cyclohexane". ECS Meeting Abstracts MA2022-02, n. 52 (9 ottobre 2022): 1996. http://dx.doi.org/10.1149/ma2022-02521996mtgabs.

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Abstract (sommario):

The detrimental effects of CO2 emissions from fossil fuels and the decreasing cost of electricity have accelerated interest in electrochemical synthesis. Electro-organic synthesis offers a sustainable and cost-effective pathway for chemical manufacturing. This method has the potential to minimize greenhouse gas emissions, enhance reaction selectivity, and replace hazardous chemical reagents with electric current. Electrochemistry enables alternative mild temperature and pressure pathways to traditional thermochemical reactions. An intermediate step to producing nylon 6,6 is synthesis of KA oil, a mixture of cyclohexanone and cyclohexanol, from cyclohexane. This reaction is limited by low conversion and high pressures. An electrochemical approach can introduce a more selective reaction pathway at more benign conditions. Although electrochemical cyclohexane oxidation to KA oil has been demonstrated in literature, its mechanism remains poorly understood. In this work, we elucidate the mechanism of electrochemical cyclohexane oxidation. We report the oxygen source (water vs. oxygen) and the role of the counter electrode reaction cyclohexane oxidation. Through analysis of side products and electroanalytical methods, we suggest a reaction pathway. In addition, we use chronoamperometry to demonstrate that electrode material affects cyclohexane conversion and recommend the optimal catalyst for this reaction.

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27

Fahy, Kira, Adam Liu, Kelsie Barnard, Valerie Bright, Robert Enright e Patrick Hoggard. "Photooxidation of Cyclohexane by Visible and Near-UV Light Catalyzed by Tetraethylammonium Tetrachloroferrate". Catalysts 8, n. 9 (19 settembre 2018): 403. http://dx.doi.org/10.3390/catal8090403.

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Abstract (sommario):

Tetraethylammonium tetrachloroferrate catalyzes the photooxidation of cyclohexane heterogeneously, exhibiting significant photocatalysis even in the visible portion of the spectrum. The photoproducts, cyclohexanol and cyclohexanone, initially develop at constant rates, implying that the ketone and the alcohol are both primary products. The yield is improved by the inclusion of 1% acetic acid in the cyclohexane. With small amounts of catalyst, the reaction rate increases with the amount of catalyst employed, but then passes through a maximum and decreases, due to increased reflection of the incident light. The reaction rate also passes through a maximum as the percentage of dioxygen above the sample is increased. This behavior is due to quenching by oxygen, which at the same time is a reactant. Under one set of reaction conditions, the photonic efficiency at 365 nm was 0.018 mol/Einstein. Compared to TiO2 as a catalyst, Et4N[FeCl4] generates lower yields at wavelengths below about 380 nm, but higher yields at longer wavelengths. Selectivity for cyclohexanol is considerably greater with Et4N[FeCl4], and oxidation does not proceed past cyclohexanone.

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28

Gao, Su Ling, Tai Xuan Jia e Zi Li Liu. "Catalyzed Oxidation of Cyclohexane over Co-Bi₂(MoO₄)₃ Catalysts". Advanced Materials Research 550-553 (luglio 2012): 354–57. http://dx.doi.org/10.4028/www.scientific.net/amr.550-553.354.

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Abstract (sommario):

The effect of catalyst on the performance of liquid-phase selective oxidation of cyclohexane as probe reaction over Co-Bi2(MoO4)3 prepared by precipitation method was investigated. The catalyst evaluation results show that the optimum catalyst atomic ratio is n(Mo):n(Bi):n(Co)=1.5:1:0.2 with high selecivity under certain conversion. Meanwhile selective oxidation of Bi2(MoO4)3 was slowed down, selecivity of cyclohexanone and cyclohexanol reached 74.1%, 22.2% respectively.The main composition of the catalyst is Bi2(MoO4)3. Co-Bi2(MoO4)3 had new catalyst sites with Bi3+, Mo6+ and Co2+ having a cooperative effects during oxidation of cyclohexane. Under this condition, selecivity of cyclohexanone improved greatly. Micro-structure and essence disciplinarian of Co-Bi2(MoO4)3 were disclosed by XRD and FTIR. This study could provide experimental data for the technical reform of industry equipment.

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29

Wan, Jun, Jing Zhao, Ming Qiao Zhu, Huan Dai e Lei Wang. "Selective Oxidation of Cyclohexane to Cyclohexanone and Cyclohexanol over Au/Co₃O₄ Catalyst". Advanced Materials Research 284-286 (luglio 2011): 806–10. http://dx.doi.org/10.4028/www.scientific.net/amr.284-286.806.

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Abstract (sommario):

Au/Co3O4catalysts were prepared by a co-precipitation method and characterized by inductively coupled plasma-atomic emission spectrometry (ICP-AES), transmission electron microscope (TEM) and X-ray diffraction (XRD). The selective oxidation of cyclohexane to cyclohexanone and cyclohexanol was investigated over Au/Co3O4catalysts using molecular oxygen as oxidant. These catalysts showed higher activities as compared to the pure Co3O4under the same reaction conditions.

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30

Peng, Ling, Chan Liu, Na Li, Wenzhou Zhong, Liqiu Mao, Steven Robert Kirk e Dulin Yin. "Direct cyclohexanone oxime synthesis via oxidation–oximization of cyclohexane with ammonium acetate". Chemical Communications 56, n. 9 (2020): 1436–39. http://dx.doi.org/10.1039/c9cc09840b.

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Abstract (sommario):

One-step preparation of cyclohexanone oxime from cyclohexane and ammonium acetate. 13.6% cyclohexane conversion and 51% cyclohexanone oxime selectivity are achieved. Varieties of different ammonias as readily available starting materials.

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31

Pei, Yinchuan, Qinbo Wang, Xing Gong, Fuqiong Lei e Binwei Shen. "Distribution of cyclohexanol and cyclohexanone between water and cyclohexane". Fluid Phase Equilibria 394 (maggio 2015): 129–39. http://dx.doi.org/10.1016/j.fluid.2015.02.029.

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32

Jin, Mei, Ping Lu e Guo Xian Yu. "Kinetic Study of the Oxidative Dehydrogenation of Cyclohexane over Mg₃(VO₄)₂ Catalyst". Advanced Materials Research 550-553 (luglio 2012): 379–82. http://dx.doi.org/10.4028/www.scientific.net/amr.550-553.379.

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Abstract (sommario):

A Mg3(VO4)2catalyst was synthesized and investigated for the oxidative dehydrogenation of cyclohexane to cyclohexene. Integral measurements were performed to determine the reaction network and products distribution, and differential measurements for kinetic investigations. The kinetic study indicated the oxidative dehydrogenation of cyclohexane to cyclohexene follow a parallel-consecutive network. The power law kinetic model was considered as a rough approximation of the experimental results. The rate constants, which included the activation energies, the pre-exponential factors as well as the orders of cyclohexane and oxygen, were evaluated.

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33

Kirillova, Marina V., Polyana Tomé de Paiva, Wagner A. Carvalho, Dalmo Mandelli e Alexander M. Kirillov. "Mixed-ligand aminoalcohol-dicarboxylate copper(II) coordination polymers as catalysts for the oxidative functionalization of cyclic alkanes and alkenes". Pure and Applied Chemistry 89, n. 1 (1 gennaio 2017): 61–73. http://dx.doi.org/10.1515/pac-2016-1012.

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Abstract (sommario):

AbstractNew copper(II) catalytic systems for the mild oxidative C–H functionalization of cycloalkanes and cycloalkenes were developed, which are based on a series of mixed-ligand aminoalcohol-dicarboxylate coordination polymers, namely [Cu2(μ-dmea)2(μ-nda)(H2O)2]n·2nH2O (1), [Cu2(μ-Hmdea)2(μ-nda)]n·2nH2O (2), and [Cu2(μ-Hbdea)2(μ-nda)]n·2nH2O (3) that bear slightly different dicopper(II) aminoalcoholate cores, as well as on a structurally distinct dicopper(II) [Cu2(H4etda)2(μ-nda)]·nda·4H2O (4) derivative [abbreviations: H2nda, 2,6-naphthalenedicarboxylic acid; Hdmea, N,N′-dimethylethanolamine; H2mdea, N-methyldiethanolamine; H2bdea, N-butyldiethanolamine; H4etda, N,N,N′,N′-tetrakis(2-hydroxyethyl)ethylenediamine]. Compounds 1–4 act as homogeneous catalysts in the three types of model catalytic reactions that proceed in aqueous acetonitrile medium under mild conditions (50–60°C): (i) the oxidation of cyclohexane by hydrogen peroxide to cyclohexyl hydroperoxide, cyclohexanol, and cyclohexanone, (ii) the oxidation of cycloalkenes (cyclohexene, cyclooctene) by hydrogen peroxide to a mixture of different oxidation products, and (iii) the single-pot hydrocarboxylation of cycloalkanes (cyclopentane, cyclohexane, cycloheptane, cyclooctane) by carbon monoxide, water, and a peroxodisulfate oxidant into the corresponding cycloalkanecarboxylic acids. The catalyst and substrate scope as well as some mechanistic features were investigated; the highest catalytic activity of 1–4 was observed in the hydrocarboxylation of cycloalkanes, allowing to achieve up to 50% total product yields (based on substrate).

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34

Roy Barman, Tannistha, Manas Sutradhar, Elisabete C. B. A. Alegria, Maria de Fátima C. Guedes da Silva e Armando J. L. Pombeiro. "Fe(III) Complexes in Cyclohexane Oxidation: Comparison of Catalytic Activities under Different Energy Stimuli". Catalysts 10, n. 10 (13 ottobre 2020): 1175. http://dx.doi.org/10.3390/catal10101175.

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Abstract (sommario):

In this study, the mononuclear Fe(III) complex [Fe(HL)(NO3)(H2O)2]NO3 (1) derived from Nʹ-acetylpyrazine-2-carbohydrazide (H2L) was synthesized and characterized by several physicochemical methods, e.g., elemental analysis, infrared (IR) spectroscopy, electrospray ionization mass spectrometry (ESI-MS), and single crystal X-ray diffraction analysis. The catalytic performances of 1 and the previously reported complexes [Fe(HL)Cl2] (2) and [Fe(HL)Cl(μ-OMe)]2 (3) towards the peroxidative oxidation of cyclohexane under three different energy stimuli (microwave irradiation, ultrasound, and conventional heating) were compared. 1-3 displayed homogeneous catalytic activity, leading to the formation of cyclohexanol and cyclohexanone as final products, with a high selectivity for the alcohol (up to 95%). Complex 1 exhibited the highest catalytic activity, with a total product yield of 38% (cyclohexanol + cyclohexanone) under optimized microwave-assisted conditions.

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35

Guo, Can-Cheng, Xiao-Qin Liu, Qiang Liu, Yang Liu, Ming-Fu Chu e Wei-Ying Lin. "First industrial-scale biomimetic oxidation of hydrocarbon with air over metalloporphyrins as cytochrome P-450 monooxygenase model and its mechanistic studies". Journal of Porphyrins and Phthalocyanines 13, n. 12 (dicembre 2009): 1250–54. http://dx.doi.org/10.1142/s1088424609001613.

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Abstract (sommario):

A novel industrial-scale trial for cyclohexane oxidation with air over metalloporphyrins as cytochrome P-450 monooxygenase model was reported. Upon addition of extremely low concentrations (1–5 ppm) of simple cobalt porphyrin to the commercial cyclohexane oxidation system, and decrease of the reaction temperature and pressure about 20 °C and 0.4 MPa respectively, the conversion rate of the cyclohexane oxidation increased from 4.8% to 7.1%, the yield of cyclohexanone raised from 77% to 87%, and a 70,000-ton cyclohexanone equipment set yielded an output of 125,000 tons cyclohexanone. Furthermore, a novel biological-chemical-cycle coupling mechanism was proposed to rationalize the aerobic oxidations of hydrocarbons catalyzed by the metalloporphyrins.

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36

Kim, Sin Young, Jaehoon Choe e Kwang Ho Song. "(Liquid + Liquid) Equilibria of (Cyclohexane + Dimethyl Sulfoxide + Cyclohexanone) and (Cyclohexane + Dimethyl Sulfoxide + Cyclohexanol) atT= 303.2 K". Journal of Chemical & Engineering Data 55, n. 3 (11 marzo 2010): 1109–12. http://dx.doi.org/10.1021/je900549r.

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37

Yu, Ximeng, Zhongquan Shen, Qing Sun, Nianlong Qian, Chao Zhou e Jizhong Chen. "Solubilities of Adipic Acid in Cyclohexanol + Cyclohexanone Mixtures and Cyclohexanone + Cyclohexane Mixtures". Journal of Chemical & Engineering Data 61, n. 3 (4 febbraio 2016): 1236–45. http://dx.doi.org/10.1021/acs.jced.5b00880.

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38

Saleh, M. S. A., A. Aouissi, A. A. Al-Suhybani e A. M. Al-Mayouf. "Fabrication of Carbon Graphite-supported Pt–SiW12O40 Catalysts Effect of the Pt Loading on the Electrooxidation of Cyclohexane". Journal of New Materials for Electrochemical Systems 17, n. 2 (8 aprile 2014): 049–54. http://dx.doi.org/10.14447/jnmes.v17i2.423.

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Abstract (sommario):

H4SiW12O40 (abbreviated as SiW) and Pt supported on carbon graphite (CG) with different Pt/SiW ratios were prepared and characterized by FTIR, XRD, ICP-OES, polarography, and TEM. The prepared catalysts were then after successfully attached onto glassy carbon electrodes by using polyvinylidene difluoride (PVDF) as binder. The resulting electrocatalysts were characterized by cyclic voltammetry (CV) and tested for the electrooxidation of cyclohexane. It has been found that the addition of SiW to the catalyst increased the dispersion of the Pt particles. The results of the electrocatalytic tests showed that cyclohexanone, cyclohexanol, and cyclohexyl hydroperoxide are formed as major products of the reaction. Higher Pt loadings promoted cyclohexanone production.

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39

Hong, Yun, Yanxiong Fang, Dalei Sun e Xiantai Zhou. "Ionic liquids modified cobalt/ZSM-5 as a highly efficient catalyst for enhancing the selectivity towards KA oil in the aerobic oxidation of cyclohexane". Open Chemistry 17, n. 1 (21 agosto 2019): 639–46. http://dx.doi.org/10.1515/chem-2019-0068.

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Abstract (sommario):

AbstractThe industrial oxidation of cyclohexane is currently performed with very low conversion level, i.e. 4-6% conversion and poor selectivity for cyclohexanone and cyclohexanol (K-A oil), i.e.70-85%, at above 150oC reaction temperature and above 10atm reaction pressure using molecular oxygen oxidant and homogeneous catalyst. Several disadvantages are, however, associated with the process, such as, complex catalyst-product separation, high power input, and low safe operation. Therefore, the oxidation of cyclohexane using heterogeneous catalyst oxygen oxidant from air at mild conditions has received particular attention. Aerobic oxidation of cyclohexane over ionic liquids modified cobalt/ZSM-5 (IL-Co/ZSM-5) in absence of solvents was developed in this article. The prepared catalysts were characterized by XRD, FT-IR, N2 adsorption-desorption, SEM, TEM and XPS analyses. The influence of reaction parameters on the oxidation of cyclohexane was researched, such as the various catalysts, reaction temperature, reaction time, and the reaction pressure, on the process. Highly selective synthesis of KA oil was performed by aerobic oxidation of cyclohexane using ionic liquids modified cobalt/ZSM-5 (IL-Co/ZSM-5) as the catalyst in absence of solvents for the first time. A selectivity of up to 93.6% of KA oil with 9.2% conversion of cyclohexane was produced at 150℃ and 1.5 MPa after 3 h, with about 0.1 mol cyclohexane, C7mimHSO4-Co/ZSM-5 catalyst equal to 6.0 wt%, respectively. The induction period of oxidation was greatly shortened when the ionic liquid was supported on ZSM-5. The catalyst was easy to centrifuge and was reused after five cycles. It was found that both the characterization and performance of the catalysts revealed that both the presence of oxygen vacancies with incorporation of Co ions into the framework of ZSM-5 and the introduction of C7mimHSO4 into the ZSM-5 leads to the both satisfactory selectivity and robust stability of the C7mimHSO4-Co/ZSM-5 heterogeneous catalyst.

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40

Rydel-Ciszek, Katarzyna, Tomasz Pacześniak, Paweł Chmielarz e Andrzej Sobkowiak. "Bio-Inspired Iron Pentadentate Complexes as Dioxygen Activators in the Oxidation of Cyclohexene and Limonene". Molecules 28, n. 5 (28 febbraio 2023): 2240. http://dx.doi.org/10.3390/molecules28052240.

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Abstract (sommario):

The use of dioxygen as an oxidant in fine chemicals production is an emerging problem in chemistry for environmental and economical reasons. In acetonitrile, the [(N4Py)FeII]2+ complex, [N4Py—N,N-bis(2-pyridylmethyl)-N-(bis-2-pyridylmethyl)amine] in the presence of the substrate activates dioxygen for the oxygenation of cyclohexene and limonene. Cyclohexane is oxidized mainly to 2-cyclohexen-1-one, and 2-cyclohexen-1-ol, cyclohexene oxide is formed in much smaller amounts. Limonene gives as the main products limonene oxide, carvone, and carveol. Perillaldehyde and perillyl alcohol are also present in the products but to a lesser extent. The investigated system is twice as efficient as the [(bpy)2FeII]2+/O2/cyclohexene system and comparable to the [(bpy)2MnII]2+/O2/limonene system. Using cyclic voltammetry, it has been shown that, when the catalyst, dioxgen, and substrate are present simultaneously in the reaction mixture, the iron(IV) oxo adduct [(N4Py)FeIV=O]2+ is formed, which is the oxidative species. This observation is supported by DFT calculations.

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41

Steyer, Frank, e Kai Sundmacher. "VLE and LLE Data for the System Cyclohexane + Cyclohexene + Water + Cyclohexanol". Journal of Chemical & Engineering Data 49, n. 6 (novembre 2004): 1675–81. http://dx.doi.org/10.1021/je049902w.

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42

Vaiano, Vincenzo, e Diana Sannino. "UV Light Driven Selective Oxidation of Cyclohexane in Gaseous Phase Using Mo-Functionalized Zeolites". Surfaces 2, n. 4 (9 dicembre 2019): 546–59. http://dx.doi.org/10.3390/surfaces2040040.

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Abstract (sommario):

Heterogeneous photocatalysis in the gas phase has been applied as a promising technique for organic syntheses in mild conditions. Modified zeolites have been used under UV irradiation as novel photocatalysts. In this study, we preliminarily investigated the photoxidation of cyclohexane on ferrierite and MoOx-functionalized ferrierite in a gas–solid continuous flow reactor. In the presence of UV light, MoOx-functionalized ferrierite showed the formation of benzene and cyclohexene as reaction products, indicating the occurrence of photocatalysed cyclohexane oxydehydrogenation. By contrast, unmodified ammonium ferrierite exhibited relevant activity for total oxidation of cyclohexane to carbon dioxide and water. The influence of Mo loading on cyclohexane conversion and products selectivity was evaluated.

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43

Henríquez, Adolfo, Héctor D. Mansilla, Azael Martínez-de la Cruz, Lorena Cornejo-Ponce, Eduardo Schott e David Contreras. "Selective Oxofunctionalization of Cyclohexene over Titanium Dioxide-Based and Bismuth Oxyhalide Photocatalysts by Visible Light Irradiation". Catalysts 10, n. 12 (10 dicembre 2020): 1448. http://dx.doi.org/10.3390/catal10121448.

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Abstract (sommario):

Photocatalysis driven under visible light allows us to carry out hydrocarbon oxofunctionalization under ambient conditions, using molecular oxygen as a sacrificial reagent, with the absence of hazardous subproducts and the potential use of the Sun as a clean and low-cost source of light. In this work, eight materials—five based on titanium dioxide and three based on bismuth oxyhalides—were used as photocatalysts in the selective oxofunctionalization of cyclohexene. The cyclohexane oxofunctionalization reactions were performed inside of a homemade photoreactor equipped with a 400 W metal halide lamp and injected air as a source of molecular oxygen. In all assayed systems, the main oxygenated products, identified by mass spectrometry, were 1,2-epoxycyclohexane, 2-cyclohexen-1-ol, and 2-cyclohexen-1-one. Titanium dioxide-based materials exhibited higher selectivities for 1,2-epoxycyclohexane than bismuth oxyhalide-based materials. In addition to this, titanium dioxide doped with iron exhibited the best selectivity for 1,2-epoxycyclohexane, demonstrating that iron plays a relevant role in the cyclohexene epoxidation process.

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44

Henríquez, Adolfo, Romina Romero, Lorena Cornejo-Ponce, Claudio Salazar, Juan Díaz, Victoria Melín, Héctor D. Mansilla, Gina Pecchi e David Contreras. "Selective Oxofunctionalization of Cyclohexane and Benzyl Alcohol over BiOI/TiO2 Heterojunction". Catalysts 12, n. 3 (11 marzo 2022): 318. http://dx.doi.org/10.3390/catal12030318.

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Abstract (sommario):

Heterogeneous photocatalysis under visible light irradiation allows performing of selective oxofunctionalization of hydrocarbons at ambient temperature and pressure, using molecular oxygen as a sacrificial reagent and potential use of sunlight as a sustainable and low-cost energy source. In the present work, a photocatalytic material based on heterojunction of titanium dioxide and bismuth oxyiodide was used as photocatalyst on selective oxofunctionalization of cyclohexane and benzyl alcohol. The selective oxidation reactions were performed in a homemade photoreactor equipped with a metal halide lamp and injected air as a source of molecular oxygen. The identified oxidized products obtained from oxofunctionalization of cyclohexane were cyclohexanol and cyclohexanone. On the other hand, the product obtained from oxofunctionalization of benzyl alcohol was benzaldehyde. The yield obtained with BiOI/TiO2 photocatalysts was higher than that obtained with pure bismuth oxyiodide. The higher performance of this material with respect to pure BiOI was attributed to its higher specific area.

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45

Hong, Yuechao, Jie Peng, Zhichao Sun, Zhiquan Yu, Anjie Wang, Yao Wang, Ying-Ya Liu, Fen Xu e Li-Xian Sun. "Transition Metal Oxodiperoxo Complex Modified Metal-Organic Frameworks as Catalysts for the Selective Oxidation of Cyclohexane". Materials 13, n. 4 (12 febbraio 2020): 829. http://dx.doi.org/10.3390/ma13040829.

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Abstract (sommario):

In this work, a series of modified metal-organic frameworks (MOFs) have been prepared by pre- and post-treatment with transition metal oxodiperoxo complexes (MoO(O2)2, WO(O2)2, and KVO(O2)2). The obtained materials are characterized by XRD, FTIR, SEM, TEM, inductively coupled plasma atomic emission spectrometry (ICP-AES), and X-ray photoelectron spectroscopy (XPS), as well as by N2 adsorption/desorption measurement. The characterization results show that transition metal oxodiperoxo complexes are uniformly incorporated into the MOF materials without changing the basic structures. The performance of cyclohexane oxidation on metal oxodiperoxo complex modified MOFs are evaluated. UiO-67-KVO(O2)2 shows the best performance for cyclohexane oxidation, with 78% selectivity to KA oil (KA oil refers to a cyclohexanol and cyclohexanone mixture) at 9.4% conversion. The KA selectivity is found to depend on reaction time, while hot-filtration experiments indicates that the catalytic process is heterogeneous with no leaching of metal species.

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46

Dietz, Wibke, Yvonne Schwerdtfeger, Uwe Klingebiel e Mathias Noltemeyer. "Bis(1-cyclohexen-3-on-1-oxy)silane, Silyl-enole von β-Ketonen/ Bis (1-cyclohexene-3-on-1-oxy)silanes, Silyl-enoles of β -Ketones". Zeitschrift für Naturforschung B 62, n. 11 (1 novembre 2007): 1371–76. http://dx.doi.org/10.1515/znb-2007-1104.

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Abstract (sommario):

5,5-Dimethylcyclohexane-1,3-dione (dimedone) and cyclohexane-1,3-dione react with Cl2Si(CMe3)2 in the presence of triethylamine to give the bis(1-cyclohexene-3-on-1-oxy)dit butylsilanes 2 and 3. Using dimedone and Cl2SiMe2, the analogous dimethylsilane 1 is obtained. A 1,4-Michael-Addition occurs using cyclohexane-1,3-dione in the reaction with Cl2SiMe2 to give a spirocyclic diketone (4). The reaction of cyclohexane-1,3-dione with lithium-diisopropylamide and F3SiCMe3 leads to the formation of a salt [iPr2NH2]2HF[C6H7O2]2, 5. The crystal structures of 2 - 5 were determined.

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47

Sekar, P. Raja, R. Venkateswarlu e Kalluru S. Reddy. "Excess volumes, isentropic compressibilities, and viscosities of binary mixtures containing cyclohexene". Canadian Journal of Chemistry 68, n. 2 (1 febbraio 1990): 363–68. http://dx.doi.org/10.1139/v90-054.

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Abstract (sommario):

Excess volumes, excess isentropic compressibilities, and excess viscosities have been reported for the binary liquid mixtures of cyclohexene with n-hexane, cyclohexane, benzene, trichloromethane, tetrachloromethane, and 1,4-dioxane at 303.15 K. VE results are negative for mixtures of cyclohexene with n-hexane and tetrachloromethane and are positive for the remaining systems. [Formula: see text] values are negative for mixtures of cyclohexene with n-hexane and positive for all other systems. The data of Δ ln η are positive for cyclohexene with cyclohexane and tetrachloromethane, and negative for the remaining systems. Prigogine–Patterson–Flory equation of state theory has been applied to predict excess volumes and excess enthalpies, and the viscosity relations proposed by Bloomfield are used to calculate free energy and free volume contributions to excess viscosity. Keywords: excess volumes, excess isentropic compressibilities, excess viscosities.

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48

Mkhondwane, Siphumelele Thandokwazi, e Viswanadha Srirama Rajasekhar Pullabhotla. "Highly Selective pH-Dependent Ozonation of Cyclohexane over Mn/γ-Al2O3 Catalysts at Ambient Reaction Conditions". Catalysts 9, n. 11 (15 novembre 2019): 958. http://dx.doi.org/10.3390/catal9110958.

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Abstract (sommario):

The selective oxidation of cyclohexane to a mixture of cyclohexanol and cyclohexanone (KA oil) is one of the imperative reactions in industrial processes. In this study, the catalytic performance of manganese-supported gamma alumina (Mn/γ-Al2O3) catalysts is investigated in the selective oxidation of cyclohexane at ambient conditions using ozone. The catalysts were prepared by the wet impregnation method, and their physio-chemical properties were studied by Fourier Transform Infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) spectroscopy, Scanning Electron Microscopy-Energy Dispersive X-ray spectroscopy (SEM-EDX), Transmission Electron Microscopy (TEM), Inductively Coupled Plasma (ICP) spectroscopy, and Brunauer Emmett and Teller (BET). The reaction conditions were optimised considering various parameters such as reaction time, pH, and various percentages of the manganese supported in gamma alumina. The oxidation of cyclohexane was conducted in an impinger reactor unit at pH 3, 7, and 11 for 1 h of ozonation time. The aliquots were collected after 30 min and 1 h of ozonation time and analysed with GC-MS and FT-IR spectroscopy. The 2.5% Mn/γ-Al2O3 catalyst exhibited a significantly enhanced catalytic performance at pH 3 and 7 with a percentage conversion of 9% and 15% at pH 3 and 7, respectively, after 30 min of ozonation time. However, after 1 h of ozonation time, the percentage conversions were increased to 23% and 29% at pH 3 and 7, respectively. At pH 11, 5% Mn/γ-Al2O3 exhibit high catalytic performance with a percentage conversion of 19% and 31% after 30 minutes and 1 h of ozonation time, respectively. The percentage selectivity obtained is 100% toward KA oil and/or cyclohexanone depending on pH and reaction time.

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49

Cai, Zhen Yu, Ming Qiao Zhu, Yue Tang, Yi Liu, Huan Dai, Xin Zhi Chen e Chao Hong He. "Carbon-Supported Gold Catalyst Modified by Doping with Ag for Cyclohexene Oxidation". Advanced Materials Research 236-238 (maggio 2011): 3046–50. http://dx.doi.org/10.4028/www.scientific.net/amr.236-238.3046.

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Carbon-supported gold catalysts Au/C were prepared by an impregnation-reduction method and modified by AgNO3to obtain bi-metallic catalysts Au-Ag/C, which were characterized by X-ray-diffraction (XRD) and Transmission Electron Microscope (TEM). Their catalytic performance was tested in the oxidation of cyclohexene in an autoclave without any solvent. The results showed that Ag doping can significantly enhance the catalytic performance of carbon-supported gold catalyst. Au(1.0 wt.%)-Ag(1.0 wt.%)/C has been found to be an efficient catalyst for the cyclohexene oxidation with a conversion of 27.6% at 80 °C and 0.4 MPa for 12 h while selectivity for ∑C6products (including cyclohexene oxide, 2-cyclohexene-1-ol, 2-cyclohexene-1-one and cyclohexane-1,2-diol) exceeding 88.9%, especially the selectivity of cyclohexane-1,2-diol up to 47.6%. Moreover, the effects of Au, Ag content on catalytic performance were also reported.

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50

Tiago, Gonçalo, Ana Ribeiro, M. C. Guedes da Silva, Kamran Mahmudov, Luís Branco e Armando Pombeiro. "Copper(II) Complexes of Arylhydrazone of 1H-Indene-1,3(2H)-dione as Catalysts for the Oxidation of Cyclohexane in Ionic Liquids". Catalysts 8, n. 12 (7 dicembre 2018): 636. http://dx.doi.org/10.3390/catal8120636.

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The copper(II) complexes [CuL(H2O)2]∙H2O (1) and [CuL(dea)] (2) [L = 2-(2-(1,3-dioxo-1H-inden-2(3H)-ylidene)hydrazinyl)benzenesulfonate, dea = diethanolamine] were applied as catalysts in the peroxidative (with tert-butyl-hydroperoxide or hydrogen peroxide) conversion of cyclohexane to cyclohexanol and cyclohexanone, either in acetonitrile or in any of the ionic liquids [bmim][NTf2] and [hmim][NTf2] [bmim = 1-butyl-3-methylimidazolium, hmim = 1-hexyl-3-methylimidazolium, NTf2 = bis(trifluoromethanesulfonyl) imide]. Tert-butyl-hydroperoxide led to better product yields, as compared to H2O2, with a selectivity directed towards cyclohexanone. The ILs showed a better performance than the conventional solvent for the copper complex 1. No catalytic activity was observed for 2 in the presence of an IL.

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