Zeitschriftenartikel: „Green chemical reaction“

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Nagieva, I. T., N. I. Ali-zadeh und T. M. Nagiev. „GAS-PHASE OXIDATION OF 2-PICOLINE BY “GREEN OXIDIZERS” H2O2 AND N2O“. Azerbaijan Chemical Journal, Nr. 4 (14.11.2023): 13–20. http://dx.doi.org/10.32737/0005-2531-2023-4-13-20.

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This communication presents the results of studies of coherently synchronized reactions of 2-picoline oxidation with hydrogen peroxide and nitrous oxide (I) in the gas phase. Optimal conditions for obtaining target products in these reactions are revealed. The influence of the process parameters on the value of the determinant in the reactions: dealcodimerization of 2-picoline with hydrogen peroxide and dimerization of 2-picoline with nitrous oxide (I) is shown. Calculated in the reaction of deal-codimerization of 2-picoline with hydrogen peroxide, the determinant of chemical conjugation has a value of D = 0.17 under optimal conditions, which indicates the induced character of dealcodimerization of 2-picoline. Based on this value, a quantitative assessment of the influence of the primary reaction (decomposition of hydrogen peroxide) on the secondary one (dealcodimerization of 2-picoline) was given. In the reaction of dimerization of 2-picoline with nitrous oxide (I), the chemical conjugation determinant has, under optimal conditions, a value of D = 0.54, which, according to the chemical interference scale, is in the region of chemical conjugation, when the primary reaction (the decomposition of nitrous oxide (I)) accelerates the secondary reaction (dimerization of 2-picoline)

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Sahoo, Tejaswini, Jagannath Panda, Jnanaranjan Sahu, Dayananda Sarangi, Sunil K. Sahoo, Braja B. Nanda und Rojalin Sahu. „Green Solvent: Green Shadow on Chemical Synthesis“. Current Organic Synthesis 17, Nr. 6 (25.09.2020): 426–39. http://dx.doi.org/10.2174/1570179417666200506102535.

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The natural beauty and purity of our planet has been contaminated deeply due to human selfish activities such as pollution, improper waste management, and various industrial and commercial discharges of untreated toxic by-products into the lap of nature. The collective impact of these hazardous suspensions into the natural habitat is very deadly. Challenges due to human activity on the environment have become ubiquitous. The chemical industry has a major role in human evolution and, predictably, opened gates of increased risk of pollution if the production is not done sustainably. In these circumstances, the notion of Green Chemistry has been identified as the efficient medium of synthesis of chemicals and procedures to eradicate the toxic production of harmful substances. Principles of Green Chemistry guide the scientist in their hunt towards chemical synthesis which requires the use of solvents. These solvents contaminate our air, water, land and surrounding due to its toxic properties. Even though sufficient precautions are taken for proper disposal of these solvents but it is difficult to be recycled. In order to preserve our future and coming generation from the adverse impacts associated with solvents it is very important to find alternative of this which will be easy to use, reusable and also eco-friendly. Solvents are used daily in various industrial processes as reaction medium, as diluters, and in separation procedures. As reaction medium, the role of solvent is to bring catalysts and reactants together and to release heat thus affecting activity and selectivity. The proper selection of the solvent considering its biological, physical and chemical properties is very necessary for product separation, environmental, safety handling and economic factors. Green solvents are the boon in this context. They are not only environmentally benign but also cost effective. The biggest challenge faced by the chemists is adaptation of methods and selection of solvents during chemical synthesis which will give negligible waste product and will remain human and nature friendly. During designing compounds for a particular reaction it is difficult to give assurance regarding the toxicity and biodegradability of the method. Chemists are still far away from predicting the various chemical and biological effects of the compounds on the back of the envelope. To achieve that point is formidable task but it will definitely act as inspiration for the coming generation of chemists. The green solvents are undoubtedly a far better approach to eliminate the negative impacts and aftermath of any chemical synthesis on the environment. Our study in this review covers an overview of green solvents, their role in safer chemical synthesis with reference to some of the important green solvents and their detail summarization.

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Igarashi, Akira. „Catalytic Reaction Engineering toward Green Chemical Processes“. JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 38, Nr. 10 (2005): 779–84. http://dx.doi.org/10.1252/jcej.38.779.

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De Martino, M. Teresa, Loai K. E. A. Abdelmohsen, Floris P. J. T. Rutjes und Jan C. M. van Hest. „Nanoreactors for green catalysis“. Beilstein Journal of Organic Chemistry 14 (29.03.2018): 716–33. http://dx.doi.org/10.3762/bjoc.14.61.

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Sustainable and environmentally benign production are key drivers for developments in the chemical industrial sector, as protecting our planet has become a significant element that should be considered for every industrial breakthrough or technological advancement. As a result, the concept of green chemistry has been recently defined to guide chemists towards minimizing any harmful outcome of chemical processes in either industry or research. Towards greener reactions, scientists have developed various approaches in order to decrease environmental risks while attaining chemical sustainability and elegancy. Utilizing catalytic nanoreactors for greener reactions, for facilitating multistep synthetic pathways in one-pot procedures, is imperative with far-reaching implications in the field. This review is focused on the applications of some of the most used nanoreactors in catalysis, namely: (polymer) vesicles, micelles, dendrimers and nanogels. The ability and efficiency of catalytic nanoreactors to carry out organic reactions in water, to perform cascade reaction and their ability to be recycled will be discussed.

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Prajapati, Pintu, Avani Sheth, Dhaval M. Patel, Advaita Patel und Priti Mehta. „Sonochemistry: Non-Classical Way of Synthesis“. Journal of Drug Delivery and Therapeutics 9, Nr. 6-s (15.12.2019): 229–32. http://dx.doi.org/10.22270/jddt.v9i6-s.3691.

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This review presents the detailed picture of current knowledge on ultrasound assisted chemical reactions and its green approach in chemical synthesis. This article illustrates the theoretical background and details about ultrasound, its mechanism (cavitation, the driving force) in chemical synthesis, types of reactions with different systems and its utility. All the reported applications have shown that Sonochemistry, ultrasound assisted chemical reaction is a green and economical viable approach for drug, impurity or chemical intermediate synthesis. Keywords: Cavitation, Sonocatalysis, Sonochemistry Ultrasound

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Day, Daniel M., Thomas J. Farmer, Joe Granelli, Janice H. Lofthouse, Julie Lynch, Con R. McElroy, James Sherwood, Seishi Shimizu und James H. Clark. „Reaction Optimization for Greener Chemistry with a Comprehensive Spreadsheet Tool“. Molecules 27, Nr. 23 (02.12.2022): 8427. http://dx.doi.org/10.3390/molecules27238427.

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Green chemistry places an emphasis on safer chemicals, waste reduction, and efficiency. Processes should be optimized with green chemistry at the forefront of decision making, embedded into research at the earliest stage. To assist in this endeavor, we present a spreadsheet that can be used to interpret reaction kinetics via Variable Time Normalization Analysis (VTNA), understand solvent effects with linear solvation energy relationships (LSER), and calculate solvent greenness. With this information, new reaction conditions can be explored in silico, calculating product conversions and green chemistry metrics prior to experiments. The application of this tool was validated with literature case studies. Reaction performance was predicted and then confirmed experimentally for examples of aza-Michael addition, Michael addition, and an amidation. The combined analytical package presented herein permits a thorough examination of chemical reactions, so that the variables that control reaction chemistry can be understood, optimized, and made greener for research and education purposes.

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Li, Yanlin, Shenghua Chen, Wenyuan Duan, Yanli Nan, Donghai Ding und Guoqing Xiao. „Research progress of vanadium pentoxide photocatalytic materials“. RSC Advances 13, Nr. 33 (2023): 22945–57. http://dx.doi.org/10.1039/d3ra03648k.

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Daglia, M., A. Papetti und G. Gazzani. „Green and roasted coffee antiradical activity stability in chemical systems“. Czech Journal of Food Sciences 22, SI - Chem. Reactions in Foods V (01.01.2004): S191—S194. http://dx.doi.org/10.17221/10658-cjfs.

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The stability to storage at different temperature and oxygen exposure of green and roasted coffee either as coffee beans or as ground coffee antiradical activity, was evaluated. The results showed that the coffee solution antihydroxyl radical activity was constant, independently from the coffee species, from the roasting process, and moreover from the type of storage conditions, suggesting that temperature and oxygen exposure did not affect this antiradical activity. With regard to antiperoxyl radical activity, all green coffee solutions showed remarkable and stable activity. Conversely, the roasted coffee beans and roasted and ground coffee antiperoxyl radical activity started to increase after three month of storage, suggesting that Maillard reaction products affect the stability of such antiradical property.

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Domènech, Xavier, José A. Ayllón, José Peral und Joan Rieradevall. „How Green Is a Chemical Reaction? Application of LCA to Green Chemistry“. Environmental Science & Technology 36, Nr. 24 (Dezember 2002): 5517–20. http://dx.doi.org/10.1021/es020001m.

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Cunningham, Michael F. „Green Macromolecular Reaction Engineering“. Macromolecular Reaction Engineering 16, Nr. 3 (Juni 2022): 2200033. http://dx.doi.org/10.1002/mren.202200033.

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Suthar, Madhuri J., Jasmin H. Kumbhani, Keyur D. Bhatt, Prakashbhai V. Bishnoi und Parimal Chatrabhuji. „Ultrasound-Assisted Synthesis and Characterization of 5-Carbonitrile-Functionalized tetrahydropyrimidine Derivatives with Evaluation of Their Antimicrobial Activity“. Oriental Journal Of Chemistry 40, Nr. 1 (24.02.2024): 281–87. http://dx.doi.org/10.13005/ojc/400134.

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The green synthesis approach employs ultrasound waves as an effective and environmentally friendly strategy to catalyze chemical reactions. Within this framework, carbonitrile-bearing tetrahydropyrimidine derivatives were successfully synthesized. This involved the reaction of malononitrile, urea or thiourea, and variously substituted aldehydes in the presence of morpholine as a catalyst, conducted in aqueous conditions under ultrasonic irradiation. Notably, this method resulted in elevated reaction yields and significantly reduced reaction times when compared to conventional approaches. The synthesized compounds underwent comprehensive characterization using various spectroscopic techniques, including UV-Vis, 1H NMR, 13C NMR, and mass spectrometry. This innovative process aligns with the principles of green chemistry, emphasizing efficiency, sustainability, and the reduction of environmental impact in chemical synthesis.

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Rusling, James F. „Green synthesis via electrolysis in microemulsions“. Pure and Applied Chemistry 73, Nr. 12 (01.01.2001): 1895–905. http://dx.doi.org/10.1351/pac200173121895.

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Electrolysis in microemulsions is a promising approach for environmentally friendly chemical synthetic methods of the future. Employing microemulsions instead of organic solvents for electrosynthesis has the advantages of lower toxicity and cost, high dissolving power for reactants and mediators of unlike solubility, enhancement of reaction rates by controlling the reduction potentials of mediators, possible reaction pathway control, and recycling of microemulsion components. This paper reviews recent progress in using microemulsions for direct and mediated electrosynthesis, including formation of carboncarbon bonds. Rates of mediated reactions can be controlled by manipulating microemulsion composition. Examples are presented, in which reaction pathways of direct and mediated electrolyses can be controlled with microemulsions to give desired products in high yields. Such control has been demonstrated with dissolved and surface-bound mediators. For a covalently linked scaffold of poly(l-lysine) and cobalt corrin vitamin B12 hexacarboxylate attached to graphite, catalytic turnover rate for reduction of 1,2-dibromocylcohexane was optimized by optimizing microemulsion composition.

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Feng, Tao, und Hao Li. „Functional Catalyst Molecular Sieves in Green Chemical Applications“. Energy Science & Policy 1, Nr. 2 (30.12.2023): 1–10. http://dx.doi.org/10.61187/esp.v1i2.51.

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With the development of green chemical industry and the continuous improvement of environmental awareness, the application of various catalysts in environmental protection has been widely concerned. As a green catalyst, molecular sieve catalyst has superior environmental performance, which is mainly reflected in its ability to improve the selectivity of reaction products, can be reused, good thermal stability and strong adaptability. This paper mainly introduces the types, development history, synthesis technology and application of zeolite catalysts, due to the development of science and technology, a large number of new synthetic zeolite catalysts are used in the field of catalysis and meet the requirements of green chemistry, and its synthesis technology is gradually trending towards environmental protection with the development of green chemistry. Zeolite catalysts are widely used in chemical industry and other fields, and their green environmental protection performance promotes the development of chemical processes in the direction of green chemicals.

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Heydari, Somayyeh, Davood Habibi und Alireza Faraji. „A Green and Efficient Solvent- and Catalyst-Free Ultrasonic Dibenzylation Procedure“. Chemistry & Chemical Technology 16, Nr. 1 (20.02.2022): 126–32. http://dx.doi.org/10.23939/chcht16.01.126.

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A greener improvement was achieved for the synthesis of diverse N,N-dibenzylated compounds from the reaction of various aromatic amines with benzyl bromide using the ultrasound irradiation in solvent- and catalyst-free conditions. The dibenzylation reactions were carried out in different solvents and solvent-free conditions under ultrasound irradiation at various temperatures. The yields were very low in all applied solvents, while in the solvent-free condition and at room temperature, the yields were excellent. Due to obtaining the high reaction yields, the catalyst was not used.

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Dr. D. Valli Sowbhagyam. „Ionic Liquids as Green Solvents: A Comprehensive Review“. International Research Journal on Advanced Engineering Hub (IRJAEH) 2, Nr. 02 (29.02.2024): 220–24. http://dx.doi.org/10.47392/irjaeh.2024.0035.

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Common reaction media, volatile organic solvents (VOS), contribute significantly to air pollution and pose challenges in separation and recycling processes. As environmental awareness grows, researchers are focusing on developing alternative, eco-friendly solvent systems to replace these traditional VOS. Ionic liquids (ILs) have emerged as promising "green" solvents due to their extremely low vapor pressure and high thermal stability, providing advantages in containment, product recovery, and recyclability. ILs exhibit varying stability to moisture and miscibility with molecular liquids, and their properties like density, melting point, and viscosity can be tailored by selecting appropriate cation and/or anion components. Beyond their role in chemical reactions, ILs find applications in separations, extractions, electroanalytical processes, and chemical sensing. The high ionic character of ILs significantly enhances reaction rates in various chemical processes. These versatile features position ILs as potential alternatives to VOS in a wide range of industrial applications. Moreover, their use as industrial solvents can have economic, social, and ecological impacts by influencing human health and environmental factors. In summary, the exploration of ILs as green solvents represents a crucial step towards addressing environmental concerns associated with traditional volatile organic solvents in industrial chemical processes.

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Lapkin, Alexei A. „Editorial overview- Reaction engineering and Catalysis: Green chemical engineering“. Current Opinion in Chemical Engineering 26 (Dezember 2019): A3. http://dx.doi.org/10.1016/j.coche.2019.12.002.

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Devi, Barla Karuna, Swathi Naraparaju, Chaganti Soujanya und Sayan Dutta Gupta. „Green Chemistry and Green Solvents: An Overview“. Current Green Chemistry 7, Nr. 3 (02.12.2020): 314–25. http://dx.doi.org/10.2174/2213346107999200709132815.

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: Green chemistry emphasizes designing novel routes to overcome health and environmental problems that occur during a chemical reaction. Green solvents are used in place of conventional solvents that are hazardous to both human and the environment. Solvents like water, ionic liquids, supercritical CO2, biosolvents, organic carbonates, and deep eutectic mixtures can be used as green solvents. The review focuses on the properties, applications, and limitations of these solvents.

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Seyyedi, Behnam, Mohammad Edrisi, Maryam Seyyedi und Gholamreza Mahdavinia. „A new single step synthesis of copper phthalocyanine green using microwave irradiation effects in functionalisation of C−H bonds in aromatic rings“. Pigment & Resin Technology 43, Nr. 3 (29.04.2014): 113–17. http://dx.doi.org/10.1108/prt-04-2013-0029.

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Purpose – The paper introduces a new method for single step synthesis of copper phthalocyanine green pigment using microwave irradiation to activate C−H bonds on the aromatic rings that are possible by creation of chlorine radicals. The aims of this study are to investigate the possibility of high-efficiency product reaction, removing acidic wastewater, time optimization, and maximizing number of chlorine on aromatic rings. Design/methodology/approach – The paper presents a new synthesis technique, which does not have the problems of the conventional methods. Microwave irradiation is used as a chemical reaction initiator by creation of chlorine radicals in saturated aqueous solution of sodium chloride and C−H bond activation on aromatic rings. The approach yields to a high quality of product, uniform particle size distribution, high efficiency and an environmental friendly procedure. Findings – The paper introduces the use of suitable materials and water solvents in chemical reactions under microwave radiation at low temperatures. This shows that the microwave irradiation activates C−H bonds on aromatic rings and creates chlorine radicals at the same time, which results in relatively fast reaction of synthesis copper phthalocyanine green. Research limitations/implications – The ammonium molybdate catalyst, which is used in this method, should be weighed carefully. The effects of transition metals on chemical reactions in the presence of microwave irradiation can also be chlorinated other unsaturated bonds. Practical implications – The method develops a simple and practical solution to improve the synthesis of phthalocyanine green pigment. Originality/value – The synthesis method of copper phthalocyanine green pigment is novel. CuPhcCl16 has numerous applications in industrial.

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Firdaus, Maulidan, Nisrina Rahma Firdausi, Desy Nila Rahmana und Triana Kusumaningsih. „Green Metrics Evaluation on The Cannizzaro Reaction of p-Anisaldehyde and Benzaldehyde Under Solvent-Free Conditions“. Jurnal Kimia Valensi 9, Nr. 2 (28.12.2023): 288–99. http://dx.doi.org/10.15408/jkv.v9i2.35641.

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In the pursuit of environmentally responsible chemical processes, we conducted a thorough assessment of the green metrics associated with the Cannizzaro reaction using p-anisaldehyde and benzaldehyde under solvent-free conditions. This research elaborates the application of two different methods i.e., reflux and ultrasonication, applying potassium hydroxide (KOH) as the reagent. The progress of the Cannizzaro reaction was methodically followed via thin-layer chromatography (TLC), and the resulting products were characterized using various techniques, including melting point analysis, Fourier-transform infrared spectroscopy (FTIR), and gas chromatography-mass spectrometry (GC/MS). To measure the environmental impact and sustainability of these reactions, a multifaceted approach was used. Green metrics were evaluated by the state-of-the-art Environmental Assessment Tool for Organic Syntheses (EATOS) software, combined with the Andraos algorithm. Moreover, energy consumption calculations were evaluated. Reasonable analysis of the green metrics results was undertaken in the framework of prevailing literature, permitting to measure the level of eco-friendliness attained. Experimental findings revealed optimal conditions for the Cannizzaro reaction concerning p-anisaldehyde at a temperature of 50 °C for 90 minutes, resulting in remarkable of p-anisyl alcohol and p-anisic acid in 95.16% and 95.04% yields, respectively. Likewise, the reaction involving benzaldehyde reached its peak performance at 50 °C for 2 hours, giving benzyl alcohol and benzoic acid in 96.17% and 97.22% yields, respectively. Overall, the green metrics assessment and energy consumption calculations reliably confirmed that the solvent-free Cannizzaro reaction, when performed via ultrasonication, offers a reasonably greener and more energy-efficient method than the traditional ones. This research highlights the importance of sustainable chemical synthesis practices and their potential to reduce the environmental footprint of chemical processes.

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Tang, Christina, und Bridget T. McInnes. „Cascade Processes with Micellar Reaction Media: Recent Advances and Future Directions“. Molecules 27, Nr. 17 (31.08.2022): 5611. http://dx.doi.org/10.3390/molecules27175611.

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Reducing the use of solvents is an important aim of green chemistry. Using micelles self-assembled from amphiphilic molecules dispersed in water (considered a green solvent) has facilitated reactions of organic compounds. When performing reactions in micelles, the hydrophobic effect can considerably accelerate apparent reaction rates, as well as enhance selectivity. Here, we review micellar reaction media and their potential role in sustainable chemical production. The focus of this review is applications of engineered amphiphilic systems for reactions (surface-active ionic liquids, designer surfactants, and block copolymers) as reaction media. Micelles are a versatile platform for performing a large array of organic chemistries using water as the bulk solvent. Building on this foundation, synthetic sequences combining several reaction steps in one pot have been developed. Telescoping multiple reactions can reduce solvent waste by limiting the volume of solvents, as well as eliminating purification processes. Thus, in particular, we review recent advances in “one-pot” multistep reactions achieved using micellar reaction media with potential applications in medicinal chemistry and agrochemistry. Photocatalyzed reactions in micellar reaction media are also discussed. In addition to the use of micelles, we emphasize the process (steps to isolate the product and reuse the catalyst).

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Aranda, Carmen, und Gonzalo de Gonzalo. „Biocatalyzed Redox Processes Employing Green Reaction Media“. Molecules 25, Nr. 13 (01.07.2020): 3016. http://dx.doi.org/10.3390/molecules25133016.

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The application of biocatalysts to perform reductive/oxidative chemical processes has attracted great interest in recent years, due to their environmentally friendly conditions combined with high selectivities. In some circumstances, the aqueous buffer medium normally employed in biocatalytic procedures is not the best option to develop these processes, due to solubility and/or inhibition issues, requiring biocatalyzed redox procedures to circumvent these drawbacks, by developing novel green non-conventional media, including the use of biobased solvents, reactions conducted in neat conditions and the application of neoteric solvents such as deep eutectic solvents.

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Fabris, Fabrizio, Markus Illner, Jens-Uwe Repke, Alessandro Scarso und Michael Schwarze. „Is Micellar Catalysis Green Chemistry?“ Molecules 28, Nr. 12 (16.06.2023): 4809. http://dx.doi.org/10.3390/molecules28124809.

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Many years ago, twelve principles were defined for carrying out chemical reactions and processes from a green chemistry perspective. It is everyone’s endeavor to take these points into account as far as possible when developing new processes or improving existing ones. Especially in the field of organic synthesis, a new area of research has thus been established: micellar catalysis. This review article addresses the question of whether micellar catalysis is green chemistry by applying the twelve principles to micellar reaction media. The review shows that many reactions can be transferred from an organic solvent to a micellar medium, but that the surfactant also has a crucial role as a solubilizer. Thus, the reactions can be carried out in a much more environmentally friendly manner and with less risk. Moreover, surfactants are being reformulated in their design, synthesis, and degradation to add extra advantages to micellar catalysis to match all the twelve principles of green chemistry.

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Hamzavi, Seyedeh Fazileh Fazileh, Shahla Jamili, Morteza Yousefzadi, Ali Mashinchian Moradi und Narges Amrollahi Biuki. „Silver Nanoparticles Supported on Chitosan as a Green and Robust Heterogeneous Catalyst for Direct Synthesis of Nitrogen Heterocyclic Compounds under Green Conditions“. Bulletin of Chemical Reaction Engineering & Catalysis 14, Nr. 1 (15.04.2019): 51. http://dx.doi.org/10.9767/bcrec.14.1.2105.51-59.

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The catalytic efficiency of silver nanoparticles supported on chitosan as a green, robust, and efficient nanocatalyst for the direct synthesis of biologically active compounds, such as: imidazole derivatives as well as pyrazine scaffolds through multi-component reactions strategy, have been demonstrated. In this work, imidazole derivatives were achieved via pseudo four-component reactions by utilization of benzaldehydes, benzils, anilines, and ammonium acetate under solvent-free conditions. Moreover, pyrazine scaffolds were synthesized through a three-component reaction of phenylenediamine derivatives, isocyanides and various ketones in water. The main advantages of this protocol are the reusability of the catalyst, operational simplicity, mild reaction conditions, and high-yielding. Copyright © 2019 BCREC Group. All rights reservedReceived: 19th January 2018; Revised: 10th September 2018; Accepted: 18th September 2018; Available online: 25th January 2019; Published regularly: April 2019How to Cite: Hamzavi, S.F., Jamili, S., Yousefzadi, M., Moradi, A.M., Biuki, N.A. (2019). Silver Nanoparticles Supported on Chitosan as a Green and Robust Heterogeneous Catalyst for Direct Synthesis of Nitrogen Heterocyclic Compounds under Green Conditions. Bulletin of Chemical Reaction Engineering & Catalysis, 14 (1): 51-59 (doi:10.9767/bcrec.14.1.2105.51-59)Permalink/DOI: https://doi.org/10.9767/bcrec.14.1.2105.51-59

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Ilia, Gheorghe, Vasile Simulescu, Nicoleta Plesu, Vlad Chiriac und Petru Merghes. „Wittig and Wittig–Horner Reactions under Sonication Conditions“. Molecules 28, Nr. 4 (18.02.2023): 1958. http://dx.doi.org/10.3390/molecules28041958.

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Carbonyl olefinations are among the most important organic syntheses that form C=C bonds, as they usually have high yields and in addition offer excellent stereoselectivity. Due to these advantages, carbonyl olefinations have important pharmaceutical and industrial applications. These reactions contain an additional step of an α-functionalized carbanion to an aldehyde or ketone to produce alkenes, but syntheses performed using metal carbene complexes are also known. The Wittig reaction is an example of carbonyl olefination, one of the best ways to synthesize alkenes. This involves the chemical reaction between an aldehyde or ketone with a so-called Wittig reagent, for instance phosphonium ylide. Triphenylphosphine-derived ylides and trialkylphosphine-derived ylides are the most common phosphorous compounds used as Wittig reagents. The Wittig reaction is commonly involved in the synthesis of novel anti-cancer and anti-viral compounds. In recent decades, the use of ultrasound on the Wittig reaction (and on different modified Wittig syntheses, such as the Wittig–Horner reaction or the aza-Wittig method) has been studied as a green synthesis. In addition to the advantage of green synthesis, the use of ultrasounds in general also improved the yield and reduced the reaction time. All of these chemical syntheses conducted under ultrasound will be described further in the present review.

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Ābele, E., R. Ābele, Ļ. Golomba, K. Rubina, J. Višņevska und T. Beresņeva. „"Green Chemical" Methods for the Regioselective Synthesis of 1-Hetarylsulfanyl-ω-Cyanoalkanes“. Latvian Journal of Chemistry 49, Nr. 1-4 (01.01.2010): 278–82. http://dx.doi.org/10.2478/v10161-010-0006-8.

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"Green Chemical" Methods for the Regioselective Synthesis of 1-Hetarylsulfanyl-ω-Cyanoalkanes Novel "green chemical" methods for the synthesis of 1-hetarylthio-ω-cyanoalkanes were elaborated. Phase transfer catalyst ((CH3)4NBr) effect on yield of alkylation reaction was demonstrated. 1-Hetarylthio-ω-cyanoalkanes were isolated in 49-86% yields.

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Li, Huan, Feng Qin, Lijuan Huang, Wenjing Jia, Mingliang Zhang, Xin Li und Zhengyu Shu. „Enzymatic synthesis of 2-phenethyl acetate in water catalyzed by an immobilized acyltransferase from Mycobacterium smegmatis“. RSC Advances 12, Nr. 4 (2022): 2310–18. http://dx.doi.org/10.1039/d1ra07946h.

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Although water is an ideal green solvent for organic synthesis, it is difficult for most biocatalysts to carry out transesterification reactions in water because of the reversible hydrolysis reaction.

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Kidwai, M. „Dry media reactions“. Pure and Applied Chemistry 73, Nr. 1 (01.01.2001): 147–51. http://dx.doi.org/10.1351/pac200173010147.

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Dry media reaction under microwaves is an effort toward "green chemistry". Effects of microwaves in dry media organic reactions have shown synthetic utility for the preparation of biodynamic heterocycles.

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Hájek, Martin, Aleš Vávra, Héctor de Paz Carmona und Jaroslav Kocík. „The Catalysed Transformation of Vegetable Oils or Animal Fats to Biofuels and Bio-Lubricants: A Review“. Catalysts 11, Nr. 9 (17.09.2021): 1118. http://dx.doi.org/10.3390/catal11091118.

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This review paper summarizes the current state-of-the-art of the chemical transformation of oils/fats (i.e., triacylglycerols) to the use of biofuels or bio-lubricants in the means of transport, which is a novelty. The chemical transformation is necessary to obtain products that are more usable with properties corresponding to fuels synthesized from crude oil. Two types of fuels are described—biodiesel (the mixture of methyl esters produced by transesterification) and green diesel (paraffins produced by hydrogenation of oils). Moreover, three bio-lubricant synthesis methods are described. The transformation, which is usually catalysed, depends on: (i) the type and composition of the raw material, including alcohols for biodiesel production and hydrogen for green diesel; (ii) the type of the catalyst in the case of catalysed reactions; (iii) the reaction conditions; and (iv) types of final products. The most important catalysts, especially heterogeneous and including reaction conditions, for each product are described. The properties of biodiesel and green diesel and a comparison with diesel from crude oil are also discussed.

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Mohammed, Tasneem, Aayesha Nasreen, Yahya S. Alqahtani, Ibrahim Ahmed Shaikh, Shakeel Iqubal, Shaik Honey Fathima und Aejaz A. Khan. „Green Synthesis of Therapeutically Active Heterocyclic Scaffolds: A Review“. Science of Advanced Materials 15, Nr. 6 (01.06.2023): 725–47. http://dx.doi.org/10.1166/sam.2023.4477.

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Green chemistry lowers chemical hazards during chemical design, manufacture, and use. By using cleaner solvents, catalysts, and reaction conditions, this technique reduces environmental pollution and boosts atom economy and energy efficiency. Rapid industrialization and urbanization are causing significant harm to our environment by releasing a lot of dangerous and undesired chemicals, gases, or other pollutants. The secrets hidden in nature and its by-products must now be discovered by us in order to enhance the synthesis of physiologically significant moieties and foster its growth. Heterocyclic compounds and its derivatives exhibit various biological potential like anticancer, antimicrobial, anticonvulsant, analgesic, antitubercular, antiinflammatory and cardiovascular activities. This make them good candidates for future medication discovery and give them the potential to be an arsenal for treating diseases. This article provides an overview of the numerous environmentally friendly and green synthetic techniques used to create diverse physiologically significant heterocyclic scaffolds in the period 2002–2022. It is anticipated that this compilation of pertinent information will be of significance and practical value to chemists specializing in organic and pharmaceutical domains, potentially stimulating additional advancements in reaction development within this captivating area of study.

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Saha, Pritam, und Koushik Mukherjee. „Zinc catalyzed, microwave irradiated Sonogashira reaction by Sodium Aluminate (NaAlO₂) as a base in water: A Green entente“. E3S Web of Conferences 405 (2023): 01008. http://dx.doi.org/10.1051/e3sconf/202340501008.

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The Sonogashira reaction (SNR) is undeniably the most applicable and efficient scheme in chemical synthesis, which involves the formation of C-C bonds by cross-coupling reaction (CCR) with terminal alkyne and halides of aryl or vinyl system. Typically, Pd serves as a catalyst for this reaction, with Cu serving as a co-catalysts and bases can be phosphine or amine. The applicability of such reactions lies in synthesizing medicines, heterocycles, and imitators in products of nature, biologically active complex compounds, nanomaterials, and other organic compounds. In this research, we could implement the SNR effectively without the need for the chemicals mentioned above reagents by using sodium aluminate (NaAlO2) as a base and catalyst as zinc under microwave irradiation (MWR) in water. The approach bears the potential to be in coherence with the principles of green chemistry and make reactions more atom-friendly. In order to achieve inexpensive and eco-friendly energy conditions, we developed one of the straightforward, concise, convergent protocols for sequential coupling and cyclization from Acetylenic species of quinoline-8-ol synthesized in situ by the CCR under MWR. Furthermore, the reaction used zinc as a catalyst and NaAlO2 as a base in the aqueous phase.

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Ajvazi, Njomza, und Stojan Stavber. „Direct Cross-Coupling of Alcohols with O-Nucleophiles Mediated by N-Iodosuccinimide as a Precatalyst under Mild Reaction Conditions“. Catalysts 11, Nr. 7 (17.07.2021): 858. http://dx.doi.org/10.3390/catal11070858.

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We report N-iodosuccinimide as the most efficient and selective precatalyst among the N-halosuccinimides for dehydrative O-alkylation reactions between various alcohols under high-substrate concentration reaction conditions. The protocol is non-metal, one-pot, selective, and easily scalable, with excellent yields; enhancing the green chemical profiles of these transformations.

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Yadav, J. S., und H. M. Meshram. „Green twist to an old theme. An eco-friendly approach“. Pure and Applied Chemistry 73, Nr. 1 (01.01.2001): 199–203. http://dx.doi.org/10.1351/pac200173010199.

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Owing to present environmental awareness, attempts are being made toward the evolution of environmentally benign processes using solid-supported reagents and microwave-assisted reactions. A newly developed, nonmetallic oxidative reagent, "clayan", has been exploited for various reactions such as deprotection, oxidation, oxidative coupling, and nitration and bromination of activated and deactivated arenes. In another green chemistry endeavor, reactions such as reduction and cyclization have been successfully carried out in dry media under microwave irradiation. The nonsolvent reaction, experimental simplicity, and enhanced selectivity are the main attractive features of the approach.

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Zou, Ruonan, Jingbo Yu und Ping Ying. „Electrochemical Construction of C–S Bond: A Green Approach for Preparing Sulfur-Containing Scaffolds“. Pharmaceutical Fronts 06, Nr. 01 (März 2024): e9-e19. http://dx.doi.org/10.1055/s-0044-1780505.

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AbstractThe organosulfur frameworks containing C–S bonds are important structural motifs in various biologically active molecules and functional materials. In this regard, transition-metal catalysis using chemical oxidants to prime reactions has emerged as the most common method, however, is prone to several side reactions such as dimerization and overoxidation. In recent years, organic electrosynthesis has become a hot topic due to its eco-friendly and mild process in which costly catalysts and toxic oxidants could be replaced by electrons. This perspective summarized the recently developed C–S bond electrosynthesis protocols, discussing and highlighting reaction features, substrate scope, as well as its application in pharmaceuticals, and the underlying reaction mechanisms. The study helps the development of electrochemical process-enabled C–S bond construction reactions in the future.

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Keglevich, György, Nóra Zsuzsa Kiss, Zoltán Mucsi, Erzsébet Jablonkai und Erika Bálint. „The synthesis of phosphinates: traditional versus green chemical approaches“. Green Processing and Synthesis 3, Nr. 2 (01.04.2014): 103–10. http://dx.doi.org/10.1515/gps-2013-0106.

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Abstract Three alternatives are discussed in comparison with the classical esterification of phosphinic chlorides by reaction with alcohols. All novel methods, such as microwave (MW)-assisted direct esterification, MW-assisted phase transfer catalyzed alkylating esterification and the propylphosphonic anhydride-promoted esterification, start from phosphinic acids and offer different advantages and disadvantages. The methods are analyzed from green chemical point of view.

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Hou, Qian, Zhao Zhang, Ting Ting Yang und Yan Zhang. „Green Preparation of an Environment-Responsive Polymer“. Advanced Materials Research 750-752 (August 2013): 1235–38. http://dx.doi.org/10.4028/www.scientific.net/amr.750-752.1235.

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Smart polymers are very important in many fields, such as biochemistry, fine chemicals and functional materials, etc. In this paper, poly (N-isopropyl acrylamide) (PNIPAm) was prepared by ultrasonics sonochemistry. In the reaction system, the monomer is N-isopropyl acrylamide (NIPAm), the crosslinker is N,N'-methylenebisacrylamide (BIS) and the solvent is tetrahydrofuran (THF). FTIR and UV-Vis were used to investigate the chemical constitution and phase transformation property of PNIPAm. The results show that it is successful to obtain PNIPAm. It has thermosensitivity. And its lower critical solution temperature is found to be 34°C. Therefore, a green preparation method for environment-responsive polymer is presented.

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Dujjanutat, Praepilas, Arthit Neramittagapong und Pakawadee Kaewkannetra. „H₂-Assisted Chemical Reaction for Green-Kerosene Production“. Defect and Diffusion Forum 364 (Juni 2015): 104–11. http://dx.doi.org/10.4028/www.scientific.net/ddf.364.104.

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In this work, the effect of catalysts, temperatures and different types of vegetable oil on the production of synthetic bio-fuel via a hydro-processing process called as a hydro-cracking reaction by high pressure pack bed reactor is investigated. Firstly, H2gas (95% purity) was fed into the reactor together with palm oil under two different catalysts (Pd/Al2O3and Pt/Al2O3) separately packed in the reactor. The effect of different temperatures (500°C and 530°C) was investigated and the pressure was applied and maintained at 5 MPa for both temperatures. The results revealed that, when the Pd/Al2O3catalyst was used the highest bio-fuel (approximately 90% at 500°C) after distillation can be produced. Then, palm oil and soybean oil were used to compare in the efficiency of kerosene fuel production. The reaction was operated at 500°C, 5 MPa under H2pressure on the presence of 0.5% Pd/Al2O3. The bio-fuel achieved the highest yields at about 88% and 69% in cases of palm oil and soybean oil. It was also classified as kerosene yield approximately 70% when palm oil was used as a feed stock and at about 55% for soybean oil. Some properties of the kerosene product were characterised. The viscosities were obtained at 1.75 and 1.84 mm2/s and provided 43.06 and 45.85 MJ/kg of heating combustion values when palm oil and soybean oil were used. In addition, the carbon distribution of the synthetic kerosene produced from palm oil was clearly shown to be in the range of C11-C13which is similar to kerosene fuel obtained from petroleum.

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Pawełczyk, Anna, Katarzyna Sowa-Kasprzak, Dorota Olender und Lucjusz Zaprutko. „Microwave (MW), Ultrasound (US) and Combined Synergic MW-US Strategies for Rapid Functionalization of Pharmaceutical Use Phenols“. Molecules 23, Nr. 9 (15.09.2018): 2360. http://dx.doi.org/10.3390/molecules23092360.

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Increasingly stringent regulations aimed at protection of the natural environment have stimulated the search for new synthetic methodologies in organic and medicinal chemistry having no or minimum harmful effect. An interesting approach is the use of alternative activation factors, microwaves (MW) or ultrasounds (US) and also their cross-combination, which has been tested in the fast and efficient creation of new structures. At present, an easy and green hybrid strategy (“Lego” chemistry) is generally recommended for the design of new substances from different chemistry building blocks. Often, selected biologically active components with specific chemical reactivities are integrated by a suitably designed homo- or heterodifunctional linker that modifies the functionality of the starting structure, allowing easy covalent linkage to another molecule. In this study, a fast introduction of heterodifunctional halogenoacidic linker to selected mono-, di- and triphenolic active substances, allowing their functionalization, was investigated. Nucleophilic substitution reaction was chosen to produce final ethers with the reactive carboxylic group from phenols. The functionalization was performed using various green factors initiating and supporting the chemical reactions (MW, US, MW-US). The benefits of the three green supporting methods and different conditions of reactions were analyzed and compared with the results of the reaction performed by conventional methods.

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Rajendran, A. „Silica Sulphuric Acid Catalyzed Fischer Esterification Reaction under Solventless Condition: A Novel Green Chemical Reaction“. American Chemical Science Journal 1, Nr. 1 (10.01.2011): 28–36. http://dx.doi.org/10.9734/acsj/2011/264.

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Dugar, Arpita, Anil Kumar, Rameshwar Ameta und Suresh C. Ameta. „A green chemical approach for nitration of aromatic compounds“. Macedonian Journal of Chemistry and Chemical Engineering 28, Nr. 2 (15.12.2009): 163. http://dx.doi.org/10.20450/mjcce.2009.206.

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Photochemical aromatic nitration of phenol and salicylic acid has been carried out in the presence of UV radiations and formation of products has been observed spectrophotometrically. The effect of various operating variables like pH, concentration of nitrite ion, formate ion, phenol and salicylic acid, etc. on the rate of the reaction has also been observed. A tentative mechanism involving NO2· radicals has been proposed for photochemical nitration of phenol and salicylic acid.

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Mondal, Dipayan, Pankaj Lal Kalar, Shivam Kori, Shovanlal Gayen und Kalpataru Das. „Recent Developments on Synthesis of Indole Derivatives Through Green Approaches and Their Pharmaceutical Applications“. Current Organic Chemistry 24, Nr. 22 (18.12.2020): 2665–93. http://dx.doi.org/10.2174/1385272824999201111203812.

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Indole moiety is often found in different classes of pharmaceutically active molecules having various biological activities including anticancer, anti-viral, anti-psychotic, antihypertensive, anti-migraine, anti-arthritis and analgesic activities. Due to enormous applications of indole derivatives in pharmaceutical chemistry, a number of conventional synthetic methods as well as green methodology have been developed for their synthesis. Green methodology has many advantages including high yields, short reaction time, and inexpensive reagents, highly efficient and environmentally benign over conventional methods. Currently, the researchers in academia as well as in pharmaceutical industries have been developing various methods for the chemical synthesis of indole based compounds via green approaches to overcome the drawbacks of conventional methods. This review reflects the last ten years developments of the various greener methods for the synthesis of indole derivatives by using microwave, ionic liquids, water, ultrasound, nanocatalyst, green catalyst, multicomponent reaction and solvent-free reactions etc. (please see the scheme below). Furthermore, the applications of green chemistry towards developments of indole containing pharmaceuticals and their biological studies have been represented in this review.

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Lee, Seng Hua, Paridah Md Tahir, Wei Chen Lum, Li Peng Tan, Paiman Bawon, Byung-Dae Park, Syeed SaifulAzry Osman Al Edrus und Ummi Hani Abdullah. „A Review on Citric Acid as Green Modifying Agent and Binder for Wood“. Polymers 12, Nr. 8 (29.07.2020): 1692. http://dx.doi.org/10.3390/polym12081692.

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Citric acid (CA) can be found naturally in fruits and vegetables, particularly citrus fruit. CA is widely used in many fields but its usage as a green modifying agent and binder for wood is barely addressed. Esterification is one of the most common chemical reactions applied in wood modification. CA contains three carboxyl groups, making it possible to attain at least two esterification reactions that are required for crosslinking when reacting with the hydroxyl groups of the cell wall polymers. In addition, the reaction could form ester linkages to bring adhesivity and good bonding characteristics, and therefore CA could be used as wood binder too. This paper presents a review concerning the usage of CA as a wood modifying agent and binder. For wood modification, the reaction mechanism between wood and CA and the pros and cons of using CA are discussed. CA and its combination with various reactants and their respective optimum parameters are also compiled in this paper. As for the major wood bonding component, the bonding mechanism and types of wood composites bonded with CA are presented. The best working conditions for the CA in the fabrication of wood-based panels are discussed. In addition, the environmental impacts and future outlook of CA-treated wood and bonded composite are also considered.

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Fantucci, Hugo, Jaspreet S. Sidhu und Rafael M. Santos. „Mineral Carbonation as an Educational Investigation of Green Chemical Engineering Design“. Sustainability 11, Nr. 15 (01.08.2019): 4156. http://dx.doi.org/10.3390/su11154156.

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Engaging students in the experimental design of “green” technology is a challenge in Chemical Engineering undergraduate programs. This concept paper demonstrates an educational methodology to investigate accelerated mineral carbonation, which is a promising technology related to mitigation of climate change by sequestering carbon dioxide (CO2) from industrial sources as stable solid carbonates. An experimental investigation is conceived, whereby students test the effect of two process parameters (CO2 pressure and mixing rate) on the extent of carbonation reaction. The carbonation reaction has been performed using a mineral called wollastonite (CaSiO3). The experimental study and laboratory report cover principles of reaction kinetics and mass transfer, while illustrating the steps to develop and investigate a green process technology. The results from the experimental investigation, which is carried out by multiple teams of students, are then pooled and used to guide a subsequent design project. Students would conceive a flowsheet, size equipment, and estimate the energy demand and net CO2 sequestration efficiency of a full-scale implementation of the mineral carbonation technology. This educational investigation aims to help undergraduate students to acquire deeper experiential learning and greater awareness of future green technologies by applying fundamental engineering principles into an engaging experimental and design exercise.

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Earle, Martyn J., Natalia V. Plechkova und Kenneth R. Seddon. „Green synthesis of biodiesel using ionic liquids“. Pure and Applied Chemistry 81, Nr. 11 (31.10.2009): 2045–57. http://dx.doi.org/10.1351/pac-con-08-11-07.

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This paper is a hybrid starting with an overview and history of biodiesel synthesis and finishing with a description with some of our latest unpublished data. Initially, we examine "green" ways of obtaining biodiesel using ionic liquids, which can have an acidic or basic functionality, and can function both as a solvent and catalyst for the (trans)esterification reaction to obtain biodiesel. Both animal and vegetable resources can be utilized as a resource for (trans)esterification reactions depending on the geographical area. Biodiesel is of great interest because it enables motor vehicle transport using a renewable resource, while reducing the amount of carbon dioxide from fossil fuels being released into the environment.

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Sharma, Sachin, Gaurav Joshi, Sourav Kalra, Sandeep Singh und Raj Kumar. „Synthetic Versus Enzymatic Pictet-Spengler Reaction: An Overview“. Current Organic Synthesis 15, Nr. 7 (16.10.2018): 924–39. http://dx.doi.org/10.2174/1570179415666180613084014.

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Background: Pictet-Spengler reactions is an irreplaceable part of cyclization reaction leading to the formation of indispensable heterocyclic moieties including imidazole, benzoxazole, pyrrole, indole and others having immense biological and chemical significance. Researchers have explored this reaction using different types of catalysts and reactions conditions (including solvents, acids, etc.) to ensure the better selectivity, less reaction time and high product yields. A total of five Pictet-Spenglerases have been discovered from various sources including plants, animals, fungi, and microbes, and are responsible for the synthesis of various important alkaloids of biological medicinal importance. Objective: The present review is a strenuous effort to assemble information mainly focusing on synthetic as well as biological Pictet-Spengler reactions catalysed by enzymes called Pictet-Spenglerase. Conclusion: In the present review, the recent advances in the PS-mediated synthesis of diverse heterocycles such as tetrahydroisoquinoline, tetrahydro-β-carbolines, tetrahydroimidazopyridines and other fused heterocycles via chemical as well as enzymatic pathways have been covered. The compounds find their scope as medicinal agents for the treatment of cancer, tuberculosis, bacterial infection, leishmanial, etc. The compilation is expected to provide a mechanistic insight to chemists to enhance the reaction condition, yields and another parameter to ensure the safe and inexpensive reaction conditions considering the “Green-Concept” of chemistry.

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Chavan, Prashant, Suhas Pednekar, Ramesh Chaughule und Anushree Lokur. „Microwave-assisted Efficient One-pot Synthesis of Nitriles Using Recyclable Magnetite (Fe3O4) Nanoparticles as Catalyst and Water as Solvent: A Greener Approach“. Nanoscience & Nanotechnology-Asia 10, Nr. 4 (26.08.2020): 507–17. http://dx.doi.org/10.2174/2210681209666190218144322.

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Background: There has been an increasing curiosity over the past few years to carry out organic reactions over heterogeneous nanocatalysts. Microwave activation coupled with a nanocatalyst along with water as a reaction medium makes the process further green. Microwave activation as a green process reduces reaction times, enhances product purity and improves chemical yield. Methods: Nitrile group chemistry has been explored by many researchers across the globe owing to its interesting properties and its importance in synthetic chemistry. Despite several methods being available for the synthesis of nitriles, microwave assisted synthesis of nitriles using Fe3O4 nanoparticles appears more promising. The present study is intended at developing a recyclable magnetite (Fe3O4) nanoparticles catalyzed protocol towards the synthesis of organonitrile derivatives using one pot reaction. Results: The above protocol incorporates the use of microwave for heating and water as reaction medium. Several substituted nitriles could be synthesized for excellent yields. The magnetite nanoparticles can be reused for new reaction without significant loss in activity. Conclusion: The experiment makes the protocol simple, environment friendly and economically feasible.

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Jameel, Mahmood S., Azlan Abdul Aziz und Mohammed Ali Dheyab. „Green synthesis: Proposed mechanism and factors influencing the synthesis of platinum nanoparticles“. Green Processing and Synthesis 9, Nr. 1 (28.07.2020): 386–98. http://dx.doi.org/10.1515/gps-2020-0041.

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AbstractPlatinum nanoparticles (Pt NPs) have attracted interest in catalysis and biomedical applications due to their unique structural, optical, and catalytic properties. However, the conventional synthesis of Pt NPs using the chemical and physical methods is constrained by the use of harmful and costly chemicals, intricate preparation requirement, and high energy utilization. Hence, this review emphasizes on the green synthesis of Pt NPs using plant extracts as an alternative approach due to its simplicity, convenience, inexpensiveness, easy scalability, low energy requirement, environmental friendliness, and minimum usage of hazardous materials and maximized efficiency of the synthesis process. The underlying complex processes that cover the green synthesis (biosynthesis) of Pt NPs were reviewed. This review affirms the effects of different critical parameters (pH, reaction temperature, reaction time, and biomass dosage) on the size and shape of the synthesized Pt NPs. For instance, the average particle size of Pt NPs was reported to decrease with increasing pH, reaction temperature, and concentration of plant extract.

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Saha, Moumita, und Asish R. Das. „Nanocrystalline ZnO: A Competent and Reusable Catalyst for the Preparation of Pharmacology Relevant Heterocycles in the Aqueous Medium“. Current Green Chemistry 7, Nr. 1 (15.05.2020): 53–104. http://dx.doi.org/10.2174/2213346107666200218122718.

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: Nanoparticle catalyzed synthesis is a green and convenient method to achieve most of the chemical transformations in water or other green solvents. Nanoparticle ensures an easy isolation process of catalyst as well as products from the reaction mixture avoiding the hectic work up procedure. Zinc oxide is a biocompatible, environmentally benign and economically viable nanocatalyst with effectivity comparable to the other metal nanocatalyst employed in several reaction strategies. This review mainly focuses on the recent applications of zinc oxide in the synthesis of biologically important heterocyclic molecules under sustainable reaction conditions. : Application of zinc oxide in organic synthesis: Considering the achievable advantages of this nanocatalyst, presently several research groups are paying attention in anchoring zincoxide or its modified structure in several types of organic conversions e.g. multicomponent reactions, ligand-free coupling reactions, cycloaddition reaction, etc. The advantages and limitations of this nanocatalyst are also demonstrated. The present study aims to highlight the recent multifaceted applications of ZnO towards the synthesis of diverse heterocyclic motifs. Being a promising biocompatible nanoparticle, this catalyst has an important contribution in the fields of synthetic chemistry and medicinal chemistry.

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Tagawa, Tomohiko. „Reaction Engineering of Microchannel Catalytic Reactors for Green Process“. Applied Mechanics and Materials 625 (September 2014): 285–88. http://dx.doi.org/10.4028/www.scientific.net/amm.625.285.

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It is essential to introduce green sustainable chemical process into developing countries. Use of microchannel reactors is one of the future solutions. Especially, application of multiphase catalytic system should be studied in the reaction engineering view point. Examples of application of catalysts to microchannel reactors were introduced such as: Use of phase transfer catalysts in multi phase parallel flow reactors, Use of phase transfer catalysts with the aid of ultrasonic irradiation in multiphase slug flow capillary reactors and Preparation of gas phase tube wall type catalytic reactors which were evaluated with microscopic FT-IR and UV spectrometer.

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Nagieva, I. T., N. I. Ali-zadeh und T. М. Nagiev. „COHERENT SYNCHRONIZATION OF PYRIDINE DIMERIZATION REACTIONS AND DECOMPOSITION OF “GREEN OXIDANTS” – H2O2 AND N2O“. Azerbaijan Chemical Journal, Nr. 4 (08.12.2021): 6–11. http://dx.doi.org/10.32737/0005-2531-2021-4-6-11.

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In recent years, hydrogen peroxide and nitrous oxide (1) "green oxidants" – have attracted much attention of researchers as a selective oxidizing agent for the catalytic oxidation of pyridine bases. In this regard, the reaction of pyridine oxidation by hydrogen peroxide and nitrous oxide under homogeneous conditions, in the gas phase, without the use of catalysts, at atmospheric pressure, has been experimentally investigated. Areas of selective oxidation of pyridine with hydrogen peroxide and nitrous oxide have been established, and optimal conditions have been found for obtaining valuable raw materials required in the petrochemical, chemical, and pharmaceutical industries

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XIA, XINXING, MINGZHU DU und XIUJUAN GENG. „Removal of silicon from green liquor with carbon dioxide in the chemical recovery process of wheat straw soda pulping“. March 2013 12, Nr. 3 (01.04.2013): 35–40. http://dx.doi.org/10.32964/tj12.3.35.

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Green liquor in the chemical recovery process of wheat straw pulping was treated with carbon dioxide to precipitate silicon by a one-step process and a seeding process to address problems caused by high silicon content. The total silicon removal, the particle size, and the sedimentation performance of silica were investigated. The results showed that the pH of green liquor decreased with increasing amounts of carbon dioxide, becoming stable after the pH decreased to 8.2. Reaction temperature had no significant effect on the removal of silicon. About 99% of silicon removal was achieved at a pH of 9.2 at room temperature. In the one-step process, the particle size increased and the silica sedimentation performance improved with decreasing pH. The particle size decreased and the sedimentation performance improved with increasing reaction temperature. At a pH of 9.5 and reaction temperature of 80°C, the particle size was 10.43 μm. In the seeding process, 40% green liquor was treated with carbon dioxide at 80°C until the pH was about 10.5, then the 40% treated green liquor was mixed with the remaining 60% of green liquor. The mixture was then treated with carbon dioxide at a reaction temperature of 80°C until the pH reached 9.5. In that situation, the particle size reached 14.11 μm. Compared with the one-step process, the particle size of silica generated by the seeding process was bigger and the sedimentation performance was improved.

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