@article { ISI:000226532000006, title = {Selective synthesis of N,N-dimethyl aniline derivatives using dimethyl carbonate as a methylating agent and onium salt as a catalyst}, journal = {Journal of Molecular Catalysis A - Chemical}, volume = {226}, number = {1}, year = {2005}, month = {FEB}, pages = {49-56}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

N-Alkylation of anilines by dimethyl carbonate (DMC) catalyzed by onium salts has been demonstrated. The work presented here shows that a simple catalytic system consisting of onium salts in the presence of a small amount of water is extremely effective in enhancing the DMC mediated N-alkylation of anilines to dialkylated products. The effect of reaction conditions on the synthesis of N,N-dimethyl aniline (NNDMA) from aniline and DMC has been investigated. Under the optimized conditions highest yield of NNDMA obtained was 99.8\%, which is the best reported for liquid phase N-alkylation of aniline using DMC. The role of water in enhancing the yield of NNDMA is explained and a reaction-networking scheme is constructed, which summarizes the chemistry behind liquid phase N-alkylation of anilines by DMC. The catalyst has been shown to recycle up to five times and at the end of fifth recycle almost 98\% of NNDMA yields were obtained. (C) 2004 Elsevier B.V. All rights reserved.

}, keywords = {Aniline, Dimethyl carbonate, methylation, N, N-alkylation, N-dimethyl aniline, onium salts}, issn = {1381-1169}, doi = {10.1016/j.molcata.2004.09.025}, author = {Shivarkar, A. B. and Gupte, S. P. and Chaudhari, Raghunath V.} } @article { ISI:000239326400005, title = {Fe-Zn double-metal cyanide complexes as novel, solid transesteritication catalysts}, journal = {Journal of Catalysis}, volume = {241}, number = {1}, year = {2006}, month = {JUL}, pages = {34-44}, publisher = {ACADEMIC PRESS INC ELSEVIER SCIENCE}, type = {Article}, address = {525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA}, abstract = {

Fe-Zn double-metal cyanide complexes are currently used as catalysts for the ring-opening polymerization of epoxides, as well as the coupling of epoxides and CO2 for the production of polycarbonates. We report their novel application as highly efficient solid catalysts for the transesterification reactions of carbonates. The catalysts were prepared from aqueous solutions of ZnCl2 and K4Fe(CN)(6) in the presence of tert-butanol (complexing agent) and tri-block copolymer EO20PO70EO20 (average molecular weight, 5800; co-complexing agent). They were characterized by chemical analysis, XRD, thermal analysis, N-2 adsorption, magnetic susceptibility, SEM, and FTIR, diffuse reflectance UV-visible, EPR, and X-ray photoelectron spectroscopies. Their acidity was determined from the IR spectra of adsorbed pyridine and the temperature-programmed desorption of NH3. Catalyst samples prepared with both complexing and co-complexing agents were found to be more acidic and catalytically active than those prepared without these agents. These catalysts are more active/selective than other solid catalysts hitherto reported. Dimethyl carbonate, for example, could be synthesized with 100\% selectivity and an isolated yield of \>86\% by the reaction of propene carbonate with methanol. The catalysts can be recycled without significant loss in activity. Lewis acidic Zn ions are the possible active sites for the transesterification reaction. (c) 2006 Published by Elsevier Inc.

}, keywords = {cyclic carbonate, Dimethyl carbonate, double metal cyanide Fe-Zn complexes, organic carbonate, transesterification catalyst}, issn = {0021-9517}, doi = {10.1016/j.jcat.2006.04.002}, author = {Srivastava, R. and Srinivas, D. and Ratnasamy, P.} } @article { ISI:000240639000014, title = {Transesterification of cyclic carbonates with methanol at ambient conditions over tungstate-based solid catalysts}, journal = {Applied Catalysis A-General}, volume = {312}, year = {2006}, month = {SEP}, pages = {108-114}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Dimethyl carbonate synthesis with 80 mol\% yield is achieved through transesterification of ethylene carbonate with methanol at ambient conditions (RT and atmospheric pressure) using alkali and alkaline-earth tungstates as solid catalysts. The catalysts are efficient even at the sub-ambient temperatures. Reactions under CO2 pressure indicate that CO2 atmosphere retards the transesterification reaction completely below 100 degrees C. Experimental conditions of 150 degrees C and 3.4 MPa CO2 pressure are required to obtain maximum DMC yield of 71 mol\%. Synthesis of DMC by one-pot synthesis using epoxide, CO2 and methanol is not as effective as that by two-step method with the present catalyst system. Raman and IR spectra of methanol-interacting tungstates indicate the formation of a methoxide ion species adsorbed at the catalyst surface as one possible reaction intermediates. (C) 2006 Elsevier B.V. All rights reserved.

}, keywords = {Dimethyl carbonate, ethylene carbonate, heterogeneous catalyst, Raman spectroscopy, sodium tungstate, transesterification}, issn = {0926-860X}, doi = {10.1016/j.apcata.2006.06.034}, author = {Sankar, M. and Nair, C. Madhavan and Murty, K. V. G. K. and Manikandan, Palanichamy} } @article { ISI:000261275000005, title = {Non-phosgene route for the synthesis of methyl phenyl carbamate using ordered AISBA-15 catalyst}, journal = {Journal of Molecular Catalysis A-Chemical}, volume = {295}, number = {1-2}, year = {2008}, month = {NOV}, pages = {29-33}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Methyl phenyl carbamate (MPC) has been synthesized Under liquid phase conditions from dimethyl carbonate and aniline by using mesoporous AISBA-15 catalyst. The catalyst with different Si/Al ratio was synthesized by isomorphous Substitution of aluminium into the framework of siliceous SBA-15. The structural integrity of the catalyst system was diagnosed with the help of various characterization techniques Such as X-ray diffraction, Surface analysis, and the acidity measurement has been done by TPD using ammonia as probe molecule. AISBA-15 (Si/Al = 10) exhibited highest catalytic activity in the synthesis of MPC under the reaction Conditions Studied. The effect of parameters Such as molar ratio of reactants, catalyst concentration. reaction temperature and time on the conversion of aniline was investigated. The results demonstrated that an aniline conversion of 99\% and MPC selectivity of 71\% were achieved when the reaction was carried out at 100 C, DMC to aniline mole ratio of 10 with 5\% of catalyst (wt\% of total reaction mixture) for 3 h. (c) 2008 Elsevier B.V. All rights reserved.

}, keywords = {amines, Dimethyl carbonate, Mesoporous AISBA-15, Methoxycarbonylation, Methyl phenyl carbamate}, issn = {1381-1169}, doi = {10.1016/j.molcata.2008.08.009}, author = {Lucas, Nishita and Amrute, Amol P. and Palraj, K. and Shanbhag, G. V. and Vinu, Ajayan and Halligudi, Shivaraj B.} } @article { ISI:000377891600014, title = {Direct synthesis of dimethyl carbonate from CO2 and methanol over CeO2 catalysts of different morphologies}, journal = {Journal of Chemical Sciences}, volume = {128}, number = {6}, year = {2016}, month = {JUN}, pages = {957-965}, publisher = {INDIAN ACAD SCIENCES}, address = {C V RAMAN AVENUE, SADASHIVANAGAR, P B \#8005, BANGALORE 560 080, INDIA}, abstract = {

The direct synthesis of dimethyl carbonate (DMC) from carbon dioxide (CO2) and methanol is an attractive approach towards conversion of the greenhouse gas - CO2 into value-added chemicals and fuels. Ceria (CeO2) catalyzes this reaction. But the conversion efficiency of CeO2 is enhanced when the byproduct water in the reaction medium is separated by employing trapping agents like 2-cyanopyridine (2-CP). In this work, the influence of morphology of CeO2 on the direct synthesis of DMC in presence of 2-CP is reported. CeO2 catalysts of cube, rod, spindle and irregular morphology (Ce - C, Ce - R, Ce - S and Ce - N, respectively) were prepared, characterized and studied as catalysts in the said reaction conducted in a batch mode. Among all, Ce - S shows superior catalytic performance with nearly 100 mol\% of DMC selectivity. Catalytic activity correlates with the concentration of acid and base sites of medium strength as well as defect sites. Ce - S has an optimum number of these active sites and thereby shows superior catalytic performance.

}, keywords = {acid-base catalysis, ceria, CO2 utilization, Dimethyl carbonate, influence of morphology}, issn = {0974-3626}, doi = {10.1007/s12039-016-1094-0}, author = {Unnikrishnan, P. and Darbha, Srinivas} } @article {43977, title = {MgFeCe ternary layered double hydroxide as highly efficient and recyclable heterogeneous base catalyst for synthesis of dimethyl carbonate by transesterification}, journal = {Catalysis Letters}, volume = {147}, year = {2017}, month = {OCT}, pages = { 2558-2569}, type = {Journal Article}, abstract = {A series of Mg3:Fex + Ce1-x LDHs (3:1) were synthesized by co-precipitation method by varying molar ratio of Fe:Ce between 1:0 to 0:1 (LDH-1 to LDH-6). All synthesized LDHs were characterized by XRD, FT-IR, TEM, N2 sorption, benzoic acid titration and XPS in detail and evaluated for selective synthesis of dimethyl carbonate by transesterification of ethylene carbonate with methanol. It was demonstrated that the structural and basic properties of synthesized LDHs were strongly dependent on the Fe:Ce molar ratio (Ce concentration). The correlation between their physicochemical properties and catalytic performance was studied in detail. Among all synthesized LDHs the best result was obtained with LDH-3 (Fe:Ce = 0.85:0.15) where LDH structure remained intact, and showed high number of strong basic sites on LDH surface. LDH-3 was recycled 7 times while maintaining high catalyst activity and selectivity towards DMC. The obtained results elucidate the important role of Ce in modifying the basic properties of LDH in enhancing the catalytic activity for DMC synthesis. Graphical Abstract: [Figure not available: see fulltext.]. {\textcopyright} 2017, Springer Science+Business Media, LLC.}, keywords = {Dimethyl carbonate, ethylene carbonate, Mg{\textendash}Fe{\textendash}Ce Ternary Hydrotalcite, transesterification}, doi = {10.1007/s10562-017-2146-x}, author = {Nivangune, N. T.}, editor = {Ranade, V. V.} } @article {47596, title = {Comprehensive review on catalytic O-alkylation of phenol and hydroquinone}, journal = {Catalysis Reviews-Science and Engineering}, volume = {65}, year = {2023}, month = {APR}, pages = {455-500}, type = {Review}, abstract = {

The alkylation process involves two competitive paths of O- and C-alkylation and achieving better selectivity for desired products is a very challenging problem. The development of new process for synthesis of O-methylated products of phenol and dihydric phenols is a subject of high industrial and academic interest. Alkyl phenyl ethers, especially anisole and 4-methoxyphenol, have captivated significant interest due to their increasing applications in pharmaceutical industries. The main emphasis of the present review is to explore the recent development in two catalytic O-alkylation processes. The first process is O-methylation of phenol into anisole and another is selective mono O-methylation of hydroquinone into 4-methoxyphenol. The present article covers O-alkylation methods with methanol and dimethyl carbonate as alkylating agent over various acidic and basic catalytic systems. The catalyst systems analyzed involves Bronsted and Lewis acidic and basic ionic liquids, conventional acids, metal oxides, solid acid and basic catalysts, hydrotalcites, various zeolites and heteropolyacids. The mechanistic behavior of alkylation reactions in presence of different catalytic system is reviewed critically which is important to design new and/or modified catalyst in order to maximize the yield of desired product. Additionally, an influence of reaction parameters, role of catalyst and their active sites on product distribution is described. The review paper gives useful insight for researchers in the field of catalysis and reaction engineering of alkylation reactions. Understandings of the reaction pathways will help in developing reliable kinetic models necessary for process scale-up to industrial scale reactor system.

}, keywords = {Dimethyl carbonate, Hydroquinone, Methanol, O-alkylation, phenol}, issn = {0161-4940}, doi = {10.1080/01614940.2021.1930490}, author = {Bhongale, Priyanka and Joshi, Sunil and Mali, Nilesh} } @article {49346, title = {Reactive distillation configuration for the production of ethyl acrylate}, journal = {CHEMICAL ENGINEERING AND PROCESSING-PROCESS INTENSIFICATION}, volume = {203}, year = {2024}, month = {SEP}, type = {Journal Article}, keywords = {ACETIC-ACID, CYCLOHEXYL ACETATE, Design, Dimethyl carbonate}, issn = {0255-2701}, doi = {10.1016/j.cep.2024.109864}, author = {Gore, Jayram I. and Mahajani, Sanjay M. and Mali, Nilesh A.} }