@article { ISI:000226532100006, title = {Factors affecting activation and utilization of carbon dioxide in cyclic carbonates synthesis over Cu and Mn peraza macrocyclic complexes}, journal = {Journal of Molecular Catalysis A - Chemical}, volume = {226}, number = {2}, year = {2005}, month = {FEB}, pages = {199-205}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

The catalytic activities of several Cu and Mn aza complexes for cyclic carbonate synthesis from CO2 and epoxides are reported. The various factors affecting activation of CO2 by metal complexes and its utilization in cyclic carbonate synthesis have been investigated. Fr-IR, UV-vis and EPR spectroscopic investigations reveal that CO2 coordinates to Cu in eta(1)-C mode of coordination. Nature of the ligand and substitution influence the lability of metal-CO2 bonding. The differences in the catalytic activities are correlated with the mode and strength of CO2 binding. (C) 2004 Elsevier B.V. All rights reserved.

}, keywords = {benign synthesis, Carbon dioxide, catalysis by Cu and Mn complexes, CO2 activation, CO2 fixation, CO2 utilization, cyclic carbonates, polycarbonates, spectroscopy}, issn = {1381-1169}, doi = {10.1016/j.molcata.2004.10.034}, author = {Srivastava, R. and Bennur, T. H. and Srinivas, D.} } @article { ISI:000238111400026, title = {Syntheses of polycarbonate and polyurethane precursors utilizing CO2 over highly efficient, solid as-synthesized MCM-41 catalyst}, journal = {Tetrahedron Letters}, volume = {47}, number = {25}, year = {2006}, month = {JUN}, pages = {4213-4217}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

As-synthesized MCM-41 was used as a reusable, heterogeneous catalyst for the eco-friendly synthesis of cyclic carbonate precursors of polycarbonates via a cycloaddition reaction of CO2 with epoxides. This catalyst is also efficient for the synthesis of alkyl and aryl carbamate precursors of polyurethanes via the reaction of amines, CO2 and alkyl halides. Both these reactions were carried out under mild conditions and without using any solvent or co-catalyst. CO2 is utilized as a raw material replacement for toxic phosgene in the conventional synthesis of these chemicals. (c) 2006 Elsevier Ltd. All rights reserved.

}, keywords = {carbamates, carbon dioxide utilization, CO2 fixation, cyclic carbonates, eco-friendly processes, MCM-41, polycarbonates, polyurethanes}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2006.04.057}, author = {Srivastava, R. and Srinivas, D. and Ratnasamy, P.} } @article { ISI:000315069400009, title = {Catalytic activity of ZIF-8 in the synthesis of styrene carbonate from CO2 and styrene oxide}, journal = {Catalysis Communications}, volume = {32}, year = {2013}, month = {FEB}, pages = {36-40}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

The catalytic activity of ZIF-8 in the synthesis of styrene carbonate from carbon dioxide and styrene oxide is presented. ZIF-8 crystals displayed catalytic activity even at temperatures as low as 50 degrees C, with styrene carbonate yields as high as similar to 54\% at 100 degrees C. In contrast to many prior-art catalysts, solvents or co-catalysts were not required. Pyridine and ammonia were used as probe molecules to estimate the type and density of acid sites in fresh and reused ZIF-8 catalysts. DRIFT spectroscopy of adsorbed pyridine revealed the presence of both Bronsted (B) and Lewis (L) acid sites. The B-sites have nearly vanished in the case of recycled ZIF-8 catalysts. The simultaneous presence of both the acid sites and the nitrogen basic moieties from the imidazole linker in ZIF-8 promoted the adsorption of the CO2 on the solid surface and its further conversion to the cyclic carbonate. The ZIF-8 catalysts could be recycled and reused without significant loss in catalytic activity. Published by Elsevier B.V.

}, keywords = {CO2 conversion, cyclic carbonates, Styrene carbonate, Zeolitic imidazolate frameworks, ZIF-8}, issn = {1566-7367}, doi = {10.1016/j.catcom.2012.12.003}, author = {Zhu, Minqi and Srinivas, Darbha and Bhogeswararao, Seemala and Ratnasamy, Paul and Carreon, Moises A.} } @article { ISI:000328606500014, title = {One-pot synthesis of cyclic carbonates from aldehydes, sulfur ylide, and CO2}, journal = {Synlett}, volume = {25}, number = {1}, year = {2014}, month = {JAN}, pages = {97-101}, publisher = {GEORG THIEME VERLAG KG}, address = {RUDIGERSTR 14, D-70469 STUTTGART, GERMANY}, abstract = {

Treatment of aldehydes with sulfur ylide (CH2=SOMe2 or CH2=SMe2), in the presence of CO2 (1 atm) bubbled sequentially under mild conditions, produces cyclic carbonates in preparative yields. Sodium iodide formed in situ promotes the reaction between epoxide as intermediate and CO2 at ambient conditions, thus constituting a powerful metal-free synthesis of organic cyclic carbonates directly from aldehydes.

}, keywords = {Carbon dioxide, cyclic carbonates, cyclization, epoxides, Insertion}, issn = {0936-5214}, doi = {10.1055/s-0033-1340072}, author = {Aher, Ravindra D. and Kumar, B. Senthil and Sudalai, Arumugam} } @article {45886, title = {Supported imidazole as heterogeneous catalyst for the synthesis of cyclic carbonates from epoxides and CO2}, journal = {Catalysis Communications}, volume = {59}, year = {2015}, month = {JAN }, pages = {201-205}, type = {Article}, abstract = {

Imidazole anchored onto a silica matrix, by means of a propyl linkage, is found to be an effective heterogeneous catalyst for the synthesis of cyclic carbonates from epoxides and CO2 in near quantitative yield. The versatility of this catalyst is demonstrated by using different substrates (epichlorohydrin, propylene oxide, butylene oxide and styrene oxide) for this cycloaddition reaction. These CO2 insertion reactions were typically carried out in the temperature range of 343 to 403 K at 0.6 MPa CO2 pressure under solvent-free conditions. Several spectroscopic methods were used to characterize the catalyst and study the integrity of the fresh and spent catalysts. (C) 2014 Elsevier B.V. All rights reserved.

}, keywords = {Anchored imidazole, CO2 utilization, cyclic carbonates, epoxides}, issn = {1566-7367}, doi = {10.1016/j.catcom.2014.10.026}, author = {Sankar, Meenakshisundaram and Ajithkumar, Thalasseril G. and Sankar, Gopinathan and Manikandan, Palanichamy} } @article {46326, title = {Ag nanoparticles supported on a resorcinol-phenylenediamine-based covalent organic framework for chemical fixation of CO2}, journal = {Chemistry-An Asian Journal }, year = {2019}, month = {OCT}, type = {Article; Early Access}, abstract = {

Covalent organic frameworks are a new class of crystalline organic polymers possessing a high surface area and ordered pores. Judicious selection of building blocks leads to strategic heteroatom inclusion into the COF structure. Owing to their high surface area, exceptional stability and molecular tunability, COFs are adopted for various potential applications. The heteroatoms lining in the pores of COF favor synergistic host-guest interaction to enhance a targeted property. In this report, we have synthesized a resorcinol-phenylenediamine-based COF which selectively adsorbs CO2 into its micropores (12 angstrom). The heat of adsorption value (32 kJ mol(-1)) obtained from the virial model at zero-loading of CO2 indicates its favorable interaction with the framework. Furthermore, we have anchored small-sized Ag nanoparticles (approximate to 4-5 nm) on the COF and used the composite for chemical fixation of CO2 to alkylidene cyclic carbonates by reacting with propargyl alcohols under ambient conditions. Ag@COF catalyzes the reaction selectively with an excellent yield of 90 \%. Recyclability of the catalyst has been demonstrated up to five consecutive cycles. The post-catalysis characterizations reveal the integrity of the catalyst even after five reaction cycles. This study emphasizes the ability of COF for simultaneous adsorption and chemical fixation of CO2 into corresponding cyclic carbonates.

}, keywords = {CO2 capture, covalent organic frameworks, cyclic carbonates, Propargyl alcohols, silver nanoparticles}, issn = {1861-4728}, doi = {10.1002/asia.201901157}, author = {Chakraborty, Debanjan and Shekhar, Pragalbh and Singh, Himan Dev and Kushwaha, Rinku and Vinod, C. P. and Vaidhyanathan, Ramanathan} } @article {46886, title = {Triazine-based organic polymer-catalysed conversion of epoxide to cyclic carbonate under ambient CO2 pressure}, journal = {Chemistry-An Asian Journal}, volume = {15}, year = {2020}, month = {JUN }, pages = {1683-1687}, type = {Article}, abstract = {

In this work we have achieved epoxide to cyclic carbonate conversion using a metal-free polymeric catalyst under ambient CO2 pressure (1.02 atm) using a balloon setup. The triazine containing polymer (CYA-ANIS) was prepared from cyanuric chloride (CYA-Cl) and o-dianisidine (ANIS) in anhydrous DMF as solvent by refluxing under the N-2 gas environment. The presence of triazine and amine functional groups in the polymer results in the adsorption of CO2 up to 7 cc/g at 273 K. This inspired us to utilize the polymer for the conversion of a series of functionalised epoxides into their corresponding cyclic carbonates in the presence of tetrabutyl ammonium iodide (TBAI) as co-catalyst. The product has wide range of applications like solvent in lithium ion battery, precursor for polycarbonate, etc. The catalyst was efficient for the conversion of different mono and di-epoxides into their corresponding cyclic carbonates under atmospheric pressure in the presence of TBAI as co-catalyst. The study indicates that epoxide attached with electron withdrawing groups (like, CH2Cl, glycidyl ether, etc.) displayed better conversion compared to simple alkane chain attached epoxides. This is mainly due to the stabilization of electron rich intermediates produced during the reaction (e. g. epoxide ring opening or CO2 incorporation into the halo-alkoxide anion). This catalyst mixture was capable to maintain its reactivity up to five cycles without losing its activity. Post catalytic characterization clearly supports the heterogeneous and recyclable nature of the catalyst.

}, keywords = {CO2 fixation, cyclic carbonates, epoxides, Heterogeneouscatalyst, metal free catalyst, Triazinepolymer}, issn = {1861-4728}, doi = {10.1002/asia.201901277, Early Access Date = APR 2020}, author = {Biswas, Tanmoy and Halder, Arjun and Paliwal, Khusboo S. and Mitra, Antarip and Tudu, Gouri and Banerjee, Rahul and Mahalingam, Venkataramanan} } @article {49293, title = {Biobased reusable nonisocyanate polyurethane hot-melt adhesives with potential chemical degradability}, journal = {ACS Applied Polymer Materials}, volume = {6}, year = {2024}, month = {SEP}, pages = {11180-11192}, type = {Article}, abstract = {

Hot-melt adhesives (HMAs) derived from renewable resources are always attractive, as they promote less dependence on fossil resources and aid in developing environmentally friendly materials. However, developing sustainable HMAs exhibiting good adhesive performance and biodegradability remains challenging. Herein, reusable biobased HMAs with a high bio content of 88-90\%, biodegradability, and tunable adhesive nature were developed as a possible alternative to conventional petroleum-based hot-melt adhesives. Moreover, the structure-property relationship of the product was investigated in detail. By tailoring the monomer composition, NIPU-40 HMA exhibited a good bonding ability with a superior adhesion strength of 6.39 MPa. To the best of our knowledge, this is the highest adhesion strength observed when bonding with an Al substrate among the biobased thermoplastic NIPU-HMAs. Impressively, NIPU-HMAs could display excellent reusability even after three bonding and debonding cycles without a significant drop in the adhesive strength and were found to exhibit good adhesion performance under wet conditions. More importantly, the NIPU-HMAs are prone to degradation under acid-catalyzed conditions. Considering their features, these biobased NIPU thermoplastic hot-melt adhesives offer an opportunity to create environmentally friendly, degradable adhesives that possess excellent adhesive strength and can be reused multiple times.

}, keywords = {acid degradability, biobased NIPUs, cyclic carbonates, hot meltadhesives, lap shearstrength, spiro-aromatic}, issn = {2637-6105}, doi = {10.1021/acsapm.4c01526}, author = {Ghuge, Gorakh Hiraman and Torris, Arun and Nair, Kiran Sukumaran} }