@article { ISI:000231058000003,
	title = {Zeolite-based organic-inorganic hybrid catalysts for phosgene-free and solvent-free synthesis of cyclic carbonates and carbamates at mild conditions utilizing CO2},
	journal = {Applied Catalysis A - General},
	volume = {289},
	number = {2},
	year = {2005},
	month = {AUG},
	pages = {128-134},
	publisher = {ELSEVIER SCIENCE BV},
	address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS},
	abstract = {<p>As-synthesized zeolite-beta exhibits high catalytic activity for the synthesis of cyclic carbonates and alkyl and aryl carbarnates by a phosgene-free route, utilizing the greenhouse effect gas CO2. The reaction occurs with high yields of the desired products at mild conditions and without using any solvent or cocatalyst. Cyclic carbonates are synthesized by cycloaddition reaction Of CO2 with oxiranes (epichlorohydrin, propene oxide, styrene oxide and n-butene oxide) at 393 K and 6.9 bar. Alkyl and aryl carbarnates are synthesized by the reaction of the corresponding amines, CO2 and n-butyl bromide at 353 K and 3.4 bar. The as-synthesized zeolite-beta containing the encapsulated quaternary ammonium ions is not only reusable in several recycling experiments, but also shows superior activity to that of the corresponding homogeneous, quaternary ammonium halide salt generally used in the commercial synthetic practice. The microporous silica (inorganic) acting in concert with the encapsulated organic component constitutes an efficient, recyclable catalyst for this reaction. (c) 2005 Elsevier B.V. All rights reserved.</p>},
	keywords = {alkyl and aryl carbamates, carbon dioxide utilization, cyclic carbonate, phosgene-free synthetic route, Polycarbonate, zeolite-beta},
	issn = {0926-860X},
	doi = {10.1016/j.apcata.2005.04.055},
	author = {Srivastava, R and Srinivas, D and Ratnasamy, P}
}
@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 = {<p>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.</p>},
	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.}
}
