02099nas a2200241   4500008004100000022001400041245016700055210006900222260007300291300001200364490000800376520114000384653003001524653003101554653002101585653003401606653001801640653001701658100001801675700001601693700001701709856013101726       2005                        eng d  a0926-860X00aZeolite-based organic-inorganic hybrid catalysts for phosgene-free and solvent-free synthesis of cyclic carbonates and carbamates at mild conditions utilizing CO20 aZeolitebased organicinorganic hybrid catalysts for phosgenefree   aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcAUG  a128-1340 v2893 a<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>10aalkyl and aryl carbamates10acarbon dioxide utilization10acyclic carbonate10aphosgene-free synthetic route10aPolycarbonate10azeolite-beta1 aSrivastava, R1 aSrinivas, D1 aRatnasamy, P  uhttps://library.ncl.res.in/content/zeolite-based-organic-inorganic-hybrid-catalysts-phosgene-free-and-solvent-free-synthesis-0