Synthesis of cyclic carbonates from carbon dioxide and epoxides using alkali metal halide supported liquid phase catalys

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Catalysis Letters Vol. 112, Nos. 1–2, November 2006 (Ó 2006) DOI: 10.1007/s10562-006-0163-2

Synthesis of cyclic carbonates from carbon dioxide and epoxides using alkali metal halide supported liquid phase catalyst Sachin R. Jagtap,* Mayur J. Bhanushali, Anil G. Panda, and Bhalchandra M. Bhanage Department of Chemistry, Institute of Chemical Technology, N. Parekh Marg, Matunga, Mumbai 400 019, India

Received 11 May 2006; accepted 10 August 2006

Supported liquid phase catalysts (SLPC) were prepared from high surface area porous silica, polyethylene glycol (PEG), alkali metal halides and used for the synthesis of cyclic carbonates from carbon dioxide and epoxides. These catalysts was found to be highly active and selective for the synthesis of cyclic carbonates. The catalytic activity strongly depends on the nature of the supported alkali metal halide. The amount of alkali metal salt incorporated in the catalyst is one of the most important factor governing the catalytic performance. Effect of various reaction parameters such as pressure, temperature, catalyst loading, surface area of support was also studied in detail. KEY WORDS: cyclic carbonates; supported liquid phase catalyst (SLPC); alkali metal halides; carbon dioxide fixation; oxiranes; silica.

1. Introduction Carbon dioxide is one of the green house gas arising from human activities, which leads to environmental pollution. In recent years considerable attention is given for development of environmentally benign processes based on chemical fixation of carbon dioxide [1]. Several methodologies are developed for chemical fixation of carbon dioxide to valuable chemicals [2] and the synthesis of five membered cyclic carbonates via, the cycloaddition of CO2 to epoxides is one of the promising reactions in this direction replacing existing poisonous phosgene based synthesis. The five membered cyclic carbonates have several application such as they act as a precursor for polycarbonates and other polymeric materials [3] they are also used as an intermediate for glycol, carbamates, pyrimidines, purines and so on [4]. In recent decades numerous homogenous and heterogeneous catalyst system such as alkali metal salts alone [5] or in combination with crown ether [6], quaternary ammonium salt or phosponium salt [7,8] ionic liquids [9], halostannanes [10] other organic bases [11–13], mixed oxides [14–17] smectite [18,19], zeolite [20,21] titanosilicates[22], metal complexes [23–29], and have been explored for this transformation. Most of these systems suffer from the problems associated with low catalyst reactivity, catalyst/product separation, expensive catalysts, sophisticated techniques and lower yield of the products. Hence there is a need for development of a highly active and recyclable catalyst system.

*To whom correspondence should be addressed.

Various soluble alkali metal halides [30] are reported as a catalyst for the synthesis of cyclic carbonates. The catalyst product separation was the major disadvantage with this system due to homogenous nature of the catalyst