Influence of Temperature and Pressure on Cyclic Carbonate Synthesis Catalyzed by Bimetallic Aluminum Complexes and Application to Overall syn-Bis-hydroxylation of Alkenes

Abstract

The effect of moderate temperatures (22-100 °C) and pressures (1-10 bar) on the synthesis of cyclic carbonates from epoxides and carbon dioxide catalyzed by a combination of bimetallic aluminum complexes and tetrabutylammonium bromide is investigated. The combined bimetallic complex and tetrabutylammonium bromide catalyst system is shown to be an order of magnitude more active than the use of tetrabutylammonium bromide alone at all temperatures and pressures studied. At the higher temperatures and pressures used, disubstituted epoxides become substrates for the reaction and it is shown that reactions proceed with retention of the epoxide stereochemistry. This allowed a route for the overall syn-bis-hydroxylation of alkenes to be developed without the use of hazardous metal based reagents. At higher pressures it is also possible to use compressed air as the carbon dioxide source.

Highly efficient conversion of CO2 at atmospheric pressure to cyclic carbonates with in situ-generated homogeneous catalysts from a copper-containing coordination polymer

“…2). On the other hand, the addition of BIT-C greatly promotes the conversion of 1,2-epoxyhexane, compared to the case with Bu 4 NBr alone, which is consistent with the previous reports [22]. As a comparison, copper nitrate (Cu(NO 3 ) 2 ), copper chloride (CuCl 2 ), and copper acetate (Cu(Ac) 2 ) were used as homogeneous catalysts as well (Fig.…”

“…11). This means that the (CuL) 2 -catalyzed cycloaddition of CO 2 and PO is essentially different from the mechanism proposed in the bimetallic aluminum (salen) catalytic systems [17,22,41].…”

“…This is more appealing and also challenging. Recently, an attempt of using the compressed air as CO 2 source under the pressurized conditions has been reported [22]. In our test, clean air (bubbled by an air pump through a filter and a dying tube), replacing atmospheric pressure pure CO 2 , was used in the BIT-C-catalyzed cycloaddition of phenyl glycidyl ether.…”

Recent Advances in the Catalytic Preparation of Cyclic Organic Carbonates

“…56 In this case, starting from diastereo-pure internal epoxide isomers (cis or trans) the corresponding Since the overall configuration is retained in the hydrolysis step, CO 2 can be exploited as a temporary protecting group to afford cis-diols. h, THA-Cr-Si-POM = TBAB = 2 mol%), since the POM catalyst is readily soluble in the mixture of epoxide substrate, COC product and scCO 2 .…”

Development of a Halide‐Free Aluminium‐Based Catalyst for the Synthesis of Cyclic Carbonates from Epoxides and Carbon Dioxide

“…[10] We previously studied qualitatively the influence of temperature (25-100 8C) and pressure (1-10 bar) on cyclic carbonate synthesis catalysed by bimetallic aluminium complexes such as 4 and tetrabutylammonium bromide. [11] Here, we report the results of a detailed kinetic study of the synthesis of glycerol carbonate 3 g at temperatures of 25-100 8C and carbon dioxide pressures of 1-100 bar using a combination of complex 4 and tetrabutylammonium bromide as catalyst which have given new insights into the reaction pathway and led to the discovery that complex 4 can catalyse the reaction without a co-catalyst.…”