Study On The Synthesis Of Cyclic Carbonates

Cyclic carbonates, as one of products of CO2 chemistry, are attractive and important compounds in a variety of chemical research fields, such as polar aprotic solvent, intermediate in organic synthesis, precursors for polymeric materials such as polycarbonates。This thesis aims at the studies on the asymmetric synthesis and multi-component synthesis of cyclic carbonate, which consists of the following four chapters.Chapter 1:The application and synthesis of cyclic carbonate are reviewed, and the development in the green synthesis of cyclic carbonate via CO2 cycloaddition to epoxide is briefly introducted. The design and application of polymer catalyst on the asymmetric synthesis also are concluded in this chapter.Chapter 2:Based on the concept of "one-phase catalysis and two-phase separation", we developed four new polymer BINOL-Salen-Co (III)X catalysts with an auxiliary chiral site, and problems encountered in the synthesis of the catalyst are presented and discussed in detail.Chapter 3:Four new chiral polymers of BINOL-Salen-cobalt (III) salt complexes have been applied to the direct fabrication of chiral propylene carbonate from racemic propylene oxide and the hydrolytic kinetic resolution of racemic propylene. The experiment investigated the effect of different chiral catalyst, co-catalyst, counterious, reaction temperature in chiral cyclic carbonate formation. The chirality of the BINOL fragment has an important influence on the optical selectivity of Salen-Co(III)X complexes. The catalysts could be readily recovered and be repeatedly used without loss of either activity or enantioselectivity.Chapter 4:Inspired by the mechanism of the Darzens reaction and based on mechanism considerations of cyclic carbonate synthesis, we design a three-component cyclization reaction for polysubstituted cyclic carbonate synthesis in a single operation from phenacyl bromide, CO2, and aldehyde using LDA as a base. The experiment investigated the effect of base, solvent, reaction temperature, substrate on the selection and yield of cyclic carbonate formation. This novel, efficient synthesis of polysubstituted cyclic carbonates was achieved under mild conditions (1 atm,35℃) in reasonable yields with a reaction time of only ten minutes.