Efficient Transesterification Preparation of Polycarbonate Diol with High Molecular Weight Using TiO2/SiO2 Solid Acid Catalysts.

A series of TiO2/SiO2 catalysts were prepared by hydrolysis and used in the transesterification of diphenyl carbonate (DPC) and 1,4‐butanediol (BDO) to produce polycarbonate diol (PCDL). The physical properties of TiO2/SiO2 solid acid catalysts were characterized, and the relationship between their structural features and catalytic transesterification reaction was analyzed. The effects of various reaction conditions such as hydrolysis procedure, transesterification temperature, catalyst amount, and the mole ratio of the starting materials on the catalytic synthesis of PCDL were investigated. The maximum catalytic activity was based on the TiO2 : SiO2=3 : 1 with hydrolysis procedure of adding the Ti/Si mixture (A) to deionized water and anhydrous ethanol (B). The as‐synthesized TiO2/SiO2‐A‐to‐B catalyst exhibits rough surface with the average pore size of 6.75 nm, and the total acid amount of 1.07 mmol/g. The PCDL yield of transesterification reached 89.8 %, and the number average molecular weight reached 9074 g/mol under the optimal reaction conditions, and the molecular weight of the PCDL product could be adjusted. [ABSTRACT FROM AUTHOR]