Comparison of polycarbonate precursors synthesized from catalytic reactions of bisphenol‐A with diphenyl carbonate, dimethyl carbonate, or carbon monoxide

Abstract

Transesterification of bisphenol-A with diphenyl carbonate or dimethyl carbonate, and direct oxidative carbonylation of bisphenol-A were compared to obtain polycarbonate precursors for phosgene-free polycarbonate synthesis. The melt-transesterification of bisphenol-A and diphenyl carbonate occurred readily to produce reactive precursors without a significant equilibrium constraint. On the other hand, the transesterification of bisphenol-A and dimethyl carbonate showed a serious equilibrium limitation in obtaining reactive polycarbonate precursors leading to high molecular weight polymers, and coproduced a significant amount of methylated bisphenol-A. The direct oxidative carbonylation of bisphenol-A with CO produced diphenolic-ended oligomers and a significant amount of by-products, which are the least reactive in the subsequent polycondensation step of the phosgene-free polycarbonate process. A novel method to synthesize the reactive polycarbonate precursors was proposed that employed the coupled oxidative carbonylation of both bisphenol-A and phenol.

Synthesis of hyperbranched polycarbonate by novel polymerization of di-tert-butyl tricarbonate with 1,1,1-tris(4-hydroxyphenyl)ethane

“…1 H NMR spectra (500 and 600 MHz) were obtained using JEOL JNM-ECA-600 and JEOL JNM-ECA-500 spectrometers (JEOL, Tokyo, Japan) using chloroform-d (CDCl 3 6 ). Typical 1D FID was subjected to exponential multiplication with an exponent of 0.1 Hz (for 1 H) and 1.0-2.0 Hz (for 13 C).…”

“…Each model compound (Scheme 3), which was synthesized separately, was also investigated by 1 H NMR in DMSO-d 6 and showed a similar resonance for the methyl protons at 2.132, 2.071 and 2.012 p.p.m. for branching, linear and terminal units, respectively.…”

“…3 In recent years, there has been an increasing demand for a safe and environmentally friendly process to synthesize PC. [4][5][6][7][8][9] PC has the disadvantage of having a high melt viscosity (low liquidity) and significant orientational birefringence caused by the Bisphenol-A backbone in the main chain. To solve these problems, there are a few applicable approaches, such as using relatively low molecular weight PC, introducing a different backbone into PC 10 and making a polymer alloy or blends with additives that cancel the intrinsic birefringence of PC.…”

Carbon Dioxide Fixation into Organic Compounds

“…[43] Either DPC or DMC were used. The molecular carbonates react in presence of basic catalysts (oxides, hydroxides or phenolates of Group 1 and 2 elements), Lewis acids; organotin (dibutyltin oxide) and organotitanium compounds, phosphonium phenolate or borohydride, tetramethylammonium hydroxide.…”

Excellent performance of TiO 2 (B) nanotubes in selective transesterification of DMC with phenol derivatives

“…The catalysts of PC synthesis from DMC included TiO 2 /SBA-15 [22], TiO 2 /SiO 2 [23] and (Bu 2 SnCl) 2 O [21]. Haba et al [21] reported that the homogeneous catalyst has high catalytic activity for PC synthesis, but the separation of homogeneous catalyst from products was complicated.…”