A New Reaction of Bisphenol A and Preparation of Polysubstituted 9,9-Dimethylxanthenes
摘要:
A new transformation of bisphenol A (1) to polymethylated 9,9-dimethylxanthenes 2-5 in the presence of an exogenous phenol is described. The reaction proceeds with concurrent liberation of phenol, is catalyzed by strong acid, and takes place at synthetically useful rates at temperatures above 100 degrees C. Materials chemically related to bisphenol A polycarbonate 10, chroman fl, and tars generated during the manufacture of 1, behave similarly. The product xanthenes are useful as precursors to novel xanthene polyesters such as 33 having high glass transition temperatures relative to analogous materials based on 12 or 13. Catalytic oxidation of xanthenes 2-4 affords highly insoluble diacids that are esterified to the esters 6-8. A mechanistic framework accounting for the appearance of chroman 23 and spiroketal 24 as intermediates is given. Overall, the reaction has the characteristics of a complex series of equilibria in which xanthenes such as 2 are strongly favored.
A dinuclear Ni complex with a double‐decker structure (see scheme) and a short Ni–Ni distance promotes the copolymerization of ethylene with functional monomers. Matching of the Ni–Ni distance with the co‐monomer structure resulted in polymers containing a high density of the co‐monomer unit.
A strategy for preparing spirobichroman dianhydride from bisphenol A and its resulting polyimide with low dielectric characteristic
作者:I Chun Tang、Meng Wei Wang、Chien Hsin Wu、Shenghong A. Dai、Ru Jong Jeng、Ching Hsuan Lin
DOI:10.1039/c6ra25648a
日期:——
The high performance polyimide, SBC-DDM, exhibits a large free volume, leading to outstanding organo-solubility and a low dielectric constant.
高性能聚酰亚胺SBC-DDM具有大的自由体积,导致出色的有机溶解性和低介电常数。
Method for making polyalkylated xanthenes
申请人:General Electric Company
公开号:US05554770A1
公开(公告)日:1996-09-10
Polyalkylated xanthenes are prepared by effecting reaction between an alkylated phenol such as m-cresol and an oxygenated organic material such as acetone in the presence of an acid catalyst such as methanesulfonic acid.
Method for recovering phenol and xanthene values from waste polycarbonate
申请人:GENERAL ELECTRIC COMPANY
公开号:EP0738702A1
公开(公告)日:1996-10-23
Organic values are salvaged from scrap polycarbonate by heating in the presence of an acid catalyst and a C1-4 alkyl phenol such as m- or p-cresol. Among the compounds which can be salvaged are polyalkylated xanthenes, phenol and diaryl carbonate.