Amide/Iminium Zwitterionic Catalysts for (Trans)esterification: Application in Biodiesel Synthesis
作者:Ying-Pong Lam、Xinyan Wang、Fei Tan、Wing-Hin Ng、Ying-Lung Steve Tse、Ying-Yeung Yeung
DOI:10.1021/acscatal.9b01959
日期:2019.9.6
organocatalysts based on an amide anion/iminium cation charge pair has been developed. The zwitterions are easily prepared by reacting aziridines with aminopyridines. They are catalytically applicable to transesterifications and dehydrative esterifications. Mechanistic studies reveal that the amide anion and iminium cation work synergistically in activating the reaction partners, with the iminium cationic
ZWITTERIONIC CATALYSTS FOR (TRANS)ESTERIFICATION: APPLICATION IN FLUOROINDOLE-DERIVATIVES AND BIODIESEL SYNTHESIS
申请人:The Chinese University of Hong Kong
公开号:US20210023539A1
公开(公告)日:2021-01-28
An amide/iminium zwitterion catalyst has a catalyst pocket size that promotes transesterification and dehydrative esterification. The amide/iminium zwitterions are easily prepared by reacting aziridines with aminopyridines. The reaction can be applied a wide variety of esterification processes including the large-scale synthesis of biodiesel. The amide/iminium zwitterions allow the avoidance of strongly basic or acidic condition and avoidance of metal contamination in the products. Reactions are carried out at ambient or only modestly elevated temperatures. The amide/iminium zwitterion catalyst is easily recycled and reactions proceed in high to quantitative yields.
Photoimageable compositions having improved chemical resistance and stripping ability
申请人:Shipley Company LLC
公开号:EP1008912A1
公开(公告)日:2000-06-14
A negative-acting photoimageable composition useful as a primary imaging resist in the manufacture of printed circuit boards comprises an acid-functional binder polymer, a photopolymerizable component, and a photoinitiator chemical system, in which the binder polymer has an anhydride functional backbone half-esterified with a meth(acrylate) functional hydroxy-terminated oligomer, wherein the meth(acrylate) functionality is separated from the half-ester linkage by at least two alkoxylate groups and at least one ring opened lactone group for improved stripping ability in strong alkaline aqueous stripping solutions, while maintaining good chemical resistance to other processing chemicals, such as alkaline developing solutions, acid etching solutions, and acid plating baths.
Photoimageable compositions having improved stripping ability and resolution
申请人:Shipley Company LLC
公开号:EP1008910A1
公开(公告)日:2000-06-14
A negative-acting photoimageable composition useful as a primary imaging resist in the manufacture of printed circuit boards comprises an acid-functional binder polymer, a photopolymerizable component, and a photoinitiator chemical system, in which all or a portion of the photopolymerizable component comprises a (meth)acrylate functional urethane oligomer, wherein the (meth)acrylate functionality is separated from the urethane linkage by at least two alkylene oxide groups and at least one ring-opened lactone group for improved flexibility, tenting strength, fine line adhesion, developer scumming, coupled with unexpectedly improved resistance to processing chemicals, such as alkaline developing solutions, acid etching solutions, and acid plating baths, and stripping ability in strong alkaline aqueous stripping solutions. The acid-functional binder polymer has a low molecular weight and does not contain styrene, contributing to stripping ability and improved resolution.
Photoimageable compositions having improved flexibility and stripping ability
申请人:Shipley Company LLC
公开号:EP1008911A1
公开(公告)日:2000-06-14
A negative-acting photoimageable composition useful as a primary imaging resist in the manufacture of printed circuit boards comprises an acid-functional binder polymer, a photopolymerizable component, and a photoinitiator chemical system, in which all or a portion of the photopolymerizable component comprises a (meth)acrylate functional urethane oligomer, wherein the (meth)acrylate functionality is separated from the urethane linkage by at least two alkylene oxide groups and at least one ring-opened lactone group for improved flexibility, tenting strength, fine line adhesion, developer scumming, coupled with unexpectedly improved resistance to processing chemicals, such as alkaline developing solutions, acid etching solutions, and acid plating baths, and stripping ability in strong alkaline aqueous stripping solutions.