The present invention discloses a process for preparing 4-aminodiphenylamine, which process uses nitrobenzene and aniline as raw materials, a complex base catalyst as condensation catalyst and a powdery composite catalyst as hydrogenation catalyst, and comprises five process stages: condensation; separation I; hydrogenation; separation II; and refining. The process can be continuously carried out. By selecting a complex base catalyst to catalyze the condensation reaction and separating it prior to the hydrogenation, the problem that the complex base catalysts thermally decompose in the hydrogenation reaction is avoided, the selectable range of hydrogenation catalysts is largely enlarged so that it is possible to select cheaper hydrogenation catalyst, and the selection of production process and equipment is easier and further industrialization is easier. The complex base catalysts used in the present invention are inexpensive and have higher catalytic activity. The process can be carried out at mild conditions and can adapt to broad range of water content, by-product is less and conversion and selectivity are higher. The operational strength is low, no corrosive liquid is produced, and environment pollution is reduced. The purity of 4-aminodiphenylamine prepared can exceed 99 wt.-%, and the yield in the industrial production process can be over 95%.
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.
Highly Selective Ortho‐Directed Dicarboxylation of Cyclopentadiene by Methylcarbonates and CO
<sub>2</sub>
or COS – First Insight into Co‐ordination Chemistry of New Ambident Ligands
作者:Tobias Vollgraff、Jörg Sundermeyer
DOI:10.1002/chem.202100300
日期:2021.6.10
mechanism where the acidicproton of the monocarboxylic acid intermediate plays an ortho-directing and CO2 activating role for the second kinetically accelerated CO2 addition step exclusively in ortho position. The same and related thiocarboxylates [Cat]2[C5H3(COS)2H] are obtained by reaction of COS with Cat[Cp] (Cat=NR4+, PR4+, Im+). A preliminary study on [Cat]2[C5H3(CO2)2H] reveals, that its soft and hard
CROSSLINKABLE COMPOSITION CROSSLINKABLE WITH A LATENT BASE CATALYST
申请人:Brinkhuis Richard Hendrikus Gerrit
公开号:US20130041091A1
公开(公告)日:2013-02-14
The present invention relates to a crosslinkable composition comprising at least one crosslinkable component crosslinkable by a latent base crosslinking catalyst comprising a substituted carbonate salt according to formula 1 wherein X
+
represents a cation and wherein R is hydrogen, alkyl, aryl or aralkyl group, and wherein the crosslinkable composition comprises 0.1-10 wt %, preferably 0.1-5, more preferably 0.2-3 and most preferably 0.5-1.5 wt % water (relative to total weight of the crosslinkable composition). The invention further relates to a coating composition comprising the crosslinkable composition according to the invention, a novel catalyst composition and to the use of said catalyst composition according to the invention as a latent base crosslinking catalyst in coating compositions, preferably in RMA crosslinkable compositions.
A process for producing quaternary salts of high purity is disclosed, comprising reacting a tertiary amine or phosphine with a carbonic acid diester to form a corresponding quaternary carbonate and further mixing it with an acid to perform decarboxylation. The quaternary salts thus obtained are useful compounds which can be used in wide fields as various catalysts, electrolytes, additives, medicaments, etc.