High activity metal carbene metathesis catalysts generated using a thermally activated N-heterocyclic carbene precursor
申请人:——
公开号:US20030083445A1
公开(公告)日:2003-05-01
The invention provides a method for converting a less active or slower to initiate system to a higher activity system so that at the end of a polymerization the most active species is present in the system. The invention generally relates to a process for converting a less active or slower to initiate catalyst system to a higher activity catalyst system wherein the process comprises contacting a protected N-heterocyclic carbene with a metathesis catalyst and an olefin in the presence of energy. One of the benefits of the invention is that the amount of catalyst required is less than or lowered in the presence of the protected N-heterocyclic carbene as compared to the amount of catalyst required in the absence of the protected N-heterocyclic carbene. The protected N-heterocyclic carbene can be unsaturated or saturated. In addition, the invention describes novel ruthenium initiators and methods of making the same.
A novel method for producing methionine without using hydrogen cyanide as a raw material has been demanded. A method for producing methionine including a step A of oxidizing 4-methylthio-2-oxo-1-butanal in the presence of an alcohol; a step B of hydrolyzing a 4-methylthio-2-oxo-butanoic acid ester obtained in the step A; and a step C of subjecting 4-methylthio-2-oxo-butanoic acid obtained in the step B to reductive amination.
PROCESS FOR PRODUCING ALPHA-HYDROXYKETONE COMPOUND
申请人:Hagiya Koji
公开号:US20110178309A1
公开(公告)日:2011-07-21
A process for producing an α-hydroxyketone compound, which comprises subjecting an aldehyde compound to a coupling reaction in the presence of an alkoxyimidazolidine compound represented by the formula (1) wherein R
1? and R
2? independently represent a hydrogen atom, etc., R
3? and R
4? independently represent a substituted or unsubstituted aryl group, etc. and R
5? represents an alkyl group.
A curable composition comprises (a) at least one polyorganosiloxane, fluorinated polyorganosiloxane, or combination thereof comprising reactive silane functionality comprising at least two hydroxysilyl moieties; (b) at least one polyorganosiloxane, fluorinated polyorganosiloxane, or combination thereof comprising reactive silane functionality comprising at least two hydrosilyl moieties; and (c) a catalyst composition comprising at least one carbene; wherein at least one of the components (a) and (b) has an average reactive silane functionality of at least three.