Comparison between phosphine and NHC-modified Pd catalysts in the telomerization of butadiene with methanol – A kinetic study combined with model-based experimental analysis
摘要:
The telomerization of butadiene with methanol was investigated in the presence of different palladium catalysts modified either with triphenylphosphine (TPP) or 1,3-dimesityl-imidazol-2-ylidene (IMes) ligand. When pure butadiene was used as substrate, a moderate selectivity for the Pd-TPP catalyst toward the desired product 1-methoxy-2,7-octadiene (1-Mode) of around 87% was obtained, while the IMes carbene ligand almost exclusively formed 1-Mode with 97.5% selectivity. The selectivity remained unchanged when the pure butadiene feed was replaced by synthetic crack-C-4 (sCC(4)), a technical feed of 45 mol% butadiene and 55 mol% inerts (butenes and butanes). The TPP-modified catalyst showed a lower reaction rate, which was attributed to the expected dilution effect caused by the inerts. Surprisingly, the IMes-modified catalyst showed a higher rate with sCC(4) compared to the pure feed. By means of a model-based experimental analysis, kinetic rate equations could be derived. The kinetic modeling supports the assumption that the two catalyst systems follow different kinetic rate equations. For the Pd-TPP catalyst, the reaction kinetics were related to the Jolly mechanism. In contrast, the Jolly mechanism had to be adapted for the Pd-IMes catalyst as the impact of the base seems to differ strongly from that for the Pd-TPP catalyst. The Pd-IMes system was found to be zero order in butadiene at moderate to high butadiene concentrations and first order in base while the nucleophilicity of the base is influenced by the methanol amount resulting in a negative reaction order for methanol. (C) 2015 Elsevier Inc. All rights reserved.
The present invention relates to a (meth)acrylate monomer of the general formula (I)
in which R
1
is hydrogen or a methyl group, X is oxygen or a group of the formula NR′ in which R′ is hydrogen or a radical having 1 to 6 carbon atoms, R
2
is an alkylene group having 1 to 22 carbon atoms, Y is oxygen, sulphur or a group of the formula NR″, in which R″ represents hydrogen or a radical having 1 to 6 carbon atoms, and R
3
is an unsaturated radical having 8 carbon atoms and at least two double bonds.
The present invention further relates to a process for preparing the monomers set out above, to polymers obtainable from this monomer mixture, and to coating materials which comprise the stated polymers.
[DE] ZUSAMMENSETZUNG ZUR HERSTELLUNG VON POLYMEREN, (METH)ACRYL-POLYMER, BESCHICHTUNGSMITTEL UND BESCHICHTUNG<br/>[EN] COMPOSITION FOR PRODUCING POLYMERS, (METH)ACRYLIC POLYMER, COATING AGENT, AND COATING<br/>[FR] COMPOSITION POUR LA PRÉPARATION DE POLYMÈRES, (MÉTH)ACRYL-POLYMÈRE, AGENT DE REVÊTEMENT ET REVÊTEMENT
申请人:EVONIK ROEHM GMBH
公开号:WO2012004160A1
公开(公告)日:2012-01-12
Die vorliegende Erfindung betrifft eine Zusammensetzung zur Herstellung von Polymeren umfassend mindestens ein Monomer und mindestens einen Radikalstarter, wobei der Radikalstarter eine Azoverbindung ist, mindestens ein Monomer ein Amid- oder ein Amin-Monomer ist, und mindestens ein Monomer ein (Meth)acryl-Monomer ist, das im Alkylrest mindestens eine C-C-Doppelbindung und 8 bis 40 Kohlenstoffatome aufweist. Darüber hinaus beschreibt die vorliegende Erfindung ein (Meth)acrylpolymer, welches aus der zuvor dargelegten Zusammensetzung erhalten werden kann, und ein Beschichtungsmittel. Ferner beschreibt die vorliegende Erfindung eine Beschichtung.
A Simple Halide-to-Anion Exchange Method for Heteroaromatic Salts and Ionic Liquids
A broad and simple method permitted halide ions in quaternary heteroaromatic and ammonium salts to be exchanged for a variety of anions using an anion exchange resin (A− form) in non-aqueous media. The anion loading of the AER (OH− form) was examined using two different anion sources, acids or ammonium salts, and changing the polarity of the solvents. The AER (A− form) method in organic solvents was