Reactants phenylacetylene

For all catalysts, the hydrogenation mechanism performed under our conditions (liquid phase and low hydrogen pressure) is consistent with an Horiuti-Polanyi mechanism. We found that the phenylacetylene (PhAc) hydrogenation reaction was zero order with respect to hydrocarbon reactants up to 80% of conversion, in agreement with several other studies devoted to the hydrogenation of polyunsaturated compounds." ... 

Benzylideneamino-6-methoxypyridine (35) underwent partially regioselective cyclocondensation with phenylacetylene in the presence of oxidizing agents to afford a separable mixture of 2-methoxy-6,8-diphenyl-1,5-naphthyridine (36) and 6-methoxy-2,4-diphenyl-1,7-naphthyridine (37) (reactants, FeCl3,... 

At low temperatures in acid or ethanolio solution, CuCl adds acetylene to give CuCl C2H2 (63), and (Cu01)3-02112 (164), respectively. These observations are supported by a study of the slow equilibrium between the reactants (271). Addition compounds are formed between CuCl and phenylacetylene or (232),... 

Effects of crystalline structure and acidity differentiate the catalytic behavior of ZSM5, USY and mordenite zeolites. Compounded with the nature of the support, the location of nickel particles leads to very peculiar behaviors in the formation of low-temperature coke during the hydrogenation of phenylacetylene. The principal differences in the high temperature deactivation are determined by the size specificity of the zeolitic supports, and by the high acidity available to the reactant molecules, especially for the USY support. The contribution of nickel to coke formation at low temperatures occurs mainly at the internal surface of Ni/mordenite and Ni/USY and at the external surface of Ni/ZSM-5. This conclusion is supported by the TPR patterns as well as by the relative values of low, intermediate and high temperamre coke for each individual support. 

The reagent catalyzes the reaction of phenylacetylene with triethyl orthoformate to give phenylpropargylaldehyde diethyl acetal. A mixture of the reactants is... 

Data from infrared spectroscopy also support the conclusion that hydride compounds are formed in the co-condensates. For phenylacetylene at 80 K, as for cyclopentadiene, a strong absorption, absent in the spectrum of the reactant hydrocarbon, is observed (at 1380 cm" ). Its intensity increases upon healing the sample to 200 K, just as for cyclopentadiene. At 240 K. a new absorption... 

The activity enhancement effect of copper is much more significant with acetophenone and phenylacetylene than with the other two reactants. This is due presumably to the fact that the chemisorption of acetophenone and phenylacetylene, strongly bonded to the surface, becomes more favourable from the aspects of reaction with the increase of copper content. In the Pd-Cu alloy the number of electrons in the d-band of Pd increases, which invokes a ligand effect decreasing the heat of chemisorption. 

Copper Reactants. Application of the Pd/Cu-catalyzed cross-coupling, the Sonogashira reaction, with monosubstituted or protected acetylene gives rise to a variety of ethynyl-heteroarenes (Schenae 27). Reactions with trimethylsilylacetylene or phenylacetylene in... 

The rate of hydrobromination of PhC=CH in 90% AcOH at initial concentrations of 0.1 -1.0 M can be described by third-order (time) and first-order (concentrations) reaction equations with respect to the alkyne. The dependence of on the initial reactant concentration passes through a minimum, which is always present when the ionic strength fi of the solution is maintained at 1.1, and is due to the participation in the reaction of several types of species formed by HBr. From the dependence of on the degree of dissociation of HBr ion pairs by the Acree equation, the /cion was estimated at 1 x 10 1 moH s. Since HBr ion pairs do not react with phenylacetylene, the authors proposed that, at high concentrations, the reaction involves hydrogen bromide dimers. ... 

The formation of the pyridine ring, observed in this cases, implies the interception of iminoaldehyde (intermediate G) by phenylacetylene and represents an additional experimental support of the ketoxime-acetylene mechanism of pyrrole synthesis that is presently accepted. On the other hand, this new direction of the reaction of ketoximes with acetylene, despite moderate yields of pyridylpyrroles, can have preparative value as straightforward one-pot synthesis of the unnatural nicotine-like alkaloid from simple available starting reactants (1,2-dioximes and acetylene). 

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