Catalytic acylation of benzoxazolin-2-ones in the presence of zinc chloride

In the acylation of benzoxazolin-2-ones by aromatic acid chlorides in the presence of 10^-2 mole of ZnCl₂, the yields of the corresponding 6-aroylbenzoxazolin-2-ones depend on the electronegativity of the acylating agent and the nucleophilicity of the benzoxazolin-2-ones.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1136–1138, August, 1994.     

Spectrophotometric determination of aluminium with Chromal Blue G in the presence of cetyltrimethylammonium chloride

Summary Spectrophotometric Determination of Aluminium with Chromal Blue G in the Presence of Cetyltrimethylammonium Chloride Chromal Blue G (C. I. 43835) in the presence of cetyltrimethylammonium chloride is proposed for the spectrophotometric determination of microgram amounts of aluminium. The stoichiometric ratio of aluminium to Chromal Blue G is 14. Beer's law is obeyed from 0.01 to 0.16 ppm of aluminium. The molar absorptivity is 1.62×10⁵1·mole^–1·cm^–1 at 660 nm.     

Catalytic isomerization of dihalobenzenes C6H3X2R in the presence of high-silica zeolites

Catalytic isomerization of dichloro- and difluorobenzenes was carried out under conditions of a gas-phase reaction occurring in the presence of metallosilicates with the pentasil-type zeolite structure, in which several silicon atoms are isomorphically replaced by Al, Ga, or Fe atoms. A correlation between the acid properties of these zeolites and their ability to induce dihalobenzene isomerization was found.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1920–1922, November, 1994.     

CIS-trans isomerization of nitrostilbenes in the presence of aromatic amines

Conclusions The possible mechanisms for the cis-trans isomerization of nitrostilbenes in the presence of aromatic amines were discussed and it was shown that the reason for the isomerization is the formation of charge-transfer complexes.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1602–1605, July, 1980.     

Catalytic isomerization of allylbenzene on organomagnesium clusters

Catalytic isomerization of allylbenzene to form trans-β-methylstyrene quantitatively occurs on the magnesium-anthracene cluster adduct under mild conditions. A low-stability organomagnesium compound, presumably of the cluster nature and active in catalytic allylbenzene isomerization, is formed by cocondensation of magnesium and allylbenzene vapors at the liquid nitrogen temperature. The products of low-temperature solid-phase reactions of magnesium with hydrocarbons containing aromatic rings exhibit high catalytic activity in the allyl isomerization of allylbenzene. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1155–1158, May, 2005.     

The kinetics of the aluminium bromide catalyzed isomerization of 1-propyl bromide

An analysis of the initial rates of reaction was carried out of the aluminium bromide catalyzed isomerization of 1-propyl bromide: 1-C₃H₇Br + Al₂Br₆ = 2-C₃H₇Br + Al₂Br₆ The proposed kinetics of the process is consistent with a nucleophilic displacement of the aliphatic bromine contained in complexes of the alkyl bromide with aluminium bromide. The displacement, initiated by the AlBr₄⁻ ion, is accompanied by a rate determining 2,1 hydride shift.     

Catalytic isomerization of olefins on BeO, I

The catalytic activity of BeO for the double bond shift of 1-pentene has been investigated. The maximum activity was exhibited by samples calcined at 1173 K. The effect of pyridine, CO₂ and CCl₄ on the activity was also studied. Lewis acid-base site pairs appear to be active for the isomerization.

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BeO 1- . , 1173 . , CO₂ CCl₄ . - .

     

Catalytic isomerization of 1-hexene on hy zeolite

The isomerization of 1-hexene on 70/80 mesh HY zeolite was studied at 200°C. The observed reaction products are formed via a variety of processes including double bond shift, cis–trans isomerization, skeletal rearrangement, cracking, hydrogen transfer, polymerization, cyclization, and coke formation. By applying the time-on-stream theory, the products have been classified as primary, secondary, or both, according to their OPE curves on product selectivity plots. 2-Ethyl-1-butene, which is present as an impurity in the feed, is found to react about 30 times faster than 1-hexene. Both 2-hexenes and 3 hexenes are formed primarily from 1-hexene, while 3 methyl 2 pentenes and 3-methyl-1-pentene formed from 2-ethyl-1-butene. The ratio of the initial rate of deprotonation to that of hydrogen shift in these reactions is ～15 and ～100, respectively. All products of skeletal rearrangement are observed to be secondary. Cracking products are produced mainly from precoke, which is also the source of hydrogen in the formation of paraffins. A detailed reaction network along with its associated mechanisms are presented and discussed.     

Catalytic isomerization of olefins on molybdena, I

The catalytic activity of MoO₃ calcined at different temperatures was investigated for the double bond shift isomerization of 1-pentene. Carbon dioxide has no effect, whereas pyridine can totally poison the activity. Brönsted acidic surface hydroxy groups seem to be the principal active sites for isomerization.

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MoO₃, , 1- . - , . .

     

Catalytic decarboxylation of chloronitroacetyl chloride

Conclusions The catalytic decarboxylation of chloronitroacetyl chloride by various acid and base catalysts leads to dichloroformoxime. A mechanism was proposed involving intramolecular oxidative-reductive decarboxylation.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 934–937, April, 1986.The authors express their gratitude to A. V. Yarkov for assistance in taking and interpreting the IR spectra.