THE CO-CYCLOTRIMERIZATION OF HEXYNES AND PHENYLACETYLENE WITH NIOBIUM(V) CHLORIDE AS CATALYST

被引:13
作者
DUPLESSIS, JAK
VILJOEN, JS
DUTOIT, CJ
机构
[1] Department of Chemistry, Potchefstroom University for CHE, Potchefstroom
来源
JOURNAL OF MOLECULAR CATALYSIS | 1991年 / 64卷 / 03期
关键词
D O I
10.1016/0304-5102(91)85136-P
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Various alkynes were cyclotrimerized with NbCl5 as catalyst and C2H5AlCl2 as co-catalyst at an Al/Nb molar ratio = 2 in CCl4 at room temperature and pressure. The tendency of the alkynes to cyclotrimerize decreased in the following order: phenylacetylene > hex-1-yne > hex-2-yne approximately hex-3-yne approximately oct-4-yne. If phenylacetylene (X) was co-cyclotrimerized with another alkyne (Y), four different cyclotrimers were found, as represented by the following equation: X + Y --> X3 + X2Y + XY2 + Y3. If the amount of cyclotrimers formed is plotted against the phenylacetylene mole fraction, a statistically random distribution of the products is observed. Differences with regard to the ideal random case are attributed to a polymerization reaction. During the cyclotrimerization process there is therefore a statistically random coordination of the alkynes on the catalytic species, after which ring closure occurs to form the cyclotrimeric products.
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页码:269 / 275
页数:7
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