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6910476 
Journal Article 
Revealing the catalytic mechanism of an ionic liquid with an isotope exchange method 
Sun Xuewen; Zhao Suoqi; , 
2011 
1 
Petroleum Science
ISSN: 1672-5107
EISSN: 1995-8226 
SPRINGER 
NEW YORK 
8 
4 
495-501 
English 
WOS:000297563800017 
The alkylation mechanism catalyzed by an ionic liquid (as a Lewis acid) may be different from the traditional alkylation mechanism catalyzed by Bronsted acid, especially as their initiation steps are still not clear. In this paper, an isotope exchange method is used to investigate the catalytic mechanism of AlCl3/butyl-methyl-imidazolium chloride ionic liquid in the alkylation of benzene with 1-dodecene. The proposed catalytic mechanism was confirmed by analysis of ionic liquid before and after reaction and of the alkylation products of deuterated benzene (C6D6) with 1-dodecene. The proposed mechanism consists of the equilibrium reaction between [Al2Cl7](-)+H+ and [AlHCl3](+)+[AlCl4](-), in which the Bronsted acid [AlHCl3](+) is supplied by the reaction of 2-H on the imidazolium ring and [Al2Cl7](-). The alkylation reaction is initiated by the Bronsted acid [AlHCl3](+) which reacts with 1-dodecene to form a carbonium ion, then the carbonium ion reacts with benzene to form an unstable sigma complex, leading to the formation of 2-phenyldodecane.