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IONIC LIQUIDS AS A CLEAN CATALYST FOR THE ALKYLATION OF ISOBUTANE WITH 2-BUTENE
Citation:
Varma*, R S., V Namboodiri**, K. Yoo, AND P. G. Smirniotis. IONIC LIQUIDS AS A CLEAN CATALYST FOR THE ALKYLATION OF ISOBUTANE WITH 2-BUTENE. Presented at 2002 Annual AIChE, Green Reaction Engineering I, Indianapolis, IN, November 03 - 08, 2002.
Impact/Purpose:
To inform the public.
Description:
Ionic liquids as a clean catalyst for the alkylation of isobutane with 2-butene
Kyesang Yoo, a Vasudevan V. Namboodiri,b Panagiotis G. Smirniotis,*a and Rajender S. Varma*b
a Department of Chemical Engineering, University of Cincinnati, Cincinnati, OH 45221-0171, USA.
E-mail: panagiotis.smirniotis@uc.edu
b Clean Processes Branch, National Risk Management Research Laboratory, US Environmental Protection Agency, Cincinnati, OH 45268, USA. E-mail: Varma.Rajender@epa.gov
Abstract:
Alkylation of isobutane with butenes has traditionally employed either hydrofluoric acid or sulfuric acid as catalyst. Both these processes share inherent environmental and safety concerns associated with acid spillage and waste disposal. The present study evaluates the use of 1-alkyl,3-methylimidazolium halide-AlCl3 ionic liquids as clean catalysts for the alkylation of isobutane with 2-butene. These ionic liquids mainly consist of tetrahaloaluminates as anions and are highly acidic (Hammett acidities up to -18) that provide best activity. Among various ionic liquids examined, the one bearing relatively longer alkyl side chain (Octyl) showed highest activity, presumably due to the enhanced solubility of substrates in the catalyst media. The ratio of alkylation products trimethylpentane (TMP) to dimethylhexane (DMP), over 1-octyl,3-methylimidazolium bromide-AlCl3 ionic liquid is found to be 0.3 which is comparable to the selectivity obtained with commercial sulfuric acid catalyst (0.5) under identical experimental conditions. The studies on the catalytic properties of these unique liquids via variation of anions will be presented.