Abstract
Catalytic isomerization of n-hexane to its corresponding branched liquid hydrocarbon isomers by three different ionic liquids (ILs) having general formula; [BmimCl·2AlCl3], [BPyCl·2AlCl3] and [Et3NHCl·2AlCl3] were investigated in the present work. Due to the optimum acidic nature of the ILs, the reaction moves through faint conditions in a liquid-liquid biphasic reaction mode, this confirms a minimum extent of unwanted cracking side-reactions. ILs showed good catalytic activity due to their appreciable Brönsted and Lewis acidity. The BmimCl·2AlCl3 and Et3NHCl·2AlCl3 show higher conversion of n-hexane compared to BPyCl·2AlCl3 under similar reaction condition. The selectivity of isomers is lower at higher conversion range. On increasing the reaction time and temperature, the conversion of n-hexane rises up, while the selectivity of i-alkanes and i-hexanes were reduced. The optimal reaction temperature, reaction time and IL/n-hexane ratio were 30 °C, 24 hand 1:1, respectively; the conversion of n-hexane is 25.7%, 11.52%, 36.3%, the selectivity to i-alkanes is 97.58%, 99.55%, 99.16%, and selectivity to i-hexane 87.28%, 70.10%, 95.86%, respectively.
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•[BmimCl·2AlCl3], [BPyCl·2AlCl3] and [Et3NHCl·2AlCl3] have been synthesized.•Effective isomerization of n-hexane has been catalyzed by synthesized ILs.•The ILs exhibited appreciable catalytic activity due to Brönsted and Lewis acidity.•BmimCl·2AlCl3 and Et3NHCl·2AlCl3 showed good catalytic activity than BPyCl·2AlCl3.•Optimal reaction condition is 30 °C, 24 h and 1:1.