Kinetic modelling of the liquid-phase dimerization of isoamylenes on Amberlyst 35

Selectivity, conversion, yield and kinetics of the liquid-phase dimerization of 2-methyl-1-butene and 2-methyl-2-butene mixture have been studied in a batch stirred tank reactor in the temperature range 60-100 °C catalysed by the acid resin Amberlyst 35 and using ethanol as a selectivity enhancer. Selectivity to dimers showed a maximum at RIA/EtOH = 20. Obtained diisoamylenes consisted mainly of 3,4,4,5-tetramethyl-2-hexene, 2,3,4,4-tetramethyl-1-hexene and 3,4,5,5-tetramethyl-2-hexene. LHHW type kinetic model was derived for the dimerization reaction as a whole. The kinetic model assumes that three active sites take part in the rate-limiting step of dimerization; the apparent activation energy for the dimerization reaction being 65 kJ mol−1. A pseudohomogeneous kinetic model was used to describe the dimerization reaction network. The apparent activation energy for each dimerization reaction was found to be in the range 61-81 kJ mol−1.