Kinetics study of 3-methylthiophene alkylation with isobutylene catalyzed by NKC-9 ion exchange resin

A series of experiments were carried out in a stirred batch reactor at the temperature range of 333-363 K and the pressure of 1.5-2.5 MPa by using NKC-9 ion-exchange resin to investigate the alkylation kinetics of 3-methylthiophene (3MT) with isobutylene (IB). The effect of various operation parameters such as stirring speed, catalyst particle size, temperature, pressure, and sulfur content on the conversion and selectivity of alkylation reaction were studied. Experimental results indicated that the alkylation of 3MT with IB was followed by a parallel reaction of IB oligomerization; higher temperature could improve the alkylation activity while lower temperature was profitable to the reaction selectivity over the NKC-9 catalyst; however, the operating pressure has little effect on the alkylation and oligomerization; much sulfur content could inhibit IB dimerization. The Eley-Rideal (ER) law can be used to explain the reaction mechanism, and the kinetics models that considered the alkylation and oligomerization at the same time were established. Kinetics parameters were solved, and the calculation results agreed well with the experimental results.