Etherification of dimethylbutenes in excess methanol

Oxygenated compounds such as ethers produced by the reaction of alcohols and alkenes have good potential for use as performance and environmental enhancing additives for transportation fuels. In this study, the production of the C7 ether, 2,3-dimethyl-2-methoxybutane (DM2MB), was investigated in a batch reactor from 323–343 K at high methanol concentrations. A macroporous cation exchange resin, Amberlyst 15, was employed as catalyst for the etherification of 2,3-dimethyl-1-butene (DM1B) and 2,3-dimethyl-2-butene (DM2B) with methanol. Kinetic rate constants were correlated by fitting the experimental data to kinetic equations based on a pseudo-homogeneous model. Experimental results were obtained for the effects of temperature on simultaneous etherification and isomerization of DM1B and DM2B and differences in the reactivities of the two alkenes were noted. Kinetic and equilibrium parameters obtained from the Arrhenius and Vanʹt Hoff equations agreed well with values obtained from similar studies in the literature.