(87e) Cycloaddition of Isoamylene and α-Methylstyrene in a Microreactor Using Filtrol-24 Catalyst

Aqueous sulfuric acid is conventionally used as the catalyst for the cycloaddition reaction between isoamylene and α-methylstyrene to yield indane compounds 1,1,2,3,3,-pentamethylindane and 3-ethyl-1,1,3-trimethylindane, which are intermediate cyclic products used in the synthesis of musk fragrances. This exothermic reaction is conventionally carried out industrially in large semi-batch reactors. Solid catalysts offer various advantages over the corrosive aqueous sulfuric acid catalyst including the elimination of, expensive separation and purification steps, and the need to use corrosion resistant materials of construction. A microreactor, which has enhanced heat and mass transfer characteristics, was used for the reaction using an acidic solid catalyst, Filtrol-24. A parametric study to obtain the dependence of product yield, reactant conversion and space-time yield on catalyst particle size, residence time, velocity, temperature, pressure and the molar ratio of the reactants in the feed was conducted. Through this study the optimum reaction conditions were obtained. The cycloaddition reaction was also performed in the semi-batch reactor using Filtrol-24 catalyst in order to compare its performance with that of the microreactor. Similar product yields were obtained in both the microreactor and the semi-batch reactor, but the space-time yield in the microreactor was four times larger than that obtained in the semi-batch reactor at optimum reaction conditions in both reactors.