Synthesis of 3-methy-3-buten-1-ol catalyzed by immobilized ZnCl₂

Immobilized ZnCl₂ (Silzic) catalyst was prepared and used in the synthesis of 3-methyl-3-buten-1-ol (MBOH) from isobutylene and formaldehyde; the effects of the reaction parameters, such as temperature, molar ratio of isobutene to formaldehyde, reaction time and catalyst content on the reaction behavior were investigated. The results showed that the conversion of formaldehyde is over 99% under various conditions. The reaction temperature as well as the catalyst acidity and the amount of the acid sites are dominant factors in influencing the selectivity to MBOH. Under the optimum reaction conditions, i.e. 210 ℃, 8 g 1,4-dioxane, 1.5 g polyoxymethylene, n(isobutylene)/n(polyoxymethylene) ratio of 7, 30 mg Silzic (1 mmol/g), and reaction time of 2 h, the selectivity and yield of MBOH reach 93.8% and 93.4%, respectively. The Silzic catalyst exhibits certain reusability; the yield of MBOH remains 85.2% after reusing the catalyst for 5 times.