Investigation into 1,3-butadiene and other bulk chemicals' formation from bioethanol over Mg–Al catalysts

Abstract

Mg–Al catalysts were adopted in the direct synthesis of 1,3-butadiene and other bulk chemicals from bioethanol. The influence of MgO content and sample calcination temperature on the catalytic performance was investigated. The optimization of reaction conditions for 1,3-butadiene, ethylene and 1-butanol, including reaction temperatures and the feed rate of ethanol, was also carried out. The catalysts were characterized by X-ray diffraction, nitrogen sorption, SEM, NH₃-TPD, CO₂-TPD and FTIR of adsorbed pyridine. On the basis of these analysis results and catalytic performance of yielding 1,3-butadiene, both the MgO content and the calcination temperature play a great role on the nature of acid and basic sites, then the proper active sites for producing 1,3-butadiene and other important chemicals such as ethylene and 1-butanol have been elaborated. The balance of moderate acid–basic sites is crucial to production of 1,3-butadiene from ethanol. Ethylene is obtained on strong acid and strong basic sites. 1-Butanol tends to form on the strong basic sites. To further improve the target product selectivity, modifiers adjusting the balance of acidity–basicity need to be involved in the Mg–Al catalysts.