科研之友
微信
新浪微博
Facebook
分享链接
摘要
The impact of acid/base properties (determined by adsorption microcalorimetry) of various catalysts on the cross-aldolization of acetaldehyde and formaldehyde leading to acrolein was methodically studied in oxidizing conditions starting from a mixture of methanol and ethanol. The aldol condensation and further dehydration to acrolein were carried out on catalysts presenting various acid/base properties (MgO, Mg-Al oxides, Mg/SiO2, NbP, and heteropolyanions on silica, HPA/SiO2). Thermodynamic calculations revealed that cross-aldolization is always favored compared with self-aldolization of acetaldehyde, which leads to crotonaldehyde formation. The presence of strong basic sites is shown to be necessary, but a too high amount drastically increases COx production. On strong acid sites, production of acrolein and carbon oxides (COx) does not increase with temperature. The optimal catalyst for this process should be amphoteric with a balanced acid/base cooperation of medium strength sites and a small amount (<100molg(-1)) of very strong basic sites (Q(diff)>150kJmol(-1)).
- 出版日期2017-9-11
