An Efficient and Green Approach for the Esterification of Aromatic Acids with Various Alcohols over H<sub>3</sub>PO<sub>4</sub>/TiO<sub>2</sub>-ZrO<sub>2</sub>
作者:Roozbeh Javad Kalbasi、Ahmad Reza Massah、Zeynab Barkhordari
DOI:10.5012/bkcs.2010.31.8.2361
日期:2010.8.20
$TiO_2-ZrO_2$ was prepared with surfactant through a sol-gel method. Catalysts containing 5 - 35% $H_3PO_4$ were prepared using these oxides. Subsequently the catalytic performance of prepared catalysts was determined for liquid phase esterification of aromatic acids. $H_3PO_4/TiO_2-ZrO_2$ has been used as catalyst to synthesize various novel esters by esterification of some aromatic acids with aliphatic alcohols (2-propanol, 1-butanol, iso butanol, 3-pentanol, 1-hexanol, heptanol, cyclo heptanol, octanol and decanol). Under optimized conditions, maximum yields and selectivity (100%) to the corresponding ester, was obtained by using 25 wt % $H_3PO_4/TiO_2-ZrO_2$ as catalyst. The Catalyst can be easily recycled after reaction and can be reused without any significant loss of activity/selectivity performance. No by-product formation, high yields, short reaction times, mild reaction conditions, operational simplicity with reusability of the catalyst are the salient features of the present synthetic protocol. The reaction was carried out under solvent-free condition.
$TiO_2-ZrO_2$ 是通过溶胶-凝胶法与表面活性剂一起制备的。利用这些氧化物制备了含 5 - 35% $H_3PO_4$ 的催化剂。随后测定了所制备催化剂在芳香酸液相酯化过程中的催化性能。$H_3PO_4/TiO_2-ZrO_2$ 被用作催化剂,通过一些芳香酸与脂肪醇(2-丙醇、1-丁醇、异丁醇、3-戊醇、1-己醇、庚醇、环庚醇、辛醇和癸醇)的酯化反应合成各种新型酯。在优化条件下,使用 25 wt % $H_3PO_4/TiO_2-ZrO_2$ 作为催化剂可获得相应酯类的最高产率和选择性(100%)。催化剂在反应后很容易回收,并且可以重复使用,活性/选择性性能不会有任何明显的损失。无副产物生成、产率高、反应时间短、反应条件温和、催化剂可重复使用且操作简单是本合成方案的显著特点。反应在无溶剂条件下进行。