负载型钴催化剂促进的不饱和脂肪酸酯中的双键过氧化

Abstract

考察了负载型催化剂CO/Al2O3的不饱和脂肪酸酯中双键的过氧化反应性能,结合物相组成和形貌特征分析发现,低负载量时催化剂表面形成的界面型CO3O4活性物种,过氧化活性较高,而负载量增加则造成游离态CO2O3物种对原活性位的覆盖,过氧化活性在钴负载量为3%(质量分数)时达到最高.通过比较负载型钴催化剂的H2-TPr结果,揭示出界面型CO3O4物种在催化循环中具有活化分子氧的优势,加速了过氧化反应的速控步骤.经对过氧化反应的温度、时间、空气流速以及原料酯交换程度等工艺参数优化后,获得了过氧化值(POV)为546 MMOl/kg的过氧化效率,这将有助于合成亚硫酸化程度较高的皮革加脂剂.

Supported Co/Al2O3 catalysts were prepared by wet impregnation method and evaluated in peroxidation of unsaturated fatty acid ester by air.Phasic and morphological analysis revealed that an epitaxial Co3O4 species emerged when cobalt component started to deposit on alumina support.The catalytic peroxidation activity rapidly elevated along with the cobalt loading as far as 3%(by mass),while further deposition of cobalt component blocked the active sites of Co3O4.Compared to Co2O3 in free state,the epitaxial Co3O4 species possesses the relative superiority in activation of molecular oxygen as evidenced by H2-TPR,thus the rate determinative step of peroxidation is prominently accelerated.By optimization of the operating parameters,a peroxidation level of POV=546 mmol/kg was obtained.Based on this peroxidation product,a kind of fur fatliquor with extensive sulfitation could be subsequently gained.