固体酸催化烯烃改性生物油酚类化合物研究

选取生物油中含量较高的愈创木酚、儿茶酚和苯酚为酚类模型化合物,以蒙脱土K-10负载的Cs2.5H0.5PW12O40为固体超强酸催化剂,苯酚/1-辛烯烷基化反应为探针,考察了催化剂负载量,反应温度及物料摩尔比等因素对酚类烷基化反应的影响.结果表明,在60～100℃范围内,30%Cs2.5H0.5PW12O40/K-10对苯酚烷基化反应具有很好的催化活性和选择性,原料摩尔比为1时苯酚氧烷基化产物的选择性最好.愈创木酚中甲氧基的位阻效应使其转化率在相同条件下比苯酚低很多,相应氧烷基化产物的选择性也很低.儿茶酚与1-辛烯反应主要生成单羟基氧烷基化产物,100℃时选择性仍高达96%.升高温度有利于烷基化改性反应的进行,但产物中氧烷基化产物的选择性随着温度升高而降低.

Phenolic Model Reactions with Olefin for Bio-oil Upgrading over Solid Acid Catalyst

Model liquid phase reactions of 1-octene with phenol, catechol and guaiacol, respectively, were carried out over acid catalyst 30%Cs2.5H0.5PW12O40/K-10 for bio-oil upgrading. 1-Octene alkylation of phenol was selected to determine the catalyst loading, upgrading temperature and molar ratio of feedstock. The catalyst was very active and extremely selective for phenol alkylation at 60—100 ℃. The selectivity for O-alkylated phenol was highest when the phenol/1-octene mole ratio is 1∶1. Steric hindrance by methoxy group on the ortho-position relative to the —OH in guaiacol can dramatically reduce conversion and O-alkylation selectivity. The main product of catechol alkylation with 1-octene in the experimental conditions was mono-O-alkylation product, the selectivity was as high as 96% even at 100 ℃. All phenolic compound conversions increased substantially with increasing temperature, however, O-alkylation selectivity dropped progressively as temperature increased.