Na_2WO_4-H_2O_2体系催化1,2-丙二醇和丁二醇的选择氧化

以钨酸钠为催化剂、30％H2O2为氧化剂,选择性氧化1,2-丙二醇、1,2-丁二醇、1,3-丁二醇。研究了酸性助剂的作用,比较了钨酸钠、钼酸钠、磷钨酸和磷钼酸的催化性能以及不同底物在体系中的反应结果。反应时间的延长和温度的升高虽然可以提高转化率,但对选择性生成羟基酮不利。催化剂和氧化剂的增加则促进副产物乙酸和甲酸的生成。增加酸性助剂可以提高1,2-丙二醇的转化率,但反应生成羟基丙酮的选择性降低。以钨酸钠为催化剂,在反应条件为温度55℃,时间60 mm,n(Na2WO4·2H2O)／n(邻苯二酚)=1时,1,2-丙二醇转化率可达13％左右,生成的羟基丙酮的选择性可达92.3％。该反应条件下,1,2-丁二醇、1,3-丁二醇的转化率分别为29.2％和77.5％,生成的1-羟基-2-丁酮和4-羟基-2-丁酮的选择性分别为65.8％和85.3％。

Selective Oxidation of 1,2-Propanediol and Butanediol Catalyzed by Na2WO4-H2O2

Catalytic oxidation of 1,2-propanediol and butanediol using Na2WO4·2HO as catalyst and hydrogen peroxide (30 %) as oxidant was studied. Effect of acidic auxiliary additive on oxidation of 1,2-propanediol and butanediol, and catalytic performance of sodium tungsten, sodium molybdate and heteropoly acid were compared. Conversions of substrate increased along with reaction time or reaction temperature, but selectivity of forming hydroxyketone decreased. Increase of quantity of catalyst or oxidant would head to formation of more by - products acetic acid and formic acid. Increase of acidity of auxiliary additive would be favorable for conversion of 1,2-propanediol but selectivity of forming hydroxyacetone decreased. When Na2WO4 was used as catalyst, under the optimum reaction conditions: temperature 55℃, time 60 min, n (Na2WO4·2H2O)/n (o-hydroxyl phenol)=1,conversion of 1,2- propanediol was 13% and selectivity of hydroxyacetone could up to 92.3% .Under similar conditions, conversions of 1,2-butanediol and 1,3- butanediol were 29.2% and 77.5% , selectivity of forming 1-hydroxy-2- butanone and 4-hydroxy-2-butanone were 65.8% and 85.3 % , respectively.