磷钨酸催化合成对甲氧基苯乙酮

以苯甲醚和乙酸酐为原料,在磷钨酸催化作用下,通过Friedel-Crafts酰基化反应合成了对甲氧基苯乙酮;考察了催化剂预处理温度、原料配比、催化剂用量、反应温度、反应时间、催化剂种类对产物收率的影响;考察了传统磁力搅拌加热、微波辐射、超声波辐射3种加热方式对酰基化反应的影响。实验结果表明,不同的杂多酸中磷钨酸的催化活性最好;在磷钨酸预处理温度150℃、苯甲醚0.1mol、n(乙酸酐)∶n(苯甲醚)=1.5、磷钨酸用量1.0g、反应时间4h、磁力搅拌加热、反应温度100℃的条件下,对甲氧基苯乙酮的收率为52.9%;以微波辐射方式合成的效果最好,其次是超声波辐射,两者都优于传统的磁力搅拌加热方式;磷钨酸催化剂可再生重复使用,再生焙烧温度越高,回收后的磷钨酸催化效果越好。

Synthesis of p -Methoxyacetophenone with Phosphotungstic Acid Catalyst

p-Methoxyacetophenone was synthesized by Friedel-Crafts acylation of anisole with acetic anhydride using phosphotungstic acid as catalyst. Effects of pretreatment temperature of the catalyst, mole ratio of anisole to acetic anhydride, catalyst dosage, reaction temperature and time on p-methoxyacetophenone yield were investigated. Under optimal conditions: pretreatment temperature of the catalyst 150 ℃, n(acetic anhydride) ∶n(anisole) 1.5, anisole dosage 0.1 mol, catalyst dosage 1.0 g, magnetic stirring, electrical heating, reaction temperature 100 ℃ and reaction time 4 h, p-methoxyacetophenone yield is 52.9%. Catalytic activities of different heteropolyacids in acylation were studied under above conditions. Catalytic activity of phosphotungstic acid is the best among silicotungstic acid, molybdophosphoric acid and phosphotungstic acid. Comparing with the other ordinary electric heating modes, the effect of microwave irradiation is better and the next is ultrasonic irradiation. The phosphotungstic acid catalyst can be reused. Catalytic activity of the reused phosphotungstic acid rises along with lifting of regeneration calcination temperature.