磷钨酸铯催化合成对甲氧基苯乙酮

Synthesis of p-Methoxyacetophenone Catalyzed by Cesium Phosphotungstate

以磷钨酸铯(Cs2.5H0.5PW12O40)为催化剂合成了对甲氧基苯乙酮(p-MOAP),采用傅里叶变换红外光谱、X射线衍射、N2吸附和NH3程序升温脱附等方法对Cs2.5H0.5PW12O40催化剂进行了表征;考察了Cs2.5H0.5PW12O40催化剂活化温度、反应条件及反应产物等对苯甲醚乙酰化反应的影响。表征结果显示,多孔性的Cs2.5H0.5PW12O40催化剂保持了H3PW12O40的Keggin结构和酸强度,但酸量明显小于H3PW12O40。实验结果表明,适宜的p-MOAP合成条件为:300℃下活化的Cs2.5H0.5PW12O40催化剂用量为0.18g(以20mmol乙酸酐计)、n(苯甲醚):n(乙酸酐)=10、反应温度115℃、反应时间40min。在此条件下进行了4次重复实验,p-MOAP的收率达61.3%～64.8%、选择性达96.10%～96.80%。苯甲醚乙酰化反应的产物p-MOAP和醋酸对Cs2.5H0.5PW12O40催化剂的活性具有抑制作用。

p-Methoxyacetophenone （ p-MOAP ） was synthesized from anisole （ AN ） and acetic anhydride （ AA ） over cesium phosphotungstate （ Cs2.5 H0.5 PW12O40 ） catalyst. The catalysts were characterized by means of FTIR, XRD, N2 adsorption and NH3-TPD. Effects of Cs2.5H0.5PW12O40 catalyst activation temperature and reaction conditions on yield and selectivity to p-MOAP were investigated. The porous Cs2.5H0.5PW12O40 catalyst keeps original Keggin structure and acid strength of H3PW12O40, but acid amount of Cs25 H05 PW12O40 is less than that of H3PW12 O40. Under optimum reaction conditions： Cs2.5H0.5PW12O40 catalyst activated at 300°C, the catalyst dosage 0.18 g（based on 20 mmol AN）, mole ratio of AN to AA 10, reaction temperature 115 °C and reaction time 40 min, yield and selectivity to p-MOAP are 61.3% -64.8% and 96.10% -96.80%, respectively. The experiments confirm that products of AN acetylation including p-MOAP and acetic acid inhibit catalytic activity of Cs2.5 H0.5PW12O40 catalyst.