微波促进活性炭负载磷钨酸催化合成长链季戊四醇缩醛

以活性炭负载磷钨酸为催化剂,利用微波辐射法合成了十种长链季戊四醇单、双缩醛,其中季戊四醇双缩辛醛属新化合物.以n-十二醛与季戊四醇的缩合为模型反应进行优化,其优化反应条件为:①单缩醛:溶剂DMF,催化剂用量1.0 g,季戊四醇30 mmol,n-十二醛30 mmol,微波功率300 W,辐射时间8 min,产率74.5%;②双缩醛:溶剂苯,催化剂用量0.6 g,季戊四醇30 mmol,n-十二醛66 mmol,微波功率450 W,辐射时间3 min,产率为85.2%.产物经过元素分析I、R和1H NMR表征.

Synthesis of Long-chain Pentaerythritol Acetals Catalyzed by Phosphotungstic Acid Supported on Active Carbon under Microwave Irradiation

Ten kinds of long-chain pentaerythritol mono-acetals and diacetals were synthesized through the condensation reaction of pentaerythritol with long-chain aldehydes catalyzed by phosphotungstic acid supported on active carbon under microwave irradiation,and were characterized by IR,()~1HNRM and element analysis.Under the optimum reaction conditions(mono-acetal:solvent DMF,catalyst amount 1.0()g,pentaerythritol 30()mmol,n-dodecanal 30()mmol,microwave power 300()W,irradiation time 8()min;diacetal: solvent benzene,catalyst amount 0.6()g,pentaerythritol 30()mmol,n-dodecanal 66()mmol,microwave power 450()W,irradiation time 3()min),the yields of mono-acetal and diacetal were 74.5% and 85.2% respectively.Among these products,diacetal of pentaerythritol with n-octanal is a new compound.