NKC-9型树脂催化合成单新戊二醇缩1,4-环己二酮

Synthesis of 1,4-Cyclohexanedione Mono-neopentylketal over NKC-9 Macroporous Resin

以阳离子交换树脂为固体酸催化剂,新戊二醇与1,4-环己二酮在二氯甲烷溶剂中脱水缩合合成了单新戊二醇缩1,4-环己二酮(单缩酮)。实验考察了不同类型阳离子交换树脂的催化效果,结果表明,NKC-9型树脂具有良好的催化作用。通过单因素分析及正交试验,获得了该催化剂催化合成单新戊二醇缩1,4-环己二酮的最佳条件:在二氯甲烷溶液中,于25℃和反应液浓度为1.3mol·L-1,催化剂用量为反应物总质量的15.4%,反应110min,新戊二醇的转化率达94%,所得目标产物单缩酮收率达74.8%,气相色谱测定其纯度为96%。通过红外光谱分析、核磁共振谱图分析验证了所合成的产物为目标产物单缩酮。与传统酸性催化剂相比,采用树脂NKC-9作为反应催化剂不仅提高了反应收率,简化了反应工艺流程,无酸腐蚀和污染问题,且催化剂无需处理可重复使用多次。

Starting from 1,4-cyclohexane-dione and neopentyl glycol, the 3,3-dimethyl-l,5-dioxa-spiro[5.5] undecan-9-one （monoketal） was synthesized by using ion-exchange resins as catalyst. Several different ion-exchange resins were selected, and it was found that the catalyst ofNKC-9 macroporous resin is better than the others. Using it, the optimum synthesis conditions were determined by mono-factor analyses and orthogonal tests, and the product was characterized by IR and ^1H-NMR. The results show that, under the conditions determined above （i.e. the reaction temperature of 25℃, reactant concentration of 1.3 mol·L^-1 in dissolvent of dichloromethane, the used catalyst weight equal to 15.4% of the feedstock, reaction time of 110 min and under stirring）, the conversation of neopentyl glycol is 94%; the yield and the purity of the monoketal can reach 74.8 and 96% （determined by GC）, respectively. Compared with using sulfuric acid as catalyst, the present procedure is a green productive technology characterized by process simplification, higher yield and no corrosion for facilities. Moreover, the NKC-9 macroporous resin can be used for many times.