碳酸二甲酯对淀粉的甲基化反应

Methylation Reaction of Starch with Dimethyl Carbonate

以碳酸二甲酯(DMC)为甲基化试剂与淀粉(St)进行了常压甲基化反应,实验确定了甲基化反应过程的主要影响因素。结果表明,以碳酸钾/水为淀粉的活化试剂,溴化十六烷基三甲铵(CTAB)为催化剂,按m(St)∶m(DMC)∶m(H2O)∶m(K2CO3)∶m(CTAB)=70∶90∶90∶10∶0.5,于78℃反应9h,淀粉甲基化产物的甲氧基质量分数w(—OCH3)=4.1%。

Dimethyl carbornate（DMC）was used as a methylating reagent to react with starch to prepare methyl starch,and the methylating process was investigated to find out the relationship between reaction condition and methyoxyl content [w（—OCH3）%,mass percent] of methyl starch.The result shows that the methoxyl content of methyl starch reaches 4.1%,with potassium carbonate for the starch activation reagent and cetyltrimethylammonium bromide（CTAB）for the methyl reacting catalyst,with a condition of mass ratio of m（Starch）∶m（DMC）∶m（K2CO3）∶m（H2O）∶m（CTAB）=70∶90∶10∶90∶0.5,for 9 h,at 78 ℃ under the atmospheric pressure.