Zn(OAc)2·2H2O热处理对2,4-甲苯二氨基甲酸甲酯合成的影响

Effect of thermal treatment of Zn(OAc)2·2H2O on synthesis of 2,4-toluene dicarbamate

摘要:

借助TG、FTIR和XRD表征分析了Zn(OAc)2·2H2O在热处理过程中组成的变化。Zn(OAc)2·2H2O在100 ℃热处理8 h内仅发生脱水过程；在120 ℃热处理4 h，产物中有Zn4O(OAc)6生成，并且其含量随热处理时间的延长而增加；在160 ℃热处理6 h时有ZnO生成，延长至12 h后产物大部分为ZnO。将Zn(OAc)2·2H2O在不同热处理条件下得到的产物用于催化合成2,4-甲苯二氨基甲酸甲酯（2,4-TDC），当反应温度为160 ℃时，Zn(OAc)2·2H2O在100 ℃热处理8 h后催化合成2,4-TDC的收率达到88.1%，说明该反应温度下Zn(OAc)2的催化活性较高；当反应温度为180 ℃时，Zn(OAc)2·2H2O在140 ℃热处理8 h后催化合成2,4-TDC的收率达到92.8%，说明该反应温度下Zn4O(OAc)6拥有更高的催化活性。

Abstract:

The change of composition during the thermal treatment of Zn(OAc)2·2H2O was analyzed by TG, FTIR and XRD characterization. At the thermal treatment temperature of 100 ℃ within 8 h, only dehydration process of Zn(OAc)2·2H2O occurred. After the thermal treatment at 120 ℃ for 4 h, Zn4O(OAc)6 was formed and its amount increased as the time of thermal treatment extended. ZnO was formed after the thermal treatment at 160 ℃ for 6 h, and most of the products were ZnO after 12 h. The products of Zn(OAc)2·2H2O under different thermal treatment conditions were used for the synthesis of 2,4-toluene dicarbamate (2,4-TDC).At the reaction temperature of 160 ℃, the yield of 2,4-TDC catalyzed by Zn(OAc)2·2H2O under the heat treatment at 100 ℃ for 8 h reached 88.1%, indicating that the catalytic activity of Zn(OAc)2 was higher at 160 ℃. When the reaction temperature reached 180 ℃, the yield of 2,4-TDC catalyzed by Zn(OAc)2·2H2O under the heat treatment at 140 ℃ for 8 h was 92.8%, showing that Zn4O(OAc)6 had a higher catalytic activity at 180 ℃.