非光气法制备1,6-己二氨基甲酸丁酯

Synthesis of Dibutyl Hexamethylenedicarbamate Without Phosgene

用氨基甲酸丁(BC)代替光气作为羰基化试剂,以1,6-己二胺(HDA)为原料、正丁醇为溶剂,在催化剂作用下一步法合成了1,6-己二异氰酸酯的前体1,6-己二氨基甲酸丁酯(BHDC)。考察了催化剂种类和反应条件对 BHDC 合成反应的影响,并指出了反应体系中可能存在的副反应及副产物。实验结果表明,在以硝酸钇为催化剂、催化剂用量为 HDA 质量的5%、n(正丁醇):n(BC):n(HDA)=15:4:1、反应温度180℃的条件下反应5 h,HDA 的转化率接近100%,BHDC 的收率达到85%。用 X射线衍射和 X 射线光电子能谱对硝酸钇催化剂进行了表征,结果显示硝酸钇的晶形、组成、元素化学状态在反应过程中发生了改变,但这些改变没有导致催化剂的活性明显降低。

Dibutyl hexamethylenedicarbamate （BHDC） is a precursor of diisocyanatohexane. Through a one-step process BHDC can be synthesized from 1,6-hexamathylenediamine （HDA） by using butyl carbamate （BC） as the carbonylating reagent to displace the dangerous phosgene, hydrate of yittrium nitrate as catalyst and n-butanol as solvent. Activities of different catalysts, different reaction conditions, possible side reactions and byproducts were investigated. When the reaction was carded out at 180 ℃ for 5 h using Y （ NO3 ） 3· 6H2O as catalyst （ catalyst mass fraction 5 % based on HDA）, and n （ n-butanol ） ： n （ BC ） ： n（HDA） = 15 ： 4 ： 1, HDA conversion is nearly 100% and yield to BHDC is 85%. Fresh and used yttrium nitrate catalysts were characterized by means of XRD and XPS. Although transformation of crystalline to amorphous state, loss of crystalline water and existence of yttrium oxide were found in used catalyst, no obvious deactivation is observed after the catalyst was reused for four times.