摘要
以甘油和CO_2为原料合成甘油碳酸酯,不仅为CO_2资源化利用提供了一种新途径,并实现了生物柴油副产物废甘油的高值化利用,将CO_2和废甘油同时转化为高附加值的化学品具有重要的研究意义和应用价值~([1])。CO_2和甘油合成甘油碳酸酯的平衡常数很小,说明该反应在热力学上是不利的,因此合适的催化剂和脱水剂可以提高甘油碳酸酯的收率。本工作中我们比较了不同脱水剂对甘油碳酸酯收率的影响,发现2-氰基吡啶是最有效的脱水剂。通过对不同催化剂、脱水剂的筛选,发现在无催化剂的条件下,以2-氰基吡啶为脱水剂,甘油碳酸酯的收率可以达到16.8%。研究表明,甘油与2-氰基吡啶的摩尔比为1:3时,甘油碳酸酯产率最高。同时,甘油碳酸酯产率与CO_2压力成正比关系。由于2-氰基吡啶具有较强的碱性,可以吸附活化二氧化碳,水解产物吡啶甲酰胺分子内存在氢键~([2]),可以吸附活化甘油,因此2-氰基吡啶在二氧化碳与甘油反应中既是催化剂又是脱水剂,促进甘油碳酸酯的生成。
The synthesis of glycerol carbonate(GC) from glycerol and carbon dioxide not only provided a new approach to utilize greenhouse gas carbon dioxide,but also solved the utilization of glycerol to prepare high-valued chemicals,which is of significance in fundamental research and applications~([1]).However,the reaction cannot occur spontaneously in the standard conditions,as it is limited by thermodynamics.Hence,proper catalysts and dehydrating agent can promote the yield of GC.In this work,the results of several dehydrating agents indicated that 2-cyanopyridine was the most effective dehydrating agent.Through the screening of different oxide catalyst and dehydrating agent,surprisingly,2-cyanopyridine can promote GC yield,and it reached 16.8%in the absence of catalysts.It illustrated that when the mole ratio of glycerol and 2-cyanopyridine was 1:3,GC reached the highest yield,and the yield of GC was proportional to the CO_2 pressure.As 2-cyanopyridine has strong alkaline,which can adsorption carbon dioxide,and hydrolyzate has hydrogen bond~([2]),which can adsorption glycerol.Therefore,2-cyanopyridine acted as catalyst and dehydrating agent during the reaction,promoting the formation of GC.
引文
[1]Jun Ma;Jinliang Song;Buxing Han,Green Chem.,2012,14:1743-1748
[2]M.Honda;M.Tamura;Y.Nakagawa;K.Nakao;K.Suzuki;K.Tomishige,J.Catal.,2014,318:95–107.
