Continuous-flow synthesis of pentaerythritol:Alkalinity release of sodium solvation cage to control aldol and Cannizzaro reactions  

作　　者：Zhengguang Wang Xin Qu Xingke Yuan Zhanpeng Gao Niu Hu Jiansheng Wei Wenpeng Li Zhirong Yang Jingtao Wang 

机构地区：[1]School of Chemical Engineering,Zhengzhou University,Zhengzhou 450001,China [2]Puyang Research Society of Chemical Technology Industry,Puyang 457000,China

出　　处：《Chinese Journal of Chemical Engineering》2025年第3期23-29,共7页中国化学工程学报(英文版)

基　　金：funded by the National Natural Science Foundation of China(22478632);Key Scientific and Technological Project of Henan Province(242102321032).

摘　　要：Continuous-flow upgrading of pentaerythritol synthesis technology via base-catalyzed aldol and Cannizzaro reactions of formaldehyde and acetaldehyde faces the challenge of effectively controlling the critical side reaction of hydroxymethyl acetaldehyde(HA)to the acrolein intermediate.Here,we first identified the forms of industrial formaldehyde as methane diol that easily converts to the alkaline formaldehyde under alkaline(NaOH)environment.The carbonyl group of alkaline formaldehyde induces deprotonation of acetaldehyde instead of the recognized base-hydroxyl group-induced deprotonation,and it needs to overcome only 18.31 kcal·mol^(-1)(1 kcal=4.186 kJ)energy barrier to form key intermediates of HA.The sodium solvation cage formed by NaOH hexa-coordinated formaldehyde effectively inhibits the alkalinity,thus contributing to a high energy barrier(46.21 kcal·mol^(-1))to unwanted acrolein formation.In addition,the solvation cage gradually opens to increase the alkalinity with the consumption of formaldehyde,thus facilitating the subsequent Cannizzaro reaction(to overcome 11.77 kcal·mol^(-1)).In comparison,strong alkalinity promotes the formation of acrolein(36.65 kcal·mol^(-1))to initiate the acetal side reaction,while weak alkalinity reduces the possibility of the Cannizzaro reaction(to overcome 20.44 kcal·mol^(-1)).This theoretically reveals the importance of the segmented feeding of weak and strong bases to successively control the aldol reaction and Cannizzaro reaction,and the combination of Na_(2)CO_(3) or HCOONa with NaOH improves the pentaerythritol yield by 7%to 13%compared to that of NaOH alone(70%yield)within 1 min at a throughput of 155.7 ml·min^(-1).

关 键 词：Alkaline formaldehyde Sodium solvation cage Aldol reaction Cannizzaro reaction CONTINUOUS-FLOW PENTAERYTHRITOL 

分 类 号：O62[理学—有机化学]