Heteroatom Michael-addition Reaction Of Acrylic Acid Derivatives

Poly(ester amide)s is a kind of hetero-chain polymer containing both ester and amide groups.Due to its biodegradability and excellent mechanical properties,it has widely applications in biomedicine,coatings,fibers and other fields.The improvement and optimization of poly(ester amide)s synthesis methods has always been a hot topic.Therefore,it is very important to explore an economical and environmentally friendly synthetic route with lower synthesis cost and less synthesis steps.The preparation of small molecule esters and amides is easy to control relative to the preparation of macromolecule esters and amides.Connecting small molecules of esters and amides through appropriate chemical reactions to form PEAs can avoid the reaction conditions controlling problem during the multiple formation of ester linkage or amide linkage to produce higher molecular weight of PEAs.The Michael-addition reaction is an atomic economical reaction for constructing C-X(X = C,O,N,etc.)single bonds and the reaction conditions are mild.Based on update advance of heter atoms Michael addition,a process about the synthesis of poly(ester amide)through oxa-Michael addition reaction of acrylamide with alcohol and aza-Michael addition reaction of amide with acrylic ester was proposed.The research contents and research results are as follows:At first,the effects of reaction temperature,catalyst and concentration on the oxaMichael addition were investigated using the solvent free reaction of methanol with acrylamide as a model.The optimized reaction condition are that methanol reacted with acrylamide at mole ratio of 1:1 at 40 °C for 4 h using 5 mol% activated potassium carbonate as the catalyst.The effects of alcohol structure on the activity were explored.The reaction activity and the conversion of primary alcohol is high(57~99%).The reactivity and conversion of secondary alcohol is medium(7~58 %).As for tertiary alcohol and phenol,almost no reaction was observed.The intramolecular hydrogen bond can improve the reactivity of secondary alcohol.A series of mono-addition ?-alkoxypropionamides,diaddition ?,??-alkoxybispropionamides,tri-additions ?,??,???-alkoxytripropanamide have been synthesized by the reaction alcohol,diol or triol with acrylamide.Products were characterized by NMR,HRMS.The effects of reaction temperature,concentration,catalyst and reaction time on the aza-Michael addition were investigated using the aza-Michael addition reaction of ?-methoxypropionamide and acetamide with butyl acrylate as the model.The optimized reaction condition are that ?-methoxypropionamide reacted with butyl acrylate at mole ratio of 1:1.5 at 160 °C for 10 h using 10 mol% activated potassium carbonate as the catalyst.At optimized reaction condition,poly(ester amide)s was synthesized by reaction of ?,??-(ethylenedioxy)bispropionamide with 1,6-hexanediol diacrylate with the yield of 57~74 %.The side reaction of reverse Michael-addition reaction and amide-ester exchange reaction are also observed during the aza-Michael addition of amide with acrylate.