Lipase-Catalyzed Transamidation of Urethane-Bond-Containing Ester

Abstract

Significant improvement in mechanical properties and shape recovery in polyurethanes can be obtained by cross-linking, usually performed in a traditional chemical fashion. Here, we report model studies of enzymatic transamidations of urethane-bondcontaining esters to study the principles of an enzymatic build-up of covalent cross-linked polyurethane networks via amide bond formation. The Lipase-catalyzed transamidation reaction of a urethane-bondcontaining model ester ethyl 2-(hexylcarbamoyloxy)propanoate with various amines is discussed. A side product was formed, that could be successfully identified, and its synthesis reduced to a minimum (<1%). Furthermore, a noncatalyzed transamidation that is performed without CalB as the catalyst could be observed. Both observations are due to the known high reactivity of amines with urethane bonds.

Enzymatic transesterification of urethane-bond containing ester

“…Although enzymes, especially lipases, are successfully used for many reactions in organic chemistry and also for polymerizations [17][18][19][20][21][22][23][24][25][26][27][28][29], they are not used so far for industrial polyurethane synthesis, as this method is still not efficient compared with that of classical production processes. However, regarding the demand of new variable polyurethanes with new properties for different applications, the interest of enzymes as biobased and environmentally friendly catalysts steadily increases [30,31].…”