N-acyllactams

N-Acyllactams (NAL) 11 represent a group of activators of CL polymerization that have been studied in depth, mostly in combination with alkali salts of lactams, and CLMgBr. The most relevant reports have focused on the kinetics, the degree of polymerization of the polyamide (P), the yield (conversion), transformation of the growth centers and the participation of side reactions, both in isothermal and adiabatic regimes and in the temperature range of 100 to 240 C [7-10]. 

The typical activation energy of polymerization is about 70 kj moTL At polymerization temperatures above the melting temperature of polymer, the polymerization reaches the equflibrium content (-90%) of polymer within a few minutes however, prolonged heating of the polymerization mixture causes degradation, which is seen as a rapid decrease in the molar masses. 

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N-acyllactams 28,465 Azomethine-type complex salts 19,744 suppl. 26 a-Azomethinioamidininm salts... 

Cuprous chloride ethyldiisopropylamine N-Acyllactams from carboxylic acid chlorides... 

Without additional reagents N-Acyllactams from 0-alkyllactims s. 21 y 483... 

The ring carbonyl carbon atom in the product (III) is much more strongly activated towards nucleophilic attack than that in the monomer because of the second carbonyl group bonded to the ring nitrogen atom (i.e. (Ill) is an N-acyllactam). Propagation can be represented generally by... 

Induction periods are often observed in the polymerization of lactams whilst the concentration of (III) increases. These can be eliminated by inclusion of acylating agents (e.g. acid halides and anhydrides) that react rapidly with the lactam to form N-acyllactams which then propagate... 

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