High-Speed Microwave-Promoted Direct Poly-amidation Reactions of Bulky Chiral Dicarboxylic Acide with Different Aromatic Diamines in Imidazolium Types Ionic Liquid as a Reaction Medium

Abstract

A comparison of ionic liquid (ILs) and volatile organic solvent as a reaction medium under microwave irradiation in the synthesis of novel organosoluble polyamides (PAs) is discussed. High polarities of the ILs make them an efficient substrate for quick heating under microwave irradiation. Direct polyamidation of our synthesized chiral dicarboxylic acid monomer (9), with several aromatic diamines was performed under microwave irradiation in different media, such as IL/triphenyl phosphite (TPP) or TPP, N-methyl-2-pyrrolidinone, pyridine and calcium chloride. The polymerization reactions occurred rapidly under microwave irradiation and produced a series of novel PAs having inherent viscosities of 0.36–0.85 dl/g and high yields. These aromatic PAs had useful levels of thermal stability associated with their relatively medium-high glass-transition temperature (155–168°C), 10% weight-loss temperatures in excess of 385°C and char yields at 800°C in nitrogen higher than 56%. In order to see the efficiency of microwave irradiation conjugated with ILs, this method was compared with polycondensation of this monomer in N-methyl-2-pyrilidone under microwave irradiation and the results are comparable.

Keywords:

• AMINO ACID
• IONIC LIQUID
• MICROWAVE HEATING
• POLYAMIDATION
• ORGANOSOLUBLE POLYMER
• GREEN TECHNOLOGY