Enhancing effect polyamide

It has already been reported that aliphatic diesters with hydroxyl groups such as tartrate and mucate could easily react with diamine even at room temperature to form the corresponding polyamides. The rate enhancement effect of these hydroxyl groups is presumably ascribed to... 

Likewise, the luminescence properties of many analytes can be altered in the presenoe of surfactant aggregates (4,7.,8.). Consequently, addition of micelle-forming surfactants (present either in the LC mobile phase or added post-column) can improve the sensitivity of fluorimetric LC detectors (49,482). Micellar spray reagents have been utilized to enhance the fluorescence densitometric detection of dansylamino acids or polycyclic aromatic hydrocarbons (483). The effect was observed for TLC performed on cellulose or polyamide stationary phases with the micellar spray reagent being either CTAC, SB-12, or NaC (483). More recently, use of nonionic Triton X-100 has been found to improve the HPLC detection of morphine by fluorescence determination after post-column derivatization (486) as well as improve the N-chlorination procedure for the detection of amines, amides, and related compounds on thin-layer chromatograms (488). 

The first step in the condensation reaction is the attack of the amine nitrogen at the carbonyl carbon of the dicarboxylic acid. The local electron density at the aromatic amine nitrogen is greatly reduced by participation of the lone pair electrons with the aromatic ir-cloud, whereas the local electron density of the aliphatic counterpart is enhanced by the inductive effect of aliphatic hydrocarbon. This leads to a significant difference in the polycondensation reaction rate between aromatic polyamides and aliphatic polyamides. 

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