Acid Chloride Route

The acid chloride method comprises the condensation of aromatic tricarboxylic acid chloride with aromatic diamine. This method is subdivided 

A typical example of the low temperature homogeneous solution polymerization method is the polymerization reaction at room temperature in a nonaqueous polar solvent such as DMAC.  

The low temperature precipitating polymerization method comprises the polymerization reaction in an organic solvent which is sparingly soluble in water, such as methyl ethyl ketone, and in an aqueous solvent by using triethylamine as an acid acceptor. This reaction is a kind of interfacial polymerization method.  

There are currently two popular commercial methods to synthesize polyamide-imides. One is the acid chloride route, and the other is the isocyanate route. The sjmthesis method used will determine and limit to some extent the applications in which the resultant polymer is used. The chemistry of these two methods is outlined helow. 

The earliest and one of the most well-known routes to polyamide-imides is through the two step-process involving the condensation of an aromatic diamine and TMAC (Fig. 12.2) [7, 8]. Reaction of the anhydride portion of TMAC provides an intermediate amic acid ( i). On the other end of the molecule, the acid chloride functionality reacts with aromatic amine to give the amide bond and hydrochloric acid (HCl) as a byproduct k. In the commercial preparation of polyamide-imides, the solution polymerization is carried out in a dipolar, aprotic solvent such as N-methylpyrrolidone (NMP), dimethylacetamide (DMAC), dimethyl-formamide (DMF), or dimethylsulfoxide (DMSO) at temperatures between 20 and 60°C [9]. 

The presence of the byproduct HCl in the solution polymerization requires it to be neutralized in situ or removed by isolating and washing it from the resultant polymer formed. Organic bases such as tertiary amines (triethylamine) have been used in situ, along with ethylene or propylene oxide, as acid acceptors in the reaction solution [10]. 

The amic acid intermediate is stable and may be isolated as such. After the solution reaction is complete, the polymer is recovered via precipitation. 

With a high concentration of amic acid groups along the polymer backbone, the polymer at this stage can be formulated into aqueous solutions with the aid of a tertiary amine, which reacts to create the ammonium salt of the amic acid [11], 

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Acid Chloride Reaction. In situations where the reactants are sensitive to high temperature or the polymer degrades before the melt poiat is reached, the acid chloride route is often used to produce the polyamide (47). The basic reaction ia the presence of a base, B , is as follows ... 

The acid chloride route of the Schotten-Baumann reaction can be carried out continuously [6] while completeness of the reaction can be assured by rapid recirculation of the reaction product [7]. These compounds are used in specialty applications, such as shampoos or soap-syndet toilet bars [8]. 

The protocol described above is a scaled-up modification of that reported earlier.7 The title compound has been prepared previously by a nickel-catalyzed cross-coupling,6 and by the organocerium/acid chloride route.6 The present procedure offers advantages in both convenience and yield compared to these other methods. 

This reversibility is a disadvantage in the preparation of an ester directly from an acid the preference for the acid chloride route is due to the fact that both steps—preparation of acid chloride from acid, and preparation of ester from acid chloride—are essentially irreversible and go to completion. 

The synthesis can be carried out in a number of ways perhaps the acid chloride route (Y=C1) is the easiest, with pyridine as catalyst and solvent. 

The use of the acid chloride route has the disadvantage of liberating corrosive hydrochloric acid but the advantage of being carried out by either a [12,13] solution [15] or a low-temperature interfacial process [16]. 

From 2,2-dideuteroalkylmalonic acids and half ester acid chlorides (Route b) 8-oxo-octadecanoic-l 1,11-1/2 and 11-oxo-octadecanoic-14,14-1/2 acid were obtained. [45]... 

Each amide can be prepared by treating the carboxylic acid with SOCI2 to form the acid chloride (Section 13.7) and then treating the acid chloride with an amine (Section 14.5A). Alternatively, the carboxylic acid can be converted to an ester by Fischer esterification (Section 13.6) and the ester treated with an amine to give the amide. Solution (a) uses the acid chloride route, solution (b) the ester route ... 

Also in this time frame, wire insulation producers began producing polyamide-imides using lower-cost isocyanate chemistry. This technology largely supplanted the acid chloride route for the wire enamel market. 

The earliest references to the acid chloride route came from Conix [5], Eareckson [7], Morgan and Kwolek [8], and a number of Russian investigators [9-16], specifically Korshak and Vinogradova. The procedure noted by Earecicson [7] involved Interfacial polycondensation vAiere the aqueous solution of the dialkali salt of Bisphenol A was contacted with a solution of aromatic acid chlorides in a water-insoluble solvent. An emulsifier was added and the solutions were rapidly mixed followed by coagulation of the... 

A series of l,r-oligoprolinoyl-feirocenes (5, 15-17) were obtained from 1,1 -ferrocenedicarboxylic acid (11), HOBt, EDC, and a series of oligoproline esters (Scheme 4) The monoproline derivative 5 was first obtained by Herrick via the acid chloride route. 

Benzoate plasticizers have been recognized since the 1940s as useful plasticizers for PVC. It was not until the mid-1950s, however, that benzoates useful in vinyl compositions were specifically identified and commercialized. Benzoate esters can be produced by direct esterification, transesterifleation, via the acid chloride route, or Schotten-Bauman reaction. The current preferred method for most benzoate esters... 

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