Benzyltrialkylammonium salts

The benzyltrialkylammonium salts (R3N,CH2,Ph Cle) are prepared similarly 3 g of redistilled benzyl chloride replaces the methyl toluene-p-sulphonate. 

The catalytic carbonylation of benzylic halides to arylacetic acids has been improved by using two-phase systems under phase-transfer conditions [29]. Usually the reactions were performed with an excess of base in a biphasic system with a metal catalyst in the organic phase. As phase transfer catalysts surfactants are used, which appear to play an important transport function to move the cobalt carbonyl salt from the aqueous phase to the organic droplets (cf. Section 3.2.4). While the structure of the phase transfer co-catalyst was being studied it was observed that benzyltrialkylammonium salts were easily carbonylated. In some cases the yields of arylacetic acids are higher compared with the carbonylation of the corresponding benzyl halides [30]. 

Shirai, N., Sato, Y. Ylide rearrangement of benzyltrialkylammonium salts the improved Sommelet-Hauser rearrangement. J. Org. Chem. 1988, 53, 194-196. 

A widely accepted titrant for two-phase titration of cationics is tetraphenylborate ion (88). The titration depends upon the surfactants maintaining their ionic character, and therefore the pH is critical. All common cationic surfactants can be titrated at pH 3, using methyl orange as indicator. At pH 10, all quaternaries can be titrated, but other amines are not sufficiently ionized. At pH 13, only certain quaternaries can be determined, but these include the commercially most abundant products alkyltrimethyl- and dialkyldimethylam-monium and benzyltrialkylammonium salts. Bromophenol blue is a suitable indicator for the titrations at pH 10 and 13. 

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