テトラフェニルホウ素ナトリウムによる四級アンモニウム塩基の定量法について

抄録

A new convenient volumetric method was established for the determination of quaternary ammonium salts using sodium tetraphenylborate, with Methyl Orange as the indicator. This method can be applied for quaternary ammonium salts with a long chain of alkyl group, such as cetyltrimethylammonium bromide, laurylbenzyldimethylammonium bromide, etc. It was found that Methyl Orange combined with the quaternary ammonium salts and did not show its acid color even in acid solution but the color appeared at the end point when titrated with sodium tetraphenylborate. Based on these facts, a procedure was established after examination of various conditions, such as the effect of pH, selection of an indicator, and concentration of the titrant and the indicator. In this procedure, 10-20cc. of M/20 to M/1000 sample solution is adjusted to the suitable pH with hydrochloric acid after addition of a drop of M/200 Methyl Orange solution and titrated with M/20 to M/50 sodium tetraphenylborate solution until the acid color appears. Results obtained with this procedure on various kinds of quaternary ammonium salts agreed with those obtained by the potassium cadmium iodide method.