Standards Development

Scope

This proposal describes a GC method for determining the average relative molecular mass of aliphatic alkyl tri methylammonium chloride.

Purpose

Quaternary ammonium salt is an important cationic surfactant, which has a good adjustment effect and bactericidal effect, and is widely used in fabric softeners, disinfectants, shampoo and hair care products and other product formulations. aliphatic alkyltrimethylammonium chloride is the most basic and most commonly used quaternary ammonium salt surfactant, and the common products can be divided into cetyltrimethylammonium chloride and octadecylammonium chloride according to the different carbon chains of the main components, which are referred to as 1631 and 1831 in the industry.

When determining the cationic active ingredient content of aliphatic alkyltrimethylammonium chloride in surfactants or detergents, it is generally determined according to the two-phase titration method, which requires the average relative molecular mass of the active ingredient to be accurately quantified. The China light industry standard QB/T 1914-2013 describes a method for determining the average relative molecular mass of aliphatic alkyl trimethylammonium chloride by gas chromatography: the sample is pyrolyzed in a vaporization chamber to form aliphatic alkyl dimethylamine, and the average relative molecular mass of aliphatic alkyl dimethylamine is determined by its homolog distribution; The average relative molecular mass of aliphatic alkyl dimethylamine was then calculated by adding the molecular mass of chloromethane (CH3Cl) to the average relative molecular mass of aliphatic alkyl trimethyl chloride. This method standard has been published and implemented for more than ten years, and has been widely used in the surfactant industry, and has been verified and affirmed by surfactant manufacturers, downstream users and testing institutions.

In this proposal, the method is proposed to be developed as "Surface active agents—Determination of average relative molecular mass of aliphatic alkyltrimethylammonium chloride— Part 1: GC method".