Abstract: Process for the preparation of quaternary ammonium compounds, by preparing a mixture of a tertiary amine and a liquid reaction vehicle and adding an alkyl halide to the mixture to produce a quaternary ammonium halide, the liquid reaction medium being a liquid, low volatility, substantially non-toxic diluent having a vapor pressure not greater than about 1 mm. Hg at a temperature of 25.degree. C. and preferably being a fatty acid or a fatty acid mono-, di-, or triglyceride, a mineral oil, or 2-ethylhexanol wherein the alkyl groups comprising the fatty acids or the triglycerides have from about 10 to about 24 carbon atoms, the quaternary ammonium compounds being particularly suited for uses such as deinking of paper in conjunction with appropriate clays, surfactants, flotation agents, anti-static agents and biocides.