GB849951A - Improved process for the oxidation of slack waxes - Google Patents

Abstract

Slack waxes are oxidised to slack wax acids by passing a stream of air under a pressure of 25-205 p.s.i.g. through the molten wax in the presence of a minor proportion of carboxylic acids and 0,5-4,4% wt. of a water-soluble permanganate salt at below 150 DEG C. until the product has an acid number of 40-100. A slack wax is defined as the wax containing more than 0,3% wt. of sulphur and more than 3% wt. of lubricating oil obtained from a deasphalted broad or narrow lubricating oil cut. The carboxylic acids may be C12-42 saturated aliphatic acids or mixtures thereof, such as are obtained in the process of the present Specification or of Specification 816,670.ALSO:Aqueous alkaline bitumen emulsion compositions contain slack wax acids obtained by oxidising slack wax by passing a stream of air under a pressure of 25-205 p.s.i.g. through the molten wax in the presence of a minor proportion of carboxylic acids and 0.5-4.4% wt. of a water-soluble permanganate salt at below 150 DEG C. until the product has an acid number of 40-100. The carboxylic acids may be C12-C42 saturated aliphatic acids or mixtures thereof such as are obtained by the above oxidation process or by the process of Specification 816,672 [Group IV(b)]. A specified composition contains bitumen 15-65 parts by weight, slack wax acids 2-6 parts, and water 35-85 parts, NaOH 0.03-0.15 parts. The emulsion may also contain 0.01-1 parts of a bitumen emulsion stabilizer, such as a Tall oil or neutralised Swedish liquid rosin. Preferred emulsions have a particle size range of 1-6 m and a viscosity of 5-7 Engler at 20 DEG C. The emulsions may be made by passing the bitumen and slack wax acid (at 230-270 DEG F.), aqueous NaOH, and stabilizer (at 160-190 DEG F.) through a colloid or Hurrel mill.