DITHIOPHOSPHORIC ACIDS DERIVATIVES AS EP AND ANTI-WEAR ADDITIVES FOR TRANSMISSION OILS

Abstract

The article is devoted to a current problem - the synthesis of new compounds and their study as anti-wear and proto-pressure additives for lubricating oils. The purpose of this work is to obtain sulfur-phosphorus-containing compounds that could have tribological properties. Based on literature data and experience in this field, the authors synthesized derivatives of dithiophosphoric acids, which were further studied as extreme pressure and anti-wear additives for lubricating oils. The synthon for the synthesis of compounds was the sodium salt of diisopropyl and allyl dithiophosphoric acids, obtained by reacting the corresponding dithiophosphoric acids with a 40% solution of sodium hydroxide. By reacting the sodium salt of diisopropyl, sodium allyl dithiophosphate with toluene sulfonamide, obtained by reacting toluene sulfonamide with 5-phosphorus chloride, toluene sulfonisopropyl and allyl dithiophosphates were obtained. The resulting compounds have high extreme pressure properties. It has been shown that the extreme pressure properties of the compound depend on the structure of the fragments included in the compound. You should pay attention to the calculated indicator scuff index (Si), which indicates the effectiveness of extreme pressure properties; the higher this indicator, the higher the extreme pressure properties. 4-phenoxycarbonyl methyl ester of diispropyl dithiophosphoric acid was obtained by reacting the sodium salt of diisopropyl dithiophosphoric acid with phenyl chloroacetate; similarly, by adding 5-methyl-2-hydroxy-γ-chloroacetophenone to the diisopropyl dithiophosphate salt, 5-methyl-2-hydroxyphenylcarbonyl methyl ester of diisopropyl dithiophosphoric acid was obtained. These compounds also have high extreme pressure properties; in addition, they are superior to toluene sulfonic acid derivatives of dithiphosphoric acids in anti-wear properties, which is fully explained by the large amount of sulfur in the composition of the latter. The structure of all synthesized compounds was proven by IR spectral analysis, the study of physicochemical properties and elemental analysis. Extreme pressure and anti-wear properties were studied on a four-ball friction machine (FFM-1). The evaluation of extreme pressure properties was carried out according to the load wear index (LWI), according to the critical load (CL) and according to the welding load (WL), anti-wear properties by the diameter of the wear scar (Wd).