Boron Thiophosphite

The compound was synthesized from Triton X-100, diethyl phosphite, boric acid, diethanolamine, and formaldehyde. The method of synthesis has been described in detail (26). 

The results of the tests demonstrated that the boron-containing thiophosphite derivative is in fact a high performance and multi-fimctional water soluble lubricant additive that was able to remarkably improve the extreme pressure, friction reduction, anti-wear, anticorrosion, and the rust inhibiting properties of the base liquid when added at a low concentration, smaller than 3%. 

Based on a performance comparison of boron-containing thiophosphite derivative and thiophosphite, whose chemical structure is similar to that of boron-containing thiophosphite derivative but without boron, several conclusions were drawn  

The boron element existing as alkanolamine borate group could greatly improve the extreme pressure, anti-wear, and anh-rust performance of boron-containing thiophosphite derivative, especially the anti-rust performance, but only a small effect on the friction reducing and anticorrosion properties were shown. 

Based on the characterization and analysis of the worn surfaces, it has been proposed that the anti-wear mechanism consists of the prepared compound boron-containing thiophosphite derivative reacting with the steel surface during the friction process to generate a protective film mainly composed of phosphate, sulfide, sulfate, organic amine, and B2O3 (25). 

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A water soluble boron-containing thiophosphite derivative was synthesized, and its tribological, anticorrosion, and anti-rust properties as an additive for the base liquid of water-glycol hydraulic fluid were evaluated in detail (25). The compound is shown in Figure 4.7. 

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