Synthesis of Fluorinated ZDDP Compounds

Abstract

Volatile degradation products of zinc dialkyl dithio phosphate (ZDDP) composed of phosphorus and sulfur compounds reduce the efficiency of catalytic converters resulting in harmful emissions. A unique way of reducing ZDDP level while maintaining good antiwear performance has been achieved by reacting a novel additive FeF3 with ZDDP. The objective of this research is to examine the chemical interactions between ZDDP and FeF3 that yield the new chemical species responsible for the improved wear performance. The approach adopted involves studies of thermal degradation products of ZDDP that are formed in presence and absence of FeF3. These intermediate products are responsible for the formation of protective tribofilms on the surface. Nuclear Magnetic Resonance Spectroscopy (31P and 19F) has been principally used to identify these products. Results have indicated the formation of new fluorinated phosphorus compounds formed as ‘early intermediate’ products in the reaction between ZDDP and FeF3. The chemical differences observed were used to justify the improved tribological behavior of the new fluorinated ZDDP compounds in comparison to ZDDP.