New Organic Molybdenum Extreme Pressure Antiwear Synthesis And Application Performance

Extreme-expressure and antiwear additives which can improve machanical efficiency, reduce energy consumption and prolong machine's life-span, are important lubricating oil additves. In this thesis, a review has been made on the development history of several classes of EP&AW additives, especially on the research and development situation of molybdenum compounds as lubricating materials and EP&AW additives. The experimental section of this thesis involves the synthesis of a series of organic molybdenum compounds and the test of their properties as EP&AW additvies. The mechanism of extreme-pre--ssure, antiwear and friction-reducing by these organic molybdenum compounds have also been discussed.2-chloriethnol, phosphorus pentasulphide and sodium molybdate as starting material, a new organic molybdenum compound, molybdenum di( -chloriethyl) dithiophosphate (MoDCTP) which contains S, P and Cl simutaneously has been synthesized; Isopropanol, phosphorus pentasulphide and sodium molybdate used as starting material, molbdenum diisopropyl dithiophosphate(MoDTP) has been synthesized; molybdenum dibutyl dithiocarbamte(MoDTC) has been synthesized from di-n-butylamine, carbon disulfide and sodium molybdate. The reaction conditions of these organic molybdenum compounds such as reaction temperature, reaction time and molar ration of starting materials have been optimized.The three compounds have been characterized by means of infrared spectra, melting-point apparatus and elemental analysis. Some of their physical and chemical constants which are first reported are as follows: MoDCTP is a brown solid with a melting point of 157~159 C, The molybdenum content is 24.2% ; MoDTP is yellow solid with a melting point of 177- 178 C, The molybdnum content is 26.4%; MoDTC is also a yellow solid with a meting point of 270 ~ 272 "C, and its molybdenu content is 26.8%.The extreme-pressure, antiwear and friction-reducing properties of these organic molybdnum compounds have been evaluated withfour-ball machine. The research shows that these organic molybdenum compounds can well improve the the extreme pressue, antiwear and antifriction properties of base oil. The comparison of oil containing 1.0% of additive with base oil(containing no additive) is indicated as follows:PB : MoDCTP 114Kg, MoDTP 88Kg, MoDTC 76Kg, which increase the PB value of base oil by 4.5 , 5.2 and 6.7 times respectively.WSD: MoDCTP 0.60mm, MoDTP 0.42mm, MoDTC 0.42mm, which decrease the WSD value of base oil by 52.4% , 66.7% and 66.7 % respectively. : MoDTC 0.058, MoDTP 0.067 , MoDCTP 0.046, which decrease the value of base oil by 47.3 %, 58.2% and 39.1% respectively.The research data also shows that MoDCTP is better than both MoDTP and MoDTC in extreme-pressure capability as well as in friction-reducing capability. As far as antiwear capability is concerned, MoDCTP is equivalent to MoDTP but better than MoDTC.The mechanism of extreme-pressure, antiwear and friction-reducing by these organic molybdenum compounds have also been discussed, showing that on the rubbing surface a transfer film composed of MoO3, MoS2 and FePO4 was formed as a result of decomposition of organic molybdenum compounds.