膦酸酯离子液体在合成多元醇酯过程中的双重作用:从催化剂到合成酯的减摩抗磨添加剂

合成了两种膦酸酯类离子液体,用作三羟甲基丙烷(TMP)与油酸(OA)的酯化催化剂合成三羟甲基丙烷三油酸酯(TMPTO).结果表明:这两种离子液体均具有一定的催化活性和较高的产物(二酯和三酯)选择性.反应结束后,离子液体催化剂可完全溶于产物TMPTO中,在微动摩擦磨损试验机SRV-IV上评价其作为钢/钢摩擦副润滑油减摩抗磨添加剂的高温摩擦学性能;结果表明所合成的磷酸酯离子液体具有优异的减摩抗磨性能.采用扫描电子显微镜(SEM)及X射线光电子能谱仪(XPS)对磨斑表面进行了分析,结果表明所合成的膦酸酯类离子液体在高温下均表现出优异的摩擦学性能,源于膦酸酯类离子液体与金属基底发生了摩擦化学反应并形成了摩擦化学反应膜从而使该离子液体表现出优异的摩擦学性能.

Dual Role of Phosphate Ionic Liquids in Synthetic Ester Oil: from Synthetic Catalyst to Anti-Wear Additive

Two phosphate ionic liquids (ILs) were synthesized, and investigated as catalysts for the esterification of trimethylolpropane (TMP) with oleic acid (OA) to produce trimethylolpropane-trioleate (TMPTO) for the first time. Both of the two ILs showed significant catalytic activity and high selectivity to di- and tri- esters. The test results show that the ILs were fully miscible with TMPTO, and the tribological property of the ILs as antiwear additives for the steel/steel contact by an Optimol SRV-IV oscillating reciprocating friction and wear tester under high temperature. The two ILs prominently improved the friction-reducing and antiwear properties of the base oil. The morphologies of the worn steel surfaces were analyzed by scanning electron microscope and X-ray photoelectron spectrometer analysis to explore the lubrication mechanism. It is indicated that physical adsorption and tribochemical reactions occurred during the rubbing process with the generation of surface protective films, which prevented the metal-metal contact and reduced friction and wear.