Study On The Synthesis And Performances Of Diesel Fuel Lubricity Improver With Low Acid Value

In the view of friction and wear lubrication problem of low sulfur diesel fuel pump, at present the most economic and efficient way to add diesel lubricity improver to solve the diesel lubrication problem. And the more hydroxyl alcohol ester is an ideal lubricating additive. At present, the more hydroxyl alcohol ester is synthesized mainly by esterification reaction using fatty acids or oil and polyols. The process of synthesis is complex, and strong inorganic acid and alkali catalyst adopted will corrode the equipment, which can not be reused and pollute the environment. So it is necessary to improve the traditional process.In this work, two new imidazole basic ionic liquids, [Bmim]OH and [Bmim]Im, were synthesized and characterized by NMR. The thermal stability of the two as-prepared ionic liquid catalysts was measured by thermogravimetric analysis. The catalytic performance of the two ionic liquid catalysts for the synthesis of fatty acid monoglyceride by the transesterification reaction between vegetable oil and glycerol was conducted and compared with NaOH as catalyst. It turned out that the thermal stability of [Bmim]Im was far better than that of [Bmim]OH. [Bmim]Im is the most efficient catalyst and the yield of fatty acid monoglyceride is much higher than NaOH and [Bmim]OH as the catalyst at the same conditions. The ionic liquid catalyst provides a green new synthetic route for synthesis of fatty acid monoglyceride, which is easy to be separated from the product and can be reused.The transesterification reaction between vegetable oil and glycerol was conducted for the synthesis of fatty acid monoglyceride catalyzed by [Bmim]Im. The influencing factors, vegetable oil, temperature, reaction time, ratio of raw materials, dosage of catalyst and reuse influence on the yield of fatty acid monoglyceride were investigated by the single factor experiment. It turned out that soybean oil is an ideal oil. The optimum reaction conditions were obtained as follows: temperature 190 ℃, reaction time 3 h, ratio of raw materials 6, and the dosage of catalyst 10 % weight of the oil. Under the optimum conditions, the reaction conversion and the yield of fatty acid monoglyceride reached 93 % and 64.46 % respectively, and the catalyst can be reused 5 times without obvious decrease of the yield of fatty acid monoglyceride.The three kinds of lubricity improvers, ricinolic acid, fatty acid methyl ester and fatty acid glycerin monoester, were experimented in the high frequency reciprocating engine(HFRR) to examine the anti-wear performance of low sulfur diesel fuel. It turned out that all the three kinds of lubricity improver can meet the requirements of diesel fuel lubricity within the dosage of 200 μg·g-1(HFRR grinding spot diameter was below 460 μm). The order of lubrication effect was that, ricinolic acid> fatty acid glycerin monoester> fatty acid methyl ester. And the compatibility of fatty acid glycerin monoester and diesel additives was also conducted. It turned out that the fatty acid glycerol ester was an ideal lubricating additive, which has low acid value and good compatibleness with diesel stabilizer, low temperature flow improver and sixteen octane of the diesel.