Synthesis And Application Of Glycerol Trioleate

The control index of sulfur content in automotive diesel becomes increasingly strict.With the deep hydrogenation of diesel,the lubricating property of the diesel decreases,which has bad influences on the engine oil pump and cylinder.Oleic acid glycerides are a kind of green lubricity improvers for diesel,because they are low toxicity,easy degradation and good lubricity.Especially,glycerol trioleate is the best,which has a wider applicability for diesel.Chambroad Chemical Industry Research Institute has also developed an ester product of this kind,but the preparation method has some drawbacks,such as equipment corrosion,waste materials,and the unsteady of product quantity.Two reasons have be found according to investigation.The first is that the content of saturated fatty acids in materials is too high.The other is that the catalyst used in the esterification reaction has negative effects on the refinement of the final products.Therefore,it is particularly important to develop a more economical and green esterification process.Firstly,in this paper,three kinds of plant oleic acid,whose cloud point and saturated fatty acid content(about 10%)are high,were purified by three-grade-filtration at a constant low temperature.After purification,the purity of unsaturated fatty acids reached more than 99%,the freezing point decreased from-1℃ to-19℃,and the cloud point decreased from 3℃ to-11℃.The product yield of these three plant oleic acids were all over 80%.The indicators were better than the import tall oleic acid.By comparing unsaturated fatty acids’ purity,cloud point and material price,the refined cottonseed oleic acid was selected as the best raw material for the synthesis of ester lubricity improvers.Secondly,we studied the esterification process and determined the conditions of reaction.(1)P-toluenesulfonic acid was selected as a better kind of catalyst than molecular sieve.(2)To optimize the catalyst,we prepared an activated aluminium oxide supported p-toluene sulfonic acid catalyst,which has high catalytic activity,less pollution,no corrosion equipment and simple post-processing.(3)We optimized the conditions of the esterification reaction,including the amount of catalyst,reaction temperature.The optimum process conditions were determined as follows: the reaction temperature,reaction time,addition of catalyst,and the molar ratio of acid to alcohol were 150 oC,3h,5%,and 2.85:1.Under this conditions,the conversion could be as high as 98.5%.Finally,the pilot test was successfully completed using the refined cottonseed oleic acid under the above conditions.When the addition of production into the low sulfur diesel oil was 200 mg/kg,the diesel abrasion spot diameter could meet the request of national standard.It was also proved that the addition of this product into diesel was safety for the low temperature fluidity,oxidation stability,cetane number,etc.