Study On Synthesis And Properties Of Pentaerythritol Ester Lubricant Base Oil

As a component of ester lubricant base oil,neopentyl polyol ester has not only excellent viscosity and temperature properties,high and low temperature performance,thermal oxidation stability,but also good biodegradability and environmental friendliness.Pentaerythritol ester is a typical representative of the neopentyl polyol ester.The traditional synthesis of neopentyl polyol ester is mostly catalyzed by acidic or basic catalysts.However,the use of those catalysts will bring many problems,such as equipment corrosion,environmental pollution and product post-processing difficulties.Therefore,the acid free esterification process was explored.In order to improve the performance of synthetic ester,the isomerization of the raw materials was carried out.And we have also explored the regularity of isomerization reaction.Besides,a new process for the preparation of synthetic esters,which was named as self-catalyzed degassing esterification,was determined by the investigation of the synthesis of pentaerythritol isostearate.In addition,the products were also separated and purificated,and the purified product was analyzed by physical and chemical properties.In the process of isomerization,a series of experiments have been carried out in a autoclave.The isomerization process was optimized by the investigation of reaction factors.The properties of the catalysts were characterized by XRD?BET?TPD?Py-IR.In addition,the effect of three kinds of zeolite catalysts ZSM-5,ZSM-35,SAPO-11 was compared,results showed that ZSM-35 which was modified by hydrochloric acid had the best catalytic effect,and higher temperature,reaction time were beneficial to this reaction in a certain extent.When the amount of catalyst 5%,the reaction temperature 270?,reaction time 6 h,the amount of water 2%,oleic acid conversion rate reached 90%,isostearic acid yield can reach as high as 76.73%.For the preparation of pentaerythritol ester,the self-catalyzed degassing esterification is avaiable,firstly,the proper reaction device was designed,and then single factor method and orthogonal test were respectively used to optimize the synthesis process.The results show that in a certain range,higher temperature,longer reaction time and increasing the mole ratio of acid to alcohol is favorable to the synthesis of pentaerythritol ester.The optimal esterification conditions were as follows: system pressure 0.05 MPa,reaction temperature 220?,molar ratio of acid and alcohol to 4.3:1,reaction time 7 h.Under this condition,the degree of esterification reached 95.9%.The decolorization process and deacidification process of the product were determined through the purification of the product,that is,the separation and purification process of the product.The decolorization process were investigated by molecular distillation and active carbon adsorption on the decolorization products,and compared the crude acid removal of molecular distillation and vacuum distillation,the depth of the use of basic oxides.The results show that activated carbon exhibits the best decolorization effect,molecular distillation shows the better separation effect and MgO adsorption method was more suitable for deacidify refining.The kinetic of pentaerythritol ester synthesis was carried out,and the composition and content of products were determined on LC.Through analysis of the relationship between product distribution and reaction time,we speculated continuous reaction type was the reaction path of in the synthesis progress of pentaerythritol ester.