Preparation Of Long Chain Alkyl Naphthalene Base Oil And Its Lubricating Performance

Long-chain alkyl naphthalenes（ANs）belong to alkyl aromatic hydrocarbons,which can be prepared from naphthalene and olefins by Friedl-Crafts reaction.Alkyl naphthalene is used as the base lubricating oil,which is classified as class V lubricating base oil.It has high flash point and excellent thermal stability.When combined with other base lubricating oils,high-quality lubricating oils can be obtained.In this project,naphthalene and long-chainα-olefin（decene,dodecene,tetradecene,hexadecene）were selected as starting materials.Long-chain alkylnaphthalenes obtained by Friedl-Crafts reaction.The effect of process conditions on reaction yield was systematically studied,and the effect of alkyl substituents on lubricating properties was tested.Taking poly-α-olefins（PAOs）as the reference and blending object,the relationship between the ratio of ANs and PAOs and the lubricating performance of oil was studied.The obtained results had certain reference value in the synthesis and utilization of ANs.The main contents and conclusions are as follows:1.In this paper,suitable solid acid catalysts were screened out from molecular sieves and resins.The strong acidity of the resin promoted the occurrence of side reactions,which lead to a decrease in the selectivity of the target product.In contrast,the use of molecular sieves can obtain higher product yields,so molecular sieves were selected as the reference object for condition optimization.2.For the alkylation reaction of naphthalene and long-chain olefins,a most suitable molecular sieve type USY15 was screened through experiments.Compared with other molecular sieves,USY15 had higher acidity and more suitable pores,so the product yield was higher.We used USY15 as the catalyst to investigate the effect of catalyst dosage,molar ratio of naphthalene to olefin,reaction temperature and reaction time on the results of the catalytic reaction.The results show that under the optimal conditions,the olefin conversion is more than 99%and the selectivity of the target products is more than 93%.3.Combined with the analysis of the characterization test（Py-IR,NH₃-TPD,XRD,BET,SEM）results,it was found that the content of medium-strength acid and the content of B acid of the catalyst were important factors affecting the reaction results.4.This experiment took the series of long-chain alkyl naphthalene products（decyl naphthalene,dodecyl naphthalene,tetradecyl naphthalene,hexadecyl naphthalene）obtained above as the object,and systematically study the lubrication of this series of long-chain alkyl naphthalenes performance（density,kinematic viscosity,pour point,aniline point,flash point,fire point,oxidation stability,abrasion performance）.The results showed that the viscosity of the product was positively correlated with the length of the alkyl chain,the pour point of the product was lower than-40°C,and the lightning and flash points were higher than 160°C.Further,I selected tetradecyl naphthalene and cetyl naphthalene with better performance,and blended it with PAOs.It was found that the viscosity of the product increased after blending with PAOs,which facilitated its use.