Construction Of MMT Supported Catalysts And Its Catalytic Preparation Of Long Chain Fatty Acid Esters

The purpose of this research was developing montmorillonite supported catalysts by dipping method.The catalysts were applied to the esterification reaction to prepare long chain fatty acid esters.Specifically,the catalysts preparation process,characterization and its catalytic preparation of glyceryl isostearate and branched chain oil was studied in the paper.The montmorillonite supported catalysts were prepared by dipping method and characterized.A series of modified montmorillonite catalysts were prepared by dipping montmorillonite into various inorganic salt solutions.Using the esterification of isostearic acid and glycerol as probe reaction,the catalytic performance of different catalysts were investigated.The experimental results showed that the modification effect of nickel sulfate on montmorillonite was the best.And then the conditions of preparing montmorillonite supported nickel sulfate catalyst?Ni-MMT?was investigated systematically.The optimum preparation conditions of catalysts were attained as follows: concentration of Ni²⁺ was 0.2 mol/L,dipping temperature was 50?,dipping time was 24 h and the ratio of liquid to solid was 12 m L/g.The structure,chemical components and performance of catalysts were characterized by FT-IR,XRD,EDS,N2 physical adsorption and TGA etc.technique.The results of characterization demonstrated that,compared to the starting montmorillonit,the montmorillonite supported catalysts had apparent Br?nsted acid sites and Lewis acid sites,and the acidity was enhanced.In addition,the montmorillonite supported catalysts has drastically increased interlayer spacings,well-retained crystilline types,increased specific suface area and pore volumens,and reduced average pore diameters.Furthermore,the montmorillonite supported catalysts had evenly distributed inorganic salt and good thermal stability.The glyceryl isostearate was prepared by catalyst of montmorillonite modified with nickel sulfate,and the esterification rate was calculated by measuring the acid value of the raw material and the product.Using the esterification rate as standard,mole ratio of acid to alcohol,amount of catalyst,reaction temperature and reaction time were investigated by single factor experiments.According to the orthogonal experiment,the optimized reaction conditions were found as: acid / methanol molar ratio 5.5:1,catalyst dosage 4%?based on the glycerol mass?,reaction temperature 180? and reaction time 7 h.Under these conditions,the esterification rate was more than 94%.Meanwhile,the products were identified by FT-IR,LC-MS and TGA.The results of FT-IR and LC-MS indicated that the product was mainly composed of triglyceride.The TGA revealed that the product had good thermodynamic stability.And some physical-chemical parameters of the products were determined,the Acid Value of purified product was 2.58 mgKOH/g,Hydroxyl Value was 8.91 mgKOH/g,Saponification Value was 198.38 mgKOH/g,Viscosity Index was 143,Refractive Index was 1.471?25??and Pour Point was-20?.Using oleic acid as raw material,the preparation of hydroxy oil by methyl esterification,epoxidation,ring opening reaction.And the reaction conditions of the preparation of hydroxy oil by catalyzing epoxy oil and isooctanol were optimized.According to the single factor test and response surface analysis,the optimized reaction conditions were found as: the catalyst dosage 3.7%?based on the epoxy oil mass?,alcohol/oil molar ratio of 3.4:1 and temperature at 90? for 12 h,the open-loop conversion rate reached more than 99%.Afterwards,the branched chain oil was prepared by esterification of hydroxy oil and isostearic acid catalyzed by Ni-MMT.According to the single factor test,the optimized reaction conditions were found as: acid/methanol molar ratio 1.5:1,catalyst dosage 7.5%?based on the hydroxy oil mass?,reaction temperature 190? and reaction time 8 h.Under these conditions,the esterification rate was more than 85%.The main structure of the hydroxy oil and branched chain oil was determined by IR and MS analysis.The TGA revealed that the two products had good thermodynamic stability.And some physical-chemical parameters of the products were determined.Using the HFRR to evaluate the lubrication performance of the glyceryl isostearate and branched chain oil,the results showed that the products can meet the requirements of the use of lubricating base oil.