The Application Of Heteropoly Acid (salt) Catalyst In Esterification Reaction

Ester compounds as an important fine chemical were widely used in medicine, resin,material, coating material, food-stuff, solvent, plasticizing production process. In recent years,with scientific and technical prompt developing and human being living standard improving,the demand of ester compound was increasing greatly.Traditional ester technology needs high equipment technical requirements, harsh reactioncondition, long reaction times, and many by-products. In addition, It will produce a largeamount of waste acid in production process. The traditongal ester method exits manyshortcomings such as complex separation methods, high costs, catalyst without recycleproperty. And all of this will make irretrievable loss for environment. Solid heteropoly acid, agreen environment friendly, safety high efficiency new catalysts, has attached great attentionof vast scale researchers.A series of solid heteropoly acids with different quaternary ammonium salts wereprepared by different methods, and species present in the catalysts were characterized bydiverse physicochemical techniques, such as IR, XRD, SEM, BET and so on. In ester reaction,we discussed the catalyst activities an increased esterification rate in different ways usingacetic acid and ethanol as reaction raw stuff and moderate catalyst in mild reaction conditions.The main contributions of the thesis are as follows:1. With phosphotungstic acid and cesium carbonate as materials, we prepared a series ofdifferent cesium atoms replaced cesium phosphotungstic acid catalysts, and the catalysts werecharacterized with XRD, IR, SEM and BET techniques. It shows the catalyst still keepKeggin-structure without obviously change. The react activity of catalyst was discussed using0.1mol acetic acid and0.1mol ethanol as reaction raw stuff, with0.2g catalyst, in80℃for5hours. The effects of catalyst dosage, reaction time, acid alcohol mole ratio, catalyst recycleproperty on the result of the experiment had been studied and the esterification rate can reach95.04%in optimal conditions. 2. A series of silica supported vanadium substitutional molybdophosphate catalysts withdifferent loading were prepared by etherification method and characterized with XRD, IR andSEM techniques. It shows the catalyst still keep Keggin-structure without obviously change.The react activity of catalyst was discussed using0.1mol acetic acid and0.1mol ethanol asreaction raw stuff, with0.2g catalyst, in80℃for5hours. The effects of catalyst dosage,reaction time, acid alcohol mole ratio, catalyst recycle property on the result of the experimenthad been studied and the esterification rate can reach91.80%in optimal conditions. In addition,the catalyst has high stability and high reaction activities for many esters.3. The catalyst ZrO2-Cs1H4PW10V2O40was prepared by impregnation method, using ZrO2as supporter and characterized with XRD, IR and SEM techniques. It shows the catalyst stillkeep Keggin-structure without obviously change. The react activity of catalyst was discussedusing0.1mol acetic acid and0.1mol ethanol as reaction raw stuff, with0.2g catalyst, in80℃for5hours. The effects of catalyst dosage, reaction time, acid alcohol mole ratio, catalystrecycle property on the result of the experiment had been studied and the esterification rate canreach96.44%in optimal conditions. In addition, the catalyst has high stability and highreaction activities for many esters.4. A series of phosphotungstic acid modified by Ammonia compounds were prepared andcharacterized with XRD, IR and SEM techniques. It shows the catalyst still keepKeggin-structure without obviously change. The react activity of catalyst was discussed using0.1mol acetic acid and0.1mol ethanol as reaction raw stuff, with0.2g catalyst, in80℃for5hours. The effects of catalyst dosage, reaction time, acid alcohol mole ratio, catalyst recycleproperty on the result of the experiment had been studied and the esterification rate can reach91.49%in optimal conditions. In addition, the catalyst has high stability and high reactionactivities for other esters.5. Phosphotungstic acid or phosphomolybdic acid modified by picolinic acid withdifferent Acid alcohol mole ratio were prepared and characterized with XRD, IR and SEMtechniques. It shows the catalyst still keep Keggin-structure without obviously change. Thereact activity of catalyst was discussed using0.1mol acetic acid and0.1mol ethanol asreaction raw stuff, with0.2g catalyst, in80℃for5hours. The effects of catalyst dosage, reaction time, acid alcohol mole ratio, catalyst recycle property on the result of the experimenthad been studied and the esterification rate can reach91.49%in optimal conditions. In addition,the catalyst has high stability and high reaction activities for many esters, and the catalysisactivities without obviously change by five recycle using.