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Study On Sulfonic Resins Catalyzed The Hydroiysis And Transesterification Reaction Of Tannic Acid

Posted on:2018-05-04Degree:MasterType:Thesis
Country:ChinaCandidate:F D LiFull Text:PDF
GTID:2381330515466215Subject:Organic Chemistry
Abstract/Summary:PDF Full Text Request
Gallic acid and gallate esters,which are the kinds of importants fine chemicals,have widely been used in different kinds of fields in mondern society.With the expanding of industry and increasing development of the industry processing technology,the study on the synthesis of gallic acid and gallate esters,whether it is for the development of industry itself or enviromental protection,is very important.Gallic acid and gallate esters can be commercially synthesized by a traditional chemical catalysis means with such defects as high energy consumption and high corrosive environment?caused by concentrated sulfuric acid?.In order to develop a highly-efficient and environmentally-friendly catalysis process for this synthesize,sulfonic resin instead of liquid acids to catalyze the synthesis of gallic acid and one-pot bio-synthesis of gallate esters was studied in this paper and the obtained results are described as follows:1.The effect of polystyrene carrier and acid active sites-SO3H improvement.A15-Br were synthesized from the precursor Amberlyst 15by a typical halogenation reaction.Based on that,A15-Br-NO2 were synthesized from the precursor A15-Br by a nitration reaction.A15-Br-NO2 not only has a significantly improved thermal stability but has a the strength of acid.Furthermore,macroporous and low cross-linkig resin?ML-PS? were synthesized,which has excellent pore size and pore volume structure.Macroporous and low cross-linkig sulfonic resin?ML-SPS? were synthesized from the precursor ML-PS by a sulfonation reaction.2.The catalytic performance of Amberlyst 15,A15-Br,A15-Br-NO2 and ML-SPS sulfonic resin was checked on the hydroiysis of tannins?TA?.The results showed that these sulfonic resin for the hydroiysis reaction possessed good catalytic activity,and ML-SPS sulfonic resin was the best.In using ML-SPS sulfonic resin to catalyze the hydroiysis of TA,various reaction parameters such as reaction time,reactant ratio,the amount of catalyst were checked in details.Under the optimum reaction conditions,ML-SPS sulfonic resin catalyst gave 65.7% of hydroiysis yield and an relatively good stability.But a relative high catalyst amount?2.70 g? hampered its application.3.The catalytic performance of Amberlyst 15,A15-Br,A15-Br-NO2 and ML-SPS sulfonic resin was checked on the transesterification of TA.The results showed that these sulfonic resin for the transesterification possessed good catalytic activity,and ML-SPS sulfonic resin was the best.In using ML-SPS sulfonic resin to catalyze the transesterification of TA,the effect of various reaction parameters was checked in details.Under the optimum reaction conditions?catalyst 1.35 g,mole ratio of acid to alcohol 1:50,reaction temperature 125?,time 9 h?,octyl gallate?the yield of 83.2%? and dodecyl gallate?the yield of 81.7%? rapidiy and efficiently were synthesized from TA by transesterification reaction.ML-SPS sulfonic resin exhibited the excellent catalytic activity and recyclability,because of there is no water in the reaction system.But the transesterification yield of TA to lower alcohol is still improved.
Keywords/Search Tags:sulfonic resin, hydroiysis reaction, gallic acid, transesterification reaction, gallate ester
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