Font Size: a A A

Design, Preparation Of Novel Solid Acid Catalysts And Their Application In Alkylation Reactions

Posted on:2005-10-11Degree:DoctorType:Dissertation
Country:ChinaCandidate:B ChenFull Text:PDF
GTID:1101360122493552Subject:Analytical Chemistry
Abstract/Summary:PDF Full Text Request
The reaction of benzene alkylation with long chain olefin and diphenyl ether (DPE) alkylation with olefin are two important industrial reactions. The reaction products, linear alkyl benzene (LAB) and alkyl diphenyl ether are the intermediate of linear alkyl benzyl sulfonate and alkyl diphenyl oxide sulfonate production. After sulfonation and neutralization, two kinds of good surface active agents (SAA) are synthesized, the 2, 3-LAB isomers can be biodegraded and have excellent washing power. It is the base of modern synthesis detergent industry. The traditional catalysts application to the alkylation reactions are sulfuric acid, hydrofluoric acid and aluminum chloride which are out of time of environmental protection for their toxicity and corrosion, and it is hard to separate catalysts from the products. Green chemistry are the way of sustainable development of chemical industry in the future. Many kinds of solid acidic catalytic materials, including zeolites, molecular sieves, solid super strong acid, polyoxometalates, ionic liquids and organic solid acids, etc were studied for the alkylation reactions. The major disadvantages of solid acid catalysts in nowadays research efforts are their low selectivity, short life time and hard reaction conditions.In this works, three types of catalytic materials were studied; they were SO42-/ZrO2 solid super strong acid, ionic liquids and supported polyoxometalates. Design, preparation and characterization of these catalysts and their application in reactions of aromatic compounds alkylation with long chain olefin were the object matter. The catalysts synthesis conditions were researched and these materials were characterized by FT-IR, TG-DTA, BET, TEM, Powder XRD NH3-FTIR and NH3-TPD. The reaction parameters, such as reaction temperature, pressure, volume of catalyst in use and mole ratio of reactants were investigated. Thereinafter the procedures and the conclusions were listed.1. In the process of SO42-/ZrO2 solid super strong acid synthesis, the pH value of precipitation, the concentration of H2SO4 and the calcine temperature and time determined the catalysts' performance. The ZrCl4 should be precipitated in the range of pH 9-10, after the Zr(OH)4 were treated in 0.1-0.5mol L-1 H2SO4 solutions for 3-6 hours, they were calcined in 823-923K for 3-6 hours. Application in benzene alkylation with 1-dodecene, the conversion was 100%,the linearity of products was 100%, and the selectivity of 2-isomer was about 40%. The catalyst can be reused 5times. In the reaction of diphenyl ether alkylation with 1-dodecene, reaction conditions: DPE : 1-dodecene = 5, 343K, normal pressure, the conversion was above 67% and the selectivity of mono-alkyl diphenyl ether was 100%after 2 hours.2. Among different kinds of ionic liquids synthesized in this work, the AlCl3 type of ionic liquid show the highest catalytic activity when AlCl3 : cations = 2. The reaction of benzene alkylation with 1-dodecene can be completed in less than 1 min catalyzed by AlCl3 IL, room temperature, normal pressure, benzene '. 1-dodecene = 10, the selectivity of 2 and 3 isomers was above 60%. The conversion of DPE alkylation with 1-dodecene was 84% after 2 hours at 323K, and the selectivity of mono alkyl diphenyl ether was 100%.3. As a new kind of mesoporous molecular sieves, SBA-15 shows the great characters of good supporter with thick wall, high hydrothermal stability, large specific surface. Preparation of PW/SBA-15 by a new vacuum method through supported tungstophosphoric acid (PW) on SBA-15, the catalyst has high catalytic performance in alkylation reactions. Reaction conditions: benzene : 1-dodecene = 10, 351K, normal pressure, 30min. The conversion of benzene alkylation with 1-dodecene was 100%, linearity wasl00%, the selectivity of 2-LAB nearly 40%, and the recycle times of catalyst reuse was 9. In reaction of DPE alkylation with 1-dodecene, the conversion was 100% after 2 hours, reaction temperature 343K, the mono alkyl DPE selectivity was 100%...
Keywords/Search Tags:Alkylation, Benzene, Diphenyl Ether, 1-Dodecene, SO42-/ZrO2, Solid Super Acid, AlCl3 ionic liquid, SBA-15, Polyoxometalates, PW, Support, Conversion, Selectivity, linearity
PDF Full Text Request
Related items