solid acid catalyst and γ-butyrolactone benzene gas-solid phase synthesis of α-tetralone reaction

Title: solid acid catalyst and γ-butyrolactone benzene gas-solid phase synthesis of α-tetralone reaction Author: Wang deposited Degree-granting unit: Zhejiang University Keywords: FC reaction;; microporous molecular sieve;; γ-butyrolactone;; α-tetralone;; gas-solid reaction;; fixed-bed reactor Summary: α-tetralone is an important synthetic intermediates that can be used antidepressant Sertraline, different contraceptive norethindrone - ethinyl estradiol tablets ether, pesticides carbaryl, synthetic plastic softener. The existing literature shows that the air oxidation of tetralin, and benzene and γ-butyrolactone in AlCl_3 the catalyst to generate α-tetralone, but the air oxidation of tetralin conversion rate is low, AlCl_3 catalyst corrosion of equipment, pollution of the rare earth magnets environment and difficult to re-use and other issues, the reaction requires further green. In recent years, molecular sieve in acid-catalyzed FC reaction has been more attention. Zeolite is an important solid acid, has a certain acidity, rules and larger pore surface area, in the petrochemical, fine chemicals widely used synthetic field. May be needed, but the nature of the molecular sieve was modified to change its acidity and pore structure. Zeolite has a high thermal stability, high temperature burn off carbon deposits by means regeneration, reducing industrial costs. This paper mainly studies of benzene in a fixed bed reactor and the reaction of γ-butyrolactone, physical and chemical properties of the catalyst characterization system were compared, and discussed the acid-catalyzed reactions under the conditions of the law, proposed a possible reaction mechanism of micro- . Main contents and results are as follows: 1 impregnation method using an equal volume of the load to the ZnCl_2 γ-Al_2O_3 and activated carbon surface, the heteropoly acid H_3PW_ (12) O_ (40) load to the 7-Al_2O_3 surface, the gas-solid fixed bed reactor evaluation reactivity of the catalyst, the results showed that: ① 33.3% ZNCl_2/γ-Al_2O_3 and 33.3% ZnCl_2 / C on the gas-phase benzene and the reaction γ-butyrolactone with high catalytic activity, but 33.3% H_3PW_ (12) O_ (40) / γ-Al_2O_3 The catalytic reaction can not. ② 33.3% ZnCl_2/Al_2O_3 reaction at different temperatures showed that in the 300-360 ℃ range, γ-butyrolactone conversion rate was negatively correlated with temperature relationship. α-tetralone selectivity and yield is very low, the product, in addition to C benzene, 2 - D acid and α-tetralone there are more than 30% outside the product of the reaction mechanism is very complex. (2) of acidic zeolite and γ-butyrolactone benzene gas-solid reaction has a significant catalytic effect of zeolite catalysts results are quite different, but the main product is the C benzene (including benzene, cumene and n-propyl) , 2 - D acid and α-tetralone. Which HZSM5 Zeolite generated tetralone with high selectivity and stability, provides a synthesis of α-tetralone new method. Discussed in detail the reaction conditions on conversion, yield or selectivity, and possible reaction mechanism was proposed; In addition, HZSM5 (Si / Al = 50) of the hydrothermal treatment, heat treatment, phosphate and rare earth modified modified also carried out a more detailed examination. Main The results are: ① HZSM5 zeolite catalytic gas-phase benzene and γ-butyrolactone response to silica-alumina ratio Si / Al = 50 the best response to the results, HZSM5 (Si / Al = 50) occurred during the reaction inactivation, high temperature leads to burning or O_2 air to carbon can be regenerated catalyst regeneration that has good repeatability. ② modified phosphoric acid, water, heat treatment, heat treatment, and rare earth modified zeolites and other methods can improve the catalytic activity, while the product selectivity is not greatly affected. Modified heat treatment and heat treatment with http://www.chinamagnets.biz/ water to get a high activity and stability. ③ benzene and γ-butyrolactone gas-solid reaction of the possible reaction mechanism is: γ-butyrolactone first ring-opening reaction of benzene with 4-phenyl butyric acid, 4 - phenyl butyric acid intramolecular acylation reaction, cyclization to generate α-tetralone. Benzene and γ-butyrolactone gas-solid reaction mechanism may be ER. Generated during the reaction of propylene and 2 - crotonic aggregation may occur, leading to inactivation of the main molecular sieve. 3 were used NH_3-TPD, BET, XRD, and O_2-TG and other methods of acidic zeolites and modified zeolite characterization, the results showed that: ① different SiO2/Al2O3 of HZSM5 zeolite, silica-alumina greater than the smaller amount of acid. ② rare earth elements modified, high-temperature calcination, hydrothermal treatment and acid modification and other methods can reduce the total amount of acid zeolites HZSM5 and strong acid sites and the number of weak acid, but does not affect the HZSM5 zeolite surface phase structure. ③ HZSM5 (Si / Al = 50) before and after reaction and regeneration in the surface phase structure has not changed, indicating that inactivation is mainly due to molecular sieve product coke or coke. Degree Year: 2010