分子篩催化苯甲醚的Friedel-Crafts反應(yīng)的研究.pdf

1、河北大學(xué)碩士學(xué)位論文分子篩催化苯甲醚的Friedel-Crafts反應(yīng)的研究姓名：竇海洋申請(qǐng)學(xué)位級(jí)別：碩士專業(yè)：應(yīng)用化學(xué)指導(dǎo)教師：白國(guó)義20100501Abstract IIAbstract Friedel-Crafts reaction is one of the most important methods for the production of aromatic compounds. Friedel-Crafts reacti

2、on is carried out commercially using Lewis acids, such as AlCl3, or Brönsted acids, typically H2SO4 or HF. However, these traditional catalysts have limitations such as environmental pollution hazards arising from t

3、he disposal of potential toxic wastes, reactor corrosion and difficulty in handling. Furthermore, the catalyst amount to be employed is more than the stoichiometric quantity required. In recent years, zeolite is being mo

4、re and more regarded as an environmentally friendly catalyst instead of traditional catalysts for Friedel-Crafts reaction. p-Methoxyacetophenone was synthesized by Friedel-Crafts acylation of anisole and acetic anhydrid

5、e over Cr-doped Hβ zeolite in this paper. The conversion of acetic anhydride and selectivity to p-methoxyacetophenone are both over 99.0% under the optimized reaction conditions. This is attributed to the increase of wea

6、k and moderately-strong acid sites, caused by the Cr addition. The formation of carbonaceous materials and their coating of the acid sites are believed to be the reasons for the deactivation of the reused Cr-doped Hβ zeo

7、lite, as indicated by BET, SEM, XPS and NH3-TPD measurement results. The catalyst activity can be recovered effectively by a subsequent calcination. Meanwhile, the effect of phosphoric acid modiffition on catalytic perfo

8、rmance of Hβ zeolite for acylation of anisole is presented. Effect of phosphoric acid modification was studied based on XRD and NH3-TPD characterization. The influence of the reaction temperature, the catalyst amount and

9、 the reaction time on the acetic anhydride conversion were investigated and optimized. The conversion of acetic anhydride and the selectivity to p-methoxyacetophenone are both higher than 99.0% in four runs catalyzed by

10、the recycled catalysts under the optimum reaction conditions, while the reaction temperature is 120 ℃, the catalyst amount is 2.0 g and the reaction time is 2 h. On the other hand, oxalic acid modified Hβ (OA-Hβ) zeolite

11、 is found to have better catalytic performance than Hβ zeolite in the Friedel-Crafts hydroxyalkylation of anisole with chloral. This is attributed to the increase of weak and moderately-strong acid sites, caused by oxali

12、c acid modification. Furthermore, it is believed that the carbonaceous deposits on the acid sites and the blockage of the pores, together with poisoning by chlorinated materials, are responsible for the deactivation of O