Alkylation Of Naphthalene With Propylene Catalyzed By Immobilized Aluminum Chloride

Alkylation of naphthalene with propylene is the source reaction for the valuable chemical products of 2,6-DIPN which is a raw material for the production of advanced polyester fibers, films and plastics such as thermotropic liquid crystalline polymers. Traditionally, AICl3 is widely used in the chemical industry as an active catalyst, but it causes environmental problems, severe corrosion and difficult separation of reaction mixture. Thus, many efforts have been concentrated on solid acid catalysts, such as zeolite, for its environmentally friendly manufacture. However, the higher reaction tempreture (≥200℃) is necessary since its week acidity.In present work, AlCl3 immobilized on zeolite as support was firstly used to catalyze the alkylation of naphthalene with propylene. The aim is to develop a new catalyst possessing both high acitity of AICl3 and high selectivity of zeolite simultaneously. The main results are as follows:(1) AlCl3/Naβ, AlCl3/Si02, AlCl3/NaMCM-41, AlCl3/NaMCM-48, AlCl3/NaY and AlCl3/NaM catalysts were prepared by two-step vapor method, and these catalytic performances were evaluated in the alkylation of naphthalene with propylene. The results showed that AlCl3/Naβpossessed excellent catalytic performance. Under the optimal reaction conditions:normal pressure, reation temperature 65℃, catalyst 1.40mmol [-O-AICl2], cyclohexane 33ml, reaction time 5h, supporter's granular size smaller than 100 mesh, the naphthalene conversion of 76.33% and 2,6-DIPN/2,7-DIPN ratio of 1.02 could be obtained over AlCl3/Naβcatalyst.(2) The results of FT-IR spectra of chemically adsorbed pyridine indicated that Lewis as predominant acid species can be formed on the catalyst surface of AlC13 immobilized on NaB, SlO2 (coarse pores) and MCM-41, while the predominant acid species are Bronsted acid sites for AlCl3/NaY and AlCl3/NaM catalysts. From the N2 adsorption results, it can be seen that immobilization effect of AICl3 can decrease the surface area, pore volume and pore diameter of the catalysts. In the alkylation of naphthalene with propylene over the immobilized AlC13 catalysts, the pore diameter of the catalyst greatly influences the activity and 2,6-DIPN selectivity.(3) The result found herein is believed to be potentially important for production of 2,6-DIPN over immobilized AlC13 catalyst.