Study On Alkylation Of Benzene With Long-chain Olefins Over Immobilized AlCl₃ Catalyst

The catalyst of AlCl3 immobilized on Y -Al2O3 with meso- and macro-pore bimodal structure was prepared and evaluated in the alkylation of benzene with 1-dodecene in the suspension bed reactor. The effects of some parameters, including reaction temperature, reaction time and mole ratio of benzene to 1-dodecene etc., on the activity and stability of catalyst were studied, and the optimal reaction conditions were obtained.The immobilized AlCl3 catalyst was applied to the continuous alkylation reaction of benzene with 1-dodecene under the optimal reaction conditions. It was found that the catalyst exhibits higher activity, selectivety and stability, i.e. the life time of more than 1000h, the selectivity of mono- alkylbenzene of above 92% and the selectivity of 2-LAB of about 40%. The catalyst of immobilized AlCl3 on another kind of Y -Al2O3 support, which possesses meso-pore structure, was prepared and tested in the alkylation of benzene with commercial C10~C13 olefin/paraffin mixture. The activity and stability are similar to that of alkylation of benzene with 1-dodecene obtainted over immobilized AlCl3 on Y -Al2O3 with bimodal structure, and the selectivity of 2-LAB and mono-alkylbenzene is about 41 % and about 100%, respectively.The mechanism of deactivation of the immobilized AlCl3 catalyst during the alkylation reaction of benzene with 1 -dodecene was discussed. It is indicated that both the coverage of the bulkier molecules in active centre of catalyst and the loss of the active component in catalyst by the reaction of chloric species with water in feed contribute to the deactivation of catalyst.The catalyst, deactivated in lower reaction temperature, can be regenerated through the method of washing by solvent. However the catalyst deactivated in higher temperature, it is more difficult to be regenerated by this way because of the more bigger weight coke formed during the reaction process. To deal with the deactivated catalyst caused by the loss of the active component, the method of active species recovered by AlCl3 tetrachloride solution is adopted.