Preparation of an active and regenerable catalyst for liquid-phase alkylation of toluene with 1-decene

• Catalytic performance of zeolite Y in the synthesis of alkyl aromatics.
• Structure collapse after oxidative regeneration of its unmodified H-form.
• Improvement of activity and stability towards regeneration.
• Hydrothermal treatment at 560 °C with subsequent ion-exchange with ammonium ions.
• Activity sustains after four cycles alkylation–regeneration.

Zeolite Y was tested as an alternative solid acid catalyst for the production of linear alkyl aromatics with the emphasis on its activity and stability towards regeneration. Liquid-phase alkylation of toluene with 1-decene at 100 °C was used as the model reaction. Deactivated catalyst samples were regenerated by the temperature programmed calcination (TPC) in air flow at 550 °C. The activity of the unmodified HY zeolite during alkylation was significant but decreased to a minimum after regeneration, as a result of a partial structure collapse during regeneration using TPC. To avoid the structure collapse hydrothermal stabilization of zeolite Y at 560, 670 and 780 °C was performed. Subsequent chemical dealumination using 0.5 M HCl or ion-exchange with the 2 M NH4NO3 solution, in order to improve the catalyst activity, were carried out. All the samples were then tested in alkylation. The main monitored parameters were the conversion of 1-decene, selectivity to 2-phenyldecane isomer and the amount of side-products. The sample stabilized at 560 °C and ion-exchanged subsequently showed the highest activity with the lowest amount of by-products. This sample was also regenerated and reused four times in the cycle alkylation–regeneration with no loss of structure or activity. In fact there was a slight activity increase of this sample after regeneration.

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