Fabrication of desilicated MTW zeolite and its application in catalytic cracking of n-heptane

• Desilicated MTW zeolite was fabricated under microwave irradiation.
• Mesoporous MTW produced by alkaline treatment was applied for n-heptane cracking.
• Maximum average conversion of 75.3% was achieved with long catalyst stability.
• Higher selectivity to olefins (63.51%) was maintained for a long reaction time.

Desilicated MTW zeolite was developed for long chain hydrocarbon cracking such as n-heptane cracking. The catalytic performance of desilicated ZSM-12 (MTW) zeolite was investigated for n-heptane cracking in a fixed bed reactor at 650 °C and atmospheric pressure. Average conversion of 75.3% was achieved with a stability of 240 min. Higher selectivity to olefins (63.51%) was observed over a mesoporous MTW catalyst (treated with 0.2 M sodium hydroxide for 10 min) with average propylene to ethylene ratio (P/E) of 0.73. Desilicated MTW zeolite was prepared by using alkaline treatment under microwave irradiation to obtain ZSM-12 with larger pore volume (mesopores), larger surface area and different strength of acid sites. Maximum mesopore volume was 0.53 cm3 g−1 with external surface area of 437 m2 g−1. This is a remarkable result for mesoporous MTW prepared by post-alkaline treatment.

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