Selective dealumination of large pore Zeolite Beta for effective Brempty setnsted acid site utilization

P Samanta and M Ussama and G Shrivastav and MA Haider and KK Pant and M Kumar, JOURNAL OF CATALYSIS, 440, 115796 (2024).

DOI: 10.1016/j.jcat.2024.115796

Tuning of Al sites through spatial and geometric distribution is a novel pursuit for deterministic catalytic performance. To design an efficient Zeolite Beta for phenol alkylation with optimal physicochemical attributes, we conducted a systematic study with a series of dicarboxylic acids to selectively extract the framework and/or non- framework Aluminium. Herein, the post-synthetic treatment resulted in dealuminated catalysts of silicon-to- aluminum ratio similar to 15-53. Extensive Al and Si NMR studies glean the selective extraction of aluminum from the zeolitic framework along with recomposition in T sites. The potency study alludes to the convoluted role of pH, chelating ability, and/or site accessibility for complexation. The differentiated Al extraction results in the emergence of unique super-strong acid sites. The novelty of our approach was established using phenol alkylation with cyclohexanol wherein we observed the highest conversion and desired C-C alkylated product formation for the malonic acid-treated Zeolite Beta.

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