Hydrothermal synthesized Al-MCM-41 with different Si/Al ratios (30, 54, 78 and 107) were characterized by XRD, ICP-AES, BET, acidity measurement by pyridine adsorbed FT-IR spectroscopy, 29Si and 27Al MAS NMR techniques. The catalytic activity of these materials was tested in the vapour phase alkylation of tert-butylbenzene (TBB) with tert-butyl acetate (TBA) in the temperature range 200-400 °C. The products were found to be 1,4-di-tert-butylbenzene (1,4-DTBB), 1,3-di-tert-butylbenzene (1,3-DTBB), 4-acetyl-tert-butylbenzene (4A-TBB), 3-acetyl-tert-butylbenzene (3A-TBB), 2-acetyl-tert-butylbenzene (2A-TBB) and 2-acetyl-1,4-di-tert-butylbenzene (2A-1,4-DTBB). The selectivity towards 1,3-DTBB increased with increase in temperature, conversely the selectivity of 1,4-DTBB decreased. The selectivity to 4A-TBB, which is higher than that of other compounds, also increased with increase in temperature. The effect of temperature, flow rate and feed ratio was also studied over all the catalysts to arrive optimum conditions for higher conversion with product selectivity. The effect of time-on-stream was studied over all the catalysts and the results are discussed.
Bibliographical noteFunding Information:
This research was supported by Defence Research and Development Organization (DRDO), New Delhi, India. The authors are grateful to Department of Science and Technology (DST) and University Grants Commission (UGC), New Delhi for the funding to create instrumental facilities in the Department. One of the authors, S. Sudha is thankful to DRDO, New Delhi, for the award of a junior research fellowship (JRF).
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- tert-Butyl acetate