Mixed-Metal Oxide Catalyst for Liquid Phase Benzene Alkylation

M Alhassan,U Z Faruq,A Galadima

doi:10.34198/ejcs.2219.217234

Abstract

Development of cheaper, active and more ecofriendly heterogeneous acid catalyst is a challenge mitigating the petrochemical industries. CuO-MoO3/ZrO2 solid catalyst was prepared by impregnation using suitable precursor materials supported over zirconia. Upon calcination at 450°C for 2 h and activation (by soaking in 2M H2SO4 for 30 minutes), available techniques were employed for the characterization. The available oxides and minerals in the catalyst were revealed by the XRF and XRD profiles respectively. The catalyst crystallite size (131.6nm) was obtained using the Bragg’s equation from the latter. Thermal analysis showed three weight loss stages between (49.25-152.06°C), (152.06-559.47°C) and (559.47-752.0°C ) while presence of sulphate and zirconia oxides was revealed by the FTIR analysis due to appearance of absorption bands around 1225-980cm-1 and 700-600cm-1 respectively. The catalyst (1wt%) was tested for alkylation in a continuous stirred reactor at 80°C using variable (2:1, 4:1 and 10:1) benzene to 1-decene molar ratios. The effects of reaction time and molar ratios on the selectivity, conversion and yield were determined. The alkylation results showed that the catalyst is highly selective to 1-decylbenzene as low amount of side products was obtained. The product yield and conversion increased with reaction time and benzene /1-decene molar ratio while selectivity decreased with increase in benzene /1-decene molar ratio with time.

Highlights

The result of XRD analysis of the prepared catalyst presented in Table 1 indicated the presence of two principal minerals; Baddeleyite (42%) and Bonattite (58%)
The principal mineral components in the catalyst precursor are ZrO2 and hydrated copper sulphate (CuSO4.3H2O); constituting up to 42% of the solid catalyst; which agrees with Zhang et al [24] that up to 40wt % of the support can be employed
After calcination at 450°C, moisture due to physisorbed water is removed from the catalyst, the XRD analysis showed up to 12 moles of water

Summary

Introduction

Devassy and co-workers [6] reported similar results for zirconia supported 12-tungstophosphoric acid as a solid catalyst for the synthesis of linear alkyl benzenes. The thermogravimetric analysis (thermal evolution) result of the CuO-MoO3/ZrO2 catalyst (presented in Table 3 and Figure 5) showed that the first weight loss stage occurred within temperature range of 42.95°C to 152.06°C and accounted for 55% weight loss. Saxena et al [18] reported the highest conversion of 86.6% on alkylating benzene with zeolite-based catalyst and concluded that increase in reaction temperature could not enhance product conversion.

Results

Conclusion