Preparation of Au/C catalysts using microwave-assisted and ultrasonic-assisted methods for acetylene hydrochlorination

• Microwave-assisted and ultrasonic-assisted techniques are employed for synthesis of Au/C catalysts.
• Au/C prepared by ultrasonic-assisted technique shows higher activity and stability of hydrochlorination of acetylene.
• The optimum gold loading is 1 wt% Au/C, the excessive gold loading tends to form aggregation of active species.
• The different pretreatment procedures affect only the initial activity but almost identical in long-term activities.

In the present work, the catalytic performance of Au/C catalysts prepared by ultrasonic-assisted, microwave-assisted and incipient wetness impregnation techniques for the hydrochlorination of acetylene to vinyl chloride monomer (VCM) was studied. The catalyst prepared by the ultrasonic-assisted technique significantly exhibited enhanced acetylene conversion activity and selectivity to VCM over a period of 20 h of evaluation. The effect of gold loading on catalyst performance was determined, from which 1% Au was found to be the optimum loading compared to 0.5% and 2.0% loading. Importantly, the effect of different catalyst pretreatments (i.e. with and without H2/HCl and HCl purging prior to the reaction testing) on the catalytic performance was also identified. The use of different pretreatment procedures affects only the initial activity of catalyst, while the long-term activities of catalyst with different pretreatments are almost identical.

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