Transesterification of dimethyl oxalate with phenol over TS-1 catalyst

The transesterification of dimethyl oxalate with phenol to produce methyphenyl oxalate and diphenyl oxalate was carried out in liquid phase using a heterogeneous catalyst. The evaluation results showed that TS-1 had better activity and excellent selectivity to target products compared with many conventional ester exchange catalysts tested. Two hours as the duration of the reaction was appropriate. Under the catalytic reaction conditions, framework IR and the reaction results jointly proved that the best calcination temperature was 823 K at which the amount of acid sites measured by IR of adsorbed pyridine reached a maximum. X-ray diffraction of TS-1 did not show much variation with changing calcination temperatures from 723 to 923 K. The characterization of the catalyst, by means of IR of adsorbed pyridine and NH3-TPD indicated that the desired catalytic activity of TS-1 could be ascribed to its weak Lewis acidity. Tin modified TS-1 showed a better performance in activity and selectivity. The conversion of dimethyl oxalate was improved up to 50.3% when Sn loading was 2, while the selectivity was above 99% over all Tin modified TS-1 molecular sieves.