kinetics of selective hydrogenation of dimethyl maleate to dimethyl succinate in liquid phase

In this paper, the dimethyl succinate produced by hydrogenation of dimethyl maleate and the kinetics of liquid phase hydrogenation of dimethyl maleate to dimethyl succinate was primary studied over ruthenium catalyst in a methanol solution in the temperature range of 323 to 343 K. and hydrogen partial pressure from 0.4 to 1.2 MPa. The catalyst was found to be effective for the selective hydrogenation of dimethyl maleate and the dimethyl succinate was the only product. The reaction exhibited an apparent zero-order dependence on dimethyl maleate concentration at higher than ca. 0.26 mol/L, while a reaction order of 0.70 +/- 0.03 with respect to dimethyl maleate was obtained in the range of 0.015-0.180 mol/L. However, the reaction order with respect to hydrogen partial pressure was 0.82 +/- 0.05 in the tested dimethyl maleate concentration range. The activation energy had been found to be 58.926 +/- 2 kJ/mol. The obtained rate laws fitted well the experimmtal data.