Selectivity, hydrodynamics and solvent effects in a monolith cocurrent downflow contactor (CDC) reactor

The liquid phase hydrogenation of 2-butyne-1,4-diol (B) to cis-2-butene-1,4,-diol (C) was studied in a Monolith (CDC) Reactor. The effect of temperature, pressure, different solvents and gas and liquid feed rates on reaction rate and selectivity was determined. RTD measurements were made under different hydrodynamic conditions. The liquid flow was largely laminar with evidence of a stagnant wall film. Selectivity to C was observed to increase with hydrogen pressure and approaches 1 at high superficial gas velocities and conversion of B (>95%) as plug flow is approached. The flow regime was of influence on selectivity and kinetics, which was described by a dual site Langmuir-Hinshelwood mechanism.