Internal Surface Coating of a Capillary Microreactor for the Selective Hydrogenation of 2-Methyl-3-Butyn-2-Ol Using a PdZn/TiO2 Catalyst. The Effect of the Catalyst's Activation Conditions on Its Catalytic Properties

Finely divided polymer-stabilized PdZn bimetallic nanoclusters are prepared by the polyol method. TiO2 matrix-impregnated nanoclusters coated on the inner surface of a capillary microreactor are used as catalysts for the selective hydrogenation of 2-methyl-3-butyn-2-ol. The effect of the activation conditions (duration, temperature, and gas medium composition) on the physicochemical and catalytic properties of the coatings is studied. It is shown that their catalytic activities decrease and the reaction's selectivity increases with an increase in the reaction time and the time of hydrogen reduction at 573 K. The highest selectivity (96.5% at a conversion rate of 99%) is reached on the coatings reduced with hydrogen for 6 h. The coatings remain highly active and stable for 1 month in the continuous flow mode of the reaction. Kinetic simulation showed that a high selectivity level is ensured by a decrease in the rate constants of hydrogenation of 2-methyl-3-buten-2-ol and the ratio of the alkene/alkyne adsorption constants after reductive treatment.