Improved stability of catalytic coatings based on Zn-doped titania for selective hydrogenation of a triple bond in a microcapillary reactor

A series of mixed oxides Ti x Zn 1−x O 1+x was synthesized by the sol–gel method using Pluronic F127 as a template and employed as a matrix for the synthesis of PdZn catalytic coating in selective hydrogenation of 2-methyl-3-butyn-2-ol (MBY). The effect of Zn/Ti molar ratio on the porous and crystalline structure of the matrix was discussed. The PdZn catalytic coating based on Zn-doped titania demonstrated a higher selectivity compared to undoped titania and retained a high selectivity of 98% in a continuous reaction flow up to 168 h, which is due to the resistance of the PdZn alloy to decomposition under the reaction conditions. Holding in an oxidizing atmosphere were accompanied by a decrease in selectivity from 98 to 95%; the reaction parameters were restored in the reaction stream of a solution of MBY in methanol and hydrogen for 24 h.