Continuous-flow processes for the catalytic partial hydrogenation reaction of alkynes

Abstract

The catalytic partial hydrogenation of substituted alkynes to alkenes is a process of high importance in the manufacture of several market chemicals. The present paper shortly reviews the heterogeneous catalytic systems engineered for this reaction under continuous flow and in the liquid phase. The main contributions appeared in the literature from 1997 up to August 2016 are discussed in terms of reactor design. A comparison with batch and industrial processes is provided whenever possible. 734

Active site isolation in bismuth-poisoned Pd/SiO2 catalysts for selective hydrogenation of furfural

“…Isolation of the active sites and electronic effects can be introduced into the catalyst by adding a second metal such as Pb, Au, Cu [60][61][62][63][64][65]. We have decided to investigate the effect of the addition of Bi because it preferentially adsorbs on the step and edge sites of Pd [35,36].…”

Hydrogenation reactions catalyzed by colloidal palladium nanoparticles under flow regime

“…[1][2][3][4][5][6][7][8] Among them, hydrogenation reactions catalyzed under heterogeneous regime have attracted the interest of several groups, generally grafting the catalysts on solid supports. [9][10][11][12][13] Pérez-Ramírez et al reported the semihydrogenation reaction of alkynes and the reduction of nitro-aromatic substrates using colloidal PtNPs and PdNPs capped by HHDMA (hexadecyl (2-hydroxyethyl) dimethylammonium dihydrogen phosphate) supported on carbon, titanium sulfide, and mesoporous graphite. [14][15][16] The substrate was pumped through the micro-reactor containing the catalyst bed, using an HPLC pump, together with hydrogen generated in situ by an electrolytic cell.…”

The effects of modes of hydrogen input and reactor configuration on reaction rate and H2 efficiency in the catalytic hydrogenation of alkynol to alkenol

“…Common reactors for multiphase catalytic reactions include stirred tank reactors (STR), packed/trickle bed reactors, bubble columns, and recently, microreactors where the catalyst is either stationary, eg in packed beds and microreactors, or mobile, eg in stirred tank reactors (STR). There are generally two modes of operation in terms of hydrogen supply, namely continuous gas flow, or gas‐on‐demand . In the former, hydrogen gas is pumped into the reactor continuously, which is generally termed as the open mode of operation.…”