Solvent-free semihydrogenation of acetylene alcohols in a capillary reactor coated with a Pd–Bi/TiO 2 catalyst

Abstract

A solvent-free semihydrogenation of 2-methyl-3-butyn-2-ol (MBY) to 2-methyl-3-buten-2-ol was performed in a capillary reactor (10 m long, 0.53 mm i.d.) coated with a titania supported Pd-Bi catalyst.

Process Intensification of Alkynol Semihydrogenation in a Tube Reactor Coated with a Pd/ZnO Catalyst

“…In our previous works, we have demonstrated that the catalyst-coated tube reactors are very efficient in providing high selectivity towards intermediate hydrogenation products over the Bipoisoned Pd catalysts [28,36]. The selectivity in such reactors was demonstrated to be as high as in an ideal batch reactor with the same catalyst.…”

“…Hence, the maximum product selectivity obtained is determined only by the catalyst chemistry with no handicap being brought by the reactor [24,28]. However, the catalyst-coated tubes were demonstrated so far only at the milligram [38] to 10 g a day throughput levels [28,36], which are not suitable for industrial applications [35,39,40]. We have extrapolated the experimental performance of the tube reactors wall-coated with the Pd/ZnO catalyst and showed that a throughput of above 4 kg a day is feasible in a single 5 m long 1.5 mm ID reactor in the solvent-free MBY semihydrogenation [41].…”

“…The macroporous structure formed by such needle-shaped crystals of the coating is greatly beneficial for the internal mass transfer as it provides high diffusion coefficients when compared to microporous materials. that provides a simple hydrodynamics and excellent control of residence time due to the Taylor flow regime [28,[35][36][37].…”

“…The selectivity in such reactors was demonstrated to be as high as in an ideal batch reactor with the same catalyst. Hence, the maximum product selectivity obtained is determined only by the catalyst chemistry with no handicap being brought by the reactor [24,28]. However, the catalyst-coated tubes were demonstrated so far only at the milligram [38] to 10 g a day throughput levels [28,36], which are not suitable for industrial applications [35,39,40].…”

“…An alternative approach is the application of structured reactors; however, they demonstrate low heat removal rates and are often operated in a recycle mode requiring high energy input into the reactant pumping [32][33][34]. The high operational costs can be overcome using a single tubular reactor that provides a simple hydrodynamics and excellent control of residence time due to the Taylor flow regime [28,[35][36][37].…”