Intrinsic Kinetics of 3-Hydroxypropanal Hydrogenation over Ni/SiO₂/Al₂O₃ Catalyst

Abstract

The hydrogenation of 3-hydroxypropanal (HPA) to 1,3-propanediol (PD) over Ni/SiO2/Al2O3 catalyst powder was carried out at 318−353 K and 2.60−5.15 MPa in a batchwise-operated stirred autoclave. A kinetic model which can well describe the reactions of this process was developed. The model parameters were estimated by the maximum likelihood function of the concentration of HPA and PD according to concentration−time profiles measured at different temperatures and pressures. To obtain high selectivity of PD the reaction temperature should be lower than 333 K.

Intraparticle diffusion in hydrogenation of 3‐hydroxypropanal

“…B and C), a heterogeneous catalytic main reaction and a side reaction occur simultaneously in the hydrogenation of HPA over Ni/Si0,/A1,03 catalyst pellets (Zhu, 1995;Zhu et al, 1996a). in the following way: the concentration Cj (i = HPA and PD) was at first expressed as a power-series function of the reaction time ( t ) C1,; = Zai,t' ( j = 0, .…”

“…where k, ( j = 1, 2, 3, -3, 4) are the intrinsic reaction-rate constants; K , ( Zhu, 1995;Zhu et al, 1996a. measurements of the concentration-time profiles, a good intrinsic kinetic model is very important for obtaining good values of the apparent effectiveness factors (for details, see Zhu et al, 1996a).…”

“…Such an effective kinetic model is not reliable for processing scale-up, as its parameters may vary with a change in catalyst particle size or reaction conditions. Instead, the method described by Zhu (1995) and Zhu et al (1996a), where the effective diffusion coefficients are used as a model parameter, should be applied to model the reaction processes with strong intraparticle diffusion.…”

Hydrogenolysis of 2-tosyloxy-1,3-propanediol into 1,3-propanediol over Raney Ni catalyst

“…Based on these proposed mechanism of 1,3-PD formation in glycerol hydrogenolysis, [19][20][21][22][23] the hydrogenolysis of TPD might occur as shown in Scheme 3. TPD undergoes a detosyloxylation to give 3-HPA and TsOH, the subsequent reaction of 3-HPA proceed via the following routes: (i) hydrogenation of 3-HPA to produce 1,3-PD, and (ii) dehydration of 3-HPA to form AO intermediate, and followed by the subsequent hydrogenation to produce 1-PrOH.…”

New diol processes: 1,3-propanediol and 1,4-butanediol

“…Increasing pressure has a positive effect on the selectivity by favouring the main reaction. However, this positive effect of an increasing hydrogen pressure is not sufficient to compensate the exponential negative effect of a rising reaction temperature on selectivity [13,16]. Accordingly, a suitable design of an industrial hydrogenation, including a high space time yield aims at highly active catalysts which allows conversions of almost 100% under mild reaction conditions (40-70 8C), so to achieve 1,3-propanediol with a selectivity close to 100% [13].…”