Aqueous Phase Reforming of Industrially Relevant Sugar Alcohols with Different Chiralities

Abstract

The influence of substrate chirality was studied in the aqueous phase reforming (APR) over Pt/Al 2 O 3 in a continuous fixed-bed reactor at 225°C. Two epimeric sugar alcohols namely sorbitol and galactitol were used for performance comparison. For the very first time galactitol was used in the APR process. The reliability of the liquid-phase products analysis was considerably improved due to application of a spiking technique for qualitative analysis and subsequent peak fitting for quantification. A detailed analysis of the gas and liquid phases showed almost the same behavior of both polyols, apart from formation of several intermediate oxygenates. This implies that industrially relevant feedstock with different chirality can be efficiently processed in APR, since chirality of the initial substance does not affect the reaction rate and selectivity to the final products. However, the observed difference in the liquid phase composition should be considered, because the catalyst should be active in conversion of both polyols and oxygenates. Finally, possible reaction pathways were proposed and discussed from the thermodynamic point of view.

A review of catalytic aqueous-phase reforming of oxygenated hydrocarbons derived from biorefinery water fractions

“…Nonetheless, aqueousphase reforming of model compounds that represent real biorefinery water compositions or intermediate products typically formed in the APR process is recommendable to achieve a better understanding of the reaction mechanism [21]. Model compounds commonly applied in APR include oxygenated hydrocarbons such as glycerol [22], ethylene glycol, ethanol, methanol, acetic acid, acetaldehyde [23], acetol [24], butanol [25], cellulose [19], fructose, sucrose [26], furfural [27], glucose, sorbitol [5], galactitol [28], cyclic compounds [29], and xylitol [30].…”

Developments in the Atomistic Modelling of Catalytic Processes for the Production of Platform Chemicals from Biomass

“…For instance, glycerol decomposition on metals consists of 250 intermediates connected by roughly 2000 transition states, while for a typical C 6 the total number is more than two orders of magnitude larger . For such large molecules, the product distribution typically shows poor selectivity and this is one of the challenges of biomass conversion . Moreover, the identification of key transition states is not straightforward as many of them may have a similar degree of rate control for the overall product distribution .…”

“…[6] For such large molecules, the product distribution typically shows poor selectivity and this is one of the challenges of biomass conversion. [7] Moreover, the identification of key transition states is not straightforward as many of them may have a similar degree of rate control for the overall product distribution. [8] For these structures, small energy differences may lead to different product distributions to a large extent [9][10] and therefore, they should be computed accurately.…”

Cheese whey valorisation: Production of valuable gaseous and liquid chemicals from lactose by aqueous phase reforming

“…Kirilin et al [23] investigated the APR of xylitol and sorbitol using a Pt/Al 2 O 3 catalyst. Godina et al [24] analysed the APR of sorbitol and galactitol using a Pt/Al 2 O 3 catalyst in a continuous fixed-bed reactor at 225 °C.…”