Efficient Hydrogenation of Xylose and Hemicellulosic Hydrolysate to Xylitol over Ni-Re Bimetallic Nanoparticle Catalyst

Abstract

A disadvantage of the commercial Raney Ni is that the Ni active sites are prone to leaching and deactivation in the hydrogenation of xylose to xylitol. To explore a more stable and robust catalyst, activated carbon (AC) supported Ni-Re bimetallic catalysts (Ni-Re/AC) were synthesized and used to hydrogenate xylose and hemicellulosic hydrolysate into xylitol under mild reaction conditions. In contrast to the monometallic Ni/AC catalyst, bimetallic Ni-Re/AC exhibited better catalytic performances in the hydrogenation of xylose to xylitol. A high xylitol yield up to 98% was achieved over Ni-Re/AC (n Ni :n Re = 1:1) at 140 • C for 1 h. In addition, these bimetallic catalysts also had superior hydrogenation performance in the conversion of the hydrolysate derived from the hydrolysis reaction of the hemicellulose of Camellia oleifera shell. The characterization results showed that the addition of Re led to the formation of Ni-Re alloy and improved the dispersion of Ni active sites. The recycled experimental results revealed that the monometallic Ni and the bimetallic Ni-Re catalysts tended to deactivate, but the introduction of Re was able to remarkably improve the catalyst's stability and reduce the Ni leaching during the hydrogenation reaction.

Selective aqueous phase hydrogenation of xylose to xylitol over SiO2-supported Ni and Ni-Fe catalysts: Benefits of promotion by Fe

“…The Ni100/SiO2 and Ni62Fe38/SiO2 catalysts thus showed a high catalytic activity across the range of xylose concentration tested here (3.7-11.0 wt.%), at a temperature of 80 °C only, compared with other systems reported in the literature for which a lower xylose concentration (0.5-4.7 wt.%) and a higher reaction temperature (140-150 °C) were generally used. [31,34,35] Compared with the Ni catalyst, the specificity of bimetallic Ni62Fe38/SiO2 seems to be related to a larger apparent rate constant (competing though with a larger adsorption constant of xylose on the active sites) and to a higher stability. Commenting on the origin of the differences between the apparent rate constants is difficult, as in this model, rate constants implicitly include contributions from the true kinetic constant, from adsorption constants, and from the number of active sites, all of which can differ between the two catalysts.…”

“…[22,29,30] On the other hand, the addition of a metallic promoter has been shown to enhance the catalytic performances of Ni in the hydro-conversion of other saccharides, such as glucose and cellulose. [28,[31][32][33][34][35] Gallezot et al studied the addition of promoters to Raney ® Ni, such as Cr, Mo, Sn and Fe, in the aqueous phase hydrogenation of glucose (40 wt.% in a 10% solution of acetic acid) at 130 °C under 50 bar H2. The addition of Mo and Cr increased the rate of glucose hydrogenation up to six times.…”

“…After 1 h, Ni/AC yielded 62.7% of xylitol at 70% conversion, and the addition of Re increased the activity, producing 98% of xylitol at 99% conversion. [31] Chieffi et al have reported that xylose (0.1 mol.L -1 in water) was quantitatively hydrogenated into xylitol at 150 °C under 50 bar H2, in a continuous process based on a 27wt.% Ni-20 wt.% Fe catalyst supported on 4 carbon, but no kinetic study was provided. [34] Indeed, compared with rhenium, Fe appears as a promising promoter of Ni due to its abundance and low cost.…”

Efficient Synthesis of Sugar Alcohols over a Synergistic and Sustainable Catalyst

“…In recent years, several studies applied non‐noble metal catalysts for hydrogenation of lignocellulosic‐derived sugars, but most studies only yield a single xylitol or sorbitol, and did not obtain or study high value‐added arabitol or mannitol. [ 19,24‐26 ] The following side reactions are one of the main reasons for the low yield of sugar alcohols (especially arabitol) in the reported literatures. It is well known that sugar alcohols can be produced by hydrogenation or isomerization/hydrogenation of lignocellulosic‐derived sugars.…”

Efficient D‐Xylose Hydrogenation to D‐Xylitol over a Hydrotalcite‐Supported Nickel Phosphide Nanoparticle Catalyst

“…[3,4] The hydrogenation of D-xylose is a reliable method for the production of D-xylitol, because D-xylose can be obtained from the hydrolysis of beechwood hemicelluloses, which are one of the cheapest and most earth-abundant carbon resources. To date, this reaction has been performed over nonprecious metal-based heterogeneous catalysts, such as Ni [5][6][7][8][9] and Co. [10] In this context, sponge Ni catalysts (Raney Ni catalysts) are widely used as industrial catalysts. However, sponge Ni catalysts suffer from low activities, requiring relatively high H 2 pressures of 40-70 bar to give successful transformations.…”