Selective Hydrogenolysis of Erythritol over Ir−ReO_x/Rutile‐TiO₂ Catalyst

Abstract

Partial hydrogenolysis of erythritol, which can be produced at large scale by fermentation, to 1,4‐butanediol (1,4‐BuD) is investigated with Ir−ReOx/SiO2 and Ir−ReOx/rutile‐TiO2 catalysts. In addition to the higher conversion rate over Ir−ReOx/TiO2 than over Ir−ReOx/SiO2, which has been also reported for glycerol hydrogenolysis, Ir−ReOx/TiO2 showed higher selectivity to 1,4‐BuD than Ir−ReOx/SiO2, especially at low conversion levels, leading to high 1,4‐BuD productivity of 20 mmol1,4‐BuD gIr−1 h−1 at 373 K (36 % conversion, 33 % selectivity). The productivity based on the noble metal amount is higher than those reported previously, although the maximum yield of 1,4‐BuD (23 %) is not higher than the highest reported values. The reactions of various triols, diols and mono‐ols are tested and the selectivity and the reaction rates are compared between catalysts and between substrates. The Ir−ReOx/TiO2 catalyst showed about twofold higher activity than Ir−ReOx/SiO2 in hydrogenolysis of the C−OH bond at the 2‐ or 3‐positions in 1,2‐ and 1,3‐diols, respectively, whereas the hydrogenolysis of C−OH at the 1‐position is less promoted by the TiO2 support. Lowering the loading amount of Ir on TiO2 (from 4 wt % to 2 or 1 wt %) decreases the Ir‐based activity and 1,4‐BuD selectivity. Similarly, increasing the loading amount on SiO2 from 4 wt % to 20 wt % increases the Ir‐based activity and 1,4‐BuD selectivity, although they remain lower than those for TiO2‐supported catalyst with 4 wt % Ir. High metal loadings on the support seem to be important.

Deoxydehydration of Biomass‐Derived Polyols Over Silver‐Modified Ceria‐Supported Rhenium Catalyst with Molecular Hydrogen

“…In particular, 1,2-butanediol was obtained from erythritol selectively, which is different from step-by-step CÀ O hydrogenolysis systems. [44][45][46][47][48][49][50][51][52] The activity and turnover number (TON) of ReO x -Pd/CeO 2 were much higher than those of the homogeneous Re catalyst systems, which also supported the heterogeneous catalysis. [40] On the other hand, solid Re catalysts on other supports have been reported to have comparable activity to homogeneous catalysts, and the involvement of leached species in the catalysis cannot be excluded.…”

“…As a result, high selectivity to mono‐alcohols and diols can be obtained from sugar alcohols with odd and even numbers of carbon atoms, respectively. In particular, 1,2‐butanediol was obtained from erythritol selectively, which is different from step‐by‐step C−O hydrogenolysis systems [44–52] . The activity and turnover number (TON) of ReO x ‐Pd/CeO 2 were much higher than those of the homogeneous Re catalyst systems, which also supported the heterogeneous catalysis [40] .…”

Hydrodeoxygenation of potential platform chemicals derived from biomass to fuels and chemicals

“…220,221 Fig. 27 shows the conversion and selectivity as a function of reaction time for erythritol hydrogenolysis over Ir-ReO x /rutile TiO 2 (4 wt% Ir, Re/Ir = 0.25) at 353 K. 222 The reaction temperature (353 K) for the Ir-ReO x catalyst was clearly lower than that (453 K) for the Cu catalyst, which was due to the very high activity of Ir-ReO x catalysts for C-O hydrogenolysis of various polyfunctionalized compounds such as sugars, 223,224 sugar alcohols, 222,[225][226][227] and cyclic ones. 228 The selectivity of the primary products can be estimated from the data at a lower conversion level (i.e., shorter reaction time) (Fig.…”

“…The highest yield of 1,4-butanediol was 23%, which is far from satisfactory. 222 From the viewpoint of the yield of 1,3-propanediol in glycerol hydrogenolysis, Pt-WO x catalysts are superior to Ir-ReO x catalysts. 212,229 The applicability of Pt-WO x catalysts to erythritol hydrogenolysis should be mentioned.…”

Rhenium – A Tuneable Player in Tailored Hydrogenation Catalysis

“…After the inspiring report of Trivedi et al., [181] which demonstrated for the first time the activity enhancement promoted by the synergic effect of the addition of other metals in Re 2 O 7 , Re‐based catalysts have been intensively explored [45,134,182–187] . Neurock et al.…”