Preparation of Highly Active Monometallic Rhenium Catalysts for Selective Synthesis of 1,4‐Butanediol from 1,4‐Anhydroerythritol

Abstract

1,4‐Butanediol can be produced from 1,4‐anhydroerythritol through the co‐catalysis of monometallic mixed catalysts (ReOx/CeO2+ReOx/C) in the one‐pot reduction with H2. The highest yield of 1,4‐butanediol was over 80 %, which is similar to the value obtained over ReOx–Au/CeO2+ReOx/C catalysts. Mixed catalysts of CeO2+ReOx/C showed almost the same performance, giving 89 % yield of 1,4‐butanediol. The reactivity trends of possible intermediates suggest that the reaction mechanism over ReOx/CeO2+ReOx/C is similar to that over ReOx–Au/CeO2+ReOx/C: deoxydehydration (DODH) of 1,4‐anhydroerythritol to 2,5‐dihydrofuran over ReOx species on the CeO2 support with the promotion of H2 activation by ReOx/C, isomerization of 2,5‐dihydrofuran to 2,3‐dihydrofuran catalyzed by ReOx on the C support, hydration of 2,3‐dihydrofuran catalyzed by C, and hydrogenation to 1,4‐butanediol catalyzed by ReOx/C. The reaction order of conversion of 1,4‐anhydroerythritol with respect to H2 pressure is almost zero and this indicates that the rate‐determining step is the formation of 2,5‐dihydrofuran from the coordinated substrate with reduced Re in the DODH step. The activity of ReOx/CeO2+ReOx/C is higher than that of ReOx–Au/CeO2+ReOx/C, which is probably related to the reducibility of ReOx/C and the mobility of the Re species between the supports. High‐valent Re species such as Re7+ on the CeO2 and C supports are mobile in the solvent; however, low‐valent Re species, including metallic Re species, have much lower mobility. Metallic Re and cationic low‐valent Re species with high reducibility and low mobility can be present on the carbon support as a trigger for H2 activation and promoter of the reduction of Re species on CeO2. The presence of noble metals such as Au can enhance the reducibility through the activation of H2 molecules on the noble metal and the formation of spilt‐over hydrogen over noble metal/CeO2, as indicated by H2 temperature‐programmed reduction. The higher reducibility of ReOx–Au/CeO2 lowers the DODH activity of ReOx–Au/CeO2+ReOx/C in comparison with ReOx/CeO2+ReOx/C by restricting the movement of Re species from C to CeO2.

Recent Advances in the Deoxydehydration of Vicinal Diols and Polyols

“…Differences in reactivity were observed for different Au loading methods; impregnation provided larger Au particles (≈12 nm) that were less able to activate H 2 activation compared with deposition‐precipitation which provided smaller particle sizes (≈3 nm) . A co‐catalytic monometallic system for the conversion of 1–4‐anhydroerythritol to 1,4‐butanediol was also reported and adopts a DODH/ isomerization/ hydration/ hydrogenation pathway (Scheme ) . ReO x /CeO 2 in combination with ReO x /C‐BP as catalysts provided 1,4‐butanediol in 89 % yield under an atmosphere of H 2 at 140 °C in dioxane.…”

Tungsten–zirconia-supported rhenium catalyst combined with a deoxydehydration catalyst for the one-pot synthesis of 1,4-butanediol from 1,4-anhydroerythritol

“…In the most recent research, we also found that the ReO x /CeO 2 catalyst without an Au promoter still could catalyze the DODH reaction in the presence of ReO x /C, enabling the reduction of 1,4-AHERY to 1,4-butanediol with the mixture of ReO x /CeO 2 and ReO x /C. 39 The Re species on carbon could activate H 2 like an Au promoter for the reduction of Re species on the CeO 2 surface which are the active sites in the conversion of 1,4-AHERY. Furthermore, CeO 2 without Re loading combined with ReO x /C even could convert 1,4-AHERY to 1,4-BuD, because the Re species on the carbon surface could move to CeO 2 surfaces to form ReO x /CeO 2 .…”

“…(10) As above, the optimized reaction conditions for 1,4-BuD production from 2,5-DHF were a temperature of 413 K and a H 2 pressure of 8 MPa, which were the same reaction conditions used in the reaction of 1,4-AHERY over the combination of ReO x -Au/CeO 2 (or ReO x /CeO 2 ) and ReO x /C catalysts as reported in our previous reports. 23,39 The optimized ReO x /WO 3 -ZrO 2 catalyst was applied to the reaction of 1,4-AHERY combined with the ReO x -Au/CeO 2 catalyst for DODH of 1,4-AHERY to 2,5-DHF under the standard reaction conditions. The time course of the reaction of 1,4-AHERY over the mixture of ReO x -Au/CeO 2 and ReO x / WO 3 -ZrO 2 is shown in Fig.…”

“…We were unable to reuse the mixed catalyst of ReO x -Au/CeO 2 + ReO x /C due to the deactivation after catalytic use, as well as the difficulty in regeneration because of the combustibility of the carbon support, 23,39 while ReO x -Au/CeO 2 for DODH can be totally regenerated by calcination without a change of catalyst structure including the Au particle size. 32 Therefore, the reusability of the ReO x /WO 3 -ZrO 2 catalyst combined with ReO x -Au/CeO 2 was the most important part in this study.…”

Hydro(deoxygenation) Reaction Network of Lignocellulosic Oxygenates

“…The sample composition was also found to be excellent for low‐pressure DODH of methyl glycosides, in which protection of the stereostructure with high selectivity without protection of OH groups to the corresponding unsaturated sugar revealed this to be a powerful tool for biomass utilization . 1,4‐Butanediol can be derived from 1,4‐anhydroerythritol by using the monometallic mixed catalyst ReO x /CeO 2 +ReO x /C, which involves a rate‐determining step of forming 2,5‐dihydrofuran with reduced Re in the DODH step, in which the reducibility and mobility of Re species between supports plays a significant role …”