Mechanistic study of the ceria supported, re-catalyzed deoxydehydration of vicinal OH groups

Xi, Yongjie; Yang, Wenqiang; Ammal, Salai Cheettu; Lauterbach, Jochen A.; Pagán-Torres, Yomaira J.; Heyden, Andreas

doi:10.1039/c8cy01782d

Cited by 28 publications

(55 citation statements)

References 59 publications

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“…While previous studies focused on organometallic catalysts, the authors tested the process in the presence of perrhenate (ReO 4 À ). Xi et al [30] performed a detailed mechanistic study of a ceria-supported Re catalyst with Pd, which catalyzes the H 2 spillover as an efficient hydrogenation catalyst. [31] Among the studies on selective dehydroxylation, most focused on DODH of short-chain vicinal alcohols with homogeneous Re catalysts.…”

Section: Introductionmentioning

confidence: 99%

H₂‐Free Re‐Based Catalytic Dehydroxylation of Aldaric Acid to Muconic and Adipic Acid Esters

et al. 2020

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As one of the most demanded dicarboxylic acids, adipic acid can be directly produced from renewable sources. Hexoses from (hemi)cellulose are oxidized to aldaric acids and subsequently catalytically dehydroxylated. Hitherto performed homogeneously, we present the first heterogeneous catalytic process for converting an aldaric acid into muconic and adipic acid. The contribution of leached Re from the solid prereduced catalyst was also investigated with hot-filtration test and found to be inactive for dehydroxylation. Corrosive or hazardous (HBr/H 2) reagents are avoided and simple alcohols and solid Re/C catalysts in an inert atmosphere are used. At 120 8C, the carboxylic groups are protected by esterification, which prevents lactonization in the absence of water or acidic sites. Dehydroxylation and partial hydrogenation yield monohexenoates (93 %). For complete hydrogenation to adipate, a 16 % higher activation barrier necessitates higher temperatures.

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Section: Introductionmentioning

confidence: 99%

H₂‐Free Re‐Based Catalytic Dehydroxylation of Aldaric Acid to Muconic and Adipic Acid Esters

et al. 2020

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“…ReO x ‐Pd/CeO 2 catalyzed the DODH and subsequent hydrogenation of C=C bonds, such as erythritol to 1,2‐ and 1,4‐butanediols (1,2‐ and 1,4‐BuD), methylglycosides with cis ‐OH groups to the corresponding dideoxy products, and so on . Au or Pd promoters have the function of activating H 2 , and the activated hydrogen can move on the CeO 2 surface to enable the reduction of Re species in the reaction . Although Pd is a more effective promoter for H 2 activation, Pd is also active for C=C hydrogenation and thus the product over ReO x ‐Pd/CeO 2 becomes saturated.…”

Section: Introductionmentioning

confidence: 99%

“…[24] Au or Pd promoters have the function of activating H 2 ,a nd the activated hydrogen can move on the CeO 2 surface to enablet he reduction of Re speciesi nt he reaction. [19][20][21][22][23][24]29] Although Pd is amore effective promoter for H 2 activation,P di sa lso active forC =Ch ydrogenation and thus the product over ReO x -Pd/CeO 2 becomes saturated. 1,4-Anhydroerythritol (1,4-AHERY), which can be easily obtained from erythritol by dehydration, is often used in the DODH reaction because of its high reactivity toward DODH [14, 15, 19-23, 30, 31] and its origin from biomass.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2019

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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.

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“…Admittedly, Re speciation is truly complex in solid catalysts; the simultaneous presence of various Re species and their relatively facile interconversion in the presence of reductants and organic molecules makes it difficult to unequivocally determine the most relevant state of the Re species, especially under reaction conditions. A most recent theoretical work even found that the DODH activity on ReO x /CeO 2 (111) could be improved if a Re VII species (with higher activity than the Re VI species) could be stabilized (with the help of Pd in close proximity) under reaction conditions . Currently, it is perhaps only safe to conclude that more than one Re species may be responsible for the catalytic activity and some Re species is more of a promoter instead of serving a direct catalytic role.…”

Section: Deoxygenation Of Small Diols and Polyolsmentioning

confidence: 99%

Valorization of Biomass‐derived Small Oxygenates: Kinetics, Mechanisms and Site Requirements of H₂‐involved Hydrogenation and Deoxygenation Pathways over Heterogeneous Catalysts

Shi

2019

ChemCatChem

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Hydrodeoxygenation (HDO) is a key step in upgrading of biomass‐derived feedstocks to fuels and valuable chemicals. In this review, I select to discuss the current understanding of heterogeneous HDO catalysis of representative small oxygenates that are present in the bio‐crude obtained from thermochemical conversions of biomass raw materials, as the efficient valorization of these presently underutilized carbon sources would significantly improve carbon recovery and the overall process techno‐economics, in addition to facilitating downstream processing in some cases. A primary focus is laid on the kinetics, mechanisms and active site requirements of molecular H2‐involved hydrogenation and deoxygenation reactions of small aliphatic oxygenates. More often than not, surprising contrasts are found between gas‐solid and polar liquid‐solid interfaces and hint toward substantial restructuring and modifications of the catalytic surfaces and chemistries in polar liquids, particularly induced by protic molecules (the most abundant being water). Knowledge gaps, uncharted territories and associated challenges for the interrogations of these fundamental aspects are also discussed in this review.

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Mechanistic study of the ceria supported, re-catalyzed deoxydehydration of vicinal OH groups

Abstract: Deoxydehydration (DODH) is an emerging biomass deoxygenation process whereby vicinal OH groups are removed.

Cited by 28 publications

References 59 publications

H₂‐Free Re‐Based Catalytic Dehydroxylation of Aldaric Acid to Muconic and Adipic Acid Esters

H₂‐Free Re‐Based Catalytic Dehydroxylation of Aldaric Acid to Muconic and Adipic Acid Esters

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

Valorization of Biomass‐derived Small Oxygenates: Kinetics, Mechanisms and Site Requirements of H₂‐involved Hydrogenation and Deoxygenation Pathways over Heterogeneous Catalysts

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Mechanistic study of the ceria supported, re-catalyzed deoxydehydration of vicinal OH groups

Abstract: Deoxydehydration (DODH) is an emerging biomass deoxygenation process whereby vicinal OH groups are removed.

Cited by 28 publications

References 59 publications

H2‐Free Re‐Based Catalytic Dehydroxylation of Aldaric Acid to Muconic and Adipic Acid Esters

H2‐Free Re‐Based Catalytic Dehydroxylation of Aldaric Acid to Muconic and Adipic Acid Esters

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

Valorization of Biomass‐derived Small Oxygenates: Kinetics, Mechanisms and Site Requirements of H2‐involved Hydrogenation and Deoxygenation Pathways over Heterogeneous Catalysts

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H₂‐Free Re‐Based Catalytic Dehydroxylation of Aldaric Acid to Muconic and Adipic Acid Esters

H₂‐Free Re‐Based Catalytic Dehydroxylation of Aldaric Acid to Muconic and Adipic Acid Esters

Valorization of Biomass‐derived Small Oxygenates: Kinetics, Mechanisms and Site Requirements of H₂‐involved Hydrogenation and Deoxygenation Pathways over Heterogeneous Catalysts