Reactions of cycloalkanones in the presence of platinum-metal catalysts and hydrogen

Nishimura, Shigeo; Itaya, Takashi; Shiota, Michio

doi:10.1039/c19670000422

Cited by 12 publications

(7 citation statements)

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“…The above‐mentioned results demonstrate that EEP can be successfully synthesized by reductive etherification of EL on Pd/C modified with various oxides, albeit with different activities and selectivities. The reductive etherification of carbonyl compounds generally undergoes a consecutive acetalization–hydrogenolysis pathway . For instance, acetals of cyclohexanone, octanal, and furfural have been observed in large amounts without exception in the early stage of their reductive etherification process.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Ethyl‐4‐ethoxy Pentanoate by Reductive Etherification of Ethyl Levulinate in Ethanol on Pd/SiO₂‐C Catalysts

et al. 2018

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The synthesis of biomass-derived ethers to be used as biofuels or biofuel additives has attracted much attention. Following the recently reported synthesis of etherified ester ethyl-4-ethoxy pentanoate (EEP) from γ-valerolactone (GVL) in ethanol catalyzed by H-beta zeolite, an alternative route to prepare EEP in high yield has been developed by reductive etherification of ethyl levulinate (EL) in ethanol at 140 °C under 0.5 MPa H with a silica-modified Pd/C catalyst. The ether production likely follows a tandem acetalization-hydrogenolysis process with ethyl-4,4-diethoxy pentanoate (EDEP) as the intermediate. The acetalization step can be favored by introducing acidic materials, such as SiO -carbon or beta zeolite, as a cocatalyst. The combination of the Pd/SiO -C and beta zeolite mixture leads to 100 % EL conversion and 93 % EEP selectivity under optimized reaction conditions. For the first time, the standard molar combustion enthalpy of as-prepared EEP is measured by using a static oxygen bomb, and the value of which is determined to be about -5658 kJ mol , which is much larger than that of GVL (-2650 kJ mol ).

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Section: Resultsmentioning

confidence: 99%

Synthesis of Ethyl‐4‐ethoxy Pentanoate by Reductive Etherification of Ethyl Levulinate in Ethanol on Pd/SiO₂‐C Catalysts

et al. 2018

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“…Unfortunately, strong acidic conditions were required for acetalization steps. Four years later, the group of Nishimura reported the Pd(OH) 2 ‐catalyzed synthesis of ethers from cyclohexanones and a large‐excess of alcohol (Scheme 9B) [88] …”

Section: Reductive Etherification Of Alcohols or Surrogates With Aldehydes/ketonesmentioning

confidence: 99%

“…Four years later, the group of Nishimura reported the Pd(OH) 2 ‐catalyzed synthesis of ethers from cyclohexanones and a large‐excess of alcohol (Scheme 9 B). [88] …”

Section: Reductive Etherification Of Alcohols or Surrogates With Aldehydes/ketonesmentioning

confidence: 99%

Catalytic Reductive Alcohol Etherifications with Carbonyl‐Based Compounds or CO₂ and Related Transformations for the Synthesis of Ether Derivatives

et al. 2021

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Ether derivatives have myriad applications in several areas of chemical industry and academia. Hence, the development of more effective and sustainable protocols for their production is highly desired. Among the different methodologies reported for ether synthesis, catalytic reductive alcohol etherifications with carbonyl‐based moieties (aldehydes/ketones and carboxylic acid derivatives) have emerged in the last years as a potential tool. These processes constitute appealing routes for the selective production of both symmetrical and asymmetrical ethers (including O‐heterocycles) with an increased molecular complexity. Likewise, ester‐to‐ether catalytic reductions and hydrogenative alcohol etherifications with CO2 to dialkoxymethanes and other acetals, albeit in less extent, have undergone important advances, too. In this Review, an update of the recent progresses in the area of catalytic reductive alcohol etherifications using carbonyl‐based compounds and CO2 have been described with a special focus on organic synthetic applications and catalyst design. Complementarily, recent progress made in catalytic acetal/ketal‐to‐ether or ester‐to‐ether reductions and other related transformations have been also summarized.

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“…However, previous results for the conversion of 5-hydroxymethylfurfural (HMF) with Pd/C in alcoholic solution revealed that, in 1-propanol, 2-propoxy-5-hydroxymethylfuran was obtained in yields exceeding 85 % at 0.5 h. 70 Especially for Pd catalysts when ketones and aldehydes are subjected to hydrogenation using alcohols as solvents, the reaction may take place through a hemiacetal or acetal intermediate, which can subsequently be reduced to the corresponding ether. [70][71] The comparison of product distributions obtained from subjecting extracted lignins to Raney Ni under H2 pressure at 300°C indicates that there is an important interplay between acidity and temperature regarding the preservation of C3 side-chain of lignin's subunits in biomass deconstruction processes. 72 Notably, we recently reported that lignins obtained from the mechanocatalytic depolymerisation of H2SO4-impregnated lignocellulose [73][74] had the C3 side-chain preserved to an extent greater than that found for lignins from the organosolv process (with no added acid).…”

Section: Processes Occurring On Lignin Dissolved In the Liquormentioning

confidence: 99%

Chapter 5. Early-stage Conversion of Lignin over Hydrogenation Catalysts

Rinaldi¹

2018

Energy and Environment Series

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The deconstruction of lignocellulosic materials producing high-quality pulps together with lignin streams of low molecular weight (Mw) with controlled molecular diversity constitutes the overarching objective of Catalytic Upstream Biorefining (CUB) based on the Early-stage Catalytic Conversion of Lignin (ECCL). The CUB process based on ECCL or, simply, a "lignin first" approach builds on the lignin extraction with organic solvents in the presence of a hydrogenation catalyst under hydrogen pressure or employing an H-donor solvent (e.g. 2-propanol). Subjected to a hydrogenation catalyst, the lignin fragments undergo reductive processes, which decrease their reactivity and propensity to recondensation, directly upon their release from the lignocellulosic matrix. As a result, the isolated lignin fraction is a mixture of compounds of Mw 100-600 Da, with a high content of individual components. Herein, key concepts required for the rational deconstruction of lignocellulose based on ECCL are addressed. Notably, catalysis is now applied to the 'pulping process' itself, opening up new horizons for the realistic valorisation of lignin and full utilisation of lignocellulose via downstream catalytic processing of better-defined lignin streams.

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Reactions of cycloalkanones in the presence of platinum-metal catalysts and hydrogen

Cited by 12 publications

References 0 publications

Synthesis of Ethyl‐4‐ethoxy Pentanoate by Reductive Etherification of Ethyl Levulinate in Ethanol on Pd/SiO₂‐C Catalysts

Synthesis of Ethyl‐4‐ethoxy Pentanoate by Reductive Etherification of Ethyl Levulinate in Ethanol on Pd/SiO₂‐C Catalysts

Catalytic Reductive Alcohol Etherifications with Carbonyl‐Based Compounds or CO₂ and Related Transformations for the Synthesis of Ether Derivatives

Chapter 5. Early-stage Conversion of Lignin over Hydrogenation Catalysts

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Reactions of cycloalkanones in the presence of platinum-metal catalysts and hydrogen

Cited by 12 publications

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Synthesis of Ethyl‐4‐ethoxy Pentanoate by Reductive Etherification of Ethyl Levulinate in Ethanol on Pd/SiO2‐C Catalysts

Synthesis of Ethyl‐4‐ethoxy Pentanoate by Reductive Etherification of Ethyl Levulinate in Ethanol on Pd/SiO2‐C Catalysts

Catalytic Reductive Alcohol Etherifications with Carbonyl‐Based Compounds or CO2 and Related Transformations for the Synthesis of Ether Derivatives

Chapter 5. Early-stage Conversion of Lignin over Hydrogenation Catalysts

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Synthesis of Ethyl‐4‐ethoxy Pentanoate by Reductive Etherification of Ethyl Levulinate in Ethanol on Pd/SiO₂‐C Catalysts

Synthesis of Ethyl‐4‐ethoxy Pentanoate by Reductive Etherification of Ethyl Levulinate in Ethanol on Pd/SiO₂‐C Catalysts

Catalytic Reductive Alcohol Etherifications with Carbonyl‐Based Compounds or CO₂ and Related Transformations for the Synthesis of Ether Derivatives