Catalytic oxidative C–C bond cleavage route of levulinic acid and methyl levulinate

RSC Advances ◽  
2016 ◽  
Vol 6 (76) ◽  
pp. 72744-72749 ◽  
Author(s):  
Fei Xia ◽  
Zhongtian Du ◽  
Junxia Liu ◽  
Yangyang Ma ◽  
Jie Xu
Keyword(s):  
Levulinic Acid ◽  
Bond Cleavage ◽  
Oxidative Cleavage ◽  
Methyl Levulinate ◽  
The Difference

The difference in the catalytic oxidative cleavage route between levulinic acid and methyl levulinate was intensively investigated.

scholarly journals Chemoselective hydrogenation of arenes by PVP supported Rh nanoparticles

2016 ◽  
Vol 45 (48) ◽  
pp. 19368-19373 ◽  
Author(s):  
Mahmoud Ibrahim ◽  
Raju Poreddy ◽  
Karine Philippot ◽  
Anders Riisager ◽  
Eduardo J. Garcia-Suarez
Keyword(s):  
Levulinic Acid ◽  
Organometallic Complex ◽  
Methyl Levulinate ◽  
Chemoselective Hydrogenation

Polyvinylpyrrolidone-stabilized Rh nanoparticles (RhNPs/PVP) of ca. 2.2 nm in size were prepared by the hydrogenation of the organometallic complex [Rh(η3-C3H5)3] in the presence of PVP and evaluated as a catalyst in the hydrogenation of a series of arene substrates as well as levulinic acid and methyl levulinate.

scholarly journals The difference in stability between 5′R and 5′S diastereomers of 5′,8-cyclopurine-2′-deoxynucleosides. DFT study in gaseous and aqueous phase

2010 ◽  
Vol 8 (1) ◽  
pp. 134-141 ◽  
Author(s):  
Boleslaw Karwowski
Keyword(s):  
Density Functional ◽  
Bond Cleavage ◽  
Basis Set ◽  
Small Range ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Formic Acid Hydrolysis ◽  
The Difference ◽  
The Stability ◽  
First Time

AbstractOxidatively generated damage to DNA frequently appears in the human genome as an effect of aerobic metabolism or as the result of exposure to exogenous oxidizing agents. Due to these facts it has been decided to calculate the stability of 5′,8-cyclo-2′-deoxyadenosine/guanosine (cdA, cdG) in their 5′R and 5′S diastereomeric forms. For all points of quantum mechanics studies presented, the density functional theory (DFT) with B3LYP parameters on 6-311++G** basis set level was used. The calculations showed a significant negative enthalpy for glycosidic bond cleavage reaction for cationic forms and slightly negative for neutral ones. The preliminary study of the discussed process has shown the nature of stepwise nucleophilic substitution DN*AD type mechanism. Surprisingly, the different values in free energy, between short-lived oxacarbenium ion intermediates, have been found to lie over a relatively small range, around 1 and 2.8 kcal mol−1. For anions, the decomposition enthalpies were found as positive in aqueous phases. These theoretical results are supported by the formic acid hydrolysis experiments of both diastereomers of cdA, for the first time. (5′S)cdA exhibited higher stability than (5′R)cdA.

scholarly journals A Theoretical Investigation on the Hydrodesulfurization Mechanism of Hydrogenated Thiophene Over Cu-mo Modified Fau Zeolite

2021 ◽  
Author(s):  
Suyang Li ◽  
Yingxin Sun ◽  
Sheng Han ◽  
Qianggen Li
Keyword(s):  
Ring Opening ◽  
Hydrogen Transfer ◽  
Bond Cleavage ◽  
Van Der Waals ◽  
Van Der Waals Interactions ◽  
Chemical Bonds ◽  
Catalytic Center ◽  
Fau Zeolite ◽  
Thiophene Derivatives ◽  
The Difference

Abstract We have carried out a two-layer our own n-layered integrated molecular orbital and molecular mechanics (ONIOM) study on the hydrodesulfurization (HDS) mechanism of three hydrogenated thiophene derivatives over Cu-Mo modified FAU zeolite. The thiophene is hydrogenated relatively easily to 2,3-dihydrothiophene (2,3-DHT), 2,5-dihydrothiophene (2,5-DHT) and tetrahydrothiophene (THT) due to low free energy barriers. Hydrogenolysis desulfurization (HYD) and direct desulfurization (DDS) are discussed. Ring-opening, hydrogen transfer and C−S bond cleavage steps of thiophene derivatives are involved in the HYD process. The rate-determining steps are the hydrogen transfer step for 2,5-DHT and C−S bond cracking step for 2,3-DHT and THT. The concerted DDS pathway is probably more favorable than the HYD pathway in the desulfurization of 2,5-DHT. The hydrogenation of thiophene to 2,5-DHT, 2,3-DHT and THT and their HDS process are entropy-decreased; the formation of sulfur vacancy is entropy-increased. The difference charge density (DCD) analysis reveals that for the ring-opening process, the electrons are migrated from the organic chain to the Cu-Mo catalytic center. The reduced density gradient (RDG) plots indicate that both a steric hindrance and a weak van der Waals attractive interaction exist between organic fragment and catalytic center for all transition states (TSs). The localized orbital locator (LOL) maps for all TSs suggest that there are strong covalent interactions between the atoms in the forming chemical bonds and weak van der Waals interactions between the atoms in the breaking chemical bonds.

Copper-catalyzed aerobic oxidative cleavage of C–C bonds in epoxides leading to aryl nitriles and aryl aldehydes

2015 ◽  
Vol 51 (30) ◽  
pp. 6572-6575 ◽  
Author(s):  
Lijun Gu ◽  
Cheng Jin
Keyword(s):  
Bond Cleavage ◽  
Oxidative Cleavage ◽  
Single Bond ◽  
Aryl Aldehydes ◽  
Aryl Nitriles

Novel copper-catalyzed aerobic synthesis of aryl nitriles and aldehydes from epoxides via C–C single bond cleavage has been discovered.

Asymmetric synthesis of 3-aryl-substituted 2,3-dihydro-1H-isoindol-1-ones

2001 ◽  
Vol 79 (11) ◽  
pp. 1528-1535 ◽  
Author(s):  
Dieter Enders ◽  
Volker Braig ◽  
Gerhard Raabe
Keyword(s):  
Asymmetric Synthesis ◽  
Bond Cleavage ◽  
Oxidative Cleavage ◽  
Ring Closure

The first asymmetric synthesis of 3-aryl substituted 2,3-dihydro-1H-isoindol-1-ones via a tandem nucleophilic 1,2-addition ring closure procedure from SAMP and (or) RAMP hydrazones and subsequent oxidative cleavage of the auxiliary is reported.Key words: isoindolinones, asymmetric synthesis, hydrazones, 1,2-addition, N—N bond cleavage.

ESTERIFICATION OF RENEWABLE LEVULINIC ACID TO LEVULINATE ESTERS USING AMBERLYST-15 AS A SOLID ACID CATALYST

2016 ◽  
Vol 79 (1) ◽  
Author(s):  
Nur Aainaa Syahirah Ramli ◽  
Nur Hidayah Zaharudin ◽  
Nor Aishah Saidina Amin
Keyword(s):  
Levulinic Acid ◽  
Solid Acid ◽  
Solid Acid Catalyst ◽  
Acid Catalyst ◽  
Molar Ratio ◽  
Catalyst Loading ◽  
Process Conditions ◽  
Amberlyst 15 ◽  
Methyl Levulinate ◽  
Exchange Resins

Levulinic acid (LA) is a versatile biomass-derived building block as it can be used for the synthesis of organic chemicals as alternative to the depleting fossil fuel resources. Levulinate esters, obtained from catalytic esterification of LA with alcohol, can be used in many applications such as fragrance and fuel additives. In this study, ion-exchange resins Amberlyst-15 was employed as solid acid catalyst for esterification of LA with methanol for methyl levulinate (ML) production. The effect of reaction time, catalyst loading, and molar ratio of LA to methanol, was investigated on LA esterification to ML at the reflux condition. The optimum ML yield of 82% was obtained from reaction conducted at reflux temperature for 5h, using 30% of Amberlyst-15 loading, and 1:20 of LA to methanol molar ratio. The reusability of Amberlyst-15 for ML production was examined for five successive reactions. In addition, Amberlyst-15 catalyst, employed in the esterification of LA with ethanol and 1-butanol for ethyl levulinate (EL) and butyl levulinate (BL), respectively, registered good performance. Yields of 71% and 55% have been obtained for EL and BL, respectively. Amberlyst-15 is a promising solid acid catalyst for production of biomass derived levulinate esters at mild process conditions. 

Aluminum chloride‐catalyzed conversion of levulinic acid to methyl levulinate: optimization and kinetics

2020 ◽  
Vol 95 (8) ◽  
pp. 2251-2260
Author(s):  
Yanli Xu ◽  
Pengkun Guo ◽  
Chun Chang ◽  
Pan Li ◽  
Shiqiang Zhao ◽  
...  
Keyword(s):  
Aluminum Chloride ◽  
Levulinic Acid ◽  
Methyl Levulinate

Biocatalytic upgrading of levulinic acid to methyl levulinate in green solvents

2019 ◽  
Vol 81 ◽  
pp. 33-38 ◽  
Author(s):  
Xiaohui Di ◽  
Yu Zhang ◽  
Junying Fu ◽  
Qiang Yu ◽  
Zhongming Wang ◽  
...  
Keyword(s):  
Levulinic Acid ◽  
Green Solvents ◽  
Methyl Levulinate

Palladium-catalyzed oxidative CC bond cleavage with molecular oxygen: one-pot synthesis of quinazolinones from 2-amino benzamides and alkenes

2018 ◽  
Vol 5 (18) ◽  
pp. 2734-2738 ◽  
Author(s):  
Wei Liu ◽  
Ge Wu ◽  
Wenxia Gao ◽  
Jinchang Ding ◽  
Xiaobo Huang ◽  
...  
Keyword(s):  
Molecular Oxygen ◽  
Functional Group ◽  
Bond Cleavage ◽  
Oxidative Cleavage ◽  
One Pot ◽  
One Pot Synthesis ◽  
Terminal Alkenes ◽  
Palladium Catalyzed ◽  
Quinazolinone Derivatives

Palladium-catalyzed oxidative cleavage/cyclization has been disclosed for the concise synthesis of various quinazolinone derivatives from readily available 2-aminobenzamides and terminal alkenes with excellent functional group tolerance.

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