2173-56-0Relevant articles and documents
Unraveling the role of low coordination sites in a cu metal nanoparticle: A step toward the selective synthesis of second generation biofuels
Scotti, Nicola,Dangate, Milind,Gervasini, Antonella,Evangelisti, Claudio,Ravasio, Nicoletta,Zaccheria, Federica
, p. 2818 - 2826 (2014)
The acidity of a prereduced Cu/SiO2 catalyst was extensively investigated by means of FT-IR of adsorbed pyridine and by titration with 2-phenylethylamine in cyclohexane. Comparison with the parent CuO/SiO 2 material, which was alread
Selective oxidation of primary alkanols into the "symmetrical" esters with the H2O2-MBr-HCl system
Nikishin,Sokova,Kapustina
, p. 310 - 312 (2011)
Oxidation of linear or branched primary alkanols with H2O 2-MBr (M = Li, Na, K)-HCl system in water affords the corresponding "symmetrical" esters in almost quantitative yield.
Valeric Biofuel Production from γ-Valerolactone over Bifunctional Catalysts with Moderate Noble-Metal Loading
Martínez Figueredo, Karla G.,Virgilio, Emanuel M.,Segobia, Darío J.,Bertero, Nicolás M.
, p. 1342 - 1346 (2021)
SiO2-Al2O3-supported Ru, Ir and Pt-based catalysts with moderate metal loading (1 %) were tested for the first time in the production of pentyl valerate (PV) in liquid phase from γ-valerolactone, pentanol (in excess) and H2. The acidity of these bifunctional catalysts, plays a key role in the one-pot process comprising two consecutive acid-catalyzed reactions and a metal-catalyzed one. Metal dispersion also shown to be relevant for the conversion of the pentyl pentenoate intermediate into PV by hydrogenation over the metal sites. Pt/SA catalyst with the highest surface acidity and metal dispersion reached optimal GVL conversion with a PV yield of 90.0 % after 10 h, exhibiting a PV productivity of 300 mmol/gM.h, i. e. a value between three and four times higher than the best result reported until now (91.8 mmol/gM.h). These findings highlight the potential that noble metal-based catalyst with moderate metal loading have in the valorization of biomass-derived platform molecules such as γ-valerolactone.
Performance of Candida rugosa lipase supported on nanocellulose-silica-reinforced polyethersulfone membrane for the synthesis of pentyl valerate: Kinetic, thermodynamic and regenerability studies
Chandren, Sheela,Elias, Nursyafiqah,Lau, Woei Jye,Wahab, Roswanira Abdul
, (2021/09/16)
The present study reports the groundwork for preparing a greener catalyst, Candida rugosa lipase (CRL), supported on biomass-based nanocellulose-silica-reinforced polyethersulfone membrane (NC-SiO2-PES) and proved its stability in synthesizing pentyl valerate. The NC-SiO2-PES/CRL-catalyzed synthesis of the ester exhibited a ping-pong bi-bi mechanism, with a high Vmax value and low Km value over the free CRL, confirming the former's greater substrate affinity. The kinetics data demonstrated that the NC-SiO2-PES/CRL was catalytically more efficient than its free counterpart. The lower Michaelis-Menten constant of NC-SiO2-PES/CRL for pentanol (Km,B = 43.53 mM) than valeric acid (Km,A = 82.03 mM) indicates that pentanol was favored over the latter. Pertinently, the higher thermal deactivation values of NC-SiO2-PES/CRL indicated that the NC-SiO2-PES membrane successfully enhanced CRL thermal stability, and the process followed first-order kinetics (R2 > 0.95). The NC-SiO2-PES/CRL has a slightly greater activation energy (Ea) and activation energy for thermal denaturation (Ed) over the free CRL. NC-SiO2-PES/CRL also exhibited extended operational stability, with a robust half-life of ～150 h and the absence of leached protein after 60 min of agitation. The NC-SiO2-PES/CRL's ability to be regenerated chemically and ultrasonically and reused without significant loss in enzyme activity denotes its potential cost-saving to produce pentyl valerate.
Solvent-free oxidation of straight-chain aliphatic primary alcohols by polymer-grafted vanadium complexes
Chaudhary, Nikita,Haldar, Chanchal,Kachhap, Payal
, (2021/12/02)
Oxidovanadium(IV) complexes [VO(tertacac)2] (1), [VO(dipd)2] (2), and [VO(phbd)2] (3) were synthesized by reacting [VO(acac)2] with 2,2,6,6-tetramethyl-3,5-hepatanedione, 1,3-diphenyl-1,3-propanedione, and 1-phenyl-1,3-butanedione, respectively. Imidazole-modified Merrifield resin was used for the heterogenization of complexes 1–3. During the process of heterogenization, the V4+ center in complex 2 converts into V5+, whereas the other two complexes 1 and 3 remain in the oxidovanadium(IV) state in the polymer matrix. Theoretically, calculated IPA values of 1–3 suggest that 2 is prone to oxidation compared with 1 and 3, which was also supported by the absence of EPR lines in 5. Polymer-supported complexes Ps-Im-[VIVO(tertacac)2] (4), Ps-Im-[VVO2(dipd)2] (5), and Ps-Im-[VIVO(phbd)2] (6) were applied for the solvent-free heterogenous oxidation of a series of straight-chain aliphatic alcohols in the presence of H2O2 at 60°C and showed excellent substrate conversion specially for the alcohols with fewer carbon atoms. Higher reaction temperature improves the substrate conversion significantly for the alcohols containing more carbon atoms such as 1-pentanol, 1-hexanol, and 1-heptanol while using optimized reaction conditions. However, alcohols with fewer carbon atoms seem less affected by reaction temperatures higher than the optimized temperature. A decreasing trend in the selectivity(%) of carboxylic acid was observed with increasing carbon atoms among the examined alcohols, whereas the selectivity towards aldehydes increased. The order of efficiency of the supported catalysts is 4 > 6 > 5 in terms of turnover frequency (TOF) values and substrate conversion, further supported by theoretical calculations.
Aerobic oxidation and oxidative esterification of alcohols through cooperative catalysis under metal-free conditions
Karimi, Babak,Ghahremani, Mina,Vali, Hojatollah,Ciriminna, Rosaria,Pagliaro, Mario
supporting information, p. 8897 - 8900 (2021/09/10)
The ABNO@PMO-IL-Br material obtained by anchoring 9-azabicyclo[3.3.1]nonane-3-oneN-oxyl (keto-ABNO) within the mesopores of periodic mesoporous organosilica with bridged imidazolium groups is a robust bifunctional catalyst for the metal-free aerobic oxidation of numerous primary and secondary alcohols under oxygen balloon reaction conditions. The catalyst, furthermore, can be successfully employed in the first metal-free self-esterification of primary aliphatic alcohols affording valued esters.
Disproportionation of aliphatic and aromatic aldehydes through Cannizzaro, Tishchenko, and Meerwein–Ponndorf–Verley reactions
Sharifi, Sina,Sharifi, Hannah,Koza, Darrell,Aminkhani, Ali
, p. 803 - 808 (2021/07/20)
Disproportionation of aldehydes through Cannizzaro, Tishchenko, and Meerwein–Ponndorf–Verley reactions often requires the application of high temperatures, equimolar or excess quantities of strong bases, and is mostly limited to the aldehydes with no CH2 or CH3 adjacent to the carbonyl group. Herein, we developed an efficient, mild, and multifunctional catalytic system consisting AlCl3/Et3N in CH2Cl2, that can selectively convert a wide range of not only aliphatic, but also aromatic aldehydes to the corresponding alcohols, acids, and dimerized esters at room temperature, and in high yields, without formation of the side products that are generally observed. We have also shown that higher AlCl3 content favors the reaction towards Cannizzaro reaction, yet lower content favors Tishchenko reaction. Moreover, the presence of hydride donor alcohols in the reaction mixture completely directs the reaction towards the Meerwein–Ponndorf–Verley reaction. Graphic abstract: [Figure not available: see fulltext.].
A robust NNP-type ruthenium (II) complex for alcohols dehydrogenation to esters and pyrroles
Chai, Huining,Zhang, Guangyao,Tan, Weiqiang,Ma, Jiping
, (2019/12/03)
A Ru (II) complex bearing pyridyl-based benzimidazole-phosphine tridentate NNP ligand was synthesized and structurally characterized by NMR, IR. The complex can efficiently and selectively catalyze the acceptorless dehydrogenation of primary alcohols to esters under relatively mild conditions and the synthesis of pyrroles by means of the reactions of secondary alcohols and β-amino alcohols through acceptorless deoxygenation condensation.
Aldehyde effect and ligand discovery in Ru-catalyzed dehydrogenative cross-coupling of alcohols to esters
Jiang, Xiaolin,Zhang, Jiahui,Zhao, Dongmei,Li, Yuehui
supporting information, p. 2797 - 2800 (2019/03/27)
The presence of different aldehydes is found to have a significant influence on the catalytic performance when using PN(H)P type ligands for dehydrogenation of alcohols. Accordingly, hybrid multi-dentate ligands were discovered based on an oxygen-transfer alkylation of PNP ligands by aldehydes. The relevant Ru-PNN(PO) system provided the desired unsymmetrical esters in good yields via acceptorless dehydrogenation of alcohols. Hydrogen bonding interactions between the phosphine oxide moieties and alcohol substrates likely assisted the observed high chemoselectivity.
USE OF A RUTHENIUM CATALYST COMPRISING A TETRADENTATE LIGAND FOR HYDROGENATION OF ESTERS AND/OR FORMATION OF ESTERS AND A RUTHENIUM COMPLEX COMPRISING SAID TETRADENTATE LIGAND
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Page/Page column 27, (2019/08/20)
The present invention relates to the use of a transition metal catalyst TMC1, which comprises a transition metal M selected from metals of groups 7, 8, 9 and 10 of the periodic table of elements according to IUPAC and a tetradentate ligand of formula I wherein R1 are identical or different and are each an organic radical having from 1 to 40 carbon atoms, and R2 are identical or different and are each an organic radical having from 1 to 40 carbon atoms, as catalyst in processes for formation of compounds comprising at least one carboxylic acid ester functional group -O-C(=O)- starting from at least one primary alcohol and/or hydrogenation of compounds comprising at least one carboxylic acid ester functional group -O-C(=O)-. The present invention further relates to a process for hydrogenation of a compound comprising at least one carboxylic acid ester functional group -O-C(=O)-, to a process for the formation of a compound comprising at least one carboxylic acid ester functional group -O-C(=O)- by dehydrogenase coupling of at least one primary alcohol with a second alcoholic OH-group, to a transition metal complex comprising the tetradentate ligand of formula I and to a process for preparing said transition metal complex.
