624-09-9Relevant articles and documents
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.
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.
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.
Metal complex catalysts and method for catalytically reducing carboxylic acids
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Paragraph 0085-0144; 0153; 0154; 0167-0168; 0178-0179, (2020/06/20)
The invention relates to a metal complex catalyst, which contains at least one of metal complexes with a chemical formula comprising a structural unit represented by a formula I. According to the invention, the center metal of the metal complex catalyst is iridium, and the metal complex catalyst is composed of pentamethylcyclopentadienyl, a bitetrahydropyrimidine ligand and proper coordination anions; the metal complex catalyst has activity on a carboxylic acid reduction reaction, and a carboxylic acid compound is reduced into an alcohol compound in the presence of hydrogen; and the method ismild in reaction condition, can be carried out at room temperature, and is good in catalytic performance and high in reduction product yield.
Aerobic Self-Esterification of Alcohols Assisted by Mesoporous Manganese and Cobalt Oxide
Moharreri, Ehsan,Biswas, Sourav,Deljoo, Bahareh,Kriz, David,Lim, Seyoung,Elliott, Sarah,Dissanayake, Shanka,Dabaghian, Marina,Aindow, Mark,Suib, Steven L.
, p. 3413 - 3422 (2019/08/01)
Aerobic self-esterification of primary alcohols catalyzed by mesoporous metal oxides (manganese and cobalt oxides) is reported under base and solvent free conditions. For a range of aliphatic alcohols, up to 90 % conversions to esters was achieved. The catalytic reaction is likewise applicable to neat aldehydes as substrates with yields of up to 86 %. High pressure batch reaction for ethanol to ethyl acetate led to 22 % yield. Isotope labeling studies indicated decarboxylation on the catalyst surface. Mechanistic and kinetic experiments implicate oxygen rebound and α-carbon removal as intermediate steps. Mesoporous cobalt oxide showed about 20 % higher catalytic activity compared to mesoporous manganese oxide.
Oxidative esterification of primary alcohols at room temperature under aqueous medium
Reddy, N. Naresh Kumar,Ravi, Chitrakar,Adimurthy, Subbarayappa
, p. 1663 - 1670 (2018/06/15)
Oxidative esterification of aliphatic primary alcohols with bromide and bromate couple in aqueous acidic medium at room temperature is reported with a wide range of substrate scope for both aliphatic and cyclic alcohols and obtained excellent yields of products.
Cobalt-Catalyzed Acceptorless Dehydrogenative Coupling of Primary Alcohols to Esters
Paudel, Keshav,Pandey, Bedraj,Xu, Shi,Taylor, Daniela K.,Tyer, David L.,Torres, Claudia Lopez,Gallagher, Sky,Kong, Lin,Ding, Keying
supporting information, p. 4478 - 4481 (2018/08/09)
A novel catalytic system with a tripodal cobalt complex is developed for efficiently converting primary alcohols to esters. KOtBu is found essential to the transformation. A preliminary mechanistic study suggests a plausible reaction route that involves an initial Co-catalyzed dehydrogenation of alcohol to aldehyde, followed by a Tishchenko-type pathway to ester mediated by KOtBu.
Dehydrogenative coupling of alcohols to esters on a silica polyamine composite by immobilized PNN and PONOP pincer complexes of ruthenium
Goni, Md Abdul,Rosenberg, Edward,Gobetto, Roberto,Chierotti, Michele
, p. 213 - 228 (2017/07/22)
Heterogenization of catalytically important homogeneous catalysts on solid supports has become an expanding area of research. PNN and PONOP ruthenium pincer complexes were immobilized on a silica poly(allylamine) composite, BP-1 by a two-step Mannich reaction. The complexes on BP-1 were characterized by solid state NMR, FT-IR, elemental analysis, and metal digestion studies. Model solution experiments were carried out to determine the site of electrophilic substitution on the pyridine ring of the pincer complexes and revealed substitution in both the meta- and para-position. The catalytic reactivity of immobilized (PNN)RuH(Cl)(CO) and (PONOP)RuH(Cl)(CO) on BP-1 was studied for the dehydrogenative coupling of alcohols to esters with the liberation of H2. Moderate to good ester yields were realized with both immobilized systems without using the base required for the homogeneous reaction and also in the presence of KOH. The homogeneous model reactions required a base for ester formation. The amine functionality on BP-1 served as the base to generate the active pincer catalyst on the BP-1 surface. Both immobilized catalysts were recycled for multiple alcohol reaction cycles. Four-step control experiments were carried out using an alcohol and both immobilized systems. The results revealed the heterogeneity of the alcohol catalysis by both BP-1-Ru-PNN and BP-1-Ru-PONOP systems. This study has opened a new catalytic methodology for reactions where base is required for catalyst activation, by using a solid support with basic functionality.
A TEMPO-like nitroxide combined with an alkyl-substituted pyridine: An efficient catalytic system for the selective oxidation of alcohols with iodine
Kashparova, Vera P.,Klushin, Victor A.,Zhukova, Irina Yu.,Kashparov, Igor S.,Chernysheva, Daria V.,Il'chibaeva, Irina B.,Smirnova, Nina V.,Kagan, Efim Sh.,Chernyshev, Victor M.
supporting information, p. 3517 - 3521 (2017/10/05)
An efficient method for the oxidation of alcohols to aldehydes or ketones in a two-phase CH2Cl2/NaHCO3 (aq.) system, using iodine and catalytic amounts of 4-acetylamino-2,2,6,6-tetramethylpiperidine-1-oxyl and 2,4,6-trimethylpyridine, was developed. The performance of the method was demonstrated by the selective oxidation of 37 variously substituted alcohols in ≥90% yield, including the gram-scale synthesis of the important chemical 2,5-diformylfuran from biomass-derived 5-hydroxylmethylfurfural.
Solvent- and base-free synthesis of wax esters from fatty acid methyl esters by consecutive one-pot, two-step catalysis
Nguyen,Raffa,Morin,Desset,Capet,Nardello-Rataj,Dumeignil,Gauvin
supporting information, p. 5665 - 5673 (2017/12/06)
The one-pot, two-step synthesis of wax esters was successfully conducted by consecutive homogeneous ruthenium-catalysed hydrogenation-dehydrogenation reactions of fatty acid methyl esters, in the absence of solvent and of base additive. Under optimized conditions, excellent conversion and selectivity were reached. Furthermore, physicochemical investigations revealed that the resulting compounds display properties similar to benchmark commercial products extracted from natural sources of lesser availability compared to the herein considered bioresources, making this chemical route very promising regarding further potential industrial implementation.
