cas 88-14-2, 2-Furoic acid | Articles data

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Kinetic and mechanistic analysis of oxidation of 2-furoic hydrazide by hexachloroirradate(IV) in a wide pH range
Oxidation of 2-furoic hydrazide (FH) by hexachloroiridate(IV) ([IrCl6]2?) was studied kinetically in a wide pH range in aqueous solution of 1.0?M ionic strength. The oxidation reaction followed well-defined second-order kinetics: ? d[IrCl6 2?]/dt = k′[FH]tot[IrCl6 2?], where [FH]tot denotes the total concentration of FH and k′ stands for the observed second-order rate constants. The established k′–pH profile displays that k′ increases drastically with pH and a plateau region exists between pH 4 and 6. A stoichiometric ratio of Δ[FH]tot/Δ[IrCl6 2?] = 1/4?was revealed by spectrophotometric titrations. 1H NMR spectroscopic studies indicated that FH was cleanly oxidized to 2-furoic acid. The kinetic data suggest a reaction mechanism in which all the three protolysis species of FH react with [IrCl6]2? in parallel, forming the rate-determining steps. Two stabilized hydrazyl radicals are generated in the rate-determining steps, in which a single electron is transferred to [IrCl6]2?. The two hydrazyl radicals react rapidly in consecutive steps requiring 3?mol of Ir(IV) to form 2-furoic acid as the final product. Rate constants of the rate-determining steps were deduced through a simulation of the rate expression to the k′–pH dependency data. Values of these rate constants demonstrate that the three protolysis species of FH have a huge reactivity span, changing by about 109 times toward reduction in [IrCl6]2? and that FH can be readily oxidized in neutral and basic media. Rapid scan spectra and the measured activation parameters suggest that an outer-sphere electron transfer is probably taking place in each of the rate-determining steps. This is the first kinetic study on the oxidation reactions of FH and provides concurrently the protolysis constants of FH (pKa1 = 3.04 ± 0.08 and pKa2 = 11.6 ± 0.1) at 25.0?°C and 1.0?M ionic strength.
Yao, Haiping,Tian, Hongwu,Xu, Liyao,Xia, Yanqing,Zhou, Li,Liu, Chunli,Shi, Tiesheng
p. 771 - 777
(2019)
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High performance of Au/ZTC based catalysts for the selective oxidation of bio-derivative furfural to 2-furoic acid 1
Furfural is a platform bio-molecule for which is valuable to develop new green upgrading processes in biorefinery. We report here for the first time the high performance of Au/ZTC catalyst for the selective oxidation of furfural to 2-furoic acid, as first step to develop electrodes. The ordered nanostructure and high surface area of BEA structure replica ZTC allows to develop 3D-type electrodes. Au/ZTC catalyst shows higher performance than commercial Vulcan, used as reference conductive carbon in fuel cells. The weak acidity on ZTC avoids decarboxylation and esterification reactions, leading to about 90% of furfural conversion fully selectivity to 2-furoic acid.
Centi, Gabriele,Cozza, Daniela,Giordano, Girolamo,Giorgianni, Gianfranco,Lanzafame, Paola,Migliori, Massimo,Papanikolaou, Georgia,Perathoner, Siglinda
(2021)
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Transformation of Thioacids into Carboxylic Acids via a Visible-Light-Promoted Atomic Substitution Process
A visible-light-promoted atomic substitution reaction for transforming thiocacids into carboxylic acids with dimethyl sulfoxide (DMSO) as the oxygen source has been developed, affording various alkyl and aryl carboxylic acids in over 90% yields. The atomic substitution process proceeds smoothly through the photochemical reactivity of the formed hydrogen-bonding adduct between thioacids and DMSO. A DMSO-involved proton-coupled electron transfer (PCET) and the simultaneous generation of thiyl and hydroxyl radicals are proposed to be key steps for realizing the transformation.
Fu, Qiang,Liang, Fu-Shun,Lou, Da-Wei,Pan, Gao-Feng,Wang, Rui,Wu, Min,Xie, Kai-Jun
p. 2020 - 2024
(2022/03/31)

Cleavage of Carboxylic Esters by Aluminum and Iodine
A one-pot procedure for deprotecting carboxylic esters under nonhydrolytic conditions is described. Typical alkyl carboxylates are readily deblocked to the carboxylic acids by the action of aluminum powder and iodine in anhydrous acetonitrile. Cleavage of lactones affords the corresponding ω-iodoalkylcarboxylic acids. Aryl acetylates undergo deacetylation with the participation of the neighboring group. This method enables the selective cleavage of alkyl carboxylic esters in the presence of aryl esters.
Sang, Dayong,Yue, Huaxin,Fu, Yang,Tian, Juan
p. 4254 - 4261
(2021/03/09)

Synthesis, biological evaluation and molecular docking studies of indeno [1, 2-c] pyrazol derivatives as inhibitors of mitochondrial malate dehydrogenase 2 (MDH2)
Hypoxia inducible factor-1 (HIF-1) is a pivotal transcription factor, which is strongly correlated with the induction of angiogenesis, tumor survival, metastasis, and cell proliferation, making it a pivotal therapeutic target for solid tumor therapeutic agents. Herein, a new series of multi-functional chemical probes were designed including principal groups, viz. adamantyl and indene, at various locations of the parent compound LW6. Molecular docking studies were performed on the designed compounds and their relationship with HIF-1α and malate dehydrogenase 2 (MDH2). Inhibition of MDH2 by our compounds was expected to decrease the NADH level. Indeed, treatment of the breast cancer cell line 4T1 led to a strong reduction of the NADH concentration. The greatest reduction in NADH production in mitochondria was observed with (E)-3-(4-((3r, 5r, 7r)-adamantan-1-yl) phenoxy)-N-(5-(piperidine-1-carbonyl)-1, 4-dihydroindeno [1, 2-c] pyrazol-3-yl) acrylamide (18: IC50 = 59 nM), and has the best inhibitory potential under hypoxic conditions (MCF-7: IC50 = 57 nM). This compound also gave one of the highest docking “higher than the score obtained with LW6 in parallel (?31.63 kcal/mol) in the initial docking runs (PDB Code: 4WLO). Other related compounds with good yields were also synthesized from docking results, and all the synthesized compounds (14, 18, 22, 26, 29, 30) were evaluated in vitro on human adenocarcinoma cell lines.
Ahmadi, Farzaneh,Engel, Matthias,Baradarani, Mehdi M.
(2021/03/15)

Au-catalyzed electrochemical oxidation of alcohols using an electrochemical column flow cell
A novel green system for the electrochemical oxidation of alcohols is demonstrated using a column flow cell. Voltammetric analysis revealed that the oxidation of 1-phenylethanol and benzaldehyde are promoted by using both an Au-electrode and an alkaline medium. To conduct such reaction with a column flow cell, we developed a method to modify a carbon-fiber thread with Au nanoparticles. The column carbon-fiber thread electrode modified with Au nanoparticles showed a high surface area, enabling the efficient electrochemical oxidation of various alcohols.
Suga, Tatsuya,Shida, Naoki,Atobe, Mahito
(2021/02/09)

Hydrogen-Binding-Initiated Activation of O?H Bonds on a Nitrogen-Doped Surface for the Catalytic Oxidation of Biomass Hydroxyl Compounds
Hydrogen binding of molecules on solid surfaces is an attractive interaction that can be used as the driving force for bond activation, material-directed assembly, protein protection, etc. However, the lack of a quantitative characterization method for hydrogen bonds (HBs) on surfaces seriously limits its application. We measured the standard Gibbs free energy change (ΔG0) of on-surface HBs using NMR. The HB-accepting ability of the surface was investigated by comparing ΔG0 values employing the model biomass platform 5-hydroxymethylfurfural on a series of Co-N-C-n catalysts with adjustable electron-rich nitrogen-doped contents. Decreasing ΔG0 improves the HB-accepting ability of the nitrogen-doped surface and promotes the selectively initiated activation of O?H bonds in the oxidation of 5-hydroxymethylfurfural. As a result, the reaction kinetics is accelerated. In addition to the excellent catalytic performance, the turnover frequency (TOF) for this oxidation is much higher than for reported non-noble-metal catalysts.
Liu, Xin,Luo, Yang,Ma, Hong,Zhang, Shujing,Che, Penghua,Zhang, Meiyun,Gao, Jin,Xu, Jie
p. 18103 - 18110
(2021/07/14)

Cu2O-Catalyzed Conversion of Benzyl Alcohols Into Aromatic Nitriles via the Complete Cleavage of the C≡N Triple Bond in the Cyanide Anion
Nitrogen transfer from cyanide anion to an aldehyde is emerging as a promising method for the synthesis of aromatic nitriles. However, this method still suffers from a disadvantage that a use of stoichiometric Cu(II) or Cu(I) salts is required to enable the reaction. As we report herein, we overcame this drawback and developed a catalytic method for nitrogen transfer from cyanide anion to an alcohol via the complete cleavage of the C≡N triple bond using phen/Cu2O as the catalyst. The present condition allowed a series of benzyl alcohols to be smoothly converted into aromatic nitriles in moderate to high yields. In addition, the present method could be extended to the conversion of cinnamic alcohol to 3-phenylacrylonitrile.
Liu, Wenbo,Tang, Peichen,Zheng, Yi,Ren, Yun-Lai,Tian, Xinzhe,An, Wankai,Zheng, Xianfu,Guo, Yinggang,Shen, Zhenpeng
p. 3509 - 3513
(2021/10/04)

An Anionic, Chelating C(sp3)/NHC ligand from the Combination of an N-heterobicyclic Carbene and Barbituric Heterocycle
The coordination chemistry of the anionic NHC1-based on an imidazo[1,5-a]pyridin-3-ylidene (IPy) platform substituted at the C5 position by an anionic barbituric heterocycle was studied with d6(Ru(II), Mn(I)) and d8(Pd(II), Rh(I), Ir(I), Au(III)) transition-metal centers. While the anionic barbituric heterocycle is planar in the zwitterionic NHC precursor 1·H, NMR spectroscopic analyses supplemented by X-ray diffraction studies evidenced the chelating behavior of ligand 1-through the carbenic and the malonic carbon atoms in all of the complexes, resulting from a deformation of the lateral barbituric heterocycle. The complexes were obtained by reaction of the free carbene with the appropriate metal precursor, except for the Au(III) complex 10, which was obtained by oxidation of the antecedent gold(I) complex [AuCl(1)]?with PhICl2as an external oxidant. During the course of the process, the kinetic gold(I) intermediate 9 resulting from the oxidation of the malonic carbon of the barbituric moiety was isolated upon crystallization from the reaction mixture. The νCOstretching frequencies recorded for complex [Rh(1)(CO)2] (5) demonstrated the strong donating character of the malonate-C(sp3)/NHC ligand 1-. The ruthenium complex [Ru(1)Cl(p-cymene)] (11) was implemented as a precatalyst in the dehydrogenative synthesis of carboxylic acid derivatives from primary alcohols and exhibited high activities at low catalyst loadings (25-250 ppm) and a large tolerance toward functional groups.
Benaissa, Idir,Gajda, Katarzyna,Vendier, Laure,Lugan, No?l,Kajetanowicz, Anna,Grela, Karol,Michelet, Véronique,César, Vincent,Bastin, Stéphanie
p. 3223 - 3234
(2021/09/30)

Preparation method for producing furan ammonium salt by using 2-acetylfuran
The invention discloses a preparation method for producing furan ammonium salt by using 2-acetylfuran. The preparation method comprises the following steps: preparation of furanone acid, generation of 2-methoxyamine-2-furanacetic acid through oximation, purification of oximation reaction liquid and ammonification treatment. 2-acetylfuran is used as a raw material, the furan ammonium salt is obtained through oxidation, oximation, extraction and ammonification operation, a compound catalyst is added in the oxidation process, and the reaction speed is further increased through addition of transition metal salt; the transition metal salt and the catalytic promoter are combined with each other, and the catalytic promoter is used for synergistically promoting the catalytic performance of the transition metal salt, so that the conversion rate of furanone acid is further improved.
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Paragraph 0031-0034; 0046-0049; 0061-0064; 0078-0081; 0093

(2021/06/23)

Preparation method of furoic acid
The invention provides a preparation method of furoic acid, and the method comprises the following steps of: under the condition of air and/or oxygen, contacting an aqueous solution of furfural with a catalyst for catalytic oxidation reaction to prepare furoic acid, wherein the catalyst is obtained by the following steps of: mixing a carrier, an alkaline nitrogen-containing compound and an active component precursor and placing the mixture in a solvent, performing heating under a water bath condition and carrying out reflux stirring treatment; sequentially carrying out drying treatment and roasting reduction treatment on the mixture subjected to the reflux stirring treatment to obtain the catalyst; wherein the active component precursor is selected from one or more of rhodium chloride, palladium chloride, chloroplatinic acid and ruthenium chloride, and the carrier is selected from one or more of activated carbon, graphite, fullerene and graphene oxide. The catalyst adopted by the method is high in activity, the product yield is high, the reaction does not need to be carried out in an alkaline environment, the reaction process is environment-friendly, the product is easy to separate, and the problem of complicated subsequent acid treatment in the traditional furoic acid preparation process is solved.
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Paragraph 0065-0096

(2021/05/12)

Process for preparing 2-5 - furandicarboxylic acid from furfural
The invention belongs to the technical field of organic synthesis and discloses a process for preparing 2, 5 - furandicarboxylic acid from furfural. The process comprises the following steps: (1) adjusting the acid-base regulator. The nano copper oxide powder is mixed with water to 60 - 100 °C, furfural is added, air is continuously introduced, the nano copper oxide is filtered and removed after reaction, the mother solution is cooled down to 0 - 10 °C, and potassium bran is filtered. (2) The mother liquor obtained after filtration through step (1) is continuously added with potassium carbonate and the nano copper oxide removed in step (1), the step (1) 0 - n is repeated, and the obtained potassium bran potassium is combined. (3) The obtained potassium chaff, the basic compound and the solvent are introduced into carbon dioxide to obtain 2 and 5 - furandicarboxylic acid after the reaction, and 2, 5 - furandicarboxylic acid is obtained after the reaction. The solvent and the catalyst used in the process are low in price, the solvent and the catalyst can be recycled, the reaction cost is low, the waste water waste is few, the process is simple, efficient, economical and environment-friendly, and is suitable for large-scale industrial production.
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Paragraph 0032-0049

(2021/10/27)

Preparation method of furoic acid
The invention discloses a preparation method of furoic acid. The preparation method comprises the following step: subjecting furfural, a light stabilizer, a cocatalyst and a solvent to reacting in thepresence of an oxygen source to obtain furoic acid. The method provided by the invention has the advantages of high selectivity, few byproducts, mild reaction conditions and certain industrial application prospect.
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Paragraph 0022-0055

(2021/02/10)

Synthesis of amides and esters containing furan rings under microwave-assisted conditions
In this work, we present a novel method for the synthesis of ester and amide derivatives containing furan rings (furfural derivatives) under mild synthetic conditions supported by microwave radiation. N-(Furan-2-ylmethyl)furan-2-carboxamide and furan-2-ylmethyl furan-2-carboxylate were produced using 2-furoic acid, furfurylamine, and furfuryl alcohol. The reactions were carried out in a microwave reactor in the presence of effective coupling reagents: DMT/NMM/TsO? or EDC. The reaction time, the solvent, and the amounts of the substrates were optimized. After crystallization or flash chromatography, the final compounds were isolated with good or very good yields. Our method allows for the synthesis of N-blocked amides using N-blocked amino acids (Boc, Cbz, Fmoc) and amine. As well as compounds with a monoamide and ester moiety, products with diamides and diester bonds (N,N-bis(furan-2-ylmethyl) furan-2,5-dicarboxamide, bis(furan-2-ylmethyl) furan-2,5dicarboxylate, and furan-3,4-diylbis(methylene) bis(furan-2-carboxylate)) were synthesized with moderate yields in the presence of DMT/NMM/TsO– or EDC, using 2,5-furan-dicarboxylic acid and 3,4-bis(hydroxymethyl)furan as substrates.
Janczewski, ?ukasz,Zieliński, Dariusz,Kolesińska, Beata
p. 265 - 280
(2021/03/17)

Combination of Highly Efficient Electrocatalytic Water Oxidation with Selective Oxygenation of Organic Substrates using Manganese Borophosphates
One of the key catalytic reactions for life on earth, the oxidation of water to molecular oxygen, occurs in the oxygen-evolving complex of the photosystem II (PSII) mediated by a manganese-containing cluster. Considerable efforts in this research area embrace the development of efficient artificial manganese-based catalysts for the oxygen evolution reaction (OER). Using artificial OER catalysts for selective oxygenation of organic substrates to produce value-added chemicals is a worthwhile objective. However, unsatisfying catalytic performance and poor stability have been a fundamental bottleneck in the field of artificial PSII analogs. Herein, for the first time, a manganese-based anode material is developed and paired up for combining electrocatalytic water oxidation and selective oxygenations of organics delivering the highest efficiency reported to date. This can be achieved by employing helical manganese borophosphates, representing a new class of materials. The uniquely high catalytic activity and durability (over 5 months) of the latter precursors in alkaline media are attributed to its unexpected surface transformation into an amorphous MnOx phase with a birnessite-like short-range order and surface-stabilized MnIII sites under extended electrical bias, as unequivocally demonstrated by a combination of in situ Raman and quasi in situ X-ray absorption spectroscopy as well as ex situ methods.
Menezes, Prashanth W.,Walter, Carsten,Chakraborty, Biswarup,Hausmann, Jan Niklas,Zaharieva, Ivelina,Frick, Achidi,von Hauff, Elizabeth,Dau, Holger,Driess, Matthias
(2021/02/01)

Meso-Carbazole substituted palladium porphyrins: Efficient catalysts for visible light induced oxidation of aldehydes
The A3B and A2B2 type porphyrins having N-butylcarbazole and p-cyanophenyl groups are synthesized and characterized. Their palladium complexes have also been prepared and utilized as catalysts for the photo-oxidation reactions of aromatic aldehydes in good yields. Pd(II)porphyrins displayed decent phosphorescence at a670 nm and were able to generate singlet oxygen upon light irradiation. The calculated singlet oxygen quantum yields for Pd(II)porphyrins were between 57% and 73%. The photo-catalytic application of Pd(II)porphyrins for aerobic oxidation of aromatic aldehydes is demonstrated.
Janaagal, Anu,Pandey, Vijayalakshmi,Sabharwal, Sudhir,Gupta, Iti
p. 571 - 581
(2021/05/05)

(Hexamethylbenzene)Ru catalysts for the Aldehyde-Water Shift reaction
The Aldehyde-Water Shift (AWS) reaction uses H2O as a benign oxidant to convert aldehydes to carboxylic acids, producing H2, a valuable reagent and fuel, as its sole byproduct. (Hexamethylbenzene)RuIIcomplexes are demonstrated to have higher activity and selectivity (up to 95%) for AWS over disproportionation than previously reported catalysts.
Phearman, Alexander S.,Moore, Jewelianna M.,Bhagwandin, Dayanni D.,Goldberg, Jonathan M.,Heinekey, D. Michael,Goldberg, Karen I.
supporting information
p. 1609 - 1615
(2021/03/09)

Biocatalytic transformation of furfural into furfuryl alcohol using resting cells of Bacillus cereus
The bioconversion of furfural to furfuryl alcohol is an attractive route in biomass valorization that could replace traditional contaminant methods. The use of whole cells has been explored for this purpose. Bacillus cereus without previous treatment with furanic compounds was used to selectively obtain furfuryl alcohol. Growing and resting cells were employed. Using growing cells of B. cereus, lower yields to alcohol were obtained because of furfural toxicity. However, employing resting cells it was possible to reach higher yields to furfuryl alcohol. Optimal operative conditions were studied: different concentrations of furfural, glucose and molybdenum, pH, and temperature. Thus, glucose (100 mM) and molybdenum (0.1 mM) were added to maintain cell biomass obtaining a yield to furfuryl alcohol close to 80% at 30 °C, pH 7.2 from 30 mM of furfural.
Rodríguez M, Alejandra,Rache, Leidy Y.,Brijaldo, María H.,Romanelli, Gustavo P.,Luque, Rafael,Martinez, José J.
p. 220 - 225
(2021/02/16)

Valorization of furfural using ruthenium (II) complexes containing phosphorus-nitrogen ligands under homogeneous transfer hydrogen condition
In this paper, we report the catalytic activity of a series of ruthenium (II) complexes containing phosphorus-nitrogen bidentated (P-N) ligands in the hydrogenation of furfural via hydrogen transfer reaction using two hydrogen donor sources: 2-propanol in basic medium and formic acid under mild conditions. The results showed that all the ruthenium complexes studied are catalytically active in the hydrogenation of furfural by hydrogen transfer reaction; they showed 100% conversion with both hydrogen sources. However, selectivities towards the formation of furfuryl alcohol were better when formic acid was used. It was also found that the reaction studied in a basic medium competes with the Cannizzaro reaction, obtaining furfuryl alcohol and furoic acid in a 70/30 ratio; on the other hand, using formic acid as the hydrogen source yields furfuryl alcohol with 100% selectivity. Although formic acid can be used as a hydrogen source successfully. The optimal substrate/acid ratio was found to be 1:1, as a higher concentration of formic acid can cause catalyst decomposition. The yielded products, furfuryl alcohol and furoic acid, obtained from renewable sources, have multiple applications in the organic chemical industry, replacing or complementing similar fossil-derived products.
Aguirre, Pedro,Aranda, Braulio,López, Vicente,Moya, Sergio A.,Parra-Melipán, Sebastián,Valdebenito, Gonzalo
(2021/08/10)

Transition-metal-free decarboxylation of D-glucaric acid to furan catalyzed by SnCl4 in a biphasic system
As a useful chemical, furan can be produced from bio-based chemicals, such as furfural and furoic acid (FA). There were few reports on the preparation of furan from bio-based C6 aldaric acids. Herein, a new method was developed to produce furan from D-glucaric acid (GA) without transition metals, and nearly 80% yield of furan was produced in the water/toluene biphasic system with SnCl4 at 200 °C in 2 h. 3-Hydroxy-2-pyrone (3-HP) and FA were proved to be the key intermediates in the formation of furan from GA, and the reaction pathway was proposed to be GA→ 3-HP→ FA→ furan based on the kinetic study, model substrate reaction, and isotope labeling experiments. SnCl4 gave the highest furan yield among the common acid catalysts, and the contrast experiments suggested that H+, Cl? and Sn4+ all have promoting effect on GA conversion to furan. This method was also applicable with other C6 aldaric acids.
Duan, Yaqi,Jiang, Jun,Li, Teng,Sun, Guangyu,Wang, Yantao,Xiong, Lu,Yang, Weiran,Yu, Rui,Zheng, Boying
(2021/11/19)

Acceptorless Photocatalytic Dehydrogenation of Furfuryl Alcohol (FOL) to Furfural (FAL) and Furoic Acid (FA) over Ti3C2Tx/CdS under Visible Light
Acceptorless photocatalytic dehydrogenation is not only a promising alternative to photocatalytic water splitting for hydrogen generation but also provides a green and sustainable strategy for the synthesis of value-added organic compounds. In this work, Ti3C2Tx/CdS nanocomposites were obtained by self-assembly of hexagonal CdS in the presence of preformed Ti3C2Tx nanosheets, which serves as a photocatalyst for acceptorless dehydrogenation of biomass-derived furfuryl alcohol (FOL) to furfural (FAL) and furoic acid (FA) in neutral and alkaline medium respectively, with simultaneous generation of stoichiometric hydrogen under visible light. Ti3C2Tx MXene acts as an efficient cocatalyst for the photocatalytic dehydrogenation of FOL over CdS, with an optimum performance achieved over 0.50 wt%Ti3C2Tx/CdS nanocomposite. This study provides an economic and sustainable strategy for the simultaneous valorization of biomass-derived FOL to produce FAL and FA as well as the production of clean energy hydrogen under mild condition based on noble metal-free semiconductor-based photocatalysts.
Wang, Jiaqi,Liu, Xinyu,Li, Zhaohui
p. 2932 - 2938
(2021/08/20)

Hydrolysis of amides to carboxylic acids catalyzed by Nb2O5
Hydrolysis of amides to carboxylic acids is an industrially important reaction but is challenging due to the difficulty of cleaving the resonance stabilized amidic C-N bond. Twenty-three heterogeneous and homogenous catalysts were examined in the hydrolysis of acetamide. Results showed that Nb2O5was the most effective heterogeneous catalyst with the greatest yield of acetic acid. A series of Nb2O5catalysts calcined at various temperatures were characterized and tested in the hydrolysis of acetamide to determine the effects of crystal phase and surface properties of Nb2O5on catalytic performance. The high catalytic performance observed was attributed mainly to the facile activation of the carbonyl bond by Lewis acid sites that function even in the presence of basic inhibitors (NH3and H2O). The catalytic studies showed the synthetic advantages of the present method, such as simple operation, catalyst recyclability, additive free, solvent free, and wide substrate scope (>40 examples; up to 95% isolated yield).
Siddiki,Rashed, Md. Nurnobi,Touchy, Abeda Sultana,Jamil, Md. A. R.,Jing, Yuan,Toyao, Takashi,Maeno, Zen,Shimizu, Ken-Ichi
p. 1949 - 1960
(2021/03/26)

An efficient chromium(iii)-catalyzed aerobic oxidation of methylarenes in water for the green preparation of corresponding acids
A highly efficient method to oxidize methylarenes to their corresponding acids with a reusable Cr catalyst was developed. The reaction can be carried out in water with 1 atm oxygen and K2S2O8as cooxidants, proceeds under green and mild conditions, and is suitable for the oxidation of both electron-deficient and electron-rich methylarenes, including heteroaryl methylarenes, even at the gram level. The excellent result, together with its simplicity of operation and the ability to continuously reuse the catalyst, makes this new methodology environmentally benign and cost-effective. The generality of this methodology gives it the potential for use on an industrial scale. Differing from the accepted oxidation mechanism of toluene, GC-MS studies and DFT calculations have revealed that the key benzyl alcohol intermediate is formed under the synergetic effect of the chromium and molybdenum in the Cr catalyst, which can be further oxidized to afford benzaldehyde and finally benzoic acid.
Jiang, Feng,Liu, Shanshan,Wei, Yongge,Yan, Likai,Yu, Han,Zhao, Wenshu
supporting information
p. 12413 - 12418
(2021/09/28)

1,2-Dibutoxyethane-Promoted Oxidative Cleavage of Olefins into Carboxylic Acids Using O2 under Clean Conditions
Herein, we report the first example of an effective and green approach for the oxidative cleavage of olefins to carboxylic acids using a 1,2-dibutoxyethane/O2 system under clean conditions. This novel oxidation system also has excellent functional-group tolerance and is applicable for large-scale synthesis. The target products were prepared in good to excellent yields by a one-pot sequential transformation without an external initiator, catalyst, and additive.
Ou, Jinhua,Tan, Hong,He, Saiyu,Wang, Wei,Hu, Bonian,Yu, Gang,Liu, Kaijian
p. 14974 - 14982
(2021/10/25)

9,10-Dihydroanthracene auto-photooxidation efficiently triggered photo-catalytic oxidation of organic compounds by molecular oxygen under visible light
The development of mild and efficient process for the selective oxidation of organic compounds by molecular oxygen (O2) can be one of the key technologies for synthesizing oxygenates. This paper discloses an efficient and mild synthesis protocol for the O2-involved ethylbenzene (EB) photooxidation triggered by 910-dihydroanthracene (DHA) auto- photooxidation in acetone under visible light illumination, which can achieve 87.7 percent EB conversion and 99.5 percent acetylacetone (ACP) selectivity under ambient conditions. Also, 62.9 percent EB conversion and 96.3 percent ACP selectivity is obtained in air atmosphere. Furthermore, this protocol has a good adaptability for the photooxidation of other organic substrates such as tetrahydronaphthalene, diphenylmethane, toluene, cyclohexane, cyclohexene, alcohol, methylfuran and thioether to their corresponding oxygenates. A series of control and quenching tests, combined with EPR spectra, suggest that the photo-excited DHA can transfer its photo-electron to O2 to yield a superoxide radical anion (O2??), then DHA is preferentially oxidized to anthraquinone (AQ) by the active O2?? owing to its high reactivity. Finally, the in situ generated AQ as an active photo-catalyst can achieve the photooxidation of EB and other organic compounds by O2. The present photo-autoxidation protocol gives a good example for the O2-based selective oxidation of inert hydrocarbons under mild conditions.
Chen, Mengke,Deng, Youer,Fu, Zaihui,Hu, Wenwei,Jiang, Dabo,Liu, Yachun,Mao, Feng,Su, Anqun,Yang, Bo,Zhang, Chao
(2020/08/11)

Method for preparing organic acid by oxidative cleavage of aromatic secondary alcohol
The invention relates to a method for preparing organic acids by oxidation of aromatic secondary alcohols. With air or oxygen as an oxygen source, a copper salt and an organic ligand as catalysts, aninorganic alkali is added, and aromatic secondary alcohols are subjected to carbon-carbon bond oxidative cracking to obtain the organic acids. The method has the advantages of high oxidation efficiency and high product yield; with the use of air or oxygen as the oxygen source, the method is economical and environmentally friendly and has good application prospects.
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Paragraph 0043-0046; 0051

(2020/09/16)

Copper (II) immobilized on magnetically separable L-arginine-β-cyclodextrin ligand system as a robust and green catalyst for direct oxidation of primary alcohols and benzyl halides to acids in neat conditions
Copper (II) immobilized on L-arginine-β-cyclodextrin-functionalized magnetite nanoparticles (nano-Fe3O4@L-arginine-CD-Cu(II)) were successfully synthesized and fully characterized using FT-IR, XRD, SEM, EDX, ICP, TGA and VSM techniques. The catalytic activity of these magnetically retrievable nanoparticles was evaluated in the direct oxidation of primary alcohols and benzyl halides to acids in neat conditions that was observed to proceed well and products were obtained in good yields. In addition to showing good catalytic activity, the magnetic catalyst is easy to synthesize and can be recycled at least five times with little loss in activity.
Nejad, Masoumeh Jadidi,Salamatmanesh, Arefe,Heydari, Akbar
(2020/02/11)

Acceptorless dehydrogenative oxidation of primary alcohols to carboxylic acids and reduction of nitroarenes via hydrogen borrowing catalyzed by a novel nanomagnetic silver catalyst
A novel silver nano magnetic catalyst was devised for dehydrogenative oxidation of aromatic and aliphatic alcohols to the corresponding acid with water as the sole oxygen source and hydrogen gas as the only by-product. The designed catalytic system advantages from easy recovery of magnetic materials i.e. magnetic decantation, being economically viable and environmentally friendly. Furthermore, the catalytic reaction is able to reduce aryl nitro compounds in the absence of any reducing agent.
Yazdani, Elahe,Heydari, Akbar
supporting information

(2020/08/14)

A cyclometalated Ir(iii)-NHC complex as a recyclable catalyst for acceptorless dehydrogenation of alcohols to carboxylic acids
In this work, we have synthesized two new [C, C] cyclometalated Ir(iii)-NHC complexes, [IrCp?(C∧C:NHC)Br](1a,b), [Cp? = pentamethylcyclopentadienyl; NHC = (2-flurobenzyl)-1-(4-methoxyphenyl)-1H-imidazoline-2-ylidene (a); (2-flurobenzyl)-1-(4-formylphenyl)-1H-imidazoline-2-ylidene (b)] via intramolecular C-H bond activation. The molecular structure of complex 1a was determined by X-ray single crystal analysis. The catalytic potentials of the complexes were explored for acceptorless dehydrogenation of alcohols to carboxylic acids with concomitant hydrogen gas evolution. Under similar experimental conditions, complex 1a was found to be slightly more efficient than complex 1b. Using 0.1 mol% of complex 1a, good-to-excellent yields of carboxylic acids/carboxylates have been obtained for a wide range of alcohols, both aliphatic and aromatic, including those involving heterocycles, in a short reaction time with a low loading of catalyst. Remarkably, our method can produce benzoic acid from benzyl alcohol on a gram scale with a catalyst-to-substrate ratio as low as 1?:?5000 and exhibit a TON of 4550. Furthermore, the catalyst could be recycled at least three times without losing its activity. A mechanism has been proposed based on controlled experiments and in situ NMR study.
Borah, Dhrubajit,Das, Pankaj,Saha, Biswajit,Sarma, Bipul
p. 16866 - 16876
(2020/12/18)

Highly efficient oxidation of alcohols to carboxylic acids using a polyoxometalate-supported chromium(iii) catalyst and CO2
Direct catalytic oxidation of alcohols to carboxylic acids is very attractive, but economical catalysis systems have not yet been well established. Here, we show that a pure inorganic ligand-supported chromium compound, (NH4)3[CrMo6O18(OH)6] (simplified as CrMo6), could be used to effectively promote this type of reaction in the presence of CO2. In almost all cases, oxidation of various alcohols (aromatic and aliphatic) could be achieved under mild conditions, and the corresponding carboxylic acids can be achieved in high yield. The chromium catalyst 1 can be reused several times with little loss of activity. Mechanism study and control reactions demonstrate that the acidification proceeds via the key oxidative immediate of aldehydes.
Han, Sheng,Wang, Ying,Wei, Yongge,Wu, Zhikang,Yu, Han
p. 3150 - 3154
(2020/06/19)

Catalytic oxidation of alcohols and alkyl benzenes to carbonyls using Fe3O4?SiO2?(TEMPO)-: Co -(Chlorophyll-CoIII) as a bi-functional, self-co-oxidant nanocatalyst
Chlorophyll b was extracted from heliotropium europaeum plant, demetalated, allylated and grafted to acrylated TEMPO through a copolymerization protocol. Then, the chlorophyll monomers were coordinated to Co ions, immobilized on magnetic nanoparticles and the resulting hybrid was used as a powerful catalyst for a variety of oxidation reactions. By using the present method, oxidation of benzylic alcohols and alkyl benzenes to carbonyls was accomplished in water under aerobic conditions. Moreover, direct oxidation of alcohols to carboxylic acids was performed by adding NaOCl to the mixture. All entries were oxidized to the corresponding desired product with high to excellent yields and up to 97% selectivity. The catalyst was thoroughly characterized by CV, TGA, VSM, XRD, XPS, DLS, FE-SEM, TEM, UV-Vis, EDX, and BET analyses. The activity of the catalyst was investigated by applying various components of the catalyst to the oxidation model separately. The reasonable mechanisms are suggested based on the cooperation between the TEMPO groups and cobalt(iii) (or Co(iv)) sites on the catalyst. The catalyst could be recovered and reused for at least 7 consecutive recycles without any considerable reactivity loss. This journal is
Hamah-Ameen, Baram Ahmed,Kazemnejadi, Milad,Mahmoudi, Boshra,Rostami, Amin
p. 6600 - 6613
(2020/11/16)

Cobalt-Catalyzed Acceptorless Dehydrogenation of Alcohols to Carboxylate Salts and Hydrogen
The facile oxidation of alcohols to carboxylate salts and H2 is achieved using a simple and readily accessible cobalt pincer catalyst (NNNHtBuCoBr2). The reaction follows an acceptorless dehydrogenation pathway and displays good functional group tolerance. The amine-amide metal-ligand cooperation in cobalt catalyst is suggested to facilitate this transformation. The mechanistic studies indicate that in-situ-formed aldehydes react with a base through a Cannizzaro-type pathway, resulting in potassium hemiacetolate, which further undergoes catalytic dehydrogenation to provide the carboxylate salts and H2
Gunanathan, Chidambaram,Kishore, Jugal,Pattanaik, Sandip,Pradhan, Deepak Ranjan
supporting information

(2020/03/03)

Sequential Connection of Mutually Exclusive Catalytic Reactions by a Method Controlling the Presence of an MOF Catalyst: One-Pot Oxidation of Alcohols to Carboxylic Acids
A functionalized metal-organic framework (MOF) catalyst applied to the sequential one-pot oxidation of alcohols to carboxylic acids controls the presence of a heterogeneous catalyst. The conversion of alcohols to aldehydes was acquired through aerobic oxidation using a well-known amino-oxy radical-functionalized MOF. In the same flask, a simple filtration of the radical MOF with mild heating of the solution completely altered the reaction media, providing radical scavenger-free conditions suitable for the autoxidation of the aldehydes formed in the first step to carboxylic acids. The mutually exclusive radical-catalyzed aerobic oxidation (the first step with MOF) and radical-inhibited autoxidation (the second step without MOF) are sequentially achieved in a one-pot manner. Overall, we demonstrate a powerful and efficient method for the sequential oxidation of alcohols to carboxylic acids by employing a readily functionalizable heterogeneous MOF. In addition, our MOF in-and-out method can be utilized in an environmentally friendly way for the oxidation of alcohols to carboxylic acids of industrial and economic value with broad functional group tolerance, including 2,5-furandicarboxylic acid and 1,4-benzenedicarboxylic acid, with good yield and reusability. Furthermore, MOF-TEMPO, as an antioxidative stabilizer, prevents the undesired oxidation of aldehydes, and the perfect "recoverability"of such a reactive MOF requires a re-evaluation of the advantages of MOFs from heterogeneity in catalytic and related applications.
Kim, Seongwoo,Lee, Ha-Eun,Suh, Jong-Min,Lim, Mi Hee,Kim, Min
p. 17573 - 17582
(2020/12/22)

Furan Carboxylic Acids Production with High Productivity by Cofactor-engineered Whole-cell Biocatalysts
Furan carboxylic acids are useful chemicals in various industries. In this work, biocatalytic production of furan carboxylic acids was reported with high productivities by cofactor-engineered Escherichia coli cells. NADH oxidase (NOX) was introduced into E. coli harboring aldehyde dehydrogenases (ALDHs) to promote intracellular NAD+ regeneration, thus significantly enhancing ALDH-catalyzed oxidation. These engineered biocatalysts were capable of efficient aerobic oxidation of a variety of aromatic aldehydes. More importantly, they exhibited high substrate tolerance toward toxic furans. E. coli co-expressing vanillin dehydrogenase and NOX (E. coli_CtVDH1_NOX) enabled efficient oxidation of 250 mM of 5-hydroxymethylfurfural (HMF) to 5-hydroxymethyl-2-furancarboxylic acid (HMFCA), providing a productivity of 3.7 g/L h. With E. coli_CtVDH2_NOX as catalyst, up to 240 mM of furfural and 5-methoxymethylfurfural (MMF) could be smoothly oxidized. 2-Furoic acid (FCA, 227 mM) and 5-methoxymethyl-2-furancarboxylic acid (MMFCA, 287 mM) were produced in fed-batch synthesis, providing the productivities of 2.0 and 5.6 g/L h, respectively.
Zhang, Xue-Ying,Wang, Xin,Li, Nan-Wei,Guo, Ze-Wang,Zong, Min-Hua,Li, Ning
p. 3257 - 3264
(2020/05/25)

Catalytic Oxidative Deamination by Water with H2Liberation
Selective oxidative deamination has long been considered to be an important but challenging transformation, although it is a common critical process in the metabolism of bioactive amino compounds. Most of the synthetic methods developed so far rely on the use of stoichiometric amounts of strong and toxic oxidants. Here we present a green and efficient method for oxidative deamination, using water as the oxidant, catalyzed by a ruthenium pincer complex. This unprecedented reaction protocol liberates hydrogen gas and avoids the use of sacrificial oxidants. A wide variety of primary amines are selectively transformed to carboxylates or ketones in good to high yields. It is noteworthy that mechanistic experiments and DFT calculations indicate that in addition to serving as the oxidant, water also plays an important role in assisting the hydrogen liberation steps involved in amine dehydrogenation.
Tang, Shan,Rauch, Michael,Montag, Michael,Diskin-Posner, Yael,Ben-David, Yehoshoa,Milstein, David
supporting information
p. 20875 - 20882
(2020/12/23)

A unique pathway to platform chemicals: Aldaric acids as stable intermediates for the synthesis of furandicarboxylic acid esters
2,5-Furandicarboxylic acid (FDCA) has received attention as an emerging bio-based building block with many applications, especially in renewable polyesters. The common route to FDCA uses the unstable 5-hydroxymethylfurfural (HMF) as an intermediate. Here, we present an alternative route to FDCA and its esters using C6 aldaric acids as stable intermediates. Aldaric acids, or sugar diacids, can be obtained by the oxidation of C6 sugars or uronic acids from pectin. Subsequent dehydration of aldaric acids by solid acid catalysts in butanol produces furancarboxylates. Using silica-supported acid catalysts, over 90% yields of furancarboxylates were achieved with the selectivity to FDCA and its esters reaching 80%.
Van Strien, Nicolaas,Rautiainen, Sari,Asikainen, Martta,Thomas, David A.,Linnekoski, Juha,Niemel?, Klaus,Harlin, Ali
p. 8271 - 8277
(2020/12/28)

Light and oxygen-enabled sodium trifluoromethanesulfinate-mediated selective oxidation of C-H bonds
Visible light-induced organic reactions are important chemical transformations in organic chemistry, and their efficiency highly depends on suitable photocatalysts. However, the commonly used photocatalysts are precious transition-metal complexes and elaborate organic dyes, which hamper large-scale production due to high cost. Here, for the first time, we report a novel strategy: light and oxygen-enabled sodium trifluoromethanesulfinate-mediated selective oxidation of C-H bonds, allowing high-value-added aromatic ketones and carboxylic acids to be easily prepared in high-to-excellent yields using readily available alkyl arenes, methyl arenes and aldehydes as materials. The mechanistic investigations showed that the treatment of inexpensive and readily available sodium trifluoromethanesulfinate with oxygen under irradiation of light could in situ form a pentacoordinate sulfide intermediate as an efficient photosensitizer. The method represents a highly efficient, economical and environmentally friendly strategy, and the light and oxygen-enabled sodium trifluoromethanesulfinate photocatalytic system represents a breakthrough in photochemistry. This journal is
Fu, Hua,Liu, Can,Liu, Yong,Yang, Haijun,Zhu, Xianjin
supporting information
p. 4357 - 4363
(2020/07/14)

GREEN, COPPER-CATALYZED DISPROPORTIONATION OF AROMATIC AND HETEROAROMATIC CARBOXYLATES TO DICARBOXYLATES
The present application relates to a process for preparation of a compound of Formula (I) and Formula (IV): wherein is as described herein; and wherein and R are as described herein.
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Paragraph 0108; 0109

(2020/06/08)

Preparation of large-size, superparamagnetic, and highly magnetic Fe3O4@PDA core-shell submicrosphere-supported nano-palladium catalyst and its application to aldehyde preparation through oxidative dehydrogenation of benzyl alcohols
Large-size, superparamagnetic, and highly magnetic Fe3O4@PDA core-shell submicrospheresupported nano-palladium catalysts were prepared in this study. Dopamine was encapsulated on the surface of Fe3O4 particles via self-polymerization and then protonated to positively charge the microspheres. PdCl42- was dispersed on the surface of the microspheres by positive and negative charge attraction and then reduced to nano-palladium. With air as oxidant, the catalyst can successfully catalyze the dehydrogenation of benzyl alcohols to produce the corresponding aldehydes at 120 °C.
Guo, Haichang,Zheng, Renhua,Jiang, Huajiang,Xu, Zhenyuan,Xia, Aibao
(2019/05/24)

A Diaminopropane Diolefin Ru(0) Complex Catalyzes Hydrogenation and Dehydrogenation Reactions
New ruthenium (0) complexes with a cooperative diolefin diaminopropane (DAP) or the dehydrogenated iminopropenamide ligand (IPA) were synthesized for comparison with their diaminoethane (DAE)/ diazadiene (DAD) ruthenium analogues. These DAP/IPA complexes are efficient catalysts in dehydrogenation reactions of alkaline aqueous methanol which proceeds under mild conditions (T=70 °C) and of higher alcohols, forming the corresponding carbonate and carboxylates, respectively. The scope of the reaction includes an example of a 1,2-diol as model for biomass derived alcohols. Their catalytic applications are extended to the atom-efficient dehydrogenative coupling of alcohols and amines to amides. The reaction proceeds without any additives and is applicable to the synthesis of formamides from methanol. Moreover, DAP/IPA complexes catalyze the hydrogenation of a series of esters, lactone, ketone, activated olefin, aldehyde and imine substrates. The diaminopropane Ru catalyst exhibits higher activity compared to the dehydrogenated β-ketiminate (IPA) and previously studied DAD/DAE based catalysts. We present studies on their stoichiometric reactivity with relevance to their possible catalytic mechanisms and the isolation and full characterization of key reaction intermediates.
Casas, Fernando,Trincado, Monica,Rodriguez-Lugo, Rafael,Baneerje, Dipshikha,Grützmacher, Hansj?rg
p. 5241 - 5251
(2019/11/16)

Dehydrogenation of Alcohols to Carboxylic Acid Catalyzed by in Situ-Generated Facial Ruthenium- CPP Complex
A selective catalytic system for the dehydrogenation of primary alcohols to carboxylic acids using a facial ruthenium complex generated in situ from the [Ru(COD)Cl2]n and a hybrid N-heterocyclic carbene (NHC)-phosphine-phosphine ligand (CPP) has been first reported. The facial coordination model was unveiled by NMR analysis of the reaction mixture. Such a fac-ruthenium catalyst system exhibited high catalytic activity and stability, and a high turnover number of 20 000 could be achieved with catalyst loading as low as 0.002 mol %. The exceedingly high catalyst stability was tentatively attributed to both the anchoring role of NHC and the hemi-lability of phosphines. The catalytic system also features a wide substrate scope. In particular, the facial coordination of CPP ligands was found to be beneficial for sterically hindered alcohols, and ortho-substituted benzylic alcohols and bulky adamantanyl methanol as well as cholesterol were all found to be viable dehydrogenation substrates.
Liu, Hui-Min,Jian, Lei,Li, Chao,Zhang, Chun-Chun,Fu, Hai-Yan,Zheng, Xue-Li,Chen, Hua,Li, Rui-Xiang
p. 9151 - 9160
(2019/08/12)

Defect engineering of nickel hydroxide nanosheets by Ostwald ripening for enhanced selective electrocatalytic alcohol oxidation
Selective electrocatalytic oxidation (ECO) of alcohols to aldehydes or acids is an environmentally friendly and economical method in modern industries. Herein, tunable holes and vacancies in nickel hydroxide (h-Ni(OH)2) by the Ostwald ripening process are successfully fabricated, and the as-prepared electrocatalysts are used for the selective ECO of alcohols into acids or aldehydes with excellent electrocatalytic activity and stability, where a selectivity above 92% to benzoic acid with a benzyl alcohol conversion of 99% on 1.0 h-Ni(OH)2 was obtained, while a selectivity of >94% to benzaldehyde with a conversion of >90% could also be achieved once the 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) radical was employed. A paired electrolysis system is employed using 1.0 h-Ni(OH)2 and 1.0 PtO2/h-Ni(OH)2 as electrocatalysts at the anode and cathode, respectively, to simultaneously achieve the selective ECO of benzyl alcohol and H2 production, resulting in a high faradaic efficiency of 192.9%. The excellent ECO activity is mainly due to the abundance of holes and vacancies which facilitate the diffusion rate of the reaction species, adjust the electronic structure and surface properties of h-Ni(OH)2, and change the charge density around benzyl alcohol, thereby enhancing the adsorption energy of the alcohol. This study introduces a new avenue for the understanding and future design of advanced defect-based electrocatalysts for electrosynthesis and energy conversion.
Chen, Xianlang,Zhong, Xing,Yuan, Bowen,Li, Suiqin,Gu, Yongbing,Zhang, Qiaoqiao,Zhuang, Guilin,Li, Xiaonian,Deng, Shengwei,Wang, Jian-Guo
p. 578 - 588
(2019/02/14)

One-Pot Enzyme Cascade for Controlled Synthesis of Furancarboxylic Acids from 5-Hydroxymethylfurfural by H2O2 Internal Recycling
Furancarboxylic acids are promising biobased building blocks in pharmaceutical and polymer industries. In this work, dual-enzyme cascade systems composed of galactose oxidase (GOase) and alcohol dehydrogenases (ADHs) are constructed for controlled synthesis of 5-formyl-2-furancarboxylic acid (FFCA) and 2,5-furandicarboxylic acid (FDCA) from 5-hydroxymethylfurfural (HMF), based on the catalytic promiscuity of ADHs. The byproduct H2O2, which is produced in GOase-catalyzed oxidation of HMF to 2,5-diformylfuran (DFF), is used for horseradish peroxidase (HRP)-mediated regeneration of the oxidized nicotinamide cofactors for subsequent oxidation of DFF promoted by an ADH, thus implementing H2O2 internal recycling. The desired products FFCA and FDCA are obtained with yields of more than 95 %.
Jia, Hao-Yu,Zong, Min-Hua,Zheng, Gao-Wei,Li, Ning
p. 4764 - 4768
(2019/11/05)

Preparing method of 2-furoic acid
The invention discloses a preparing method of 2-furoic acid. The preparing method comprises the steps of adjusting a solution containing 2-acetylfuran and a halogen source to be neutral in pH to obtain a liquid-phase precursor; adjusting the liquid-phase precursor to be acid in pH to obtain the 2-furoic acid. The method is simple and efficient, the flow process is short, few by-products are produced, and the 2-furoic acid prepared by means of the method is high in purity, and can meet the requirement for serving as chemical raw materials and medical intermediate raw materials.
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Paragraph 0047-0064

(2019/07/10)

Method for preparing furoic acid through furfural oxidation
The invention provides a method for preparing furoic acid through furfural oxidation. The method comprises the following steps: 1) taking sodium hydroxide and distilled water in an amount of 1-1.3 times that of the mass of furfural to prepare alkali liquor 1; 2) taking sodium hydroxide and distilled water in an amount of 2-4 times that of the mass of furfural to prepare alkali liquor 2; 3) addinga compound nanocrystalline metal oxide catalyst in an amount of 0.3-0.5 time that of the mass of furfural and the alkali liquor 1 prepared in the step 1) into a reaction bottle; and 4) controlling thetemperature to be 35-45 DEG C, introducing air into the reaction bottle, dropping the alkali liquor 2 and the furfural, and filtering to remove the catalyst after the reaction is completed; and performing a subsequent step to obtain wet furoic acid, performing vacuum drying, and controlling the moisture content to be less than 0.1%, thereby obtaining the white or faint yellow crystal powder furoic acid. According to the technical scheme of the invention, industrialization is easily realized, the yield can reach 93% or higher, and the method is capable of purifying the reaction impurity furfuryl alcohol and has a certain economic advantages.
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Paragraph 0020-0023

(2019/04/06)

Selective synthesis of 2-furoic acid and 5-hydroxymethyl-2-furancarboxylic acid from bio-based furans by recombinant Escherichia coli cells
Upgradation of bio-based furans into chemicals and biofuels has received great interest recently. In this work, we reported selective synthesis of furan carboxylic acids from the corresponding aldehydes by recombinant Escherichia coli cells expressing 3-succinoylsemialdehyde-pyridine dehydrogenase (SAPDH) from Comamonas testosteroni SC1588. The effects of induction and reaction conditions on whole-cell catalytic oxidation of furfural (FF) were studied. High temperature induction resulted in decreased activities of recombinant cells, likely due to improper protein folding. Nonetheless, recombinant cells induced under high temperature enable the byproduct furfuryl alcohol to be faster re-oxidized into 2-furoic acid (FCA) than those induced under low temperature. So the yield and selectivity of FCA were improved significantly by using high temperature induction, at expense of slightly longer reaction periods. The activities of recombinant cells highly depended on pH. The tolerant levels of this recombinant strain toward FF and 5-hydroxymethylfurfural (HMF) were approximately 100 mM. FCA and 5-hydroxymethyl-2-furancarboxylic acid (HMFCA) were obtained with the yields of 95–98%. FCA of up to 147 mM was produced by a fed-batch strategy, in a quantitative yield. In addition, most aromatic aldehydes tested were transformed into the target carboxylic acids by this biocatalytic method, with the yields up to 100%.
Shi, Sai-Sai,Zhang, Xue-Ying,Zong, Min-Hua,Wang, Chuan-Fu,Li, Ning
p. 68 - 74
(2019/03/14)

Synthesis of 2, 5 furan-phthalic acid (by machine translation)
The invention relates to a method for synthesizing 2, 5 furan-phthalic acid, the method first preparing inorganic oxide supported copper oxide, at a relatively low temperature oxidation and furfural is furoic; secondly, preparing inorganic oxide supported carbonate; finally the inorganic oxide supported carbonate, furoic, carbon dioxide are introduced into the high-pressure reactor in synthesis 2, 5 furan phthalic acid, through this method, the conversion of the furfural can reach 100%, 2, 5 furan dicarboxylic acid of the yield can reach 80% or more. (by machine translation)
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Paragraph 0021; 0024; 0025; 0034; 0043; 0052; 0062

(2019/05/08)

Synthesis method of dialkyl 2,5-furan dicarboxylate
The invention belongs to the technical field of five-membered ring compounds, which are not condensed with other rings and contain one oxygen atom taken as the only heterocyclic atom, and specificallyrelates to a synthesis method of dialkyl 2,5-furan dicarboxylate. The synthesis method comprises following steps: step A, taking spinel type copper aluminate as a catalyst to oxidize furfural to obtain furoic acid; and step B, sequentially introducing furoic acid, carbonate, and alcohols into a high pressure reactor, closing the reactor, blowing the reactor by nitrogen for three times, filling carbon dioxide into the reactor until the pressure reaches 1 to 4 MPa, and carrying out reactions for 6 to 24 hours at a reaction temperature of 200 to 240 DEG C. The adopted raw materials are abundantand can be obtained massively; the reaction conditions are mild, the yield of the target product can reach 90-95%; target product selectivity can reach 100%; the reaction time is short, the catalyst and the reaction system are easy to separate, the catalyst can be repeatedly used, and the preparation method can be applied to industrial production.
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Page/Page column 5-7

(2019/07/04)

Microwave-assisted Cannizzaro reaction—Optimisation of reaction conditions
The microwave-assisted Cannizzaro reaction was studied in order to develop fully reproducible synthetic protocols for transformation of aldehydes to carboxylic acid and alcohols. Optimised were the following process parameters: power, temperature, and time. Aromatic, heteroaromatic and aliphatic aldehydes were used in the studies. It was found that furfural, thiophene-2-carbaldehyde, pyridinecarboxaldehyde and aromatic aldehydes react under mild conditions, while 1-methyl-pyrrole-2-carboxaldehyde derivatives and aliphatic aldehydes require more drastic reaction conditions and a longer exposure time to microwave radiation.
Janczewski, ?ukasz,Walczak, Ma?gorzata,Fr?czyk, Justyna,Kamiński, Zbigniew J.,Kolesińska, Beata
supporting information
p. 3290 - 3300
(2019/11/05)

Copper Catalyzed Oxidative C-C Bond Cleavage of 1,2-Diketones: A Divergent Approach to 1,8-Naphthalimides, Biphenyl-2,2′-dicarboxamides, and N-Heterocyclic Amides
We report here a simple and efficient copper catalyzed oxidative C-C bond cleavage of stable aromatic cyclic-fused and acyclic 1,2-diketones to deliver amides and imides in high yields. This newly developed protocol provides an excellent tool to transform structurally different 1,2-diketones into different products under the same reaction conditions. The key synthetic features of this methodology are the formation of 1,8-naphthalimides and biphenyl-2,2′-dicarboxamide motifs in high yields. The fluorescent studies of 1,8-naphthalimide derivatives were also carried out in order to show the potential application of these scaffolds.
Sakhare, Priyanka R.,Subramanian, Parthasarathi,Kaliappan, Krishna P.
p. 2112 - 2125
(2019/02/14)