- RHODIUM(III) COMPLEXES WITH O-ALKYL-S-ALKYL THIOCARBONATES AS CATALYSTS FOR THE HOMOGENEOUS HYDROGENATION OF UNSATURATED COMPOUNDS
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Catalytic activity was found for Rh3+ complexes with O-alkyl-S-alkyl thiocarbonates in the homogeneous hydrogenation of unsaturated compounds.Cyclic voltamperometry was used to detect the formation of rhodium hydride intermediates during the hydrogenation of alkenes in the presence of these complexes.
- Maistrenko, V. N.,Rusakov, I. A.,Bondareva, S. O.,Murinov, Yu. I.,Tolstikov, G. A.
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- Catalytic oxidation of furan and hydrofuran compounds. 7. Production of 2(5H)-furanone by oxidation of furfural with hydrogen peroxide and some of its transformations in aqueous solutions
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Data on the synthesis of 2(5H)-furanone by the oxidation of furfural with aqueous hydrogen peroxide under the conditions of autocatalysis by the accumulating acids and also in the presence of catalytic amounts of Cr(VI) and Mo(VI) compounds are presented.
- Badovskaya,Latashko,Poskonin,Grunskaya,Tyukhteneva,Rudakova,Pestunova,Sarkisyan
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- Boosting one-step conversion of cyclohexane to adipic acid by NO2 and VPO composite catalysts
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We demonstrate VPO composites as efficient catalysts for highly selective oxidation of cyclohexane to adipic acid with NO2. In particular, the Ni-Al-VPO composite catalyst exhibits the striking conversion of cyclohexane (60.6%) and exceptionally high selectivity towards adipic acid (85.0%). Moreover, N2O is an environmentally harmful gas, and its yield in the present process is only 0.03 t/t adipic acid, which is far below that obtained using the industrial method (0.3 t/t adipic acid). This work provides a new strategy for the one-step synthesis of dicarboxylic acids from cycloalkanes.
- Jian, Jian,You, Kuiyi,Duan, Xuezhi,Gao, Hongxu,Luo, Qing,Deng, Renjie,Liu, Pingle,Ai, Qiuhong,Luo, He'an
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- Conjugated microporous polymers as a visible light driven platform for photo-redox conversion of biomass derived chemicals
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Photocatalytic conversion of biomass derived chemicals to valuable products is a highly sustainable process. Herein we report the photocatalytic hydrogenation of maleic acid to succinic acid and oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran using the same conjugated porous polymers (CMPs). The CMPs were constructed from 2,4,6-(tri-2-thienyl)-1,3,5-triazine as the knots and different benzene derivatives as linkers, and their morphologies, redox potentials, charge separation efficiency, and the consequent photocatalytic performance have been controlled. As a result, the CMP with benzene as the linker features the highest photocatalytic activities with production rates of 4.66 mmol g?1h?1for succinic acid and 0.53 mmol g?1h?1for 2,5-diformylfuran, respectively. Most importantly, high photocatalytic activity has also been achieved under natural sunlight irradiation, implying its feasibility as an efficient photocatalytic platform for solar-to-chemical energy conversion.
- Chen, Bo,Chen, Lang,Chen, Shanyong,Jin, Yongdong,Kang, Jinyang,Ma, Lijian,Xia, Chuanqin,Yan, Hongjian,Yan, Zijun
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- Metal Sub-nanoclusters Confined within Hierarchical Porous Carbons with High Oxidation Activity
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Metal sub-nanoclusters (SNCs) have shown great promise for a variety of catalytic reactions. However, the fabrication of stable metal SNCs simultaneously with high dispersion and high metal contents remains a challenge. Herein, we report a novel and versatile strategy for the synthesis of various bimetal SNCs stabilized within hierarchical porous carbons (HPC). This facile synthesis only involves the self-assembly of a metal-organic framework (MOF) as the precursor, a molten salt assisted pyrolysis process and the final metal replacement. The metal SNCs (mostly less than 0.8 nm) derived from the metal nodes of the MOF are exclusively confined and homogeneously dispersed throughout the organic ligands derived HPC at high loadings (up to 11.2 wt %). The obtained Cu-Pd@HPC composite exhibits superior catalytic activity and recycling durability in the selective transformation of furfural to maleic acid, achieving 97.8 % yield of maleic acid with a TOF value as high as 20.1 h?1 under mild conditions. DFT calculations reveal that the introduction of Pd shifts the partial density of states of Cu toward the Fermi level, leading to stronger chemisorption of furfural to enhance the catalytic activity.
- Zhao, Xin,Kong, Xiangpeng,Wang, Fengliang,Fang, Ruiqi,Li, Yingwei
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- Highly active and selective nickel-platinum catalyst for the low temperature hydrogenation of maleic anhydride to succinic anhydride and synthesis of succinic acid at 40 °c
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PtNi bimetallic and Ni monometallic catalysts supported on HY-Al 2O3, HX-Al2O3, ZSM-5-Al 2O3, USY-Al2O3, Beta-Al 2O3 and Al2O3 were prepared and evaluated for the hydrogenation of maleic anhydride in the temperature range of 40-150 °C. Results from flow reactor studies showed that supports strongly affected the catalytic properties of different bimetallic and monometallic catalysts. The results showed that the HY-Al2O3 support exhibited the highest activity and selectivity. Using NiPt/Al2O 3-HY catalyst and performing the reaction, it was possible to carry out the lowest reaction temperature ever carried at 100% conversion. Adding a small amount of Pt (0.5) to the Ni (5%)/Al2O3-HY catalyst that is effective for increasing the selectivity and activity. We also found that PtNi is an efficient catalyst for the one-pot conversion of maleic acid into succinic acid with 100% conversion at 40 °C. Graphical Abstract: Hydrogenation activity was found to correlate to the extent of PtNi bimetallic bond formation, as characterized by the analysis of XRD and TPR.[Figure not available: see fulltext.]
- Li, Jie,Tian, Wei-Ping,Shi, Li
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- The contribution to kappa number from hexeneuronic acid groups in pulp xylan
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The kappa number of chemical pulps is widely used both in mill operation and in laboratory work as a measure of the degree of delignification in pulping, oxygen delignification, and prebleaching. Recently, it has been shown that the kappa number reflects not only lignin but also carbohydrate structures sensitive to oxidation by permanganate, notably hexeneuronic acid groups linked to xylan. In the present work, the kappa number units originating from hexeneuronic acid groups calculated on a molar basis have been determined in two different ways, viz. by permanganate oxidation of model compounds and by selective elimination of hexeneuronic acid groups from a series of kraft pulps. The results are in good agreement with each other and demonstrate that 10 μmol of hexeneuronic acid correspond to 0.84-0.86 kappa units. From kappa number determinations combined with hydrolysis of the pulp with mercuric acetate, it is possible to calculate the amount of hexeneuronic acid groups present in a pulp.
- Li, Jiebing,Gellerstedt, Goeran
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- Near infrared activation of an anticancer PtIV complex by Tm-doped upconversion nanoparticles
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The PtIV complex cis,cis,trans-[Pt(NH3)2(Cl)2(O2CCH2CH2CO2H)2] is photoactivated by near infrared light (980 nm) using NaYF4:Yb3+/Tm3+@NaYF4 core-shell upconversion nanoparticles. Coupling of this cisplatin precursor with the biocompatible PEGylated phospholipid DSPE-PEG(2000)-NH2 affords a valuable approach to decorate the surface of the nanoparticles, providing novel photoactivatable nanomaterials capable of releasing PtII species upon NIR light excitation. This journal is
- Ruggiero, Emmanuel,Hernández-Gil, Javier,Mareque-Rivas, Juan C.,Salassa, Luca
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- Encapsulation of Pt(IV) prodrugs within a Pt(II) cage for drug delivery
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This report presents a novel strategy that facilitates delivery of multiple, specific payloads of Pt(IV) prodrugs using a well-defined supramolecular system. This delivery system comprises a hexanuclear Pt(II) cage that can host four Pt(IV) prodrug guest molecules. Relying on host-guest interactions between adamantyl units tethered to the Pt(IV) molecules and the cage, four prodrugs could be encapsulated within one cage. This host-guest complex, exhibiting a diameter of about 3 nm, has been characterized by detailed NMR spectroscopic measurements. Owing to the high positive charge, this nanostructure exhibits high cellular uptake. Upon entering cells and reacting with biological reductants such as ascorbic acid, the host-guest complex releases cisplatin, which leads to cell cycle arrest and apoptosis. The fully assembled complex displays cytotoxicity comparable to that of cisplatin against a panel of human cancer cell lines, whereas the cage or the Pt(IV) guest alone exhibit lower cytotoxicity. These findings indicate the potential of utilising well-defined supramolecular constructs for the delivery of prodrug molecules.
- Zheng, Yao-Rong,Suntharalingam, Kogularamanan,Johnstone, Timothy C.,Lippard, Stephen J.
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- Reducing Agent-Mediated Nonenzymatic Conversion of 2-Oxoglutarate to Succinate: Implications for Oxygenase Assays
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l-Ascorbate (l-Asc) is often added to assays with isolated FeII- and 2-oxoglutarate (2OG)-dependent oxygenases to enhance activity. l-Asc is proposed to be important in catalysis by some 2OG oxygenases in vivo. We report observations on the nonenzymatic conversion of 2OG to succinate, which is mediated by hydrogen peroxide generated by the reaction of l-Asc and dioxygen. Slow nonenzymatic oxidation of 2OG to succinate occurs with some, but not all, other reducing agents commonly used in 2OG oxygenase assays. We intend these observations will help in the robust assignment of substrates and inhibitors for 2OG oxygenases.
- Khan, Amjad,Schofield, Christopher J.,Claridge, Timothy D. W.
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- Hydroxylamine as an oxygen nucleophile. Chemical evidence from its reaction with a phosphate triester
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The reaction of hydroxylamine with 2,4-dinitrophenyl diethyl phosphate gives the O-phosphorylated product, which is rapidly converted to hydrazine and nitrogen gas in the presence of the excess of hydroxylamine. The Royal Society of Chemistry.
- Kirby, Anthony J.,Souza, Bruno S.,Medeiros, Michelle,Priebe, Jacks P.,Manfredi, Alex M.,Nome, Faruk
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- The effect of Br- and alkali in enhancing the oxidation of furfural to maleic acid with hydrogen peroxide
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This study was focused on investigating a novel catalytic system for the selective conversion of furfural to maleic acid (MA) in an aqueous system with hydrogen peroxide as an oxidant. A series of experiments that study the impacts of catalyst species, furfural concentration, catalyst dosage, reaction temperature, residue time, hydrogen peroxide concentration, excess water content, and solvent types on the oxidation of furfural to MA was carried out. The results showed that the co-existence of Br- and alkali sites might play a vital role in furfural oxidation, which could improve the MA yield remarkably. Under 90 °C for 3 h, 72.4 % MA yield was obtained with KOH and KBr as co-catalyst in an aqueous phase. Moreover, a possible reaction pathway of furfural oxidation was proposed on the basis of our reaction system.
- Yang, Tao,Li, Wenzhi,Ogunbiyi, Ajibola T.
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- Characterization and reactivity of Mn-Ce-O composites for catalytic ozonation of antipyrine
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Mn-Ce-O composites were prepared by a redox-precipitation method and used as a catalyst for ozonation of antipyrine (AP) in aqueous solution. The phase composition, surface area and electron transfer ability of the products are dependent on the molar ratio of precursors. Mn-Ce-O(8/2) exhibited the highest activity for the degradation and mineralization of AP with ozone, which can be attributed to its high electron transfer ability. The decomposition of ozone into .OH can be accelerated through the electron transfer between ozone and catalyst. The refractory intermediates in ozonation and catalytic ozonation were identified and the catalytic performances of Mn-Ce-O(8/2) for these intermediates were also investigated. The hydroxyl radical reaction played an important role in the degradation of the refractory intermediates, and the contribution of surface reactions was strengthened with decreasing pH. A possible mechanism for the catalytic ozonation of AP was proposed.
- Xing, Shengtao,Lu, Xiaoyang,Ren, Limei,Ma, Zichuan
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- Photoelectroreduction of Building-Block Chemicals
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Conventional photoelectrochemical cells utilize solar energy to drive the chemical conversion of water or CO2 into useful chemical fuels. Such processes are confronted with general challenges, including the low intrinsic activities and inconvenient storage and transportation of their gaseous products. A photoelectrochemical approach is proposed to drive the reductive production of industrial building-block chemicals and demonstrate that succinic acid and glyoxylic acid can be readily synthesized on Si nanowire array photocathodes free of any cocatalyst and at room temperature. These photocathodes exhibit a positive onset potential, large saturation photocurrent density, high reaction selectivity, and excellent operation durability. They capitalize on the large photovoltage generated from the semiconductor/electrolyte junction to partially offset the required external bias, and thereby make this photoelectrosynthetic approach significantly more sustainable compared to traditional electrosynthesis.
- Chen, Fengjiao,Cui, Wei,Zhang, Jie,Wang, Yeyun,Zhou, Junhua,Hu, Yongpan,Li, Yanguang,Lee, Shuit-Tong
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- A rationale of the BaeyerVilliger oxidation of cyclohexanone to ε-caprolactone with hydrogen peroxide: Unprecedented evidence for a radical mechanism controlling reactivity
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We demonstrate, for the first time, in the BaeyerVilliger oxidation of cyclohexanone with aqueous hydrogen peroxide under conditions aimed at obtaining ε-caprolactone, that a thermally activated radical reaction leads to the concurrent formation of adipic acid, even when a stoichiometric amount of the oxidant is used. In fact, ε-caprolactone is the primary reaction product, but it is more reactive than cyclohexanone, and quickly undergoes consecutive transformations. When titanium silicalite-1 (TS-1) is used as a catalyst, the high concentration of hydroxy radicals within its pores accelerates the reaction rates, and the consecutive formation of adipic acid (and of lighter diacids as well) becomes largely kinetically preferred. The proper choice of the solvent, which also may act as a radical scavenger, both without catalyst and with TS-1, is a powerful tool for controlling the rates of the various reactions involved.
- Cavani, Fabrizio,Raabova, Katerina,Bigi, Franca,Quarantelli, Carla
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- Unusual conversion of 5-hydroxy-2(5H)-furanone in aqueous solution
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The conversion of 5-hydroxy-2(5H)-furanone into succinic acid in aqueous solution has been detected experimentally for the first time, indicating the possibility of forming and hydrolyzing its previously unknown tautomeric forms. The accelerating effect of increased pH values and temperature on the reaction has been established. A scheme is proposed to form succinic acid from 5-hydroxy-2(5H)-furanone.
- Poskonin,Badovskaya
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- The Effect of pH on the Reactions of Catalytically Important RhI Complexes in Aqueous Solution: Reaction of [RhCl(tppms)3] and trans-[RhCl(CO)(tppms)2] with Hydrogen (TPPMS = mono-sulfonated triphenylphosphine)
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Hydrolysis and hydrogenation of [RhCl(tppms)3] (1) and trans-[RhCl(CO)(tppms)2] (2) was studied in aqueous solutions in a wide pH range (2 pH 11) in the presence of excess TPPMS (3-diphenylphosphinyl-benzenesulfonic acid sodium salt). In acidic solutions hydrogenation of 1 yields a mixture of cis-mer- and cis-fac-[RhClH2(tppms)3] (3a,b) while in strongly basic solutions [RhH(H2O)(tppms)3] (4) is obtained, the midpoint of the equilibrium between these hydride species being at pH 8.2. The paper gives the first successful 1H and 31P NMR spectroscopic characterization of a water soluble rhodium(I)-monohydride (4) bearing only monodentate phosphine ligands. Hydrolysis of 2 is negligible below pH 9 and its hydrogenation results in formation of [Rh(CO)H(tppms)3] (5), which is an analogue to the well known and industrially used hydroformylation catalyst [Rh(CO)H(tppts)3] (6) (TPPTS = 3,3',3"-phosphinetriyltris(benzenesulfonic acid) trisodium salt). It was shown by pH-potentiometric measurements that formation of 5 is strongly pH dependent in the pH5 - 9 range; this gives an explanation for the observed but previously unexplained pH dependence of several hydroformylation reactions. Conversely, the effect of pH on the rate of hydrogenation of maleic and fumaric acid catalyzed by 1 in the 2 pH 7 range can be adequately described by considering solely the changes in the ionization state of these substrates. All these results warrant the use of buffered (pH-controlled) solutions for aqueous organometallic catalysis.
- Joo, Ferenc,Kovacs, Jozsef,Benyei, Attila Cs.,Nadasdi, Levente,Laurenczy, Gabor
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- Selective C?O Bond Cleavage of Bio-Based Organic Acids over Palladium Promoted MoOx/TiO2
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Hydrodeoxygenation chemistries play a key role in the upgrading of biomass-derived feedstocks. Among these, the removal of targeted hydroxyl groups through selective C?O bond cleavage from molecules containing multiple functionalities over heterogeneous catalysts has shown to be a challenge. Herein, we report a highly selective and stable heterogeneous catalyst for hydrodeoxygenation of tartaric acid to succinic acid. The catalyst consists of reduced Mo5+ centers promoted by palladium, which facilitate selective C?O bond cleavage, while leaving intact carboxylic acid end groups. Stable catalytic performance over multiple cycles is demonstrated. This catalytic system opens up opportunities for selective processing of biomass-derived sugar acids with a high degree of chemical functionality.
- Albarracín-Suazo, Sandra,Nacy, Ayad,Nikolla, Eranda,Pagán-Torres, Yomaira J.,Roberts, Charles A.,Ruiz-Valentín, Génesis,de Lima e Freitas, Lucas Freitas
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- Selective oxidation of furfural in a bi-phasic system with homogeneous acid catalyst
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The selective catalytic oxidation of furfural to 2(5H)-furanone, succinic acid (SA) and maleic acid (MA) was studied. Under optimized conditions, furfural was oxidized to 2(5H)-furanone with a yield of 60–62% in an aqueous/organic bi-phasic system using 1,2-dichloroethane or ethyl acetate as the solvent and formic acid as the catalyst, while the total yield of SA and MA was 15–20%. Compared with other homogeneous and heterogeneous acid catalysts, formic acid gave a much higher selectivity to 2(5H)-furanone because it reacted with hydrogen peroxide to generate performic acid that had a strong oxidizing nature and good solubility in both the aqueous and organic phases. The solvent had a significant influence on the product distribution. A simplified reaction network was established to quantitatively analyze the solvent effect based on the reaction rate constants. In the homogeneous system, the yield of 2(5H)-furanone decreased while the yield of SA increased with an increasing dielectric constant of the solvent. The formic acid/furfural molar ratio, reaction temperature and furfural concentration were optimized for the selective oxidation of furfural to 2(5H)-furanone in the bi-phasic reaction system.
- Li, Xiaodan,Lan, Xiaocheng,Wang, Tiefeng
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- Catalytic oxidation of furan and hydrofuran compounds 8. Synthesis of 5-ethoxycarbonyl-4-hydroxy-3-oxo-2(3H)-furanone by the oxidation of furfural in the system aqueous H2O2-VOSO4-ethanol
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The special features of the oxidation of furfural by aqueous hydrogen peroxide in the presence of vanadyl sulfate and ethanol has been studied for the first time. It has been established that this reaction proceeds with the formation of previously unknown
- Poskonin
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- Reactions of α-carbanions of lithium acylates with N,N-diethyl-N-chloro- and N,N-diethyl-N-bromoamines
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The interaction of α-carbanions of lithium acylates (prepared via metalation of acetic, butyric, or isobutyric acid with lithium diisopropylamide in tetrahydrofuran under argon atmosphere) with N,N-diethyl-N-chloro- or N,N-diethyl-N-bromoamine has resulte
- Zorin,Zainashev,Zorin
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- Effects of hydrophobicity of diffusion layer on the electroreduction of biomass derivatives in polymer electrolyte membrane reactors
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For the first time, the hydrophobicity design of a diffusion layer based on the volatility of hydrogenation reactants in aqueous solutions is reported. The hydrophobicity of the diffusion layer greatly influences the hydrogenation performance of two model biomass derivatives, namely, butanone and maleic acid, in polymer electrolyte membrane reactors operated at atmospheric pressure. Hydrophobic carbon paper repels aqueous solutions, but highly volatile butanone can permeate in vapor form and achieve a high hydrogenation rate, whereas, for nonvolatile maleic acid, great mass transfer resistance prevents hydrogenation. With a hydrophilic stainless-steel welded mesh diffusion layer, aqueous solutions of both butanone and maleic acid permeate in liquid form. Hydrogenation of maleic acid reaches a similar level as that of butanone. The maximum reaction rate is 340 nmolcm-2 s-1 for both hydrogenation systems and the current efficiency reaches 70%. These results are better than those reported in the literature.
- Chen, Wei,He, Gaohong,Ge, Feilong,Xiao, Wu,Benziger, Jay,Wu, Xuemei
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- Catalytic oxidation of furan and hydrofuran compounds. 4. Oxidation of furfural by hydrogen peroxide in the presence of sodium molybdate
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The oxidation of furfural by an aqueous solution of hydrogen peroxide in the presence of sodium molybdate was studied for the first time. Its final products are 2(5H)-furanone and also tartaric, malic, and succinic acids. The process takes place through the formation of peroxide and carbonyl compounds. Kinetic curves for the consumption of the reagents and the accumulation of the reaction products were obtained. In direction oxidation in this system differs substantially from the previously studied reactions of furfural with an aqueous solution of hydrogen peroxide without a catalyst and in the presence of selenium and vanadium compounds. 1999 Kluwer Academic/Plenum Publishers.
- Grunskaya,Badovskaya,Poskonin,Yakuba
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- Cancer-associated 2-oxoglutarate analogues modify histone methylation by inhibiting histone lysine demethylases
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Histone lysine demethylases (KDMs) are 2-oxoglutarate-dependent dioxygenases (2-OGDDs) that regulate gene expression by altering chromatin structure. Their dysregulation has been associated with many cancers. We set out to study the catalytic and inhibito
- Laukka, Tuomas,Myllykoski, Matti,Looper, Ryan E.,Koivunen, Peppi
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- Aqueous-phase catalytic oxidation of furfural with H2O2: High yield of maleic acid by using titanium silicalite-1
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This investigation explores the selective liquid-phase oxidation of furfural to maleic acid (MA) using hydrogen peroxide as an oxidant and titanium silicalite (TS-1) as a catalyst. The effect of temperature and of the concentration of H2O2, furfural and catalyst on the MA yield was studied. The highest yield, 78 mol%, was obtained under the following reaction conditions: 4.6 wt% of furfural, 4.6 wt% of catalyst, a H2O2/furfural mol ratio of 7.5, corresponding to 12.3 wt% of H2O2, 323 K and 24 hours of reaction. To reduce the amount of H2O2 employed, a two-step sequence of reactions was conducted using TS-1 and Amberlyst 70 consecutively as catalysts in the first and second steps, respectively. In this case, a H2O2/furfural mol ratio = 4.4 was required, which is quite close to the stoichiometric ratio (3.0), and a maleic acid yield close to 80% was obtained under 4.6 wt% of furfural, 4.6 wt% of catalyst and 28 h of reaction at 323 K; after 52 h of reaction, the MA yield reached 92%. Fresh and used catalysts were characterised by X-ray diffraction (XRD), Raman spectroscopy, total reflection X-ray fluorescence (TXRF), X-ray photoelectron spectroscopy (XPS), N2 adsorption-desorption isotherms and thermogravimetric analysis. Ti was largely incorporated within the silicalite framework, but the presence of some TiO2 anatase was also confirmed. Ti leaching was observed, especially during the first run but became much less important in successive cycles. Leaching affects both anatase and Ti species within the silicalite framework. Notwithstanding the leaching, when using pure furfural, TS-1 could be reused for six runs without noticeable deactivation, whereas when using furfural directly derived from biomass, weak but visible deactivation occurred upon reutilisation; this deterioration must be related to the presence of some organic products other than furfural.
- Alonso-Fagndez,Agirrezabal-Telleria,Arias,Fierro,Mariscal,Granados, M. Lpez
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- Levulinic acid upgrade to succinic acid with hydrogen peroxide
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Levulinic acid is produced from the acidic aqueous degradation of 5-hydroxymethylfurfural, with potential applications in bio-value added chemicals synthesis. Here, we report for the first time, the Baeyer-Villiger oxidation of levulinic acid to succinic acid, with hydrogen peroxide and tungstic acid at mild conditions and without any organic solvent. We investigated the effects of time, amount of reagent-to-catalyst molar ratio and H2O2-to-levulinic acid molar ratio. The maximum succinic acid selectivity was 75% with a levulinic acid conversion as high as 48%, after 6 h at 90 °C. We propose a reaction mechanism based on results obtained from the reactivity of the intermediates. The catalyst interacts with the substrate, forming a cyclic species that enhances the formation of succinic acid versus 3-hydroxypropanoic acid.
- Carnevali, Davide,Rigamonti, Marco G.,Tabanelli, Tommaso,Patience, Gregory S.,Cavani, Fabrizio
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- Treatment of o-tert-Butyl phenol micro-polluted water with electro-oxidation and microporous aeration: Method development, performance evaluation and mechanism study
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This study investigated the treatment of organic micro-pollutants in drinking water using a combination of electro-oxidation and microporous aeration (EOMA) technique. Results indicated that microporous aeration enhanced the turbulence of reaction solution and improved the efficiency of organic contaminant removal two-fold versus electro-oxidation alone. o-tert-Butyl phenol (OTBP) was used as a representative pollutant. 1600 mL OTBP solution contained 160 mg sodium sulfate and 2 mL 30 % hydrogen peroxide. When the current density was 5 mA cm-2, 1 and 2 mg L-1 o-tert-butyl phenol was removed up to 98.0 and 75.1 %, respectively. The major intermediate products included trimethylacetic acid, succinic acid and other acid. These have much less toxicity than o-tert-butyl phenol. After 30 min, the organics were mineralized completely. Electro-oxidation and microporous aeration was applied to actual source water that was contaminated by complicated organics. No toxicity was shown to algae growth after 15 min of treatment and total organic carbon was removed completely after 30 min.
- Chen
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- Tailored design of palladium species grafted on an amino functionalized organozinc coordination polymer as a highly pertinent heterogeneous catalyst
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The design of a highly active and stable heterogeneous palladium catalyst is gaining a lot of attention because of its increasing importance in the organic syntheses of commodity chemicals. Herein, we report the tailored synthesis of palladium species grafted on a highly stable amino functionalized organozinc coordination polymer (denoted as Pd/AZC) and its extraordinary catalytic performances in the Suzuki-Miyaura coupling (SMC) reaction. It achieved the highest turnover number of 2106 720 (>99% yield) in air among the most reported palladium catalysts for the SMC reaction of bromobenzene. The as-prepared Pd/AZC composite is also successfully applied for the catalysis of Mizoroki-Heck coupling, hydrogenation of nitro, and -CC- functional groups. Since the developed AZC support has thermal stability at least up to 573 K, it possesses high potential for grafting various metal species as catalytically active centers for a wide range of metal-catalyzed reactions. This journal is
- Choudhary,Nishimura,Ebitani
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- HPLC studies on the organic subset of the oscillatory BZ reaction. 2. Two different types of malonyl radicals in the Ce4+-malonic acid reaction
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Applying combined HPLC and NMR techniques, it was found that, besides the already known 1,1,2,2-ethanetetracarboxylic acid (ETA), monomalonyl malonate (MAMA) is also a product of the Ce4+-malonic acid reaction. This is indirect evidence that two different types of organic radicals are formed in the reaction: the alkyl and the carboxylato malonyl radicals. While ETA is a recombination product of two alkyl radicals, MAMA is formed in the recombination of one alkyl and one carboxylato radical.
- Sirimungkala, Atchara,Foersterling, Horst-Dieter,Noszticzius, Zoltan
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- Anodic Oxidation of Cyclohexanone on Lead Dioxide Electrode in Aqueous Sulfuric Acid Solution
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The electrolytic behavior of cyclohexanone was examined by potentiometry with rotating disk electrode as well as by product analyses.The reaction was activation controlled and the reaction orders were first with respect to cyclohexanone and zero for proton.Cyclohexanone reacted by approximately 6 electrons to give adipic acid mainly which accumulated proportionally to the electricity consumed.Changes in temperature, proton concentration, and current denisty resulted in only minor effects on the reaction.In neutral solution, however, the oxidation was suppressed and oxygen evolution dominated.Other electrode materials such as Pt, graphite, RuO2, and PtO2 were inactive.The chemical oxidation with PbO2 itself did not occur.From these facts, reaction mechanism was discussed.
- Kunai, Atsutaka,Hatoh, Kazuhito,Hirano, Yoshinobu,Harada, Junji,Sasaki, Kazuo
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- Poly-(styrene sulphonic acid): An acid catalyst from polystyrene waste for reactions of interest in biomass valorization
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This article reports on the use of poly-(styrene sulphonic acid) (PSSA) prepared by sulphonation of polystryrene waste as catalyst in reactions demanding acid sites. Two different waste derived catalysts (waste to catalyst, WTC) were studied: soluble PSSA (WTC-PSSA) and solid SiO2-PSSA nanocomposite (WTC-SiO2-PSSA). The catalytic properties of these waste derived acid catalysts have been explored in three different reactions of interest in biomass valorization: biodiesel synthesis, xylose dehydration to furfural and furfural oxidation to maleic and succinic acids. The results show that both soluble and nanocomposite WTC catalysts present promising catalytic properties. The WTC-PSSA requires ultrafiltration for reutilization whereas the WTC-SiO2-PSSA can be separated from the reaction mixtures by more usual techniques (centrifugation or conventional filtration). Further research is required for improving the hydrothermal stability of WTC-SiO2-PSSA in order to substantially reduce the leaching of polymer that takes place during the catalytic runs.
- Alonso-Fagúndez,Laserna,Alba-Rubio,Mengibar,Heras,Mariscal,Granados, M. López
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- SELECTIVE ANODIC OXIDATION OF TETRAHYDROFURAN
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The anodic oxidation of tetragydrofuran in acid aqueous electrolytes has been investigated in detail.Selective oxidation to 2-hydroxy tetrahydrofuran has been found to proceed.Under optimum conditions (smooth platinum, high current densities, 200 - 400 mA/cm2, 1 - 6 M THF, 1 M H2SO4, 35 deg C, quasi divided cells), the product was obtained in batch type laboratory scale (60percent of 2 F/mol conversion) with 70percent current efficiency and 95percent selectivity.Only traces of butyrolactone and succinic acid, the dominating products in the case of PbO2 anodes, were found.Oxygen is the main side product.
- Wermeckes, Bernd,Beck, Fritz,Schulz, Harry
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- Catalyst for catalytic oxidation of furfural to prepare maleic acid and application thereof
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A catalyst for catalytic oxidation of furfural to prepare maleic acid, relating to the technical field of renewable energy. The catalyst is a mixture of a bromide and a base. A method for preparing the catalyst in catalytic oxidation of furfural to prepare maleic acid. The method includes: mixing the furfural, the bromide-base, an oxidant and a solvent to carry out a reaction to obtain the maleic acid. The present invention has the advantages that the method has a relatively high conversion rate of furfural and a relatively high yield of maleic acid, the conversion rate of furfural is up to 99%, the yield of maleic acid is up to 68.04%; and the catalyst has a high catalytic selectivity and reusability.
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Page/Page column 10-12
(2022/02/10)
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- An efficient method for the catalytic aerobic oxidation of cycloalkanes using 3,4,5,6-Tetrafluoro-N-Hydroxyphthalimide (F4-NHPI)
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N-Hydroxyphthalimide (NHPI) is known to be an effective catalyst for the oxidation of hydrocarbons. The catalytic activity of NHPI derivatives is generally increased by introducing an electron-withdrawing group on the benzene ring. In a previous report, two NHPI derivatives containing fluorinated alkyl chain were prepared and their catalytic activity was investigated in the oxidation of cycloalkanes. It was found that the fluorinated NHPI derivatives showed better yields for the oxidation reaction. As a continuation of our work with fluorinated NHPI derivatives, our next aim was to investigate the catalytic activity of the NHPI derivatives by introducing fluorine atoms in the benzene ring of NHPI. In the present research, 3,4,5,6-Tetrafluoro-N-Hydroxyphthalimide (F4-NHPI) is prepared and its catalytic activity has been investigated in the oxidation of two different cycloalkanes for the first time. It has been found that F4-NHPI showed higher catalytic efficiency compared with that of the parent NHPI catalyst in the present reactions. The presence of a fluorinated solvent and an additive was also found to accelerate the oxidation.
- Guha, Samar K.,Ishii, Yasutaka
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p. 327 - 335
(2021/12/13)
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- Labile Photo-Induced Free Radical in α-Ketoglutaric Acid: a Universal Endogenous Polarizing Agent for In Vivo Hyperpolarized 13C Magnetic Resonance
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Hyperpolarized (HP) 13C magnetic resonance enables non-invasive probing of metabolism in vivo. To date, only 13C-molecules hyperpolarized with persistent trityl radicals have been injected in humans. We show here that the free radical photo-induced in alpha-ketoglutaric acid (α-KG) can be used to hyperpolarize photo-inactive 13C-molecules such as [1-13C]lactate. α-KG is an endogenous molecule with an exceptionally high radical yield under photo-irradiation, up to 50 %, and its breakdown product, succinic acid, is also endogenous. This radical precursor therefore exhibits an excellent safety profile for translation to human studies. The labile nature of the radical means that no filtration is required prior to injection while also offering the opportunity to extend the 13C relaxation time in frozen HP 13C-molecules for storage and transport. The potential for in vivo metabolic studies is demonstrated in the rat liver following the injection of a physiological dose of HP [1-13C]lactate.
- Brindle, Kevin M.,Cheng, Tian,Comment, Arnaud,Gaunt, Adam P.,Hesse, Friederike,Lewis, Jennifer S.,Marco-Rius, Irene
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supporting information
(2021/12/09)
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- Cyanide as a primordial reductant enables a protometabolic reductive glyoxylate pathway
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Investigation of prebiotic metabolic pathways is predominantly based on abiotically replicating the reductive citric acid cycle. While attractive from a parsimony point of view, attempts using metal/mineral-mediated reductions have produced complex mixtures with inefficient and uncontrolled reactions. Here we show that cyanide acts as a mild and efficient reducing agent mediating abiotic transformations of tricarboxylic acid intermediates and derivatives. The hydrolysis of the cyanide adducts followed by their decarboxylation enables the reduction of oxaloacetate to malate and of fumarate to succinate, whereas pyruvate and α-ketoglutarate themselves are not reduced. In the presence of glyoxylate, malonate and malononitrile, alternative pathways emerge that bypass the challenging reductive carboxylation steps to produce metabolic intermediates and compounds found in meteorites. These results suggest a simpler prebiotic forerunner of today’s metabolism, involving a reductive glyoxylate pathway without oxaloacetate and α-ketoglutarate—implying that the extant metabolic reductive carboxylation chemistries are an evolutionary invention mediated by complex metalloproteins. [Figure not available: see fulltext.].
- Krishnamurthy, Ramanarayanan,Pulletikurti, Sunil,Yadav, Mahipal,Yerabolu, Jayasudhan R.
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p. 170 - 178
(2022/02/11)
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- Oxidation of cyclohexanone and/or cyclohexanol catalyzed by Dawson-type polyoxometalates using hydrogen peroxide
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The oxidation of cyclohexanone, cyclohexanol or cyclohexanone/cyclohexanol mixture using as catalyst, Dawson-type polyoxometalates (POMs) of formula, α- and β-K6P2W18O62, α-K6P2Mo6W12O62 and α1-K7P2Mo5VW12O62 and hydrogen peroxide, carried out at 90 °C with a reaction time of 20 h, led to a high number of mono- and di-acids which were identified by GC-MS. Levulinic, 6-hydroxyhexanoic, adipic, glutaric and succinic acids, major products were evaluated by HPLC. Regardless of the substrate nature, all POMs exhibited high catalytic activity with 94–99% of conversion, whereas the formation of the different products is sensitively related to both the composition and symmetry of the POMs and the substrate nature. The main products are adipic acid in the presence of α-K6P2Mo6W12O62 and α1-K7P2Mo5VW12O62, levulinic acid in the presence of α1-K7P2Mo5VW12O62 and β-K6P2W18O62 and 6-hydroxyhexanoic acid in the presence of α- and β-K6P2W18O62. Graphical abstract: High catalytic activity was observed with?α- and?β-K6P2W18O62, α-K6P2Mo6W12O62 and α1-K7P2Mo5VW12O62 Dawson-type for the oxidation of cyclohexanone, cyclohexanol or cyclohexanone/cyclohexanol mixture, in the hydrogen peroxide presence, to several oxygenated products. Adipic, levulinic and 6-hydroxyhexanoic acids are the main products. The peroxo- species formed in situ could be the active sites.[Figure not available: see fulltext.]
- Dermeche, Leila,Idrissou, Yasmina,Mazari, Tassadit,Moudjahed, Mohammed,Rabia, Cherifa
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- Strong Metal Phosphide–Phosphate Support Interaction for Enhanced Non-Noble Metal Catalysis
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Strong metal-support interaction (SMSI) is crucial for supported catalysts in heterogeneous catalysis. Here is the first report on strong metal phosphide-phosphate support interaction (SMPSI). The key to SMPSI is the activation of P species on the support, which leads to simultaneous generation of metal phosphide nanoparticles (NPs) and core–shell nanostructures formed by support migration onto the NPs. The encapsulation state of metal phosphide and charge transfer are identical to those of classical SMSIs and can be optimally regulated. Furthermore, the strong interactions of Co2PL/MnP-3 not only significantly enhance the anti-oxidation and anti-acid capability of non-noble metal but also exhibit excellent catalytic activity and stability toward hydrogenating a wide range of compounds into value-added fine chemicals with 100% selectivity, which is even better than Pd/C and Pt/C. The SMPSI construction can be generally extended to other systems such as Ni2PL/Mn3(PO4)2, Co2PL/LaPO4, and CoPL/CePO4. This study provides a new approach for the rational design of advanced non-noble metal catalysts and introduce a novel paradigm for the strong interaction between NPs and support.
- Chen, Zemin,Li, Jiong,Li, Xinyu,Lv, Zhenxing,Zeng, Xiang,Zhang, Ying
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- Preparation method of succinic acid
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The invention discloses a preparation method of succinic acid. The preparation method comprises the following step: with malic acid as a raw material, carrying out one-step reaction in a hydrogen atmosphere in the presence or absence of a non-polar medium and under the action of a metal-solid acid bifunctional catalyst to obtain succinic acid. In the preparation method, the above raw materials can be derived from biomass resources, so dependence on petroleum resources is reduced. By controlling process conditions, succinic acid can be obtained with high yield. The preparation method is simple in process and mild in conditions.
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Paragraph 0028-0076
(2021/06/22)
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- Preparation method of aliphatic dicarboxylic acid
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The invention discloses a preparation method for aliphatic dicarboxylic acids. The preparation method mainly employs acetyl carboxylic acids and/or acetyl carboxylates as raw materials for preparing the aliphatic dicarboxylic acids in a high yield through a nonoxidation process. The preparation technology is simple, efficient, short in flow, less in by-product and suitable for large-scale industrialized production, and the obtained aliphatic dicarboxylic acids are high in purity, and are applicable to synthesize polyesters, polyamides, polyurethanes and other engineering plastic and are used as chemical engineering raw materials and medicine intermediates.
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Paragraph 0066-0067; 0075-0076
(2021/03/17)
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- Catalytic Aerobic Oxidation of Lignocellulose-Derived Levulinic Acid in Aqueous Solution: A Novel Route to Synthesize Dicarboxylic Acids for Bio-Based Polymers
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The world is facing grand and ever-increasing pressures on energy and environmental issues. Using carbon-neutral biomass to prepare monomers such as dicarboxylic acids for degradable polymers is of great significance and an urgent but challenging task. Herein, we report a catalytic route for the synthesis of 2-hydroxy-2-methylsuccinic acid, an excellent monomer: e.g., it is able to remarkably enhance the comprehensive properties of polybutylene succinate as shown herein. By catalytic aerobic oxidation of levulinic acid, a bulk platform chemical derived from lignocellulose, the target product was obtained with a very high selectivity of up to ca. 95%. The mild reaction conditions below 100 °C in water and the low-cost reusable heterogeneous catalyst further make the process highly attractive for applications. This process was also found to be effective for the conversion of homologues of levulinic acid to dicarboxylic acids. We studied the C-C bond rearrangement and the roles of catalysts in the reaction that are highly likely involved in a superoxide anion radical mechanism. This study may provide inspiration for the synthesis of bio-based dicarboxylic acids via alternative routes.
- Che, Li,Jiang, Min,Jiang, Yu,Pang, Jifeng,Song, Lei,Wang, Rui,Zhang, Tao,Zhao, Yu,Zheng, Mingyuan,Zhou, Guangyuan,Zhou, Mo
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p. 11588 - 11596
(2021/09/22)
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- Electrochemical oxidation of diclofenac on CNT and M/CNT modified electrodes
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The electrochemical oxidation of diclofenac (DCF), a non-steroidal anti-inflammatory drug considered as an emerging pollutant (frequently detected in wastewater), was investigated on CNT, Pt/CNT and Ru/CNT modified electrodes based on Carbon Toray in aqueous media. The electroreactivity of DCF on these modified electrodes was studied using cyclic voltammetry and the kinetic parameters were calculated from the scan rate study. Cyclic voltammograms show several oxidation processes, which confirm the interaction between DCF and the catalyst surface necessary for direct oxidation processes. Constant potential electrolysis of DCF was carried out on carbon nanotubes (CNT) and metal supported CNT (M/CNT) modified electrodes, in 0.1 M NaOH and 0.1 M Na2CO3/NaHCO3buffer media. The highest DCF conversion (88% after 8 h of electrolysis) was found in carbonate buffer medium, for Ru/CNT, while the best carbon mineralization efficiency (corresponding to 48% of the oxidized DCF) was obtained on Pt/CNT modified electrode in 0.1 M NaOH medium. The products of the electrolyses were identified and quantified by HPLC-MS, GC-MS, HPLC-UV-RID and IC. The results show the presence of some low molecular weight carboxylic acids, confirming the cleavage of the aromatic rings during the oxidation process.
- Ferreira, M.,Figueiredo, J. L.,Fonseca, A. M.,Güney, S.,Ku?niarska-Biernacka, I.,Neves, I. C.,Parpot, P.,Pereira, M. F. R.,Soares, O. S. G. P.
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p. 12622 - 12633
(2021/07/25)
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- Reactions of 1-Germatranol Hydrate with Dicarboxylic Acids
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Abstract: The reactions of 1-germatranol hydrate with malonic, succinic, maleic, cork, sebacic acids, and bistrimethylsilyl ester of succinic acid, and also of bis(germatran-1-yl)oxane with succinic acid in acetonitrile, water, methanol, and dimethylsulfoxide were studied. In organic solvents, mono- and dicarboxyl-substituted 1-germatranols are formed, which, like 1-germatranol, are reversibly hydrolyzed with water in an acidic medium. Removing water from reaction mixtures due to evaporation and a topochemical reaction increases the yield of esterified 1-germatranol.
- Baryshok, V. P.,Le, G. N. T.
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p. 2430 - 2440
(2022/01/22)
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- Expanding the repertoire of nitrilases with broad substrate specificity and high substrate tolerance for biocatalytic applications
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Enzymatic conversion of nitriles to carboxylic acids by nitrilases has gained significance in the green synthesis of several pharmaceutical precursors and fine chemicals. Although nitrilases from several sources have been characterized, there exists a scope for identifying broad spectrum nitrilases exhibiting higher substrate tolerance and better thermostability to develop industrially relevant biocatalytic processes. Through genome mining, we have identified nine novel nitrilase sequences from bacteria and evaluated their activity on a broad spectrum of 23 industrially relevant nitrile substrates. Nitrilases from Zobellia galactanivorans, Achromobacter insolitus and Cupriavidus necator were highly active on varying classes of nitriles and applied as whole cell biocatalysts in lab scale processes. Z. galactanivorans nitrilase could convert 4-cyanopyridine to achieve yields of 1.79 M isonicotinic acid within 3 h via fed-batch substrate addition. The nitrilase from A. insolitus could hydrolyze 630 mM iminodiacetonitrile at a fast rate, effecting 86 % conversion to iminodiacetic acid within 1 h. The arylaliphatic nitrilase from C. necator catalysed enantioselective hydrolysis of 740 mM mandelonitrile to (R)-mandelic acid in 4 h. Significantly high product yields suggest that these enzymes would be promising additions to the suite of nitrilases for upscale biocatalytic application.
- Rayavarapu, Pratima,Shah, Shikha,Sunder, Avinash Vellore,Wangikar, Pramod P.
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p. 289 - 296
(2020/05/18)
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- 1,3,2-Diazaphospholenes Catalyze the Conjugate Reduction of Substituted Acrylic Acids
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The potent nucleophilicity and remarkably low basicity of 1,3,2-diazaphospholenes (DAPs) is exploited in a catalytic, metal-free 1,4-reduction of free α,β-unsaturated carboxylic acids. Notably, the reduction occurs without a prior deprotonation of the carboxylic acid moiety and hence does not consume an additional hydride equivalent. This highlights the excellent nucleophilic character and low basicity of DAP-hydrides. Functional groups such as Cbz group or alkyl halides which can be problematic with classical transition-metal catalysts are well tolerated in the DAP-catalyzed process. Moreover, the transformation is characterized by a low catalyst loading, mild reaction conditions at ambient temperature as well as fast reaction times and high yields. The proof-of-principle for a catalytic enantioselective version is described.
- Reed, John H.,Cramer, Nicolai
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p. 4262 - 4266
(2020/07/13)
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- Catalytic transfer hydrogenation of maleic acid with stoichiometric amounts of formic acid in aqueous phase: Paving the way for more sustainable succinic acid production
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The aqueous phase hydrogenation of maleic acid (MAc) to succinic acid (SAc) is demonstrated in the absence of any organic solvent and using stoichiometric amount of formic acid (FAc) as source of H2. Among the different noble metals (Pd, Au, Ru, Pt and Rh) and supports investigated (γ-Al2O3, TiO2, CeO2, ZrO2, WO3, CeZrO4, carbon, nicanite, SiO2 and TS-1), Pd/C was identified as the best catalyst. We observe that the undesirable formation of malic acid (MalAc) by hydration of MAc must be prevented. The transformation of MAc to SAc with negligible formation of MalAc is possible by using relatively mild temperature (140-150 °C) and a high catalyst to MAc ratio (i.e. fixed bed continuous flow reactor). Using the carboxylate forms (disodium maleate and sodium formate) instead of the acids results in an increase of the reaction rate. In a fixed bed reactor under a continuous flow of 15 wt% of MAc at a WHSV = 12 h-1 (contact time = 5 min), at 150 °C, 10 bar of N2 and using a formic acid/maleic acid molar ratio = 1, a yield of SAc close to 98% was obtained, equivalent to a productivity of 1.87 g SAc per gcat per·h. Leaching of Pd was below 0.02 ppm. No deactivation was observed in long term experiments at 150 °C (ca. 730 h), although the characterization of the used catalyst by CO chemisorption and TEM and XPS studies showed certain sintering of Pd particles. Regarding the mechanism of the reaction, kinetic isotopic experiments using deuterated DCOOH indicated that the reaction must essentially proceed via catalytic transfer hydrogenation, formyl H of formic acid is involved in the rate determining step of the reaction. When using maleate and formate sodium salts, the second H needed for the reaction is supplied by the solvent (H2O molecules). A preliminary environmental assessment (Life Cycle Analysis, LCA) of this CTH approach indicates that for relevant environmental categories of the LCA (such as climate change and consumption of fossil resources) the CTH process is greener than conventional hydrogenation process; the benefits are even larger if biomass-derived FAc is involved.
- López Granados,Moreno,Alba-Rubio,Iglesias,Martín Alonso,Mariscal
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supporting information
p. 1859 - 1872
(2020/04/07)
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- Metal-Free Photocatalytic Hydrogenation Using Covalent Triazine Polymers
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Photocatalytic hydrogenation of biomass-derived organic molecules transforms solar energy into high-energy-density chemical bonds. Reported herein is the preparation of a thiophene-containing covalent triazine polymer as a photocatalyst, with unique donor-acceptor units, for the metal-free photocatalytic hydrogenation of unsaturated organic molecules. Under visible-light illumination, the polymeric photocatalyst enables the transformation of maleic acid into succinic acid with a production rate of about 2 mmol g?1 h?1, and furfural into furfuryl alcohol with a production rate of about 0.5 mmol g?1 h?1. Great catalyst stability and recyclability are also measured. Given the structural diversity of polymeric photocatalysts and their readily tunable optical and electronic properties, metal-free photocatalytic hydrogenation represents a highly promising approach for solar energy conversion.
- He, Qing,Hu, Yongpan,Huang, Wei,Li, Yanguang,Li, Youyong,Wang, Hongshuai,Yang, Ping,Zhou, Yuan
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supporting information
p. 14378 - 14382
(2020/07/04)
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- Oxidation of biomass-derived furans to maleic acid over nitrogen-doped carbon catalysts under acid-free conditions
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Maleic acid (MA) is a platform chemical used for synthesizing high-value polymers. Although MA can be produced from biomass-derived furfural, so far, only acidic catalysts have been proposed. Herein, for the first time, we report an acid-free furfural-to-MA conversion using nitrogen-doped carbon (NC) as an effective catalyst with the assistance of hydrogen peroxide (H2O2) as an oxidant. A high MA yield (61%) can be achieved over the NC-900 catalyst at 80 °C. The effects of reaction conditions, including H2O2 concentration, solvent type, reaction temperature, and time were systematically studied in detail and optimized. The ZIF-8-derived NC catalyst exhibited high activity owing to the existence of high graphitic nitrogen (N-Q) content in the carbon framework. The kinetics study indicates that the oxidation of furfural to MA over the NC-900 catalyst is via the formation of 5-hydroxy-furan-2(5H)-one as the main intermediate. Further, NC-900 can convert a variety of biomass-derived furan compounds to MA under acid-free conditions, indicating the versatility and applicability of the present acid-free, NC-based catalytic system.
- Ahamad, Tansir,Alshehri, Saad M.,Boo, Jing Rou,Liu, Chia-Hung,Matsagar, Babasaheb M.,Van Nguyen, Chi,Wu, Kevin C.-W.
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p. 1498 - 1506
(2020/03/23)
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- Efficient production of adipic acid from 2-methoxycyclohexanone by aerobic oxidation with a phosphotungstic acid catalyst
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Oxidative cleavage reaction of 2-methoxycyclohexanone (2-MCO) to adipic acid (AA) and methanol with O2 in water solvent was investigated. 2-MCO and AA are one of the lignin-based compounds produced via hydrogenation of guaiacol and an important monomer in industry, respectively. Various vanadium compounds and heteropolyacids were tested as homogeneous catalysts because vanadium compounds, especially phosphomolybdovanadic acids, have been known to be active in various oxidative cleavage reactions with O2. Simple vanadium-free phosphotungstic acid (H3PW12O40), which has not been regarded as an oxidation catalyst using O2 as the oxidant, showed good catalytic activity and excellent selectivity to AA. The carbon-based AA yield reached 74% (86% in molar basis) and this value was higher than those obtained with vanadium-based catalysts. A reuse test and 31P NMR confirmed that the H3PW12O40 catalyst was stable and reusable. Kinetic studies and the reaction test using a radical inhibitor suggested that the reaction mechanism is not auto-oxidation involving free radicals. Instead, the substrate was first activated by one-electron oxidation by H3PW12O40 catalyst and then reacted with O2.
- Hatakeyama, Kosuke,Nakagawa, Yoshinao,Tamura, Masazumi,Tomishige, Keiichi
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p. 4962 - 4974
(2020/08/25)
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- Electrochemical oxidation of amoxicillin on carbon nanotubes and carbon nanotube supported metal modified electrodes
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The electrolysis of amoxicillin (AMX) was carried out on CNT, Pt/CNT and Ru/CNT modified electrodes based on Carbon Toray in 0.1 M NaOH, 0.1 M NaCl and 0.1 M Na2CO3/NaHCO3 buffer (pH 10) media with the aim of studying the significance of two factors, electrode material and pH, on the oxidative degradation and mineralization of AMX. For this purpose, the electrolysis products were identified by HPLC-MS and GC–MS, and quantified by HPLC-UV-RID and IC. The highest carbon mineralization efficiency, corresponding to 30% of the oxidized AMX, was found for Pt/CNT modified electrode in carbonate buffer medium. Regarding to the AMX conversion, the results show that the effect of pH is higher than that of the electrode material. Principal component analysis allowed to determine the experimental parameters vs. product distribution relationship and to elucidate the oxidation pathways for the studied electrodes. The results show that the hydroxylation of the aromatic ring and the nitrogen atom play an important role on the efficient degradation of AMX.
- Ferreira, Marta,Kuzniarska-Biernacka, Iwona,Fonseca, António M.,Neves, Isabel C.,Soares, Olívia S.G.P.,Pereira, Manuel F.R.,Figueiredo, José L.,Parpot, Pier
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p. 322 - 331
(2019/07/10)
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- Lignin-fueled photoelectrochemical platform for light-driven redox biotransformation
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The valorization of lignin has significant potential in producing commodity chemicals and fuels from renewable resources. However, the catalytic degradation of lignin is kinetically challenging and often requires noble metal catalysts to be used under harsh and toxic conditions. Here, we report the bias-free, solar reformation of lignin coupled with redox biotransformation in a tandem structure of a BiVO4 photoanode and perovskite photovoltaic. The tandem structure compensates for the potential gap between lignin oxidation and biocatalytic reduction through artificial Z-schematic absorption. We found that the BiVO4-catalyzed photoelectrochemical oxidation of lignin facilitated the fragmentation of higher molecular weight lignin into smaller carboxylated aliphatic and aromatic acids. Lignin oxidation induced photocurrent generation at the photoanode, which enabled efficient electroenzymatic reactions at the cathode. This study successfully demonstrates the oxidative valorization of lignin as well as biocatalytic reductions (e.g., CO2-to-formate and α-ketoglutarate-to-l-glutamate) in an unbiased biocatalytic PEC platform, which provides a new strategic approach for photo-biocatalysis using naturally abundant renewable resources.
- Boonmongkolras, Passarut,Choi, Eun-Gyu,Han, Seunghyun,Kim, Jinhyun,Kim, Kayoung,Kim, Yong Hwan,Lee, Sahng Ha,Lee, Yang Woo,Park, Chan Beum,Shin, Byungha,Trang, Nguyen Vu Thien,Wang, Ding
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supporting information
p. 5151 - 5160
(2020/08/25)
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- Synthesis of N-unsubstituted cyclic imides from anhydride with urea in deep eutectic solvent (DES) choline chloride/urea
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N-Unsubstituted cyclic imides were readily synthesized in deep eutectic solvent (DES) choline chloride (ChCl)/urea from anhydrides with urea. Urea serves as both a DES component and a nitrogen source, which endows the protocol with advantages of smooth reaction, easy separation of products, simple recovery and recycling of ChCl/urea.
- Liu, Luxiao,Zhang, Hong-Yu,Yin, Guohui,Zhang, Yuecheng,Zhao, Jiquan
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p. 1351 - 1357
(2019/11/19)
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- Enhanced photocatalytic degradation of 2-thiobenzimidazole by the tris(8-quinolinolato)cobalt(iii) complex through peroxide adduct formation: Theoretical and experimental investigations
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Photo-initiated oxidative degradation of 2-thiobenzimidazole (2-TBI) was studied using different semiconducting metal complexes derived from 8-hydroxyquinoline with the general formula, [MQ3C2H5OH] [Q = 8-quinolinolato anion; M = Cr3+, (CrQ3); Co3+, (CoQ3); Fe3+, (FeQ3)]. The degradation kinetics was monitored via UV-vis spectroscopy perceiving the changes in absorbance to subtract. The effect of pH and visible light irradiation on degradation was studied observing a significant increment in the oxidation rate with the presence of visible light whenever CoQ3 is used as a catalyst. By using density functional theory (DFT), it was found that the transition state energy of the adduct formed between CoQ3 and H2O2 is very low compared with other studied catalysts, which activates the formation of OH radicals from H2O2 increasing the 2-TBI degradation rate. In addition, a thermodynamically feasible degradation mechanism was proposed by calculating energy barriers involved in the 2-TBI oxidation pathway.
- Aguilar, Carlos Alberto Huerta,Narayanan, Jayanthi,López, José Abraham Balderas,Flores-Alamo, Marcos,Contreras, Enrique Fernando Velázquez,Gastélum, Karla Alejandra López,Alonzo, Fernando Rocha,Cabrera, Cristian Brayan Palacios,Cuevas, Alan Javier Santiago
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p. 4786 - 4797
(2020/04/03)
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- Synthesis of unstrained Criegee intermediates: inverse a-effect and other protective stereoelectronic forces can stop Baeyer-Villiger rearrangement of ?-hydroperoxy-?-peroxylactones
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How far can we push the limits in removing stereoelectronic protection from an unstable intermediate?We address this question by exploring the interplay between the primary and secondary stereoelectronic effects in the Baeyer-Villiger (BV) rearrangement by experimental and computational studies of ?-OR-substituted ?-peroxylactones, the previously elusive non-strained Criegee intermediates (CI). These new cyclic peroxides were synthesized by the peroxidation of ?-ketoesters followed byin situcyclization using a BF3·Et2O/H2O2system. Although the primary effect (alignment of the migrating C-Rmbond with the breaking O-O bond) is active in the 6-membered ring, weakening of the secondary effect (donation from the OR lone pair to the breaking C-Rmbond) provides sufficient kinetic stabilization to allow the formation and isolation of stable ?-hydroperoxy-?-peroxylactones with a methyl-substituent in the C6-position. Furthermore, supplementary protection is also provided by reactant stabilization originating from two new stereoelectronic factors, both identified and quantified for the first time in the present work. First, an unexpected boat preference in the ?-hydroperoxy-?-peroxylactones weakens the primary stereoelectronic effects and introduces a ~2 kcal mol-1Curtin-Hammett penalty for reacquiring the more reactive chair conformation. Second, activation of the secondary stereoelectronic effect in the TS comes with a ~2-3 kcal mol-1penalty for giving up the exo-anomeric stabilization in the 6-membered Criegee intermediate. Together, the three new stereoelectronic factors (inverse a-effect, misalignment of reacting bonds in the boat conformation, and the exo-anomeric effect) illustrate the richness of stereoelectronic patterns in peroxide chemistry and provide experimentally significant kinetic stabilization to this new class of bisperoxides. Furthermore, mild reduction of ?-hydroperoxy-?-peroxylactone with Ph3P produced an isolable ?-hydroxy-?-peroxylactone, the first example of a structurally unencumbered CI where neither the primary nor the secondary stereoelectronic effect are impeded. Although this compound is relatively unstable,it does not undergo the BV reactionand instead follows a new mode of reactivity for the CI - a ring-opening process.
- Vil', Vera A.,Barsegyan, Yana A.,Kuhn, Leah,Ekimova, Maria V.,Semenov, Egor A.,Korlyukov, Alexander A.,Terent'ev, Alexander O.,Alabugin, Igor V.
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p. 5313 - 5322
(2020/06/03)
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- Directly Microwave-Accelerated Cleavage of C?C and C?O Bonds of Lignin by Copper Oxide and H2O2
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Model erythro, phenolic, and nonphenolic lignin β-O-4 dimer compounds are treated with copper oxide and H2O2 at the electronic field maximum position of a single-mode 2.45 GHz microwave system equipped with a cavity resonator. The products obtained through microwave heating and oil-bath heating with the same reaction vessel and temperature profile are quantitatively compared. Dimer degradation is found to proceed through consecutive elementary reactions. The phenolic dimer is dehydroxylated and this is followed by the spontaneous cleavage of Cα?Cβ and C?O?C bonds to produce guaiacol, vanillin, and vanillic acid. The reaction of the nonphenolic dimer produces veratric acid, veratraldehyde, and guaiacol. Microwave irradiation accelerates cleavage of the side chain and the oxidation of vanillin to vanillic acid. However, no acceleration of veratraldehyde oxidation to veratric acid or aromatic ring cleavage to produce dicarboxylic acids is observed. The selective acceleration of elementary reactions during the degradation of model lignin compounds indicates that microwaves interact with reaction intermediates that are sensitive to electromagnetic waves.
- Qu, Chen,Ito, Keigo,Katsuyama, Isamu,Mitani, Tomohiko,Kashimura, Keiichiro,Watanabe, Takashi
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p. 4510 - 4518
(2020/05/18)
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- Conversion of Wood Based Hemicellulose Prehydrolysate into Succinic Acid Using a Heterogeneous Acid Catalayst in a Biphasic System
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A novel approach for the conversion of biomass based hemicellulose prehydrolysate to high value succinic acid has been investigated using a heterogeneous acid catalyst, Amberlyst 15 and hydrogen peroxide. A vital intermediate in this process, furfural, was oxidized in a biphasic system to produce succinic acid. Production of furfural in good yields is a limiting step in such processes for a number of reasons. Among the organic solvents evaluated, toluene was found to be an ideal solvent for furfural extraction and facilitated the conversion of furfural to succinic acid. Simultaneous extraction of furfural into the organic solvent as it is produced, increased the overall yield. It was observed that the developed method resulted in a succinic acid yield of 49% from the furfural obtained from hemicellulose prehydrolysate. It was found that 50 mg of Amberlyst 15 per mmole of furfural resulted in 100% FA conversion in less time.
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Paragraph 0065; 0075
(2020/01/08)
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- Aerobic oxidation of C4-C6 α,ω-diols to the diacids in base-free medium over zirconia-supported (bi)metallic catalysts
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Oxidation of aliphatic α,ω-diols is a potentially interesting route to the production of valuable α,ω-diacids or ω-hydroxy acids for various polymer synthesis. 1,4-Butanediol (BDO), 1,5-pentanediol (PDO) and 1,6-hexanediol (HDO) are particularly attractive since they may be obtained from lignocellulosic biomass. The aqueous aerobic oxidation of these diols to the corresponding diacids was investigated in water over a set of Au, Pt, Au-Pt and Au-Pd catalysts supported on zirconia at 70 °C or 90 °C under 40 bar air. The nature of the metallic catalyst influenced the distribution of products as oxidation proceeded. The longer the carbon chain linking the terminal alcohol groups, the higher the yield of the diacid. The best yields of succinic acid, glutaric acid and adipic acid reached 83, 84 and 96% from BDO, PDO and HDO, respectively, over Au-Pt/ZrO2. There was some evidence of decarbonylation of the α,ω-hydroxyaldehyde at the early stage of the reaction. The presence of the hydroxyl substituent in 1,2,6-hexanetriol significantly slowed the oxidation rates compared with HDO. Besides, oxidation of PDO or HDO was highly selective to the ω-hydroxycarboxylate in moderate alkaline medium (NaOH/diol = 2) over Au/ZrO2 (90-93%).
- Mounguengui-Diallo, Modibo,Sadier, Achraf,Da Silva Perez, Denilson,Nikitine, Clémence,Puchot, Laura,Habibi, Youssef,Pinel, Catherine,Perret, Noémie,Besson, Michèle
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p. 9873 - 9885
(2019/07/04)
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- Reactivity control of a photocatalytic system by changing the light intensity
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We report a novel light-intensity dependent reactivity approach allowing us to selectively switch between triplet energy transfer and electron transfer reactions, or to regulate the redox potential available for challenging reductions. Simply by adjusting the light power density with an inexpensive lens while keeping all other parameters constant, we achieved control over one- and two-photon mechanisms, and successfully exploited our approach for lab-scale photoreactions using three substrate classes with excellent selectivities and good product yields. Specifically, our proof-of-concept study demonstrates that the irradiation intensity can be used to control (i) the available photoredox reactivity for reductive dehalogenations to selectively target either bromo- or chloro-substituted arenes, (ii) the photochemical cis-trans isomerization of olefins versus their photoreduction, and (iii) the competition between hydrogen atom abstraction and radical dimerization processes.
- Kerzig, Christoph,Wenger, Oliver S.
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p. 11023 - 11029
(2019/12/28)
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- Preparation method of medical intermediate succinic acid
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The invention discloses a preparation method of a medical intermediate succinic acid. The preparation method specifically comprises the following steps: first, preparing a compound catalyst accordingto a combination of a coprecipitation method and a sol-gel method, and then preparing a sodium chloride solution, the mass concentration of which is 20-30%; adding acetylpropionic acid and N, N-dimethylformamide into a three-mouth flask with a condensing tube, then adding the sodium chloride solution and a catalyst to be stirred and mixed and slowly heating the mixture to 80-120 DEG C to stir forreaction, and after the reaction, carrying out filtration and collecting a filtrate; adding a hydrochloric acid solution into the filtrate to adjust the pH of the filtrate to 2-3, carrying out filtration, and drying the solid obtained by filtration to prepare succinic acid. The method is simple to operate and high in product yield.
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Paragraph 0028; 0035; 0042; 0049; 0051; 0056-0057; 0063
(2019/02/26)
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- Reaction of Lithium Acylate α-Carbanions with Carbon Tetrabromide
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Lithium acylate α-carbanions generated by metalation of acetic, butanoic, and 2-methylpropanoic acids with lithium diisopropylamide in THF under argon reacted with carbon tetrabromide at 20-25°C (2 h) to produce butanedioic acid or its 2,3-diethyl and 2,2,3,3-tetramethyl derivatives, as well as the corresponding 2-bromocarboxylic acids and bromoform. The effect of the halogen nature in carbon tetrahalide (CCl4, CBr4) on the reaction selectivity is discussed.
- Zorin,Zaynashev,Zorin
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p. 1527 - 1531
(2019/12/28)
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- Reactions of Lithium Acylates α-Carbanions with 1,2-Diiodoethane
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The interaction of lithium acylates α-carbanions (obtained via metallation of acetic, butyric, and isobutyric acids with lithium diisopropylamide) with 1,2-diiodoethane under argon in tetrahydrofuran at 20–25°C has proceeded as oxidative cross-coupling of enolate anions to form succinic, 2,3-diethylsuccinic, and 2,2,3,3-tetramethylsuccinic acids with yields 50, 53, and 16%, respectively. The products of sequential nucleophilic substitution of iodine atoms with alkyloxycarbonyl species have not been detected.
- Zorin,Chanysheva,Lenkova,Zorin
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p. 148 - 150
(2019/04/08)
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- METHOD FOR PRODUCING ORGANIC OXIDE HAVING ALICYCLIC HYDROCARBON AS SUBSTRATE, AND CATALYST
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PROBLEM TO BE SOLVED: To provide a method for producing an organic oxide that makes it possible to obtain a product with a high proportion and yield of dicarboxylic acid, by one-stage reaction using a heterogeneous catalyst, in an oxygen oxidation reaction having an alicyclic hydrocarbon as a substrate, and a catalyst. SOLUTION: Having an alicyclic hydrocarbon as a substrate, an oxidation reaction is conducted in an oxygen atmosphere, in the presence of a catalyst having a cluster of 4-60 elements including platinum carried on a carrier, so that an oxidation product containing dicarboxylic acid is obtained. SELECTED DRAWING: Figure 1 COPYRIGHT: (C)2019,JPOandINPIT
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Paragraph 0022; 0092-0114
(2019/11/03)
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- Integrated photocatalytic-biological treatment of triazine-containing pollutants
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The degradation of triazine-containing pollutants including simazine, Irgarol 1051 and Reactive Brilliant Red K-2G (K-2G) by photocatalytic treatment was investigated. The effects of titanium dioxide (TiO2) concentration, initial pH of reaction mixture, irradiation time and ultraviolet (UV) intensity on photocatalytic treatment efficiency were examined. Complete decolorization of K-2G was observed at 60 min photodegradation while only 15 min were required to completely degrade simazine and Irgarol 1051 under respective optimized conditions. High-performance liquid chromatography (HPLC), gas chromatography/mass spectrometry (GC/MS) and ion chromatography (IC) were employed to identify the photocatalytic degradation intermediates and products. Dealkylated intermediates of simazine, deisopropylatrazine and deethyldeisopropylatrazine, and Irgarol 1051 were detected by GC/MS in the initial phase of degradation. Complete mineralization could not be achieved for all triazine-containing pollutants even after prolonged (>72 h) UV irradiation due to the presence of a photocatalysis-resistant end product, cyanuric acid (CA). The toxicities of different compounds before and after photocatalytic treatment were also monitored by three bioassays. To further treat the photocatalysis-resistant end product, a CA-degrading bacterium was isolated from polluted marine sediment and further identified as Klebsiella pneumoniae by comparing the substrate utilization pattern (Biolog microplate), fatty acid composition and 16S rRNA gene sequencing. K. pneumoniae efficiently utilized CA from 1 to 2000 mg/L as a good nitrogen source and complete mineralization of CA was observed within 24 h of incubation. This study demonstrates that the biodegradability of triazine-containing pollutants was significantly improved by the photocatalytic pre-treatment, and this proposed photocatalytic-biological integrated system can effectively treat various classes of triazine-containing pollutants.
- Chan, Cho Yin,Chan, Ho Shing,Wong, Po Keung
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p. 371 - 380
(2019/02/07)
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- Reaction of Lithium Acylate α-Carbanions with Carbon Tetrachloride
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Metalation of acetic, butanoic, or 2-methylpropanoic acid with lithium diisopropylamide in tetrahydrofuran under argon gave the corresponding lithium acylate α-carbanions which reacted with carbon tetrachloride at 20–25°C for 2 h to afford butanedioic acid or its 2,3-diethyl and 2,2,3,3-tetramethyl derivatives, as well as the corresponding α-chlorocarboxylic acids and chloroform. A radical mechanism was proposed for the formation of dicarboxylic and α-chlorocarboxylic acids.
- Zorin,Zaynashev,Zorin
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- Platinum-on-Carbon-Catalyzed Aqueous Oxidative Lactonization of Diols by Using Molecular Oxygen
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A lactonization of various diols catalyzed by platinum on carbon (Pt/C) in water under an atmosphere of molecular oxygen was developed. Derivatives of 1,4- 1,5- and 1,6-diols were transformed into the corresponding five-, six-, and seven-membered lactones by the present oxidative lactonization method.
- Ban, Kazuho,Sajiki, Hironao,Sawama, Yoshinari,Takakura, Ryoya
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supporting information
p. 1919 - 1923
(2019/09/30)
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- PtII-Catalyzed Hydroxylation of Terminal Aliphatic C(sp3)?H Bonds with Molecular Oxygen
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The practical application of Shilov-type Pt catalysis to the selective hydroxylation of terminal aliphatic C?H bonds remains a formidable challenge, due to difficulties in replacing PtIV with a more economically viable oxidant, particularly O2. We report the potential of employing FeCl2 as a suitable redox mediator to overcome the kinetic hurdles related to the direct use of O2 in the Pt reoxidation. For the selective conversion of butyric acid to γ-hydroxybutyric acid (GHB), a significantly enhanced catalyst activity and stability (turnover numbers (TON)>30) were achieved under 20 bar O2 in comparison to current state-of-the-art systems (TON0 was prevented by the addition of monodentate pyridine derivatives, such as 2-fluoropyridine, but also by introducing varying partial pressures of N2 in the gaseous atmosphere. Finally, stability tests revealed the involvement of PtII and FeCl2 in catalyzing the non-selective overoxidation of GHB. Accordingly, in situ esterification with boric acid proved to be a suitable strategy to maintain enhanced selectivities at much higher conversions (TON>60). Altogether, a useful catalytic system for the selective hydroxylation of primary aliphatic C?H bonds with O2 is presented.
- Janssen, Michiel,De Vos, Dirk E.
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supporting information
p. 10724 - 10734
(2019/07/15)
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- Janus Gold Nanostars–Mesoporous Silica Nanoparticles for NIR-Light-Triggered Drug Delivery
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Janus gold nanostar–mesoporous silica nanoparticle (AuNSt–MSNP) nanodevices able to release an entrapped payload upon irradiation with near infrared (NIR) light were prepared and characterized. The AuNSt surface was functionalized with a thiolated photolabile molecule (5), whereas the mesoporous silica face was loaded with a model drug (doxorubicin) and capped with proton-responsive benzimidazole-β-cyclodextrin supramolecular gatekeepers (N 1). Upon irradiation with NIR-light, the photolabile compound 5 photodissociated, resulting in the formation of succinic acid, which induced the opening of the gatekeeper and cargo delivery. In the overall mechanism, the gold surface acts as a photochemical transducer capable of transforming the NIR-light input into a chemical messenger (succinic acid) that opens the supramolecular nanovalve. The prepared hybrid nanoparticles were non-cytotoxic to HeLa cells, until they were irradiated with a NIR laser, which led to intracellular doxorubicin release and hyperthermia. This induced a remarkable reduction in HeLa cells viability.
- Hernández Montoto, Andy,Llopis-Lorente, Antoni,Gorbe, Mónica,M. Terrés, José,Cao-Milán, Roberto,Díaz de Gre?u, Borja,Alfonso, María,Iba?ez, Javier,Marcos, María D.,Orzáez, Mar,Villalonga, Reynaldo,Martínez-Má?ez, Ramón,Sancenón, Félix
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supporting information
p. 8471 - 8478
(2019/07/16)
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- Method for synthesizing succinic acid by catalytic hydrogenation of acetylene double carbonylation product
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The invention provides a method for synthesizing succinic acid by catalytic hydrogenation of an acetylene double carbonylation product and relates to the field of preparation of the succinic acid by an acetylene method. The method is characterized in that the succinic acid is prepared by matching with an acetylene double carbonylation reaction and using an acetylene two-step method. The method comprises the following steps: taking the acetylene double carbonylation product obtained by the acetylene double carbonylation reaction as a raw material; taking an activated carbon loaded active component palladium as in-situ reduction Pd/C catalyst; taking water as a solvent; introducing hydrogen and reacting at the reaction temperature of 40 to 80 DEG C and the pressure of a reaction system of 0.5 to 1.5Mpa for 0.5 to 2 hours; after the acetylene double carbonylation product is completely transformed, naturally cooling filtrate obtained by filtering in a hot state to obtain a succinic acid crystal. The catalyst is prepared by the following steps: firstly, pretreating activated carbon as a catalyst carrier; secondly, loading halogenated palladium by adopting an impregnation method; directly reducing the catalyst in the hydrogenation reaction process; moreover, hydrogenating the acetylene double carbonylation product to obtain the succinic acid. The method has low cost of synthesizing the succinic acid; a preparation method of the catalyst is simple; the catalyst has the advantages of high activity, good selectivity, long service life and the like.
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Paragraph 0032; 0038-0041
(2018/04/03)
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- Electrochemical properties and C-H bond oxidation activity of [Ru(tpy)(pyalk)Cl]+ and [Ru(tpy)(pyalk)(OH)]+
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[Ru(tpy)(pyalk)Cl]Cl (pyalk = 2-(2′-pyridyl)-2-propanol) was synthesized and characterized crystallographically and electrochemically. Upon dissolution in water and acetonitrile, [Ru(tpy)(pyalk)Cl]Cl was found to form [Ru(tpy)(pyalk)Cl]+ and [Ru(tpy)(pyalk)(OH)]+, respectively. The Ru(ii/iii) couple of [Ru(tpy)(pyalk)Cl]+ was found to be relatively low compared to that of other Ru complexes in acetonitrile, but the Ru(iii/iv) couple was not significantly different than other Ru complexes bearing anionic ligands. Pourbaix diagrams were generated for [Ru(tpy)(phpy)(OH2)]+ (phpy = 2-phenylpyridine) and [Ru(tpy)(pyalk)(OH)]+ in water, and it was found that [Ru(tpy)(pyalk)(OH)]+ has a lower Ru(ii/iii) potential than [Ru(tpy)(phpy)(OH2)]+ under neutral to alkaline pH. [Ru(tpy)(pyalk)(OH)]+ was found to catalyze C-H bond hydroxylation of secondary alkanes and epoxidation of alkenes using cerium(iv) ammonium nitrate as the primary oxidant.
- Nilles, Christian K.,Herath, Hashini N. K.,Fanous, Hanna,Ugrinov, Angel,Parent, Alexander R.
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supporting information
p. 9701 - 9708
(2018/08/06)
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- Method for preparing carboxylic acid compound by oxidatively breaking carbon-carbon bond of ketone compound
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The invention relates to a method for directly preparing a carboxylic acid compound by oxidatively breaking a carbon-carbon bond of a ketone compound. The method comprises adding a ketone compound anda catalyst into an organic solvent, putting the solution into a pressure container, sealing the container, and feeding oxygen source gas under a certain pressure into the container, wherein the reaction product is a carboxylic acid compound, the oxygen source gas is oxygen or air, the catalyst is a copper salt catalyst, the organic solvent is one of acetonitrile, dimethyl sulfoxide and N, N-dimethylformamide and the corresponding carboxylic acid product highest yield after the reaction is 99%. The method has a wide application range, is free of alkali assistants and organic ligands and is easy to separate.
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Paragraph 0143; 0144
(2018/06/16)
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- Rearrangements and Tautomeric Transformations of Heterocyclic Compounds in Homogeneous Reaction Systems Furfural–Н2О2–Solvent
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General information on the reactions of furfurals with hydrogen peroxide is given. We have discussed the Baeyer–Villiger rearrangement of furan 2-hydroxyhydroperoxides and tautomeric transformations with proton transfer of 2-hydroxyfuran and β-formylacrylic acid formed in a homogeneous reaction system furfural–Н2О2–solvent under the catalysis with the formed acids. The factors affecting these rearrangements and tautomeric transformations as well as their specificity in comparison with benzene type compounds, and the pathway of the reactions of furan aldehydes with Н2О2 in water have been analyzed. Ketoenol tautomerism of cyclic hemiacetal form of β-formylacrylic acid leading to its transformation into succinic anhydride has been described for the first time.
- Badovskaya,Poskonin
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p. 1568 - 1579
(2018/11/10)
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- The oxidative cleavage of trans-1,2-cyclohexanediol with O2: Catalysis by supported Au nanoparticles
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This paper reports on the catalytic oxidative cleavage of trans-1,2-cyclohexanediol with air, catalysed by supported Au NPs, as one of the steps of a new adipic acid synthesis process. Catalysts proved to be active, with a moderate cyclohexanediol conversion and selectivity to adipic acid close to 70%. The reaction network included several steps in sequence, amongst which the key one is the oxidation of the diol into 2-hydroxycylohexanone, which is then oxidised by air – even in the absence of a catalyst – to adipic acid and lesser amounts of lighter acids, i.e. glutaric and succinic acids. The oxidation of the second hydroxyl moiety in the diol would lead to the formation of 1,2-cyclohexanedione. The latter, however, is rapidly transformed into several by-products, especially glutaric acid, under the basic conditions which are necessary for allowing the reaction to occur at an acceptable rate. With Au-based catalysts, this undesired reaction occurs much more slowly than with the previously investigated Ru hydroxide catalysts. The nature of the support, either TiO2 or MgO, also affected catalytic performance; the best performance was shown by the Au/MgO catalyst which, however, suffered from a remarkable deactivation, found to be due to both the increase in NPs size and the formation of carbonaceous residua on the catalyst surface.
- Solmi, Stefania,Rozhko, Elena,Malmusi, Andrea,Tabanelli, Tommaso,Albonetti, Stefania,Basile, Francesco,Agnoli, Stefano,Cavani, Fabrizio
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- Cyclohexane Oxidation to Adipic Acid Under Green Conditions: A Scalable and Sustainable Process
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This work reports a 1 mol scale catalytic process to synthesize adipic acid directly from cyclohexane in solvent-free conditions using air as oxidant. Catalysts based on vanadium phosphorus oxides were prepared, characterized and tested. They showed good activity and remarkably high selectivity to adipic acid in comparison to other already known heterogeneous catalysts. The use of solvent-free conditions permits the easy separation of the product from the reactant mixture, which is very important from the industrial point of view. The process can be used at industrial scale for sustainable adipic acid synthesis.
- Mazzi, Alberto,Paul, Sébastien,Cavani, Fabrizio,Wojcieszak, Robert
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p. 3680 - 3682
(2018/09/12)
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- Sustainable Synthesis of Oxalic and Succinic Acid through Aerobic Oxidation of C6 Polyols Under Mild Conditions
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The sustainable chemical industry encompasses a shift from the use of fossil carbon to renewable carbon. The synthesis of chemicals from nonedible biomass (cellulosic or oil) represents one of the key steps for “greening” the chemical industry. In this paper, we report the aerobic oxidative cleavage of C6 polyols (5-HMF, glucose, fructose and sucrose) to oxalic acid (OA) and succinic acid (SA) in water under mild conditions using M@CNT and M@NCNT (M=Fe, V; CNT=carbon nanotubes; NCNT=N-doped CNT), which, under suitable conditions, were recoverable and reusable without any loss of efficiency. The influence of the temperature, O2 pressure (P (Formula presented.)), reaction time and stirring rate are discussed and the best reaction conditions are determined for an almost complete conversion of the starting material and a good OA yield of 48 %. SA and formic acid were the only co-products. The former could be further converted into OA by oxidation in the presence of formic acid, resulting in an overall OA yield of >62 %. This process was clean and did not produce organic waste nor gas emissions.
- Ventura, Maria,Williamson, David,Lobefaro, Francesco,Jones, Matthew D.,Mattia, Davide,Nocito, Francesco,Aresta, Michele,Dibenedetto, Angela
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p. 1073 - 1081
(2018/02/28)
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- Double-carbonylation preparation method utilizing palladium to catalyze acetylene
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The invention provides a double-carbonylation preparation method utilizing palladium to catalyze acetylene and relates to the field of preparing succinic acid by an acetylene method. According to thedouble-carbonylation preparation method, acetylene, carbon monoxide and water are utilized as raw materials to be catalyzed and synthesized into succinic acid (anhydride) under the conditions of a reaction temperature as 25 to 75 DEG C and a pressure as 0.1 to 5MPa. To the used catalyst, a palladium compound-lithium halide/hydrogen halide-nitrogenous/phosphine ligand is utilized as the catalyst, wherein n (palladium compound) to n (lithium halide/hydrogen hydride) is equal to 1 to (1 to 10), and n (phosphine/nitrogen ligand) to n (palladium compound) is equal to 1 to (1 to 10). Compared with the prior art, the double-carbonylation preparation method disclosed by the invention has the advantages of moderate reaction conditions, quick reaction speed, high selectivity, simpleness and safety in operation, ability in effectively reducing succinic acid production cost and very good industrial market prospect.
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Paragraph 0026; 0028; 0030; 0032; 0034; 0036
(2018/04/03)
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