- TiO2-mediated photomineralization of 2-chlorobiphenyl: The role of O2
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Photocatalytic mineralization of 2-chlorobiphenyl (2-CB) in aqueous TiO2 suspensions was conducted under four different oxygen partial pressures (Po2) in closed reactors. The observed O2 adsorption equilibrium constant in TiO2 aqueous suspension was 0.88 (kPa)-1 based on the Langmuir-Hinshelwood rate function. Apart from the conventional electron-scavenging function, the dissolved oxygen was critical for the degradation of the hydroxyl intermediates, i.e., 2-chlorobiphenyl-ols and biphenyl-2-ol, which are potentially toxic. Degradation of 2-CB in the irradiated H2O2 aqueous solutions under two different Po2 was also studied for comparison. For UV/H2O2, Po2 does not affect the removal of 2-CB, while reducing the Po2 from 21 to 2 kPa resulted in 35% less CO2 formation after 5 h irradiation. The similar O2-dependent destruction of the hydroxyl intermediates was also observed in the UV/H2O2 system. We propose that molecular O2 acts as a key reactant following the attack of a second ·OH radical during the ring opening in the degradation of the hydroxyl byproducts. Copyright (C) 2000 Elsevier Science Ltd.
- Wang, Yongbing,Hong, Chia-Swee
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- Oxidation of aromatic aldehydes with potassium bromate-bromide reagent and an acidic catalyst
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We report herein an easy oxidation procedure for converting aromatic aldehydes to aromatic carboxylic acids by use of a combination of commercially and readily available potassium bromate with potassium bromide in the presence of hydrochloric acid catalyst.
- Sharma,Robert, Alice R.
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- Bismuth(III)-catalyzed oxidative cleavage of aryl epoxides: substituent effects on the kinetics of the oxidation reaction
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Bismuth(III)mandelate catalyzes the oxidative C-C bond cleavage of a series of styrene epoxides in DMSO, to the corresponding aryl carboxylic acids.The reaction is accelerated in the presence of electron-donating groups substituting the phenyl ring.A good Hammet correlation of log kobs versus ? has been obtained, with a ρ of -1.08.Key words: Bismuth; Aryl epeoxide cleavage; Oxidation; Substituent effects; Bi(III) catalysis; Hammet correlation
- Boisselier, Veronique Le,Dunach, Elisabet,Postel, Michele
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- Chemiluminescence from arylcarbene oxidation: phenylchlorocarbene and (2-chlorophenyl)carbene
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Chemiluminescence is observed in the thermal reaction of phenylchlorocarbene or (2-chloro-phenyl)carbene and O2, matrix-isolated in Ar.The chemiluminescence spectra closely match the phosphorescence of the corresponding carbonyl compounds.The reactivity of both carbenes towards O2 is very different.Singlet carbene phenylchlorocarbene reacts thermally only slowly with O2 up to 60 K.The oxidation products phenylchloroformate, benzoyl chloride and O(3P) are mainly formed photochemically on irradiation of the diazirine precursor.Triplet carbene (2-chlorophenyl)carbene reacts readily with O2 at cryogenic temperatures to give mostly 2-chlorobenzaldehyde-O-oxide.The carbonyl-O-oxide is photochemically easily cleaved to give 2-chlorobenzaldehyde and O(3P).The reaction step leading to carbonyl compounds in their excited states is in both carbene oxidations the recombination of the free carbene and O(3P).
- Sander, Wolfram W.
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- Supported ruthenium hydride catalysts for direct conversion of alcohols to carboxylic acids using styrene oxide as oxidant
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In the present work, the ability of two ruthenium hydride catalysts supported on multiwall carbon nanotubes, [Ru–H@EDT–MWCNT], and gold nanoparticles cored triazine dendrimer, [Ru–H@AuNPs–TD], in the direct conversion of alcohols to carboxylic acids via transfer hydrogenation using styrene oxide as oxidant is reported. Different alcohols were successfully converted to their corresponding carboxylic acids. The results showed that these two heterogeneous catalysts are more efficient than the homogeneous counterpart. In addition, the catalysts were reused several times.
- Ghafouri, Moloud,Moghadam, Majid,Mehrani, Kheirollah,Daneshvar, Anahita
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- SELECTIVE REMOVAL OF ORTHO HALOGENS BY A DIORGANOLANTHANOID
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Reaction of halogenobenzoic acids with bis(pentafluorophenyl)ytterbium(II) in tetrahydrofuran results in selective removal of ortho halogen substituents.
- Deacon, G.B.,MacKinnon, P.I.
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- COBALT CARBONYL-CATALYZED DOUBLE-CARBONYLATION OF O-HALOGENATED BENZOIC ACIDS UNDER PHOTOSTIMULATION
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Cobalt carbonyl-catalyzed double-carbonylation of o-dihalobenzenes and o-halogenated benzoic acids, affording phthalonic acid, was observed in aqueous sodium hydroxide under photostimulation.
- Kashimura, Tsugunori,,Kudo, Kiyoshi,Mori, Sadayuki,Sugita, Nobuyuki
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- Reductions and radical cyclizations of aryl and alkyl bromides mediated by NaBH4 in aqueous base
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Reductions and free radical cyclizations of alkyl- and aryl bromides are effected in aqueous base by NaBH4 in conjunction with a base-soluble dialkyltin(IV) reagent and 4,4'-azobis(4-cyanovaleric acid) (ACVA). The aryl bromides reduce at lower rates under tin-free conditions using simply NaBH4-ACVA.
- Rai, Roopa,Collum, David B.
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- Direct oxidation of alcohols to carboxylic acids over ruthenium hydride catalyst with diphenyl sulfoxide oxidant
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In the present work, a new method for the synthesis of carboxylic acids over ruthenium hydride catalyst is reported. Direct oxidation of alcohols to their corresponding carboxylic acids with diphenyl sulfoxide oxidant over RuHCl(CO)(PPh3)3 catalyst was investigated. Mild reaction conditions, short reaction times and excellent yields make this method as an appealing way for preparation of carboxylic acids.
- Barati, Behjat,Moghadam, Majid,Rahmati, Abbas,Mirkhani, Valiollah,Tangestaninejad, Shahram,Mohammadpoor-Baltork, Iraj
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- Atomically Dispersed Co Clusters Anchored on N-doped Carbon Nanotubes for Efficient Dehydrogenation of Alcohols and Subsequent Conversion to Carboxylic Acids
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The catalytic dehydrogenation of readily available alcohols to high value-added carbonyl compounds is a research hotspot with scientific significance. Most of the current research about this reaction is performed with noble metal-based homogeneous catalysts of high price and poor reusability. Herein, highly dispersed Co-cluster-decorated N-doped carbon nanotubes (Co/N-CNTs) were fabricated via a facile strategy and used for the dehydrogenation of alcohols with high efficiency. Various characterization techniques confirmed the presence of metallic Co clusters with almost atomic dispersion, and the N-doped carbon supports also enhanced the catalytic activity of Co clusters in the dehydrogenation reaction. Aldehydes as dehydrogenation products were further transformed in situ to carboxylic acids through a Cannizzaro-type pathway under alkaline conditions. The reaction pathway of the dehydrogenation of alcohols was clearly confirmed by theoretical calculations. This work should provide an effective and simple approach for the accurate design and synthesis of small Co-clusters catalysts for the efficient dehydrogenation-based transformation of alcohols to carboxylic acids under mild reaction conditions.
- Dong, Zhengping,Fang, Jian,Li, Boyang,Xu, Dan,Zhang, Fengwei,Zhao, Hong,Zhu, Hanghang
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p. 4536 - 4545
(2021/09/22)
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- Cleavage of Carboxylic Esters by Aluminum and Iodine
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A one-pot procedure for deprotecting carboxylic esters under nonhydrolytic conditions is described. Typical alkyl carboxylates are readily deblocked to the carboxylic acids by the action of aluminum powder and iodine in anhydrous acetonitrile. Cleavage of lactones affords the corresponding ω-iodoalkylcarboxylic acids. Aryl acetylates undergo deacetylation with the participation of the neighboring group. This method enables the selective cleavage of alkyl carboxylic esters in the presence of aryl esters.
- Sang, Dayong,Yue, Huaxin,Fu, Yang,Tian, Juan
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p. 4254 - 4261
(2021/03/09)
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- Aerobic oxidation of aldehydes to carboxylic acids catalyzed by recyclable ag/c3 n4 catalyst
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The oxidation of aldehydes is an efficient methodology for the synthesis of carboxylic acids. Herein we hope to report a simple, efficient and recyclable protocol for aerobic oxidation of aldehydes to carboxylic acid by using C3N4 supported silver nanoparticles (Ag/C3N4) as a catalyst in aqueous solution under mild conditions. Under standard conditions, the corresponding carboxylic acids can be obtained in good to excellent yields. In addition, Ag/C3N4 is convenient for recovery and could be reused three times with satisfactory yields.
- Wu, Chaolong,Yao, Xiaoquan,Yu, Min,Zhou, Li,Zhu, Li
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p. 167 - 175
(2021/03/19)
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- MOF-Zn-NHC as an efficient N-heterocyclic carbene catalyst for aerobic oxidation of aldehydes to their corresponding carboxylic acids: Via a cooperative geminal anomeric based oxidation
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As an efficient heterogenous N-heterocyclic carbene (NHC) catalyst, MOF-Zn-NHC was used in the aerobic oxidation of aryl aldehydes to their corresponding carbocyclic acids via an anomeric based oxidation. Features such as mild reaction conditions and no need for a co-catalyst or oxidative reagent can be considered as the major advantages of the presented method in this study. This journal is
- Babaee, Saeed,Zarei, Mahmoud,Zolfigol, Mohammad Ali
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p. 36230 - 36236
(2021/12/02)
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- Bimetallic oxide nanoparticles confined in ZIF-67-derived carbon for highly selective oxidation of saturated C–H bond in alkyl arenes
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Zeolite imidazolate frameworks (ZIFs) have recently emerged as an ideal type of carbon precursors with abundant tailorability. In this work, a series of ZIF-derived porous carbon catalysts have been prepared with encapsulation of bimetallic oxide nanoparticles via simple thermal treatment. The composition and structure of these catalysts were confirmed in detail by different characterization methods. The bimetallic oxide (Mn/Co, Fe/Co, and Cu/Co) nanoparticles were encapsulated in the nitrogen-doped graphitized carbon matrix. Moreover, the hierarchically porous structure and carbon defects were successfully constructed in the carbon catalysts. Additionally, in the selective oxidation of saturated C–H bonds in alkyl arenes, the carbon catalysts demonstrate outstanding performance for the oxidation of C–H bonds to corresponding carboxyl groups. This was due to their unique structure can greatly promote mass transfer and molecular oxygen activation, resulting in high conversion and high selectivity. Remarkably, this work here could also provide a novel strategy to the controllable synthesis of metal–organic frameworks (MOFs)-derived carbon catalysts for enhanced performance in heterogeneous catalysis.
- Huang, Cheng,Su, Xiaoyan,Gu, Xiangyu,Liu, Rui,Zhu, Hongjun
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- Alkali-modified heterogeneous Pd-catalyzed synthesis of acids, amides and esters from aryl halides using formic acid as the CO precursor
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To establish an environmentally friendly green chemical process, we minimized and resolved a significant proportion of waste and hazards associated with conventional organic acids and molecular gases, such as carbon monoxide (CO). Herein, we report a facile and milder reaction procedure, using low temperatures/pressures and shorter reaction time for the carboxyl- and carbonylation of diverse arrays of aryl halides over a newly developed cationic Lewis-acid promoted Pd/Co3O4catalyst. Furthermore, the reaction proceeded in the absence of acid co-catalysts, and anhydrides for CO release. Catalyst reusability was achievedviascalable, safer, and practical reactions that provided moderate to high yields, paving the way for developing a novel environmentally benign method for synthesizing carboxylic acids, amides, and esters.
- Fapojuwo, Dele Peter,Maqunga, Nomathamsanqa Prudence,Meijboom, Reinout,Mogudi, Batsile M.,Molokoane, Pule Petrus,Onisuru, Oluwatayo Racheal,Oseghale, Charles O.
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p. 26937 - 26948
(2021/08/17)
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- Efficiency of lithium cations in hydrolysis reactions of esters in aqueous tetrahydrofuran
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Lithium cations were observed to accelerate the hydrolysis of esters with hydroxides (KOH, NaOH, LiOH) in a water/tetrahydrofuran (THF) two-phase system. Yields in the hydrolysis of substituted benzoates and aliphatic esters using the various hydroxides were compared, and the effects of the addition of lithium salt were examined. Moreover, it was presumed that a certain amount of LiOH was dissolved in THF by the coordination of THF with lithium cation and hydrolyzed esters even in the THF layer, as in the reaction by a phase-transfer catalyst.
- Hayashi, Kazuhiko,Ichimaru, Yoshimi,Sugiura, Kirara,Maeda, Azusa,Harada, Yumi,Kojima, Yuki,Nakayama, Kanae,Imai, Masanori
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p. 581 - 594
(2021/06/06)
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- Oxidative carbon-carbon bond cleavage of 1,2-diols to carboxylic acids/ketones by an inorganic-ligand supported iron catalyst
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The carbon-carbon bond cleavage of 1,2-diols is an important chemical transformation. Although traditional stoichiometric and catalytic oxidation methods have been widely used for this transformation, an efficient and valuable method should be further explored from the views of reusable catalysts, less waste, and convenient procedures. Herein an inorganic-ligand supported iron catalyst (NH4)3[FeMo6O18(OH)6]·7H2O was described as a heterogeneous molecular catalyst in acetic acid for this transformation in which hydrogen peroxide was used as the terminal oxidant. Under the optimized reaction conditions, carbon-carbon bond cleavage of 1,2-diols could be achieved in almost all cases and carboxylic acids or ketones could be afforded with a high conversion rate and high selectivity. Furthermore, the catalytic system was used efficiently to degrade renewable biomass oleic acid. Mechanistic insights based on the observation of the possible intermediates and control experiments are presented.
- Chen, Weiming,Xie, Xin,Zhang, Jian,Qu, Jian,Luo, Can,Lai, Yaozhu,Jiang, Feng,Yu, Han,Wei, Yongge
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supporting information
p. 9140 - 9146
(2021/11/23)
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- Selective oxidation of alkenes to carbonyls under mild conditions
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Herein, a practical and sustainable method for the synthesis of aldehydes, ketones, and carboxylic acids from an inexpensive olefinic feedstock is described. This transformation features very sustainable and mild conditions and utilizes commercially available and inexpensive tetrahydrofuran as the additive, molecular oxygen as the sole oxidant and water as the solvent. A wide range of substituted alkenes were found to be compatible, providing the corresponding carbonyl compounds in moderate-to-good yields. The control experiments demonstrated that a radical mechanism is responsible for the oxidation reaction.
- Huo, Jie,Xiong, Daokai,Xu, Jun,Yue, Xiaoguang,Zhang, Pengfei,Zhang, Yilan
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supporting information
p. 5549 - 5555
(2021/08/16)
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- 1,2-Dibutoxyethane-Promoted Oxidative Cleavage of Olefins into Carboxylic Acids Using O2 under Clean Conditions
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Herein, we report the first example of an effective and green approach for the oxidative cleavage of olefins to carboxylic acids using a 1,2-dibutoxyethane/O2 system under clean conditions. This novel oxidation system also has excellent functional-group tolerance and is applicable for large-scale synthesis. The target products were prepared in good to excellent yields by a one-pot sequential transformation without an external initiator, catalyst, and additive.
- Ou, Jinhua,Tan, Hong,He, Saiyu,Wang, Wei,Hu, Bonian,Yu, Gang,Liu, Kaijian
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p. 14974 - 14982
(2021/10/25)
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- Palladium supported on a novel ordered mesoporous polypyrrole/carbon nanocomposite as a powerful heterogeneous catalyst for the aerobic oxidation of alcohols to carboxylic acids and ketones on water
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Preparation of an ordered mesoporous polypyrrole/carbon (PPy/OMC) composite has been described through a two-step nanocasting process using KIT-6 as a template. Characterization of the PPy/OMC nanocomposite by various analysis methods such as TEM, XRD, TGA, SEM and N2 sorption confirmed the preparation of a material with ordered mesoporous structure, uniform pore size distribution, high surface area and high stability. This nanocomposite was then used for the immobilization of palladium nanoparticles. The nanoparticles were almost uniformly distributed on the support with a narrow particle size of 20-25 nm, confirmed by various analysis methods. Performance of the Pd?PPy/OMC catalyst was evaluated in the aerobic oxidation of various primary and secondary alcohols on water as a green solvent, giving the corresponding carboxylic acids and ketones in high yields and excellent selectivity. The catalyst could also be reused for at least 10 reaction runs without losing its catalytic activity and selectivity. High catalytic efficiency of the catalyst can be attributed to a strong synergism between the PPy/OMC and that of supported Pd nanoparticles.
- Ganji, Nasim,Karimi, Babak,Najafvand-Derikvandi, Sepideh,Vali, Hojatollah
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p. 13616 - 13631
(2020/04/24)
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- A cyclometalated Ir(iii)-NHC complex as a recyclable catalyst for acceptorless dehydrogenation of alcohols to carboxylic acids
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In this work, we have synthesized two new [C, C] cyclometalated Ir(iii)-NHC complexes, [IrCp?(C∧C:NHC)Br](1a,b), [Cp? = pentamethylcyclopentadienyl; NHC = (2-flurobenzyl)-1-(4-methoxyphenyl)-1H-imidazoline-2-ylidene (a); (2-flurobenzyl)-1-(4-formylphenyl)-1H-imidazoline-2-ylidene (b)] via intramolecular C-H bond activation. The molecular structure of complex 1a was determined by X-ray single crystal analysis. The catalytic potentials of the complexes were explored for acceptorless dehydrogenation of alcohols to carboxylic acids with concomitant hydrogen gas evolution. Under similar experimental conditions, complex 1a was found to be slightly more efficient than complex 1b. Using 0.1 mol% of complex 1a, good-to-excellent yields of carboxylic acids/carboxylates have been obtained for a wide range of alcohols, both aliphatic and aromatic, including those involving heterocycles, in a short reaction time with a low loading of catalyst. Remarkably, our method can produce benzoic acid from benzyl alcohol on a gram scale with a catalyst-to-substrate ratio as low as 1?:?5000 and exhibit a TON of 4550. Furthermore, the catalyst could be recycled at least three times without losing its activity. A mechanism has been proposed based on controlled experiments and in situ NMR study.
- Borah, Dhrubajit,Das, Pankaj,Saha, Biswajit,Sarma, Bipul
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p. 16866 - 16876
(2020/12/18)
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- Sequential Connection of Mutually Exclusive Catalytic Reactions by a Method Controlling the Presence of an MOF Catalyst: One-Pot Oxidation of Alcohols to Carboxylic Acids
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A functionalized metal-organic framework (MOF) catalyst applied to the sequential one-pot oxidation of alcohols to carboxylic acids controls the presence of a heterogeneous catalyst. The conversion of alcohols to aldehydes was acquired through aerobic oxidation using a well-known amino-oxy radical-functionalized MOF. In the same flask, a simple filtration of the radical MOF with mild heating of the solution completely altered the reaction media, providing radical scavenger-free conditions suitable for the autoxidation of the aldehydes formed in the first step to carboxylic acids. The mutually exclusive radical-catalyzed aerobic oxidation (the first step with MOF) and radical-inhibited autoxidation (the second step without MOF) are sequentially achieved in a one-pot manner. Overall, we demonstrate a powerful and efficient method for the sequential oxidation of alcohols to carboxylic acids by employing a readily functionalizable heterogeneous MOF. In addition, our MOF in-and-out method can be utilized in an environmentally friendly way for the oxidation of alcohols to carboxylic acids of industrial and economic value with broad functional group tolerance, including 2,5-furandicarboxylic acid and 1,4-benzenedicarboxylic acid, with good yield and reusability. Furthermore, MOF-TEMPO, as an antioxidative stabilizer, prevents the undesired oxidation of aldehydes, and the perfect "recoverability"of such a reactive MOF requires a re-evaluation of the advantages of MOFs from heterogeneity in catalytic and related applications.
- Kim, Seongwoo,Lee, Ha-Eun,Suh, Jong-Min,Lim, Mi Hee,Kim, Min
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p. 17573 - 17582
(2020/12/22)
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- Light and oxygen-enabled sodium trifluoromethanesulfinate-mediated selective oxidation of C-H bonds
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Visible light-induced organic reactions are important chemical transformations in organic chemistry, and their efficiency highly depends on suitable photocatalysts. However, the commonly used photocatalysts are precious transition-metal complexes and elaborate organic dyes, which hamper large-scale production due to high cost. Here, for the first time, we report a novel strategy: light and oxygen-enabled sodium trifluoromethanesulfinate-mediated selective oxidation of C-H bonds, allowing high-value-added aromatic ketones and carboxylic acids to be easily prepared in high-to-excellent yields using readily available alkyl arenes, methyl arenes and aldehydes as materials. The mechanistic investigations showed that the treatment of inexpensive and readily available sodium trifluoromethanesulfinate with oxygen under irradiation of light could in situ form a pentacoordinate sulfide intermediate as an efficient photosensitizer. The method represents a highly efficient, economical and environmentally friendly strategy, and the light and oxygen-enabled sodium trifluoromethanesulfinate photocatalytic system represents a breakthrough in photochemistry. This journal is
- Fu, Hua,Liu, Can,Liu, Yong,Yang, Haijun,Zhu, Xianjin
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supporting information
p. 4357 - 4363
(2020/07/14)
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- Pd(OAc)2 promoted bis-N-heterocyclic carbene-catalyzed oxidative transformation of aldehydes
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The bis-N-heterocyclic carbene-catalyzed (bis-NHC-catalyzed) oxidative transformation of aldehydes was successfully studied in water under air. The reaction rate increased through the use of Pd(OAc)2 as an additive. Notably, the catalytic system exhibited good tolerance toward aliphatic and aromatic aldehydes bearing halide and alkyl functional groups. In addition, gram-scale reaction was also tested in this study. The use of water and operational simplicity make this methodology environmentally benign and cost-effective.
- Yu, Ya-Han,Wang, Tsui,Chiu, Chien-Cheng,Lu, Ta-Jung,Lee, Dong-Sheng
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p. 202 - 205
(2019/11/28)
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- Oxidation of aromatic and aliphatic aldehydes to carboxylic acids by Geotrichum candidum aldehyde dehydrogenase
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Oxidation reaction is one of the most important and indispensable organic reactions, so that green and sustainable catalysts for oxidation are necessary to be developed. Herein, biocatalytic oxidation of aldehydes was investigated, resulted in the synthesis of both aromatic and aliphatic carboxylic acids using a Geotrichum candidum aldehyde dehydrogenase (GcALDH). Moreover, selective oxidation of dialdehydes to aldehydic acids by GcALDH was also successful.
- Hoshino, Tomoyasu,Yamabe, Emi,Hawari, Muhammad Arisyi,Tamura, Mayumi,Kanamaru, Shuji,Yoshida, Keisuke,Koesoema, Afifa Ayu,Matsuda, Tomoko
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- Catalytic C-H aerobic and oxidant-induced oxidation of alkylbenzenes (including toluene derivatives) over VO2+immobilized on core-shell Fe3O4?SiO2at room temperature in water
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Direct C-H bond oxidation of organic materials, and producing the necessary oxygenated compounds under mild conditions, has attracted increasing interest. The selective oxidation of various alkylbenzenes was carried out by means of a new catalyst containing VO2+ species supported on silica-coated Fe3O4 nanoparticles using t-butyl hydroperoxide as an oxidant at room temperature in H2O or solvent-free media. The chemical and structural characterization of the catalyst using several methods such as FTIR spectroscopy, XRD, FETEM, FESEM, SAED, EDX and XPS showed that VO2+ is covalently bonded to the silica surface. High selectivity and excellent conversion of various toluene derivatives, with less reactive aliphatic (sp3) C-H bonds, to related benzoic acids were quite noticeable. The aerobic oxygenation reaction of these alkylbenzenes was studied under the same conditions. All the results accompanied by sustainability of the inexpensive and simple magnetically separable heterogeneous catalyst proved the important criteria for commercial applications. This journal is
- Mohammadpour, Pegah,Safaei, Elham
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p. 23543 - 23553
(2020/07/14)
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- Photoinduced Carbon Tetrabromide Initiated Aerobic Oxidation of Substituted Toluenes to Carboxylic Acids
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A mild and metal-free procedure is reported for the aerobic oxidation of substituted toluenes to carboxylic acids by using CBr 4 as initiator under irradiation from a 400 nm blue light-emitting diode.
- Li, Xiaoqing,Xu, Xiangsheng,Yan, Xiaoyu,Yan, Xinhuan,Zhang, Guofu,Zheng, Kun
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p. 272 - 274
(2020/02/18)
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- Iodobenzene-catalyzed oxidative cleavage of olefins to carbonyl compounds
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A metal-free approach for the oxidative cleavage of carbon–carbon double bonds of olefins to carbonyl compounds was established by using oxidant m-CPBA and non-metallic organocatalyst PhI in toluene/H2O. A broad scope of aromatic olefins was used. All the reactions proceeded smoothly at 35 °C in short reaction time to furnish the respective mono- and double carbonyl compounds selectively in moderate to good yields.
- Du, Lele,Wang, Zechao,Wu, Junliang
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supporting information
(2020/07/20)
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- Selective Solvent-Free and Additive-Free Oxidation of Primary Benzylic C–H Bonds with O2 Catalyzed by the Combination of Metalloporphyrin with N-Hydroxyphthalimide
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Abstract: A protocol for solvent-free and additive-free oxidation of primary benzylic C–H bonds with O2 was presented through adjusting the combination of metalloporphyrins and NHPI as binary catalysts to overcome the deficiencies encountered in current oxidation systems. The effects of reaction temperature, porphyrin structure, central metal, catalyst loading and O2 pressure were investigated systematically. For the optimized combination of T(2-OCH3)PPCo and NHPI, all the primary benzylic C–H bonds could be functionalized efficiently and selectively at 120 °C and 1.0?MPa O2 with aromatic acids as the primary products. The selectivity towards aromatic acids could reach up to 70–95% in the conversion of more than 30% for most of the substrates possessing primary benzylic C–H bonds in the metalloporphyrin loading of 0.012% (mol/mol). And the superior performance of T(2-OCH3)PPCo among the metalloporphyrins investigated was mainly attributed to its high efficiency in charge transfer and fewer positive charges around central metal Co (II) which favored the adduction of O2 to cobalt (II) forming the high-valence metal-oxo complex followed by the production of phthalimide N-oxyl radical (PINO) and the initiation of the catalytic oxidation cycle. This work would provide not only an efficient protocol in utilization of hydrocarbons containing primary benzylic C–H bonds, but also a significant reference in the construction of more efficient C–H bonds oxidation systems. Graphic Abstract: The solvent-free and additive-free oxidation of primary benzylic C–H bonds with O2 was presented through adjusting the combination of metalloporphyrins and NHPI as binary catalysts, and the highest selectivity towards aromatic acid reached up to 95.1% with the conversion of 88.5% in the optimized combination of T(2-OCH3)PPCo and NHPI.[Figure not available: see fulltext.].
- Shen, Hai-Min,Qi, Bei,Hu, Meng-Yun,Liu, Lei,Ye, Hong-Liang,She, Yuan-Bin
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p. 3096 - 3111
(2020/04/29)
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- Metal-free Photocatalytic Aerobic Oxidative Cleavage of C?C Bonds in 1,2-Diols
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The preparation of carbonyl compounds by the aerobic oxidative cleavage of C?C bonds in 1,2-diols under mild reaction conditions is a very significant reaction and is widely employed in various scenarios. Avoiding the use of harmful stoichiometric oxidants and adopting a greener chemical process remain a challenge for this reaction to date. In this manuscript, a heterogeneous metal-free photocatalytic strategy without any additive was developed for aerobic oxidative cleavage of C?C bonds in 1,2-diols at ambient conditions with visible light. The reaction mechanism was further studied through a series of control experiments and density functional theory (DFT) calculations. In addition, the catalytic system showed a broad substrates scope, including aliphatic (linear or cyclic) 1,2-diols, benzylic, alkenyl 1,2-diols, and α-hydroxy acids (such as lactic acid). Thus, this strategy could serve as a method for the transformation of 1,2-diols to corresponding carbonyl compounds by the aerobic oxidative cleavage of C?C bonds.
- Zhu, Rui,Zhou, Gongyu,Teng, Jia-nan,Li, Xinglong,Fu, Yao
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p. 5248 - 5255
(2020/08/21)
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- Cr(VI) oxidation using cetylpicolinium dichromate: Kinetics of oxidation of benzaldehydes with a green protocol
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Oxidation kinetics of benzaldehyde and some of its ortho- and para-monosubstituted derivatives have been studied using cetylpicolinium dichromates, a class of novel phase transfer oxidants, in dichloromethane medium. The rate of reaction is first order with respect to oxidant and fractional order with respect to the substrates. The Michaelis–Menten type oxidation was observed with respect to the substrates. Benzaldehydes are found to be oxidized to their corresponding acids. The mechanism of oxidation reaction has been suggested based on the solvent isotope effect, Hammett plot, and thermodynamic study. The solvent isotope effect (kCHCl3/kCDCl3=?1.57) indicates the involvement of hydrogen exchange with the medium during oxidation reactions. A strong influence of specific solute–solvent interactions on the rate of the reaction is observed. Both the electron-withdrawing and electron-releasing substituents on the substrates accelerate the rate of reaction.
- Priyadarshini, Supriya,Dash, Sukalyan
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p. 105 - 111
(2018/11/27)
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- Synthesis method of benzoic acid compounds
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The invention discloses a photocatalytic oxidation synthesis method of benzoic acid compounds, and the photocatalytic oxidation synthesis method comprises the following specific steps: mixing and dissolving toluene compounds and a catalyst in a solvent, reacting for 24-60h in the presence of an oxidant under the conditions of 350-460 nm LED illumination and a temperature of 20-80 DEG C, and performing post-treatment on the reaction liquid to obtain the benzoic acid compounds. The photocatalytic oxidation synthesis method has the advantages of no need of metal catalysts, simple operation and mild reaction conditions; oxygen is used as an oxidant, and the photocatalytic oxidation synthesis method has high atom economy, cheap reagent and environmental protection. The photocatalytic oxidationsynthesis method has good substrate applicability, and various substituents can realize the synthesis of corresponding benzoic acid compounds.
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Paragraph 0122; 0123; 0124; 0125
(2019/12/25)
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- Preparation method of substituted benzoic acid compounds
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The invention relates to the field of production of chemical products, in particular to a preparation method of substituted benzoic acid compounds represented as general formula (II) in the description. The preparation method comprises steps as follows: corresponding substituted alkyl benzene represented as general formula (I) in the description is taken as a raw material, dilute nitric acid is taken as a reaction medium, oxygen is taken as an oxidant, an imide compound with a structure represented as formula (III) in the description or formula (IV) in the description is selected as a catalyst, all materials are subjected to catalytic oxidation in a high-pressure kettle, and substituted benzoic acid is prepared, wherein R1 is C1-C4 alkyl and R2 is halogen, nitryl, C1-C4 alkyl, methoxyl andtrifluoromethyl. The green preparation method of the substituted benzoic acid compounds is provided and has the advantages of high production purity, simple preparation, mild reaction conditions, simple aftertreatment, low cost and no pollution.
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Paragraph 0048; 0049
(2019/05/08)
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- Selective oxidation method for toluene compounds
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The invention discloses a selective oxidation method for toluene compounds. The method comprises the following steps: 1, putting a toluene compound represented by a formula (I) shown in the specification, a metalloporphyrin catalyst, an oxidant and a dispersing agent into a ball milling tank, sealing the ball milling tank, carrying out ball milling for 3-24 hours at room temperature and the rotating speed of 100-800 rpm, stopping ball milling once every 1-3 hours in the ball milling process, discharging gas in the ball milling tank, and after the reaction is finished, carrying out post-treatment on the reaction mixture to obtain a product benzoic acid compound represented by a formula (II) shown in the specification. Oxidation conversion of methylbenzene and derivatives thereof is achievedthrough solid-phase ball milling, the reaction mode is novel, the operation is convenient, and the energy consumption is low; an organic solvent and other auxiliaries are not needed, so that use of toxic and harmful organic reagents is effectively avoided, and the method is green and environmentally friendly; the peroxide content is low, and the safety coefficient is high; and benzoic acid and derivatives thereof have high selectivity and meet the social requirements of a green chemical process, an environmental compatibility chemical process and a biological compatibility chemical process inthe prior art.
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Paragraph 0122; 0123
(2019/12/25)
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- Nitrogen Dioxide Catalyzed Aerobic Oxidative Cleavage of C(OH)–C Bonds of Secondary Alcohols to Produce Acids
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Stable organic nitroxyl radicals are an important class of catalysts for oxidation reactions, but their wide applications are hindered by their steric hinderance, high cost, complex operation, and separation procedures. Herein, NO2 in DMSO is shown to effectively catalyze the aerobic oxidative cleavage of C(OH)?C bonds to form a carboxylic group, and NO2 was generated in situ by decomposition of nitrates. A diverse range of secondary alcohols were selectively converted into acids in excellent yields in this transition-metal-free system without any additives. Preliminary results also indicate its applicability to depolymerize recalcitrant macromolecular lignin. Detail studies revealed that NO2 from nitrates promoted the reaction, and NO2 served as hydrogen acceptor and radical initiator for the tandem oxidative reaction.
- Liu, Mingyang,Zhang, Zhanrong,Song, Jinliang,Liu, Shuaishuai,Liu, Huizhen,Han, Buxing
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supporting information
p. 17393 - 17398
(2019/11/11)
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- CO2 activation by electrogenerated divalent samarium for aryl halide carboxylation
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The reductive carboxylation of aryl halides has been investigated using a samarium electrode as a sacrificial anode to yield the corresponding benzoic acids, providing a smooth strategy for CO2 activation. Carboxylation occurred after an efficient reduction of carbon dioxide mediated by an electrogenerated Sm(ii)-complex acting as a strong monoelectronic reductive reagent.
- Bazzi, Sakna,Le Duc, Ga?tan,Schulz, Emmanuelle,Gosmini, Corinne,Mellah, Mohamed
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supporting information
p. 8546 - 8550
(2019/10/02)
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- O -Hydroxycinnamate for sequential photouncaging of two different functional groups and its application in releasing cosmeceuticals
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We demonstrated a new approach for the sequential photouncaging of two different functional groups from o-hydroxycinnamate. The second caged molecule initially remains in the locked state and is released only after attaining its unlocked state upon in situ generation of the second phototrigger, i.e., coumarin, thereby leading to the sequential release of alcohol and carboxylic acid. We have utilised the above strategy for the controlled release of cosmeceutical agents.
- Paul, Amrita,Bera, Manoranjan,Gupta, Prakhar,Singh, N. D. Pradeep
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supporting information
p. 7689 - 7693
(2019/08/30)
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- Copper Catalyzed Oxidative C-C Bond Cleavage of 1,2-Diketones: A Divergent Approach to 1,8-Naphthalimides, Biphenyl-2,2′-dicarboxamides, and N-Heterocyclic Amides
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We report here a simple and efficient copper catalyzed oxidative C-C bond cleavage of stable aromatic cyclic-fused and acyclic 1,2-diketones to deliver amides and imides in high yields. This newly developed protocol provides an excellent tool to transform structurally different 1,2-diketones into different products under the same reaction conditions. The key synthetic features of this methodology are the formation of 1,8-naphthalimides and biphenyl-2,2′-dicarboxamide motifs in high yields. The fluorescent studies of 1,8-naphthalimide derivatives were also carried out in order to show the potential application of these scaffolds.
- Sakhare, Priyanka R.,Subramanian, Parthasarathi,Kaliappan, Krishna P.
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p. 2112 - 2125
(2019/02/14)
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- A Three-Phase Four-Component Coupling Reaction: Selective Synthesis of o-Chloro Benzoates by KCl, Arynes, CO2, and Chloroalkanes
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A transition-metal-free three-phase four-component coupling reaction (3P-4CR) involving KCl, arynes, chloroalkanes and CO2 has been reported for the first time, enabling the incorporation of both chloro and CO2 into an aryne simultaneously. The reactions for the synthesis of different types of o-chloro benzoates can be selectively modulated by the chloroalkane utilized. The corresponding products can be alternatively transformed for postsynthetic functionalizations conveniently.
- Jiang, Huanfeng,Zhang, Yu,Xiong, Wenfang,Cen, Jinghe,Wang, Lu,Cheng, Ruixiang,Qi, Chaorong,Wu, Wanqing
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supporting information
p. 345 - 349
(2019/01/24)
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- Aqueous Flow Hydroxycarbonylation of Aryl Halides Catalyzed by an Amphiphilic Polymer-Supported Palladium-Diphenylphosphine Catalyst
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An aqueous continuous-flow reaction system is developed for the palladium-catalyzed hydroxycarbonylation of aryl halides. Flow hydroxycarbonylation of aryl halides in aqueous solution proceeds efficiently in a flow reactor containing a palladium-diphenylphosphine complex immobilized on an amphiphilic polystyrene-poly(ethylene glycol) resin to give the corresponding benzoic acids in excellent yields.
- Osako, Takao,Kaiser, Reinhard,Torii, Kaoru,Uozumi, Yasuhiro
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p. 961 - 966
(2019/05/10)
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- Sodium copper chlorophyllin catalyzed chemoselective oxidation of benzylic alcohols and diarylmethanes in water
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We report the highly efficient and chemoselective oxidation of benzylic alcohols catalyzed by sodium copper chlorophyllin in water, producing corresponding arylcarbonyl compounds. Importantly, the catalytic system exhibits a wide substrate scope and high functional group tolerance. Moreover, secondary alcohols and even diarylmethanes were smoothly oxidized to the desired aryl ketones with excellent yields.
- Liu, Shi-juan,Zhang, Miao,Lu, Rong,Li, Xiu-ying,Che, Guang-bo
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- Unusual synthesis of azines and their oxidative degradation to carboxylic acid using iodobenzene diacetate
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Reaction of 3-hydrazonobutan-2-one oxime with aromatic aldehydes resulted in the formation of 1,2-bis(arylidene)hydrazine commonly referred as azine as an unexpected product, instead of expected product 3-(aryl)methylenehydrazonobutan-2-one oxime, which were subsequently oxidized to corresponding aromatic acids with an ecofriendly oxidizing agent iodobenzene diacetate. Azines and carboxylic acids were characterized by IR and NMR (1H, 13C, HMBC, and HMQC) studies.
- Sumran, Garima,Aggarwal, Ranjana,Hooda, Mona,Sanz, Dionisia,Claramunt, Rosa M.
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p. 439 - 446
(2018/02/06)
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- A biocatalytic method for the chemoselective aerobic oxidation of aldehydes to carboxylic acids
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Herein, we present a study on the oxidation of aldehydes to carboxylic acids using three recombinant aldehyde dehydrogenases (ALDHs). The ALDHs were used in purified form with a nicotinamide oxidase (NOx), which recycles the catalytic NAD+ at the expense of dioxygen (air at atmospheric pressure). The reaction was studied also with lyophilised whole cell as well as resting cell biocatalysts for more convenient practical application. The optimised biocatalytic oxidation runs in phosphate buffer at pH 8.5 and at 40 °C. From a set of sixty-one aliphatic, aryl-Aliphatic, benzylic, hetero-Aromatic and bicyclic aldehydes, fifty were converted with elevated yield (up to >99%). The exceptions were a few ortho-substituted benzaldehydes, bicyclic heteroaromatic aldehydes and 2-phenylpropanal. In all cases, the expected carboxylic acid was shown to be the only product (>99% chemoselectivity). Other oxidisable functionalities within the same molecule (e.g. hydroxyl, alkene, and heteroaromatic nitrogen or sulphur atoms) remained untouched. The reaction was scaled for the oxidation of 5-(hydroxymethyl)furfural (2 g), a bio-based starting material, to afford 5-(hydroxymethyl)furoic acid in 61% isolated yield. The new biocatalytic method avoids the use of toxic or unsafe oxidants, strong acids or bases, or undesired solvents. It shows applicability across a wide range of substrates, and retains perfect chemoselectivity. Alternative oxidisable groups were not converted, and other classical side-reactions (e.g. halogenation of unsaturated functionalities, Dakin-Type oxidation) did not occur. In comparison to other established enzymatic methods such as the use of oxidases (where the concomitant oxidation of alcohols and aldehydes is common), ALDHs offer greatly improved selectivity.
- Knaus, Tanja,Tseliou, Vasilis,Humphreys, Luke D.,Scrutton, Nigel S.,Mutti, Francesco G.
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supporting information
p. 3931 - 3943
(2018/09/11)
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- The Cu(I)- and HNO3-catalyzed oxidation of substituted toluenes to the benzoic acid based on NOx recycling
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Based on the recycling of NOx, the Cu(I)- and HNO3-catalyzed oxidation of 2-chloro-4-(methylsulfonyl)toluene to 2-chloro-4-(methylsulfonyl)benzoic acid has been developed with an excellent yield of 84.2% and a purity of 99.7%. The optimized reaction conditions (160?°C, oxygen pressure 1.5?MPa, HNO3 concentration 25?wt%, HNO3: substrate 0.5:1) use 1.0?mol% CuI as catalyst. The dosage of HNO3 in the new process is only 25% of the stoichiometric amount and 12.5% of the amount of the traditional process. The NOx emission is 5% amount of the traditional process. The oxidation of several additional toluene derivatives with comparable yields demonstrates the generality to these reaction conditions.
- Wei, Mengyi,Qian, Chao,Chen, Xinzhi
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- Cobalt/N-Hydroxyphthalimide(NHPI)-Catalyzed Aerobic Oxidation of Hydrocarbons with Ionic Liquid Additive
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A highly efficient and solvent-free system of cobalt/NHPI-catalyzed aerobic oxidation of hydrocarbons was developed using imidazolium-based ionic liquid (IL) as an additive. These amphipathic ILs were found self-assemble at the interface between the organic hydrocarbons and the aqueous phase of catalyst combination (Co/NHPI), with forming a solution of reversed multilamellar vesicles for catalysis. The initial reaction rate was influenced by both the composition of microdomains and the structure of IL launched. Consequently, a proper water content (χH2O) of wet IL was requisite to reach the optimum reactivity. Besides, the interfacial boundary between aqueous and organic phase composed by C2-alkylated imidazolium ILs, such as [bdmim]SbF6 and [C12dmim]SbF6, not only has ternary aggregates (hydrocarbons/IL/H2O) of higher stability but renders O2 a faster diffusion rate and higher concentration, thereby offering a high reactivity of the protocol towards hydrocarbon oxidation.
- Mahmood, Sajid,Xu, Bao-Hua,Ren, Tian-Lu,Zhang, Zhi-Bo,Liu, Xiao-Min,Zhang, Suo-Jiang
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- Catalytic Promiscuity of Galactose Oxidase: A Mild Synthesis of Nitriles from Alcohols, Air, and Ammonia
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We report an unprecedented catalytically promiscuous activity of the copper-dependent enzyme galactose oxidase. The enzyme catalyses the one-pot conversion of alcohols into the related nitriles under mild reaction conditions in ammonium buffer, consuming ammonia as the source of nitrogen and dioxygen (from air at atmospheric pressure) as the only oxidant. Thus, this green method does not require either cyanide salts, toxic metals, or undesired oxidants in stoichiometric amounts. The substrate scope of the reaction includes benzyl and cinnamyl alcohols as well as 4- and 3-pyridylmethanol, giving access to valuable chemical compounds. The oxidation proceeds through oxidation from alcohol to aldehyde, in situ imine formation, and final direct oxidation to nitrile.
- Vilím, Jan,Knaus, Tanja,Mutti, Francesco G.
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supporting information
p. 14240 - 14244
(2018/10/15)
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- I2/Fe(NO3)3·9H2O-catalyzed oxidative synthesis of aryl carboxylic acids from aryl alkyl ketones and secondary benzylic alcohols
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An interesting and convenient procedure for the oxidative transformation of aryl alkyl ketones and secondary benzylic alcohols to aryl carboxylic acids has been developed. By using iodine and Fe(NO3)3·9H2O as the catalysts, DMSO and oxygen as the oxidants, the desired aryl carboxylic acids were synthesized in moderate to excellent yields (up to 91%).
- Xu, Liang,Chen, Yingying,Shen, Zhenlu,Wang, Yuru,Li, Meichao
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p. 4349 - 4354
(2018/11/03)
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- Oxidative C-C Bond Cleavage for the Synthesis of Aryl Carboxylic Acids from Aryl Alkyl Ketones
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A metal-free and one-pot two-step synthesis of aryl carboxylic acids from aryl alkyl ketones has been achieved. The reactions were performed with iodine as the catalyst, DMSO and TBHP as the oxidants. Under the optimal reaction conditions, a number of aryl alkyl ketones could be converted into their corresponding aryl carboxylic acids in good to excellent yields (up to 94%).
- Xu, Liang,Wang, Shengpeng,Chen, Bajin,Li, Meichao,Hu, Xinquan,Hu, Baoxiang,Jin, Liqun,Sun, Nan,Shen, Zhenlu
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p. 1505 - 1509
(2018/05/25)
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- Urea-based amphiphilic porous organic polymer-supported palladium as a reusable catalyst for Suzuki–Miyaura coupling and hydroxycarbonylation reactions in water
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The development of environmentally friendly heterogeneous catalysts for organic reactions in water is becoming of growing importance for the development of sustainable processes. In this work, a porous organic polymer-supported palladium catalyst (Pd@UPOP-1) was successfully fabricated from 3,3′-diaminobenzidine and methylenediphenyl diisocyanate through a facile urea-forming condensation reaction. The structure and composition of the catalyst were characterized using several physicochemical methods. Pd@UPOP-1 was found to possess good porous structure and excellent amphiphilicity. Under mild reaction conditions, the catalyst showed excellent catalytic activity and good substrate compatibility for the Suzuki–Miyaura coupling reaction of aryl bromides, as well as the hydroxycarbonylation reaction of aryl iodides. In addition, the catalyst could be used for several consecutive recycles in both cases.
- Lei, Yizhu,Lan, Guosong,Zhu, Dajian,Wang, Renshu,Zhou, Xiao-Yu,Li, Guangxing
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- Catalytic oxidation synthesis method of aryl formic acid
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The invention discloses a catalytic oxidation synthesis method of aryl formic acid. According to the method, aryl alkyl ketone is used as a reaction substrate, iodine is used as a catalyst, and dimethyl sulfoxide (DMSO) is taken as an oxidizing agent; the method comprises the steps of adding the reaction substrate into chlorobenzene, and carrying out a reaction for 2-4h at the temperature of 110-135 DEG C; after that, cooling reaction liquid to the room temperature, adding another oxidizing agent, i.e., t-butylhydroperoxide (TBHP), continuously carrying out a reaction at the temperature of 110-135 DEG C, and separating after the reaction is finished so as to obtain the aryl formic acid. The method provided by the invention avoids the use of a transition metal catalyst, thus reducing the consumption of toxic and harmful additives; the reaction substrate is wide in application scope.
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Paragraph 0082; 0083
(2018/07/30)
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- Method for preparing aryl formic acid by adopting aryl alkyl ketone as raw material
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The invention discloses a method for preparing aryl formic acid by adopting aryl alkyl ketone as a raw material. The method is characterized in that: aryl alkyl ketone is used as a reaction substrate,iodine and Fe(NO3)3.9H2O are used catalysts to react for 8 to 16 hours in dimethyl sulfoxide at the temperature 110 to 140 DEG C in an oxygen atmosphere of one barometric pressure, and after the reaction is ended, the reactant is separated to obtain the aryl formic acid. According to the synthetic method of the invention, the environment-friendly iron catalyst is used; the environment-friendly green oxidant oxygen is used; the reaction is performed at the normal pressure, and no pressurizing device is needed; and the application range of the reaction substrate is wide.
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Paragraph 0081; 0082
(2019/01/08)
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- Transition metal free one pot synthesis of aryl carboxylic acids via dehomologative oxidation of styrenes
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Iodine/NaOH-catalyzed one-pot dehomologative oxidation of styrenes to aryl carboxylic acids has been reported. A wide range of carboxylic acids are obtained using iodine (I2) as a catalyst, tert-butyl hydroperoxide (TBHP) as an oxidant and sodium hydroxide (NaOH) as a base. This reliable conversion involves dehomologation of styrene to aromatic aldehyde which on subsequent oxidation affords aryl carboxylic acid. This protocol was used for gram-scale synthesis as it is free from chromatographic purification. This is the first report for the oxidative transformation of styrenes into aryl carboxylic acids under transition metal-free conditions.
- Patil, Bhausaheb N.,Sathe, Pratima A.,Parade, Babasao S.,Vadagaonkar, Kamlesh S.,Chaskar, Atul C.
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supporting information
p. 4340 - 4343
(2018/11/06)
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- Synthesis of a polymer–ruthenium complex Ru(pbbp)(pydic) and its catalysis in the oxidation of secondary alcohols with TBHP as oxidant
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A polymer–ruthenium complex Ru(pbbp)(pydic) was synthesized from the reaction of poly-2,6-bis(benzimidazolyl)pyridine (pbbp) with RuCl3 and disodium pyridine-2,6-dicarboxylate (pydic). The Ru(pbbp)(pydic) was characterized thoroughly by spectroscopic methods. ICP analysis revealed that the percentage of complexation of 2,6-bis(benzimidazolyl)pyridine unit in pbbp was about 83%. The complex was tested as a heterogeneous catalyst for the oxidation of secondary alcohols to their corresponding carbonyl compounds in solvent-free conditions using aqueous tert-butyl hydroperoxide as oxidant. The developed catalytic system exhibited high activity and broad functional group compatibility, allowing a variety of secondary alcohols, including substituted secondary benzylic alcohols and secondary aliphatic ones, to be oxidized to the corresponding ketones in high yields. This Ru(pbbp)(pydic) could be recycled for several times, but it dissolved in part in the reaction mixture during the catalytic run leading to gradual deactivation of the catalyst with repeated runs.
- Zhang, Yuecheng,Chu, Ruosi,Zhang, Hongyu,Zhao, Jiquan
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p. 105 - 116
(2017/02/23)
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- Catalyst-free aerobic oxidation of aldehydes into acids in water under mild conditions
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The first example of catalyst-free aerobic oxidation of aldehydes in water under respective acidic, neutral and alkaline conditions was developed. The sole oxidant is molecular oxygen of 1 atmosphere and reactions can proceed under extremely mild conditions. This procedure covers a wide range of aldehydes, and operates easily. No additives and catalysts were required for this purpose, and most of the aldehydes can be converted to their corresponding carboxylic acids with good to excellent yields, in addition, no side-product formation could be observed during or after the reactions. To well illustrate why the oxidation rate becomes fast firstly and then slows with increased temperatures, five control reactions were carried out and a Fe3+/Fe2+ recycling system was introduced to facilitate the aldehyde oxidation rate. The generality of this method offers the potential for industrial aldehyde-containing waste water treatment.
- Zhang, Yue,Cheng, Yujia,Cai, Huizhuo,He, Shaopo,Shan, Qiheng,Zhao, Hongwei,Chen, Yiping,Wang, Bo
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supporting information
p. 5708 - 5713
(2017/12/06)
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- Transition-Metal- and Halogen-Free Oxidation of Benzylic sp 3 C-H Bonds to Carbonyl Groups Using Potassium Persulfate
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Aryl carbonyl compounds including acetophenones, benzophenones, imides, and benzoic acids are prepared from benzyl substrates using potassium persulfate as oxidant with catalytic pyridine in acetonitrile under mild conditions. Neither transition metals nor halogens are involved in the reactions.
- Hu, Yixin,Zhou, Lihong,Lu, Wenjun
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supporting information
p. 4007 - 4016
(2017/08/29)
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- Iron(II) and copper(II) phthalocyanine-catalyzed synthesis of 2-nitro-4-methylsulfonylbenzoic acid under mild conditions
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Abstract : A novel method was?developed?to produce 2-nitro-4-methylsulfonylbenzoic acid (NMSBA) from the oxidation of 2-nitro-4-methylsulfonyltoluene (NMST) by oxygen catalyzed by iron(II) phthalocyanine (FePc) and copper(II) phthalocyanine (CuPc). The order of activity for oxidation of NMST was found to be: FePc > CuPc. Meanwhile, major reaction parameters such as concentrations of catalyst and NaOH, reaction temperature and oxygen pressure have been investigated. Through optimization of the reaction parameters, the highest yield of NMSBA and conversion of NMST (up to 53%, 89.3%, respectively) were achieved with oxygen (2.0 MPa), FePc (1.0×10-4molL-1), NaOH (0.6molL-1), in methanol at 55°C for 8 h. A plausible mechanism for this catalytic process is proposed which involved deprotonation and radical pathways. Graphical Abstract: A novel method to produce 2-nitro-4-methylsulfonylbenzoic acid (NMSBA) from the oxidation of 2-nitro-4-methylsulfonyltoluene (NMST) by oxygen catalyzed by iron(II) phthalocyanine (FePc) and copper(II) phthalocyanine (CuPc) has been developed. The reaction parameters and mechanism were studied. The catalytic system will be readily applicable to large-scale production of NMSBA. [Figure not available: see fulltext.].
- Huang, Cheng,Liu, Rui,Zhang, Caiting,Cheng, Qipeng,Zhu, Hongjun
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p. 1587 - 1594
(2017/11/03)
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- Iron(II) phthalocyanine immobilized SBA-15 catalysts: Preparation, characterization and application for toluene selective aerobic oxidation
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Iron(II) tetracarboxyl phthalocyanine (tcFePc) grafted onto amino-functionalized SBA-15 catalysts for selective oxidation of toluene by oxygen and N-hydroxyphthalimide (NHPI) were studied under mild conditions. The catalysts were characterized by nitrogen adsorption measurements, X-ray diffraction, element analyses, transmission electron microscopy, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. Their catalytic performance depended on the isolated amino group and tcFePc contents, which induced the surface composition and porosity of the catalysts. Less isolated amino groups (2.4 μmol/m2) and more grafted tcFePc (20 wt%) facilitate the oxidation efficiency of toluene to benzoic acid. Meanwhile, more isolated amino groups (3.8 μmol/m2) and less grafted tcFePc (11 wt%) weaken the oxidation activity of toluene and tend to form benzaldehyde. Reaction parameters, reaction scope and catalyst reusability were also investigated over 20 wt% tcFePc@NH2-SBA-15-3. Moreover, a plausible pathway for this catalytic process was proposed to involve a radical mechanism.
- Huang, Cheng,Liu, Rui,Yang, Wenyu,Zhang, Caiting,Zhu, Hongjun
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supporting information
p. 307 - 315
(2017/08/26)
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- SO2F2-Mediated One-Pot Synthesis of Aryl Carboxylic Acids and Esters from Phenols through a Pd-Catalyzed Insertion of Carbon Monoxide
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A one-pot Pd-catalyzed carbonylation of phenols into their corresponding aryl carboxylic acids and esters through the insertion of carbon monoxide has been developed. This procedure offers a direct synthesis of aryl carboxylic acids and esters from inexpensive and abundant starting materials (phenols, SO2F2 and CO) under mild conditions. This method tolerates a broad range of functional groups and is also applicable for the modification of complicated natural products.
- Fang, Wan-Yin,Leng, Jing,Qin, Hua-Li
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supporting information
p. 2323 - 2331
(2017/09/06)
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