- A Green Route to Produce Adipic Acid on TiO2–Fe2O3 Nanocomposites
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In this work, we study cyclohexene oxidation by molecular oxygen on doped-TiO2. The improvement of the oxidizing capacity of titanium oxide by doping with iron oxide at different molar ratios is checked. All materials with different molar ratios (Ti/Fe = 9, 4, and 2) are prepared by the sol–gel method and fully characterized by ICP, XRD, SEM, DR/UV–vis, IR, and N2 adsorption/desorption. The results show that iron is successfully incorporated into the titanium matrix but the incorporated amount is limited. In catalytic tests, improved activity is noticed while using TiO2 in the presence of Fe2O3, which is due the improved oxidation. Conversion in the range of 21–42% depending on the presence of iron oxide was obtained with excellent yield of adipic acid (97% selectivity).
- Ameur, Nawal,Bachir, Redouane,Bedrane, Sumeya,Choukchou-Braham, Abderrahim
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- Optimization of adiponitrile hydrolysis in subcritical water using an orthogonal array design
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A study of the hydrolysis of adiponitrile (ADN) was performed in subcritical water to research the dependence on experimental conditions. An L25(56) orthogonal array design (OAD) with six factors at five levels using statistical analysis was employed to optimize the experimental conditions for each product in which the interactions between the variables were temporarily neglected. The six factors were adiponitrile concentration (ADN c, wt%), temperature (T), time (t h), percentage of additives (reactant/additive, wt/wt%), additives (A), and pressure (p, MPa). The effects of these parameters were investigated using the analysis of variance (ANOVA) to determine the relationship between experimental conditions and yield levels of different products. The results showed that (ADN c) and T had a significant influence on the yields of adipamide, adipamic acid, and adipic acid at p0.05. Time was the statistically significant factor for the yield of 5-cyanovalermic acid at p0.05 and (ADN c) was the significant factor for the yield of 5-cyanovaleramide at p0.1. Finally, five supplementary experiments were conducted under optimized conditions predicted by the Taguchi method; the results showed that the yield obtained of each product was no lower than that of the highest in the 25 experiments. Carbon balance was calculated to demonstrate the validity of the experimental technique and the reliability of the results. Based on the experimental results, a possible reaction mechanism was proposed.
- Duan, Peigao,Wang, Yuanyuan,Yang, Yan,Dai, Liyi
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- A Novel Reaction of Some Enolisable Ketones not involving the Rate-determining Enolisation Step. Kinetics of the Reaction of Ketones with Trichloroisocyanuric Acid in the Presence of Added Chloride Ion in Acid Medium
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Kinetics of the reaction between some enolisable ketones (S) and trichloroisocyanuric acid (TCICA) in aqueous acid-acetic acid medium at 35 deg C follow pseudo-zero-order and pseudo-first-order disappearance of 0 in the absence and the presence of added Cl-, respectively.The rate constants for the latter system exhibit a linear dependence each on 0 and +>, and an increasing and limiting dependence on added ->.The results are interpreted in terms of probable mechanisms involving (i) rate-determining enol formation from the conjugate acid of the ketone (SH+) in the absence of added Cl- and (ii) rate-determining interaction of SH+ with the most effective molecular chlorine species produced by the hydrolysis of TCICA (rather than a rate-determining interaction of enol with Cl2) in the presence of added Cl-, prior to the rapid steps of product formation.
- Radhakrishnamurti, Patapati Subu,Rath, Nabeen Kumar,Panda, Rama Krushna
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- One pot oxidative cleavage of cyclohexene to adipic acid using silver tungstate nano-rods in a Br?nsted acidic ionic liquid
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A green and facile method for oxidation of cyclohexene to adipic acid is introduced using 30% H2O2 as oxidant. The catalytic system comprises small amounts of Ag2WO4 nano-rods and a Br?nsted acidic ionic liquid (1,2-dimethyl-3-dodecylidazolium hydrogensulfate).
- Vafaeezadeh, Majid,Mahmoodi Hashemi, Mohammad
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- PHOTOREACTION OF 2-BENZOYLCYCLOHEXANONES ON A SILICA GEL SURFACE: DEVIATION FROM THEIR SOLUTION PHOTOCHEMISTRY
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On irradiation on a dry silica gel surface, 2-benzoylcyclohexanones which have the lowest n, ?* state and are devoid of methyl substituents on their cyclohexanone rings, undergo an oxidative cleavage to give adipic acid and substituted benzoic acid along with the Norrish Type II product.Irradiation of 2-chlorocyclohexanone and cyclohexane-1,2-dione on silica gel gives adipic acid.The cyclohexanoyl radical on the surface, which is produced from the α-cleavage of the 2-benzoyl group of the 2-benzoylcyclohexanones or the cleavage of the C-Cl bond of 2-chlorocyclohexanone, is suggested as the precursor of adipic acid; the radical is probably converted into cyclohexane-1,2-dione, which undergoes a secondary photoreaction to give adipic acid on the surface.
- Hasegawa, Tadashi,Imada, Manabu,Yoshioka, Michikazu
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- Synthesis of AgWCNx Nanocomposites for the One-Step Conversion of Cyclohexene to Adipic Acid and Its Mechanistic Studies
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A novel catalyst composed of silver nanoparticles grafted on WCNx has been prepared by using a facile pH-adjusted method. The material reported in this study presents a non-mineral acid route for the synthesis of the industrially significant monomer adipic acid through the selective oxidation of cyclohexene. Ag has been stabilized in the hydrophobic matrix during the formation of the mesoporous silica material by using aniline as stabilizing agent. A cyclohexene conversion of 92.2 % with 96.2 % selectivity for adipic acid was observed with the AgWCNx-2 catalyst, therefore, the AgWCNx catalyst was found to be efficient for the direct conversion to adipic acid with respect to their monometallic counterparts. The energy profile diagrams for each reaction path by using the AgWCNx catalyst were studied along with their monometallic counterparts by using the Gaussian 09 package. The reported material can avoid the use of harmful phase-transfer catalysts (PTC) and/or chlorinated additives, which are two among other benefits of the reported work.
- Goyal, Reena,Sameer, Siddharth,Sarkar, Bipul,Bag, Arijit,Singhal, Nikita,Bordoloi, Ankur
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- Oxidation of cyclohexane to adipic acid using Fe-porphyrin as a biomimetic catalyst
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A one-pot oxidation from cyclohexane to adipic acid has been developed, catalyzed by Fe-porphyrin in the presence of molecular oxygen without any additives. When the reaction temperature is 140°C, oxygen pressure is 2.5 MPa, concentration of catalyst is 1.33 × 10-5 mol %, and reaction time is 8 h, the yield of adipic acid reaches 21.4%. A turnover number of about 24582 is thus far the highest one among those reported for the direct oxidation from cyclohexane to adipic acid.
- Yuan, Ying,Ji, Hongbing,Chen, Yixia,Han, Yong,Song, Xufeng,She, Yuanbin,Zhong, Rugang
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- The primary stages of polyoxomolybdate catalyzed cyclohexanone oxidation by hydrogen peroxide as investigated by in situ NMR. Substrate activation and evolution of the working catalyst
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The catalytic process of cyclohexanone oxidation by hydrogen peroxide was investigated using in situ NMR spectroscopy in real working conditions. The behavior of the Keggin heteropolyacid H3PMo12O40, used as a model catalyst, was explored before and after adding the oxidant agent. This study revealed the evolution pathways to different reduced states of H3PMo12O40 and its reversible transformation into peroxomolybdate complexes. These latter were identified as the active species for the adipic acid formation, while the acid function of the catalyst was found important for the substrate activation via ketonic-enolic tautomerism. The oxidative mechanism of the cyclohexanone was described through three successive steps to produce adipic acid.
- Amitouche, Dahbia,Haouas, Mohamed,Mazari, Tassadit,Mouanni, Sihem,Canioni, Romain,Rabia, Chérifa,Cadot, Emmanuel,Marchal-Roch, Catherine
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- Liquid-phase catalytic oxidation of C6-C7 cycloolefins into carboxylic acids in a pseudohomogeneous system
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Liquid-phase oxidation of cyclohexene, methylcyclohexene isomers, and norbornene with a 30% solution of hydrogen peroxide in a pseudohomogeneous system involving highly dispersed compounds of Group-VIb and -VIIIb metals supported by nanosize carbon particles was studied.
- Alimardanov, Kh. M.,Sadygov,Garibov,Abbasov,Abdullaeva, M. Ya.,Dzhafarova
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- Oxidation of cyclohexene into adipic acid in aqueous dispersions of mesoporous oxides with built-in catalytical sites
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Reactant incompatibility is a common problem in organic chemistry. This study investigates the use of concentrated aqueous dispersions of mesoporous oxides to overcome incompatibility. Oxidation of cyclohexene into adipic acid using aqueous hydrogen peroxide as oxidant has been performed in a range of ordered and disordered mesoporous materials. The different mesoporous oxides have been characterised with diffraction techniques (XRD and SAXS), electron microscopy (TEM and SEM) and nitrogen adsorption isotherms (BET and BJH methods). The catalyst used in the reaction was either soluble sodium tungstate added to a reaction system based on mesoporous silica, alumina or a silica/alumina mixture; or a catalytic oxide, tungsten oxide or titania, present in the framework of the mesoporous material. Tungsten oxide, either used as the sole oxide material or as a mixed oxide with silica turned out to be very efficient and gave almost quantitative yield of adipic acid. A major advantage with having the catalyst chemically incorporated in the walls of the porous material is that it can be easily reused. The results from recycling experiments show that the catalytic activity is retained.
- Bohstroem, Zebastian,Rico-Lattes, Isabelle,Holmberg, Krister
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- Design of silica supported task-specific ionic liquid catalyst system for oxidation of cyclohexene to adipic acid with 30% H2O2
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1-Butyl-3-methylimidazolium tungstate ([BMIm]2WO4) ionic liquid supported onto silica sulphamic acid demonstrated desirable performance for oxidation of cyclohexene to adipic acid. Simple experimental procedure, easy product isolation, catalyst recovery and reusability are some attractive features of this protocol.
- Vafaeezadeh, Majid,Hashemi, Mohammad Mahmoodi,Shakourian-Fard, Mehdi
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- Synthesis of adipic acid oxidized by h2o2-silicotungstic acid under ultrasonication
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A green synthesis of adipic acid from cyclohexene oxidized by H2O2-silicotungstic acid was carried out in 92 % yields at 30 C within 4 h under ultrasound irradiation.
- Lin, Zhi-Ping,Wan, Li
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- Alkene hydrogenation activity of enoate reductases for an environmentally benign biosynthesis of adipic acid
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Adipic acid, a precursor for Nylon-6,6 polymer, is one of the most important commodity chemicals, which is currently produced from petroleum. The biosynthesis of adipic acid from glucose still remains challenging due to the absence of biocatalysts required for the hydrogenation of unsaturated six-carbon dicarboxylic acids to adipic acid. Here, we demonstrate the first enzymatic hydrogenation of 2-hexenedioic acid and muconic acid to adipic acid using enoate reductases (ERs). ERs can hydrogenate 2-hexenedioic acid and muconic acid producing adipic acid with a high conversion rate and yield in vivo and in vitro. Purified ERs exhibit a broad substrate spectrum including aromatic and aliphatic 2-enoates and a significant oxygen tolerance. The discovery of the hydrogenation activity of ERs contributes to an understanding of the catalytic mechanism of these poorly characterized enzymes and enables the environmentally benign biosynthesis of adipic acid and other chemicals from renewable resources.
- Joo, Jeong Chan,Khusnutdinova, Anna N.,Flick, Robert,Kim, Taeho,Bornscheuer, Uwe T.,Yakunin, Alexander F.,Mahadevan, Radhakrishnan
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- Mild Carbon-Carbon Bond Cleavage of Carbonyl Compounds using Pentafluoroiodobenzene Bis(trifluoroacetate)
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Acetophenones, α-hydroxyacetophenones, deoxybenzoin, benzoin, and benzil are cleaved oxidatively with pentafluoroiodobenzene bis(-trifluoroacetate) in wet benzene at room temperature to give the corresponding benzoic acids; cyclohexanone and dimedone are cleaved to give the diacids adipic acid and 3,3-dimethylglutaric acid, respectively.
- Moriarty, Robert M.,Prakash, Indra,Penmasta, Raju
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- Simple and green oxidation of cyclohexene to adipic acid with an efficient and durable silica-functionalized ammonium tungstate catalyst
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A novel silica-functionalized ammonium tungstate interphase catalyst has been reported as a non-nitric acid route for adipic acid production from one-pot oxidative cleavage of 30% hydrogen peroxide and catalytic amounts of p-toluenesulfonic acid (PTSA). The catalyst has been simply prepared by commercially available starting material. The structure of the catalyst has been investigated using FT-IR spectroscopy, atomic absorption, TEM, SEM and XRD analysis. The catalyst has shown good to high activity even up to 10 runs of reaction. Simple preparation of the catalyst, avoids using harmful phase transfer catalyst (PTC) and/or chlorinated additives are among the other benefits of this work.
- Vafaeezadeh, Majid,Mahmoodi Hashemi, Mohammad
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- Direct oxidation of cyclohexene with inert polymeric membrane reactor
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In this work, the use of PVDF flat membranes as contactors for direct solvent-free biphasic oxidation of cyclohexene to adipic acid has been reported. The oxidation has been carried out using 30% H2O2 and ammonium molybdate ((NH4)6Mo7O 24)inthe presence of succinic acid. The effect of different membranes as interfaces between the organic phase, containing cyclo- hexene, and the aqueous phase, with the oxidant and catalyst, has been studied and related to conversion and selectivity.
- Buonomenna, Maria G.,Golemme, Giovanni,De Santo, Maria P.,Drioli, Enrico
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- Design and evaluation of improved magnetic stir bars for single-mode microwave reactors
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Magnetic stirring in sealed cylindrical vessels designed for use in single-mode microwave instruments is typically less than optimal, and is not comparable to the efficient agitation that can be generally obtained in a round-bottomed flask fitted with a suitable magnetic stir bar or using overhead mechanical stirring systems. A new "vertical blade" stir bar design that improves the stirring performance in the very narrow, flow-constricting microwave vessels has been developed and evaluated for several different transformations where stirring and efficient agitation are known to be of importance. The better performance of these novel stirrers compared to the traditional cylindrical stir bar design is not only due to the geometry of the stirrer but also to the utilization of a magnetic material with a stronger magnetic transmission force (Sm2Co17) compared to standard ferrite or AlNiCo alloys. For all three tested cases involving solid/liquid, liquid/liquid and highly viscous reaction systems, the new vertical blade stirrers showed a distinctively improved performance resulting in higher conversions and/or product yields.
- Obermayer, David,Damm, Markus,Kappe, C. Oliver
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- Adipic acid formation from cyclohexanediol using platinum and vanadium catalysts: Elucidating the role of homogeneous vanadium species
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Vanadium compounds have shown great potential alongside Pt/C for the oxidation of cyclohexanediol to adipic acid. However, the low stability of these materials often leads to ambiguity when considering the homogeneous or heterogeneous nature of the active species. In this article we describe our attempts to synthesise stable vanadium catalysts through the utilisation of vanadium bronze structures. By the addition of sodium, copper or silver into these structures, leaching could be decreased to 5% for AgVO3, compared to 88.4% with V2O5. These reactions were run in aqueous conditions under 3 bar O2. However, despite significant stabilisation of vanadium in the bronze structures, we show that as little as 7.6 ppm of a homogeneous vanadium species in the reaction solution can cause the selective oxidation of 2-hydroxycyclohexanone to adipic acid. Analysis of the speciation by 51V NMR and UV-vis has revealed the active species to be in the +5 oxidation state in the form of a decavanadate compound with the presence of small amounts of monovanadate.
- Engel, Rebecca V.,Hutchings, Graham J.,Jenkins, Robert L.,Pattisson, Samuel,Rogers, Owen,Taylor, Stuart H.,Whiston, Keith
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- Highly regioselective electrochemical synthesis of dioic acids from dienes and carbon dioxide
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A simple and efficient electrochemical method has been developed for highly regioselective synthesis of unsaturated 1,6-dioic acids from 1,3-dienes and CO2. The electrosynthesis was successfully carried out by using a nickel cathode and an aluminum anode in an undivided cell containing n-Bu 4NBr-DMF electrolyte with a constant current under 3 MPa pressure of CO2, and the sole 1,4-addition products were obtained in good to excellent yields. The plausible mechanism for electrodicarboxylation reaction of 1,3-butadiene with CO2 was discussed briefly. In addition, further research shows that 3-hexene-1,6-dioic acid could be easily converted into adipic acid via the electroreduction in the diluted H2SO4 solution.
- Li, Chuan-Hua,Yuan, Gao-Qing,Ji, Xiao-Chen,Wang, Xiu-Jun,Ye, Jian-Shan,Jiang, Huan-Feng
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- A novel 'build-bottle-around-ship' method to encapsulate metalloporphyrins in zeolite-Y. An efficient biomimetic catalyst
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Electrostatic interaction is introduced between the host and guest in the synthesis of faujasite-Y confined metallotetrakis(N,N,N-trimethylanilinium) porphyrin cations (MTMAnP4+); the synthesized composites display high catalytic activity in the oxidation of cyclohexene.
- Zhan, Bi-Zeng,Li, Xiao-Yuan
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- Natural phosphate modified by vanadium: A new catalyst for oxidation of cycloalkanones and α-ketols with oxygen molecular
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In this work, we have studied the catalytic oxidative cleavage of C-C bonds of cycloalkanones and α-ketols, in the presence of natural phosphate (NP) type fluorapatite, Ca10(PO4)6F2, and dioxygen. The aim was to find a heterogeneous system clean and efficient alternative to the industrial oxidation of cyclohexanone to adipic acid with nitric acid. The modification of the NP by vanadium leads to the preparation of a new catalyst V/PN. The latter was characterized by: XRD, FTIR, SEM and BET. It appears that vanadium is well dispersed on the surface of the NP. Using 2-methylcyclohexanone as model substrate, we optimized the conditions of reaction in order to make the system 'V/PN/O2' more performance. The comparative study between the two catalytic systems 'PN/O2' and 'V/PN/O2' shows that the latter is more active. Finally, the system 'V/PN/O2' has been recycled but low leaching of vanadium was observed in the first use of the catalyst.
- Dakkach, Mohamed,Atlamsani, Ahmed,Sebti, Sa?d
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- Intensification of cyclohexanone purification stage from impurities in caprolactam production using phase transfer catalysis
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Impurities in the oxidate, which was produced in the oxidation of cyclohexane in an industrial environment, were analyzed and identified. It is found that the amount of esters and ethers is 30% of the impurities produced, among which a cyclohexyl ethers amount is more than 50%. The process of purifying the oxidate from the impurities by hydrolysis in the presence of phase transfer catalysts and without them was studied. It has been shown that the use of trioctylmethyl ammonium chloride (Aliquat-336) in the the stage of saponification of esters enabled a removal of 90-96% of esters with reducing of reaction time in a 1.5-fold, in contrast to non-catalytic process.
- Martynenko,Glazko,Levanova,Portnova, Yu. V.
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- Influence of peroxometallic intermediaries present on polyoxometalates nanoparticles surface on the adipic acid synthesis
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The cyclohexene oxidation by hydrogen peroxide catalysed by polyoxometalates (POM) has been shown as an adequate green route for the adipic acid synthesis. In this study, it has been demonstrated that POM's salts are effective catalysts for this reaction and how peroxopolyoxometalates intermediaries are the truly responsible species of the POM's salts catalytic activity and solubility. However, the latter can be reduced by calcining the catalyst previously. Polyoxomolybdates salts generally present a higher activity than polyoxotungstenates salts. Finally, it must be remarked the positive effect exerted by the acetic acid stabilising the peroxide of hydrogen against its decomposition.
- Alca?iz-Monge,Trautwein,Garcia-Garcia
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- Dawson-type polyoxometalates as green catalysts for adipic acid synthesis
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Dawson-type POMs series of formula α- and β-K6P2W18O62 isomers, α1- and α2-K6P2Mo5W13O62 isomers, α-K6P2Mo6W12O62 isomer and α1-K7P2Mo5VW12O62 isomer, have been used as catalysts for the liquid phase oxidation of cyclohexanol, cyclohexanone and cyclohexanol/cyclohexanone mixture to form adipic acid in presence of hydrogen peroxide without solvent, without phase-transfer agents and without adding acid. 31P NMR spectroscopy of different POMs after cyclohexanol oxidation showed the formation of new active species that can be attributed to "peroxo-POMox" form. An adipic acid yield of 69% was obtained from the oxidation of a mixture of cyclohexanol (50%) and cyclohexanone (50%) with α-K6P2Mo6W12O62 isomer.
- Moudjahed,Dermeche,Benadji,Mazari,Rabia
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- A direct conversion of vic-diols into 1,2-diketones with aqueous hydrogen peroxide catalyzed by peroxotungstophosphate (PCWP)
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α-Hydroxy ketones and vic-diols were successfully oxidized to the corresponding diketones with acqueous hydrogen peroxide in the presence of a catalytic amount of peroxotungstophosphate (PCWP). This method provides a straightforward route of 1,2-diketones which are difficult to prepare by conventional oxidation of vic-diols.
- Iwahama, Takahiro,Sakaguchi, Satoshi,Nishiyama, Yutaka,Ishii, Yasutaka
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- Selective hydroxylation of cyclohexene over Fe-bipyridine complexes encapsulated into Y-type zeolite under environment-friendly conditions
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Fe-bipyridine complexes encapsulated into Na-Y ([Fe(bpy)3]2+@Y) were prepared and their catalytic activities for oxidation of cyclohexene with hydrogen peroxide in CH3CN and H2O solvents were investigated. The prepared [Fe(bpy)3]2+@Y was characterized by several methods and it was found that slightly distorted or compressed [Fe(bpy)3]2+ ions were formed within supercages of Y-type zeolite. [Fe(bpy)3]2+@Y catalyst exhibited both higher activity and higher selectivity to 2-cyclohexen-1-ol in water solvent than another Fe catalysts. In addition, the selective hydroxylation of cyclohexene to 2-cyclohexen-1-ol with molecular oxygen was successfully achieved for [Fe(bpy)3]2+@Y catalyst.
- Yamaguchi, Syuhei,Fukura, Tomohiro,Takiguchi, Keiko,Fujita, Chiharu,Nishibori, Maiko,Teraoka, Yasutake,Yahiro, Hidenori
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- Hydrophobic nature of the support: A significant effect on selective oxidation of cyclohexane with pure oxygen
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The relationship between the hydrophobic characteristic of supports and the reactivity of the liquid oxidation of cyclohexane using oxygen as oxidant was investigated. Co3O4 supported on amorphous silica was silylated with organosilane and characterized by FT-IR, contact angle testing and the retention of cyclohexane and cyclohexanone tesing on GC. Compared with unsilylated catalyst, the conversion of cycloheaxane was greatly enhanced with the silylated catalyst. And the correlation of reactivity and hydrophobicity of was observed. by Oldenbourg Wissenschaftsverlag, Mu?nchen.
- Wang, Deqiang,Zhang, Yi Bo,Li, Jing,Yang, Xiangguang
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- Oxidation of Cyclic Ketones Catalyzed by Polyethylene Glycol and Rhenium Carbonyl under Basic and Exeptionally Mild Conditions
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Monocyclic ketones react with oxygen, potassium hydroxide, potassium carbonate, and catalytic amounts of rhenium carbonyl and polyethylene glycol (PEG-400 or R4H+X- or TDA-1), at room temperature and 1 atm, to give diacids in fine yields.Bicyclic ketones afford keto diacids or hydroxyquinones, depending on the nature of the substrate.
- Osowska-Pacewicka, Krystyna,Alper, Howard
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- DOUBLE BOND CLEAVAGE REACTION OF SILYL ENOL ETHERS USING MoO2(acac)2-tBuOOH
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The double bond of various silyl enol ethers is smoothly cleaved to give carbonyl compounds by an oxidizing reagent MoO2(acac)2-tBuOOH.
- Kaneda, Kiyotomi,Kii, Nobuyoshi,Jitsukawa, Koichiro,Teranishi, Shiichiro
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- Structure and properties of tungsten peroxopolyoxo complexes - Promising catalysts for organics oxidation. I. Structure of peroxocomplexes studied during the stepwise synthesis of tetra(diperoxotungsten)phosphate-tetra-n-butyl ammonium
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Catalysis via metal complexes has been studied using EXAFS and Raman spectroscopy. Main polyoxo- and peroxopolyoxocomplexes of tungsten, resulting from the interaction of phosphorus tungsten heteropolyacid with hydrogen peroxide in water solutions, were investigated with regard to their form and structure. Interaction was shown to reduce the nuclearity of forming complexes with respect to their precursor - H3PW12O40. The symmetry of oxygen environment of tungsten was found to change, distances W-W remaining the same. After complex [Bun4N] 3{PO4[WO(O2)2]4} is isolated, binuclear anion [W2O3(O2) 4(H2O)2]2- stays in the solution. Raman scattering, EXAFS and IR spectroscopy show that isolated peroxocomplex in its crystal state has four nuclei, and most probably retains this structure being dissolved in acetonitrile. Synthesized catalytic complex [Bu n4N]3{PO4[WO(O2) 2]4} was tested in oxidation of cyclic alkenes and alcohols with hydrogen peroxide. Complex [Bun4N] 3{PO4[WO(O2)2]4} was proved to provide higher yields of mono- and dicarbonic acids in comparison to in situ synthesized catalyst.
- Pai, Zinaida P.,Kochubey, Dimitry I.,Berdnikova, Polina V.,Kanazhevskiy, Vladislav V.,Prikhod'Ko, Irina Yu.,Chesalov, Yuriy A.
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- Oxidative cleavage of cycloalkenes using hydrogen peroxide and a tungsten-based catalyst: Towards a complete mechanistic investigation
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The identification of the intermediates and by-products produced during the oxidative cleavage of cycloalkenes in the presence of H2O2 and a tungsten-based catalyst for the production of dicarboxylic acids has been carried out under various experimental conditions. On the basis of this mechanistic investigation and previous studies from the literature, a complete reaction scheme for the formation of the reaction products and by-products is proposed. In this hypothetical mechanism, the production of a hydroperoxyalcohol intermediate accounts for the two pathways proposed by Noyori and Venturello for the formation of the targeted dicarboxylic acid. In addition, Baeyer-Villiger oxidation of the mono-aldehyde intermediate allows explaining the formation of short chain diacids observed as by-products during the reaction. Hence, the proposed mechanism constitutes a real tool for scientists looking for a better understanding and those heading to set up environmentally friendly conditions for the oxidative cleavage of cycloalkenes.
- Cousin, Tony,Chatel, Gregory,Andrioletti, Bruno,Draye, Micheline
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- EVIDENCE FOR CATALYTIC ACTIVITY BY LOWER NUCLEARITY RHODIUM CARBONYLS IN THE Rh6(CO)16 CATALYZED OXIDATION OF CYCLOHEXANONE WITH MOLECULAR OXYGEN
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The yield of carboxylic acid in the Rh6(CO)16 catalyzed oxidation of cyclohexanone with molecular oxygen is higher with increasing CO pressure.The data are interpreted as providing support for a lower nuclearity rhodium carbonyl complex being involved as the reactive intermediate in the catalytic cycle.
- Dickson, Mark K.,Sudha, B. P.,Roundhill, D. Max
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- Electron-transfer Oxidation of Organic compounds. Part 5. Oxidation of cyclohexanone by the Tris-2,2'-bipyridylruthenium(III) Cation
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Evidence is presented, from kinetic and product studies, that the rate-determining step in the oxidation of cyclohexanone by the trisbipyridylruthenium(III) cation is a non-bonded electron-transfer process from the enol form of the substrate.This gives rise to a free radical and a ruthenium(II) species.The subsequent fate of the radical has been investigated.
- Audsley, Adrian J.,Quick, Geoffrey R.,Littler, John S.
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- Evidence for the presence of alternative mechanisms in the oxidation of cyclohexanone to adipic acid with oxygen, catalysed by Keggin polyoxometalates
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This report deals with the results of a study on the oxidation of cyclohexanone to adipic acid with air, catalysed by Keggin-type polyoxometalates of composition H3+xPMo12-xVxO40 (x = 1 and 2), which was carried out in a semi-continuous stirred-tank reactor. It was found that when conducted in the presence of a water-only solvent, the reaction proceeds with a redox mechanism, in which the step of reoxidation of the reduced POM by oxygen is rate limiting. When, however, the reaction was carried out with an acetic acid co-solvent, a radical-chain autoxidation mechanism prevailed, especially when very low amounts of catalyst were used. Autoxidation overlapped with the redox mechanism when the catalyst-to- cyclohexanone ratio was increased. Moreover, the composition of the polyoxometalate, that is, the number of V atoms per Keggin unit, affected the relative importance of the two mechanisms. The selectivity to adipic acid achieved was a function of the reaction mechanism, but also was affected by cyclohexanone conversion, due to the presence of a complex reaction network.
- Cavani, Fabrizio,Ferroni, Laura,Frattini, Alessandra,Lucarelli, Carlo,Mazzini, Andrea,Raabova, Katerina,Alini, Stefano,Accorinti, Pasquale,Babini, Pierpaolo
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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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- Oxidation of cyclohexanone and/or cyclohexanol catalyzed by Dawson-type polyoxometalates using hydrogen peroxide
-
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
-
-
- A decatungstate-based ionic liquid exhibiting a very low dielectric constant suitable for acting as a solvent and a catalyst for the oxidation of organic substrates
-
In this contribution, a new POM-based ionic liquid, namely (P6,6,6,14)4[W10O32], was fully characterized. Its viscosity and its very low dielectric constant make this hybrid ionic liquid suitable to be used as a solvent for organic transformations. As a proof of concept, this unique ionic liquid having both solvent and catalyst properties was tested for the catalytic oxidation of various alcohols and alkenes in the presence of H2O2.
- Martinetto, Yohan,Pégot, Bruce,Roch-Marchal, Catherine,Haouas, Mohamed,Cottyn-Boitte, Betty,Camerel, Franck,Jeftic, Jelena,Morineau, Denis,Magnier, Emmanuel,Floquet, Sébastien
-
p. 9751 - 9755
(2021/06/15)
-
- Oxidation of cyclohexanol and cyclohexanone by monochromate ions in organic solvents and on solvent free microwave irradiation under phase transfer catalysis - a comparative study
-
Oxidation of cyclohexanol and cyclohexanone were carried out by acidified monochromate ions in ethyl acetate and toluene under phase transfer catalysis and also in solvent free condition under microwave irradiation. The extraction of monochromate ions from aqueous medium to organic phase was carried by employing various phase transfer catalysts in the presence of mineral acids. The effect of [catalyst] and [mineral acid] on extraction of monochromate from aqueous phase to organic phase was also studied. The product obtained, namely adipic acid obtained with both reactants was characterized by its melting point and infrared spectral technique. The reaction was over within 15 min with more than 85% yield at a temperature of 323 K under microwave irradiation where as it gave around 70% yield at 353 K within 150 min under phase transfer catalysis condition. The enhanced reaction rate and high yield of product substantiate the application of phase transfer catalytic technique under microwave irradiation for organic synthesis. A suitable mechanism for the oxidation of substrates by monochromate under phase transfer catalysis is also suggested.
- BASHPA,RAJENDRAN,BIJUDAS
-
p. 2033 - 2037
(2021/08/24)
-
- Preparation method of adipic acid
-
Under the irradiation of visible light, the photosensitizer is used for catalyzing the cyclohexanone to synthesize adipic acid under the oxidizing environment of air, oxygen or hydrogen peroxide, the reaction condition is mild, the reaction efficiency is high, and the cost is low. In addition, the reaction can pass through the continuous flow reactor, the reactant consumption is enlarged, the reaction efficiency is improved, the reaction time is shortened, and a foundation is laid for further industrial production.
- -
-
Paragraph 0022-0044
(2021/10/27)
-
- Selective C-C Bond Cleavage of Cycloalkanones by NaNO2/HCl
-
A novel selective fragmentation of cycloalkanones by NaNO2/HCl has been established. The C-C bond cleavage reaction proceeds smoothly under mild conditions, selectively affording versatile keto acids or oxime acids. The methodology can streamline the synthesis of valuable chiral molecules and isocoumarins from readily available feedstocks.
- He, Tianyu,Chen, Dengfeng,Qian, Shencheng,Zheng, Yu,Huang, Shenlin
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supporting information
p. 6525 - 6529
(2021/09/02)
-
- Efficient oxidation of cycloalkanes with simultaneously increased conversion and selectivity using O2 catalyzed by metalloporphyrins and boosted by Zn(AcO)2: A practical strategy to inhibit the formation of aliphatic diacids
-
The direct sources of aliphatic acids in cycloalkanes oxidation were investigated, and a strategy to suppress the formation of aliphatic acids was adopted through enhancing the catalytic transformation of oxidation intermediates cycloalkyl hydroperoxides to cycloalkanols by Zn(II) and delaying the emergence of cycloalkanones. Benefitted from the delayed formation of cycloalkanones and suppressed non-selective thermal decomposition of cycloalkyl hydroperoxides, the conversion of cycloalkanes and selectivity towards cycloalkanols and cycloalkanones were increased simultaneously with satisfying tolerance to both of metalloporphyrins and substrates. For cyclohexane, the selectivity towards KA-oil was increased from 80.1% to 96.9% meanwhile the conversion was increased from 3.83 % to 6.53 %, a very competitive conversion level with higher selectivity compared with current industrial process. This protocol is not only a valuable strategy to overcome the problems of low conversion and low selectivity lying in front of current cyclohexane oxidation in industry, but also an important reference to other alkanes oxidation.
- Shen, Hai-Min,Wang, Xiong,Ning, Lei,Guo, A-Bing,Deng, Jin-Hui,She, Yuan-Bin
-
-
- Tailoring the electron density of cobalt oxide clusters to provide highly selective superoxide and peroxide species for aerobic cyclohexane oxidation
-
The catalytic aerobic cyclohexane oxidation to cyclohexanol and cyclohexanone (KA oil) is an industrially relevant reaction. This work is focused on the synthesis of tailor-made catalysts based on the well-known Co4O4 core in order to successfully deal with cyclohexane oxidation reaction. The catalytic activity and selectivity of the synthesized catalysts can be correlated with the electronic density of the cluster, modulated by changing the organic ligands. This is not trivial in cyclohexane oxidation. Furthermore, the reaction mechanism is discussed on the basis of kinetics and spin trapping experiments, confirming that the electronic density of the catalyst has a clear influence on the distribution of the reaction products. In addition, in situ Raman spectroscopy was used to characterize the oxygen species formed on the cobalt cluster during the oxidation reaction. Altogether, it can be concluded that the catalyst with the highest oxidation potential promotes the formation of peroxide and superoxide species, which is the best way to oxidize inactivated CH bonds in alkanes. Finally, based on the results of the mechanistic studies, the contribution of these cobalt oxide clusters in each single reaction step of the whole process has been proposed.
- Gaona-Miguélez, José,Gutiérrez-Tarri?o, Silvia,O?a-Burgos, Pascual
-
supporting information
p. 15370 - 15379
(2021/11/17)
-
- Novel WO3/SO42--ZrO2–TiO2 double bridge coordination catalyst hfor oxidation of cyclohexene
-
A solid super acid WO3/SO42--ZrO2–TiO2 catalyst was prepared with adjustable acidity via double bridge connection strategy for oxidation of cyclohexene (CHE) to adipic acid (AA). XRD, SEM and N2 adsorption-desorption isotherm indicated that WO3 was successfully decorated and was highly dispersed on SO42--ZrO2–TiO2 surface. An obvious stretching vibration peak (1125-1055 ?cm?1) in FT-IR illustrated that connection effect between SO42? and ZrO2–TiO2 was double bridge connection. NH3-TPD profile appeared a strong acid center peak (516 ?°C), while this center of solid super acid catalyst could reduce decomposition rate of H2O2 directly, and increase reaction time between CHE and H2O2 meanwhile. The marked catalytic performance was attributed to the synergistic effect between WO3 and SO42--ZrO2–TiO2. DFT calculation was employed to further analyze reaction process and system energy.
- Liu, Xiangxue,Wang, Ke,Liu, Baoquan,Guo, Zhenmei,Zhang, Chao,Lv, Zhiguo
-
-
- 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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- Identification of key oxidative intermediates and the function of chromium dopants in PKU-8: catalytic dehydrogenation ofsec-alcohols withtert-butylhydroperoxide
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Catalytic oxidation reaction using green oxidants plays an important role in modern chemical engineering; however, thein situgenerated active species and the related catalytic mechanism need to be understood in depth. For this purpose, Cr-substituted aluminoborate Cr-PKU-8 catalysts were synthesized and applied as recyclable heterogeneous catalysts for the oxidation of aliphatic and aromatic alcohols usingtert-butylhydroperoxide (TBHP). Both high efficiency and selectivity (>99%) were achieved during the dehydrogenation of varioussec-alcohols into acetone in H2O solvent medium. From the analyses using isotopic tracer, molecular probe and cyclic voltammetry strategies, the chromium ions were observed to undergo a Cr3+-Cr2+-Cr3+redox cycle. DFT calculations suggest thatt-BuOO* is more energetically favourable for hydrogen abstraction fromsec-alcohol thant-BuO*, and probably acts as the key active species. Accordingly, the reaction scheme was proposed to interpret the catalytic process based on the observed results.
- Wang, Weilu,He, Yang,He, Junkai,Dang, Yanliu,Kankanmkapuge, Tharindu,Gao, Wenliang,Cong, Rihong,Suib, Steven L.,Yang, Tao
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p. 1365 - 1374
(2021/03/14)
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- Microwave-Assisted Nickel-Catalyzed Rapid Reductive Coupling of Ethyl 3-iodopropionate to Adipic Acid
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Abstract: 3-iodopropionic acid (3-IPA) can be efficiently synthesized from the glycerol derivative glyceric acid (GA), which is a potential biomaterial-based platform molecule. In this report, ethyl 3-iodopropionate was rapidly dimerized to diethyl adipate in a microwave reactor using NiCl2·6H2O as a catalyst, co-catalyzed by Mn and the 1, 10-Phenanthroline monohydrate ligand. Under the optimum reaction conditions, diethyl adipate can be obtained with 84% yield at 90?°C in just 5?min. Diethyl adipate was hydrolyzed to obtain the adipic acid (AA) in 89% yield with an acid catalyst. AA is an important chemical and a monomer for producing a wide range of high-performance polymeric substances. This rapid coupling method is also applicable to other alkyl halides. Graphic Abstract: [Figure not available: see fulltext.]
- Zhang, Linfeng,Zheng, Jing,Zou, Wenya,Shu, Yongqi,Yang, Weiran
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p. 2339 - 2345
(2021/01/04)
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- Visible Light-Driven, Copper-Catalyzed Aerobic Oxidative Cleavage of Cycloalkanones
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A visible light-driven, copper-catalyzed aerobic oxidative cleavage of cycloalkanones has been presented. A variety of cycloalkanones with varying ring sizes and various α-substituents reacted well to give the distal keto acids or dicarboxylic acids with moderate to good yields.
- Xin, Hong,Duan, Xin-Hua,Yang, Mingyu,Zhang, Yiwen,Guo, Li-Na
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p. 8263 - 8273
(2021/06/30)
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- Method for co-producing adipic acid and cyclohexanone-oxime from cyclohexane
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The invention relates to a method for co-producing adipic acid and cyclohexanone-oxime from cyclohexane. The method comprises the following steps: (1) carrying out oxidation nitration on cyclohexane and NOx to generate adipic acid, nitrocyclohexane, nitrogen oxides and a byproduct-A, and separating to obtain crude adipic acid and nitrocyclohexane; (2) carrying out catalytic hydrogenation on the obtained nitrocyclohexane and hydrogen to generate cyclohexanone-oxime and a small amount of cyclohexylamine, separating to obtain crude cyclohexanone-oxime and cyclohexylamine, and enabling cyclohexylamine to be directly used as a byproduct or to be continuously converted into cyclohexanone-oxime. and (3) partially oxidizing the cyclohexylamine obtained in the previous step with molecular oxygen to obtain an oxidation reaction product consisting of cyclohexanone-oxime, a byproduct B and possibly unconverted cyclohexylamine, and then separating the oxidation reaction product without separation, or firstly separating part or all of water in the oxidation reaction product, carrying out hydrogenation amination reaction under the action of a catalyst, or carrying out hydrogenation and amination reaction, or only carrying out hydrogenation reaction, and then separating to obtain the cyclohexanone-oxime. The method can realize high-selectivity co-production of adipic acid and cyclohexanone-oxime, and is short in process flow, low in equipment investment and low in material consumption, energy consumption and cost.
- -
-
Paragraph 0100-0107
(2021/06/13)
-
- METHOD FOR PRODUCING DICARBOXYLIC ACID
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A method for producing dicarboxylic acid. The method includes: subjecting a raw material system including a cyclic olefin and a lower monocarboxylic acid to an addition reaction in the presence of an addition reaction catalyst to generate an intermediate product system including cyclic carboxylic acid ester; and subjecting the intermediate product system including cyclic carboxylic acid ester to a ring-opening and oxidation reaction in the presence of an oxidant and an oxidation catalyst to generate a corresponding dicarboxylic acid product. The addition reaction in the dicarboxylic acid synthesis route achieves a high single-pass conversion rate, and the selectivity of the corresponding cyclic carboxylic acid ester is high. The addition-oxidation synthesis route achieves faster reaction rates for both the addition reaction and oxidation reaction, and high yield of corresponding dicarboxylic acid product. The addition-oxidation based synthesis route is suitable for continuous, stable and large-scale production of corresponding dicarboxylic acid product.
- -
-
Paragraph 0117
(2021/05/21)
-
- METAL-FREE METHOD FOR OXIDATIVE CLEAVAGE OF VIC-DIOLS TO CARBOXYLIC ACIDS
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The invention relates to a simple and efficient metal-free method for oxidative cleavage of vic-diols, in particular those derived from fatty esters, to the corresponding carboxylic acids, using a cheap, safe and environmentally friendly oxidant under mild conditions wherein oxone? is used as an oxidant and a halide as a catalyst in presence of the accurate organic solvent.
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Page/Page column 8; 9
(2021/11/13)
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- Synthetic method of adipic acid
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The invention discloses a synthetic method of adipic acid, and belongs to the technical field of organic synthesis. The method comprises the following steps: 1) dissolving a catalyst in a nitric acidsolution to prepare oxidized acid; 2) reacting the oxidized acid with KA oil at a certain temperature; and 3) after the reaction time is up, cooling, crystallizing, carrying out suction filtration, and drying to obtain the product adipic acid. The method has the advantages of low catalyst consumption, high product selectivity and high yield.
- -
-
Paragraph 0016-0033
(2021/02/24)
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- A Zr-Based Metal-Organic Framework with a DUT-52 Structure Containing a Trifluoroacetamido-Functionalized Linker for Aqueous Phase Fluorescence Sensing of the Cyanide Ion and Aerobic Oxidation of Cyclohexane
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A zirconium (Zr) metal-organic framework having a DUT-52 (DUT stands for Dresden University of Technology) structure with face-centered cubic topology and bearing the rigid 1-(2,2,2-trifluoroacetamido) naphthalene-3,7-dicarboxylic acid (H2NDC-NHCOCF3) ligand was prepared, and its solid structure was characterized with the help of the X-ray powder diffraction (XRPD) technique. Other characterization methods like thermogravimetric analysis (TGA) and Fourier transform infrared (FT-IR) spectroscopy were applied to verify the phase purity of the compound. In order to get the solvent-free compound (1′), 1 was stirred with methanol for overnight and subsequently heated at 100 °C overnight under vacuum. As-synthesized (1) and activated (1′) compounds are thermally stable up to 300 °C. The Brunsuer Emmett-Teller (BET) surface area of 1′ was found to be 1105 m2 g-1. Fluorescence titration experiments showed that 1′ exhibits highly selective and sensitive fluorescence turn-on behavior toward cyanide (CN-) anion. The interference experiments suggested that other anions did not interfere in the detection of CN-. Moreover, a very short response time (2 min) was shown by probe 1′ for CN- detection. The detection limit was found to be 0.23 μM. 1′ can also be effectively used for CN- detection in real water samples. The mechanism for the selective detection of CN- was investigated systematically. Furthermore, the aerobic oxidation of cyclohexane was performed with 1′ under mild reaction conditions, observing higher activity than the analogous DUT-52 solid under identical conditions. These experiments clearly indicate the benefits of hydrophobic cavities of 1′ in achieving higher conversion of cyclohexane and cyclohexanol/cyclohexanone selectivity. Catalyst stability was proved by two consecutive reuses and comparing the structural integrity of 1′ before and after reuses by the XRPD study.
- Gogoi, Chiranjib,Nagarjun, Nagarathinam,Roy, Shubasis,Mostakim,Volkmer, Dirk,Dhakshinamoorthy, Amarajothi,Biswas, Shyam
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supporting information
p. 4539 - 4550
(2021/04/06)
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- Scalable, sustainable and catalyst-free continuous flow ozonolysis of fatty acids
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A simple and efficient catalyst-free protocol for continuous flow synthesis of azelaic acid is developed from the renewable feedstock oleic acid. An ozone and oxygen mixture was used as the reagent for oxidative cleavage of double bond without using any metal catalyst or terminal oxidant. The target product was scaled up to more than 100 g with 86% yield in a white powder form. Complete recycling and reuse of the solvent were established making it a green method. The approach is significantly energy efficient and also has a very small chemical footprint. The methodology has been successfully tested with four fatty acids making it a versatile platform that gives value addition from renewable resources.
- Atapalkar, Ranjit S.,Athawale, Paresh R.,Srinivasa Reddy,Kulkarni, Amol A.
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supporting information
p. 2391 - 2396
(2021/04/07)
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- Electrochemical hydrogenation of bioprivileged: Cis, cis -muconic acid to trans -3-hexenedioic acid: From lab synthesis to bench-scale production and beyond
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The integration of microbial and electrochemical conversions in hybrid processes broadens the portfolio of products accessible from biomass. For instance, sugars and lignin monomers can be biologically converted to cis,cis-muconic acid (ccMA), a bioprivileged intermediate, and further electrochemically upgraded to trans-3-hexenedioic acid (t3HDA). This novel monounsaturated monomer is gaining increasing attention as it can substitute adipic acid in Nylon 6,6 to introduce desired properties and yield polyamides with performance advantages. The implementation of t3HDA for advanced polymer production is, however, hampered by the low productivities achieved to date, in the order of milligrams per hour per cm2. Here, we report on new synergies between microbial and electrochemical conversions and present a simple strategy to enhance the productivity of t3HDA by over 50 times. Specifically, we show that the broth composition has a dramatic role on the subsequent electrochemical step. Broth with neutral pH and high ccMA titer obtained from bacteria was found to enhance the electrochemical hydrogenation while impeding the parasitic hydrogen evolution reaction. As a result, high productivities were achieved under industrially-relevant current densities (200-400 mA cm-2). The effect of other parameters that are key for scale up and continuous operation, namely reactor configuration, potentiostatic/galvanostatic operation mode, and cathode material are also discussed. The experimental results served as input parameters for a detailed technoeconomic analysis and the blueprint of a hybrid microbial electrosynthesis process for t3HDA production.
- Bateni, Hamed,Dell'Anna, Marco Nazareno,Laureano, Mathew,Matthiesen, John E.,Paskach, Thomas J.,Tessonnier, Jean-Philippe,Zaza, Ludovic,Zembrzuski, Michael P.
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p. 6456 - 6468
(2021/09/10)
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- PROCESS FOR PRODUCING DIALDEHYDE
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PROBLEM TO BE SOLVED: To provide a process for producing dialdehyde in high yield. SOLUTION: Provided is a process for producing a dialdehyde, comprising the step of reacting a cyclic alkene with an oxidizing agent in the presence of a catalyst having mononuclear ruthenium immobilized on a catalyst carrier. SELECTED DRAWING: None COPYRIGHT: (C)2020,JPOandINPIT
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-
Paragraph 0025-0026; 0028-0029
(2020/05/16)
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- A biradical oxo-molybdenum complex containing semiquinone and: o -aminophenol benzoxazole-based ligands
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We report a new mononuclear molybdenum(iv) complex, MoOLBISLSQ, in which LSQ (2,4-di-tert-butyl o-semibenzoquinone ligand) has been prepared from the reaction of the o-iminosemibenzoquinone form of a tridentate non-innocent benzoxazole ligand, LBIS, and MoO2(acac)2. The complex was characterized by X-ray crystallography, elemental analysis, IR and UV-vis spectroscopy and magnetic susceptibility measurements. The crystal structure of MoOLBISLSQ revealed a distorted octahedral geometry around the metal centre, surrounded by one O and two N atoms of LBIS and two O atoms of LSQ. The effective magnetic moment (μeff) of MoOLBISLSQ decreased from 2.36 to 0.2 μB in the temperature range of 290 to 2 K, indicating a singlet ground state caused by antiferromagnetic coupling between the metal and ligand centred unpaired electrons. Also, the latter led to the EPR silence of the complex. Cyclic voltammetry (CV) studies indicate both ligand and metal-centered redox processes. MoOLBISLSQ was applied as a catalyst for the oxidative cleavage of cyclohexene to adipic acid and selective oxidation of sulfides to sulfones with aqueous hydrogen peroxide. This journal is
- Galindo, Agustín,Jagli?i?, Zvonko,Masoumpour, Marzieh Sadat,Nasibipour, Mina,Safaei, Elham,Wojtczak, Andrzej
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p. 40853 - 40866
(2020/11/23)
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- A Janus-type Heterogeneous Surfactant for Adipic Acid Synthesis
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A highly water-dispersible heterogeneous Br?nsted acid surfactant was prepared by synthesis of a bi-functional anisotropic Janus-type material. The catalyst comprises ionic functionalities on one side and propyl-SO3H groups on the other. The novel material was investigated as a green substitute of a homogeneous acidic phase transfer catalyst (PTC). The activity of the catalyst was investigated for the aqueous-phase oxidation of cyclohexene to adipic acid with 30 % hydrogen peroxide even in a decagram-scale. It can also be used for the synthesis of some other carboxylic acid derivatives as well as diethyl phthalate.
- Antonyuk, Sergiy,Breuninger, Paul,Ernst, Stefan,Thiel, Werner R.,Vafaeezadeh, Majid,Wilhelm, Christian
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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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- Method for catalytic oxidation of cycloalkane by confinement porphyrin Co (II)
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The invention relates to a method for catalytic oxidation of cycloalkane by confinement porphyrin Co (II). The method comprises the following steps: dispersing confinement cobalt porphyrin (II) in cycloalkane, sealing the reaction system, heating to 100-130 DEG C while stirring, introducing oxygen to 0.2-3.0 MPa, keeping the set temperature and oxygen pressure, stirring to react for 3.0-24.0 h, and carrying out post-treatment on a reaction solution to obtain products naphthenic alcohol and naphthenic ketone. The method achieves high selectivity of naphthenic alcohol and naphthenic ketone, andeffectively inhibits the generation of aliphatic diacid. The aliphatic diacid is low in selectivity, so that the continuity of the cycloalkane oxidation process and the separation of the products arefacilitated; the method has the potential of solving the problem that naphthenic alcohol and naphthenic ketone are easily and deeply oxidized to generate aliphatic diacid in the industrial cycloalkanecatalytic oxidation process; and the method is a novel efficient and feasible method for selective catalytic oxidation of cycloalkane.
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Page/Page column 8-10
(2020/05/01)
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- Confinement porphyrin Co (II), and preparation method and application thereof
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Confinement porphyrin Co (II). A preparation method includes: under acidic condition, performing condensation on aromatic aldehyde and pyrrole in equal molar ratio to obtain a phenylporphyrin compound, and carrying out metallization in a chloroform-methanol solution to obtain porphyrin Cu (II), performing bromination and demetalization by perchloric acid to obtain confinement porphyrin, performingstirring reflux on the confinement porphyrin in a methanol solution for 12.0-24.0 h to obtain confinement porphyrin Co (II). An application includes: dissolving the confinement porphyrin Co (II) in naphthenic hydrocarbon and sealing the reaction system, stirring and heating the reaction system to 100-130 DEG C and feeding oxygen to 0.2-3.0 MPa; maintaining the set temperature and oxygen pressureand performing a stirring reaction for 3.0-24.0 h; performing after treatment on the reaction liquid to prepare the product. In the invention, generation of fatty diacid is effectively inhibited, andcontinuity of a naphthenic hydrocarbon oxidization process and product separation is facilitated. The invention has the potential of solving the problem that naphthene alcohols and naphthene ketones are liable to undergo deep oxidization and form the fatty diacid in an industrial naphthenic hydrocarbon catalytic oxidation process.
- -
-
Paragraph 0061-0098; 0107-0108
(2020/04/17)
-
- Method for synergistically catalyzing and oxidizing cycloparaffin through confined metalloporphyrin cobalt (II)/Cu (II) salt
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The invention discloses a method for synergistically catalyzing and oxidizing cycloparaffin through confined metalloporphyrin cobalt (II)/Cu (II) salt. The preparation method comprises the following steps: dispersing confined metalloporphyrin cobalt (II) (0.001%-5%, g/mol) and Cu (II) salt (0.01%-10%, mol/mol) into cycloparaffin; and sealing the reaction system, heating the temperature to 90-150 DEG C while stirring, introducing an oxidant, keeping the set temperature and pressure, carrying out stirring and reacting for 2.0-24.0 hours, and carrying out after-treatment on the reaction solutionto obtain the products cycloalkyl alcohol and cycloalkyl ketone. The method disclosed by the invention has the advantages of high cycloalkyl alcohol and cycloalkyl ketone selectivity, low reaction temperature, few byproducts, small environmental influence and the like. In addition, the content of cycloalkyl hydroperoxide is low, and the safety coefficient is high. The invention provides an efficient, feasible and safe method for synthesizing cycloalkyl alcohol and cycloalkyl ketone through selective catalytic oxidation of cycloparaffin.
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-
Paragraph 0057-0058; 0063-0064; 0071-0074; 0089-0108
(2020/12/10)
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- Synthesis of Dicarboxylic Acids from Aqueous Solutions of Diols with Hydrogen Evolution Catalyzed by an Iridium Complex
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A catalytic system for the synthesis of dicarboxylic acids from aqueous solutions of diols accompanied by the evolution of hydrogen was developed. An iridium complex bearing a functional bipyridonate ligand with N,N-dimethylamino substituents exhibited a high catalytic performance for this type of dehydrogenative reaction. For example, adipic acid was synthesized from an aqueous solution of 1,6-hexanediol in 97 % yield accompanied by the evolution of four equivalents of hydrogen by the present catalytic system. It should be noted that the simultaneous production of industrially important dicarboxylic acids and hydrogen, which is useful as an energy carrier, was achieved. In addition, the selective dehydrogenative oxidation of vicinal diols to give α-hydroxycarboxylic acids was also accomplished.
- Fujita, Ken-ichi,Toyooka, Genki
-
-
- A sustainable synthetic route for biobased 6-hydroxyhexanoic acid, adipic acid and ?-caprolactone by integrating bio- And chemical catalysis
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A green route for the production of 6-carbon polymer building blocks 6-hydroxyhexanoic acid, adipic acid and ?-caprolactone from 1,6-hexanediol, a hydrogenation product of biobased 5-hydroxymethylfurfural is reported. Gluconobacter oxydans oxidized 1,6-hexanediol completely to adipic acid, and selectively at pH 6-7 to 6-hydroxyhexanoic acid, which was converted to ?-caprolactone by catalytic cyclization. This journal is
- Hatti-Kaul, Rajni,Park, Ji Hoon,Pyo, Sang-Hyun,Srebny, Vanessa
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supporting information
p. 4450 - 4455
(2020/08/10)
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- Cobalt-Catalyzed Acceptorless Dehydrogenation of Alcohols to Carboxylate Salts and Hydrogen
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The facile oxidation of alcohols to carboxylate salts and H2 is achieved using a simple and readily accessible cobalt pincer catalyst (NNNHtBuCoBr2). The reaction follows an acceptorless dehydrogenation pathway and displays good functional group tolerance. The amine-amide metal-ligand cooperation in cobalt catalyst is suggested to facilitate this transformation. The mechanistic studies indicate that in-situ-formed aldehydes react with a base through a Cannizzaro-type pathway, resulting in potassium hemiacetolate, which further undergoes catalytic dehydrogenation to provide the carboxylate salts and H2
- Gunanathan, Chidambaram,Kishore, Jugal,Pattanaik, Sandip,Pradhan, Deepak Ranjan
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supporting information
(2020/03/03)
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- Non-metallic Aerobic Oxidation of Alcohols over Anthraquinone Based Compounds
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The catalytic performances of substituted anthraquinones were investigated in catalytic oxidation of alcohols like cyclohexanol, benzyl alcohol and 5-hydroxymethylfurfural (HMF) to carbonyl compounds (cyclohexanone, benzyl aldehyde and diformylfuran). The reduction potential of anthraquinone plays the key role in the oxidation reactions. TOF numbers and selectivities to carbonyl compounds pass through the maximum with increase of the reduction potential. The maximum activity and selectivity (>80 %) is observed for sulfonated and carboxylated anthraquinones having intermediate reduction potentials (≈ 0.1-0.2 V vs SHE). Grafted 2-carboxyanthraquinone catalyst has demonstrated comparable catalytic performance to the parent molecule and might be used as heterogeneous catalyst. The oxidation reaction was found to have radical character with transfer of hydrogen from alcohol to anthraquinone and subsequent oxidation of hydrogenated anthraquinone by oxygen.
- Zhao, Jingpeng,Wu, Dan,Hernández, Willinton Yesid,Zhou, Wen-Juan,Capron, Mickael,Ordomsky, Vitaly V.
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- Method for preparing adipic acid by cyclohexane oxidation
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The invention relates to a method for preparing adipic acid by cyclohexane oxidation, which mainly solves the problems that in the prior art, in the reaction of preparing adipic acid through cyclohexane oxidation, various metal catalysts need to be adopted, the metal catalysts enter soil and water along with waste residues and waste liquid, and serious environmental pollution is caused. The methodfor preparing adipic acid by cyclohexane oxidation comprises the following steps of in the presence of a reaction promoter and a solvent, reacting cyclohexane with an oxidant containing oxygen molecules to obtain adipic acid, wherein the reaction promoter comprises an organic azo compound, or the reaction promoter comprises quinone. The problems are better solved, and the method can be used for industrial production of adipic acid through air oxidation of cyclohexane.
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Paragraph 0071-0105
(2021/01/04)
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- Process for preparing adipic acid by catalytic oxidation of cyclohexane and preparation method of acid-modified sepiolite catalyst
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The oxidation catalyst, for preparing adipic acid by one-step oxidation of cyclohexane mainly solves the problems that in the prior art, the catalyst yield is low, selectivity difference and the oxidation process avoids the pollution. of nitric acid to the environment through the different inorganic or organic acid acid modification treatment, through different inorganic or organic acid acid modification treatments to obtain, catalyst active phase structure ratio adjustable by acid treatment mode . The preparation method is simple. The method can be used for preparing adipic acid by using cheap sepiolite raw ore, through different inorganic or organic acid acid modification treatment methods 62.3%; with different inorganic or organic acid acid modification treatment methods in an acid treatment manner to dry. the environment .
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Paragraph 0008-0015
(2020/03/17)
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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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- Morphology-Reserved Synthesis of Discrete Nanosheets of CuO?SAPO-34 and Pore Mouth Catalysis for One-Pot Oxidation of Cyclohexane
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Discrete nanosheets of silicon-doped AlPO4 molecular sieves (SAPO-34) with a thickness of ≈7 nm have been prepared through morphology-reserved synthesis with a lamellar aluminum phosphate as precursor. Cages of the nanosheets are in situ incorporated with copper oxide clusters. The CuO?SAPO-34 nanosheets exhibit a large external surface area with a high number of (010) channel pores on the surface. Due to the thin morphology, copper oxide clusters occupy the outmost cages with a probability >50 %. The distinctive configuration facilitates a new concept of pore mouth catalysis, i.e., reactant molecules larger than the pores cannot enter the interior of the molecular sieves but can interact with the CuO clusters at “the mouth” of the pore. In heterogeneous catalysis, CuO?SAPO-34 nanosheets have shown top performance in one-pot oxidation of cyclohexane to adipic acid by O2, a key compound for the manufacture of nylon-66, which is so far produced using non-green nitric acid oxidation.
- Chen, Zhaoxu,Ding, Weiping,Guo, Xiangke,Guo, Xuefeng,Lin, Ming,Peng, Luming,She, Minyi,Shi, Taotao,Xu, Mengxia,Zhu, Yan
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supporting information
p. 2606 - 2611
(2020/01/24)
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- Aerobic oxidation of 1,6-hexanediol to adipic acid over Au-based catalysts: The role of basic supports
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1,6-Hexanediol is one of the most relevant building blocks originating from biomass and it transforms into adipic acid for polymer synthesis. Herein, we examine the selective oxidation of 1,6-hexanediol to adipic acid over Au-based catalysts, in the aqueous phase, under base-free conditions. Particularly, the absence of a base allows the neutralization step at the end of the reaction to be avoided. The influences of various supports (MgO, BaO, NiO, and TiO2) and substrate/gold molar ratios were studied. Under the conditions used, the leaching of Mg in the mixture of MgF2 and MgO was limited by diluting the basic sites in the support. The highest selectivity to adipic acid (43%) was achieved at 110 °C under 15 bar of air in the presence of 2 wt% Au/0.6MgF2-0.4MgO.
- Capece, Noemi,Cavani, Fabrizio,Palombo Ferraz, Camila,Paul, Sébastien,Pietrowski, Mariusz,Sadier, Achraf,Thuriot-Roukos, Jo?lle,Wojcieszak, Robert,Zieliński, Micha?
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p. 2644 - 2651
(2020/05/14)
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- METHOD OF PREPARING ADIPIC ACID
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Disclosed is a method of preparing adipic acid from d-glucaro-1,4:6,3-dilactone, particularly using a rhenium catalyst and a noble metal catalyst. Further the method may include using an environmentally friendly solvent such as water. Thus, the obtained adipic acid may have high purity as a final product and economic efficiency of the preparation process may be improved.
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Paragraph 0089; 0090
(2020/03/23)
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- METHOD FOR PRODUCING ADIPAMIDE AS INTERMEDIATE FOR PRODUCTION OF RAW MATERIAL FOR BIO-BASED NYLON
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Disclosed is a method for producing adipamide, which may include the steps of: (a) reacting glucose, nitric acid (HNO3), sodium nitrite (NaNO2) and potassium hydroxide (KOH) to produce a glucaric acidpotassium salt, (b) producing glucamide by reacting the glutaric acid potassium salt, with an acidic solution and removing a potassium ion from the glucaric acid potassium salt, (c) preparing an reaction admixture by adding the glucamide and a catalyst to hydrogen halide and acetic acid, and (d) treating the reaction admixture with hydrogen gas in a reactor thereby producing the adipamide.
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Paragraph 0098-0100
(2020/03/17)
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- Direct and Selective Synthesis of Adipic and Other Dicarboxylic Acids by Palladium-Catalyzed Carbonylation of Allylic Alcohols
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A general and direct synthesis of dicarboxylic acids including industrially important adipic acid by palladium-catalyzed dicarbonylation of allylic alcohol is reported. Specifically, the combination of PdCl2 and a bisphosphine ligand (HeMaRaphos) promotes two different carbonylation reactions with high activity and excellent selectivity.
- Beller, Matthias,Ge, Yao,Huang, Weiheng,Jackstell, Ralf,Liu, Jiawang,Neumann, Helfried,Yang, Ji
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supporting information
p. 20394 - 20398
(2020/09/21)
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- Catalytic Oxidative Deamination by Water with H2Liberation
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Selective oxidative deamination has long been considered to be an important but challenging transformation, although it is a common critical process in the metabolism of bioactive amino compounds. Most of the synthetic methods developed so far rely on the use of stoichiometric amounts of strong and toxic oxidants. Here we present a green and efficient method for oxidative deamination, using water as the oxidant, catalyzed by a ruthenium pincer complex. This unprecedented reaction protocol liberates hydrogen gas and avoids the use of sacrificial oxidants. A wide variety of primary amines are selectively transformed to carboxylates or ketones in good to high yields. It is noteworthy that mechanistic experiments and DFT calculations indicate that in addition to serving as the oxidant, water also plays an important role in assisting the hydrogen liberation steps involved in amine dehydrogenation.
- Tang, Shan,Rauch, Michael,Montag, Michael,Diskin-Posner, Yael,Ben-David, Yehoshoa,Milstein, David
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supporting information
p. 20875 - 20882
(2020/12/23)
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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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- Organic salts and merrifield resin supported [PM12O40]3? (M = Mo or W) as catalysts for adipic acid synthesis
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Adipic acid (AA) was obtained by catalyzed oxidation of cyclohexene, epoxycyclohexane, or cyclohexanediol under organic solvent-free conditions using aqueous hydrogen peroxide (30%) as an oxidizing agent and molybdenum- or tungsten-based Keggin polyoxometalates (POMs) surrounded by organic cations or ionically supported on functionalized Merrifield resins. Operating under these environmentally friendly, greener conditions and with low catalyst loading (0.025% for the molecular salts and 0.001–0.007% for the supported POMs), AA could be produced in interesting yields.
- Pisk, Jana,Agustin, Dominique,Poli, Rinaldo
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- Method for preparing 1,6-adipaldehyde through selective oxidation of cyclohexene
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The invention discloses a method for preparing 1,6-adipaldehyde through selective oxidation of cyclohexene. A catalyst is a cobalt complex of an isosteviol derivative. The method comprises the steps as follows: adding a solvent, cyclohexene, a catalyst and a cocatalyst to a reaction kettle, introducing oxygen, keeping the pressure of the reaction kettle at 0.2-0.6 MPa, and conducting a reaction atthe temperature of 120-170 DEG C for 60-300 min to obtain 1,6-adipaldehyde. Compared with existing methods, the method has the advantages that free radicals produced through decomposition of the cocatalyst tert-butyl hydroperoxide act with oxygen to produce oxygen radicals, the catalyst cobalt complex of the isosteviol derivative acts with double bonds in cyclohexene, so that the reaction activity is higher, and activated double bonds and free radicals react to produce 1,6-adipaldehyde. The method is environmentally friendly, and 1,6-adipaldehyde is good in selectivity and high in yield.
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Paragraph 0022; 0025; 0032; 0039; 0047; 0052; 0055
(2019/03/08)
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- Green Oxidation of Cyclohexanone to Adipic Acid over Phosphotungstic Acid Encapsulated in UiO-66
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Abstract: A very stable catalyst, phosphotungstic acid (PTA) encapsulated in metal–organic framework UiO-66, was prepared by a simple one-pot solvothermal method. Characterization results show that UiO-66 is quite stable in the catalyst preparation process, and PTA is encapsulated in the cavities of UiO-66 with good dispersity. The as-synthesized composite material exhibited good catalytic activity and excellent reusability for the green oxidation of cyclohexanone to adipic acid (AA). Under mild reaction conditions, the isolated yield of AA was as high as 80.3% without the introduction of any organic solvent or phase transfer agent. The excellent immobilization effect of UiO-66 for PTA is mainly because UiO-66 has a well matched window size to confine PTA molecule in its nanocages. Graphical Abstract: [Figure not available: see fulltext.].
- Feng, Jian,Li, Min,Meng, Xiaojing
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- Preparation and characterization of H3?2(x+y)MnxCoyPMo12O40 heteropolysalts. Application to adipic acid green synthesis from cyclohexanone oxidation with hydrogen peroxide
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H3?2(x+y)MnxCoyPMo12O40 heteropolysalts (x + y ≤ 3/2 and x, y: 0–1.5) were prepared by a cationic exchange method based on barium sulfate precipitation. Structural and textural properties of salts were examined by several physicochemical techniques such as infrared, scanning electron microscopy-energy dispersive X-ray, and 31P nuclear magnetic resonance spectroscopies, X-ray diffraction diffraction, and thermogravimetric analysis, and their catalytic properties were evaluated in the cyclohexanone oxidation using hydrogen peroxide (30%). The reaction products, adipic, glutaric, succinic, hexanoic, 6-hydroxyhexanoic, 7,7-dimethoxy, and heptanoic acids and 1,1-dimethoxy octane were identified by gas chromatography–mass spectrometry analysis. Only adipic, glutaric, and succinic acids were quantified by chromatography (high-performance liquid chromatography), the other products were noted X. Adipic acid (AA) is the major product for all systems. The effects of molar ratios of catalyst/reactant and cyclohexanol/cyclohexanone, heteropolysalt composition, and reaction duration on AA yield were investigated. The stability of the catalytic system was also examined. H3?2(x+y)MnxCoyPMo12O40 catalysts were found to be efficient for the cyclohexanone oxidation with conversions >95%. Among them, H1Mn0.25Co0.75 exhibits the highest AA yield (75%).
- Mouanni, Sihem,Mazari, Tassadit,Amitouche, Dahbia,Benadji, Sihem,Dermeche, Leila,Roch-Marchal, Catherine,Rabia, Chérifa
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p. 327 - 336
(2019/02/25)
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- Synergistic hydrogen atom transfer with the active role of solvent: Preferred one-step aerobic oxidation of cyclohexane to adipic acid by N-hydroxyphthalimide
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In this work, we developed an one-step aerobic oxidation of cyclohexane to prepare adipic acid, catalyzed by N-hydroxyphthalimide (NHPI) under promoter- and metal-free conditions. A significant beneficial solvent effect for synergistic reaction is observed with varying polarity and hydrogen-bonding strength: detailed study reveals that the solvent environments manipulate catalytic activity and adipic acid selectivity. Cyclic voltammetry measurements and UV–visible spectra of the NHPI catalyst are examined in various solvent environments to understand the active role of solvent in influencing the catalytic-site structure (>NOH) of the molecule. Analysis of the UV–visible spectra reveals that these differences can be rationalized by considering hydrogen-bonding with solvent molecules, which modifies the catalytic-site structure. This observation is in agreement with cyclic voltammetry results: the different reversibility of the catalytic-site (>NOH/>NO[rad]) wave shows that the catalytic activity of NHPI is related to the formation of hydrogen bonds with the active participation of solvents. Computational studies presented herein have furnished mechanistic insights into the effect of solvent environments. Specifically, we present the structures, dissociation energies, and reaction barriers from DFT studies of the reactants and reaction intermediates involved in the two types of H-abstraction on >NO[rad] catalytic-sites for the rate-determining step. The results of modeling the solvent effects using the PCM continuum solvent method predict that the resulting reaction barrier of the rate-controlling H-abstraction for cyclohexane and cyclohexanone is modified significantly: the transition state barrier of H-abstraction for cyclohexane decreases from 22.36 (in benzene) to 20.78 kcal?mol?1 (in acetonitrile); the α-H-abstraction barrier for cyclohexanone decreases from 21.45 to 20.53 kcal?mol?1. The active participation of solvent molecule results in a strong interaction between pre-reaction complex (PINO???H???C NO[rad] catalytic-sites at the transition state. The lower calculated barriers of H-abstraction for cyclohexanone oxidation approximate more closely the experimental results of the higher adipic acid selectivity. Our work provides a dimension of sustainable chemistry for the metal-free preparation of adipic acid: a conversion of 27% with 79% adipic acid selectivity is achieved over use of NHPI catalysts in CH3CN solvent.
- Liang, Futong,Zhong, Wenzhou,Xiang, Liping,Mao, Liqiu,Xu, Qiong,Kirk, Steven Robert,Yin, Dulin
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p. 256 - 269
(2019/09/30)
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