- Visible photorelease of liquid biopsy markers following microfluidic affinity-enrichment
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We detail a heterobifunctional, 7-aminocoumarin photocleavable (PC) linker with unique properties to covalently attach Abs to surfaces and subsequently release them with visible light (400-450 nm). The PC linker allowed rapid (2 min) and efficient (>90%) release of CTCs and EVs without damaging their molecular cargo.
- Brown, Virginia,Digamber, Rane,Givens, Richard S.,Jackson, J. Matt,Pahattuge, Thilanga N.,Perera, Chamani,Peterson, Blake R.,Soper, Steven A.,Wijerathne, Harshani,Witek, Malgorzata A.
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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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- Clean Adipic Acid Synthesis from Liquid-Phase Oxidation of Cyclohexanone and Cyclohexanol Using (NH4)xAyPMo12O40 (A: Sb, Sn, Bi) Mixed Heteropolysalts and Hydrogen Peroxide in Free Solvent
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Abstract: Clean synthesis of adipic acid (AA) from oxidation of cyclohexanone, cyclohexanol or mixture cyclohexanol/cyclohexanone, was carried out at 90?°C, in the presence of hydrogen peroxide (30%) in free solvent, using Keggin-type polyoxometalates, (NH4)xAyPMo12O40 (An+=Sb3+, Bi3+ or Sn2+), as catalysts. HPLC analysis of reaction mixture showed the formation of adipic, succinic and glutaric acids and unidentified products. The salts were found to be effective for AA synthesis. Whatever the composition of the catalyst, the alcohol oxidation favors the formation of the unidentified products, unlike the ketone oxidation which favors that of the adipic acid. (NH4)0.5Sn1.25PMo12O40 led to the highest AA yield (56%) from cyclohexanone oxidation, after 20?h of reaction. In addition, 31P NMR analysis showed that it has conserved the Keggin structure contrary to others catalysts and that it can be used at least 3 times with reaction times of 20?h, without regeneration. From different catalytic tests and 31P NMR data, reaction pathways have been proposed. The active species could be peroxo-polyoxometalates.
- Mouheb, Lynda,Dermeche, Leila,Mazari, Tassadit,Benadji, Siham,Essayem, Nadine,Rabia, Chérifa
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- Tungsten doped mesoporous SBA-16 as novel heterogeneous catalysts for oxidation of cyclopentene to glutaric acid
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Novel heterogeneous tungsten species in mesoporous silica SBA-16 catalysts based on ship-in-a-bottle methodology are originally reported for oxidizing cyclopentene (CPE) to glutaric acid (GAC) using hydrogen peroxide (H2O2). For all W-SBA-16 catalysts, isolated tungsten species and octahedrally coordinated tungsten oxide species are observed while WO3 crystallites are detected for the W-SBA-16 catalysts with Si/ W = 5, 10, and 20. The specific surface areas and the corresponding total pore volumes decrease significantly as increasing amounts of tungsten incorporated into the pores of SBA-16. Using tungsten-substituted mesoporous SBA-16 heterogeneous catalysts, high yield of GAC (55%) is achieved with low tungsten loading (for Si/W = 30, ~13?wt%) for oxidation of CPE. The W-SBA-16 catalysts with Si/W = 30 can be reused five times without dramatic deactivation. In fact, low catalytic activity provided by bulk WO3 implies that the highly distributed tungsten species in SBA-16 and the steric confinement effect of SBA-16 are key elements for the outstanding catalytic performance.
- Jin, Manman,Zhang, Guodi,Guo, Zhenmei,Lv, Zhiguo
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- Enantiotopically Selective Oxidation of α,ω-Diols with the Enzyme Systems of Microorganisms
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Gluconobacter were found to be capable of oxidizing prochiral diols such as 2-substituted propane-1,3-diols 1 and 3-substituted pentane-1,5-diols 4 with distinction of pro-R and pro-S sites of the molecules, in that (-)-(R)-α-substituted β-hydroxypropionic acids 2 and (+)-(3S)-3-substituted δ-valerolactones 5 were obtained, respectively.Oxidation of 3-methylpentane-1,3,5-triol 11 afforded unnatural (+)-(S)-mevalonolactone 12.The steric bulkiness of the substituents on the prochiral center and the distance from the hydroxy group greatly affected the rate and the enantioselectivity of the reaction.
- Ohta, Hiromichi,Tetsukawa, Hatsuki,Noto, Naoko
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- Metal ion catalysis in the hydrolysis of esters of 2-hydroxy-1, 10-phenanthroline: The effects of metal ions on intramolecular carboxyl group participation
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Rate constants have been determined for hydrolysis of the acetate, glutarate, and phthalate monoesters of 2-hydroxy-1,10-phenanthroline in water at 30°C and μ = 0.1 M with KCl. The hydrolysis reactions of the esters are hydroxide ion catalyzed at pH > 9. The phthalate and glutarate monoesters have in addition pH-independent reactions from pH 5.5 to 9 that involve intramolecular participation by the neighboring carboxylate anion. The pH-independent reaction of the glutarate monoester is ～5-fold faster than that of the phthalate monoester. The plots of log kobsd vs pH for hydrolysis of the carboxyl substituted esters are bell shaped at pH a rapid reaction of the zwitterionic species (carboxyl anion and protonated phenanthroline nitrogen). The divalent metal ions, Cu2+, Ni2+, Zn2+, and Co2+, complex strongly with the esters; saturation occurs at metal ion concentrations less than 0.01 M. The 1:1 metal ion complexes have greatly enhanced rates of hydrolysis; the second-order rate constants for the OH- reactions are increased by factors of 105 to 108 by the metal ion. The pH-rate constant profiles for the phthalate and glutarate ester metal ion complexes have a sigmoidal region below pH 6 that can be attributed to a metal ion-promoted carboxylate anion nucleophilic reaction. The carboxyl group reactions are enhanced 102- to 103-fold by the metal ions, which allows the neighboring group reaction to be competitive with the favorable metal ion-promoted OH- reaction at pH 6. The half-lives of the pH-independent neighboring carboxyl group reactions of the Cu(II) complexes at 30°C are ～2 s. The other metal ion complexes are only slightly less reactive (half-lives vary from 2.5 to 40 s). These are the most rapid neighboring carboxyl group reactions that have been observed in ester hydrolysis.
- Fife, Thomas H.,Pujari
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- MIL-101 metal-organic framework: A highly efficient heterogeneous catalyst for oxidative cleavage of alkenes with H2O2
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In the present work, a new and efficient method for direct oxidation of alkenes to carboxylic acids with H2O2 catalyzed by metal-organic framework MIL-101 is reported. In this transformation, the MIL-101 catalyzes the oxidation reactions by framework nodes and acts as a heterogeneous and reusable catalyst. The structure of MIL-101 was stable after three catalytic cycles.
- Saedi, Zahra,Tangestaninejad, Shahram,Moghadam, Majid,Mirkhani, Valiollah,Mohammadpoor-Baltork, Iraj
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- Efficient oxidation of alcohols to carbonyl compounds with molecular oxygen catalyzed by N-hydroxyphthalimide combined with a Co species
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Highly efficient catalytic oxidation of alcohols with molecular oxygen by N-hydroxyphthalimide (NHPI) combined with a Co species was developed. The oxidation of 2-octanol in the presence of catalytic amounts of NHPI and Co(OAc)2 under atmospheric dioxygen in AcOEt at 70 °C gave 2-octanone in 93% yield. The oxidation was significantly enhanced by adding a small amount of benzoic acid to proceed smoothly even at room temperature. Primary alcohols were oxidized by NHPI in the absence of any metal catalyst to form the corresponding carboxylic acids in good yields. In the oxidation of terminal vic-diols such as 1,2-butanediol, carbon-carbon bond cleavage was induced to give one carbon less carboxylic acids such as propionic acid, while internal vic-diols were selectively oxidized to 1,2-diketones.
- Iwahama, Takahiro,Yoshino, Yasushi,Keitoku, Takashi,Sakaguchi, Satoshi,Ishii, Yasutaka
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- Efficient synthesis of glutaric acid from L-glutamic acid via diazoniation/hydrogenation sequence
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The practical synthetic preparation of glutaric acid has remained a major challenge to date. In the present study, glutaric acid was synthesised by way of one-pot diazoniation/hydrogenation of the readily available L-glutamic acid under aqueous conditions on a gram-scale with good yields. This is the first example of the deamination of the aliphatic primary amine via diazoniation and could afford a practical approach to the production of glutaric acid.
- Zhang, Wei,Rao, Meng-Yun,Cheng, Zhong-Jun,Zhu, Xiao-Yan,Gao, Kai,Yang, Jian,Yang, Bo,Liao, Xia-Li
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- Oxidation reactions catalysed by titanium- and chromium-containing silicalites
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While the titanium silicalite-1 (TS-1)-tert-butyl hydroperoxide (TBHP) combination exhibits remarkable activity and selectivity in the oxidative cleavage of the C-C double bond of silyl enol ethers to produce dicarboxylic acids, the chemoselective oxidation of thioethers to sulfoxides without generation of sulfones is achieved using chromium silicalite-2 (CrS-2)-H2O2.
- Raju, Satya V. N.,Upadhya,Ponrathnam,Daniel,Sudalai
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- Oxidation of Cyclopentene by RuCl3-NaOCl Catalyst
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Oxidation of cyclopentene by RuCl3-NaOCl catalyst in an aqueous-organic two phase system was investigated by changing compositions of solvent system and additives to the aqueous solution.Use of acetonitrile as a cosolvent enhanced the reaction rate greatly, and addition of NaOH improved the yield of glutaric acid up to 80percent.
- Orita, Hideo,Hayakawa, Takashi,Takehira, Katsuomi
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- Bilayer MOF@MOF and MoOx species functionalization to access prominent stability and selectivity in cascade-selective biphase catalysis
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A novel bilayer metal-organic framework (viz., MOF@MOF, based on Zr-MOFs via epitaxial growth of UiO-bpy on preformed UiO-66) assembled with two-dimensional MoOx species was designed and synthesized. The MoOx@UiO-66@MoOx@UiO-bpy composite would improve substrates/products diffusion, avoid active metals leaching, and crucially provide a new platform via trapping intermediates and regulating the desired reaction direction. As confirmed via characterization results, MoOx@UiO-66@MoOx@UiO-bpy with micro-/mesopores and strong acid sites (Lewis and Br?nsted) exhibited good thermal and chemical stability. The bilayer MoOx@UiO-66@MoOx@UiO-bpy was further tested in cascade-selective biphase cyclopentene oxidation and exhibited 10.3% cyclopentene conversion and 16.9% glutaric acid selectivity higher than those of MoOx@UiO-66, due to its large specific surface area, high content of MoOx species, micro-/mesoporous structure, and bilayer catalytic effect. Its good reusability (> 10 runs) in the solvent-free-biphase cyclopentene oxidation suggested multidimensional encapsulation of active species in bilayer MOFs providing new idea for designing high-selectivity/stability heterogeneous catalysts. Besides, a set of reaction kinetic models with detailed kinetic parameters and a detailed reaction mechanism were provided, reconfirming the key to develop the technology of cyclopentene to glutaric acid was to conquer cyclopentene oxide hydrolysis activation energies (E2 and E4). Compared to our previous study, E2 and E4 values were decreased 93.8 and 31.7 kJ?mol?1, respectively.
- Han, Hong,Jin, Manman,Liu, Guodong,Lv, Zhiguo,Niu, Qingtao,Si, Chongdian
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- Novel photochemical reactions of carbocyclic diazodiketones without elimination of nitrogen – a suitable way to N-hydrazonation of C–H-bonds
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The sensitized photoexcitation of 2-diazocyclopentane-1,3-diones in the presence of THF leads to the insertion of the terminal N-atom of the diazo group into the α-С–Н bond of THF, producing the associated N-alkylhydrazones in yields of up to 63–71%. Further irradiation of hydrazones derived from furan-fused tricyclic diazocyclopentanediones culminates in the cycloelimination of furans to yield 2-N-(alkyl)hydrazone of cyclopentene-1,2,3-trione. By contrast, the direct photolysis of carbocyclic diazodiketones gives only Wolff rearrangement products with up to 90–97% yield.
- Rodina, Liudmila L.,Azarova, Xenia V.,Medvedev, Jury J.,Semenok, Dmitrij V.,Nikolaev, Valerij A.
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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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- The 2-oxocyclobutanecarboxylic acid keto-enol system in aqueous solution: A remarkable acid-strengthening effect of the cyclobutane ring
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Flash photolysis of 2-diazocyclopentane-1,3-dione in aqueous solution produced 2-oxocyclobutylideneketene, which underwent hydration to the enol of 2-oxocyclobutanecarboxylic acid; the enol then isomerized to the keto form of this acid. Rates of the ketene and enol reactions were measured in acid, base, and buffer solutions across the acidity range [H+] = 10 -1-10-13 M, and analysis of these data, together with rates of enolization of the keto form of 2-oxocyclobutanecarboxylic acid determined by bromine scavenging, gave keto-enol equilibrium constants as well as acidity constants of the keto and enol forms. The keto-enol equilibrium constants proved to be 2 orders of magnitude less than those reported previously for the next higher homolog, 2-oxocyclopentanecarboxylic acid, reflecting the difficulty of inserting a carbon-carbon double bond into a small, strained carbocyclic ring. The acidity constant of the enol group of 2- oxocyclobutanecarboxylate ion, on the other hand, is greater, by 4 orders of magnitude, than that of the corresponding enol in the cyclopentyl system. This remarkable increase in acidity with diminishing ring size is consistent with the enhanced s character of the orbitals used to make the exocyclic bonds of the smaller cyclobutane ring.
- Chang,Chiang,Keeffe,Kresge,Nikolaev,Popik
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- Osmium tetroxide-promoted catalytic oxidative cleavage of olefins: An organometallic ozonolysis
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A mild, organometallic alternative to ozonolysis utilizing oxone and OsO4 is presented. This is a direct oxidation of olefins via the carbon-carbon cleavage of an osmate ester by the action of oxone. Twenty-four different olefins were converted to their corresponding ketones or carboxylic acids in high yields (> 80%). Free alcohols, acetate- and benzyl-protected alcohols, and 1,2-diols were stable under these conditions. This method should be applicable for traditional organic synthesis. Copyright
- Travis, Benjamin R.,Narayan, Radha S.,Borhan, Babak
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- PHOTOSENSITIZED OXYGENATION OF THE ENOL FORMS OF 1,2-CYCLOHEXANEDIONES
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The enols of 1,2-cyclohexanediones have been found to undergo a photosensitized oxygenation in methanol to afford 5-oxoalkanoic acids and methyl 5-carboxy-2-hydroxypentanoates with liberation of carbon monoxide with a remarkable temperature dependency of the product distribution, which is best accounted for in terms of trapping of a five-membered endoperoxide intermediate by methanol.
- Utaka, Masanori,Nakatani, Manabu,Takeda, Akira
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- Alkene and alkyne oxidative cleavage catalyzed by RuO4 in environmentally acceptable solvents
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The application of CCl4, C6Hl2, EtOAc, and Me2CO as solvents for biphasic systems has been compared for oxidative cleavage of alkenes and alkynes by RuO4 to carboxylic acids, using the RuCl3·nH2O-IO(OH)5 reagent for which an improved procedure is described. Cyclohexane is an effective and economic replacement for the environmentally unfriendly CCl 4; acetone and ethyl acetate are less effective.
- Griffith, William P.,Kwong, Eugene
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- Role of added chloride ions in alteration of reaction pathway in the oxidation of cyclic ketones by dichloroisocyanuric acid - A kinetic study
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Effect of added chloride ions on kinetics and pathway of reaction between cyclic ketones (five to eight membered rings) and dichloroisocyanuric acid (DCICA) was studied in aqueous acetic acid - perchloric acid medium. Formation of aliphatic dicarboxylic acids as the end products demonstrates the ring cleavage oxidation. Positive effect of acid and negative effect of dielectric constant on the reaction rate reveals a interaction between positive ion (oxidant in the form of H2OCl+) and dipolar substrate molecule. Zero and first orders by oxidant in absence and presence of added chloride ions illustrates the participation of substrate as enolic form of ketone and protonated ketone, respectively, in the rate determining steps. The observed order of reactivity of cyclic ketones (cyclohexanone > cyclooctanone > cyclopentanone > cycloheptanone) was explained on the bases of ring strain, change of hybridization and conformational considerations. The envisaged plausible mechanism based on order of reactants in presence and absence of added chloride ions was substantiated by the order of Arrhenius parameters.
- Lakshman Kumar,Venkata Nadh,Radhakrishnamurti
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- Synthesis of an Isotopically Isomeric Mixture of 1,4,6,8-Tetramethyl2>azulene and Its Thermal Reaction with Dimethyl Acetylenedicarboxylate
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Sodium 2>cyclopentadienide in tetrahydrofuran (THF) has been prepared from the corresponding labelled 2>cyclopentadiene which was synthesized from 13CO2 and (chloromethyl)trimethylsilane (cf.Scheme 10) according to an established procedure.It could be shown that the acetate pyrolysis of cis-cyclopentane-1,2-diyl diacetate (cis-22) at 550 +/- 5 deg under reduced pressure (60 Torr) gives five times as much cyclopentadiene as trans-22.The reaction of sodium 2>cyclopentadienide with 2,4,6-trimethylpyrylium tetrafluoroborate in THF leads to the formation of the statistically expected 2:2:1 mixture of 4,6,8-trimethyl2>-, -2>-, and -2>azulene (20; cf.Scheme 7 and Fig. 1).Formylation and reduction of the 2:2:1 mixture 2>-20 results in the formation of a 1:1:1:1:1 mixture of 1,4,6,8-tetramethyl2>-, -2>-, -2>-, -2>-, and -2>azulene (5; cf.Scheme 8 and Fig. 2).The measured 2J(13C,13C) values of 2>-20 and 2>-5 are listed in Tables 1 and 2.Thermal reaction of the 1:1:1:1:1 mixture 2>-5 with the four-fold amound of dimethyl acetylenedicarboxylate (ADM) at 200 deg in tetralin (cf.Scheme 2) gave 5,6,8,10-tetramethyl-2>heptalene-1,2-dicarboxylate (2>-6a; 22percent), its double-bond-shifted (DBS) isomer 2>-6b (19percent), and the corresponding azulene-1,2-dicarboxylate 7 (18percent).The isotopically isomeric mixture of 2>-6a showed no 1J(13C,13C) at C(5) (cf.Fig. 3).This finding is in agreement with the fact that expected primary tricyclic intermediate 2>-8 exhibits at 200 deg in tetralin only cleavage of the C(1)-C(10) bond and formation of a C(7)-C(10) bond (cf.Schemes 6 and 9), but no cleavage of the C(1)-C(11) bond and formation of a C(7)-C(11)-bond.The limits of detection of the applied method is Y>/= 96percent for the observed process, i.e., 2>-5 + ADM -> 2>-8 -> 2>-9 -> 2>-6a (cf.Scheme 6).
- Fallahpour, Reza-Ali,Hansen, Hans-Juergen
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- Effects of counter cations in selective monohydrolyses of symmetric diesters
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Monohydrolyses of symmetric diesters were carried out using several aqueous inorganic bases, LiOH, NaOH, KOH, and CsOH. The more reactive bases showed higher selectivities in the monohydrolyses of acyclic symmetric diesters.
- Niwayama, Satomi,Rimkus, Audrius
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- Ruthenium(VIII) mediated oxidation of some aliphatic and alicyclic ketones by periodate-ruthenium(III) system in aqueous HClO4 medium
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The kinetics of Ruthenium(III) chloride mediated oxidation of acetone, 2-butanone, 4-methyl-2-pentanone, 2-pentanone, 2-pentanone, cyclopentanone, and cyclohexanone by sodium periodate in aqueous HClO4 media was zero-order in [IO4-] and first-order dependence on [H+] for all the ketones independent of added [Ru(III)] and showed first-order dependence on [H+] for all the ketones studied, except acetone. In the case of acetone at [H+] +], the order in [Ru(III)] being unity; but at [H+] > 0.05 M the reaction showed unit dependence on [H+] and the order in [Ru(III)] was zero. Ruthenium(VIII) generated in situ is postulated as the hydride abstracting species. A mechanism involving enolization as the rate determining step is proposed. Acetone at lower acidity of the medium is shown to react directly with Ru(VIII). In the absence of ruthenium(III) chloride, the kinetics were first-order in [IO4-], [ketone], and [H+]. Structure-reactivity relationship is discussed and thermodynamic parameters are reported.
- Panda,Pati
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- Kinetics of Electron Transfer from Cyclic Ketones to Ni(IV) Periodate Complex in Aqueous Alkaline Medium
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The kinetics of electron transfer from cyclic ketones (represented by (S)) to Ni(IV) periodate complexes has been studied in aqueous alkaline medium.The kinetics exhibit a pseudo-first-order disappearance of Ni(IV) periodate complexes when the is present in excess.The pseudo-first-order rate constants kobs, were linearly dependent on and the order is were found to be unity.The rate of the reaction increased with the increase in ->, however the rates were retarded with the increase in .Salt and solvent effect studies indicate that the reaction is of ion-dipole type.A suitable mechanism involving slow adduct formation between anol and oxidant, and its decomposition in a fast step have been suggested.A rate law consistent with the proposed mechanism has also been derived.The products of oxidation were identified as corresponding decarboxylic acids.
- Khan, Jaffar Ali,Chandraiah, U.,Kumar, B. Kishore,Kandlikar, Sushama
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- Efficient oxidative cleavage of 1,3-dicarbonyl derivatives with hydrogen peroxide catalyzed by quaternary ammonium iodide
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Quaternary ammonium iodide, a metal-free and mild catalyst, was proven to be a successful catalyst in the oxidative cleavage of 1,3-dicarbonyl derivatives with H2O2 as terminal oxidant. The mechanistic aspects of these "multistep" catalytic oxidations were discussed in terms of the catalytic cycle of the iodine species and the oxidative cleavage of the α carbon from the dicarbonyl compounds to generate the corresponding carboxylic acids.
- Yuan, Yu,Ji, Xiang,Zhao, Dongbo
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- Excellent synthesis of adipic acid
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A simple, straightforward, and environmentally benign protocol for the synthesis of adipic acid from oxidation of cyclohexanone with Oxone in the presence of 0.5mol% RuCl3·nH2O is reported. The reaction completes within a very short time even at room temperature. The generality of the method is shown successfully for synthesis of other C-5 to C-8 dicarboxylic acids.
- Rokhum, Lalthazuala,Bez, Ghanashyam
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- Automated on-line monitoring of the TiO2-based photocatalytic degradation of dimethyl phthalate and diethyl phthalate
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A fully automated on-line system for monitoring the TiO2-based photocatalytic degradation of dimethyl phthalate (DMP) and diethyl phthalate (DEP) using sequential injection analysis (SIA) coupled to liquid chromatography (LC) with UV detection was proposed. The effects of the type of catalyst (sol-gel, Degussa P25 and Hombikat), the amount of catalyst (0.5, 1.0 and 1.5 g L-1), and the solution pH (4, 7 and 10) were evaluated through a three-level fractional factorial design (FFD) to verify the influence of the factors on the response variable (degradation efficiency, %). As a result of FFD evaluation, the main factor that influences the process is the type of catalyst. Degradation percentages close to 100% under UV-vis radiation were reached using the two commercial TiO2 materials, which present mixed phases (anatase/rutile), Degussa P25 (82%/18%) and Hombikat (76%/24%). 60% degradation was obtained using the laboratory-made pure anatase crystalline TiO2 phase. The pH and amount of catalyst showed minimum significant effect on the degradation efficiencies of DMP and DEP. Greater degradation efficiency was achieved using Degussa P25 at pH 10 with 1.5 g L-1 catalyst dosage. Under these conditions, complete degradation and 92% mineralization were achieved after 300 min of reaction. Additionally, a drastic decrease in the concentration of BOD5 and COD was observed, which results in significant enhancement of their biodegradability obtaining a BOD5/COD index of 0.66 after the photocatalytic treatment. The main intermediate products found were dimethyl 4-hydroxyphthalate, 4-hydroxy-diethyl phthalate, phthalic acid and phthalic anhydride indicating that the photocatalytic degradation pathway involved the hydrolysis reaction of the aliphatic chain and hydroxylation of the aromatic ring, obtaining products with lower toxicity than the initial molecules.
- Salazar-Beltrán, Daniel,Hinojosa-Reyes, Laura,Maya-Alejandro, Fernando,Turnes-Palomino, Gemma,Palomino-Cabello, Carlos,Hernández-Ramírez, Aracely,Guzmán-Mar, Jorge Luis
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- Palladium Complexes with Bulky Diphosphine Ligands as Highly Selective Catalysts for the Synthesis of (Bio-) Adipic Acid from Pentenoic Acid Mixtures.
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A series of sterically bulky diphosphines have been prepared, including P2 = trans-1,2-bis[(di-tert-butylphosphino)methyl]cyclohexane (4), (2-methylenepropane-1,3-diyl)bis(di-tert-butylphosphine) (5), bis[(di-tert-butylphosphino)methyl]dimethylsilane (6), and cis- and trans-11,12-bis[(di-tert-butylphosphino)methyl]-9,10-dihydro-9,10-ethanoanthracene (10 and 11). The corresponding palladium complexes of these ligands, P2Pd(CF3CO2)2, have been synthesized and characterized. The solid-state structures of [Pd(4)(CF3CO2)2], [Pd(5)(CF3CO2)2], [Pd(6)(CF3CO2)2], and [Pd(11)(CF3CO2)2] were obtained by single-crystal X-ray diffraction and confirm the bidentate binding mode of the ligand and a square-planar coordination geometry with a minor distortion from the ideal. The diphosphines in combination with Pd(OAc)2 have been applied in the hydroxycarbonylation of a mixture of pentenoic acid isomers to produce adipic acid with high selectivity (in several cases >95%). The (regio)selectivity of the hydroxycarbonylation reaction is highly dependent on the P2 diphosphine ligand structure, particularly the steric bulk of the substituents on the diphosphine donor and the P-Pd-P bite angle in the complexes, with respectively tertiary alkyl phosphine substituents (tert-butyl, adamantyl) and a C4 backbone P-Pd-P bite angle >100° being the common features of highly adipic acid selective systems. It is suggested that the regioselectivity of hydroxycarbonylation becomes largely driven by the chelation of the carboxylic acid functionality of pentenoic acid substrates, when smaller size P substituents and/or when P2 ligands with smaller bite angles (100°) are applied.
- Low, Choon Heng,Nobbs, James D.,Van Meurs, Martin,Stubbs, Ludger P.,Drent, Eite,Aitipamula, Srinivasulu,Pung, Michelle H. L.
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- BACTERIA IN ORGANIC SYNTHESIS: SELECTIVE CONVERSION OF 1,3-DICYANOBENZENE INTO 3-CYANOBENZOIC ACID
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Suspensions of Rhodococcus rhodochrous NCIB 11,216 catalyse hydrolysis of dinitriles into cyanocarboxylic acids under mild conditions.This bioconversion was used for the highly selective synthesis of 3-cyanobenzoic acid from 1,3-dicyanobenzene.
- Bengis-Garber, Carmela,Gutman, Arie L.
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- Oxidation of cyclohexanone and/or cyclohexanol catalyzed by Dawson-type polyoxometalates using hydrogen peroxide
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The oxidation of cyclohexanone, cyclohexanol or cyclohexanone/cyclohexanol mixture using as catalyst, Dawson-type polyoxometalates (POMs) of formula, α- and β-K6P2W18O62, α-K6P2Mo6W12O62 and α1-K7P2Mo5VW12O62 and hydrogen peroxide, carried out at 90 °C with a reaction time of 20 h, led to a high number of mono- and di-acids which were identified by GC-MS. Levulinic, 6-hydroxyhexanoic, adipic, glutaric and succinic acids, major products were evaluated by HPLC. Regardless of the substrate nature, all POMs exhibited high catalytic activity with 94–99% of conversion, whereas the formation of the different products is sensitively related to both the composition and symmetry of the POMs and the substrate nature. The main products are adipic acid in the presence of α-K6P2Mo6W12O62 and α1-K7P2Mo5VW12O62, levulinic acid in the presence of α1-K7P2Mo5VW12O62 and β-K6P2W18O62 and 6-hydroxyhexanoic acid in the presence of α- and β-K6P2W18O62. Graphical abstract: High catalytic activity was observed with?α- and?β-K6P2W18O62, α-K6P2Mo6W12O62 and α1-K7P2Mo5VW12O62 Dawson-type for the oxidation of cyclohexanone, cyclohexanol or cyclohexanone/cyclohexanol mixture, in the hydrogen peroxide presence, to several oxygenated products. Adipic, levulinic and 6-hydroxyhexanoic acids are the main products. The peroxo- species formed in situ could be the active sites.[Figure not available: see fulltext.]
- Dermeche, Leila,Idrissou, Yasmina,Mazari, Tassadit,Moudjahed, Mohammed,Rabia, Cherifa
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- 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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- 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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- 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.
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Paragraph 0107; 0105; 0101; 0099; 0093; 0089; 0087; 0065;
(2021/05/21)
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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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- Catalytic Aerobic Oxidation of Lignocellulose-Derived Levulinic Acid in Aqueous Solution: A Novel Route to Synthesize Dicarboxylic Acids for Bio-Based Polymers
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The world is facing grand and ever-increasing pressures on energy and environmental issues. Using carbon-neutral biomass to prepare monomers such as dicarboxylic acids for degradable polymers is of great significance and an urgent but challenging task. Herein, we report a catalytic route for the synthesis of 2-hydroxy-2-methylsuccinic acid, an excellent monomer: e.g., it is able to remarkably enhance the comprehensive properties of polybutylene succinate as shown herein. By catalytic aerobic oxidation of levulinic acid, a bulk platform chemical derived from lignocellulose, the target product was obtained with a very high selectivity of up to ca. 95%. The mild reaction conditions below 100 °C in water and the low-cost reusable heterogeneous catalyst further make the process highly attractive for applications. This process was also found to be effective for the conversion of homologues of levulinic acid to dicarboxylic acids. We studied the C-C bond rearrangement and the roles of catalysts in the reaction that are highly likely involved in a superoxide anion radical mechanism. This study may provide inspiration for the synthesis of bio-based dicarboxylic acids via alternative routes.
- Che, Li,Jiang, Min,Jiang, Yu,Pang, Jifeng,Song, Lei,Wang, Rui,Zhang, Tao,Zhao, Yu,Zheng, Mingyuan,Zhou, Guangyuan,Zhou, Mo
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p. 11588 - 11596
(2021/09/22)
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- 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
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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)
-
- 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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- 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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- Synthesis of N-unsubstituted cyclic imides from anhydride with urea in deep eutectic solvent (DES) choline chloride/urea
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N-Unsubstituted cyclic imides were readily synthesized in deep eutectic solvent (DES) choline chloride (ChCl)/urea from anhydrides with urea. Urea serves as both a DES component and a nitrogen source, which endows the protocol with advantages of smooth reaction, easy separation of products, simple recovery and recycling of ChCl/urea.
- Liu, Luxiao,Zhang, Hong-Yu,Yin, Guohui,Zhang, Yuecheng,Zhao, Jiquan
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p. 1351 - 1357
(2019/11/19)
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- 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.
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Paragraph 0109-0110
(2020/04/17)
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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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Paragraph 0067; 0068
(2020/05/01)
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- 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 0041-0042
(2020/12/10)
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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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- 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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- Novel method with mild reaction conditions for catalytic oxidation of cyclopentane
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The invention discloses a method for catalytic oxidation of cyclopentane. The method comprises the following steps: mixing metalloporphyrin and the cyclopentane, performing a reaction for 2-48 h at atemperature of 100-150 DEG C and O2 pressure of 0.6-2 MPa, performing post-treatment on the reaction liquid, and performing separation to obtain oxidation product glutaric acid, cyclopentanol and cyclopentanone. The novel method for the catalytic oxidation of the cyclopentane provided by the invention has low reaction temperature and a less catalyst use amount, uses O2 as an oxidant, is green andenvironmentally friendly, and can highly selectively oxidize the cyclopentane into the cyclopentanol, the cyclopentanone and the glutaric acid; and the novel method for the catalytic oxidation of thecyclopentane has the advantages of simple operation, no use of organic solvents, high selectivity of the glutaric acid, a low hydrogen oxide content of cyclopentyl and the like.
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Paragraph 0027; 0028; 0031; 0032
(2019/04/26)
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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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- Aerobic oxidation of C4-C6 α,ω-diols to the diacids in base-free medium over zirconia-supported (bi)metallic catalysts
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Oxidation of aliphatic α,ω-diols is a potentially interesting route to the production of valuable α,ω-diacids or ω-hydroxy acids for various polymer synthesis. 1,4-Butanediol (BDO), 1,5-pentanediol (PDO) and 1,6-hexanediol (HDO) are particularly attractive since they may be obtained from lignocellulosic biomass. The aqueous aerobic oxidation of these diols to the corresponding diacids was investigated in water over a set of Au, Pt, Au-Pt and Au-Pd catalysts supported on zirconia at 70 °C or 90 °C under 40 bar air. The nature of the metallic catalyst influenced the distribution of products as oxidation proceeded. The longer the carbon chain linking the terminal alcohol groups, the higher the yield of the diacid. The best yields of succinic acid, glutaric acid and adipic acid reached 83, 84 and 96% from BDO, PDO and HDO, respectively, over Au-Pt/ZrO2. There was some evidence of decarbonylation of the α,ω-hydroxyaldehyde at the early stage of the reaction. The presence of the hydroxyl substituent in 1,2,6-hexanetriol significantly slowed the oxidation rates compared with HDO. Besides, oxidation of PDO or HDO was highly selective to the ω-hydroxycarboxylate in moderate alkaline medium (NaOH/diol = 2) over Au/ZrO2 (90-93%).
- Mounguengui-Diallo, Modibo,Sadier, Achraf,Da Silva Perez, Denilson,Nikitine, Clémence,Puchot, Laura,Habibi, Youssef,Pinel, Catherine,Perret, Noémie,Besson, Michèle
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p. 9873 - 9885
(2019/07/04)
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- Method for α- synthesizing glutaric acid from glutaric acid
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The invention relates to a method for synthesizing glutaric acid from alpha-ketoglutaric acid. Specifically, under the mild condition, protected ketone thioacetal is subjected to catalytic hydrogenation reduction with raney nickel, recycling and reusing of reactants, solvent and a catalyst are achieved in a carbonyl reduction part in the most critical step, and the method for preparing the largely-demanded glutaric acid with the simple four-step method is developed. According to the method, the glutaric acid with the high yield is synthesized with the method for the first time, the yields of all steps are 92%, 78.6%, 90% and 85% in sequence, and the total yield is 55.32%; the method has broad prospects in synthetic application of compound library establishment.
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- Method for preparing naphthenic alcohol and naphthenone by using molecular oxygen to selectively oxidize naphthenic hydrocarbon under synergistic catalysis of cobalt (II) salt/copper (II) salt
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The invention provides a method for preparing naphthenic alcohol and naphthenone by using molecular oxygen to selectively oxidize naphthenic hydrocarbon under synergistic catalysis of a cobalt (II) salt/copper (II) salt. The method comprises the following steps: in an agate ball-milling tank, ball-milling a main catalyst cobalt (II) salt and a cocatalyst copper (II) salt at room temperature according to a molar ratio to obtain a cobalt (II) salt/copper (II) salt composite catalyst; in a stainless steel high-pressure reaction kettle with a polytetrafluoroethylene liner, dispersing the cobalt (II) salt/copper (II) salt composite catalyst into the naphthenic hydrocarbon, sealing the reaction kettle, conducting stirring and heating, and introducing an oxidizing agent oxygen; maintaining a settemperature and oxygen pressure to perform stirring reaction; and after the reaction, adding triphenylphosphine into a reaction mixture, and conducting stirring to reduce a generated peroxide at roomtemperature, so as to obtain the naphthenic alcohol and the naphthenone. The catalyst is cheap and easily available and the synthesis cost is low; the selectivity is high and generation of aliphatic diacid is effectively inhibited; and the aliphatic diacid selectivity is low, and continuity of the naphthenic hydrocarbon oxidization process and separation of products are facilitated.
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Paragraph 0110-0115
(2020/01/03)
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- Method for synergistically catalyzing and oxidizing cycloalkane by porphyrin cobalt (II)/zinc (II) salt
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The invention discloses a method for synergistically catalyzing and oxidizing cycloalkane by porphyrin cobalt (II)/zinc (II) salt. The method comprises the following steps: dispersing porphyrin cobalt(II) and a zinc (II) salt in cycloalkane, sealing the reaction system, carrying out heating to 100-130 DEG C while stirring, introducing oxygen to 0.2-3 MPa, keeping a set temperature and oxygen pressure, carrying out stirring for reacting for 3-24 hours, and then carrying out after-treatment on the reaction solution to obtain product naphthenic alcohol and naphthenic ketone. According to the method disclosed by the invention, the naphthenic alcohol and the naphthenic ketone are high in selectivity, and generation of aliphatic diacid is effectively inhibited; a cocatalyst is cheap and is easily available, and synthesis cost of the naphthenic alcohol and naphthenic ketone is low; the aliphatic diacid is low in selectivity, so that continuity of a cycloalkane oxidation process and separation of products are facilitated; and the method has a potential of solving the problem that naphthenic alcohol and naphthenic ketone are easily and deeply oxidized to generate aliphatic diacid in industrial cycloalkane catalytic oxidation processes. The method is a novel efficient feasible method for selective catalytic oxidation of cycloalkane.
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Paragraph 0083; 0084
(2019/12/25)
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- Method for (II) preparing/cycloalkanol and cycloalkanone by synergetic (II) catalysis of molecular oxygen-selective oxidation of cycloalkane by using cobalt salt, namely, zinc salt of zinc salt (by machine translation)
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In a stainless steel (II) high /(II) pressure reaction kettle with a polytetrafluoroethylene inner container, the cobalt salt is stirred and heated at room temperature to give an oxidant oxygen (II); a set temperature (II) and an oxygen pressure stirring reaction are kept; and the reaction (II) mixture/is (II) stirred and reduced to generate a peroxide, namely cycloalkanol and cycloalkanone (II)/(II). The catalyst has the advantages of cheap and easily available catalyst, low synthesis cost, high selectivity, effective inhibition of generation of aliphatic diacid, low selectivity of aliphatic diacid, and facilitation of serialization of the naphthenic acid process and separation of products. (by machine translation)
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Paragraph 0101-0102
(2019/12/08)
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- Method for preparing carboxylic acid compound by oxidatively breaking carbon-carbon bond of ketone compound
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The invention relates to a method for directly preparing a carboxylic acid compound by oxidatively breaking a carbon-carbon bond of a ketone compound. The method comprises adding a ketone compound anda catalyst into an organic solvent, putting the solution into a pressure container, sealing the container, and feeding oxygen source gas under a certain pressure into the container, wherein the reaction product is a carboxylic acid compound, the oxygen source gas is oxygen or air, the catalyst is a copper salt catalyst, the organic solvent is one of acetonitrile, dimethyl sulfoxide and N, N-dimethylformamide and the corresponding carboxylic acid product highest yield after the reaction is 99%. The method has a wide application range, is free of alkali assistants and organic ligands and is easy to separate.
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Paragraph 0143; 0144
(2018/06/16)
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- The oxidative cleavage of trans-1,2-cyclohexanediol with O2: Catalysis by supported Au nanoparticles
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This paper reports on the catalytic oxidative cleavage of trans-1,2-cyclohexanediol with air, catalysed by supported Au NPs, as one of the steps of a new adipic acid synthesis process. Catalysts proved to be active, with a moderate cyclohexanediol conversion and selectivity to adipic acid close to 70%. The reaction network included several steps in sequence, amongst which the key one is the oxidation of the diol into 2-hydroxycylohexanone, which is then oxidised by air – even in the absence of a catalyst – to adipic acid and lesser amounts of lighter acids, i.e. glutaric and succinic acids. The oxidation of the second hydroxyl moiety in the diol would lead to the formation of 1,2-cyclohexanedione. The latter, however, is rapidly transformed into several by-products, especially glutaric acid, under the basic conditions which are necessary for allowing the reaction to occur at an acceptable rate. With Au-based catalysts, this undesired reaction occurs much more slowly than with the previously investigated Ru hydroxide catalysts. The nature of the support, either TiO2 or MgO, also affected catalytic performance; the best performance was shown by the Au/MgO catalyst which, however, suffered from a remarkable deactivation, found to be due to both the increase in NPs size and the formation of carbonaceous residua on the catalyst surface.
- Solmi, Stefania,Rozhko, Elena,Malmusi, Andrea,Tabanelli, Tommaso,Albonetti, Stefania,Basile, Francesco,Agnoli, Stefano,Cavani, Fabrizio
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-
- Silver(I)-Catalyzed Widely Applicable Aerobic 1,2-Diol Oxidative Cleavage
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The oxidative cleavage of 1,2-diols is a fundamental organic transformation. The stoichiometric oxidants that are still predominantly used for such oxidative cleavage, such as H5IO6, Pb(OAc)4, and KMnO4, generate stoichiometric hazardous waste. Herein, we describe a widely applicable and highly selective silver(I)-catalyzed oxidative cleavage of 1,2-diols that consumes atmospheric oxygen as the sole oxidant, thus serving as a potentially greener alternative to the classical transformations.
- Zhou, Zhong-Zhen,Liu, Mingxin,Lv, Leiyang,Li, Chao-Jun
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supporting information
p. 2616 - 2620
(2018/02/13)
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- Cyclohexane Oxidation to Adipic Acid Under Green Conditions: A Scalable and Sustainable Process
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This work reports a 1 mol scale catalytic process to synthesize adipic acid directly from cyclohexane in solvent-free conditions using air as oxidant. Catalysts based on vanadium phosphorus oxides were prepared, characterized and tested. They showed good activity and remarkably high selectivity to adipic acid in comparison to other already known heterogeneous catalysts. The use of solvent-free conditions permits the easy separation of the product from the reactant mixture, which is very important from the industrial point of view. The process can be used at industrial scale for sustainable adipic acid synthesis.
- Mazzi, Alberto,Paul, Sébastien,Cavani, Fabrizio,Wojcieszak, Robert
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p. 3680 - 3682
(2018/09/12)
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- Metal-Free Synthesis of Adipic Acid via Organocatalytic Direct Oxidation of Cyclohexane under Ambient Temperature and Pressure
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A direct metal-free approach for the production of adipic acid from cyclohexane is reported. The use of N-hydroxyphthalimide (NHPI) as a catalyst in the presence of HNO3/TFA enables the direct oxidation of cyclohexane to yield adipic acid under ambient temperature and pressure via a simple procedure. This reaction proceeds through an initial oxidation of cyclohexane to cyclohexanone oxime and cyclohexanone followed by a second oxidation of these intermediates to adipic acid. NHPI plays a crucial role in both oxidation steps to achieve a high yield and selectivity for adipic acid.
- Matsumoto, Yohei,Kuriyama, Masami,Yamamoto, Kosuke,Nishida, Koyo,Onomura, Osamu
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supporting information
p. 1312 - 1317
(2018/09/25)
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- Mesoporous silica as phase transfer agent in the biphasic oxidative cleavage of alkenes using triazole complexes of ruthenium as catalyst precursors
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The oxidative cleavage of alkenes was performed using ruthenium triazole -arene complexes immobilized on mesoporous silica materials. These silica-organometallic hybrid materials were found to show enhanced activity when compared to conventional homogeneous systems even when operating at a relatively low catalyst loading. The enhanced catalytic performance of these heterogeneous systems can be attributed to the mesoporous silica acting as a phase transfer agent in the biphasic catalyst system.
- Leckie, Laura,Mapolie, Selwyn F.
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- The aliphatic dicarboxylic acid compound (by machine translation)
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PROBLEM TO BE SOLVED: To obtain an aliphatic dicarboxylic acid compound industrially useful as a monomer for high molecular compounds in a high yield and good selectivity under mild conditions.SOLUTION: An aliphatic cyclic hydrocarbon compound such as cyclohexane is efficiently oxidized into an aliphatic dicarboxylic acid compound by oxidizing the aliphatic cyclic hydrocarbon compound with nitric acid or a nitrate, in the presence of trifluoroacetic acid and an N-hydroxyimide compound. When an aliphatic cyclic hydrocarbon compound having a symmetric structure is adopted as a raw material, the obtained aliphatic dicarboxylic acid compound is single.
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Paragraph 0040; 0049; 0050
(2017/08/02)
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- Efficient and selective oxidation of aldehydes with dioxygen catalysed by vanadium-containing heteropolyanions
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The heteropolyacids “H3+n[PMo12–nVnO40]·aq” (denoted as HPA-n; n = 2, 3, 8) catalyse the oxidation of aldehydes to carboxylic acids in the presence of dioxygen with very good yields. The effect on the catalytic activity of various parameters such as the precursors, solvent, temperature or catalyst/substrate ratio was examined. The process is particularly selective for linear and aromatic aldehydes. The oxidation of adipaldehyde with dioxygen in mild conditions, in the presence of HPA-2 as a catalyst, leads to the formation of adipic acid together with a significant amount of other byproducts. Thus, several modifications of the catalytic systems have been carried out to improve their selectivity. The effect of cocatalysts was investigated and, among the species tested, complex Ni(acac)2 was found to be the most efficient yielding 60% of adipic acid.
- El Amrani, Ikram,Atlamsani, Ahmed,Dakkach, Mohamed,Rodríguez, Montserrat,Romero, Isabel,Amthiou, Souad
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p. 888 - 895
(2017/09/26)
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- Degradation of a cationic dye (Rhodamine 6G) using hydrodynamic cavitation coupled with other oxidative agents: Reaction mechanism and pathway
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In the present study, decolorization and mineralization of a cationic dye, Rhodamine 6G (Rh6G), has been carried out using hydrodynamic cavitation (HC). Two cavitating devices such as slit and circular venturi were used to generate cavitation in HC reactor. The process parameters such as initial dye concentration, solution pH, operating inlet pressure, and cavitation number were investigated in detail to evaluate their effects on the decolorization efficiency of Rh6G. Decolorization of Rh6G was marginally higher in the case of slit venturi as compared to circular venturi. The kinetic study showed that decolorization and mineralization of the dye fitted first-order kinetics. The loadings of H2O2 and ozone have been optimized to intensify the decolorization and mineralization efficiency of Rh6G using HC. Nearly 54% decolorization of Rh6G was obtained using a combination of HC and H2O2 at a dye to H2O2 molar ratio of 1:30. The combination of HC with ozone resulted in 100% decolorization in almost 5-10 min of processing time depending upon the initial dye concentration. To quantify the extent of mineralization, total organic carbon (TOC) analysis was also performed using various processes and almost 84% TOC removal was obtained using HC coupled with 3 g/h of ozone. The degradation by-products formed during the complete degradation process were qualitatively identified by liquid chromatography-mass spectrometry (LC-MS) and a detailed degradation pathway has been proposed.
- Rajoriya, Sunil,Bargole, Swapnil,Saharan, Virendra Kumar
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p. 183 - 194
(2016/06/06)
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- Metal-catalyzed reductive deamination of glutamic acid to bio-based dimethyl glutarate and methylamines
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Glutamic acid is a promising renewable platform molecule which is abundantly available in biomass waste streams; it is also efficiently manufactured by fermentation. Here we report the reductive deamination of glutamic acid to bio-based dimethyl glutarate and methylamines. In order to recycle nitrogen in an industrially relevant co-product, glutamic acid was modified to N,N-dimethylglutamic acid by a mild reductive alkylation with Pd/C. Subsequently, selective C-N hydrogenolysis in methanol resulted in dimethyl glutarate and trimethylamine. A wide screening of transition metals (Pt, Pd, Rh and Ru) immobilized on various supports showed that the highest yields of dimethyl glutarate were obtained with Pt/TiO2. An FTIR study and kinetic experiments on metal-loaded and unloaded supports demonstrate that the interplay between the metal and the moderate acidity of the support results in the excellent C-N hydrogenolysis activity and selectivity. Finally, reaction parameter optimization resulted in 81% yield of dimethyl glutarate with 1 wt% Pt/TiO2 at 225 °C, 30 bar H2 after 8 h.
- De Schouwer, Free,Cuypers, Thomas,Claes, Laurens,De Vos, Dirk E.
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supporting information
p. 1866 - 1876
(2017/06/09)
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- Preparation method of carboxylic acid compound
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The invention provides a preparation method of a carboxylic acid compound. The preparation method comprises the following step of taking a lactone component to react with hydrogen in the presence of a compound catalyst to obtain the carboxylic acid compound. The compound catalyst comprises a hydrogenation catalyst and Lewis acid. In the presence of the compound catalyst comprising the hydrogenation catalyst and the Lewis acid, the lactone component is subjected to hydrogenation ring-opening reaction to obtain the carboxylic acid compound. The preparation method has the advantages of moderate reaction conditions and high yield; compared with a traditional method, less byproducts are generated, green and chemical requirements are met and the industrial value is better.
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Paragraph 0113; 0231-0233
(2017/08/29)
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- A Comprehensive Study on Metal Triflate-Promoted Hydrogenolysis of Lactones to Carboxylic Acids: From Synthetic and Mechanistic Perspectives
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Direct hydrogenolysis of lactone to carboxylic acid (i.e., hydrogenolysis of the Calkoxy-O bond with the carbonyl group untouched) is generally difficult, as the current strategies employing Br?nsted acids as the catalyst usually require harsh conditions such as a high temperature and a high H2 pressure. Herein, we report a developed solvent-free catalytic transformation, in which W(OTf)6 is believed to promote the hydrogenolysis process. This strategy could efficiently hydrogenate lactones to carboxylic acids under extra mild conditions (e.g., a reaction temperature of 2) and showed a broad substrate scope. In addition, the catalytic protocol can be further applied to the hydrogenolysis of polyhydroxyalkanoate, as a renewable polymer, to the corresponding straight-chain carboxylic acids. An extensive mechanistic study was subsequently performed, and the density functional theory calculations revealed a reaction pattern, including the complete cleavage of the C=O bond with the assistance of the W(OTf)6 catalyst. Moreover, the key intermediate created in the mechanism, as an oxonium with an OTf moiety, was successfully detected by electrospray ionization mass spectra. Through a comparison with the Br?nsted acid-catalyzed system, the study confirmed that the existence of the OTf moiety can significantly lower the barriers associated with the rearrangement and elimination processes. Meanwhile, emphasis was placed on the critical role that the anion plays, as well as the fact that the anion effect is directly related to the chemoselectivity.
- Zhu, Rui,Jiang, Ju-Long,Li, Xing-Long,Deng, Jin,Fu, Yao
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p. 7520 - 7528
(2017/11/10)
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- Oxidative C?C Cleavage of Ketols over Vanadium–Carbon Catalysts
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The oxidation of 2-hydroxycyclohexanone and carbohydrates to adipic acid and formic acid, respectively, was performed with a combination of a vanadium catalyst, carbon as the cocatalyst, and O2 in water under mild conditions (353 K, 0.1–0.3 MPa). The catalytic activity of aqueous V2O5 was increased significantly by the addition of activated carbon (C), whereas the addition of carbon black, graphene oxide, and carbon nanotubes has a much smaller effect. UV/Vis and inductively coupled plasma optical emission spectroscopy were used to show that most VV species are adsorbed on C at least in a short reaction time. The VIV species (VO2+) was not adsorbed on C. The order of activity of vanadium species was VV on C>dissolved free VV?dissolved free VIV. To help the oxidation of VIV, the further addition of phosphomolybdate (PMo12O40 3?; PMo) was also tested, and the activity was improved. The selectivity and yield of adipic acid from 2-hydroxycyclohexanone was also improved slightly by the addition of PMo. However, in the oxidation of glucose, the addition of PMo did not improve the final formic acid yield. The oxidation of glucose with the V+C system gave a 42 % yield of formic acid, which was comparable to the values reported with a more expensive PVMo polyoxometalate catalyst. A reaction mechanism is proposed in which the reversibly formed “biradical” state of the vanadium ketol complex reacts with O2 and accompanying rearrangement dissociates the C?C bond.
- Nakagawa, Yoshinao,Sekine, Dai,Obara, Naoyuki,Tamura, Masazumi,Tomishige, Keiichi
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p. 3412 - 3419
(2017/09/06)
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- Reaction by-product by the oxidation of cyclohexane preparation of adipic acid and C * dibasic acid method
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The invention belongs to the technical field of organic synthesis and particularly relates to a method for preparing adipic acid and C4-6-dibasic acid from a cyclohexane oxidation reaction byproduct, aiming at solving the technical problem that the method for preparing adipic acid and C4-6-dibasic acid from the cyclohexane oxidation reaction byproduct can be used for preparing adipic acid and C4-6-dibasic acid by taking the cyclohexane oxidation reaction byproduct as a raw material. The technical scheme is as follows: the method for preparing adipic acid and C4-6-dibasic acid from the cyclohexane oxidation reaction byproduct comprises the following steps of a, separating the byproduct contained in cyclohexane oxidation reaction liquid; b, transforming the byproduct into adipic acid and C4-6-dibasic acid; c, separating and recovering adipic acid and C4-6-dibasic acid. The method disclosed by the invention can be used for separating the byproduct generated in the process of a cyclohexane air oxidation-alkaline saponification decomposition process and successfully transforming into important chemical products, namely adipic acid and C4-6-dibasic acid and achieves the effects of reducing consumption, reducing emission, sufficiently utilizing resources and changing wastes into valuables.
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Paragraph 0038-0041
(2017/05/12)
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- PREPARATION METHOD OF CARBOXYLIC ACIDS OR KETONES USING OZONE, SINGLET STATE-OXYGEN ATOM OR HYDROXYL FREE RADICAL
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A preparation method of carboxylic acids or ketones using ozone, singlet state oxygen atom O(1D) or hydroxyl free radical is provided. The method includes: filling ozone, singlet state oxygen atom O(1D) and/or hydroxyl free radical to cycloalkanes or benzenes at a pre-determined temperature and a pre-determined pressure in the presence or absence of light irradiation to produce carboxylic acids or ketones. The reaction occurs at room temperature and atmospheric pressure without producing harmful side products. The preparation method is a simple, low energy consuming, and eco-friendly method.
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Paragraph 0034; 0039
(2016/05/10)
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- Selective cyclohexane oxidation catalyzed by manganese porphyrins and co-catalysts
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Several polar molecules, such as alcohols, ketones, esters and acids, were used as co-catalysts for the cyclohexane oxidation catalyzed by manganese porphyrins, and the catalytic activity was found to be closely related to polarity of co-catalysts. The results indicated that the total selectivity of products was as high as 96.3% and glutaric acid selectivity was up to 50.9%. Thus, the proposed method provides a new approach for preparing glutaric acid.
- Wang, Tao,She, Yuanbin,Fu, Haiyan,Li, Hui
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p. 185 - 190
(2016/03/19)
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- Boosting one-step conversion of cyclohexane to adipic acid by NO2 and VPO composite catalysts
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We demonstrate VPO composites as efficient catalysts for highly selective oxidation of cyclohexane to adipic acid with NO2. In particular, the Ni-Al-VPO composite catalyst exhibits the striking conversion of cyclohexane (60.6%) and exceptionally high selectivity towards adipic acid (85.0%). Moreover, N2O is an environmentally harmful gas, and its yield in the present process is only 0.03 t/t adipic acid, which is far below that obtained using the industrial method (0.3 t/t adipic acid). This work provides a new strategy for the one-step synthesis of dicarboxylic acids from cycloalkanes.
- Jian, Jian,You, Kuiyi,Duan, Xuezhi,Gao, Hongxu,Luo, Qing,Deng, Renjie,Liu, Pingle,Ai, Qiuhong,Luo, He'an
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supporting information
p. 3320 - 3323
(2016/02/27)
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- Oxidative Cleavage of Vicinal Diols with the Combination of Platinum and Vanadium Catalysts and Molecular Oxygen
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The combination of Pt/C and V2O5 catalysts gave good performance for the oxidative cleavage of trans-1,2-cyclohexanediol into adipic acid via 2-hydroxycyclohexanone. The yield of adipic acid reached 90 % in the one-pot oxidative cleavage of trans-1,2-cyclohexanediol. The yield was higher than that obtained in the oxidation of 2-hydroxycyclohexanone with V catalyst, and the higher yield was due to the low 2-hydroxycyclohexanone concentration during the one-pot oxidation of trans-1,2-cyclohexanediol. Cyclic vicinal diols having a six-membered ring and linear vicinal diols having two secondary OH groups were converted into dicarboxylic acids and two carboxylic acids, respectively. The activity of the Pt catalyst decreased during the reaction, and the activity was partially restored by treating the used catalyst with H2 at 573K. Even without regeneration, the turnover number based on total Pt could reach ≈1000 in a long reaction with an increased amount of trans-1,2-cyclohexanediol.
- Obara, Naoyuki,Hirasawa, Shota,Tamura, Masazumi,Nakagawa, Yoshinao,Tomishige, Keiichi
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p. 1732 - 1738
(2016/05/19)
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- METHOD FOR HYDROLYSIS OF ALGINATE
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Provided is a method for decomposing alginate. The method for decomposing alginate comprises a step of conducting a decomposition reaction of alginate using a solid acid catalyst in water. The solid acid catalyst is a carbon catalyst having a sulfonic acid functional group. According to an embodiment of the present invention, alginate can be decomposed in an environment-friendly way without using sulfuric acid. Also, mannuronic acid and guluronic acid are formed by the decomposition of alginate.
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Paragraph 0035-0037; 0039; 0041
(2017/09/26)
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