- NOUVELLES METHODES DE DESHALOGENATION ET DE FORMATION D'ETHERS D'ENOL TRIMETHYLSILYQUES PAR ACTION DE iPr2NLi SUR QUELQUES α-BROMOCETONES
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iPr2NLi reacts with substituted α-bromoketones to yield the debrominated ketone after hydrolysis or the TMS-enol ether after addition of SiMe3Cl.Both reactions are quantitative within a few minutes.
- Dubois, Jacques-Emile,Lion, Claude,Dugast, Jean-Yves
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Read Online
- METHOD FOR PRODUCING CARBONATE DERIVATIVE
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The objective of the present invention is to provide a method for producing a polycarbonate safely and efficiently even without using a base. The method for producing a carbonate derivative according to the present invention is characterized in comprising the step of irradiating a high energy light to a composition comprising the halogenated methane and the hydroxy group-containing compound in the presence of oxygen, wherein a molar ratio of a total usage amount of the hydroxy group-containing compound to 1 mole of the halogenated methane is 0.05 or more.
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Paragraph 0122-0123
(2022/01/04)
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- Base-free oxidation of alcohols enabled by nickel(ii)-catalyzed transfer dehydrogenation
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An efficient nickel(ii)-catalyzed transfer dehydrogenation oxidation of alcohols is reported that relies on cyclohexanone as the formal oxidant and does not require the use of an external base. The synthetic utility of this protocol is demonstratedviathe facile oxidation of structurally complicated natural products.
- Ye, Danfeng,Liu, Zhiyuan,Sessler, Jonathan L.,Lei, Chuanhu
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supporting information
p. 11811 - 11814
(2020/10/13)
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- Chemoselective Oxidation of Equatorial Alcohols with N-Ligated λ3-Iodanes
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The site-selective and chemoselective functionalization of alcohols in complex polyols remains a formidable synthetic challenge. Whereas significant advancements have been made in selective derivatization at the oxygen center, chemoselective oxidation to the corresponding carbonyls is less developed. In cyclic systems, whereas the selective oxidation of axial alcohols is well known, a complementary equatorial selective process has not yet been reported. Herein we report the utility of nitrogen-ligated (bis)cationic λ3-iodanes (N-HVIs) for alcohol oxidation and their unprecedented levels of selectivity for the oxidation of equatorial over axial alcohols. The conditions are mild, and the simple pyridine-ligated reagent (Py-HVI) is readily synthesized from commercial PhI(OAc)2 and can be either isolated or generated in situ. Conformational selectivity is demonstrated in both flexible 1,2-substituted cyclohexanols and rigid polyol scaffolds, providing chemists with a novel tool for chemoselective oxidation.
- Mikhael, Myriam,Adler, Sophia A.,Wengryniuk, Sarah E.
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supporting information
p. 5889 - 5893
(2019/08/26)
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- Rhodium-Catalyzed Reductive Cleavage of Aryl Carbamates Using Isopropanol as a Reductant
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Despite the widespread use of carbamates as a directing group in C-H bond-functionalization reactions, reductive removal of this directing group is not straightforward. Currently available methods are limited to nickel-catalyzed reactions using i PrMgX or hydrosilane as a reductant, leaving the functional group compatibility issue to be solved. Herein, we report rhodium-catalyzed reductive cleavage of aryl carbamates using i PrOH as a milder reductant.
- Yasui, Kosuke,Higashino, Masaya,Chatani, Naoto,Tobisu, Mamoru
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supporting information
p. 2569 - 2572
(2017/10/06)
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- BRIDGED PHTHALOCYANINE- AND NAPTHTHALOCYANINE-METAL COMPLEX CATALYSTS AND METHODS OF USING AND PURIFYING THE SAME
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Various embodiments disclosed relate to bridged phthalocyanine- and napththalocyanine-metal complex catalysts and methods of using and purifying the same. In various embodiments, the present invention provides a method of purifying a catalyst. The method includes contacting a catalyst composition with acid, the catalyst composition including a catalyst, to provide an acidified catalyst composition with the catalyst dissolved therein. The method includes precipitating the catalyst, and removing the precipitated catalyst from solution, to provide a purified catalyst.
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Paragraph 0091; 0110
(2017/02/24)
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- Syndiotactic Poly(aminostyrene)-Supported Palladium Catalyst for Ketone Methylation with Methanol
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Palladium nanoparticles immobilized on an amino-functionalized syndiotactic polystyrene (sPS-N) served as a novel recyclable catalyst for the dimethylation and cross methyl alkylation of a wide range of ketones with methanol as the methylation agent. This heterogeneous catalyst (Pd@sPS-N) was highly robust and showed excellent thermal stability and chemical resistance. It not only showed remarkably high activity, but it could also be easily recovered by filtration without loss of activity.
- Jiang, Lei,Guo, Fang,Shi, Zhenghai,Li, Yang,Hou, Zhaomin
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p. 3827 - 3832
(2017/09/25)
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- A highly efficient palladium(ii)/polyoxometalate catalyst system for aerobic oxidation of alcohols
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A simple catalyst system composed of Pd(OAc)2, phosphomolybdic acid and tetrabutylammonium acetate oxidises a range of alcohols efficiently, with turnover numbers (TONs) of up to 10000.
- Dornan, Laura M.,Muldoon, Mark J.
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p. 1428 - 1432
(2015/04/14)
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- N,O-ligated Pd(ii) complexes for catalytic alcohol oxidation
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N,O-ligated Pd(ii) complexes show considerable promise for the oxidation of challenging secondary aliphatic alcohols. The crystal structures of the highly active complexes containing the 8-hydroxyquinoline-2-carboxylic acid (HCA) and 8-hydroxyquinoline-2-sulfonic acid (HSA) ligands have been obtained. The (HSA)Pd(OAc)2 system can effectively oxidise a range of secondary alcohols, including unactivated alcohols, within 4-6 h using loadings of 0.5 mol%, while lower loadings (0.2 mol%) can be employed with extended reaction times. The influence of reaction conditions on catalyst degradation was also examined in these studies.
- Dornan, Laura M.,Clendenning, Grainne M. A.,Pitak, Mateusz B.,Coles, Simon J.,Muldoon, Mark J.
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p. 2526 - 2534
(2014/07/22)
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- Kinetics and mechanism of oxidation of aliphatic secondary alcohols by benzyltrimethylammonium chlorobromate
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Oxidation of several secondary alcohols by benzyltrimethylammonium chlorobromate (BTMACB) in aqueous acetic acid leads to the formation of corresponding ketones. The reaction is first order with respect to BTMACB and the alcohols. The reaction failed to induce the polymerization of acrylonitrile. There is no effect of tetrabutylammonium chloride on the reaction rate. The proposed reactive oxidizing species is chlorobromate ion. The oxidation of benzhydrol-α-d (PhCDOHPh) exhibited a substantial primary kinetic isotope effect (kH/kD = 5.61 at 298 K). The effect of solvent composition indicated that the rate increases with an increase in the polarity of the solvent. The reaction is susceptible to both the polar and steric effects of the substituents. A mechanism involving transfer of a hydride ion in the ratedetermining step has been proposed.
- Sharma, Pradeep K.
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p. 2702 - 2706
(2014/06/09)
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- Catalytic oxidation of alcohol via nickel phosphine complexes with pendant amines
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Nickel complexes were prepared with diphosphine ligands that contain pendant amines, and these complexes catalytically oxidize primary and secondary alcohols to their respective aldehydes and ketones. Kinetic and mechanistic studies of these prospective electrocatalysts were performed to understand what influences the catalytic activity. For the oxidation of diphenylmethanol, the catalytic rates were determined to be dependent on the concentration of both the catalyst and the alcohol and independent of the concentration of base and oxidant. The incorporation of pendant amines to the phosphine ligand results in substantial increases in the rate of alcohol oxidation with more electron-donating substituents on the pendant amine exhibiting the fastest rates. (Chemical Equation Presented).
- Weiss, Charles J.,Das, Parthapratim,Miller, Deanna L.,Helm, Monte L.,Appel, Aaron M.
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p. 2951 - 2958
(2015/02/19)
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- Manganese-catalyzed selective oxidation of aliphatic C-H groups and secondary alcohols to ketones with hydrogen peroxide
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An efficient and simple method for selective oxidation of secondary alcohols and oxidation of alkanes to ketones is reported. An in situ prepared catalyst is employed based on manganese(II) salts, pyridine-2-carboxylic acid, and butanedione, which provides good-to-excellent conversions and yields with high turnover numbers (up to 10 000) with H2O2 as oxidant at ambient temperatures. In substrates bearing multiple alcohol groups, secondary alcohols are converted to ketones selectively and, in general, benzyl C-H oxidation proceeds in preference to aliphatic C-H oxidation. Manganeasy! MnII, picolinic acid, and butanedione make a smart mix for oxidation of secondary alcohols and alkanes and especially benzylic groups to ketones at room temperature with near stoichiometric amounts of hydrogen peroxide, low catalyst loadings, and high turn-over numbers. Copyright
- Dong, Jia Jia,Unjaroen, Duenpen,Mecozzi, Francesco,Harvey, Emma C.,Saisaha, Pattama,Pijper, Dirk,De Boer, Johannes W.,Alsters, Paul,Feringa, Ben L.,Browne, Wesley R.
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p. 1774 - 1778
(2013/10/21)
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- Synthesis of sterically hindered ketones from aldehydes via O-silyl oximes
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A mild and efficient method to synthesize sterically hindered ketones from aldehydes via O-silyl oximes was developed. Treatment of O-triphenylsilylated oximes with alkyl iodides in the presence of triethyl borane afforded the corresponding ketones.
- Kim, Joong-Gon,Mishra, Mithilesh Kumar,Jang, Doo Ok
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experimental part
p. 3527 - 3529
(2012/08/29)
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- Structure-reactivity relationship for alcohol oxidations via hydride transfer to a carbocationic oxidizing agent
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Second-order rate constants were determined for the oxidation of 27 alcohols (R1R2CHOH) by a carbocationic oxidizing agent, 9-phenylxanthylium ion, in acetontrile at 60°C. Alcohols include open-chain alkyl, cycloalkyl, and unsaturated alcohols. Kinetic isotope effects for the reaction of 1-phenylethanol were determined at three H/D positions of the alcohol (KIEα-D=3.9, KIEβ-D3=1.03, KIE OD=1.10). These KIE results are consistent with those we previously reported for the 2-propanol reaction, suggesting that these reactions follow a hydride-proton sequential transfer mechanism that involves a rate-limiting formation of the α-hydroxy carbocation intermediate. Structure-reactivity relationship for alcohol oxidations was deeply discussed on the basis of the observed structural effects on the formation of the carbocationic transition state (Cδ+-OH). Efficiencies of alcohol oxidations are largely dependent upon the alcohol structures. Steric hindrance effect and ring strain relief effect win over the electronic effect in determining the rates of the oxidations of open-chain alkyl and cycloalkyl alcohols. Unhindered secondary alkyl alcohols would be selectively oxidized in the presence of primary and hindered secondary alkyl alcohols. Strained C7-C11 cycloalkyl alcohols react faster than cyclohexyl alcohol, whereas the strained C5 and C12 alcohols react slower. Aromatic alcohols would be efficiently and selectively oxidized in the presence of aliphatic alcohols of comparable steric requirements. This structure-reactivity relationship for alcohol oxidations via hydride-transfer mechanism is hoped to provide a useful guidance for the selective oxidation of certain alcohol functional groups in organic synthesis. Copyright
- Lu, Yun,Bradshaw, Joshua,Zhao, Yu,Kuester, William,Kabotso, Daniel
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p. 1172 - 1178
(2013/01/12)
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- N-bromo-(4-methylphenyl) sulfonimide: A mild and efficient reagent for oxidative deoximation of oximes under microwave irradiations
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Aldoximes and ketoximes are converted to the parent carbonyl compounds in good yields when treated with N-bromo-(4-methylphenyl) sulfonimide (2), under microwave irradiations. The simple work-up minimizes the loss of product and oximes have been selectively oxidized in the presence of alcohols and alkenes.
- Manesh, Abbas Amini,Khazaei, Ardeshir
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experimental part
p. 624 - 626
(2012/01/03)
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- A convenient method for deoximation of oximes by using N-iodosuccinimide under microwave irradiation
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A rapid and selective method for the cleavage of oximes has been achieved by a simple reaction of a ketoxime or an aldoxime with N-iodosuccinimide in acetone under microwave irradiations.
- Manesh, Abbas Amini,Khazaei, Ardeshir
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experimental part
p. 762 - 764
(2011/12/16)
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- H2O2-oxidation of alcohols promoted by polymeric phosphotungstate catalysts
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A novel polymeric phosphotungstate catalyst bearing a poly(ethylene oxide-pyridinium) matrix was developed that efficiently promoted oxidation of a variety of alcohols, including highly sterically demanding neopentyl alcohols, with hydrogen peroxide, to afford the corresponding carbonyl compounds in up to quantitative yield. The chemoselective oxidation of sterically hindered secondary alcohols in the presence of primary alcohols was achieved. The catalyst could be reused four times without any loss of catalytic activity.
- Yamada, Yoichi M.A.,Jin, Chung Keun,Uozumi, Yasuhiro
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supporting information; experimental part
p. 4540 - 4543
(2010/12/25)
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- Oxidation of secondary alkanols with the system cerium ammonium nitrate-lithium bromide into ketones, α-bromo ketones, and α,α -dibromo ketones
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Oxidation of secondary alkanols with the system Ce(NH4) 2(NO3)6-LiBr in aqueous acetonitrile gave ketones, α-bromo ketones, or α,α-dibromo ketones. The selectivity of the reaction under standard conditions depends only on the molar ratio of the reagents (alkanol : CeIV : LiBr).
- Nikishin,Sokova,Kapustina
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experimental part
p. 391 - 395
(2011/02/17)
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- Oxidation of primary and secondary alkanols with the CeIII-LiBr- H2O2 system
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Action of a novel oxidation system, Ce(NO3)3? 6H2O (cat.)-LiBr (cat.)-H2O2 (stoichiometric oxidant) on primary aliphatic C6-C9 alcohols gives selectively esters, whereas secondary aliphatic C5-C9 alcohols are converted into ketones. Selectivity of these transformations is provided by slow addition of H2O2 to the other reactants.
- Kapustina,Sokova,Nikishin
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experimental part
p. 1284 - 1288
(2011/02/23)
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- Bromodimethylsulfonium bromide (BDMS) in ionic liquid: a mild and efficient catalyst for Beckmann rearrangement
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Bromodimethylsulfonium bromide (BDMS)-catalyzed Beckmann rearrangement of a variety of ketoximes has been carried out in the imidazolium-based ionic liquid [bmim]PF6 under mild conditions without using any additional cocatalyst or solvent to afford excellent conversion and selectivity. The ionic liquid is recovered and reused for up to three runs without any loss of efficiency.
- Yadav, Lal Dhar S.,Garima,Srivastava, Vishnu P.
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scheme or table
p. 739 - 743
(2010/04/05)
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- Catalytic synthesis of oxygenate from alcohol
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The present invention discloses a method for catalytic synthesis of oxygenate from alcohol. At first, a feeding material comprising at least one alcohol is provided. Next, a copper-containing catalyst is provided and the catalyst further comprises at least one metal element selected from the group consisting of the following: zinc, magnesium, and aluminum elements. Following that, a catalytic reaction of the feeding material over the copper-containing catalyst is carried out to synthesize at least one oxygenate.
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Page/Page column 4-8
(2008/06/13)
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- Catalyst and process for the preparation of unsymmetrical ketones
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Carboxylic acid mixtures form unsymmetrical ketones in yields approaching statistical using zirconia catalysts promoted with Group IA and IIA elements. Active catalysts exist in their monoclinic or tetragonal but not cubic form. And the level of promoter loading is generally less than ten percent. The advantages of this catalyst over other ketonization catalysts include its high selectivity to ketones, its low formation of dehydrogenated byproducts, and its stability. The catalyst stability permits its regeneration to remove carbon accumulations by air oxidation. This regeneration restores full catalytic activity.
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Page/Page column 7
(2008/06/13)
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- CATALYST FOR THE PRODUCTION OF METHYL ISOPROPYL KETONE
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A catalyst for the production of methyl isopropyl ketone containing aluminum and titanium oxides, treated with Group 1 or 2 metal hydroxides, or their salts.
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Page/Page column 9-10
(2008/06/13)
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- Catalyst for the preparation of ketones from carboxylic acids
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A catalyst for the preparation of ketones from carboxylic acids is described. The catalyst comprises a mixture of zirconium dioxide, titanium dioxide, and one or more metal oxides from Group 1 or 2 of the Periodic Table of Elements. The catalyst can operate at a lower temperature, reduce coke formation, and provide longer lifetime.
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Page/Page column 3-4
(2008/06/13)
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- N,N′-Dichlorobis(2,4,6-trichlorophenyl)urea (CC-2): An efficient reagent for conversion of oximes to ketones
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A method for the rapid conversion of oximes into the corresponding carbonyl compounds using N,N′-dichlorobis (2,4,6-trichlorophenyl)urea (CC-2) at room temperature is described. The method is economical as the solid by-product bis(2,4,6-trichlorophenyl)urea could be removed by filtration and recycled after re-chlorination.
- Gupta, Arvind K.,Acharya, Jyotiranjan,Pardasani, Deepak,Dubey, Devendra K.
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p. 411 - 414
(2008/02/12)
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- Selective method for the conversion of oximes to their corresponding carbonyl compounds under microwave irradiation by N-bromo-N-phenylpara- toluenesulfonamide
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In this work, oximes are converted to their corresponding carbonyl compounds in good yields using N-bromo-N-phenyl-para-toluenesulfonamide, under microwave irradiation. The simple work-up procedure minimizes loss of product.
- Khazaei, Ardeshir,Sadri, Minoo,Hosseini, Hassan
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p. 1011 - 1015
(2008/02/13)
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- Selective oxidation of oximes to carbonyl compounds using N-bromo-N-benzoyl-4-toluenesulfonamide
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Oximes were converted to parent carbonyl compounds in good yields by treating with N-bromo-N-benzoyl-4-toluenesulfonamide.
- Khazaei, Ardeshir,Manesh, Abbas Amini
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p. 109 - 111
(2007/10/03)
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- Kinetics and mechanism of oxidation of secondary alcohols by benzyltriethylammonium chlorochromate
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Oxidation of several aliphatic secondary alcohols by benzyltriethylammonium chlorochromate in dimethylsulfoxide leads to the formation of corresponding ketones. The reaction is first order each in benzyltriethylammonium chlorochromate and the alcohols. The reaction is catalysed by hydrogen ions. Hydrogen-ion dependence has the form: kobs = a + b [H+]. The oxidation of benzhydrol-α-d exhibits a substantial primary kinetic isotope effect (kH/kD = 6.12 at 288 K). Oxidation of 2-propanol has been studied in nineteen different organic solvents. The solvent effect has been analysed using Taft's and Swain's multiparametric equations. The reaction has been subjected to both polar and steric effects of the substituents. A mechanism involving transfer of hydride ion from alcohol to the oxidant via a chromate ester is also proposed.
- Kaur, Ravdeep,Soni, Neelam,Sharma, Vinita
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p. 2441 - 2445
(2007/10/03)
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- Efficient and selective Al-catalyzed alcohol oxidation via oppenauer chemistry
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A highly active and selective Al-based catalytic Oppenauer (O) oxidation is reported. Quantitative and selective oxidations of a variety of benzylic, propargylic, allylic, and aliphatic primary and secondary alcohols were achieved using nitrobenzaldehyde derivatives as the oxidant and simple aluminum compounds as precatalysts. Copyright
- Graves, Christopher R.,Zeng, Bi-Shun,Nguyen, SonBinh T.
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p. 12596 - 12597
(2008/02/03)
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- Synthetic scope of alcohol transfer dehydrogenation catalyzed by Cu/Al 2O3: A new metallic catalyst with unusual selectivity
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A method for the anaerobic oxidation of a wide series of alcohols including cyclohexanols and steroidal alcohols, has been set up. It relies on a transfer dehydrogenation reaction from the substrate alcohol to styrene catalyzed by a heterogeneous, reusable copper catalyst under very mild liquid phase experimental conditions (90°C, N2) and shows unusual selectivity. Thus, the method is selective for the oxidation of secondary and allylic alcohols even in the presence of unprotected primary and benzylic alcohols. Electronic effects and the choice of the hydrogen acceptor account for the selectivity observed.
- Zaccheria, Federica,Ravasio, Nicoletta,Psaro, Rinaldo,Fusi, Achille
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p. 6426 - 6431
(2008/09/20)
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- Catalytic ketonisation over oxide catalysts. Part XI*. Cross-ketonisation of esters of aliphatic and aromatic acids
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The cross-ketonisation of a mixture of ethyl acetate and ethyl benzoate under flow conditions has been studied over 20wt%MO2/Al 2O3 (M = Mn, Ce or Zr) catalysts, at 673-723 K. High conversions of aromatic ester up to 98% and moderate yields of acetophenone (2/Al2O3 catalyst was the least selective. In its presence, the yield of styrene (34%) exceeded that of acetophenone (31%). Unexpectedly, pure Al2O3 support exhibited the highest selectivity and moderate activity, at 723 K the yield as high as 51% of acetophenone was noted. The transformations of mixtures of various ethyl alkanoates with ethyl benzoate over alumina have been studied. In the case of straight-chain aliphatic esters, the yields of the corresponding 1-phenyl-1-alkanones were in the range of 41-51%. The presence of a methyl group in the α position of the ester (isobutyrate) reduced the yield of ketone strongly (11%); two methyl groups (pivalate) completely inhibited the reaction. The reactivity of a series of alkyl acetates was also studied in the cross-ketonisation reaction with ethyl benzoate over alumina. It has been found that secondary and tertiary alkyl acetates were slightly more selective than their primary counterparts due to the absence of products of transesterification. For these esters at 723 K the yields of acetophenone were in the range of 64-67%. The cross-ketonisation of a mixture of ethyl acetate with substituted ethyl benzoates led to the corresponding derivatives of acetophenone. It has been found that the position of the substituent in the benzene ring plays a crucial role in the reactivity of the ester and determines the extent of yield of the product. The highest yield of ketone (62%) was observed at 723 K for 3-methylacetophenone. 2-Methylacetophenone was formed with low yields (10%) in the whole range of reaction temperatures, probably due to steric effect in the ortho position. At 698 K the maximum yield of 4-methylacetophenone (27%) was attained. The ketonisation of ethyl acetate with ethyl esters of 4-t-butyl- and 4-chlorobenzoic acids led to moderate yields (24-27%) of 4-t-butyl- and 4-chloroacetophenone, respectively.
- Glinski,Koscik,Jerzak,Synoradzki
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p. 995 - 1001
(2007/10/03)
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- Microwave-assisted chemoselective cleavage of oximes to their corresponding carbonyl compounds using 1,3-dichloro-5,5-dimethylhydantoin (DCDMH) as a new deoximating reagent
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In the presence of alkene and alcohol, oximes are converted into their parent carbonyl compounds in good yields when treated with 1,3-dichloro-5,5- dimethylhydantoin (DCDMH) (1), under microwave irradiation. The simple work-up minimizes loss of products. Georg Thieme Verlag Stuttgart.
- Khazaei, Ardeshir,Manesh, Abbas Amini
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p. 1929 - 1931
(2007/10/03)
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- 1,3-Dichloro-5,5-dimethylhydantoin (DCDMH) as a new oxidizing agent for the facile and selective oxidation of oximes to their carbonyl compounds
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Oximes are converted to the parent carbonyl compounds in good yields when treated with 1,3-dichloro-5,5-dimethylhydantoin (DCDMH) (1). An optimized procedure has been developed; the simple work-up minimizes loss of product and oximes have been selectively oxidized in the presence of alcohols and alkenes.
- Khazaei, Ardeshir,Manesh, Abbas Amini
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p. 1017 - 1020
(2007/10/03)
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- Anaerobic oxidation of non-activated secondary alcohols over Cu/Al 2O3
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A liquid phase, transfer dehydrogenation reaction promoted by an 8% Cu/Al2O3 catalyst allows complete conversion of secondary alcohols into ketones under very mild conditions and in short times without any additives.
- Zaccheria, Federica,Ravasio, Nicoletta,Psaro, Rinaldo,Fusi, Achille
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p. 253 - 255
(2007/10/03)
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- Microwave-promoted selective regeneration of carbonyl compounds from oximes using N-bromosaccharin
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N-bromosaccharin was found to be an efficient reagent for the oxidative cleavage of oximes to the corresponding aldehydes and ketones under microwave irradiation in a domestic microwave oven.
- Khazaei, Ardeshir,Manesh, Abbas Amini
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p. 1739 - 1740
(2007/10/03)
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- A new application of N-bromosaccharin as a selective and efficient oxidative reagent for regeneration of carbonyl compounds from oximes
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A new method for the direct conversion of various oximes into aldehydes and, ketones by treatment with N-bromosaccharin is described. N-bromosaccharin can be used for an effective, selective and mild oxidizing agent for the regeneration of carbonyl compounds from oximes in good yield.
- Khazaei, Ardeshir,Manesh, Abbas Amini,Rostami, Amin
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p. 2483 - 2486
(2007/10/03)
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- Facile and chemoselective microwave-assisted cleavage of oximes to their corresponding carbonyl compounds using N,N′-dibromo-N,N′-1,3- propylene-bis[(4-methylphenyl)sulfonamide] as a deoximating reagent
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Aldoximes and ketoximes are converted to the parent carbonyl compounds in good yields when treated with N,N′-dibromo-N,N′-1,3-propylene- bis[(4-methylphenyl)sulfonamide] (2) under microwave irradiation. The simple workup minimizes the loss of product and oximes have been selectively oxidized in the presence of alcohols and alkenes.
- Khazaei, Ardeshir,Manesh, Abbas Amini,Ghasemi, Amir Hoshang
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p. 2784 - 2786
(2007/10/03)
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- A mild and selective method for the conversion of oximes into ketones and aldehydes by the use of N-bromophthalimide
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N-Bromophthalimide has been found to be an efficient and selective reagent for the mild oxidative cleavage of oximes to yield their corresponding carbonyl compounds in good to excellent yields.
- Khazaei, Ardeshir,Manesh, Abbas Amini,Rostami, Amin
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p. 695 - 696
(2007/10/03)
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- Method for preparing ketones by pyrogenic reaction of aldehydes, alcohols, acids or esters
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The invention concerns a method for preparing ketones of formula (I) wherein A and B are as defined in claim 1, consisting of reacting at a temperature ranging between 250 and 500° C. a compound of formula (II): A—X with a compound of formula (III): B—Y, wherein A, B, X and Y are as defined in claim 1, in a coolant solvent having a boiling point higher than 250 ° C., in the presence of a catalyst comprising at least a chemical compound of an element selected among alkali, alkaline-earth metals, lanthanides, Si, Al, Zn, Cu, Co, Fe, Mo, Mn, Cr, V, T, Zr, U, Rh, Tl, Ag, Cd, Pb, Y, Sc and Th, wherein the element is in divalent state or has a higher valency
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Page/Page column 8-9
(2008/06/13)
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- Kinetics and mechanism of the oxidation of secondary alcohols by tetrabutylammonium tribromide
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Oxidation of several secondary alcohols by tetrabutylammonium tribromide (TBATB) in aqueous acetic acid leads to the formation of corresponding ketones. The reaction is first order with respect to TBATB and the alcohols. The reaction failed to induce polymerization of acrylonitrile. There is no effect of tetrabutylammonium chloride on the reaction rate. The proposed reactive oxidizing species is tribromide ion. The oxidation of benzhydrol-α-d (PhCDOHPh) exhibited a substantial primary kinetic isotope effect (k H/kd = 5.15 at 298 K). The effect of solvent composition indicates that the rate increases with an increase in polarity of the solvent. The reaction is susceptible to both polar and steric effects of the substituents. A mechanism involving transfer of a hydride ion in the rate-determining step has been proposed.
- Gosain, Jaya,Sharma, Pradeep K.
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p. 815 - 818
(2007/10/03)
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- Catalytic oxidation of alcohols with allyl diethyl phosphate and palladium acetate
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Allyl diethyl phosphate (ADP) was found to function as a stoichiometric hydrogen acceptor in a catalytic oxidation reaction of alcohols with Pd(OAc)2. A variety of acyclic primary and secondary alcohols were oxidized in good yields and under mild conditions to the corresponding aldehydes and ketones, in the presence of Na2CO3 or K2CO3. Simple aliphatic primary alcohols yielded esters, exclusively. Polar ligand solvents (DMF, DMSO) were found to accelerate the reaction. Slow, but high yield reactions were encountered in THF and acetonitrile as solvents. The reactivity of several other allyl systems serving as H-acceptors, and several Pd compounds serving as catalysts, in the above oxidation reaction, was evaluated. It has been experimentally demonstrated (H-NMR) that ADP is capable of generating a π-allyl-Pd complex using a Pd(0) complex. Consequently, a catalytic cycle was proposed for the above oxidation reaction.
- Shvo, Youval,Goldman-Lev, Vered
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p. 151 - 156
(2007/10/03)
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- The elusive benzocyclobutenylidene: A combined computational and experimental attempt
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Ab initio and density functional theory calculations predict that benzocyclobutenylidene (1) has a singlet ground state in contrast to the parent phenylcarbene and many other simply substituted arylcarbenes. Calculations also predict that 1 should lie in a relatively deep potential well, while its triplet state is 14.5 kcal mol-1 higher in energy. However, attempts to observe 1 directly by photolysis of two different nitrogenous precursors were not successful. Irradiation of diazobenzocyclobutene (7) (λ > 534 nm or λ > 300 nm) or azibenzocyclobutene (10) (λ > 328 nm) in Ar matrixes at 10 K leads to the formation of the strained cycloalkyne 7-methylenecyclohepta-3,5-dien-1-yne (3). 13C-Labeled 3 was also prepared in a similar manner. There is very good agreement between experimental IR spectra and computationally derived harmonic vibrational frequencies for 3 and [13C]-3 and excellent agreement between observed and calculated isotopic shifts. Prolonged short-wavelength irradiation converts 3 into benzocyclobutadiene (5). Phenylacetylene (6) and benzocyclobutadiene dimer (11) were identified as products arising from flash vacuum pyrolysis of diazirine 10 at 500 °C.
- Nicolaides,Matsushita,Yonezawa,Sawai,Tomioka,Stracener,Hodges,McMahon
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p. 2870 - 2876
(2007/10/03)
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- Trifluoroacetylation of ketone O-vinyloximes
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Ketone oxime O-vinyl ethers having alkyl or phenyl radicals react with trifluoroacetic anhydride in ether in the presence of pyridine, yielding 43-54% of the corresponding ketone oxime O-(trans-4,4,4-trifluoro-3-oxo-1-butenyl) ethers with high stereoselec
- Vasil'tsov,Shmidt,Mikhaleva,Zaitsev,Tarasova,Afonin,Toryashinova,Il'icheva,Trofimov
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p. 334 - 338
(2007/10/03)
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- Synthesis and thermal stability of O-vinylketoximes
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The O-vinylketoximes 2 were synthesized from ketoximes 1 and acetylene in superbase systems in good to excellent yields. Their thermal stability was investigated.
- Trofimov, Boris A.,Al'bina, Mikhaleva I.,Vasil'tsov, Alexander M.,Schmidt, Elena Yu.,Tarasova, Ol'ga A.,Morozova, Ludmila V.,Sobenina, Lubov' N.,Preiss, Thomas,Henkelmann, Jochem
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p. 1125 - 1132
(2007/10/03)
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- Vapor-phase synthesis of symmetric ketone from alcohol over CeO2-Fe2O3 catalysts
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Formation of 3-pentanone via oxidative dimerization of 1-propanol was investigated over CeO2-based solid solution with various metal oxides. An addition of Fe2O3 into CeO2 greatly enhanced the 3-pentanone formation, and both 1-propanol conversion and 3-pentanone selectivity were maximized at Fe content of 20 mol%. It was found that the CeO2-Fe2O3 effectively works as a catalyst for the formation of symmetric ketones such as 3-pentanone, 4-heptanone, 5-nonanone, etc.
- Kamimura, Yoichiro,Sato, Satoshi,Takahashi, Ryoji,Sodesawa, Toshiaki,Fukui, Masahiro
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p. 232 - 233
(2007/10/03)
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- Synthesis of ketone O-allyloximes and O-propargyloximes in KOH-DMSO system
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In reaction of ketone oximes with allyl bromide and propargyl chloride in KOH - DMSO system were obtained in good yield previously unknown ketone O-allyloximes and O-propargyloximes. The reactions are accompanied with minor regeneration of ketones (up to 12%, mainly 1-5%).
- Tarasova,Shmidt,Sinegovskaya,Petrova,Sobenina,Mikhaleva,Brandsma,Trofimov
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p. 1581 - 1586
(2007/10/03)
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- Epoxides produced by the oxidation of olefins with air or oxygen
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Catalysts for the selective epoxidization of olefins with atmospheric oxygen, processes for their preparation and processes for the preparation of epoxides by oxidation of olefins with air or oxygen. Compounds of the formula (1) as catalysts for the selective epoxidization of alkenes in which the indices x, y and z have the following meaning: x is a whole number from 1 to 3, y is a whole number from 1 to 2x+1, y being selected so that the sum of x+z gives a metal oxidation number of +5 (vanadium) or +6 (molybdenum, ruthenium); z is a whole number in the range from 2 to 2x; M is molybdenum, ruthenium or vanadium and L is an N, 0 or S donor ligand. Heterogeneous catalysts for the selective oxidation of olefins in the presence of oxygen, comprising an inorganic or organic support material and compounds of the formula (1), and a process for the selective epoxidization of alkenes of the formula STR1 with atmospheric oxygen in the presence of a catalyst of the formula (1) are also described.
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- Synthesis of 3,3-diisopropyl-4-methoxy-4-(siloxy-2-naphthyl)-1,2- dioxetanes and their F--induced chemiluminescent decomposition
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Six isomeric 3,3-diisopropyl-4-methoxy-4-(siloxy-2-naphthyl)-1,2- dioxetanes (3) were synthesized and their F--induced chemiluminescent decomposition were examined in DMSO. The 'odd/even' relationship in Φ(CL) holds for all the dioxetanes (3). On the other hand, the 'odd/even' relationship in emission half-lives t(1/2) is observed for dioxetanes (3c- 3f) with a trigger on the ring B but not for dioxetanes (3a and 3b) with a trigger on the ring A.
- Watanabe, Nobuko,Kobayashi, Hisako,Azami, Mitsunori,Matsumoto, Masakatsu
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p. 6831 - 6840
(2007/10/03)
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- Synthesis of 3-alkoxy-3-aryl-4,4-diisopropyl-1,2-dioxetanes and their base-induced chemiluminescence
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Low-temperature singlet oxygenation of 1-alkoxy-1-aryl-2,2- diisopropylethylenes (9) gives the corresponding 1,2-dioxetanes (10) in high selectivity. Dioxetanes (10) are thermally stable enough to permit handling at room temperature, though an alkoxy group affects significantly their thermal stability and the order of half-life is MeO > tert- BuO. On treatment with tetrabutylammonium fluoride in DMSO, dioxetanes (10e - 10h) bearing a m-siloxyphenyl decompose rapidly to emit intense blue light with ΦCL > 0.2. For the base-induced decomposition of 10e - 10h, the order of rate of decomposition is MeO EtO i-PrO tert-BuO.
- Watanabe, Nobuko,Suganuma, Hiroyuki,Kobayashi, Hisako,Mutoh, Hiroshi,Katao, Yuriko,Matsumoto, Masakatsu
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p. 4287 - 4298
(2007/10/03)
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- Hydrogen bonding Part 44 1Thermodynamics of complexation of 3,5-dichlorophenol with ketones and ethers in cyclohexane: The badger-Bauer relationship
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Equilibrium constants for 1 : 1 hydrogen bond complexation between 3,5-dichioropheno' (DCP) and 17 ketones and 12 ethers in cyclohexane solution have been obtained by an FTIR method that takes into account both diiaerization of the acid and formation of 2 :1 complexes. Enthalpies of complexation for the same ketones and ethers have been determined by a calorimeiric method, leading to values of log K, AG, AH and AS0 for 1 :1 complexation in the 29 systems, as well as log K2 for the 2 :1 complexation between 2 mol of acid and 1 mol of base. For the ketone systems there is very little variation in the three thermodynamic parameters with alkyl substitution, but for the ethers there are systematic variations depending on the alkyl substituent or if the ethers are cyclic. Values of the OH stretching frequency in the DCP complexes with the ketones and ethers in cyclohexane have been obtained. The band shapes for the DCP-ketone complexes are very asymmetric, possibly due to the presence of stereoisomeric complexes, but the VOH band for DCP-ether complexes is symmetric and very suitable for the evaluation of any relationship between v()H and A/f. It is found that for the complexation of DCP with the 12 aliphatic ethers in cyclohexane, there is almost no connection between the calorimetrically determined AH° values and values of AvOH.
- Abraham, Michael H.,Prior, David V.,Schulz, Ronald A.,Morris, Jeffrey J.,Taylor, Peter J.
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p. 879 - 885
(2007/10/03)
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