- SYNTHESIS AND CRYSTAL STRUCTURE OF 1,1,1,5,5,5-HEXAFLUORO-2-AMINOPENTAN-4-ONE (HFAP)
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The vapour phase reaction of ammonia and hexafluoroacetylacetone leads to the formation of the new β-keto-amine C5H3F6NO.Crystals of the compound are monoclinic, space group P21/n, a = 10.01(2), b = 19.33(3), c = 8.40(1) Angstroem, β = 82.27(6) deg; final R = 0.044.
- Johnson, D.A.,Waugh, A.B.,Hambley, T.W.,Taylor, J.C.
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- One electron transfer chain decomposition of trifluoroacetone diperoxide: The first 1,2,4,5-tetroxane with O-transfer capability
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Reaction of 1,1,1-trifluoropropanone (trifluoroacetone) (1a) with 30% hydrogen peroxide in the presence of conc. sulfuric acid afforded in good yield 3,6-bis(trifluoromethyl)-3,6-dimethyl-1,2,4,5-tetroxane or trifluoroacetone diperoxide (2a). Peroxide 2a is quantitatively converted into trifluoroacetone (1a) and dioxygen by a catalytic amount of tetrabutylammonium iodide through a reductive electron transfer chain reaction carried out by the superoxide ion. Trifluoroacetone diperoxide (2a) is capable of O-atom transfer to alkenes and sulfides.
- Adam, Waldemar,Asensio, Gregorio,Curci, Ruggero,Marco, J. Alberto,Gonzalez-Nunez, Maria Elena,Mello, Rossella
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- Homogeneous liquid-liquid extraction of neodymium(iii) by choline hexafluoroacetylacetonate in the ionic liquid choline bis(trifluoromethylsulfonyl)imide
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The ionic liquid choline bis(trifluoromethylsulfonyl)imide, [Chol][Tf 2N], was used for the extraction of neodymium(iii), in combination with choline hexafluoroacetylacetonate, [Chol][hfac], as the extractant. The binary mixture of [Chol][Tf2N] and water shows temperature-dependent phase behavior, with an upper critical solution temperature of 72 °C. A novel extraction technique, homogeneous liquid-liquid extraction (HLLE), was applied to this solvent system. HLLE is based on the use of thermomorphic solvent mixtures and has the advantage of forming a homogeneous phase during mixing. Extraction is not kinetically hindered by an interface and the extraction equilibrium is reached faster than in the case of heterogeneous mixing in conventional solvent extraction. Several extraction parameters were studied for the extraction of neodymium(iii) with [Chol][hfac]: temperature, pH, extractant concentration and loading of the ionic liquid phase. A speciation study was performed to determine the stoichiometry of the extracted neodymium(iii) complex and a plausible extraction mechanism is proposed. Neodymium is extracted as a tetrakis hexafluoroacetylacetonate complex with one choline cation as counter ion. The crystal structure of the extracted complex showed the presence of a coordination bond between the choline counter ion and the neodymium(iii) center, resulting in a coordination number of nine. The stripping of the loaded neodymium and the influence of acid and extractant concentrations on the phase behavior of the [Chol][Tf2N]-H 2O system were investigated. This journal is the Partner Organisations 2014.
- Onghena, Bieke,Jacobs, Jeroen,Van Meervelt, Luc,Binnemans, Koen
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- One-electron reduction of methyl(trifluoromethyl)dioxirane by iodide ion. Evidence for an electron-transfer chain reaction mediated by the superoxide ion
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One-electron-transfer processes, triggered by I- in catalytic amounts, convert methyl(trifluoromethyl)dioxirane (1) into 1,1,1-trifluoropropanone (trifluoroacetone) and dioxygen. It is proposed that the initially formed bis(oxy)methylene radical anion 1′ performs nucleophilic attack at the dioxirane 1, yielding a dimeric radical anion 2′; the latter then fragments into trifluoroacetone and superoxide ion (O2?-). The intermediacy of Superoxide ion (the propagator of the electron-transfer chain reaction) is demonstrated by its trapping with either benzoyl chloride or chlorotrimethylsilane. Also, potassium superoxide in catalytic amounts induces the fast and complete conversion of 1 into trifluoroacetone with evolution of dioxygen. The redox reaction between dioxirane 1 and iodide ion in acidic medium yields substantial amounts of hydrogen peroxide, which was detected by the catalase probe.
- Adam, Waldemar,Asensio, Gregorio,Curci, Ruggero,González-Nú?ez, Maria Elena,Mello, Rossella
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- Eliminations from 2H-Heptafluorobut-2-ene
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Various approaches are described for dehydrofluorination of heptafluorobut-2-ene (2) to give hexafluorobut-2-yne (1). Molecular sieve is particularly successful. Reaction of (2) with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) surprisingly gave the novel heterocycle (8) via initial nucleophilic attack. Reactions of (2) with other bases are also described.
- Chambers, Richard D.,Roche, Alex J.
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- METHOD FOR OXIDATIVE CLEAVAGE OF COMPOUNDS WITH UNSATURATED DOUBLE BOND
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A method for oxidative cleavage of a compound with an unsaturated double bond is provided. The method comprises the following step: (A) providing a compound (I) with an unsaturated double bond, a reagent with trifluoromethyl, and a catalyst; wherein the catalyst is represented by the following formula (II): M(O)mL1yL2z (II); wherein, M, L1, L2, m, y, z, R1, R2 and R3 are defined in the specification; and (B) mixing the compound with an unsaturated double bond and the reagent with a trifluoromethyl to perform an oxidation of the compound with the unsaturated double bond by using the catalyst at air or an oxygen condition to get a compound presented as formula (III):
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Paragraph 0053-0054; 0060-0061
(2021/03/19)
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- Method for oxidative cracking of compound containing unsaturated double bonds
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The invention relates to a method for oxidative cracking of a compound containing unsaturated double bonds. The method comprises the following steps: (A) providing a compound (I) containing unsaturated double bonds, a trifluoromethyl-containing reagent and a catalyst, wherein the catalyst is shown as a formula (II): M(O)mL1yL2z (II), M, L1, L2, m, y, z, R1, R2 and R3 being defined in the specification; and (B) mixing the compound containing the unsaturated double bonds and the trifluoromethyl-containing reagent, and performing an oxidative cracking reaction on the compound containing the unsaturated double bonds in the presence of air or oxygen by using the catalyst to obtain a compound represented by formula (III),.
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Paragraph 0108-0114; 0121-0126
(2021/07/09)
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- METHOD FOR OXIDATIVE CLEAVAGE OF COMPOUNDS WITH UNSATURATED DOUBLE BOND
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A method for oxidative cleavage of a compound with an unsaturated double bond is provided. The method includes the steps of: (A) providing a compound (I) with an unsaturated double bond, a trifluoromethyl-containing reagent, and a catalyst; wherein, the catalyst is represented by Formula (II): M(O)mL1yL2z??(II);wherein, M, L1, L2, m, y, z, R1, R2 and R3 are defined in the specification; and(B) mixing the compound with an unsaturated double bond and the trifluoromethyl-containing reagent to perform an oxidative cleavage of the compound with the unsaturated double bond by using the catalyst in air or under oxygen atmosphere condition to obtain a compound represented by Formula (III):
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Paragraph 0071; 0076
(2021/07/10)
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- METHODS FOR FUNCTIONALIZATION HYDROCARBONS
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In one aspect, the disclosure relates to a method for functionalizing hydrocarbons. In a further aspect, the method involves heating a hydrocarbon with a composition having an acid and an oxidant. In other aspects, the composition can further include an iodine-based compound and/or a compound having formula AaXn. In any of these aspects, the oxidant can be regenerated in situ or in a separate regeneration step. Also disclosed are functionalized hydrocarbons produced by the disclosed method. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present disclosure.
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Paragraph 0158-0160; 0167-0178; 0199; 02002
(2020/09/27)
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- Catalytic conversion of ketones to esters: Via C(O)-C bond cleavage under transition-metal free conditions
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The catalytic conversion of ketones to esters via C(O)-C bond cleavage under transition-metal free conditions is reported. This catalytic process proceeds under solvent-free conditions and offers an easy operational procedure, broad substrate scope with excellent selectivity, and reaction scalability. This journal is
- Subaramanian, Murugan,Ramar, Palmurukan M.,Rana, Jagannath,Gupta, Virendra Kumar,Balaraman, Ekambaram
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supporting information
p. 8143 - 8146
(2020/09/09)
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- Preparation method of 1,1,1-trifluoroacetone
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The invention discloses a preparation method of 1,1,1-trifluoroacetone. According to the method, a methyl magnesium halide Grignard reagent and trifluoroacetate are taken as raw materials, a Grignardreaction occurs in an ether solvent, and then the 1,1,1-trifluoroacetone is obtained through acidification and direct distillation. The preparation method of the 1,1,1-trifluoroacetone has the advantages that the raw materials are easy to obtain, the post-treatment purification is convenient, the operation is simple, the cost is relatively lower, the yield is high, and the product purity is high;the prepared 1,1,1-trifluoroacetone is an important trifluoromethyl synthetic building block and is an important organic intermediate for synthesizing many fluorine-containing drugs, pesticides and polymeric materials.
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Paragraph 0014-0020
(2019/07/08)
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- Method for increasing recovery rate of trifluoroacetone
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The invention provides a method for increasing a recovery rate of 1, 1, 1-trifluoroacetone. The method comprises the following steps: firstly, fully mixing 1, 1, 1-trifluoroacetone tail gas with an organic solvent; and then, performing rectification operation to obtain a product. The method provided by the invention can efficiently separate 1, 1, 1-trifluoroacetone from ethylene and carbon dioxide in the tail gas, and has the characteristics of high recovery rate of 1, 1, 1-trifluoroacetone, low energy consumption and less equipment investment.
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Paragraph 0032; 0033
(2017/10/25)
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- Preparative synthesis of 2,2-dimethyl-5-(trifluoroacetyl)-1,3-dioxane-4,6-dione (2-trifluoroacetyl Meldrum's acid) and 2,2-dimethyl-6-(trifluoromethyl)-4H-1,3-dioxin-4-one and their synthetic usefulness as (trifluoroacetyl)ketene precursors
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A simple and reliable method for the preparation of 2,2-dimethyl-5-(trifluoroacetyl)-1,3-dioxane-4,6-dione and 2,2-dimethyl-6-(trifluoromethyl)-4H-1,3-dioxin-4-one on a multigram scale was developed. These (trifluoroacetyl)ketene precursors were used in the hetero-Diels-Alder reaction with dialkylcyanamides and 1-ethoxyprop-1-yne, as well as in some reactions with nucleophiles.
- Sevenard, Dmitri V.,Didenko, Andrey V.,Lorenz, Denis,Vorobiev, Michael,Stelten, Johannes,Dülcks, Thomas,Sosnovskikh, Vyacheslav Ya.
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supporting information
p. 1495 - 1502
(2017/02/18)
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- Preparation of fluorine-containing methyl or aryl alkyl ketone method
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The invention discloses a method for preparing fluorine-containing methyl or alkylaryl ketones, belonging to an organic synthesis field. The method comprises two steps of: ester condensation: ester condensation reaction of an R1COOR2 compound represented by a formula A with a R2COOR2 compound represented by a formula B, is performed to form an R1COCH(R3)COOR2 intermediate represented by a formula C; and ester interchange: R1COCH(R3)COOR2 represented by the formula C is carried out ester interchange reaction with R2COOH under 100-110 DEG C and with catalysis of dilute H2SO4 or a cationic resin, and then decarboxylating to obtain R1COR2 fluorine-containing methyl or alkylaryl ketones represented by a formula D. The R1 group may be CF3-, CF2-, CF- or Ar-; the R2 group may be CH3-, Et- and n-Pr; and the R3 group may be CH3-, Et- and H-. Ester interchange in the invention avoids formation of HOR2 which has a nearly same boiling point with the compound represented by the formula D and is azeotropic with the compound represented by the formula D, enables the compound represented by the formula D to be purified without series rectification operation, and is suitable for large scale production. Simultaneously, ester interchange in the invention greatly raises cost. An ion exchange resin completes ester interchange in a waterless condition, which avoids a de-watering step, and simplifies technologies.
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Paragraph 0077
(2016/10/07)
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- Economical and practical strategies for synthesis of α-trifluoromethylated amines
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A powerful approach to synthesize α-trifluoromethylated amines has been developed. The method is operationally simple, broad in substrate scope and amenable to scale-up using trifluoroacetic anhydride. Meanwhile, the strategy not only provided a versatile approach to synthesize α-trifluoromethylated amines but also provides a new method for exploring the new reactivity of trifluoroacetic anhydride.
- Jiang,Cheng,Yuan
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p. 2406 - 2408
(2016/05/19)
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- Chemoenzymatic dynamic kinetic resolution of α-trifluoromethylated amines: Influence of substitutions on the reversed stereoselectivity
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Enzymatic resolution of α-trifluoromethylated amines via kinetic resolution (KR), dynamic kinetic resolution (DKR) employing CALB-Pd/Al 2O3, and a one-pot sequential process of KR/DKR/KR was investigated comparatively for the first time. Although CALB-catalyzed KR of α-trifluoromethylated amines with substituents of methyl (1a), isopropyl (1c), phenyl (1d) and benzyl group (1e) can provide good stereoselectivity factors E from 31 to >200 respectively, DKR and sequential process of KR/DKR/KR possess better practical application potential because of the higher conversion (62%-84%) and the similar enantiomeric excesses (90%-99%). The enantiopreference and inversion for the α-trifluoromethylated amines displayed by CALB were observed and explained by docking modes. Namely, for 1,1,1-trifluoro-2-propylamine (1a), the product amide with R-configuration was obtained, and the enantiopreference was converted to S for the amines (1b-1e) with substituents larger than methyl group. The catalysts recycle, and scale-up experiments were demonstrated successfully. All these results indicated the high efficiency and green feature of this enzymatic process, and its application significance.
- Cheng, Guilin,Xia, Bo,Wu, Qi,Lin, Xianfu
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p. 9820 - 9828
(2013/09/02)
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- Catalytic asymmetric hydrogenation of α-CF3- or β-CF3-Substituted acrylic acids using Rhodium(I) complexes with a combination of chiral and achiral ligands
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Only the mixture works! Acrylic acid derivatives with CF3 substituents in α or β position were efficiently hydrogenated in the presence of a RhI complex with a chiral secondary phosphine oxide (SPO; see scheme) and an achiral Ph3P as ligands. The corresponding propanoic acid derivatives were obtained with generally high conversion (>99 %) and high enantioselectivity (92->99 %). Copyright
- Dong, Kaiwu,Li, Yang,Wang, Zheng,Ding, Kuiling
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supporting information
p. 14191 - 14195
(2014/01/06)
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- The nascent OH detection in photodissociation of 2-(bromomethyl)hexafluoro- 2-propanol at 193 nm: Laser-induced fluorescence study
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Photodissociation of 2-(bromomethyl)hexafluoro-2-propanol (BMHFP) and 3-bromo-1-propanol (BP), involving σC-BrnBr transition at 193 nm, has been investigated by measuring laser-induced fluorescence spectra of the expected OH product. The OH channel is a minor dissociation pathway with a quantum yield of 0.17 ± 0.05 in BMHFP, whereas it was not observed in BP. Partitioning of the available energy into translation, rotation, and vibration of the photoproducts has been measured by state selective detection of the nascent OH product in BMHFP. OH is produced mostly in the ground vibrational level (v″ = 0), with a rotational distribution being characterized by a temperature of 465 ± 25 K. But, a significant fraction of the available energy of 30.2 kcal mol-1 is partitioned into translation of OH (14.6 kcal mol-1). The OH(v″ = 0, J″) populations in the spin-orbit states as well as in the Λ-doublet states are statistical. A plausible mechanism of OH formation on excitation of BMHFP at 193 nm is suggested, with the primary reaction channel being elimination of Br atom by direct C-Br bond dissociation from a repulsive surface. The Br radical is detected using (2 + 1) resonance-enhanced multiphoton ionization (REMPI) at ~234 nm. It is produced in both the ground (2P3/2) and the excited (2P1/2) spin-orbit states with the relative quantum yield of the latter to be 0.36. The co-fragment of Br undergoes secondary C-O bond dissociation to produce OH and F3C-C(CH 2)-CF3, with the reaction having a barrier located in the exit channel. In this two-step three-body dissociation process, a major fraction of the available energy is released into translation (〈fT〉 ~ 0.75), resulting from an impulsive C-Br bond dissociation in the primary step and presence of an exit barrier in the secondary process. Experimental results combined with theoretical calculations provide a clear picture of the dynamics of OH formation from BMHFP at 193 nm. In addition, the energetics of another channel, competing with OH, have been calculated from the primary product F3C-C(CH2)(OH)-CF3. In contrast to BMHFP, the OH product could not be observed from the photolysis of 3-bromo-1-propanol (another saturated halogenated propanol) at 193 nm under the detection limit of the present experimental condition, although it has a higher absorption cross-section at 193 nm.
- Indulkar, Yogesh N.,Upadhyaya, Hari P.,Kumar, Awadhesh,Waghmode, Suresh B.,Naik, Prakash D.
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experimental part
p. 210 - 219
(2012/07/14)
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- Process for the preparation of (S) - or (R) -3,3,3-trifluoro-2-hydroxy-2-methylpropionic acid
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The present invention relates to a novel process for the preparation of (S)- or (R)-3,3,3-trifluoro-2-hydroxy-2-methylpropionic acid and to novel microorganisms capable of utilizing the propionamide of the formula in the form of the racemate or of its optically active isomers as the sole nitrogen source.
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- PURIFICATION OF 1,1,1,3,3,3-HEXAFLUOROISOPROPANOL
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1,1,1,3,3,3-Hexafluoroisopropanol (HFIP) substantially free of 1,1,1-trifluoroacetone (TFA) can be separated from a mixture containing both compounds by A) catalytic reduction with hydrogen followed by fractional distillation; B) cooling to a temperature at which HFIP freezes and TFA remains liquid; C) forming a high boiling complex comprising HF and TFA followed by fractional distillation; or D) producing HF-free conditions to yield a HFIP/TFA azeotrope followed by fractional distillation. It is emphasized that this abstract is provided to comply with the rules requiring an abstract, which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 CFR § 1.72(b).
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Page/Page column 1
(2008/06/13)
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- Process for producing 1,1,1-trifluoroacetone
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The invention relates to a process for producing 1,1,1-trifluoroacetone, which is useful as an intermediate of pharmaceuticals and agricultural chemicals, or as a reagent for introducing fluorine-containing groups. This process includes the step of conducting a hydrogenolysis of a halogenated trifluoroacetone, which is represented by the formula [1], by a hydrogen gas, in a liquid phase containing water, in the presence of a catalyst containing a transition metal, where X represents a chlorine, bromine or iodine, and n represents an integer from 1 to 3. It is possible by the process to easily produce 1,1,1-trifluoroacetone with high purity.
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- Method for preparing fluorinated ketones
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A subject of the present invention is a process for preparation of fluorinated ketones corresponding to general formula (I) R1—CO—R2 in which R1 and R2 are as defined in claim 1, characterized in that it consists of reacting two carboxylic acids of Formula (II), R1—COOH and Formula (III), R2—COOH, in the gaseous phase and in the presence of a catalyst comprising at least one oxide of an element chosen from the rare earths, thorium, titanium and aluminium.
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- Process for producing 1,1,1-trifluoroacetone
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A process for producing 1,1,1-trifluoroacetone includes the step of conducting a hydrogenolysis of a halogenated trifluoroacetone, which is represented by the general formula (1), by a hydrogen gas in the presence of a catalyst containing a transition metal, where X represents a chlorine, bromine or iodine, and n represents an integer from 1 to 3. It is possible to obtain 1,1,1-trifluoroacetone with a high yield by using the special catalyst.
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- Selection, purification, characterisation, and cloning of a novel heat-stable stereo-specific amidase from Klebsiella oxytoca, and its application in the synthesis of enantiomerically pure (R)- and (S)-3,3,3-trifluoro-2-hydroxy-2-methylpropionic acids and (S)-3,3,3-trifluoro-2-hydroxy-2-methylpropionamide
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We isolated, characterised, and cloned an enantio-specific amidase from Klebsiella oxytoca and used it to resolve (R,S)-3,3,3-trifluoro-2-hydroxy-2-methylpropionamide, giving (R)3,3,3-trifluoro-2-hydroxy-2-methylpropionic acid and (S)-3,3,3-trifluoro-2-hydroxy-2-methylpropionamide. The (S)-amide could then be hydrolysed chemically to (S)-3,3,3-trifluoro-2-hydroxy-2-methylpropionic acid. The process can therefore be adapted to produce both (R)-and (S)-enantiomers of 3,3,3-trifluoro-2-hydroxy-2-methylpropionic acid, or (S)-3,3,3-trifluoro-2-hydroxy-2-methylpropionamide. The biocatalytic step is part of a combined chemical and biocatalytic route that starts from ethyl trifluoroacetoacetate. The products typically have a purity of greater than 98% and ee values of essentially 100% after isolation. The process has been used to produce 100-g amounts of the (S)-acid, and successfully scaled up to produce 100-kg amounts of the (R)-acid, with the biotransformation carried out at the 1500-L scale.
- Shaw, Nicholas M.,Brieden, Walter,De Riedmatten, Patricia,Roduit, Jean-Paul,Zimmermann, Bertin,Neumueller, Roman,Naughton, Andrew,Robins, Karen,Tinschert, Andreas,Schmid, Evelyne,Hischier, Marie-Louise,Venetz, Veronika,Werlen, Josef,Zimmermann, Thomas
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p. 497 - 504
(2013/09/06)
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- Process for producing 1,1,1-trifluoroacetone
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The invention relates to a process for producing 1,1,1-trifluoroacetone. This process includes reacting a halogenated acetone with a metal in the presence of a proton donor. This halogenated acetone is represented by the general formula (1): where X represents a chlorine atom, bromine atom or iodine atom, and n represents an integer from 1 to 3. It is possible to easily obtain 1,1,1-trifluoracetone from the halogenated acetone, which is easily available.
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- Cesium fluoride catalyzed trifluoromethylation of esters, aldehydes, and ketones with (trifluoromethyl)trimethylsilane
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The low reactivity of carboxylic esters toward (trifluoromethyl)trimethylsilane (TMS-CF3) was investigated. A universal cesium fluoride catalyzed procedure for nucleophilic trifluoromethylation was developed. At room temperature (25 °C, with catalytic amounts of cesium fluoride, carboxylic esters were found to react to give the silyl ether intermediates, which afforded the trifluoromethyl ketones after hydrolysis. Sulfonic, sulfinic, and selenic esters also show good reactivity, giving novel trifluoromethylated compounds. The trifluoromethylation method was also applied to aldehydes and ketones, which were transformed to trifluoromethyl silyl ether intermediates and afforded trifluoromethylated alcohols in excellent yields after acid hydrolysis. Ethylene glycol dimethyl ether was used as solvent for solid or high boiling substrates, and benzonitrile was used for the low boiling substrates.
- Singh, Rajendra P.,Cao, Ganfeng,Kirchmeier, Robert L.,Shreeve, Jean'ne M.
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p. 2873 - 2876
(2007/10/03)
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- The oxidation of secondary alcohols by potassium tetraoxoferrate(VI)
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The kinetics of the oxidation of 2-propanol, 1,1,1-trifluoro-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 1-phenyl-2,2,2-trifluoroethanol, 1-(4-methylphenyl)-2,2,2-trifluoroethanol, 1-(3-bromophenyl)-2,2,2-trifluoroethanol, and 1-(3-nitrophenyl)-2,2,2-trifluoroethanol by potassium tetraoxoferrate(VI) have been studied under basic conditions. The products are ketones, formed in almost quantitative yields, iron(III) hydroxide, and dioxygen. The reactions are characterized by substantial enthalpies of activation (40-60 kJ/mol), very unfavorable entropies of activation, large primary deuterium isotope effects, and a positive Hammett p value. Both acid and base catalysis are observed. Acid catalysis is attributed to formation of a more reactive oxidant, HFeO4-, at low pH. Base catalysis is attributed partly to the conversion of the reductants to alkoxide ions at high pH, and partly to the reaction of hydroxide ion with tetraoxoferrate(VI) to give a five-coordinated species, HOFeO43-, that reacts rapidly with nucleophiles. A reaction mechanism involving formation of an intermediate ferrate ester is proposed.
- Norcross, Bruce E.,Lewis, William C.,Gai, Huiffa,Noureldin, Nazih A.,Lee, Donald G.
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p. 129 - 139
(2007/10/03)
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- Process for preparation of ketones
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A process for preparing ketones, for example CF3 C(O)CH3, CF3 C(O)CH2 C(O)CF3 and CF3 C(O)CF2 H, in which β-ketoesters are transesterified and decarboxylated using a carboxylic acid, for example trifluoroacetic acid, in the presence of a catalyst, particularly an onium salt of a carboxylic acid or an effective amount of a proton-donating acid, preferably a sulfonic acid such as alkyl- or arylsulfonic acids, or a mineral acid. The process is advantageously carried out in the absence of water, so that no formation of acetals or hydrates occurs, and no dehydrating step is needed. The process is simple to carry out, and if transesterification is carried out with a sufficiently active carboxylic acid, for example with trifluoroacetic acid, the presence of an additional catalyst is unnecessary.
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- 2H-Heptafluorobut-2-ene as a synthon for hexafluorobut-2-yne
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Reactions of heptafluorobut-2-ene with nucleophiles are described, in some cases giving products analogous to those previously obtained from hexafluorobut-2-yne. Depending on the conditions, hydrolysis can lead to 1,1,1,4,4,4-hexafluorobutan-2-one, or 1,1,1-trifluoroacetone. Reactions with diols, bis-phenols, ammonia and amines are also described.
- Chambers, Richard D.,Roche, Alex J.
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p. 139 - 143
(2007/10/03)
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- Para-hydroxyalkylation of hydroxylated aromatic compounds
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Hydroxylated aromatic compounds devoid of substituents in the para-position to the hydroxyl group thereof are para-hydroxyalkylated, e.g., into optionally substituted p-hydroxymandelic acid compounds, more particularly p-hydroxymandelic acid and 3-methoxy-p-hydroxymandelic acid, by condensing same with an organic carbonyl compound in the presence of a quaternary ammonium hydroxide.
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- KINETIC RELATIONS IN THE THERMODECOMPOSITION OF CALCIUM AND STRONTIUM F-SUBSTITUTED β-DIKETONATES
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Kinetic relations in the thermodecomposition of calcium and strontium substituted β-diketonates (acetylacetonates, trifluoroacetylacetonates, pivaloyltrifluoroacetylacetonates, dipivaloylmethanates) and their volatilities were studied by the manometric technique under static conditions.
- Tsyganova, E. I.,Titova, O. M.,Faerman, V. I.,Stepanova, L. V.,Aleksandrov, Yu. A.
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p. 195 - 198
(2007/10/02)
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- Process for perfluoroalkylation of acid anhydrides
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A process for the preparation of perfluoroalkylated ketones and/or perfluoroalkylated alcohols, comprising the step of contacting a perfluoroalkyl iodide or perfluoroalkyl bromide with an acid anhydride, in the presence of a metal chosen from zinc and cadmium.
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- Ionic Probes of Aromaticity in Annelated Rings
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Ionization by the deprotonation of benzene and pyridine, and by the protonation of pyridine, involves lone pairs in the ? plane without significant ? effects.In these cases annelation by a benzene ring increases the acidity or proton affinity by a constant 6+/-1 kcal/mol, ascribed to increased polarizability.In comparison, protonation of benzene and deprotonation of cyclopentadiene disrupts or creates a 6-electron aromatic system, respectively, and in their annelated derivatives, naphthalene and indene, a secondary 4-electron conjugated ? system.These cases involving ? electrons show annelation effects that are substantially larger (13.4 kcal/mol) or smaller (1.0 kcal/mol), respectively, than just the electrostatic effect.Analysis of these data suggests that the stability of secondary 4-electron system in the annelated rings is smaller by 6+/-1 kcal/mol than the aromatic 6-electron systems, in fair agreement with Herndon's structure-resonance values for these species.Annelation effects are reproduced well by Dewar's AM1 semiempirical method.
- Meot-Ner (Mautner), Michael,Liebman, Joel F.,Kafafi, Sherif A.
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p. 5937 - 5941
(2007/10/02)
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- Models for Strong Interactions in Proteins and Enzymes. 1. Enhanced Acidities of Principal Biological Hydrogen Donors
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The acid dissociation energies of several key biological hydrogen donors are found to fall into a narrow range, ΔHoacid=352-355 kcal/mol.The strong acidities of these donor groups enhance the hydrogen bond strengths involved in the protein α-helix, imidazole enzyme centers and DNA.Specifically, the peptide link is modeled by the dipeptide analogue CH3CO-Ala-OCH3.Its acidity is strengthened, i.e. ΔHoacid is decreased by 8 kcal/mol compared with other amides, due to electrostatic stabilization by the second carbonyl in the peptide -CON-CH(CH3)CO- grouping.The acidity of imidazole is also strengthened by 8 kcal/mol compared with that of the parent molecule, pyrrole, primarily due to resonance stabilization of the ion.Hydrogen donor NH2 groups of adenine and cytosine are modeled by 4-aminopyrimidine, and the acidity of this amine group is strengthened by ring aza substitution.An intrinsic acidity optimized for hydrogen bonding strength therefore emerges as a common property of the diverse hydrogen donors in the protein α-helix, enzymes and DNA.This property may therefore be in part responsible for the natural selection of these molecules as principal biological hydrogen donors.
- Meot-Ner (Mautner), Michael
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p. 3071 - 3075
(2007/10/02)
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- CH3(.) vs. CF3(.): Relative Rates of Formation from β-Scission
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The relative rates of formation of CH3(.) and CF3(.) from β-scission reactions of trifluoro-t-butoxy radical (1) have been measured to be about 10:1 by thermolysing both trifluoro-t-butyl hypochlorite (4) and bis(trifluoro-t-butyl) peroxydicarbonate (14) in CCl4 at 160 and 140 deg C.
- Jiang, Xi-Kui,Li, Xing-Ya,Wang, Ke-Yang
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p. 745 - 746
(2007/10/02)
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- Kinetic Study of the Gas-phase Decomposition of the Trifluoroacetyl Radical. Effects of Temperature and Pressure upon the Rate Constants
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The kinetics and pressure dependence of the decomposition of the trifluoroacetyl radical: CF3CO+M->CF3+CO+M (5') have been studied by generating the radicals from the selective photolysis of azomethane in the presence of 1,1,1-trifluoroacetaldehyde over the temperature range 338-417 K.The rate constants of the decomposition reaction (k5') have been measured relative to the radical combination reactions: CH3+CF3CO->CF3COCH3 (6) 2CH3->C2H6 (2).The rate constants (k5'), were found to be pressure-dependent over the pressure range 50-740 Torr, with SF6 as a bath gas.The A factor of the radical decomposition reaction has been calculated from transition-state theory to be A5' ca. 2.2E13 s-1.Treatment of the pressure dependence of the rate constants (k5'), according to the RRKM theory of unimolecular reactions, yielded a high-pressure limiting activation energy E5'=83.1 kJ mol-1.Thus the present data consistent with a high-pressure limiting Arrhenius expression: log(k5'/s-1)=(13.34+/-0.8)- where the error limits are estimates of the accuracies of the Arrhenius parameters.The results are discussed in relation to existing data on the CF3CO radical and are compared with kinetic data on the decomposition reactions of the CH3CO and C2H5CO radicals.
- Kerr, J. Alistair,Wright, J. Paul
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p. 1471 - 1482
(2007/10/02)
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- Reaction Products of 2-Aminobenzenethiol with some β-Diketones
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2-Aminobenzenethiol undergoes condensation reactions with several β-diketones (CH3, CF3 and C6H5 substituents) to form benzothiazolines.Conversion to benzothiazines and benzothiazoles occurs in some instances, as documented by isolation and spectroscopic characterization of the products.
- Alyea, Elmer C.,Malek, Abdul
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p. 1325 - 1327
(2007/10/02)
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- Kinetics of the Gas-Phase Addition Reaction of Methyl Radicals to Hexafluoroacetone: An Extension of the Temperature Range
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By pyrolysing azomethane over the temperature range 583 to 624 K in the presence of hexafluoroacetone the kinetics of the addition reaction, CH3(.) + (CF3)2CO --> (CF3)2C(O)CH3(.) (1) have been studied.Rate constants (k1) have been measured and in conjunction with previous data, from the pyrolysis of di-t-butyl peroxide in the presence of hexafluoroacetone over the temperature range 405 to 450 K, the combined Arrhenius equation, corresponding to the temperature range 405 to 624 K, is given by k1/dm3mol-1s-1 = (4.0 +/- 1.4) x 1E7exp(-(2290 +/- 160)/T); relative to the value k3 = 2.2 x 1E10 dm3mol-1s-1 for the reaction 2CH3(.) --> C2H6 (3).The revised Arrhenius parameters, A1 = (4.0 +/- 1.4) x 1E7 dm3mol-1s-1 and E1 = 19.0 +/- 1.3 kJ mol-1 should be considerably more accurate than our original data.
- Drew, Roger M.,Kerr, J. Alistair
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p. 2343 - 2351
(2007/10/02)
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- Kinetics of the Thermal Gas-phase Decomposition of 2,3-Epoxy-1,1,1-trifluoropropane
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In the temperature range 677-741 K, 2,3-epoxy-1,1,1-trifluoropropane decomposes at ca. 100 Torr initial pressure by a unimolecular mechanism, to give initially 1,1,1-trifluoropropanone and 3,3,3-trifluoropropanal as the only major products.Rate constants for formation of these products were determined in the presence of 8 percent nitric oxide to reduce the importance of secondary reactions.At 100 Torr the reactions are close to their unimolecular high pressure limits and (equations).Comparison of this reaction with the decomposition of 2,3-epoxypropane shows that substitutuion of CF3 for CH3 on the oxiran ring apparently strengthens the C-O bond adjacent to the substituent but has little effect on the C-O bond opposite the substituent.
- Flowers, Michael C.,Honeyman, Malcolm R.
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p. 2290 - 2295
(2007/10/02)
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- REACTIVITY OF ORGANOTIN COMPOUNDS. XX. ACYLDEMETALLATION OF RSnMe3 compounds
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The reactions of RSnMe3 with R=CH3 (I), C4H9 (II), C6H5 (III), 9-fluorenyl (IV), 9-methyl-9-fluorenyl (V), indenyl (VI), and C6H5CC (VII) with acetyl chloride (VIII), benzoyl chloride (IX), and trifluoroacetic anhydride (X) in methylene chloride at room temperature, leading to the formation of unsymmetrical ketones, were investigated.It was shown that the reactions of (I-III) with (VIII-X) and also of (VII) with (VIII) and (IX) only occur in the presence of aluminium chloride, whereas a catalyst is not required for the reactions of (VI) and (VII) with (X).Compounds(IV-VI) react with (VIII) and (IX) only in presence of Et4NCl or Bu4NBr, and this is explained by the participation of ion pairs R-+Sn(CH3)3, formed by coordination of the halide ion at the tin atom and possessing higher nucleophilicity than the covalent form RSn(CH3)3.The formation of 8-methyl-8-acetoxybenzofulvene in the reaction of (VI) with (VIII) shows that metallation of the strong CH acid 1-acetylindene by the action of compound (VI) occurs in the presence of a nucleophilic catalyst (Et4NCl).
- Kashin, A. N.,Bumagin, N. A.,Kalinovskii, I. O.,Beletskaya, I. P.,Reutov, O. A.
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p. 1329 - 1334
(2007/10/02)
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