406-95-1Relevant articles and documents
Imidazolium salt assisted hydrolysis of 1-chloro-2,2,2-trifluoroethane
Lee, Hyunjoo,Kim, Kyung Hwan,Kim, Honggon,Lee, Sang Deuk,Kim, Hoon Sik
, p. 95 - 98 (2004)
The use of imidazolium-based ionic liquids as promoters was found to be highly effective for the hydrolysis reaction of CF3CH2Cl with aqueous potassium acetate to produce 2,2,2-trifluoroethanol (TFE). Among ionic liquids tested, 1-butyl-3-methylimidazoliu
Automated data evaluation and modelling of simultaneous 19F-1H medium-resolution NMR spectra for online reaction monitoring
Zientek, Nicolai,Laurain, Clment,Meyer, Klas,Paul, Andrea,Engel, Dirk,Guthausen, Gisela,Kraume, Matthias,Maiwald, Michael
, p. 513 - 520 (2016)
Medium-resolution nuclear magnetic resonance spectroscopy (MR-NMR) currently develops to an important analytical tool for both quality control and process monitoring. In contrast to high-resolution online NMR (HR-NMR), MR-NMR can be operated under rough environmental conditions. A continuous re-circulating stream of reaction mixture from the reaction vessel to the NMR spectrometer enables a non-invasive, volume integrating online analysis of reactants and products. Here, we investigate the esterification of 2,2,2-trifluoroethanol with acetic acid to 2,2,2-trifluoroethyl acetate both by 1H HR-NMR (500 MHz) and 1H and 19F MR-NMR (43 MHz) as a model system. The parallel online measurement is realised by splitting the flow, which allows the adjustment of quantitative and independent flow rates, both in the HR-NMR probe as well as in the MR-NMR probe, in addition to a fast bypass line back to the reactor. One of the fundamental acceptance criteria for online MR-MNR spectroscopy is a robust data treatment and evaluation strategy with the potential for automation. The MR-NMR spectra are treated by an automated baseline and phase correction using the minimum entropy method. The evaluation strategies comprise (i) direct integration, (ii) automated line fitting, (iii) indirect hard modelling (IHM) and (iv) partial least squares regression (PLS-R). To assess the potential of these evaluation strategies for MR-NMR, prediction results are compared with the line fitting data derived from the quantitative HR-NMR spectroscopy. Although, superior results are obtained from both IHM and PLS-R for 1H MR-NMR, especially the latter demands for elaborate data pretreatment, whereas IHM models needed no previous alignment.
Preparation and characterization of trifluoroethyl aliphatic carboxylates as co-solvents for the carbonate-based electrolyte of lithium-ion batteries
Lu, Wei,Xie, Kai,Chen, Zhong Xue,Pan, Yi,Zheng, Chun Man
, p. 110 - 119 (2014/05/06)
In this work, a series of trifluoroethyl aliphatic carboxylates with different carbon-chain lengths in acyl group are prepared and investigated as the co-solvents for the carbonate-based electrolyte of lithium-ion batteries. The trifluoroethyl aliphatic carbonates are synthesized by a modified one-step approach, using aliphatic carboxylic acid and trifluoroethanol as the raw materials (molar ratio, 1.2:1), hydrogen ion exchange resin as the catalyst and silica gel drier as the de-hydration. The structure and electrochemical properties of the final products have been characterized by FTIR, 1H NMR, GC-MS, viscosity, conductivity meter and electrochemical measurements. The structure characterizations show that the final products have high purity. Electrochemical tests present that the co-solvents are able to improve the electrochemical performances of graphite electrode at low temperature. In particular, we find that an addition of trifluoroethyl n-hexanoate (TFENH) into 1 M LiPF6/EC + EMC electrolyte can significantly decrease the Li de-intercalation potential of graphite by 540 mV and achieve a high capacity retention of 92% at 218 K. The electrochemical impedance spectroscopy (EIS) measurements indicate that the observed performance improvement at low temperature is associated with the decreased surface film resistance (R SEI) by the addition of co-solvents.
BF3·2CF3CH2OH (BF 3·2TFE), an efficient superacidic catalyst for some organic synthetic transformations
Prakash, G. K. Surya,Mathew, Thomas,Marinez, Eric R.,Esteves, Pierre M.,Rasul, Golam,Olah, George A.
, p. 3952 - 3958 (2007/10/03)
BF3 · 2CF3CH2OH complex was found to be a very effective superacidic catalyst comparable in acid strength to at least that of 100% anhydrous sulfuric acid for various acid-catalyzed organic transformations such as isomerizations, rearrangements, ionic hydrogenation of various ketones, and aromatics with triethylsilane and nitration of aromatics with metal nitrate. Studies of the pivalaldehyde-methyl isopropyl ketone rearrangement and the benzopinacol to phenanthrene transformation suggest that the complex has an acidity comparable to that of 100% anhydrous sulfuric acid. The structure and properties of the 1:2 boron trifluoride-trifluoroethanol complex have been further studied using NMR (1H, 13C, 19F, 11B) and DFT calculations at the B3LYP/6- 311++G**//B3LYP/6-31G* level.
Transition state stabilization by micelles: Thiolysis of p-nitrophenyl alkanoates in cetyltrimethylammonium bromide micelles
Tee,Yazbeck
, p. 1100 - 1108 (2007/10/03)
Thiolysis of p-nitrophenyl esters (acetate to decanoate) by the anion of 2-mercaptoethanol (ME) is catalyzed by micelles of cetyltrimethylammonium bromide (CTAB) in aqueous solution. At fixed [ME], the observed rate constants (k(obs)) show saturation with
SN2 mechanism for alcoholysis, aminolysis, and hydrolysis of acetyl chloride
Bentley, T. William,Llewellyn, Gareth,McAlister, J. Anthony
, p. 7927 - 7932 (2007/10/03)
First-order solvolysis rate constants are reported for solvolyses of acetyl chloride in methanol and MeOD, and in binary aqueous mixtures with acetone, acetonitrile, ethanol, methanol, and trifluoroethanol at 0°C. Product selectivities (S = [MeCOOR]/[MeCOOH] x [water]/[alcohol]) are reported for solvolyses in ethanol/ and methanol/water at 0°C. Solvolyses of acetyl chloride show a high sensitivity to changes in solvent ionizing power, consistent with C-Cl bond cleavage. As the solvent is varied from pure ethanol (or methanol) to water, S values and rate-rate profiles show no evidence for the change in reaction channel observed for solvolyses of benzoyl and trimethylacetyl chlorides. However, using rate ratios in 40% ethanol/water and 97% trifluoroethanol/ water (solvents of similar ionizing power but different nucleophilicities) to compare sensitivities to nucleophilic attack, solvolyses of acetyl chloride are over 20-fold more sensitive to nucleophilic attack than benzoyl chloride. The solvent isotope effect of 1.29 (MeOH/MeOD) for acetyl chloride is similar to that for p-methoxybenzoyl chloride (1.22) and is lower than for benzoyl chloride (1.55). Second-order rate constants for aminolyses of acetyl chloride with m-nitroaniline in methanol at 0°C show that acetyl chloride behaves similarly to p-methoxybenzoyl chloride, whereas benzoyl chloride is 40-fold more sensitive to the added amine. The results indicate mechanistic differences between solvolyses of acetyl and benzoyl chlorides, and an SN2 mechanism is proposed for solvolyses and aminolyses by m-nitroaniline of acetyl chloride (i.e. these reactions are probably not carbonyl additions, but a strong sensitivity to nucleophilic attack accounts for their high rates).
Intramolecular 1,2-alkyl shifts in unsymmetric dialkoxycarbenes studied by very low vapour pressure (VLVP) pyrolysis - mass spectrometry
Suh,Pole,Warkentin,Terlouw
, p. 544 - 548 (2007/10/03)
Methoxy-(2,2,2-trifluoroethoxy)carbene radical cations, CH3O-C-OCH2CF3·+, 1·+, are cleanly generated by the dissociative electron ionization (EI) of 2-methoxy-5,5-dimethyl-2-(2, 2,2-trifluoroethoxy)-Δ3-1,3,4-oxadiazoline I. Neutralization-reionization (NR) mass spectrometry of the neutral carbene 1, generated by one-electron reduction of 1·+, shows no recovery ion signal and thus 1 is not a viable species within the μs time scale of the experiment. Very low vapour pressure (VLVP) pyrolysis - mass spectrometry of I in conjunction with (multiple) collision experiments shows that 1 completely isomerizes, via a 1,2-trifluoroethyl shift, into methyl 3,3,3-trifluoropropionate, CF3CH2C(=O)OCH3, 1a. This technique was also used to study the related dialkoxycarbenes C2H5O-C-OCH2CF3, 2, CH3O-C-OC2H5, 3, and CH3O-C-OCH(CH3)2, 4, generated from the corresponding 2,2-dialkoxy-5,5-dimethyl-Δ3-1,3,4-oxadiazolines. The pyrolytically generated carbene 2 behaves analogously to 1 and completely isomerizes to ethyl 3,3,3-trifluoropropionate, 2a. The neutral carbenes 3 and 4 undergo only a partial isomerization via 1,2-alkyl shifts in which the ethyl and isopropyl groups show a slightly greater migratory aptitude, respectively, than the methyl group. The differences in migratory aptitude are explained in terms of a transition state model similar to that of a 1,2-H shift in carbenes, with development of negative charge in the migrating group. The greater migratory aptitude of CF3CH2, as compared to CH3 and CH3CH2, is attributed to the stabilization of negative charge in the transition state by strongly electron-withdrawing β-fluorines whereas the differences in migratory aptitude between the alkyl groups in 3 and 4 are largely due to the greater polarizability of isopropyl and ethyl groups, as compared to the methyl group.
Acyl Transfer Mediated by Complexation. The Effect of Cyclodextrins on the Reaction of Nucleophiles with p-Nitrophenyl Acetate and Hexanoate
Tee, Oswald S.,Gadosy, Timothy A.
, p. 2307 - 2312 (2007/10/02)
The kinetics of the cleavage of p-nitrophenyl acetate (pNPA) and p-nitrophenyl hexanoate (pNPH) by trifluoroethanol (TFE), mercaptoethanol, hydroxylamine or imidazole in the presence of α-cyclodextrin, β-cyclodextrin, or hydroxypropyl-β-cyclodextrin (CDs)
Preparation and properties of new methyl(alkoxo)- and methyl(thiolato)nickel and methyl(alkoxo)- and methyl(thiolato)palladium complexes. CO and CS2 insertion into the alkoxo-palladium bond
Kim, Yong-Joo,Osakada, Kohtaro,Sugita, Kouji,Yamamoto, Takakazu,Yamamoto, Akio
, p. 2182 - 2188 (2008/10/08)
Reactions of fluorinated alcohols (HOCH(CF3)2, HOCH2CF3, and HOCH(CF3)C6H5) or aromatic thiols (HSC6H5 and HSC6H4-p-CH3) with dialkylnickel and -palladium complexes (NiMe2(bpy), NiEt2(bpy) (bpy = 2,2′-bipyridine), NiMe2(dpe), and PdMe2(dpe) (dpe = 1,2-bis(diphenylphosphino)ethane)) give the corresponding monoalkyl complexes with an alkoxo or a thiolato ligand (NiMe(OR)(bpy), NiEt(OR)(bpy), MMe(OR)(dpe), and MMe(SAr)(dpe) (M = Ni, Pd; R = CH(CF3)2, CH2CF3, CH(CF3)C6H5)). These complexes have been characterized by elemental analysis and NMR (1H, 31P{1H}, 19F, and 13C{1H}) spectroscopy. The methyl(alkoxo)nickel(II) and -palladium(II) complexes thus obtained react with carbon monoxide at normal pressure to give carboxylic esters in high yields. Reaction of carbon monoxide with NiMe(SAr)(dpe) (Ar = C6H5, C6H4-p-CH3) also gives the corresponding carbothioic esters in good yields, while PdMe(SPh)(dpe) is unreactive with carbon monoxide under similar conditions. The 31P{1H} and 13C{1H} NMR spectra of the reaction mixture of PdMe(OCH(CF3)2)(dpe) with an equimolar amount of 13CO at -60°C show the formation of PdMe (13COOCH(CF3)2)(dpe) produced through insertion of the carbon monoxide into the Pd-O bond. When the reaction temperature is raised to -20°C, this alkoxycarbonyl complex undergoes reductive elimination to give 1,1,1,3,3,3-hexafluoro-2-propyl acetate. The reaction is accompanied by simultaneous decarbonylation of the alkoxycarbonyl ligand to regenerate PdMe(OCH(CF3)2)(dpe). The reaction of PdMe(OCH(CF3)Ph)(dpe) with carbon disulfide gives an isolable palladium complex, PdMe(SCSOCH(CF3)Ph)(dpe), formed by insertion of CS2 into the Pd-O bond, while PdMe(SPh)(dpe) is unreactive with CS2.
