Names | |||
---|---|---|---|
Preferred IUPAC name Trifluoroacetic acid | |||
Other names 2,2,2-Trifluoroacetic acid 2,2,2-Trifluoroethanoic acid Perfluoroacetic acid Trifluoroethanoic acid TFA | |||
Identifiers | |||
3D model (JSmol) | |||
742035 | |||
ChEBI | |||
ChEMBL | |||
ChemSpider | |||
ECHA InfoCard | 100.000.846 | ||
2729 | |||
PubChem CID | |||
RTECS number |
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UNII | |||
CompTox Dashboard (EPA) | |||
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Properties | |||
C2HF3O2 | |||
Molar mass | 114.023 g·mol−1 | ||
Appearance | colorless liquid | ||
Odor | Pungent/Vinegar | ||
Density | 1.489 g/cm3, 20 °C | ||
Melting point | −15.4 °C (4.3 °F; 257.8 K) | ||
Boiling point | 72.4 °C (162.3 °F; 345.5 K) | ||
miscible | |||
Vapor pressure | 0.0117 bar (1.17 kPa) at 20 °C [1] | ||
Acidity (pKa) | 0.52 [2] | ||
Conjugate base | trifluoroacetate | ||
-43.3·10−6 cm3/mol | |||
Hazards | |||
Occupational safety and health (OHS/OSH): | |||
Main hazards | Highly corrosive | ||
GHS labelling: | |||
Danger | |||
H314, H332, H412 | |||
P260, P261, P264, P271, P273, P280, P301+P330+P331, P303+P361+P353, P304+P312, P304+P340, P305+P351+P338, P310, P312, P321, P363, P405, P501 | |||
NFPA 704 (fire diamond) | |||
Safety data sheet (SDS) | External MSDS | ||
Related compounds | |||
Related perfluorinated acids | Heptafluorobutyric acid Perfluorooctanoic acid Perfluorononanoic acid | ||
Related compounds | Acetic acid Trichloroacetic acid | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Trifluoroacetic acid (TFA) is an organofluorine compound with the chemical formula CF3CO2H. It is a haloacetic acid, with all three of the acetyl group's hydrogen atoms replaced by fluorine atoms. It is a colorless liquid with a vinegar-like odor. TFA is a stronger acid than acetic acid, having an acid ionisation constant, Ka, that is approximately 34,000 times higher, [3] as the highly electronegative fluorine atoms and consequent electron-withdrawing nature of the trifluoromethyl group weakens the oxygen-hydrogen bond (allowing for greater acidity) and stabilises the anionic conjugate base. TFA is widely used in organic chemistry for various purposes.
TFA is prepared industrially by the electrofluorination of acetyl chloride or acetic anhydride, followed by hydrolysis of the resulting trifluoroacetyl fluoride: [4]
Where desired, this compound may be dried by addition of trifluoroacetic anhydride. [5]
An older route to TFA proceeds via the oxidation of 1,1,1-trifluoro-2,3,3-trichloropropene with potassium permanganate. The trifluorotrichloropropene can be prepared by Swarts fluorination of hexachloropropene. [6]
TFA is the precursor to many other fluorinated compounds such as trifluoroacetic anhydride, trifluoroperacetic acid, and 2,2,2-trifluoroethanol. [4] It is a reagent used in organic synthesis because of a combination of convenient properties: volatility, solubility in organic solvents, and its strength as an acid. [7] TFA is also less oxidizing than sulfuric acid but more readily available in anhydrous form than many other acids. One complication to its use is that TFA forms an azeotrope with water (b. p. 105 °C).
TFA is popularly used as a strong acid to remove protecting groups such as Boc used in organic chemistry and peptide synthesis. [8] [9]
At a low concentration, TFA is used as an ion pairing agent in liquid chromatography (HPLC) of organic compounds, particularly peptides and small proteins. TFA is a versatile solvent for NMR spectroscopy (for materials stable in acid). It is also used as a calibrant in mass spectrometry. [10]
TFA is used to produce trifluoroacetate salts. [11]
Trifluoroacetic acid is a corrosive strong acid [12] but it does not pose the hazards associated with hydrofluoric acid because the carbon-fluorine bond is not labile. TFA is harmful when inhaled, causes severe skin burns and is toxic for aquatic organisms even at low concentrations.
TFA's reaction with bases and metals, especially light metals, is strongly exothermic. The reaction with lithium aluminium hydride (LAH) results in an explosion. [13]
TFA is a metabolic breakdown product of the volatile anaesthetic agent halothane. It is thought to be responsible for halothane induced hepatitis. [14]
No known natural processes generate trifluoroacetic acid. [15] In the environment, trifluoroacetic acid may be formed by photooxidation of the commonly used refrigerant 1,1,1,2-tetrafluoroethane (R-134a).[ citation needed ] Moreover, it is formed as an atmospheric degradation product of almost all fourth-generation synthetic refrigerants, also called hydrofluoroolefins (HFO), such as 2,3,3,3-tetrafluoropropene.[ citation needed ]
Trifluoroacetic acid degrades very slowly in the environment, and has been found in increasing amounts as a contaminant in water, soil, food, and the human body. [16] Median concentrations of a few micrograms per liter have been found in beer and tea. [17] Sea water contains about 200 ng of TFA per liter. [18] [19] [20] No biodegradation mechanism for the compound is known in water, [21] although biotransformation apparently decarboxylates the acid to fluoroform. [22]
Trifluoroacetic acid is mildly phytotoxic. [23]
In organic chemistry, an acyl chloride is an organic compound with the functional group −C(=O)Cl. Their formula is usually written R−COCl, where R is a side chain. They are reactive derivatives of carboxylic acids. A specific example of an acyl chloride is acetyl chloride, CH3COCl. Acyl chlorides are the most important subset of acyl halides.
In organic chemistry, an acyl halide is a chemical compound derived from an oxoacid by replacing a hydroxyl group with a halide group.
In organic chemistry, peptide synthesis is the production of peptides, compounds where multiple amino acids are linked via amide bonds, also known as peptide bonds. Peptides are chemically synthesized by the condensation reaction of the carboxyl group of one amino acid to the amino group of another. Protecting group strategies are usually necessary to prevent undesirable side reactions with the various amino acid side chains. Chemical peptide synthesis most commonly starts at the carboxyl end of the peptide (C-terminus), and proceeds toward the amino-terminus (N-terminus). Protein biosynthesis in living organisms occurs in the opposite direction.
An organic acid anhydride is an acid anhydride that is also an organic compound. An acid anhydride is a compound that has two acyl groups bonded to the same oxygen atom. A common type of organic acid anhydride is a carboxylic anhydride, where the parent acid is a carboxylic acid, the formula of the anhydride being (RC(O))2O. Symmetrical acid anhydrides of this type are named by replacing the word acid in the name of the parent carboxylic acid by the word anhydride. Thus, (CH3CO)2O is called acetic anhydride.Mixed (or unsymmetrical) acid anhydrides, such as acetic formic anhydride (see below), are known, whereby reaction occurs between two different carboxylic acids. Nomenclature of unsymmetrical acid anhydrides list the names of both of the reacted carboxylic acids before the word "anhydride" (for example, the dehydration reaction between benzoic acid and propanoic acid would yield "benzoic propanoic anhydride").
The Pummerer rearrangement is an organic reaction whereby an alkyl sulfoxide rearranges to an α-acyloxy–thioether (monothioacetal-ester) in the presence of acetic anhydride.
In organic chemistry, a carbodiimide is a functional group with the formula RN=C=NR. On Earth they are exclusively synthetic, but in interstellar space the parent compound HN=C=NH has been detected by its maser emissions.
Fluoroform, or trifluoromethane, is the chemical compound with the formula CHF3. It is a hydrofluorocarbon as well as being a part of the haloforms, a class of compounds with the formula CHX3 with C3v symmetry. Fluoroform is used in diverse applications in organic synthesis. It is not an ozone depleter but is a greenhouse gas.
The Robinson–Gabriel synthesis is an organic reaction in which a 2-acylamino-ketone reacts intramolecularly followed by a dehydration to give an oxazole. A cyclodehydrating agent is needed to catalyze the reaction It is named after Sir Robert Robinson and Siegmund Gabriel who described the reaction in 1909 and 1910, respectively.
Di-tert-butyl dicarbonate is a reagent widely used in organic synthesis. Since this compound can be regarded formally as the acid anhydride derived from a tert-butoxycarbonyl (Boc) group, it is commonly referred to as Boc anhydride. This pyrocarbonate reacts with amines to give N-tert-butoxycarbonyl or so-called Boc derivatives. These carbamate derivatives do not behave as amines, which allows certain subsequent transformations to occur that would be incompatible with the amine functional group. The Boc group can later be removed from the amine using moderately strong acids. Thus, Boc serves as a protective group, for instance in solid phase peptide synthesis. Boc-protected amines are unreactive to most bases and nucleophiles, allowing for the use of the fluorenylmethyloxycarbonyl group (Fmoc) as an orthogonal protecting group.
Triflic acid, the short name for trifluoromethanesulfonic acid, TFMS, TFSA, HOTf or TfOH, is a sulfonic acid with the chemical formula CF3SO3H. It is one of the strongest known acids. Triflic acid is mainly used in research as a catalyst for esterification. It is a hygroscopic, colorless, slightly viscous liquid and is soluble in polar solvents.
The tert-butyloxycarbonyl protecting group or tert-butoxycarbonyl protecting group is a protecting group used in organic synthesis.
Trifluoroacetic anhydride (TFAA) is the acid anhydride of trifluoroacetic acid. It is the perfluorinated derivative of acetic anhydride.
Acetic acid, systematically named ethanoic acid, is an acidic, colourless liquid and organic compound with the chemical formula CH3COOH. Vinegar is at least 4% acetic acid by volume, making acetic acid the main component of vinegar apart from water. It has been used, as a component of vinegar, throughout history from at least the third century BC.
1-Tetralone is a bicyclic aromatic hydrocarbon and a ketone. In terms of its structure, it can also be regarded as benzo-fused cyclohexanone. It is a colorless oil with a faint odor. It is used as starting material for agricultural and pharmaceutical agents. The carbon skeleton of 1-tetralone is found in natural products such as Aristelegone A (4,7-dimethyl-6-methoxy-1-tetralone) from the family of Aristolochiaceae used in traditional Chinese medicine.
The Boekelheide reaction is a rearrangement of α-picoline-N-oxides to hydroxymethylpyridines. It is named after Virgil Boekelheide who first reported it in 1954. Originally the reaction was carried out using acetic anhydride, which typically required a period at reflux (~140 °C). The reaction can be performed using trifluoroacetic anhydride (TFAA), which often allows for a room temperature reaction.
N-Hydroxyphthalimide is the organic compound with the formula C6H4(CO)2NOH. A white or yellow solid, it is a derivative of phthalimide. The compound is as a catalyst in the synthesis of other organic compounds. It is soluble in water and organic solvents such as acetic acid, ethyl acetate and acetonitrile.
Trifluoroperacetic acid is an organofluorine compound, the peroxy acid analog of trifluoroacetic acid, with the condensed structural formula CF
3COOOH. It is a strong oxidizing agent for organic oxidation reactions, such as in Baeyer–Villiger oxidations of ketones. It is the most reactive of the organic peroxy acids, allowing it to successfully oxidise relatively unreactive alkenes to epoxides where other peroxy acids are ineffective. It can also oxidise the chalcogens in some functional groups, such as by transforming selenoethers to selones. It is a potentially explosive material and is not commercially available, but it can be quickly prepared as needed. Its use as a laboratory reagent was pioneered and developed by William D. Emmons.
(Diacetoxyiodo)benzene, also known as phenyliodine(III) diacetate (PIDA) is a hypervalent iodine chemical with the formula C
6H
5I(OCOCH
3)
2. It is used as an oxidizing agent in organic chemistry.
Sodium trifluoroacetate is a chemical compound with a formula of CF3CO2Na. It is the sodium salt of trifluoroacetic acid. It is used as a source of trifluoromethylations.
Ethyl trifluoroacetate is a chemical compound from the trifluoroacetate group.