Nov 07, 2015 with rare synn asymmetrically carboxylatebridged diironii complexes 12 in hand, we sought to understand their solution dynamics by applying nmr spectroscopy. When nmethyl5phenyl1,2,3,6tetrahydropyridine 230 is arylated under the same conditions, 3,3diphenylpiperidine 232 is formed. The 31p nmr spectrum of the hydrogen addition product, 4, indicates that a mixture of isomers is present, but the positions. Citations are the number of other articles citing this article, calculated by crossref and updated daily. The reaction products are analyzed as a mixture of isomers because the triflate derivatives are quite unstable and cannot be separated into individual isomers by chromatography. The subsequent product is then deprotonated, usually to reestablish an aromatic system. Characterization of 5 was by multinuclear nmr spectroscopy. Nmr spectroscopy of fluorine19 presentation by zakiaafzal phd student 20 2. Standardizing for 19f nmr my current project has me making a bunch of complexes with fluorinated ligands. The triflation reaction is very fast up to 3 equivalents of the acid added it had been completed before the first spectrum was taken.
Does anyone have a published protocol for obtaining the anhydrous acid from the anhydride. Electrochemical fluorination and radiofluorination of. Flush victims eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Jun 23, 2017 the complexity in the dissolution of thoria tho2 and thoriumbased fuels at an industrial scale is one of the limiting factors for the implementation of the thorium fuel cycle. Triflic acid as efficient catalyst for the hydroamination. A dialkylborenium ion stabilized by an nheterocyclic carbene has been prepared for the first time by reaction of imes9bbnh with triflic acid.
Nuclear magnetic resonance studies of surface interactions. Reacts exothermically with chemical bases examples. Interaction of acetonitrile with trifluoromethanesulfonic. The formylation of toluene in trifluoromethanesulfonic acid. The typical impurity in triflic anhydride is triflic acid, which is also a colorless liquid.
Because of their paramagnetism, however, 1 and 2 are not well suited for such a study. The product was eluted with hexanes to 2% ethyl acetate in. This creates a carbocation which then reacts with a pi system similar to a friedelcrafts reaction. Whennotfois formedin situ byreaction oftfohwith hno3, it mononitrates toluene at 60c and dinitration is nearly quantitative at 0c15. Interaction of acetonitrile with trifluoromethanesulfonic acid. The static 1h and 19f solidstate nmr results show that the addition of htf has no apparent effect on local molecular mobility of the gtf matrix at room temperature. Atet, and subsequently doped with triflic acid ta at. Trifluoromethanesulfonic acid sc203415 hazard alert code key. May 11, 2014 fluorine19 nuclear magnetic resonance fluorine19 nuclear magnetic resonance is an analytical technique used to identify fluorinecontaining compounds.
The parent acid and triflate are versatile reactants and solvents in many organic chemistry. Substitution of the fifth phenyl group was accompanied by ring cleavage. I tried to distill under a slow stream of nitrogen about 10 ml of triflic anhydride yellowbrown solution with about 5 ml of. Do not put any ointments, oils, or medication in the victims eyes without specific instructions from a physician. I require a small amount of triflic acid, and while other research groups do not have any, i did locate some trflic anhydride. A solvent and halogenfree synthesis of high purity triflate ionic liquids via direct alkylation of. Mechanisms for the removal of benzyl protecting groups in synthetic peptides by trifluoromethanesulfonic acid trifluoroacetic acid dimethyl sulfide. The resulting silyl triflates are among the most reactive silylating. Using a traditional textwithfigures format, the article gives an overview of. All structured data from the file and property namespaces is available under the creative commons cc0 license. Because it is difficult to assign absolute configurations to specific isomers. Trifluoroacetic acid was not biodegraded during a yearlong study using laboratory aquatic microcosms and ecosystem sedimentwater systems. Triflic acid promoted decarboxylation of adamantane. The present invention relates to a process for the preparation of a sulfonic acid anhydride and more particularly to the preparation of triflic anhydride.
Triflic anhydride is the chemical compound with the formula cf3so22o. Zhu, haijin, macfarlane, douglas and forsyth, maria 2014, probing ion exchange in the triflic acid guanidinium triflate system. Samples of triflic anhydride can be assayed by 19 f nmr spectroscopy. Evans values 14 for water and 35 for dmso were extrapolated using various methods. Probing ion exchange in the triflic acidguanidinium triflate. Excess amount of triflic acid addition decreasing the yield, quenching with triethyl amine gives a clean reaction mixture if we pour direct it in ice water it will form back colored emulation. This article describes the use of fluorine 19f nmr for the analysis and structure determination of biomaterials. The reaction is believed to proceed by initial formation of a 1,4dication 228, which forms in preference to the 1,3dication 231.
Problem r10h c5h no 300 mhz 1h nmr spectrum in d o source. Repor palii aia4 hiec iii tirre or data laig ac r he. Section 1 chemical product and company identification. Detection of triflic acid monitored at 35 c by 19f nmr in cd2cl2. Spectroscopy amino acids nmr and more ground terms important emission lines in the flame photometry symbols for nmr 1h chemical shifts 11b chemical shifts c chemical shifts 15n chemical shifts 17o chemical shifts 19f chemical shifts 27al chemical shifts 29si chemical shifts 31p chemical shifts important silylated compounds used as 1h shift. Probing ion exchange in the triflic acid guanidinium. Fluorine19 nuclear magnetic resonance fluorine19 nuclear magnetic resonance is an analytical technique used to identify fluorinecontaining compounds. Trifluoromethanesulfonic acid and derivatives chemical. In this study, we investigated the dissolution of unirradiated thoria powder, simulating thoria from nuclear fuel production scrap, in trifluoromethanesulfonic acid triflic acid solutions. The kinetics of the reaction have been studied by 1 h nmr spectroscopy, which reveal that the tfoh acid undergoes a self. After 10 min stirring, the volume was reduced to about 20 ml and the solution was directly loaded onto a column of silica with some bicarbonate mixed in the top sand layer to remove trace acid. This compound is a strong electrophile, useful for introducing the triflyl group, cf 3 so 2. Triflic anhydride is the chemical compound with the formula cf 3 so 2 2 o. Request pdf 19f and1h nmr spectra of halocarbons 19f nmr chemical shifts and coupling constants are reported for 215 compounds.
Fr29043a1 process for the preparation of sulfonic acid. Triflic acid catalyzes the arylation of nmethyl1,2,3,6tetrahydropyridine 227 to give 4phenylpiperidine 229 scheme 59. Packaging 1, 4 kg in glass bottle 50, 250, 500 g in glass bottle 5, 10 g in ampule. The nature of the interaction between trifluoromethanesulfonic acid triflic acid. Samples of triflic anhydride can be assayed by 19f nmr spectroscopy. Probing ion exchange in the triflic acidguanidinium. It is a hygroscopic, colorless, slightly viscous liquid and is soluble in polar solvents. After 10 min stirring, the volume was reduced to about 20 ml and the solution was directly loaded onto a column of. Trifluoroacetic anhydride was reacted with the maminophenoxide terminated ptmo to serve as a fluorine tag, then analyzed using 19p nmr spectroscopy to quantify the amount of hydroxy end groups present if any. Syntheses of methyl and ethyl triflate by the reaction of triflic acid with. Working with hazardous chemicals organic syntheses. It will convert phenols into a triflic ester, which enables cleavage of the co bond. Methyl trifluoromethanesulfonate c2h3f3o3s pubchem. These metrics are regularly updated to reflect usage leading up to the last few days.
Phosphorus31 and fluorine19 nmr spectra were recorded on. Journal of the american chemical society 1986, 108 17, 52425251. Here and further the chemical shifts of acetonitrile are in fact those of its mixture with the protonated form, the nmr signals are averaged due to a rapid exchange. Organic letters bronsted acid catalyzed addition of phenols. Trifluoromethanesulfonic triflic acid is a versatile and. Trifluoromethanesulfonic triflic acid is a versatile and very efficient. Samples are best stored in sealed glass ampules or glass bottles with kel. Repor palii aia4 hiec iii tirre or data laig ac r he n. First check the victim for contact lenses and remove if present.
Two types of propagating species, which were directly observed from the 19fnmr spectra, were found to be oxonium macroions and triflic macroesters. Triflic acid 44 l was added carefully to the solution. Triflic acid owes many of its useful properties to its great thermal and chemical stability. Extreme high moderate low section 1 chemical product and company identification product name trifluoromethanesulfonic acid statement of hazardous nature considered a hazardous substance according to osha 29 cfr 1910. Negative shifts are those that appear upfield of cfcl3 and positive shifts are those that appear downfield. Triflic acid is a known super acid whose conjugate base is a very weak nucleophile. It is the acid anhydride derived from triflic acid. Ill run 19f nmr on the 2 distilled fractions i got. The submitter obtained a colorless solution of boron triflate, but the checkers observed development of a yelloworange color upon addition of triflic acid. Fluorine nmr data fluorine shifts overview reference compounds 19 f shifts. In a reaction with silica gel, the peak intensity at 77. The 19 f nmr spinlattice relaxation time t 1 dependence on temperature suggests that the dominant relaxation mechanism for 19 f is a combination of spinrotation sr interactions, one of which seems to be. Triflate trifluoromethanesulfonate is the conjugate base of triflic acid. Probing ion exchange in the triflic acid guanidinium triflate system.
The nature of the interaction between trifluoromethanesulfonic acid triflic acid and the surface groups of silica as a support has been investigated by 1 h and 19 f nmr studies. In particular, provide an explanation for the appearance of the key multiplet 3. Two types of propagating species, which were directly observed from the 19f nmr spectra, were found to be oxonium macroions and triflic macroesters. A dialkylborenium ion via reaction of nheterocyclic. Supplementary information for triflic acidmediated phenylation of nacylaminoalkyl diethylacetals and nacyl2phenyl cyclic amides frank d. Supplementary information for triflic acidmediated. When contacted with moist in air, it forms a hydrated solid. Are bronsted acids the true promoter of metaltriflatecatalyzed. Abbreviated tf 2 o, triflic anhydride is the acid anhydride of the strong acid triflic acid. Article views are the countercompliant sum of full text article downloads since november 2008 both pdf and html across all institutions and individuals. The ionseparated nature of the borenium ion was confirmed by 1h and 19f diffusion ordered nmr spectroscopy.
Structure, properties, spectra, suppliers and links for. Files are available under licenses specified on their description page. The formylation of toluene in trifluoromethanesulfonic acid was studied in a batch reactor to determine the effect on reaction rate of increasing the ratio of trifluoromethanesulfonic acid. Triflic acid is widely used especially as a catalyst and a precursor in organic chemistry. Dissociation of the protonated diphosphine ligands is a likely mode of decomposition under these strongly acidic conditions. Review of the catalytic application of triflic anhydride, acid and esters to fine chemical and pharmaceutical synthesis.
Widely used reagent for the synthesis of alkyl and vinyl triflates. Supplementary information sample preparation cholinetriflate was made by the neutralization reaction of triflic acid with choline hydroxide. Trifluoromethanesulfonic acid 19f nmr chemical shifts. Triflic acid mediated dealkylative lactonisation via nmr. Triflic acid 5mol% is an efficient catalyst, which firstly applied to the antimarkovnikov intermolecular hydroamination of ethyl acrylate with 2aminopyridines, sharply improves yields as high as 96%, reduces reaction times as short as 12h. Comparison by nitronium salts superacidic and media. Nuclear magnetic resonance studies of surface interactions between. Typically the synthesis involves a drop wise addition of aqueous solution of 1 mole of triflic acid aldrich 5. Triflic acid is used in cyclization reactions either by protonating a multiple bond.
It thus appears safer to add the acid at room temperature, slowly, so that it reacts immediately. How to get anhydrous triflic acid from triflic anhydride. The process for the preparation of a sulfonic acid anhydride according to the invention is characterized by the fact that it comprises reacting a sulfonic acid or a mixture of two sulfonic acids with a reagent having the acid pseudohalide. Supplementary information royal society of chemistry. Nature of hydrogen interactions with niii complexes.
Reacts violently with water to generate hydrofluoric acid and sulfuric acid. Triflic acid 14936 nmr spectrum, triflic acid h nmr spectral analysis, triflic acid c nmr spectral analysis ect. Triflic acid is also very effective because its conjugate base does not act as a nucleophile. Use of triflic acid in the recycling of thoria from nuclear. These reactions can generate dangerously large amounts of heat in small spaces.
Triflic acid is mainly used in research as a catalyst for esterification. Dearylation competes with the exchange of silyl triflates with triflic acid and leads to the thermodynamic. Our modified reaction conditions can tolerate some substrates. Our nmr facilities allow us to be able to do 19f nmr easily enough but id like to be able to standardize my chemical shifts. Contact with cork, rubber, and plasticized materials will cause rapid discoloration of the acid and deterioration of the materials. Trifluoromethanesulfonic triflic acid is a versatile and very efficient dearylating reagent 6,7. Up to four triflate groups could be easily introduced to the ring. Triflic acid addition should not go beyond 5 o c to 0 o c some time decomposition of reaction mixture happening. Nmr spectra were recorded on either a 500 mhz varian inova spectrometer.