Trifluoroacetic Acid and Trifluoroacetic Anhydride Radical Cations Dissociate near the Ionization Limit

2019 ◽  
Vol 123 (29) ◽  
pp. 6313-6318
Author(s):  
Lukas Lesniak ◽  
Juana Salas ◽  
Jake Burner ◽  
Malick Diedhiou ◽  
Maxi A Burgos Paci ◽  
...  
Keyword(s):  
Trifluoroacetic Acid ◽  
Radical Cations ◽  
Trifluoroacetic Anhydride ◽  
Ionization Limit

313. Studies of trifluoroacetic acid. Part V. Trifluoroacetic anhydride as a condensing agent in reactions of nitrous and nitric acids

1952 ◽  
pp. 1695 ◽  
Author(s):  
E. J. Bourne ◽  
M. Stacey ◽  
J. C. Tatlow ◽  
J. M. Tedder
Keyword(s):  
Trifluoroacetic Acid ◽  
Trifluoroacetic Anhydride

N,N-Dialkyl-N′-Chlorosulfonyl Chloroformamidines in Heterocyclic Synthesis. Part XIII. Cleavage and Rearrangement Reactions of Pyrazolo[1,5-b][1,2,4,6]thiatriazine 1,1-Dioxides

2016 ◽  
Vol 69 (1) ◽  
pp. 61 ◽  
Author(s):  
Rebecca E. Norman ◽  
Michael V. Perkins ◽  
Andris J. Liepa ◽  
Craig L. Francis
Keyword(s):  
Ethyl Acetate ◽  
Dimethyl Sulfoxide ◽  
Trifluoroacetic Acid ◽  
Sulfonic Acid ◽  
Trifluoroacetic Anhydride ◽  
Ring Cleavage ◽  
Thermal Rearrangement ◽  
Heterocyclic Synthesis ◽  
Similar Treatment ◽  
Catalytic Hydrogenolysis

Treatment of pyrazolo[1,5-b][1,2,4,6]thiatriazines 1 with the Vilsmeier–Haack reagent afforded pyrazolo[1,5-a][1,3,5]triazines 5. Reaction of compounds 1 with trifluoroacetic anhydride, dimethyl sulfoxide, and triethylamine afforded 5-dimethylsulfanylidene derivatives 8. The guanidino-pyrazole-sulfonic acid 9 was produced from treatment of compounds 1 with trifluoroacetic acid under anhydrous conditions. Similar treatment in the presence of water afforded the desulfonated pyrazolo-guanidine 6. Reactions of 6 with one-carbon electrophiles provided various 4-substituted pyrazolo[1,5-a][1,3,5]triazines 5. Attempted catalytic hydrogenolysis of N7-benzyl pyrazolo[1,5-b][1,2,4,6]thiatriazines 2 in alcohols led to sulfamates 12 from thiatriazine ring cleavage. Ethyl acetate or tert-butanol as solvent allowed successful debenzylation to provide compounds 1. Aminolysis of compounds 2 gave sulfamides 13. Thermal rearrangement of compounds 2 afforded 6-benzyl-pyrazolo[3,4-e][1,2,4]thiadiazines 14.

Clean-Chemistry Sulfonation of Aromatics

2002 ◽  
Vol 2002 (7) ◽  
pp. 326-327 ◽  
Author(s):  
Brian W. Corby ◽  
Anthony D. Gray ◽  
Padraig J. Meaney ◽  
Michael J. Falvey ◽  
Gregory P. Lawrence ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Trifluoroacetic Acid ◽  
Trifluoroacetic Anhydride ◽  
Phase System

A solution of TFAA/H2SO4 is an atom-efficient liquid-phase system for rapid sulfonation of aromatic structures; H2SO4 is consumed stoichiometrically and the spent trifluoroacetic anhydride (TFAA) is readily recovered as trifluoroacetic acid (TFA) which can be recycled to TFAA.

Ipso nitration. XVIII. Nitrationof 2-chloro-1,3,5-trimethylbenzene: nitration ipso to chlorine

1978 ◽  
Vol 56 (10) ◽  
pp. 1348-1357 ◽  
Author(s):  
Alfred Fischer ◽  
Sachdev Singh Seyan
Keyword(s):  
Acetic Acid ◽  
Ambient Temperature ◽  
Trifluoroacetic Acid ◽  
Boron Trifluoride ◽  
Boron Trifluoride Etherate ◽  
Trifluoroacetic Anhydride ◽  
Trans Isomers ◽  
Dimethyl Benzyl ◽  
Cis And Trans Isomers ◽  
Cis And Trans

Nitration of 2-chloro-1,3,5-trimethylbenzene in acetic anhydride gives the cis and trans isomers of 4-chloro-1,3,5-trimethyl-4-nitrocyclohexa-2,5-dienyl acetate (1, 21%), the cis and trans isomers of 3-chloro-2,4,6-trimethyl-4-nitrocyclohexa-2,5-dienyl acetate (2, 6%), and 2-chloro-1,3,5-trimethyl-4-nitrobenzene (73%). Diene 1 reacts with acidified aqueous acetone to form the corresponding dienol, acidified methanol to form the methyl ether, and hydrogen chloride to form the corresponding chloride. In acetic acid a mixture of 4-chloro-3,5-dimethyl-benzyl derivatives and 3-chloro-2,4,6-trimethylphenyl acetate are formed. In trifluoroacetic acid – trifluoroacetic anhydride and also in boron trifluoride etherate, 2-chloro-1,3,5-trimethyl-4-nitrobenzene is the predominant product. Diene 2 on reaction with acetic acid, acidified methanol, trifluoroacetic acid – trifluoroacetic anhydride, and boron trifluoride etherate gives 3-chloro-2,4,6-trimethylphenyl acetate. Some 2-chloro-4-nitromesitylene is obtained in trifluoromethanesulfonic acid. Diene 2 also gives the acetate on standing at ambient temperature or at −20 °C, and on pyrolysis. Diene 1 gives 4-chloro-3,5-dimethylphenylnitromethane on standing at ambient temperature or at −20 °C but a mixture of 2-chloro-1,3,5-trimethyl-4-nitrobenzene, chloromesitylene, and 3-chloro-2,4,6-trimethylphenyl acetate on pyrolysis.

THE NUCLEAR MAGNETIC RESONANCE SPECTRA OF TRIARYL CARBONIUM IONS

1959 ◽  
Vol 37 (9) ◽  
pp. 1402-1408 ◽  
Author(s):  
R. B. Moodie ◽  
T. M. Connor ◽  
Ross Stewart
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Trifluoroacetic Acid ◽  
Chemical Shifts ◽  
Trifluoroacetic Anhydride ◽  
Para Position ◽  
Single Peak ◽  
Carbonium Ions ◽  
Nuclear Magnetic Resonance Spectra ◽  
Neutral Compounds

The N.M.R. spectra of the triphenylmethyl cation and several of its derivatives substituted with methyl, methoxyl, and tert-butyl groups in the meta or para position have been obtained in trifluoroacetic acid – trifluoroacetic anhydride solution. The ring protons and substituent protons are all shifted to lower fields, i.e. are less shielded in the carbonium ions than in the neutral compounds of similar structure. The chemical shifts for the substituent protons are greater for para than for meta substituents and for mono- rather than tri-substituted ions. With each ion only a single peak was observed for the substituent protons but the ring protons were, in some cases, well resolved. The theoretical implications of these results are discussed.

scholarly journals Transparent and Robust All-Cellulose Nanocomposite Packaging Materials Prepared in a Mixture of Trifluoroacetic Acid and Trifluoroacetic Anhydride

Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 368 ◽  
Author(s):  
Susana Guzman-Puyol ◽  
Luca Ceseracciu ◽  
Giacomo Tedeschi ◽  
Sergio Marras ◽  
Alice Scarpellini ◽  
...  
Keyword(s):  
Trifluoroacetic Acid ◽  
Food Packaging ◽  
Cellulose Nanofibers ◽  
Barrier Properties ◽  
Trifluoroacetic Anhydride ◽  
Packaging Films ◽  
Force Microscopy ◽  
Water Barrier ◽  
Cellulose Composites ◽  
Food Packaging Films

All-cellulose composites with a potential application as food packaging films were prepared by dissolving microcrystalline cellulose in a mixture of trifluoroacetic acid and trifluoroacetic anhydride, adding cellulose nanofibers, and evaporating the solvents. First, the effect of the solvents on the morphology, structure, and thermal properties of the nanofibers was evaluated by atomic force microscopy (AFM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA), respectively. An important reduction in the crystallinity was observed. Then, the optical, morphological, mechanical, and water barrier properties of the nanocomposites were determined. In general, the final properties of the composites depended on the nanocellulose content. Thus, although the transparency decreased with the amount of cellulose nanofibers due to increased light scattering, normalized transmittance values were higher than 80% in all the cases. On the other hand, the best mechanical properties were achieved for concentrations of nanofibers between 5 and 9 wt.%. At higher concentrations, the cellulose nanofibers aggregated and/or folded, decreasing the mechanical parameters as confirmed analytically by modeling of the composite Young’s modulus. Finally, regarding the water barrier properties, water uptake was not affected by the presence of cellulose nanofibers while water permeability was reduced because of the higher tortuosity induced by the nanocelluloses. In view of such properties, these materials are suggested as food packaging films.

Sign in / Sign up

Export Citation Format

Share Document