Thermal and photolytic stabilities of perfluoroalkane sulfonic acids and their derivatives

The use of perfluoroalkanesulfonic acids and their derivatives in drastic conditions leads us to study their behaviour with respect to temperature and radiative factors.Such acids as CF₃SO₃H and C₂F₅SO₃H, used in a pure state as well as their related pure anhydride are stable until they reach a temperature of at least 180°C.On the other hand, the solutions of anhydride with its related acid, yield perfluorosulfonic esters and SO₂ at room temperature already:

This mechanism is discussed.These results involve a new and easy synthesis of symmetrical perfluorosulfonic esters R_FSO₃R_F with acids and P₂O₅.

Further more, it occurs no transformation of the anhydride under UV and visible irradiation. But under the same conditions, a small account of acids are deshydrated into anhydrides.A further experiment combining both effects of temperature and light leads to the esters.     

Thermolyse des anhydrides perfluoroalcanesulfoniques. Mecanisme et application a la synthese des esters RFSO3RF.

Perfluoroalkanesulfonic anhydrides [(R_FSO₂)₂O; R_F=CF₃,C₂F₅,C₄F₉], mixed with the parent acid, decompose thermally to give the corresponding perfluoroalkyl perfluoroalkanesulfonates (R_FSO₃R_F) with liberation of SO₂. If the perfluoroalkyl moieties in the anhydride and the acid are different, a mixture of symmetric and unsymmetric esters is obtained. An ionic bimolecular mechanism is deduced from the results, and a new easy synthesis of the symmetric perfluorinated sulfonic esters is proposed.     

Oxydation anodique de iodoperfluoroalcanes dans les acides perfluoroalcanesulfoniques. Preparation de nouveaux esters sulfoniques totalement fluores RFSO3R'F a longues chaines

Perfluorinated sulphonic esters R_FSO₃R'_F and fluorosulphates FSO₃R'_F, are easily obtained by anodic oxidation of iodoperfluoroalkanes R'_FI in perfluoroalkane sulphonic acids R_FSO₃H (R_F  CF₃, C₂F₅, C₄F₉) and fluorosulphuric acid. With di-iodo compound I(CF₂)₄I, the mono and the diester can be selectively obtained. The alkaline hydrolysis of these esters produces perfluorinated carboxylic compounds. Polyfluorinated iodide R'_FCH₂CH₂I are also oxidized in similar conditions. The mechanism of the electrolytic reaction is discussed.     

The syntheses of fluorinated alkanesulfonamides and poly-(fluorinated alkanesulfonamides)

In order to synthesize poly-(fluorinated alkanesulfonamides) a series of model experiments were carried out: (1) reactions of fluorinated alkanesulfonyl fluorides with amines, (2) reactions of fluorinated alkanesulfonyl chloride with amines and (3) reactions of sodium salts of fluorinated alkanesulfonamides with alkyl iodides of fluorinated alkanesulfonic acid esters. Seventeen new fluorinated alkanesulfonamides were prepared in good yields, namely: R_FO(CF₂)₂SO₂NR¹R² (1a-h), R¹R²NSO₂R_FSO₂NR¹R² (2a-h) and [Cl (CF₂)₄O(CF₂)₂SO₂NH(CH₂)₃]₂ (3). Reaction of R_FSO₂NH₂ with equivalent amount of NaOCH₃ and methyl iodide was shown to give both the N-mono- and N,N-di-substituted amides. Consequently the N-monosubstituted alkanesulfonamides were chosen as monomers for syntheses of the poly-(fluorinated alkanesulfonamides) and two new polymers were synthesized. The effect of the condition of the polycondensation on M?_n of the polymers were discussed and elemental composition, ¹⁹F NMR, IR, M?_n, Tg, tensile strength, thermal and chemical stabilities of the polymers were measured. Several new perfluoroalkanesulfonyl chlorides CISO₂R_FSO₂Cl (4a-c) and fluorinated alkanesulfonic acid esters (6a-d) were synthesized. However, reaction of CFCl₂CF₂O(CF₂)₂SO₂F with AlCl₃ was found to give Cl₃CCF₂O(CF₂)₂SO₂F (5) instead of the expected sulfonyl chloride.     

SO2F2‐Mediated One‐Pot Synthesis of Aryl Carboxylic Acids and Esters from Phenols through a Pd‐Catalyzed Insertion of Carbon Monoxide

A one‐pot Pd‐catalyzed carbonylation of phenols into their corresponding aryl carboxylic acids and esters through the insertion of carbon monoxide has been developed. This procedure offers a direct synthesis of aryl carboxylic acids and esters from inexpensive and abundant starting materials (phenols, SO₂F₂ and CO) under mild conditions. This method tolerates a broad range of functional groups and is also applicable for the modification of complicated natural products.     

Mise au point d'un procede de preparation catalytique de perfluoroalkyl sulfonamide par addition d'ethylamine a un chlorure d'acide perfluoroalcane sulfonique

Addition of N-ethylamine to a perfluoroalkylsulfonic acid chloride R_FSO₂Cl has been studied, to obtain the corresponding perfluoroalkylsulfonamide R_FSO₂NHC₂H₅. First a two-step synthesis has been considered : transformation of the perfluoroalkylsulfonic acid chloride R_FSO₂Cl to the corresponding fluoride R_FSO₂F, and addition of N-ethylamine; the study of the first step is reported. Then, a sulfonamide one-step synthesis involving a fluoride catalysis, is described.     

Thermolyse des halogenures de perfluoroalcanesulfonyle

Perfluoroalkanesulfonyl chlorides [R_FSO₂Cl ; R_F  CF₃, C₂F₃, C₄F₉], decompose thermally to give the corresponding perfluoroalkyl chlorides with evolution of SO₂. The latter retards the reaction, but it is catalysed by copper which also inhibits the SO₂ effect. 2-methyl-2-nitrosopropane traps the perfluoroalkyl free radicals. In the presence of a perfluoroalkyl iodide [R′_FI ≠ R′_F≠R_F], other products, R_FI and R_FCl, are obtained. A free radical chain-mechanism is then suggested.On the other hand, perfluorobutanesulfonyl fluoride is very stable thermally.     

Some approaches to the synthesis of fluorinated alcohols and esters. I. Completely fluorinated esters from the hunsdiecker reaction of silver F-alkanoates with iodine

A completely fluorinated ester of the type R_FCO₂CF₂R_F′ was obtained from reaction of silver 3,6,9-trioxa-F-undecanoate and iodine with a diluent at 130°. This new substance resembled closely the previously prepared 1,1-dichloro-F-alkyl esters and was hydrolytically and thermally labile. Substitution products, R_FCOY (Y = nucleophile) and pyrolysis products, R_FCOF and R_F′COF were isolated and characterized. It appears probable that the acyl hypoiodite and the iodo-F-alkane reacted by an S_Ei-type process to give the completely fluorinated ester.     

Synthesis and reactions of phenyliodonium bis(perfluoroalkanesulfonyl) methides

Phenyliodonium bis(perfluoroalkanesulfonyl) methides PhI⁺ ⁻C(SO₂R_F)₂ ( 3 ) were prepared by the reaction of bis(perfluoroalkanesulfonyl)methanes with diacetoxyiodobenzene. The photochemical reactions of 3 with alkenes, methanol, bromine, and benzene gave the corresponding addition or insertion products. When 3 was irradiated in the presence of methyl sulfide, pyridine, and triphenylphosphine, it afforded the ylides containing the bis(perfluoroalkanesulfonyl)methylene functionality, Y⁺ ⁻C(SO₂R_F)₂. In these reactions the bis(perfluoroalkanesulfonyl)carbene intermediate (R_FSO₂)₂C: may be involved. Irradiation or heating of 3 in DMSO gave a 1 : 1 complex, the structure of which was confirmed by X-ray diffraction analysis. Bis(perfluoroalkanesulfonyl)-methylene dimethyloxosulfonium ylides Me₂(O)S⁺ ⁻C(SO₂R_F)₂ were obtained by air oxidation of bis(perfluoroalkanesulfonyl)methylene dimethylsulfonium ylides.     

Synthesis of symmetric and dissymetric bisperfluoroalkanesulfonylimides and evaluation of their inhibition on bovine carbonic anhydrase

This study describes a synthesis of symmetric and dissymmetric bis[(perfluoroalkane)‐sulfonyl]imides by the reaction of the sodium salt of perfluoroalkanesulfonamide R_FSO₂NH⁻Na⁺ (R_F = C₄F₉, C₆F₁₃, C₈F₁₇) with hexamethyldisilazane and perfluoroalkanesulfonylfluoride R_FSO₂F (R_F = C₄F₉, C₆F₁₃, C₈F₁₇). They are obtained, in two steps, in moderate overall yield. Moreover, this paper provides a study of their inhibition on bovine carbonic anhydrase. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:542–548, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20452     

New fluorinated polysiloxanes containing an ester function in the spacer. I. Synthesis and characterization

Unsaturated perfluoroalkyl esters derived from undecylenic acid: CH₂?CH? (CH₂)₈? COO? CH₂? CH₂? R_F (with R_F?C₆F₁₃, 2a and R_F?C₈F₁₇, 2b ) and C₈F₁₇? (CH₂)₁₀? COO? CH₂? CH?CH₂, 2c were prepared with excellent yields. Their hydrosilylation by methylhydrodimethylsiloxane copolymers of various Si? H contents gives new fluorinated polysiloxanes which were examined by ¹H- and ¹³C-NMR, GPC, differential scanning calorimetry, and optical polarizing microscopy. Polymers derived from compounds 2a and 2b exhibit mesomorphic structures. © 1994 John Wiley & Sons, Inc.     

A relation between RF values of unidimensional and circular paper chromatography

1. R_F values of 12 amino acids were determined in phenol-water and benzyl alcohol-acetic acid-water using unidimensional and circular techniques of paper chromatography. 2. It has been observed that the square of circular R_F values (considering frontal boundary of solute) equals the linear R_F values, and this relation is valid for the amino acids as well as the sugars studied. 3. The relation is found to be independent of the distance traversed by the solvent in the case of both amino acids and sugars. 4. A theoretical support has been given to the experimental observations.     

Pseudohalogenverbindungen. XX. Perfluorierte alkan- und phenylsulfonylpseudohalogenide

The pseudohalide CF₃SO₂NCO has been synthesized by means of a new reaction involving trifluoromethanesulphonamide and chlorosulphonylisocyanate. This method may be used for preparing other perfluorinated alkanesulphonyl-, arenesulphonyl- and alkanecarbonyl-amides. Reactions of CF₃SO₂NCO with alcohols, thiols, phenols and amines lead to the corresponding carbonic acid esters, thio-esters, phenyl esters and ureas. Reactions with carbonic acids, aldehydes and dimethylsulphoxide gave CO₂ and the corresponding acid amides, azomethines and imino-dimethylsulphurane. Under pressure at 160°C, CF₃SO₂NCO reacts with phosphorus pentasulphide to give the previously unknown compound CF₃SO₂NCS; with phosphorus pentachloride under the same conditions, CF₃SO₂NCCl₂ is formed.     

Reactivite des perfluoroiodoalcanes avec les carbonates et pyrocarbonates d'alcoyles en presence de couple metallique zinc-cuivre

Perfluoroalkyl iodides R_FI, in dissociating solvents, in the presence of zinc-copper couple give perfluoroorganic compounds R_FZnl, which react with alkyl carbonates and pyrocarbonates to give perfluorocarboxylic acids and perfluorocarboxylic esters of industrial interest.     

Vapor phase synthesis of phthalate esters from benzene and maleic anhydride over CrO3/magnesol and SO42-/ZrO2+

Benzene and maleic anhydride react over solid acids, viz. CrO₃/Magnesol and SO₄ ^2-/ZrO₂ catalysts to form phthalic anhydride and olefins, which in turn produce phthalate esters as end products. Based on the product distribution, a reaction pathway is proposed.     

Radical addition of RFI to alkenylsuccinic anhydrides and gem-substituted alkenyl triesters : Zinc and radical induced, or spontaneous radical cyclization, of the δ-iodoalkanoic esters to γ-lactones

Radical addition of R_FI to alkenylsuccinic anhydrides affords ω-(perfluoroalkyl)-δ-iodoalkyl-2-butane-1,4-dioc acid anhydrides, and these adducts are reductively dehalogenated and esterified by zinc and acid in ethanol without lactonization. However, the R_FI adducts react with KOH in ethanol to give the alkenyl half esters (but no γ-lactone), which convert to the γ-lactones by acid catalysis. When treated with water, ethanol, Zn and 48% HBr, the R_FI adduct from but-3-en-2-yl-succinic anhydride converts to the iodo half ester, R_FCH₂CHICH(CH₃)CH(CO₂H)CH₂CO₂Et, which undergoes Zn induced (S_Hi) conversion to γ-lactone. R_FI (AIBN) and the triester CH₂CHCH₂C(CO₂Et)₂CH₂CO₂Et yield R_FCH₂CHICH₂C(CO₂Et)₂CH₂CO₂Et (95%). When heated to 140 °C, the adduct loses iodoethane.and cyclizes to diester γ-lactones (94%). With benzoyl peroxide, R_FI and the triester at 99 °C, spontaneous radical cyclization of the adduct to lactone occurs. Evidently, the gem-disubstituted triester readily forms a five-membered lactone as a consequence of steric compression in the open chain form.     

Polyfluoroalkyl <Emphasis Type="Italic">N</Emphasis>-(trifluoromethylsulfonyl)amidosulfites,number one stable NH-containing amidosulfites

We prepared for the first time NH-containing amidosulfites, polyfluoroalkyl N-(trifluoro-methylsulfonyl) amidosulfites CF₃SO₂NHS(O)OR_F, by reaction of N-sulfinyl-trifluoromethanesulfonamide CF₃SO₂N=S=O with alcohols R_FOH. Amidosulfites were formed also in reaction of chlorosulfites R_FOS(O)Cl with trifluoromethanesulfonamide, with its sodium salt, and N-trimethylsilyl derivative.     

Paradigm Shift from Alkaline (Earth) Metals to Early Transition Metals in Fluoroorganometal Chemistry: Perfluoroalkyl Titanocene(III) Reagents Prepared via Not Titanocene(II) but Titanocene(III) Species

Perfluoroalkyl (R_F) titanocene reagents [Cp₂Ti^IIIR_F] synthesized via [Cp₂Ti^IIICl] rather than [Cp₂Ti^II] show new types of perfluoroalkylation reactions. The [Cp₂Ti^IIIR_F] reagents exhibit a wide variety of reactivity with carbonyl compounds including esters and nitriles, and selectivities far higher than those reported for conventional R_FLi and R_FMgX reagents.     

The reaction of perfluoroalkanesulfinates VII. Fenton reagent-initiated addition of sodium perfluoroalkanesulfinates to alkenes

The addition of sodium perfluoroalkanesulfinates (R_FSO₃Na) to various olefins (CH₂=CHR) initiated by Fenton reagent (Fe²⁺-H₂O₃) in the presence of sodium azide gave the adducts R_FCH₃-CHN₃R in good yield. A radical mechanism was proposed based on the EPR and other evidences. The adducts were readily reduced through catalytic hydrogenation to give the corresponding amines R_FCH₂CH(NH₃)R in high yield. The reaction represents a convenient and effective route to these useful organofluorine compounds.     

Studies on sulfinatodehalogenation XXI. A new and convenient syntheses of 2-(F-alkyl) aldehydes,alcohols, acids and ketones

Reaction of perfluoroalkyl iodides ( 1a–e ) with the unsaturated ethers such as 1-ethoxy-1-propene (2) , 1-methoxy-1-butene (3) under the sulfinatodehalogenation condition gave the corresponding 2-(F-alkyl) propanals ( 5a–e ) and butanals ( 6c, d ) very readily in high yield, which were converted to 2,4-dinitrophenylhydrazones ( 7a–e, 8c, d ) and characterized. The reaction products 5 and 6 were oxidized with Jone's reagent and reduced with NaBH₄ in ethanol to give the corresponding acids ( 9, 10 ) and alcohols ( 11, 12 ) in good yield. Treatment of compounds 5 and 6 with pyridine gave the dehydrofluorination products 13 and 14 . Under the same condition, perfluoroalkyl iodide reacted with 2-ethoxy-1-propene (4) only to form R_FSO₂Na and R_FH as the major products, but in aqueuous DMF (DMF: H₂O = 5:1) to give the perfluoroalkylacetone (15) in good yield. Thus, the reaction provides a convenient, effective new method for syntheses of these useful organofluorine intermediates.