Reactivite des perfluorohalogenoalcanes en presence de couples metalliques—II: Formation de perfluoroolefines a partir des perfluoroiodoalcanes dans les solvants aprotiques dissociants, (DMSO,DMF, HMPT)

The action of zinc-copper couples on perfluoroiodoalkanes C₄F₉I, C₆F₁₃I and C₈F₁₇I was studied in DMSO, DMF, or HMPT; a mixture of isomeric perfluoroolefins was obtained. A general mechanism for the action of these metallic couples, involving a perfluorinated organometallic intermediate, is proposed.     

Kinetics of the iodine transfer polymerization of vinylidene fluoride

The kinetics of the iodine transfer polymerization (ITP) of vinylidene fluoride (VDF) was achieved in the presence of three different chain‐transfer agents (CTAs): 1‐iodoperfluorohexane (C₆F₁₃I), 1‐iodo‐2H,2H‐perfluorooctane (C₆F₁₃CH₂CF₂I), and 1,1,2,2‐tetrafluoro‐3‐iodopropane (HCF₂CF₂CH₂I). ITPs of VDF carried out in the presence of C₆F₁₃I and C₆F₁₃CH₂CF₂I showed the following: (1) a linear increase in DP_n versus α_VDF, which evidenced the controlled character of ITP, although the polydispersity indices were slightly high (ca 1.5), and (2) theoretical DP_n values close to the targeted ones. In contrast, neither of these statements was observed for the ITP of VDF in the presence of HCF₂CF₂CH₂I achieved under the same conditions, even if the synthesized oligomers could be reactivated. Although the C_Tr values of C₆F₁₃I and C₆F₁₃CH₂CF₂I were close (i.e., 7.7 at 75 °C), that of HCF₂CF₂CH₂I was lower (0.3 at 75 °C). The percentages of ? CF₂I and ? CH₂I functionalities were also assessed, and in the course of the reaction, a reduction of ? CF₂I end groups was noted. Then, the mechanism of the ITP of VDF was proposed. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5763–5777, 2006     

Reactivite comparee des perfluoroiodoalcanes (RFI) et des perfluoroalcoyl-2 iodo-1 ethanes (RFC2H4I) en presence de couple metallique zinc-cuivre dans les solvants phosphates d'alcoyles

Reactivity of perfluoroalkyl iodides R_FI and 1-perfluoroalkyl-2-iodoethanes R_FC₂H₄I, in presence of a zinc-copper couple in alkyl phosphates solvents, is described. R_FI and R_FC₂H₄I react via an organometalllc route to give per- and poly-fluoroorganozinc (R_FZnI and R_FC₂H₄ZnI) compounds. Then, in particular conditions, they react with alkyl to give phosphoro-fluorinated molecules (phosphinates, phosphine oxides, phosphines). The compounds's stabilities are studied.     

Synthese de polysiloxanes fluores. Partie II. Addition de thiols fluores sur des silanes insaturees

The addition of fluorinated thiols such as C₆F₁₃CH₂CH₂SH to silanes having an allylic or vinylic unsaturated group is described. A previous study on vinyl trimethylsilane and on chlorotrimethylsilane shows that the thiols react in a selective way, with the double bonds but not with the Si-Cl group. The addition compounds with chlorodimethyvinylsilane, dichloromethylvinylsilane, dichloromethylallylsilane and tetramethyltetravinylcyclotetrasiloxane are studied and identified by ¹H and ¹³C NMR. This new method of obtaining monomer silanes through a monoaddition reaction of fluorinated thiols gives the expected compounds with an excellent yield.     

Synthese d'ethers et de thioethers allyliques fluores par catalyse par transfert de phase

Several fluorinated allylic ethers, thioethers and diethers have been prepared in excellent yields by phase transfer catalysis (CTP). The used halogenated compounds are allyl chloride and bromide, p-chloromethylstyrene. The used fluorinated alcohols are aromatic pentafluorophenol and various aliphatics: CF₃CH₂OH, CF₂HCF₂CH₂OH ClCF₂CF₂CH₂OH,C₆F₁₃C₂H₄OH, HOCH₂CF₂CFClCF₂CH₂OH and HOC₆H₄C(CF₃)₂C₆H₄OH. All these new compounds have been characterized by ¹H and ¹³C NMR. We conclude that CTP is the best method to obtain allylic and diallylic compounds.     

Etude RMN du 13C de composes fluoroaliphatiques et de tensioactifs non ioniques perfluoroalkyles

Carbon-13 chemical shifts, spin-lattice relaxation times and nuclear Overhauser enhancement factors at 28°C are reported for a series of polyfluoroaliphatic compounds :

, and perfluoroalkyl nonionic surfactants C_mF_2m+1CH₂(OC₂H₄)_nOH with m = 6, 7 and n = 3, 4, 5, 6 and C₆F₁₃CH₂CH₂CONH(C₂H₄O)_nH with n = 3, 4. The influence of the perfluoroalkyl group on the ¹³C chemtcal shifts of the neighbouring hydrogenated carbons is discussed in terms of hyperconjugative type interactions between lone electron pairs on fluorine and the neighbouring CC or CO bond. Relaxation data show similar flexibilities of the fluorinated chains in the different molecules investigated. Nonionic surfactants exhibit segmental motions in both the hydrophobic perfluoroalkyl and the hydrophilic polyoxyethylene chains ; these motions appear to be similar to those of the analogous hydrogenated surfactants.     

Synthese de materiaux polymers transparents - Partie II Synthese et polymerisation d'acrylates et de methacrylates d'halogenoalkyle

Several fluorinated and chlorofluorinated acrylates and methacrylates were synthesized from the alcohols R_FCH₂OH with R_F=CCl₃, CHClCH₂CCl₃, (CF₂CFCl)_nCl, (C₂F₄)_nH, CF₃, C₇F₁₅ and C₆F₁₃CH₂. The corresponding polymers were also studied for their application as transparent polymeric materials. For this purpose the refractive indices n²⁰_D of the monomers and the polymers were measured as were the Tg values of the polymers. A study of their infrared spectra shows to what extent these products could be utilized taking into consideration their absorption in the long wavelength range between 0.85 and 1.50 m. The refractive indices of these polymers, which are reduced when increasing the number of fluorine atoms in the molecule, and that of the Tg measured between 50 and 70° C for the fluorinated methacrylates, indicate a potential use of these polymers as sheathing materials for optical fibres.     

Bis(fluoroalkyl)acrylic and methacrylic phosphate monomers, their polymers and some of their properties

Ten fluoromonomers of structure (R_FO)₂P(O)OCH₂CH₂OC(O)CRCH₂ were made in 30-64% yield by treating the chloridates (R_FO)₂P(O)Cl with HOCH₂CH₂OC(O)CRCH₂ in chloroform in the presence of triethylamine [R_F=CF₃CH₂, C₂F₅CH₂, C₃F₇CH₂, C₄F₉CH₂, C₄F₉CH₂CH₂ or C₆F₁₃CH₂CH₂; R  H or Me]. The chloromonomer (CCl₃CH₂O)₂P(O)OCH₂CH₂OC(O)CHCH₂ was obtained analogously in 29% yield. Polymerisation of the acrylate monomers, but not the methacrylate monomers, could be effected using α-azoisobutyronitrile as a radical initiator. Acrylic polymers having CF₃CH₂O, CCl₃CH₂O and C₆F₁₃CH₂CH₂O side-chains were obtained as translucent rubbers. Specimens of cotton fabric were treated with solutions of the polymers, and average water and oil repellency ratings measured. Fabric coated with the polymer with the C₆F₁₃CH₂CH₂O side-chain afforded protection from penetration of the test liquids. Treated fabrics were subjected to the limiting oxygen index (LOI) test according to BS EN ISO 4589-2 (1999): this test determines the point at which a material just burns in a volumetric flow of oxygen and nitrogen. The treated fabrics were more fire-resistant (LOI 22-29%) than the untreated fabric (LOI 18%). Fabric coated with the CCl₃CH₂O-based polymer can be considered fire-retardant (LOI 29%). The fluoromonomers were tested for anti-acetylcholinesterase activity and were found to be poor enzyme inhibitors; they are predicted to possess low acute toxicity.     

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.     

Pentafluorophenylcompounds of polyvalent iodine

The oxidation of C₆F₅I by oxidizers containing positive chlorine was investigated with the intention to prepare pentafluorophenyliodine (III) compounds: C₆F₅IX₂, where X are halides or oxoderivatives. Using ClF, ClOCF₃, Cl₂/AlCl₃ or Cl₂O as oxidizers C₆F₅ IF₂, C₆F₅ I Cl₂ and C₆F₅I (OCl)₂ - all thermally unstable - could be prepared and characterized.In contrast to these compounds the perfluoroaromatic carboxylates: C₆F₅I [O(O)C R_F]₂ are crystalline solids thermally stable up to 200 °C. Single crystal investigations show T-coordinated iodine with significant secondary bonding between iodine and the keto oxygens. C₆F₅ IO-formed by hydrolysis of C₆F₅IX₂ - changes if stored at RT forming (C₆F₅)₂I IO₃.(C₆F₅)₂I⁺ - formation is also observed when C₆F₅ IO is heated in inert (C₆F₅I, C₆H₆, CCl₄ …), protic (H₂O, CH₃OH, …) and strong acidic (FSO₃H …) dilution medium.C₆F₅IO reacts with acids, acid anhydrides and acid halides as could be shown by the preparation of C₆F₅ ICl₂ and C₆F₅ ICl (NO₃).Starting with C₆F₅ IX₂ different preparative ways for (C₆F₅)₂ I⁺ - compounds were successful. Principly (C₆F₅)₂ IX - compounds decompose thermally forming C₆F₅I + C₆F₅X.C₆F₅ IX₄ - compounds can be obtained from C₆F₅ IF₄ which is the specific displacement product of IF₅ with Si (C₆F₅)₄. By nucleophilic displacement it is possible to prepare C₆F₅ IF₂O, C₆F₅ IO₂, C₆F₅ IO (OAc_F)₂ and C₆F₅ I [OC(CH₃)₂  C(CH₃)₂O]₂,wich are all white, thermally stable solids.For the fluorine-ligand-exchange we used silycompounds as reagents. If the ligand is oxidable by C₆F₅ I(V) a stepwise reduction via C₆F₅I(III) to C₆F₅I could be shown by NMR-measurements.     

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.     

Addition thermique des iodo-1-perfluoroalcanes sur les perfluoroalkylethylenes

We have undertaken a study of the thermal addition of 1-iodo-perfluoroalkanes (C_nF_{2n + 1}I where n = 4, 6, 8) to perfluoroalkylethylenes (C_nF_{2n + 1} CHCH₂ where n = 4, 6, 8). Structures of the reaction products were established through spectroscopic or chemical identification and the optimal conditions for obtaining 1,2-bis(perfluoroalkyl)iodoethanes determined. The good yields thus obtained demonstrate the utility of this method of perfluoroalkylation.     

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.     

Synthese de polysiloxanes fluores. Partie IV. Obtention de disiloxanes fluores

New disiloxanes containing aromatic or aliphatic fluorinated groups are prepared and identified. The general formula of these compounds is: R_F-Q-CH₂-CH₂-Si(CH₃)₂-O-Si(CH₃)₂-CH₂-CH₂-Q′-R′_F · R_F and R′_F are halogenated groups such as C₆F₅-, C_nF_2n+1-, Cl(CFCl-CF₂)_n, CF₃-CFH-CF₂-, CF₃-, or CCl₃-. In most cases, Q or Q′ is an oxygen atom. Symmetrical disiloxanes are obtained by hydrolysis of corresponding fluorinated monochlorodimethylsilanes, and the asymmetrical ones are prepared in two steps by reacting the fluorinated olefins H₂C = CH-Q-R_F and H₂C = CH-Q′-R′_F with dihydrotetramethylsiloxane. The structures of these various compounds are elucidated by ¹H-, ¹³C- NMR and IR spectroscopy     

Pentafluorphenylverbindungen des Phosphors

Pentafluorophenyl Compounds of Phosphorus The preparation of compounds of the type R(C₆F₅)PX (R = CH₃, C₂H₅, t-C₄H₉ and C₆H₅: X = F, Cl, Br and N(C₂H₅)₂) is described. These derivatives are converted to trifluorophosphoranes, R(C₆F₅)PF₃, and phosphinic acid fluorides, R(C₆H₅)P(:O)F. The n.m.r. spectra are discussed.     

New types of asymmetrical bromonium salts [RF(RF′)Br]Y where RF and/or RF′ represent perfluorinated aryl, alkenyl, and alkynyl groups

A series of previously unknown asymmetrical fluorinated bis(aryl)bromonium, alkenyl(aryl)bromonium, and alkynyl(aryl)bromonium salts was prepared by reactions of C₆F₅BrF₂ or 4-CF₃C₆H₄BrF₂ with aryl group transfer reagents Ar′SiF₃ (Ar′ = C₆F₅, 4-FC₆H₄, C₆H₅) or perfluoroorganyl group transfer reagents R_F′BF₂ (R_F = C₆F₅, trans-CF₃CFCF, C₃F₇C≡C) preferentially in weakly coordinating solvents (CCl₃F, CCl₂FCClF₂, CH₂Cl₂, CF₃CH₂CHF₂ (PFP), CF₃CH₂CF₂CH₃ (PFB)). The presence of the base MeCN and the influence of the adducts R_F′BF₂·NCMe (R_F = C₆F₅, CF₃C≡C) on reactions aside to bromonium salt formation are discussed. Reactions of C₆F₅BrF₂ with Alk_F′BF₂ in PFP gave mainly C₆F₅Br and Alk_F′F (Alk_F′ = C₆F₁₃, C₆F₁₃CH₂CH₂), presumably, deriving from the unstable salts [C₆F₅(Alk_F′)Br]Y (Y = [Alk_F′BF₃]⁻). Prototypical reactivities of selected bromonium salts were investigated with the nucleophile I^-and the electrophile H⁺. [4-CF₃C₆H₄(C₆F₅)Br][BF₄] showed the conversion into 4-CF₃C₆H₄Br and C₆F₅I when reacted with [Bu₄N]I in MeCN. Perfluoroalkynylbromonium salts [C_nF_2n+1C≡C(R_F)Br][BF₄] slowly added HF when dissolved in aHF and formed [Z-C_nF_2n+1CFCH(R_F)Br][BF₄].     

Mono‐ and Perfluoroaryliodine(III) Cyano Compounds – Synthesis,Reactivity, and Structure

C₆F₅I(CN)₂ and x‐FC₆H₄I(CN)₂ (x = 2, 3, 4) were isolated from reactions of the corresponding aryliodine difluorides ArIF₂ and a stoichiometric excess of Me₃SiCN in CCl₃F (0 °C) or CH₂Cl₂ (20 °C), respectively. In addition, x‐FC₆H₄I(CN)₂ compounds were synthesized in good yields on alternative routes, namely from 3‐ or 4‐FC₆H₄I(OC(O)CH₃)₂ or 4‐FC₆H₄I(OC(O)CF₃)₂ or from 4‐FC₆H₄IO and Me₃SiCN in CH₂Cl₂ at 20 °C. In the 1 : 1 reaction of C₆F₅IF₂ and Me₃SiCN a lower temperature was necessary to suppress partial disubstitution and to obtain the first example of a new type of aryliodine(III) cyanide compounds, C₆F₅I(CN)F. 4‐FC₆H₄I(CN)F could be isolated from the equimolar reaction of 4‐FC₆H₄IF₂ and Me₃SiCN in CH₂Cl₂ even at 20 °C. The new products were characterized by multi‐NMR and Raman spectroscopy. The molecular structures of C₆F₅I(CN)₂, 3‐ and 4‐FC₆H₄I(CN)₂, C₆F₅I(CN)F, and 4‐FC₆H₄I(CN)F are discussed and compared with that of C₆F₅IF₂. The reactivity of C₆F₅I(CN)F towards fluoride acceptors EF_n (BF₃, AsF₅) and R_xEX_?x (C₆F₅SiF₃, C₆H₅SiF₃, C₆H₅PF₄, Me₃SiCl, Me₃SiC₆F₅) were investigated and showed differing reaction patterns (fluoride abstraction, aryl transfer, chloride transfer). Besides the molecular entities C₆F₅I(CN)F and C₆F₅I(CN)Cl, the corresponding iodonium salts [C₆F₅(CN)I][BF₄] and [C₆F₅(CN)I][AsF₆] were isolated. The thermal stability of ArI(CN)₂ and ArI(CN)F, neat and in solution, as well as the reactivity of 4‐FC₆H₄I(CN)₂ towards the Lewis acid BF₃ are reported.     

Fluorinated tropylium ions in the mass spectra of some polyfluoroaromatic compounds

The most prominent ion in the mass spectra of C₆F₅CH₂X (X ? H, Br, CH:CH₂, COCl, and CH₂C₆F₅) is C₇F₅H₂⁺, formulated as the pentafluorotropylium cation. This ion is also found, in an amount comparable to the parent ion, in the spectrum of (C₆F₅)₂CH₂. The heptafluorotropylium cation is found similarly in the spectrum of C₆F₅CF₃. The mass spectra of (C₆F₅)₂CHBr and [(C₆H₅)₂CH]₂ exhibit an ion C₁₃F₁₀H⁺ as the base peak, which is probably a pentafluorophenylpentafluorotropylium cation. The alcohol (C₆F₅)₂CHOH shows loss of C₆F₅, followed by 2H, as a major breakdown pathway. The mode of formation, and the subsequent fragmentation, of the major ions in these spectra, are discussed.     

Influence de la solvatation preferentielle sur les dimensions des polymeres en solution dans des melanges de solvants

We have studied the dependence of the intrinsic viscosity number of polymers on the composition of binary solvents. The systems studied are: polystyrene in CCl₄/CH₃OH, C₆H₆/CH₃OH and C₆H₆/heptane and poly-2-vinylpyridine in CHCl₃/CH₃CH₂OH. We have also studied, for the same systems, preferential solvation of the polymers, using light scattering.We have observed that, near the θ point, short polystyrene chains exhibit a higher expansion than long chains. This was explained in terms of the dependence of preferential solvation on molecular weight.For the system poly-2-vinylpyridine/CH₃CH₂OH/CHCl₃, we have established the viscosity increment dependence on solvent composition. The curve describing this increment differs markedly from the theoretical curve based on G^E values (excess free energy) of the solvent mixture. However, taking into consideration the process of preferential solvation, the experimental curve can be corrected and becomes very similar in shape to the theoretical curve but there still remains a quantitative difference between the two curves.     

Reactivite des derives organomanganeux—VIII : Préparation de cétones par acylation d'organomanganeux. Influence de la nature de l'agent acylant,des solvants et des ligands

The influence of the nature of acylating reagents, solvents and ligands on the preparation of ketones by acylation of organomanganous reagents is studied. Thus acid chlorides in ether, symmetrical acid anhydrides in ether or THF and mixed carboxylic-carbonic anhydrides (R'COOCOOEt) in ether are compared, they lead to the corresponding ketones with good or excellent yields. Some problems of reproductibility are encountered and discussed when mixed anhydrides R'COOCOOEt are used in THF. The addition of a great variety of cosolvents (e.g. C₆H₆, AcOEt, CO₃Et₂, CH₂CN, CH₂CL₂, . .) to the reaction mixture before addition of the acylating reagent does not affect the yield of ketones. In comparison the complexation of organomanganous reagents by several ligands (e.g. Me₂S or Ph₃P) has no subsequent effect on their acylation. The main limitation for the choice of solvents or ligands is the use of amino derivatives which generally lead to a very low yield of ketones (e.g. C₅H₅N, TMEDA, Et₃N) or unreproducible yields (e.g. HMPA). Two applications of these studies are described:The stabilization of s or t-alkyl manganous derivatives by complexation which leads to the best yield of the corresponding ketonesThe use of a cosolvent in order to increase the yield when mixed anhydrides R'COOCOOEt are used in THF.