Yves Hervaud

Synthesis of Dialkyl-Hydroxymethylphosphonates in Heterogeneous Conditions

This article describes the synthesis of a series of dialkyl-hydroxymethylphosphonates bearing various alkyl ester groups by the Pudovik reaction. The employed method uses anhydrous potassium carbonate as a catalyst in heterogeneous (solid/liquid) or mixed (solid/liquid and homogenous) conditions. All these syntheses are performed without any phase transfer agent and involve an anionic intermediate in a low polar or apolar solvent. These different products, obtained with high yields, have been characterised by 1 H and 31 P NMR and also by mass spectrometry. A study of fragmentation in the FAB ionisation process is given.

Synthesis of new phosphonic derivatives with fluorinated chains

Abstract The synthesis of phosphonic derivatives (phosphonates and phosphonic acids) bearing fluorinated chains is presented. Such compounds with different spacers between these groups have been produced mainly by the telomerization of ω-unsaturated phosphonic derivatives with fluorinated transfer agents such as mercaptans. The fluorinated phosphonates were quantitatively hydrolyzed to fluorinated phosphonic acids via two pathways: a classical one involving acids and another via silylation. Most products have been characterized by NMR and mass spectroscopy.

Etude de la télomérisation et de la cotélomérisation du fluorure de vinylidéne (VF2). Part I. Cotélomérisation du VF2 avec l'acétate de vinyle et le 2-hydroxyéthylmercaptan

Abstract The radical telomerization of vinylidene fluoride (VF 2 ) and of vinyl acetate (VAc) with 2-hydroxyethylmercaptan, and the radical cotelomerization of both monomers with the same thiol have been investigated. In each case, the chemical structures and the chain lengths have been determined by various methods in order to understand the reactivity and the direction of addition of both monomers. This study indicates a greater reactivity for VAc relative to VF 2 since a twofold excess of VAc may be introduced into the cotelomers for an equimolar initial feed concentration of the monomers. Of the telomers produced, it was noted that the diadduct is HOCH 2 CH 2 SCH 2 CF 2 CH 2 CH 2 OCOCH 3 , indicating that the thiyle radical reacts preferentially with VF 2 . This study is a preliminary to obtaining curable VF2 oligomers.

SYNTHESE DE COMPOSES PHOSPHONIQUES A CHAINE CHLOROFLUOREE. PARTIE II TELOMERISATION DE L'ALLYL ET DU VINYL PHOSPHONATE DE DIETHYLE

Abstract The synthesis of compounds containing both a phosphonic end group and a chlorofluorinated chain is achieved by means of a redox reaction using cuprous chloride as catalyst. By a redox catalysis system monoadducts are obtained. The taxogens involved are diethyl vinylphosphonate and diethyl allylphosphonate. The telogens are CF3[sbnd]CCl3 and CCl3[sbnd](CF2[sbnd]CFCl) n [sbnd]Cl. The resulting products contain a C[sbnd]P bond. Their structure has been determined by 1H NMR. The hydrolysis of phosphonic esters is carried out with concentrated hydrochloric acid and leads to the corresponding acids and salts.

Synthesis of ion exchange membranes from ozonized high density polyethylene

The synthesis and the characterization of graft copolymers prepared from ozonized high density polyethylene (HDPE) are described. The powder of HDPE was treated with ozone in well defined conditions and then copolymerized with monomers, such as, acrylic acid (AA), N,N-dimethylamino-2 ethylmethacrylate (MADAME) and vinyl phosphonic acid (VPA). Cationic exchange membranes were prepared from the grafted copolymers of AA and VPA and anionic exchange membrane from the grafted copolymer of MADAME. The obtained copolymers were characterized by the grafting rate, FTIR spectroscopy, scaning electronic microscopy, thickness, exchange capacity and electrical resistance.

SYNTHESIS OF THIOLS BEARING PHOSPHONATE GROUPS

Abstract Two phosphonated compounds bearing a mercaptan group have been prepared. These thiols are: HSCH2CO2 (CH2)2S(CH2)3PO(OEt)2 (I) and HS(CH2)3PO(OEt)2 (II). Both originate from diethyl allylphosphonate. (I) with mercaptoethanol and thioglycolic acid and (II) with thioacetic acid. (I) is obtained in two steps, firstly by addition of mercaptoethanol on diethyl allylphosphonate and secondly by esterification of the previous compound with thioglycolic acid (total yield 70%). In the same manner, (II) is obtained by addition of thioacetic acid followed by hydrolysis by KCN in methanol (total yield 90%).

Study of vinylidene fluoride (VF2) telomerization and cotelomerization. Part II. VF2 and chlorotrifluoroethylene (CTFE) cotelomerization with 2-hydroxyethylmercaptan by radical initiation

Abstract The radical telomerization of vinylidene fluoride (VF2) and of chlorotrifluoroethylene (CTFE) with 2-hydroxyethylmercaptan as the telogen was investigated. The corresponding homotelomers R-S- (CF2-CFCl)n-H (Cn) and R-- (CH2-CF2)n-H (Vn) with R =- -CH2CH2OH were synthesized and the 1:1 adducts identified. The VF2/CTFE/thiol reaction gave a mixture of the expected products, homotelomers and cotelomers. By various methods, mainly by 19F NMR spectroscopy, the chain length and tacticity of these telomers were determined. For example, after analysis, a fraction of the cotelomers was in good agreement with the general formula HO-CH2-CH2-S- (CF2-CFCl)x- (CH2-CF2)y-H, with x and y close to 4. Moreover, by comparison with the spectra of homotelomers of VF2 and CTFE, it was shown that these cotelomers exhibit an alternating structure.

Synthese et Etude Structurale D'acides Alkylphosphoniques a Longue Chaine Hydrocarbonee

Long-chain dialkyl alkylphosphonates were synthesized by radical addition of dialkyl hydrogenphosphonates onto alkenes in presence of di(t-butyl) peroxide. This synthetic route leads to high yields between 94 and 97%. We performed chemical modifications of these phosphonates in order to obtain acidic derivatives. The structure of these compounds was characterized by NMR analyses and mass spectroscopy. We also studied their thermal behaviour and various crystalline phases were put in evidence by differential scanning calorimetry and optical microscopy. The thermal stability of these compounds was compared by thermogravimetric analyses.

SYNTHESE DE COMPOSES PHOSPHONIQUES [Agrave] CHAINE CHLOROFLUOREE‐PARTIE III

Abstract Preparation of compounds containing chlorofluorinated chains and [sbnd]CH2I or [sbnd]CH2[sbnd]CH[dbnd]CH[sbnd]CH2Cl end groups was carried out either through classical chemical synthesis on using telomerization of Cl3C[sbnd](CF2[sbnd]CFCl) n [sbnd]Cl and CF3[sbnd]CCl3 with butadiene. Triethylphosphite does not react upon telomers presenting an iodinated termination even if it is a [sbnd]CH2[sbnd]CH2[sbnd]I end group. Contrasting with this behaviour, butadiene derivatives lead to the expected phosphonates, when the chain contains three halogenated C atoms: RF.Cl[sbnd]CCl2[sbnd]CH2[sbnd]CH[dbnd]CH[sbnd]CH2[sbnd]P(O)(OEt)2 with RF.Cl=[sbnd]CF3.[sbnd]CF2[sbnd]CFCl2. For the higher homologs, dienes are formed following the action of P(OEt)3 upon the [sbnd]CFCl group present in the chain.

Synthesis of a New Phosphonate Methacrylate Monomer

In this work, a new methacrylate phosphonate monomer synthesis was described according to a two-step reaction. First the monoaddition of thioglycolic acid onto dimethylvinyl phosphonate monomer led to dimethyl–5-carboxymethyl-2-thiaethylphosphonate, a new phosphonate acid compound. This reaction also led to the thioester homologue of dimethyl–5-carboxymethyl-2-thiaethylphosphonate with a 15% yield by reaction of a thioglycolic acid thioester with dimethylvinyl phosphonate. Second, dimethyl carboxy-4-thia-butyl phosphonate reacted with glycidyl methacrylate. This epoxy-acid addition reaction was catalyzed by chromium salt at 70°C and led to the new methacrylate phosphonate monomer. We showed that only the secondary alcohol was obtained via a β addition. The two-step reaction final yield was calculated to be about 85%.