Tokio Hagiwara

UNIQUE RADICAL ADDITION REACTIONS ONTO PERFLUORO-ENOL ESTERS

Abstract 2-Benzoyloxy-F-propene, an F-enol ester, is shown to serve as a good and selective acceptor towards nucleophilic radicals generated from cyclic ethers, alcohols, and alkyl iodides to afford the addition product. The scope and synthetic utility of the radical addition reaction are described.

Radical polyaddition of bis(α-trifluoromethyl-β-difluorovinyl) terephthalate with 1,4-dioxane

To develop a radical polyaddition reaction of 2-benzoyloxypentafluoropropene [CF2C(CF3)-OCOC6H5] (BPFP) with tetrahydrofuran (THF), the reactions of bis(α-trifluoromethyl-β-difluorovinyl) terephthalate [CF2C(CF3)OCOC6H4COOC(CF3)CF2] (BFP) with THF and of BPFP with 1,4-dioxane were investigated as model reactions to form 1 : 1 and 1:2 addition products of BFP with THF. This evidenced that THF is monofunctional, and dioxane is bifunctional since the 1:1 and 2:1 addition products of BPFP with dioxane were formed. The polyaddition reaction of BFP with dioxane turned out to produce a white powdery substance which was found to possess a mole ratio of BFP units to dioxane units in the polymers of 1:1. The highest molecular weight obtained was Mn = 9.9 × 103.

Novel fluorinated polymers by radical polyaddition of bis(α-trifluoromethyl-β-difluorovinyl) dicarboxylate with ether

o develop the radical polyaddition reaction of bis(a-trifluoromethyl-β-difluorovinyl) terephthalate (BFP) with 1,4-dioxane, bis(a-trifluoromethyl-β-difluorovinyl) cyclohexane-1,4-dicarbocylate (FDFC) and bis(a-trifluoromethyl-β-difluorovinyl) adipate (FDFA) were prepared and polyadditions with 1,4-dioxane, diethyl ether, and 1,2-dimethoxyethane were examined in the presence of benzoyl peroxide (BPO). The molecular weight of the polymer obtained from FDFC with dioxane was 2.9X10 3 . A polymer with a molecular weight of 4.5X10 3 was obtained by the reaction of FDFA with 1,4-dioxane initiated with BPO. Polyaddition reactions of FDFC or FDFA with 1,2-dimethoxyethane or diethyl ether were found to produce linear polymers which are soluble in common organic solvents. These results suggested that 1,4-dioxane, diethyl ether and 1,2-dimethoxyethane work as monomers in this reaction system. Postpolymerization of the polymer obtained from BFP with 1,4-dioxane was also examined to yield a polymer of higher molecular weight compared to that of the starting polymer. A postulated polymeratization mechanism of BFP with 1,4-dioxane is briefly discussed.

Long‐Term Stabilization of the Activity of Ascorbate Oxidase Adsorbed on a Porous Carbon Material by Polymaleimidostyrene

Abstract The biological catalysts adsorbed on the carbon surface gradually lost their activities. In order to prolong stabilization of the enzyme activity, polymaleimidostyrene (PMS) was used to preserve enzyme conformation. Sulfhydryl and amino groups of enzyme or biological tissue can be covalently bound to PMS. By using the carbon material coated by PMS, the stability of L‐ascorbic acid sensor response using purified enzyme was significantly improved, and its initial response was not decreased at all for 150 days, although the purified enzymes adsorbed to the carbon without PMS lost their activity 22.5% after 10 days.

RADICAL ADDITION REACTION OF 2-BENZOYLOXYPENTAFLUOROPROPENE ONTO CYCLOALKANES

Abstract The radical addition reactions of 2-benzoyloxypentafluoropropene [CF 2 C(CF 3 )OCOC 6 H 5 ] (BPFP), an F -enol ester, with cyclopentane, cyclohexane and cycloheptane in the presence of benzoyl peroxide are shown to afford the 1:1 addition products of BPFP with the cycloalkanes. The structures of the reaction products were confirmed by the mass spectra and 1 H , 13 C and 19 F NMR measurements. Similar additions of perfluoroisopropenyl cyclohexanecarboxylate with cycloalkanes were also investigated.

Anionic polymerization reactivity of 1,2,2-trifluorostyrene

Abstract The anionic polymerization of 1,2,2-trifluorostyrene (CF 2 CFC 6 H 5 ) (TFS) has been undertaken with a view to obtaining preliminary information on the reactivity of TFS which is hardly polymerized under radical polymerization conditions. The solid polymer of TFS was obtained following initiation with triethylaluminum complexed with active methylene chelate compounds although the yields of the polymer were rather low. The characteristic feature of this polymerization system is that the molecular weight distribution of the poly(TFS) obtained is very narrow. The polymer was shown to be produced by an addition polymerization mechanism by analyzing its 1 H and 13 C NMR spectra.

Anionic polymerization of fluorine-containing vinyl monomers. 11. α-Fluoroacrylates

Abstract The polymerization conditions of methyl α-fluoroacrylate (H 2 CCFCOOCH 3 ) and 2,2,2-trifluoroethylα-fluoroacrylate (H 2 CCFCOOCH 2 CF 3 ) have been investigated by systematicallysurveying the typical anionic polymerization initiators and solvents in order toobtain preliminary information on the general trend of the anionic polymerization offluorinated acrylates. It is concluded that α-fluoroacrylates are polymerized by initiatorsof relatively low basicity which are incapable of producing polymers of non-fluorinatedacrylates and methacrylates. No remarkable side reactions occurred since the molecularweight distributions were unimodal and no peaks assignable to vinyl protons or otheradditional signals were observed in the 1 H NMR spectra. The polymerization took placein an anionic fashion as established from an investigation of the initiation reaction.

Synthesis and polymerization of N‐(4‐tetrahydropyranyl‐oxyphenyl)maleimide

N-(4-Tetrahydropyranyl-oxy-phenyl)maleimide (THPMI) was prepared and polymerized by radical or anionic initiators. THPMI could be polymerized by 2,2′-azobis(isobutyronitrile) (AIBN) and potassium tert-butoxide. Radical polymers (poly(THPMI)r) were obtained in 15–50% yields for AIBN in THF at 65°C after 2–5 h. The yield of anionic polymers (poly(THPMI)a) obtained from potassium tert-butoxide in THF at 0°C after 20 h was 91%. The molecular weights of poly(THPMI)r and poly(THPMI)a were Mn = 2750–3300 (Mw/Mn = 1.2–3.3) and Mn = 11300 (Mw/Mn = 6.0), respectively. The difference in molecular weights of the polymers was due to the differences in the termination mechanism of polymerization and the solubility of these polymers in THF. The thermal decomposition temperatures were 205 and 365°C. The first decomposition step was based on elimination of the tetrahydropyranyl group from the poly(THPMI). Positive image patterns were obtained by chemical amplification of positive photoresist composed of poly(THPMI) and 4-morpholinophenyl diazonium trifluoromethanesulfonate used as an acid generator.

Structural change in poly(hexafluoro-1,3-butadiene) during heat treatment

Abstract The structural change in poly(hexafluoro-1,3-butadiene) that takes place during heat treatment was investigated by measuring its i.r. spectra. The polymer obtained from hexafluoro-1,3-butadiene (HFBD), produced by t-C4H9OCs initiation in toluene, showed excellent thermal properties, such as a high thermal decomposition temperature and a low thermal expansion coefficient. The thermal properties of poly(HFBD) were found to be similar to those of conventional thermosetting polymers, since the thermal expansion coefficient of poly(HFBD) decreased after the heating process. The absorption at ∼2970 cm−1, which was assigned to traces of initiator (t-C4H9), disappeared after heating at 200 or 400°C for 10 h. The absorption at ∼1710 cm−1, which was assigned to the CFCF bond in the main chain, and the peak at 1840 cm−1, both increased after heating at 400°C for 10 h. It is suggested that the chemical structure of the polymer was changed during the heating process. Furthermore, the radical species which was produced by cleavage of the bonds with heating at high temperatures might react with the CFCF bonds in the polymer chain to yield crosslinked species.

Block copolymerization ofN-phenylmaleimide onto poly(styrene) and poly(butadiene): synthesis and characterization

SummarySynthesis and characterization of novel block copolymers of N-phenylmaleimide (N-PMI) and styrene or butadiene are described. Block copolymerization of N-PMI to polystyrene or polybutadiene prepolymers was evidenced by GPC,1H NMR, and thin layer chromatographic analyses of the products.