POLY [N-(4-PYRIDINIUM DICHROMATE)-P-STYRENE SULPHONAMIDE] AS AN EFFICIENT REAGENT FOR OXIDATION OF ALCOHOLS

POLY [N-(4-PYRIDINIUM DICHROMATE)-P-STYRENE SULPHONAMIDE] is readily prepared. It is a stable, mild, and efficient oxidizing reagent that can be used for oxidation of different alcohols to their corresponding carbonyl compounds in approtic solvents. This polymer can be synthesized from the reaction between poly [N-(4-pyridyl)-p-styrene sulphonamide] and CrO ₃ in a minimum amount of water. The latter polymer was prepared by free radical polymerization of [N-(4-pyridyl)-p-styrene sulphonamide] by using azobis(isobutyronitrile) (AIBN) as an initiator. N-(4-pyridyl)-p-styrene sulphonamide was synthesized from commercial 4-vinyl benzene sulphonic acid sodium salt and 4-amino pyridine. POLY [N-(4-PYRIDINIUM DICHROMATE)-P-STYRENE SULPHONAMIDE] can oxidize both aliphatic and aromatic alcohols in good yields at a temperature of 38°C and in CH ₂ Cl ₂ as solvent. One advantage in using this reagent is the mild condition of the reaction system. The synthesized compounds including polymeric reagent and carbonyl compounds were identified by HNMR and IR spectroscopy.     

A VERSATILE AND REGIOSELECTIVE SYNTHESIS OF VICINAL AZIDOALCOHOLS USING CROSS-LINKED POLY（4-VINYLPYRIDINE） SUPPORTED AZIDE ION UNDER SOLVENT-FREE CONDITIONS

A new polymeric reagent, cross-linked poly（4-vinylpyridine） supported azide ion, [P4-VP]N3, was introduced as polymeric reagents for efficient and regioselective conversion of epoxides to azidohydrins in the presence of cross-linked poly（4-vinylpyridine） supported sulfuric acid, [P4-VP]H2SO4, as a solid proton source and as catalyst under solvent-free conditions. The advantages of this polymeric reagent over some of those reported in the literature are easy work-up procedure and regeneration of the reagent.     

A Convenient Oxidation of 5‐Substituted Pyrazol‐3(2H)‐Ones Into Methyl 2‐Alkynoates Using Poly[4‐(Diacetoxyiodo)Styrene]

An operationally simple oxidation of 5‐substituted pyrazol‐3(2H)‐ones to the corresponding methyl‐2‐alkynoates in good yields with a mediated poly[4‐(diacetoxyiodo)styrene] system in methanol and acetonitrile at room temperature was carried out. The polymeric reagent can be regenerated and reused as an environmentally benign reagent.     

A novel synthesis of linear high-molecular-weight poly(4-vinylphenol) and poly[styrene-co-(4-vinylphenol)]

A novel synthesis of linear high-molecular-weight poly(4-vinylphenol) (PVPh) and poly[styrene-co-(4-vinylphenol)] (STVPh, 2 ) via demethylation reaction is developed. The parent polymers, poly(4-methoxystyrene) and poly[styrene-co-(4-methoxystyrene)] produced by free-radical polymerization, are converted to PVPh and STVPh ( 2 ), respectively, by being treated with trimethylsilyl iodide (TMSI) at room temperature. Both ¹H NMR and ¹³C NMR data show that methoxy is completely cleaved and converted to hydroxy after hydrolysis without crosslinking and other side reactions. In addition, size-exclusion chromatography data show that no chain scission occurs during group conversion.     

Synthesis of poly(4-vinylbenzocyclobutene) and its reaction with dienophiles

4-Vinylbenzocyclobutene ( 1 ) was prepared by the nickel-catalyzed coupling reaction of 4-bromobenzocyclobutene with vinylbromide in 70% yield. Radical homopolymerization of 1 at 60°C for 24 h afforded poly(4 vinylbenzocyclobutene) [poly( 1 )] in 89% yield and radical copolymerizations of 1 with styrene (St) or methyl methacrylate (MMA) were carried out to obtain the corresponding copolymers. The Q = 1.07, e = 0.046. As a model reaction of the polymer reaction of the polymer reaction of poly( 1 ) and poly(4-vinylbenzocyclobutene-co-styrene) [copoly( 1 -St)] with dienophiles, the Diels-Alder reaction of benzocyclobutene with N-phenylmaleimide (MI) or maleic anhydride (MANH) was carried out to determine the optimum reaction conditions. Under the optimum condition, the Diels-Alder reaction of poly( 1 ) and copoly( 1 -St) with MI and MANH in the presence of 4-tert-butyl-catechol as an inhibitor were carried out to yield the corresponding polymers in good yields. The properties (solubilities, T_g, and temperature of 10% weight loss) of the products obtained from the polymer reaction were different from these of poly( 1 ). © 1995 John Wiley & Sons, Inc.     

Synthesis of vinyl graft copolymers of poly(hexamethylene adipamide) and poly(m-phenylene isophthalamide)

Nylon 66 [poly(hexamethylene adipamide)] and Nomex [poly(m-phenylene isophthalamide)] were metalated by using solutions of sodium in liquid ammonia. Metalation of the Nomex polymer was also carried out by using sodium naphthalene in tetrahydrofuran. The metalated polymers were then reacted with acrylonitrile monomer to yield the corresponding anionic graft copolymers. The heterogeneous nature of these reactions is discussed in relation to the structure of the graft copolymers.     

Kinetics and mechanism of chromium(III) catalyzed oxidation of 1,10-phenanthroline by alkaline permanganate

The kinetics of chromium(III) catalyzed oxidation of 1,10-phenanthroline by permanganate in alkaline medium at a constant ionic strength has been studied spectrophotometrically. The reaction between permanganate and 1,10-phenanthroline in alkaline medium exhibits 4:1 stoichiometry (KMnO₄:1,10-phenanthroline). The reaction shows first order dependence on [permanganate] and [chromium(III)] and less than unit order dependence in 1,10-phenanthroline, zero order in alkali concentrations. The results suggest the formation of a complex between the 1,10-phenanthroline and the chromium(III) which reacts further with one mole of permanganate species in the rate-determining step, resulting in the formation of a free radical, which again reacts with three moles of permangante species in a subsequent fast step to yield the products. The reaction constants involved in the mechanism were evaluated. The activation parameters were computed with respect to the slow step of the mechanism.This revised version was published online in December 2005 with corrections to the Cover Date.     

Kinetic, mechanistic and spectral investigation of ruthenium (III)-catalysed oxidation of atenolol by alkaline permanganate (stopped-flow technique)

Kinetics of ruthenium (III) catalyzed oxidation of atenolol by permanganate in alkaline medium at constant ionic strength of 0.30 mol dm³ has been studied spectrophotometrically using a rapid kinetic accessory. Reaction between permanganate and atenolol in alkaline medium exhibits 1 : 8 stoichiometry (atenolol : KMnO₄). The reaction shows first-order dependence on [permanganate] and [ruthenium (III)] and apparently less than unit order on both atenolol and alkali concentrations. Reaction rate decreases with increase in ionic strength and increases with decreasing dielectric constant of the medium. Initial addition of reaction products does not affect the rate significantly. A mechanism involving the formation of a complex between catalyst and substrate has been proposed. The active species of ruthenium (III) is understood as [Ru(H₂O)₅OH]₂₊. The reaction constants involved in the different steps of mechanism are calculated. Activation parameters with respect to the slow step of the mechanism are computed and discussed and thermodynamic quantities are also calculated.     

Phase behavior and interactions in blends of poly[(butylene adipate)-co-poly(butylene terephthalate)] copolyester with poly(4-vinyl phenol)

Miscibility with a linear T _g–composition relationship was proven for blend of poly(butylene adipate-co-butylene terephthalate) [P(BA-co-BT)] with poly(4-vinyl phenol) (PVPh). In comparison to the blends of PBA/PVPh and poly(butylene terephthalate) (PBT)/PVPh, the Kwei’s T _g model fitting on data for the P(BA-co-BT)/PVPh blend yields a q value between those for the PBA/PVPh and PBT/PVPh blends. The q values suggest that the interaction strength in the P(BA-co-BT)/PVPh blend is not as strong as that in the PBT/PVPh blend. Upon mixing the PVPh into the immiscible blend of PBA and PBT, the ternary PBA/PBT/PVPh blends only exhibits partial miscibility. Full-scale ternary miscibility in whole compositions is not possible owing to the significant ∆χ effect (χ _ij  – χ _ik ). The wavenumber shifts of the hydroxyl IR absorbance band indicates that the H-bonding strength is in decreasing order—PBT/PVPh > P(BA-co-BT)/PVPh > PBA/PVPh—and shows that the BA segment in the copolymer tends to defray interactions between P(BA-co-BT) and PVPh in blends.     

Reactivity investigations of some chosen peroxo-vanadium(V), manganese(III) and chromium(VI) compounds

An interpretative account of the results of reactions in aqueous medium of a highly peroxygenated vanadium(V) complex, K [V(O_{2 3}]·3H₂O, with different organic and inorganic substrates is presented. The reactions were monitored by solution EPR spectroscopy and isolation of products at different stages of the reactions. Redox reactions between diperoxide, K[VO(O₂)₂(H₂O)] and VOSO₄ were conducted. The results of the investigation suggest that secondary oxygen exchange-reaction occurs which not only depends on but also utilises the intermediates in the primary reaction during diperoxovanadate-dependent oxidation of VOSO₄. In an interesting reactiontris(acetylacetonato)-manganese(III), Mn(acac)₃, on being reacted with a hydrogen peroxide adduct, KF·H₂O₂, and bpy and phen afforded crystalline [Mn(acac)₂(bpy)] and [Mn(acac)₂(phen)], respectively. The X-ray structural analysis of [Mn(acac)₂(phen)] showed that the compound crystallised in orthorhombic space groupPbcn. The structure consists of a pseudooctahedral Mn(II) ion being bound to two acac⁻(C₅H₅O ₂ ⁻ ) and a phen ligand with the molecule lying on two-fold axis. Reactivity profiles of two new chromium(VI) reagents viz., pyridinium fluorochromate, C₅H₅NH[CrO₃F] (PFC), and quinolinium fluorochromate C₉H₇NH [CrO₃F] (QFC), have been presented. The compounds are capable of acting as both electron-transfer and oxygen-atom-transfer agents. The X-ray analysis of PFC crystals reveals that the compound crystallises in the orthorhombic space group CmcZ₁. The structure consists of discrete pyridinium cations and CrO₃ F anions with no significant hydrogen bonding. This results in total disorder of the pyridinium cation. The tetrahedral [CrO₃ F]⁻ ion lies on a crystallographic mirror plane.     

聚 (4-乙烯基吡啶硝酸盐)、硅硫酸和溴化铵催化氧化硫化物生成亚砜

 A new catalytic procedure for the chemoselective oxidation of sulfides to sulfoxides was studied. A variety of aliphatic and aromatic sulfides were subjected to sulfoxidation by combining poly(4-vinyl pyridinium nitrate), silica sulfuric acid (SiO₂-OSO₃H), and catalytic amounts of ammonium bromide in CH₂Cl₂ in the presence of a few drops of water at room temperature. Excellent yields were obtained.     

Synthesis of end‐functionalized poly(phenylacetylene)s with well‐characterized palladium catalysts

End‐functionalized poly(phenylacetylene)s were synthesized by the polymerization of phenylacetylene (PA) using the well‐defined palladium catalysts represented as [(dppf)PdBr(R)] {dppf = 1,1′‐bis(diphenylphosphino)ferrocene}. The Pd catalysts having a series of R groups such as o‐tolyl, mesityl, C(Ph)?CPh₂, C₆H₄‐o‐CH₂OH, C₆H₄‐p‐CN, and C₆H₄‐p‐NO₂ in conjunction with silver triflate polymerized PA to give end‐functionalized poly(PA)s bearing the corresponding R groups in high yields. The results of IR and NMR spectroscopies and MALDI‐TOF mass analyses proved the introduction of these R groups at one end of each polymer chain. The poly(PA) bearing a hydroxy end group was applied as a macroinitiator to the synthesis of a block copolymer composed of poly(PA) and poly(β‐propiolactone) moieties. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Syntheses of well-defined star-shaped poly(tetrahydrofuran) polyols by the ion-coupling method

The prepoly(tetrahydrofuran) [poly(THF)] capped with hydroxyl and tetrahydrothiophenium groups was prepared using tetrahydrothiophene to terminate the living cationic polymerization of THF initiated by BF₃·OEt₂ and epichlorohydrin (ECH) at low conversion. Well-defined star-shaped poly(THF) polyols were synthesized by an ion-coupling reaction of the prepoly(THF) with tri- or tetrafunctional benzenecarboxylates, respectively, and this process proceeded by precipitation when the solution of the prepolymer in THF was added to an aqueous solution containing an excess of the corresponding coupling reagent. GPC studies showed that all of the carboxylate groups of every coupling reagent molecule took part in the ion-coupling reaction simultanously. This was confirmed by IR spectra. Almost all of the prepolymers were coupled to form star polymers after repeating the precipitation four times. ¹H-NMR illustrated that both the star-shaped polymers and the prepolymers contained primary and secondary hydroxyl end groups. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 3403–3408, 1997     

Surface-enhanced raman scattering from poly(4-vinyl pyridine)

Surface-enhanced Raman scattering (SERS) has been observed for poly(4-vinyl pyridine) absorbed onto silver island films. Bands near 1219 and 1613 cm^?1, which are weak in normal Raman spectra of PVP, are strong in SERS spectra, and the band near 1020 cm^?1, which is the strongest band in the normal spectra, is relatively weak in SERS. The strongest bands in the SERS spectra all belong to the same symmetry species as α_ZZ, implying that the pyridine moieties are adsorbed through the nitrogen atoms with a vertical conformation. The ring breathing mode of the pyridine rings is observed near 1020 cm^?1, a frequency characteristic of pyridinium ions or coordinated pyridine, providing further evidence for adsorption through the nitrogen atoms. Silver catalyzed photooxidation, which can lead to the appearance of artifacts in SERS spectra, particularly of polymers, can be reduced by overcoating SERS samples with thin films of polymers such as poly(methyl methacrylate) that have low Raman scattering cross sections.     

Synthesis of functionalized linear poly(divinylbenzene). III. Synthesis of polymeric delocalized carbanion of poly(divinylbenzene) and its reactions

A polymeric delocalized carbanion of poly(divinylbenzene) [poly(DVB)] (2) was obtained by the proton abstraction with alkyllithium from the acidic methine moieties (H_A) of linear poly(DVB) (1) , which was prepared by the polymerization of DVB initiated by acetyl perchlorate. The formation of polyanion 2 was confirmed by UV–visible spectroscopy (λ_max = 630 nm) and the reaction with methyl iodide to give methylated poly(DVB). Delocalized polyanion 2 reacted with various electrophilic reagents in THF at 60°C, to yield poly(DVB) derivatives having pendant trimethylsilyl, vinyl, vinyloxyl, hydroxyl, and carboxyl groups. Proton abstraction with base and subsequent reactions with electrophiles were also studied with the linear unsaturated dimer of styrene (1,3-diphenyl-1-butene), as a model for poly(DVB) 1 .     

Cross-linked poly (4-vinylpyridine) supported azide ion as a versatile and recyclable polymeric reagent for synthesis of 1-substituted-1H-1,2,3,4-tetrazoles

Cross-linked poly (4-vinylpyridine) supported azide ion, [P₄-VP]N₃, is easily prepared and used as an efficient polymeric reagent for synthesis of 1-substituted-1H-1,2,3,4-tetrazoles via condensation reaction of azide ion, primary aromatic amines, and triethyl orthoformate in glacial acetic acid. After optimization of the reaction conditions, a wide variety of primary aromatic amines were also subjected to preparation of the corresponding 1-aryl-1 H-1,2,3,4- tetrazoles using [P₄-VP]N₃ under heterogeneous conditions. In this method, the reaction times were very short and the isolated yields were excellent (90–98 %). 1-Aryl-1H-1,2,3,4- tetrazole products were characterized by Fourier transform infrared (FT-IR) and some of them were also characterized by proton nuclear magnetic resonance (¹H NMR) spectroscopy, and physical properties were compared with the literature values of known compounds. The spent polymeric reagent were regenerated quantitatively and reused for several cycles without significant loss of their activity.     

Studies of polymer blends. I. Compatibility of poly(vinyl chloride) and poly(ethylene-co-vinyl acetate-co-sulfur dioxide)

Various methods of determining polymeric molecular compatibility were applied to blends of poly(vinyl chloride) (PVC) and poly(ethylene-co-vinyl acetate-co-sulfur dioxide) (E/VA/SO₂). In one series, where the E/VA/SO₂ had a mole composition of 72.7/18.5/8.8, true compatible blends were demonstrated by phase-contrast microscopy, torsion pendulum studies, and differential scanning calorimetry experiments for blends containing up to 40% E/VA/SO₂. These blends exhibited a single T_g whose compositional variation was found to follow the Fox expression. Experimental densities were slightly greater than predicted on assuming volume additivity. This observation implies better packing and a negative heat of mixing and thus is in harmony with a negative free energy of mixing and the observed molecular compatibility.     

Synthesis and properties of the ionomer diblock copolymer poly(4‐vinylbenzyl triethyl ammonium bromide)‐b‐polyisobutene

A new amphiphilic diblock copolymer containing an ionomer segment, poly[(4‐vinylbenzyl triethyl ammonium bromide)‐co‐(4‐methylstyrene)‐co‐(4‐bromomethylstyrene)]‐b‐polyisobutene [poly(4‐VBTEAB)‐b‐PIB], was synthesized by the chemical modification of poly(4‐methylstyrene)‐b‐polyisobutene [poly(4‐MSt)‐b‐PIB]. First, the 4‐methylstyrene moiety in poly(4‐MSt)‐b‐PIB was brominated with azobisisobutyronitrile as an initiator at 60 °C in CCl₄, and then the highly reactive benzyl bromide groups were ionized by a reaction with triethylamine in a toluene/isopropyl alcohol (80/20 v/v) mixture at about 85 °C to produce the ionomer diblock copolymer poly(4‐VBTEAB)‐b‐PIB. The solubility of the ionomer block copolymer was quite different from that of the corresponding poly[(4‐methylstyrene)‐co‐(4‐bromomethylstyrene)]‐b‐polyisobutene {poly[(4‐MSt)‐co‐(4‐BrMSt)]‐b‐PIB}. Transmission electron microscopy observations demonstrated that all three diblock copolymers had microphase‐separation structures in which polyisobutene (PIB) domains existed in the continuous phase of the poly(4‐methylstyrene) segment or its derivative segment matrix. Dynamic mechanical thermal analysis measurements showed that poly[(4‐MSt)‐co‐(4‐BrMSt)]‐b‐PIB had two glass‐transition temperatures (T_g's), ?56 °C for the PIB segment and 62 °C for the poly[(4‐MSt)‐co‐(4‐BrMSt)] domain, whereas poly(4‐VBTEAB)‐b‐PIB showed one T_g at ?8 °C of the PIB domain; T_g of the poly[(4‐vinylbenzyl triethyl ammonium bromide)‐co‐(4‐methylstyrene)‐co‐(4‐bromomethylstyrene)] domain was not observable because of the strong ionic interactions resulting in a higher T_g and a retention of modulus up to 124 °C. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2755–2764, 2003     

Determination of organic substances by oxidation with permanganate : XIX. Analysis of mixtures of malonic and oxalic acids and of malonic and formic acids

A method for the analysis of mixtures of malonic and oxalic and malonic and formic acids has been developed. The method is based on stepwise oxidation with excess permanganate in alkaline [Eqs. (1) and (3)] and acid [Eq. (2)] media.     

Synthesis and characterization of poly(4-vinyl,2′-carboxybensophenone)

The synthesis and characterization of poly(4-vinyl,2′-carboxybenzophenone) ion exchange resin is described. This resin displays a remarkably high capacity for Cu²⁺. Control of pH permits selective adsorption and estimation of Fe³⁺. This ion-exchanger is quite stable to loading acid washing cycles. © 1995 John Wiley & Sons, Inc.