摘要:

AbstractThe reaction of dodecanethiol with 4‐nitrophenyl acetate in the presence of dodecyl derivatives of poly(4‐vinylpyridine) and poly(1‐vinyl‐2‐ethylimidazole) was studied at 30°C. It was found that at pH 9,48 the reaction is completed after a few seconds in the presence of polymeric micelles with a content of dodecyl groups>22 mole‐%, and that the second‐order rate constant amounts to 3,2·103l mol−1s−1, which is ca. 150 times higher than that obtained in the absence of the polymer. The reaction rate increases with the content of dodecyl groups in the polymer and the maxima appear at 20 to 30 mole‐%. Polymers substituted with hexyl or ethyl groups instead of dodecyl groups, showed to be virtually ineffective. Obviously, the hydrophobic environment of the polymer activates

ISSN:0025-116X    

DOI:10.1002/macp.1977.021780601

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractCopolymers from styrene and 1‐vinylimidazoles (4a–f), form low spin adducts with iron(II) porphyrins and iron(III) porphyrins, when the content of imidazolyl groups in the polymer is ten mole percent or more. With polymers having a content of imidazolyl groups of less then one mole percent, only high spin adducts are observed. With terpolymers, in which the porphyrin is covalently bound to the copolymer the same phenomenon is observed. Only the high spin Fe(II) porphyrin adducts in the solid state adsorb molecular oxygen like cobalt(II) porphyrins under the same conditions. Adsorptions and desorptions of oxygen are much slower in the cases of iron(II) porphyrins than with the cobalt(II) porphyrins. Electronic and ESR spectra as well as susceptibility measurements were used to characterize the reported spin sta

ISSN:0025-116X    

DOI:10.1002/macp.1977.021780602

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractThe effect of alkali metal chlorides and 1‐substituted 3‐carbamoylpyridinium bromides (2a–d) on the metachromatic behavior of methylene blue (1) induced by poly(potassium styrenesulfonate) (PSS) and poly(potassium vinyl sulfate) (PVS) was investigated spectrophotometrically. The size of hydrated ion and the hydrophobicity of substituent were significant factors for inorganic and organic salts, respectively. Effect of these salts on the metachromasy was characteristic of each polyanion used. A peculiar phenomenon that the metachromasy of the PSS‐1system was enhanced on addition of small amounts of 1‐dodecyl‐3‐carbamoylpyridinium bromide (2d)

ISSN:0025-116X    

DOI:10.1002/macp.1977.021780603

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractAB block copolymers with a polyvinyl block (polystyrene or polybutadiene) and a polypeptide block (poly(carbobenzoxy‐L‐lysine)) were prepared by the following method: at first the polyvinyl block was synthesized by anionic polymerization, then its living end was transformed into a primary amine function and it was used as a macromolecular initiator for the polymerization of theN‐carboxy anhydride (NCA) of an α‐amino acid. After fractionation, studies of the copolymers by IR spectroscopy and X‐ray diffraction showed, that they exhibit a lamellar structure in dioxane solution and in the dry state. In this lamellar structure the polypeptide chains, present in an α‐helix conformation, are arranged in an hexagonal array a

ISSN:0025-116X    

DOI:10.1002/macp.1977.021780604

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractPyridine and picoline initiated polymerizations of maleic anhydride were investigated in acetic anhydride. It was found that the electrical conductivity of the polymerizing mixture increases in the course of the reaction, and that the initial rate of polymerization increases with increasing monomer and pyridine concentrations, and its values, measured at different temperatures, show the apparent overall activation energy to be about 10 kcal/mol (41,87 kJ/mol). The rates of polymerization and the increase of specific conductivities of the reaction mixtures show the following order of initiator activity: γ‐picoline>β‐picoline>pyridine>α‐picoline. Therefore, the results of the kinetic and conductivity measurements suggest that the polymerization rate depends on the basicity of the i

ISSN:0025-116X    

DOI:10.1002/macp.1977.021780605

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

摘要:

Abstract2,2′‐Methylene‐bis(4‐methyl‐1,2‐phenylene) dimethacrylate (1) was reacted with an excess of 2,2′‐azoiso‐butyronitrile (mole ratio 1:15) highly diluted in boiling benzene. The reaction products were separated by column chromatography. It was found that the 1‐cyano‐1‐methylethyl radical induced the cyclization of1to yield the product of a head to tail addition (2) in 55% yield. In addition, the product of a head to head addition (3) was isolated in 4% yield. 35% of1reacted in the same way as it has already been observed as suppression of polymerization in the case ofp‐tolyl methacrylate to give the products4and5. The structures of the products were confirmed by elemental analyses, by IR‐UV‐,1H NMR‐ and mass‐spectra as well as by the determination of their relative molecular masses a

ISSN:0025-116X    

DOI:10.1002/macp.1977.021780606

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractBis(1,3‐pentadiynyl)mercury (3) polymerizes quantitatively in the solid‐state if irradiated with UV‐light or annealed at 100–200°C. The polymer shows resonant Raman frequencies at 1412, 1454, 2024, and 2070cm−1typical for polymers containing butadiynyl (diacetylene) groups. The intensity of IR peaks due to the monomer triple bonds at 2098 and 2220 cm−1decreases during polymerization and vanishes at completion. From experimental evidences it is inferred that the polymerization is lattice controlled and can be described, similar to the solid state polymerization of butadiynyl derivatives, by the formation of a ladder polymer of two strands of a poly(2‐butynediylidene) linked toget

ISSN:0025-116X    

DOI:10.1002/macp.1977.021780607

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractThe effect of the boric acid concentration on the color reaction between partially saponified poly(vinyl acetate), which is dissolvable in water, and iodine‐iodide was investigated. As the concentration of boric acid increased, the absorbance at λmax= 488 nm of the red‐violet complex, which is due to a long sequence of vinyl acetate units distributed along the polymer chain, increased gradually, reached a maximum, and then decreased from the point in which the absorbance at λmax= 656nm of the blue complex, based on the vinyl alcohol units in the polymer, was observed. The color complex in an excess of boric acid transferred from red‐violet to red‐tinged blue with time. From the color change, the molar absorption coefficient at λmax= 656 nm for the iodine molecule in the blue complex was found to be 3,92.104

ISSN:0025-116X    

DOI:10.1002/macp.1977.021780608

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractThe pendant vinyl groups of reactive microgels prepared from 1,4‐divinylbenzene or divinylbenzene mixture were converted into hydroxyl groups by hydroboration with diborane. This reagent enters very fast into the network of the microgels and reacts with all vinyl group

ISSN:0025-116X    

DOI:10.1002/macp.1977.021780609

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

摘要:

Abstract1,4‐Polybutadiene was partially hydrobrominated in the presence of AlBr3. A Grignard‐Wurtz‐reaction with phenylmagnesium bromide resulted in an exchange of the bromine atoms for phenyl groups. The polymers were degraded in an olefin metathesis reaction with 4‐octene using a WCl6/Sn(CH3)4catalyst. The low molecular degradation products with bromine or phenyl substituents, resp., were separated by gas chromatography and identified by mass spect

ISSN:0025-116X    

DOI:10.1002/macp.1977.021780610

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY