摘要:

AbstractPoly(2‐vinylpyridine 1‐oxide) (3), poly(4‐vinylpyridine 1‐oxide) (4), and the dimeric analogue 2,2′‐trimethylenedipyridine 1‐oxide (2) form metal complexes with chlorides of copper(II), zinc, mercury(II), iron(III), cobalt(II), and nickel(II) salts. Due to steric reasons4forms two series (type6and7) of complexes by intramolecular or intermolecular crosslinking in which the ratio NO/metal is 2:1 (type6) or 1:1 (type7), whereas3and its model compound2can form only intramolecular 2:1 compl

ISSN:0025-116X    

DOI:10.1002/macp.1976.021770201

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractOn a montré qu'il est possible de synthétiser des copolymères greffés à greffons cristallisables présentant une bonne homogénéité en composition et en masse moléculaire. On a procédé par réaction de transestérification entre la fonction alcoolate de potassium terminale d'un polyoxyéthylène (lui‐même obtenu par polymérisation de l'oxiranne amorcée par du diphénylméthylpotassium) et les fonctions ester portées par un poly(méthacrylate de propyle) (ou de butyle). On a opéré en solution dans le toluène, à 110°C, dans un appareillage scellé sous vide.Pour caractériser les produits, on a utilisé conjointement l'ultracentrifugation, le fractionnementKössler‐Polǎček, la résonance magnétique nucléaire, la pyrolyse éclair combinée avec la chromatographie en phase gazeuse,

ISSN:0025-116X    

DOI:10.1002/macp.1976.021770202

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractThe coordination‐addition mechanism in the polymerization of a vinyl ketone initiated with alkylzinc was elucidated by use of model compounds for the growing chain end and for the monomer. The formation of a 1:1 complex between the zinc compound and the vinyl ketone in hydrocarbon solvents was concluded from the UV spectra of the binary system. In tetrahydrofuran or dioxane little evidence was obtainable for complex formation. Cryoscopic data of the binary system in hydrocarbons and in cyclic ethers were found to be in agreement with the conclusion obtained from the UV data. The results of the kinetic studies of model reactions are interpreted in terms of a coordination‐addition mechanism, which was derived taking all the spectroscopic and cryoscopic data into considerat

ISSN:0025-116X    

DOI:10.1002/macp.1976.021770203

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractDurch Reaktion von 4,5,9,10‐Pyrendichinon mit verschiedenen aromatischen Dialdehyden wurden neuartige Polyoxazole synthetisiert. Ihre Struktur wurde durch Vergleich ihrer IR‐Spektren mit denjenigen von entsprechend aufgebauten niedermolekularen Modellsubstanzen bestätigt. Die Thermostabilität der Polymeren wurde unter

ISSN:0025-116X    

DOI:10.1002/macp.1976.021770204

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractLa fixation de tyrosine, par sa fonction phénol, sur des molécules α,ω‐difonctionnelles, a été étudiée. Deux méthodes ont été utilisées: la première consiste à fixer une molécule de tyrosine à chaque extrémité d'un diisocyanate par l'intermédiaire d'une fonction carbamate; la deuxième demande la préparation d'un dimère de la tyrosine permettant la formation d'un polymère par condensation sur la mol

ISSN:0025-116X    

DOI:10.1002/macp.1976.021770205

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractThe heterogeneous hydrolysis of fibrous celluloses in the presence of poly(vinyl alcohol‐co‐vinylsulfonic acid) as catalyst was investigated. In this case, the rate acceleration, compared with the sulfuric acid catalysed reaction, which was clearly observed for the homogeneous hydrolysis of dextrin, became smaller with increasing density of the fine structure of the substrate. This decrease in the rate acceleration is presumed to be a result of the limited penetration of the copolymer molecules into the amorphous region of the fiber because of their larger molecular weig

ISSN:0025-116X    

DOI:10.1002/macp.1976.021770206

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractMethyl methacrylate oligomers were prepared through anionic oligomerization initiated with sodium methoxide. Pure n‐mers1a–cup to the trimer1cwere isolated from the reaction products. The1H NMR spectra of these pure n‐mers were studied in various organic solvents. An a priori assignment of these resonance patterns was attained and the fine structures of the spectra, were analyzed in relation to the stereospecific conformation of the individual molecules, taking into account the structural end group effects and the characteristics of the geminal methylene proton signals of this series of model compounds. The results obtained for both of the stereo‐isomers of the dimer molecules1bwere extended for analyzing the more complicated spectra of the trimer molecules1c. The magnitudes of the coupling constant for the geminal methylene protons of these n‐mers were determined as follows: −9,0 Hz for the 1‐mer1a, −14,0 Hz for the dimers1band −14,5 Hz for the trimers1c. These results are compared with those obtained for similar geminal coupling of central methylene protons ofmesodimethyl 2,4‐dimethylglutarate (−13,1 Hz) and ofisotacticpoly(methyl meth

ISSN:0025-116X    

DOI:10.1002/macp.1976.021770207

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractDurch Reaktion von 2,2′‐Dichlor‐2,2′‐azopropan (1) mit 2‐Brommagnesiummalonsäure‐diäthylester (2) wurde der 2,2′‐Azo(2‐methyl‐1,1‐propandicarbonsäure‐diäthylester) (3) in 52% Ausbeute dargestellt. Durch Verseifen von3erhielt man in 75% Ausbeute die entsprechende wasserlösliche 2,2′‐Azo(2‐methyl‐1,1‐propandicarbonsäure) (4), die bei 160°C zur ebenfalls wasserlöslichen 2,2′‐Azo(2‐methyl‐1‐propandicarbonsäure) decarboxylierte. Die Kinetik der Thermolyse von3und5wurde in Äthylbenzol bei 180°C bestimmt.4und

ISSN:0025-116X    

DOI:10.1002/macp.1976.021770208

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractThe free radical copolymerization of butadiene and vinylferrocene was studied at 60°C in 1,4‐dioxane. Copolymerization occurs readily to give low molecular weight random copolymers. The reactivity ratios arer1(butadiene) = 3,5±0,5 andr2(vinylferrocene) = 0,30±0,10 and theQandevalues for vinylferrocene are 0,68 and −1,05, respectively. The copolymers are shown to contain a paramagnetic species which is identified as a high spin Fe(III) c

ISSN:0025-116X    

DOI:10.1002/macp.1976.021770209

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractThe possibility of determination of the propagation and termination rate constantskpandkt, resp., as well as their ratioskp/ktandkp/k t1/2in homogeneous radical polymerization is shown using the capacity flow method. A theoretical analysis is carried out and relatively simple equations are introduced. The essential point is that the life time of the growing polymer chain is obtained graphically from the residence time of the reactants in the reactor vessel, which is a given quantity. As an experimental example the polymerization of methyl methacrylate initiated by benzoyl peroxide in benzene is investigated in a flow reactor with perfect mixing at 80°C. It is characteristic that the process can be followed by means usually applied for studying slow reactions. The degree of conversion is measured turbidimetrically and gravimetrically, whereas the initiation rate is analysed iodometrically. Thus, through a numerical linear approximation by the method of least squareskp/kt= (2,28±0,45)·10−5,kp/k t1/2= (1,50±0,22). 10−1are found from the experimental data, and hencekp= (9,95±0,83)·102l mol−1s−1andkt= (4,36±0,49)·107l m

ISSN:0025-116X    

DOI:10.1002/macp.1976.021770210

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY