摘要:

AbstractAromatischeo‐Diamine (1) und Propinal reagieren im Molverhältnis 1:2 zu 3,3′‐(1,2‐Arylen‐1,2‐diimino)dipropenalen (2). Die Umsetzung der Diamine1mit Propinal im Mengenverhältnis 1:1 nach verschiedenen Methoden führt zu niedermolekularen symmetrischen und asymmetrischen Tetraaza[14]annulen‐Derivaten (4). Zahlreiche Metallkomplexe (3und5) wurden aus den Verbindungen2bzw.4, dargestellt. Die Produkte wurden durch IR‐, Elektronen‐ und Massenspek

ISSN:0025-116X    

DOI:10.1002/macp.1975.021761001

出版商:Hüthig&Wepf Verlag    

年代:1975

数据来源: WILEY

摘要:

AbstractS‐Hexadecyl,S‐dodecyl,S‐decyl, andS‐octyl esters of thioalanine (1e, 1d, 1c, and1b) were prepared and reacted at a concentration range of 2,5·10−3to 1·10−1mol/l in water with pyridine as a base catalyst to give the cyclic dimer of alanine, 3,6‐dimethyl‐2,5‐piperazinedione (2). The yields of2from1eand1dwere similar within this concentration range, whereas the yield of2from1brapidly decreased in the concentration range from 1·10−1to 1·10−2mol/l, and no dimer2was obtained at 2,5·10−3and 5·10−3mol/l. These results support the proposed micellar mechanism in the condensation of thi

ISSN:0025-116X    

DOI:10.1002/macp.1975.021761002

出版商:Hüthig&Wepf Verlag    

年代:1975

数据来源: WILEY

摘要:

AbstractThe condensation reaction of thioalanineS‐dodecyl ester (1c) was carried out in several organic solvents, or in their mixtures with water. In acetone, benzene, chloroform, or hexane, no cyclic dimer of alanine, 3,6‐dimethyl‐2,5‐piperazinedione (2) and in the water/organic solvent mixtures only low yields of2were obtained, contrary to the good yields which resulted in water alone. In the condensation reaction of thioalanineS‐octyl ester (1b) obvious salt effects were observed, especially w

ISSN:0025-116X    

DOI:10.1002/macp.1975.021761003

出版商:Hüthig&Wepf Verlag    

年代:1975

数据来源: WILEY

摘要:

AbstractThe cationic copolymerization of 1,3‐dioxolane (1) with 5‐methyl‐2,3‐dihydro‐2‐furanone (2) which has two functional groups, a carbon‐carbon double bond and a lactone ring, was carried out with three triethyloxonium salts (Et3O+Y−, Y−: BF −4, FeCl −4and SbCl −6), with the boron trifluoride ethyl ether complex, and with tin tetrachloride in nitrobenzene, dichloromethane, and toluene at 0°C. On the basis of the NMR analysis of the microstructure of the copolymer, it was revealed that the growing species of1attacked exclusively the carbon‐carbon double bond of2in the cross‐propagation from1to2, regardless of the solvents and initiators used, except when triethyloxonium hexachloroantimonate was used as initiator. With the latter initiator, the ring opening reaction of2by the attack of the growing species of1occurred competitively with the usual vinyl addition, although the latter mode of reaction was predominant. The ring opening reaction of2with this initiator is probably caused by some specific interaction

ISSN:0025-116X    

DOI:10.1002/macp.1975.021761004

出版商:Hüthig&Wepf Verlag    

年代:1975

数据来源: WILEY

摘要:

AbstractAbsorption spectra were measured for poly(N‐vinylcarbazole) (PNVC), fractionated by means of the gel‐permeation chromatographic technique. The intensities of the UV absorption bands of the carbazolyl group diminished with increasing molecular weight of the polymer from 1200 to ca. 104, and were constant when the molecular weight was higher than 104. The diminution of the absorption intensities was regarded as a hypochromism, and the hypochromism was discussed with respect to the local structure of PNVC in solut

ISSN:0025-116X    

DOI:10.1002/macp.1975.021761005

出版商:Hüthig&Wepf Verlag    

年代:1975

数据来源: WILEY

摘要:

AbstractThe saponification reaction of bis(2‐hydroxyethyl) terephthalate (3) and sodium 3,5‐bis(2‐hydroxyethoxycarbonyl)benzenesulfonate (6) was followed under pH‐stat conditions in the alkaline pH range (pH 8 to 10 at 50 to 80°C) to determine the consecutive reaction rate constants for the hydrolysis of the diesters and the intermediate monoesters. The observed overall reaction rate constants were split into the individual rate constants for the hydrolysis catalyzed by the solvent, the OH−ions, the SO −3groups and the COO−groups (k0,kOH−,kSO −3,kCOO−, respectively). No intermolecular catalysis by either the sulfonato or the carboxylato groups and no “autocatalysis” by the solvent was found. The activation parameters for the hydrolysis of the corresponding esters of both acids are equal; for the diesters3and6: ΔH†= 73,7 (72,0) kJ mol−1[17,6 (17,2) kcal mol−1], ΔG†= 103,8 (104,7) kJ mol−1[24,8 (25,0) kcal mol−1], ΔS†= −89,6 (−97,6) J mol−1K−1[−21,4 (−23,3) cal mol−1K−1]; for the monoesters [terephthalic acid mono(2‐hydroxyethyl) ester and 5‐sodiumsulfonatoisophthalic acid mono(2‐hydroxyethyl) ester]: ΔH†= 80,4 (78,7) kJ mol−1[19,2 (18,8) kcal mol−1], ΔG†= 109,3 (109,7) kJ mol−1[26,1 (26,2) kcal mol−1], ΔS†= −86,3 (−93,0) J mol−1K−1[−20,6 (−22,2) cal mol−1K−1]. It is concluded that disorders in the fine structure of polyester fibers modified with sulfonato group containing comonomers may primari

ISSN:0025-116X    

DOI:10.1002/macp.1975.021761006

出版商:Hüthig&Wepf Verlag    

年代:1975

数据来源: WILEY

摘要:

AbstractCopolymerizations of (−)‐ and (±)‐menthyl acrylates were carried out and the optical rotation and the optical density ratio,D1372/D1235, which was an index of stereoregularity, were determined. The optical rotation of radically obtained poly[(−)‐menthyl acrylates] were higher and the optical density ratios were lower than those of anionically obtained polymers. The optical density ratios of the anionically obtained copolymers of (−)‐and (±)‐menthyl acrylates descreased with the decrease of (−)‐monomer content in the starting monomers, indicating the decrease in the isotacticity of the copolymers. Thus, the asymmetric effects of optically active menthyl groups on the main chain configurations in anionic polymeriza

ISSN:0025-116X    

DOI:10.1002/macp.1975.021761007

出版商:Hüthig&Wepf Verlag    

年代:1975

数据来源: WILEY

摘要:

AbstractThe polymerization of acrylamide in aqueous media, initiated by the acidified potassium permanganate/thioglycolic acid (1) redox pair was studied at 30±0,1°C in an inert atmosphere of dry and oxygen‐free nitrogen. The initial rate of polymerization was found to be proportional to nearly the first power of potassium permanganate concentration within the range of 2,0.10−3to 6,0.10−3moll−1. The rate was also found to be proportional to the first power of [acrylamide] in the range of 8,0.10−2to 10,0.10−2moll−1. The rate of polymerization appears to be independent of thioglycolic acid (1) concentration in the range of 1,0.10−2to 1,2.10−2moll−1. At still higher concentrations, however, the amount of1depresses the rate and maximum conversion. An excess of sulphuric acid was found to affect the rate of polymerization to a slight extent and a deficiency of the acid makes the reaction to stop at an early stage, during the range studied. This indicates, therefore, the presence of an optimum concentration of H2SO4for the smooth initiation of polymerization.A study on the effect of salts reveals that KCl and NH4Cl lower the initial rate of polymerization, whereas the reverse is true for MnSO4.H2O and Na2C2O4. The water‐miscible aliphatic alcohols e.g. CH3OH, C2H5OH, (CH3)2CHOH, and C4H9OH were found to depress the e

ISSN:0025-116X    

DOI:10.1002/macp.1975.021761008

出版商:Hüthig&Wepf Verlag    

年代:1975

数据来源: WILEY

摘要:

AbstractHydrolyses of amylose and sucrose in the presence of poly(vinyl alcohol‐co‐vinylsulfonic acid) were investigated. The hydrolysis rate of amylose was found to follow the Michaelis‐Menten type kinetics, whereas the hydrolysis of sucrose proceeded according to second‐order kinetics. The process of complex formation was characterized by remarkable decreases in enthalpy and entropy, and the enthalpy of activation for the decomposition of the complex to products was larger than that of the sulfuric acid catalyzed system. The hydrolysis of amylose was competitively inhibited by poly(vinyl alcohol), whereas it was not by sorbitol.Die Hydrolyse von Amylose und Rohrzucker wurde in Gegenwart von Copolymeren aus Vinylalkohol und Vinylsulfonsäure untersucht. Die Hydrolysegeschwindigkeit von Amylose folgt dabei der Kinetik nach Michaelis‐Menten, während die Hydrolyse von Rohrzucker nach zweiter Ordnung verläuft. Die Bildung des Komplexes aus den Copolymeren und Amylose geschieht unter beträchtlicher Abnahme von Enthalpie und Entropie. Die Aktivierungsenthalpie beim Zerfall des Komplexes in die Reaktionsprodukte ist größer als bei der mit Schwefelsäure katalysierten Reaktion. Die durch die Copolymeren katalysierte Hydrolyse von Amylose wird durch Polyvinylalkohol gehemmt, jedoch ni

ISSN:0025-116X    

DOI:10.1002/macp.1975.021761009

出版商:Hüthig&Wepf Verlag    

年代:1975

数据来源: WILEY

摘要:

AbstractDie Bromierung von 2‐(2‐Hydroxy‐5‐methylbenzyl)‐4,6‐dimethylphenol (1) und 2‐[2‐Hydroxy‐3‐(2‐hydroxy‐5‐methylbenzyl)‐5‐methylbenzyl]‐4,6‐dimethylphenol (2a) wurde in Eisessig bei 22°C untersucht. Die Reaktion läßt sich für [Br2]0= 1,4·10−3bis 6,0·10−3mol dm + und Konzentrationen der phenolischen Verbindungen [P]0zwischen 1,1·10−3und 5,5·10−3mol dm−3durch das folgende Geschwindigkeitsgesetz beschreiben:\documentclass{article}\pagestyle{empty}\begin{document}$$ v = - \frac{{{\rm d}[{\rm Br}_2 ]}}{{{\rm d}t}} = k_2 \cdot [{\rm P}] \cdot [{\rm Br}_2 ] + k_3 \cdot [{\rm P}] \cdot [{\rm Br}_2 ]^2$$\end{document}Während die gebildete Bromverbindung keinen Einfluß auf die Reaktionsgeschwindigkeit hat, verlangsamt der entstehende Bromwasserstoff die Reaktion. Die Bromierung ist trotzdem zur Bestimmung der Reaktionsfähigkeit von Phenolen und phenolischen Mehrkernverbindungen gut geeignet, da die Reaktion leicht durch Messung der Absorption des Broms bei 450 nm verfolgt werden kann. Zur Auswertung wurde dabei für kleine Umsätze (15%) ein Geschwindigkeitsgesetz 2. Ordnung zugrunde gelegt und die formale Geschwindigkeit

ISSN:0025-116X    

DOI:10.1002/macp.1975.021761010

出版商:Hüthig&Wepf Verlag    

年代:1975

数据来源: WILEY