ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Simultaneous determination of primary and secondary amino groups in polyamide with 1-fluoro-2,4-dinitrobenzene10th. report in the series: Synthetic Fibres in the Wool Industry, 9th. report: V. Rossbach, D. Nissen, G. Blankenburg, and H. Zahn, Wochenblatt für Papierfabrikation 101 (1973) 819. (1975)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 42 (1975), S. 1-20 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Zur chemischen Bestimmung der Aminoendgruppen in Polyamiden wird das Polymere in 2,2,2-Trifluoräthanol (TFÄ) mit 1-Fluor-2,4-dinitrobenzol (FDNB) umgesetzt. Das Nω-[2,4-Dinitrophenyl(1)]- (DNP-) Polyamid wird in Wasser von pH 3 ausgefällt, von anhaftendem Reagenz befreit, in TFÄ gelöst und bei λmax = 350 nm photometriert ( ε350: 17 300 [ 1000 cm2/mol]). Diese endgruppenspezifische Analysenmethode erlaubt eine Differenzierung in primäre und sekundäre Aminogruppen und deren Bestimmung nebeneinander, denn DNP-Derivate sekundärer Aminogruppen zeigen ein nach 390 nm verschobenes Absorptionsmaximum (ε390: 18 000 [1 000 cm2/mol]). Dieses Spektralverhalten wird mit Hilfe einer Zweikomponentenanalyse, die anhand von Messungen an dinitrophenylierten primären Aminen, sekundären Aminen und Polyamid-6- und -6,6-Oligomeren entwickelt wurde, quantitativ ausgewertet: \documentclass{article}\pagestyle{empty}\begin{document}$ \begin{array}{l} {\rm c}_1 = (7,49 \times {\rm E}_{350} - 3,62 \times {\rm E}_{390} ) \times 10^{ - 5} ; \\ {\rm c}_2 = (7,21 \times {\rm E}_{390} - 3,41 \times {\rm E}_{350} ) \times 10^{ - 5} ; \\ \end{array} $\end{document} (c1: Konzentration an primären Aminogruppen in mol/l; c2: Konzentration an sekundären Aminogruppen in moll; E350, E390: Extinktion bei 350 nm bzw. 390 nm).Die Variationskoeffizienten für die Bestimmungen betragen bei vier unmodifizierten und modifizierten Polyamid-6-Handelsfasern 2,7 bis 6,0%. Die nachweisbare Grenzkonzentration liegt bei 6 × 10 mol DNP-Aminogruppen/l TFÄ.Für die Umsetzung von FDNB mit Polyamid-6 und ε-Aminocapronsäure als Modell-substanz für das Polymere ergibt die kinetische Analyse mit der Eyring'schen „Theorie des aktivierten Komplexes“, daß das „Prinzip der gleichen Reaktivität“ für Polymeres und Monomeres erfüllt ist. Die Aktivierungsparameter für die Reaktion betragen: ΔH≠: 15.9 k 0,9 kcal/mol; ΔG≠: 22.9 ± 0.3 kcal/mol und ΔS≠: -22,1 ± 1,9 cal/Grad × mol.
    Notes: In order to determine chemically the amino end groups present in a polyamide, the polymer was treated with a solution of 1-fluoro-2,4-dinitrobenzene (FDNB) in 2,2,2-trifluoroethanol (TFE). The resulting Nω-[2,4-dinitrophenyl-(1)]-(DNP-) polyamide was precipitated in water at pH 3, washed free of excess reagent, redissolved in TFE, and the optical density of the solution measured at λmax = 350 nm (ε350: 17300 [1000 cm2/mole]). Both the primary and secondary amino groups could be simultaneously determined by this method, since the absorption maximum of dinitrophenylated secondary amino groups is shifted to 390 nm (ε390: 18000 [1000 cm2/mole]). Using this spectroscopic phenomenon a two-component analytical procedure was developed. With known concentrations of dinitrophenylated primary amines, secondary amines, and nylon-6 and nylon-6,6 oligomers, the following analytical equations were derived: \documentclass{article}\pagestyle{empty}\begin{document}$ \begin{array}{l} {\rm c}_1 = (7.49 \times {\rm D}_{350} - 3.62 \times {\rm D}_{390} ) \times 10^{ - 5} ; \\ {\rm c}_2 = (7.21 \times {\rm D}_{390} - 3.41 \times {\rm D}_{350} ) \times 10^{ - 5} ; \\ \end{array} $\end{document}〈\UEQN〉 \begin{array}{l} {\rm c}_1 = (7.49 \times {\rm D}_{350} - 3.62 \times {\rm D}_{390} ) \times 10^{ - 5} ; \\ {\rm c}_2 = (7.21 \times {\rm D}_{390} - 3.41 \times {\rm D}_{350} ) \times 10^{ - 5} ; \\ \end{array} $\end{document} (c1: concentration of primary amino groups in mole/l; c2: concentration of secondary amino groups in mole/l; D350, D390: optical density at 350 nm and 390 nm resp.).The coefficients of variation for four different commercially available nylon-6 fibres (unmodified and modified for dyeability) were in the range of 2.7 to 6.0%. The limiting concentration detectable was 6 × 10-7 mole DNP-amino groups/l TFE.A kinetic analysis was performed for the reaction of FDNB with nylon-6 and with a model compound, ε-aminocaproic acid. Using the “absolute rate theory of Eyring”, it was found that the polymer and monomer both fulfilled the “principle of equal reactivity”. The activation parameters for the reaction were: ΔH≠ : 15.9 ± 0.9 kcal/mole, ΔG≠: 22.9 ±0.3 kcal/mole, and ΔS≠: -22.1 ± 1.9 e.u./mole.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1975.050420101
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Determination of carboxyl endgroups and comonomers in poly(ethylene terephthalate) with hydrazineDedicated to Prof. Dr.-Ing. Habil. Clemens Sustmann on the occasion of his seventieth birthday. (1974)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 18 (1974), S. 1953-1968 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: On complete hydrazinolysis of poly(ethylene terephthalate), terephthalomonohydrazide is formed from carboxyl-end terephthaloyl residues in a quantity equivalent to the content of carboxyl endgroups in the polymer. The compound is separated from the reaction mixture by ion exchange and determined photometrically [epsiv;240 in 0.1 N HCl = 16,700 (1000 cm2/mole)]. A COOH determination carried out in this way is endgroup specific and, unlike titration, is not subject to interference by ionogenic fiber additives. Aromatic comonomers with acidic substituents (e.g., 5-sulfoisophthalic acid) in chemically modified, cationically dyeable poly(ethylene terephthalate) are determined simultaneously with the carboxyl endgroups by the same analytical method. In this case, the terephthalamonohydrazide and 5-sulfoisophthalodihydrazide are separated by ion exchange, and the difference in their spectral behavior is used for quantitative determination with the aid of a two-component analysis: \documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{l} c_1 {\rm = (6}{\rm .21 }D_{240} {\rm - 1}{\rm .04 }D_{212} ){\rm } \times {\rm 10}^{{\rm - 5}} {\rm mole/l}{\rm .} \\ c_2 {\rm = (2}{\rm .62 }D_{212} {\rm - 0}{\rm .51 }D_{240} ){\rm } \times {\rm 10}^{{\rm - 5}} {\rm mole/l} \\ \end{array} $$\end{document} where c1c2 = concentration of terephthalomonohydrazide and 5-sulfoisophthalodihydrazide, respectively; and D240 D212 = optical density at 240 and 212 nm, respectively. The content of carboxyl endgroups in polyether esters poly(p-(2-ethyleneoxy)-benzoate), is determined on the basis of the p-(β-hydroxyethoxy)benzoic acid [epsiv;258 in 0.1 N HCl = 16,100 (1000 cm2/mole)] liberated from carboxyl-end monomer units by hydrazinolysis. For copolyether esters with p-(β-hydroxyethoxy)benzoic acid as a comonomer, the contents of carboxyl-end terephthalic acid and p-(β-hydroxyethoxy)benzoic acid are determined simultaneously with the acid of a spectrophotometric twocomponent analysis: \documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{l} c_1 {\rm = (7}{\rm .65 }D_{240} {\rm - 3}{\rm .27 }D_{258} ){\rm } \times {\rm 10}^{{\rm - 5}} {\rm mole/l}{\rm .} \\ c_2 {\rm = (7}{\rm .91 }D_{258} {\rm - 3}{\rm .49 }D_{240} ){\rm } \times {\rm 10}^{{\rm - 5}} {\rm mole/l.} \\ \end{array} $$\end{document} where c2, c2 = concentration of terephthalomonohydrazide and p-(β-hydroxyethoxy)-benzoic acid, respectively; and D240, D258 = optical density at 240 and 258 nm, respectively.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1974.070180705
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Polydepsipeptides, 4Part 3: R. T. Ingwall and M. Goodman, Macromolecules 7, 598 (1974). Synthesis of the alternating Polydepsipeptides Poly(Ala-Lac) and Poly(Val-Lac)Abbreviations employed in this article are those recommended by the IUPAC-IUB Commission on Biochemical Nomenclature. All amino and α-hydroxy acids referred to in the text are of the L- or - S-configuration, respectively; Lac = s-lactic acid.Dedicated to Professor Herman F. Mark on the occasion of his 80th birthday (1975)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 1 (1975), S. 23-53 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Polydepsipeptide (Polypeptolide) mit der Wiederholungeinheit Alanyl-lactyl und Valyl-lactyl wurden hergestellt durch thermische Polymerisation der Tetradepsipeptide L-Alanyl-L-lactyl-L-alanyl-L-milchsäure- und L-Valyl-L-lactyl-L-valyl-L-milchsäure-pentachlorphenylester-trifluoracetat. Esterbindungen von Zweierfragmenten wurden mittels N,N′-Carbonyl-diimidazol geknüpft, Peptidbindungen zwischen Zweierfragmenten durch Kupplung einer N-Boc-geschützten Peptolidsäure an ein C-benzylgeschütztes Peptolidamin in Gegenwart on N,N′-Dicyclohexylcarbodiimid. Alternativ dazu wurde eine N-Boc-geschützte Peptolidsäure als gemischtes Anhydrid von Isobutancarbonsäure mit der Aminogruppe des entsprechenden Peptolid-pentachlorphenylesters umgesetzt. Dies war möglich auf Grund der untrschiedlichen Aminolysegeschwindigkeiten des gemischten Carbonsäureanhydrids und des Pentachlorphenylesters. Für die thermische Polymerisation bei Temperaturen von 100 bis 120°C im Hochvacuum wurden die Monomeren auf einen anorganischen Träger (Kieselgur, Celite®) sehr geringer Korngröße aufgebracht. Die Hauptfraktionen der erhaltenen Polymere hatten mittlere Molgewichte (Mw) von 20000-30000 [Poly(Ala-Lac) (10)] und 80000-90000 [Poly(Val-Lac) (17)]. Die erzielten Ausbeuten betrugen 50, bzw. 75%. Es wurde mit zwei unabhängigen Methoden (Totalhydrolyse und Hydrazinolyse der alternierenden Esterbindungen) nachgewiesen, daß die Polymere racemisierungsfrei sind. Die Abbauprodukte wurden mit Hilfe von CD-Spektroskopie, L-Lactatdehydrogenase und optischer Drehung auf ihre optische Reinheit untersucht.
    Notes: Polydepsipeptides with repeating units alanyl-lactyl and valyl-lactyl were synthesized by thermal polymerization of the pentachlorophenyl ester trifluoroacetate salts of L-alanyl L-lactyl L-ananyl L-lactic acid and L-valyl L-lactyl L-valyl L-lactic acid. The depside linkages of these monomers were formed using N,N′-carbonyldiimidazole and the peptide bond by coupling a N-Boc-protected depside acid in the presence of N,N′-dicyclohexylcarbodiimide to a C-benzyl protected despide amine. Alternatively a N-Boc-protected depside acid was coupled by the mixed anhydride method to the amino depside pentachlorophenyl ester. This was accomplished by taking advantage of the different reaction rates of the aminolysis of the mixed anhydride and the pentachlorophenyl ester. The thermal polymerization was carried out with the monomers deposite on a micro-sized inorganic matrix, Kieselguhr, at temperatures between 100 and 120°C under high vacuum. The main fraction of polymer obtained had an average molecular weight (M̄w) of 20000-30000 for poly(Ala-Lac) (10) and 80000-90000 for poly(Val-Lac) (17). Typical yields for these polymerizations were 50 and 75%, respectively. The polymers were found to be free from racemization by two independent methods: total hydrolysis and hydrazinolysis of the alternating ester bonds. The degradation products were investigated for their optical purity by measurements of circular dichroism. optical rotation. and L-lactate dchydrogenase digestion.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1975.020011975103
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Hydrolysis kinetics of terephthalic and 5-sulfonatoisophthalic acid esters14th communication in the series „Synthesefasern in der Wollindustrie“; for 13th communication see: V. Rossbach, H. Müller, D. Nissen, Textilveredlung 9, 339 (1974).Dedicated to Professor Dr. Eugen Müller on the occasion of his 70th birthday (1975)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 176 (1975), S. 2839-2852 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Kinetik der Verseifungsreaktion von Terephthalsäure-bis(2-hydroxyäthyl)ester (3) und Natrium-3,5-bis(2-hydroxyäthoxycarbonyl)benzolsulfonat (6) wird mit Hilfe der pH-stat-Technik im alkalischen pH-Bereich gemessen (pH 8 bis 10 bei 50 bis 80°C), um die Geschwindigkeitskonstanten der hydrolytischen Konsekutivreaktion für die Diester und die intermediär entstehenden Monoester zu bestimmen. Die experimentell ermittelten Gesamtreaktionsgeschwindigkeitskonstanten werden zerlegt in die einzelnen Geschwindigkeitskonstanten für die durch das Lösungsmittel, die OH--Ionen, die SO-3 ;-Gruppen, bzw. die COO--Gruppen katalysierten Teilreaktionen der Hydrolyse (k0, kOH-, kSO-3, kCOO-). Es wurde weder eine „Autokatalyse“ durch das Lösungsmittel noch eine intermolekulare Katalyse durch die Sulfonato- oder Carboxylatogruppen festgestellt. Die Aktivierungsparameter der Hydrolyse sind für die entsprechenden Ester beider Sauren gleich; für die Diester 3 und 6: 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-1 K-1 [-21,4 (- 23,3) cal mol-1 K-1]; für die Monoester (Terephthalsäure-mono(2-hydroxyathy1)-ester, bzw. 5-Natriumsulfonatoisophthalsäure-mono(2-hydroxyäthyl)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-1 K-1 [-20,6(-22,2) cal mol-1 K-1]. Für die geringere hydrolytische Stabilität von Polyesterfasern, die mit sulfonatogruppenhaltigen Comonomeren modifiziert sind, diirften aufgrund der Befunde überwiegend Fehlstellen in der Feinstruktur und nicht katalytische Effekte der Säuregruppen verantwortlich sein.
    Notes: The 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-3 groups 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 diesters 3 and 6: 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-1 K-1 [-21,4 (-23,3) cal mol-1 K-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-1 K-1 [-20,6 (-22,2) cal mol-1 K-1]. It is concluded that disorders in the fine structure of polyester fibers modified with sulfonato group containing comonomers may primarily be responsable for their lower hydrolytic stability and not any catalytic effects of these groups.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1975.021761006
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Chemische Analytik von SynthesefasernHerrn Professor Paul Schlack zum 75. Geburtstag gewidmetErweiterte Fassung eines Vortrags auf dem 4. Textil-Technischen Forum, Schloß Elmau 1972; 7. Mitteilung der Reihe: Synthesefasern in der Wollindustrie. 6. Mitteilung: W. L. Lindner, Polymer 14, 9 (1973). (1973)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 85 (1973), S. 691-706 
    Details
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die analytische Charakterisierung von Synthesefasern hat mit deren Entwicklung und Produktion nicht Schritt gehalten. Nachdem bereits Fasern der „zweiten Generation“ den Markt erobert haben, sind die bislang angewendeten chemischen Untersuchungsmethoden für die drei klassischen Faserpolymere vom Polyester-, Polyamid- und Polyacrylnitril-Typ noch häufig unbefriedigend. Sie genügen zwar den Erfordernissen der Produktionsüberwachung und Qualitätskontrolle, doch reicht ihre Aussagekraft nicht für das Verständnis und die Aufklärung von Abbau und Schädigung der Polymeren bei hydrolytischer, thermischer oder thermooxidativer Belastung. Dieser Bericht stellt chemische Analysenverfahren vor, die für derartige Untersuchungen an Synthesefasern neue Möglichkeiten eröffnen. Die für Handelsprodukte mitgeteilten Ergebnisse sind nicht als Qualitätsbeurteilung aufzufassen. Sie sollen vielmehr zeigen, welche Vielfalt in den chemischen Eigenschaften zu erwarten ist, und die Praxisbezogenheit der chemischen Analytik von Synthesefasern unterstreichen.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ange.19730851603
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Chemical Analysis of Synthetic FibersExpanded version of a lecture to the 4th Textile Technical Forum, Schloss Elmau, 1972; 7th report in the series: Synthetic Fibers in the Wool Industry. 6th report: W. L. Lindner, Polymer 14, 9 (1973).Dedicated to Professor Paul Schlack on the occasion of his 75th birthday (1973)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 12 (1973), S. 602-617 
    Details
    ISSN: 0570-0833
    Keywords: Analytical methods ; Fibers ; Polymers ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The analytical characterization of synthetic fibers has not kept pace with their development and production. Whereas the “second-generation” fibers have already conquered the market, the chemical investigation methods used until now for the three classical fiber polymers of the polyester, polyamide, and polyacrylonitrile types are still frequently unsatisfactory. Though they satisfy the requirements of production supervision and quality control, they do not supply enough information to enable us to understand and to explain the degradation of and damage to the polymers under hydrolytic, thermal, or thermooxidative influences. This report presents methods of chemical analysis that open up new possibilities for investigations of this nature on synthetic fibers. The results reported for commercial products must not be taken as an assessment of quality. They are simply intended to show the diversity to be expected in the chemical properties and to emphasize the practical basis of the chemical analysis of synthetic fibers.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.197306021
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    facet.materialart.
    Unknown
    B-Chain Shortening of Matrix-Bound Insulin with Pepsin, II. Preparation and Properties of Camel Des-Pentapeptide(B26-30)- and Des-PheB1-des-Pentapeptide(B26-30)-Insulin (1975)
    De Gruyter
    Details
    Publication Date: 1975-01-01
    Print ISSN: 0018-4888
    Topics: Biology , Chemistry and Pharmacology
    Published by De Gruyter
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...