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  • 1
    Electronic Resource
    Electronic Resource
    Studies on chemical resistance of polyesters (1988)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 156 (1988), S. 21-27 
    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: Es wurden Polyester basierend auf 1,4,5,6,7,7-Hexachlor-5-norbornen-2,3-dicarbonällureanhydrid (I), Tetrachlorphthalsäureanhydrid (II), Dibromneopentylglykol (II), ein Polyesterblend (V) bestehend aus dem Polyester (III) und einem Polyester (IV) für allgemeine Zwecke, ein Polyester (VI) basierend auf 1,4,5,6,7,7-Hexachlor-5-norbornen-2,3-dicarbonsäureanhydrid und dem Polyester III und ein Polyesterblend (VII) bestehend aus den Polyestern I und III hergestellt. Ihre chemische Resistenz und ihre Feuchtigkeitsaufnahme bei Temperaturen von 25 und 65°C wurden in Säuren, 20% NaOH und Wasser untersucht. Hierbei wurde gefunden, daß der Polyester (III) von den Säuren am wenigsten angegriffen wird. Verglichen mit unbehandelten Poly meren fand bei beiden Temperaturen in 20% NaOH eine Gewichtsabnahme bei allen Polyestern statt, mit Ausnahme des Polyesters VII. Erne Gewichtszunahme aller Polyester wurde beobachtet durch Feuchtigkeitsaufnahme sowohl bei 25 als auch bei 65°C, wobei die Zunahme bei der höheren Temperatur größer war. Der Polyester III zeigte die geringste Feuchtigkeitsaufnahme.
    Notes: Chlorendic anhydride based polyester (I,) tetrachlorophthalic anhydride based polyester (II), dibromoneopentyl glycol based polyester (III,) general purpose polyester (IV,) blend of dibromoneopentyl glycol based polyester with general purpose polyester (V,) chlorendic anhydride and dibromoneopentyl glycol based polyester (VI), and a blend of chlorendic anhydride based polyester and dibromoneopentyl glycol based polyester (VII) were prepared and their chemical resistance and moisture absorption studied in various reagents, acid, alkali, and water, at 25 and 65°C. It is found that the polyester (III) is the least affected in the presence of the acids. In 20% NaOH, there was a decrease in weight for all polyesters at both the temperatures compared to the control except the polyester (VII). Increase in weight of all the polyesters was observed during the absorption of moisture both at 25 and 65°C. The increase was higher at higher temperature. Polyester (III) thus shows the least absorption of moisture.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1988.051560102
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  • 2
    Electronic Resource
    Electronic Resource
    Complexes of Azaphospholes: Synthesis and Structure of Pentacarbonyl-(η1)-2-phosphaindolizine)chromium(0), -molybdenum(0), and -tungsten(0) (1998)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1998 (1998), S. 1079-1086 
    Details
    ISSN: 1434-1948
    Keywords: Phosphorus heterocycles ; P ligands ; Transition metals ; Carbonyl complexes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The complex chemical behaviour of 2-phosphaindolizines 1 (1,3-azaphospholo[1,5-a]pyridines) towards metal carbonyl compounds was studied. (η1-2-Phosphaindolizine)M(CO)5 complexes 2-4 (M = Cr, Mo, W) were formed from 1 and [(THF)M(CO)5], the cis-L2Cr(CO)4 complex 5f from 1f and tetracarbonyl(norbornadiene) chromium(0). The reaction of 2-phosphaindolizines 1e, 1f, or 1g with tricarbonyl(cycloheptatriene)molybdenum(0) or tricarbonyl(mesitylene)tungsten(0) yielded σ-complexes of the types L2M(CO)4or L3M(CO)3 rather than isolable π-complexes. In one case a strong upfield signal (δ31P = 6.1) was observed with a coordination shift of Δδ = -161.7, which is typical for π-coordination. Prolonged reaction or work-up led, however, to dismutation yielding 1g and the fac-L3Mo(CO)3 complex 6g. X-ray structure analysis of 2a indicates an increased 10π-delocalization compared with 1a and a changed conformation of the acyl substituent. The influence of substituents and metals on the 31P and 13C complexation chemical shifts and coupling constants is discussed.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Thermal stability and degradation studies of polyester resins (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 37 (1989), S. 1901-1908 
    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: Thermal behavior and degradation mechanisms of three polyester resins, namely bisphenol A based, isophthalic acid based, and general purpose were studied. These resins were cured with styrene in the presence of benzoyl peroxide (BPO) and methyl ethyl ketone peroxide (MEKP) as initiators. The cured resins were studied by thermogravimetric analysis and mass spectrometry. From the thermogravimetric data it was observed that the cured bisphenol-A-based polyester resin was thermally more stable than the cured isophthalic acid-based and general purpose polyester resins. It was also observed that polyester resins cured with MEKP are thermally more stable than benzoyl peroxide-cured products. Thermogravimetric analysis data shows that there are two first-order degradation reactions during thermal degradation in nitrogen atmosphere. The first degradation step involves the scission of cross-links/weak links with the liberation of free linear chains. The second step involves a random scission of the free linear chains into smaller fragments. The framentation patterns of the polyester resins were identified by mass spectrometery. Possible mechanisms for the degradation of the cured polyesters accounting for the experimental observations are discussed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1989.070370713
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  • 4
    Electronic Resource
    Electronic Resource
    Substitution of 2-phosphaindolizines by bromine and by chlorophosphines (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Heteroatom Chemistry 3 (1992), S. 359-366 
    Details
    ISSN: 1042-7163
    Keywords: Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bromine does not add to phosphorus in a 2-phosphaindolizine 1 but substitutes its 1-position. The 1-bromo derivatives 2 are best prepared with Br2/NEt3 or N-bromosuccinimide. Their hydrolysis is remarkable; it involves a debromination of C-1, an oxidation of P and a selective opening of the P/C-3 bond.PCl3 also causes a substitution of the 1-position. The resulting 1-dichlorophosphino derivatives 5 easily undergo a substituent exchange at the exocyclic phosphorus. More 1-phosphino derivatives are formed in the reaction of 1 with phenyl and diazaphospholyl dichlorophosphine.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hc.520030409
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  • 5
    Electronic Resource
    Electronic Resource
    1, 3-azaphospholo[5, 1-b]thiazolines and benzothiazolesIn part reported at the 8th International IUPAC Conference on Organic Synthesis, Helsinki 1990. (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Heteroatom Chemistry 3 (1992), S. 351-357 
    Details
    ISSN: 1042-7163
    Keywords: Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The title compounds 3 and 7 are novel heterocyclic systems incorporating two-coordinate phosphorus. They are obtained in reasonable to good yields from the condensation of suitable 2-ethyl-3-alkylthiazolinium and -benzothiazolium bromides 2 and 6 with phosphorus trichloride in the presence of triethylamine in an aprotic solvent. Intermediate dichlorophosphino-substituted N-ylides can be observed or isolated in some cases. From a 2-methyl-3-alkylthiazolinium bromide (2a), a 1-(dichlorophosphino) substituted 1, 3-azaphospholo[5,1-b]thiazoline (4) was obtained.The chemical shift of the two-coordinate phosphorus in 1,3-azaphosphole derivatives clearly reflects the influence of the heterocyclic system annulated to its 1,5-bond and of the substituents in its 2-and 4-positions.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hc.520030408
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  • 6
    Electronic Resource
    Electronic Resource
    2-phosphaindolizines (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Heteroatom Chemistry 9 (1998), S. 333-339 
    Details
    ISSN: 1042-7163
    Keywords: Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Eight new 2-phosphaindolizines 2 have been obtained by [4 + 1] cyclocondensation of 1,2-dialkylpyridinium halides 1 with PCl3. The X-ray structure analysis of 2a is consistent with the integration of the 1,3-azaphosphole ring in the 10π-aromatic system. The charge densities on phosphorus of various representatives as obtained by PM3 calculations correlate approximately with the 31P-NMR shifts. The mass spectral fragmentation of 2a resembles that of its nonphosphorus analog. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9:333-339, 1998
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Sulfur and selenium derivatives of 2-phosphaindolizinesDedicated to Prof. Heinrich Nöth on the occasion of his seventieth birthday. (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Heteroatom Chemistry 9 (1998), S. 445-452 
    Details
    ISSN: 1042-7163
    Keywords: Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 2-phosphaindolizines 1 react with hydrogen sulfide and elemental sulfur to give the new zwitterionic heterocyclic systems 2 of the N-pyridiniomethyl dithiophosphinate type. In contrast, no reaction is observed with sulfur alone. MeI methylates 2e,f at sulfur. The analogous pyridiniodiselenophosphinate 5 results from the reaction of 1a with 1,3,2,4-diselenadiphosphetane-2,4-diselenide, 4a, in the absence of an additional base. As a further product, the perselenophosphinic anhydride 6 is identified. In the presence of triethylamine, 1a reacts with each of the diselenides 4a-c to give the new triethylammonium diselenophosphinates 7a-c, respectively. This reaction can be extended to 1-aza-2-phosphaindolizine, 8, which yields with each of 4a,b and NEt3 the diselenophosphinates 9a,b, respectively. The anhydride 6 and the diselenophosphinates 7 and 9 result from an electrophilic substitution at the phosphaindolizine ring. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9:445-452, 1998
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    2-Phosphaindolizines (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 475-480 
    Details
    ISSN: 0009-2940
    Keywords: 1,3-Azaphosphole, annulation to pyridine ; 2-Phosphaindolizines ; Pyridinium bromides, 1,2-dialkyl ; Phosphorus(III) chloride, condensation with CH2 groups ; Calculations, MNDO ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240309
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  • 9
    Electronic Resource
    Electronic Resource
    O/NMe2 exchange in the reaction of 4-benzylidene-5-oxazolones with phosphorous tris(dimethylamide) (1988)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 121 (1988), S. 2067-2069 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 4-Benzylidene-5-oxazolones 5 do not react with P(OMe)3; with P(NMe2)3 they give rise to 4-α-[bis(dimethylamino)phosphoryl]benzyl-5-dimethylaminooxazoles 6. This behavior differs from that of the corresponding pyrazolones and isoxazolones and is attributed to a decreased stability of the dipolar adduct resulting from a β attack of phosphorus.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19881211128
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  • 10
    Electronic Resource
    Electronic Resource
    1,4,2-Diazaphospholothiazoles and -pyridines by a Hantzsch-Type Condensation Using Chloromethyldichlorophosphane (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 581-587 
    Details
    ISSN: 0009-2940
    Keywords: Anellated azaphospholes ; Hantzsch-type [3 + 2] cyclocondensation ; Chloromethyldichlorophosphane ; Regioselectivity ; 31P-, 1H-, 13C-NMR spectra ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The [3 + 2] cyclocondensation of 2-amino-1,3-thiazoline, 2-aminopyridines, 2- and 4-aminopyrimidines, 2-aminopyrazine, and 2-aminoquinoline with chloromethyldichlorophosphane in the presence of triethylamine yields regiospecifically 5,6-dihydrothiazolo[2,3-e][1,4,2]diazaphosphole (3), 1,4,2-diazaphospholo[4,5-α]pyridines (12), 1,4,2-diazaphospholo[4,5-α]pyrimidines (15), 1,4,2-diazaphospholo[4,5-e]pyrimidine (17), 1,4,2-diazaphospholo[4,5-α]pyrazine (19), and [1,4,2]diazaphospholo[4,5-α]quinoline (22), respectively. Using 2-amino-1,3-thiazole (4) and 2-aminobenzothiazoles 8, we obtained mixtures of the 1,5- and 4,5-anellated 1,4,2-diazaphospholes 5/6, 9a/10a and 9b/10b, while in the case of the methyl derivative 8c only the [1,4,2]diazaphospholo[5,4-b][1,3]benzothiazole 10c was formed. In the reaction of 2-aminothiazole and 2-aminopyrazine with Chloromethyldichlorophosphane the bis(diazaphospholo)-substituted chloromethylphosphanes 7 and 20 could be detected. The new anellated 1,4,2-diazaphospholes are colorless to pale yellow crystalline moisture-sensitive solids.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19951280610
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