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  • Wiley-Blackwell  (1,046)
  • American Association of Petroleum Geologists  (163)
  • 1985-1989  (768)
  • 1970-1974  (332)
  • 1950-1954  (109)
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  • 1
    Electronic Resource
    Electronic Resource
    Synthesis of 2,3,4,6,7,8-Hexahydro-5H-1-benzopyran-5-ones and 3-(6-Oxo-1-cyclohexenyl)alkanoic Acids by Reduction of 4,6,7,8-Tetrahydro-2H-1-benzopyran-2,5(3H)-diones (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 1681-1684 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Comparative results on the reduction of 4,6,7,8-tetrahydro-7,7-dimethyl-2H-1-benzopyran-2,5(3H)-diones 1 are reported. Hydride reduction (LiAlH4 in Et2O or NaBH4 in i-PrOH) affords 2,3,4,6,7,8-hexahydro-5H-1-benzopyran-5-ones 5 in 30-60% isolated yield. Photochemical reduction of 1b and 1d (direct irradiation at λ = 300 or 254 nm in i-PrOH, or sensitized irradiation in acetone/i-PrOH or benzene/i-PrOH) gives 3-(6-oxo-1-cyclohexenyl)alkanoic acids 6 in 50-80%, while 1c affords the isomeric 3-(4,4-dimethyl-6-oxo-1-cyclohexenyl)-4-methyl-4-pentenoic acid (9) in 73% isolated yield. Electrochemical reduction (Hg, CH3CN, Bu4N+ClO4-, -2.6 V vs. Ag/Ag+) requires more than 4 Farad/mol for the consumption of 1 without any major product being detected.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19860690723
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  • 2
    Electronic Resource
    Electronic Resource
    Analysis of the polycyclic aromatic compounds of diesel fuel by gas chromatography with ion-trap detection (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 517-519 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Capillary column gas chromatography combined with ion-trap detector mass spectrometry was used in the identification of 85 constituents of the polycyclic aromatic hydrocarbon fraction of diesel fuel. The main constituents are an extensive range of alkylnaphthalenes; alkylated tetrahydronaphthalenes, benzothiophens, dibenzothiophens biphenyls, fluorenes and phenanthrenes were also identified. Chromatographic retention indices for these compounds were determined to calibrate retention data for routine analysis with flame-ionization detection, and to identify positions of alkyl substitution.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200150909
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  • 3
    Electronic Resource
    Electronic Resource
    An experimental study of the control of condensate subcooling in a vertical condenser (1973)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 19 (1973), S. 923-928 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Temperature control of subcooled reflux in a distillation column was studied experimentally using coolant flow rate as the manipulative variable. Methanol vapor was condensed and subcooled at one atmosphere in a vertical heat exchanger with 210 copper tubes (0.77 cm I.D., 91.5 cm long). Cooling water flowed countercurrently through the shell side (20.6 cm I.D.).A proportional-integral feedback controller provided good temperature control at normal design throughputs. But dynamic control performance deteriorated at low throughputs (or large areas). Thus the normal conservative design practice of providing excess area in this type of condenser leads to poorer temperature control.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690190506
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  • 4
    Electronic Resource
    Electronic Resource
    Proton magnetic resonance studies of the conformational changes of dideoxynucleoside ethyl phosphotriestersPart II of a series entitled Alkyl Phosphotriesters of Dinucleotides and Oligonucleotides. (1973)
    New York : Wiley-Blackwell
    Biopolymers 12 (1973), S. 2225-2240 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: PMR investigations on the diastereomeric phosphate methyl protons of the dinucleoside ethyl phosphotriesters Tp(C2H5)T, dA, and dIp(C2H5)dI have been used to study the conformational changes of these dimersin solution. In D2O (273°K), the diastereomeric phosphate-methly groups of Tp(C2H5)T appear as a triplet. The methyl resonances of dIp(C2H5)dI and dAp(C2H5)dA appear as two sets of triplets and their chemical shift differences (δ1 - δ2), decrease with increasing temperature, finally becoming zero at 292°K and 333°K, respectively. The same phenomenon is observed for dAp(C2H5)dA in CD3OD; in this detacking solvent, the difference (δ1 - δ2) diminishes to zero at a lower temperature (261°K). At room temperature in D2O, the chemical shift of the phosphate methyl of Tp(C2H5)T appears at lower field than those of dIp(C2H5)dI or dAp(C2H5)dA. The differences between the chemical shifts of these groups (δI - δT or δA - δT) increase with increasing temperature, and reach maximal values at 301°K and 333°K, respectively. The results suggest that at low temperature the largest fraction of the dimer population exists in a stacked state, with the phosphate-ethyl groups outside the stack. Increasing temperature causes an oscillation of the bases and a shift in the dimer population away from the stacked state. Finally at high temperature, the planar bases rorate with respect to one another and in the case of dIp(C2H5)dI and dAp(C2H5)dA, the ethyl groups experience shielding by the anisotropic ring current of the five-membered ring of the bases. Thus, the current pmr studies and those reported earlier from our laboratory support an “oscillation-rotation model” for the unstacking process of the dimers. The relationship of this model and the “two-state model” is discussed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1973.360121004
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  • 5
    Electronic Resource
    Electronic Resource
    Factors affecting the production of glutamine in cultured mouse cells (1971)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 77 (1971), S. 135-144 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Glutamine synthetase activity of NCTC clone 929 mouse cells (strain L) was studied as a function of the prior nutritional experience of the cells. Small enzyme increases were recorded in response to either glutamine depletion or chronic serum supplementation of the growth medium. Somewhat greater increases resulted from the administration of cortisol or certain other steroids, particularly if the hormone treatment was combined with glutamine withdrawal. High concentrations of glutamate in the medium did not augment the glutamine synthetase content of the cells and even caused an apparent decrease in it. The presence of glutamine in the culture medium resulted in a fairly rapid rate of disappearance of the glutamine synthetase of previously induced cells. The data suggest that glutamine and cortisol act independently on the cells in regulating the level of the enzyme.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1040770203
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  • 6
    Electronic Resource
    Electronic Resource
    Shape group studies of molecular similarity and regioselectivity in chemical reactions (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 9 (1988), S. 608-619 
    Details
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: The study of the qualitative and quantitative product distribution in a chemical reaction, in particular regioselectivity, is of fundamental importance. Recently, it has been shown that the regioselectivity of some Diels-Alder cycloadditions can be explained by analyzing the interrelations between electron density contours and molecular electrostatic potentials. This problem is related to a central topic of modern theoretical chemistry and biochemistry: the analysis of molecular shape. This work deals with a rigorous, algebraic method to analyze these surfaces. The procedure is based on the computation of the shape groups (symmetry-independent homology groups of algebraic topology) of the molecular surface, using either a fully analytical algorithm requiring no visual inspection, or a precise method for processing pictorial information if the latter is available. The method provides a concise description of the molecular contour surface, that can replace the usually intuitive, and somewhat subjective, visual characterization of density and electrostatic potential contours. The method is illustrated for the case of Diels-Alder reactions by considering a number of monosubstituted dienes. Extensions of the analysis to dienophiles, as well as other types of reactions are also discussed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcc.540090606
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  • 7
    Electronic Resource
    Electronic Resource
    Séparation chromatographique par des gels de polystyrène preparés par réticulation anioniqueHerrn Professor Dr. W. KERN zu seinem 65. Geburtstag mit unseren allerbesten Wünschen gewidmet (1971)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 145 (1971), S. 105-121 
    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: Chromatographische Kolonnen wurden mit anionisch hergestellten Polystyrolgelen verschiedener Porengrößen gefüllt. Lineare Polystyrolproben wurden in diese Kolonnen eingespritzt, und die entsprechenden Elutionsvolumina wurden gemessen. Durch die normalisierten Elutionskurven - die die dynamischen Verteilungskoeffizienten in Abhängigkeit des Logarithmus des Molekulargewichtes des eingespritzten Polystyrols darstellen - wurde veranschaulicht, daß der Molekulargewichtsbereich, in dem chromatographische Trennung stattfinden kann, von den strukturellen Parametern des Gels abhängig ist, und zwar von dem Molekulargewicht des linearen Präpolymeren, von der Konzentration des Polymeren beim Vernetzungsvorgang und vom Anteil des Vernetzungsagens.Es wurde auch festgestellt, daß die chromatographischen Elutionsvolumina von Faktoren abhängig sind, wie der Größe der Gelpartikel und der Fließgeschwindigkeit des Eluenten. Dies zeigt, daß die Bedingungen zur Einstellung des Austauschgleichgewichtes zwischen den Gelporen und der fließenden Zwischenraumflüssigkeit nicht erfüllt sein können. Aber unter Verwendung von Standardbedingungen kann man reproduzierbare Ergebnisse erzielen, die zu gültigen Vergleichen dienen können.Es ist noch hervorzuheben, daß die Makroporosität eines Gels keineswegs als eine notwendige Bedingung für die chromatographische Trennung aufzufassen ist.
    Notes: Chromatographic columns were filled with anionically prepared polystyrene gels of various porosities. Linear polystyrene samples were injected in these columns and the retention volumes were measured. Normalized curves have been compared, the dynamic partition coefficient being plotted versus the logarithm of the molecular weight of the injected polymer. It has been established that the domain of molecular weights in which chromatographic separation may take place depends upon the parameters characterizing the gel: molecular weight of the linear “precursor”, overall concentration at the gel point, proportion of crosslinking agent.It has been found that the chromatographic retention times depend on such factors as size of gel particles, flow-rate of the elution solvent. This shows that the exchange equilibrium between the pores of the gels and the flowing intersticial liquid are far from being fulfilled. However by choosing standard conditions one gets reproducible results which may be adequately compared.It should be emphasized that macroporosity of a gel is not a prerequisit for chromatographic separation.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1971.021450109
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  • 8
    Electronic Resource
    Electronic Resource
    Préparation de gels réticulés par copolymérisation séquencée anionique du styrène avec le divinylbenzène (1970)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 135 (1970), S. 249-261 
    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: Durch anionische Blockcopolymerisation von Styrol und Divinylbenzol unter Einwirkung eines bifunktionellen Initiators wurden vernetzte Gele hergestellt. Die Reaktion wurde in aprotischen Lösungsmitteln und unter Argon-Atmosphäre durchgeführt. Die Gele wurden durch ihren maximalen Quellungsgrad charakterisiert. Es wurde festgestellt, daß die folgenden drei Parameter die Eigenschaften der Gele beeinflussen: das Molekulargewicht des linearen Polystyrols, aus dem das Gel hergestellt wird, die Konzentration desselben Polystyrols bei der Zugabe von DVB und die Menge des eingesetzten Divinylbenzols pro lebendes Kettenende. Man kann also auf diese Weise homogene Gele verschiedener Porosität synthetisieren. Im Unterschied zu radikalisch hergestellten Gelen ist bei den auf anionischem Wege erhaltenen Proben die Verteilung der Maschengrößen sehr eng, und der Gelpunkt hat hier eine physikalische Bedeutung. Außerdem ist es leicht, hier die Synärese auszuschalten.
    Notes: La préparation de gels réticulés peut être effectuée par copolymérisation séquencée anionique de styrène et de divinylbenzène, sous l'action d'un promoteur bifonctionnel, en milieu aprotique et en atmosphère inerte. Les gels sont caractérisés par leur taux de gonflement maximum. La masse moléculaire moyenne du polystyrène «parent», la concentration globale de la solution, au moment de la réticulation, et la proportion de DVB mise en jeu constituent les trois paramètres qui déterminent la porosité et la structure même du gel. On peut donc préparer à volonté des réticulats homogènes de porosités très différentes.Dans un tel gel la distribution des tailles des mailles est fort étroite; la synérèse peut être aisément évitée; la signification physique du «point de gel» est bien établie. Ces trois propriétés de la réticulation anionique ne se retrouvent pas dans les gels préparés par voie radicalaire et justifient l'étude de ces gels.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1970.021350123
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  • 9
    Electronic Resource
    Electronic Resource
    Etude du gonflement de gels réticulés préparés par copolymérisation séquencée anionique (1971)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 141 (1971), S. 145-159 
    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: The swelling behavior of a series of crosslinked polystyrene gels prepared anionically has been investigated. The degree of swelling of these gels at equilibrium, in a solvent, was found to depend on their structural characteristics which are determined by the conditions of preparation of the gels.The variation of the degree of swelling versus the structural parameters were found in good agreement with the theoretical expectations, for “ideal” networks. Some gels, however, exhibit a non-ideal behavior which can be explained by a decrease of the number ve of elastic chains, owing to free chain ends and to coupling.
    Notes: Das Quellungsverhalten von vernetzten Gelen, die auf anionischem Wege hergestellt wurden, wurde untersucht. Der Quellungsgrad der Gele im Gleichgewicht ist stark strukturabhängig und durch die Bedingungen ihrer Herstellung beeinflußt. Die experimentell erhaltenen Werte des Quellungsgrades stehen in guter Übereinstimmung mit den für ideale Gele aus den strukturellen Parametern berechneten Werten. In einigen Fällen allerdings wurden Abweichungen beobachtet, die durch die Gegenwart von freien Kettenenden oder von Kupplungen (Knoten mit Funktionalitätswert 2) oder von beiden zugleich verursacht werden. In diesen Fällen kann kein Idealmodell die Eigenschaften der Gele erklären.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1971.021410111
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  • 10
    Electronic Resource
    Electronic Resource
    Spectroscopic studies of polymerized surfactants: 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphocholine (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 2203-2216 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Spectroscopic studies have been performed on aqueous dispersions of the surfactant 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphocholine before and after polymerization with ul-traviolet light. Monomers of this lipid can, under certain conditions, convert from the expected spherical liposomal form to a unique phase consisting of hollow tubules. To determine the molecular conformation of these structures we have used Raman and infrared spectroscopies to probe the structure of the hydrocarbon chains and head groups of the lipids, and used absorption spectroscopy and resonance enhanced Raman scattering of the colored polymer to monitor the length and structure of the diacetylenic polymer backbone. Unusual C—H stretch-ing Raman bands imply that the hydrocarbon chain packing in the monomeric bilayers is different from that observed in other phosphatidylcholines, and that a distrubance in alkyl chain packing occurs on polymerization. Depending on irradiation conditions and the dispersal state of the lipid the polymer chains may be of at least three different colors, from which distinct resonance Raman spectra are obtained. The effective bond conjugation lengths range from quite short in the yellow polymer produced in sonicated vesicles to extremely long in a blue component seen in polymerized tubules.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180231015
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