ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • Chemical Engineering  (77)
  • Organic Chemistry
  • GENERAL
  • 1990-1994  (114)
  • 1960-1964
  • 1955-1959
  • 1925-1929
  • 1993  (114)
Sammlung
Verlag/Herausgeber
Erscheinungszeitraum
  • 1990-1994  (114)
  • 1960-1964
  • 1955-1959
  • 1925-1929
Jahr
  • 1
    ISSN: 0894-3230
    Schlagwort(e): Organic Chemistry ; Physical Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: The methyl ester of 1H-indazole-3-carboxylic acid (2-Me) is formed in the diazotization of o-aminophenylacetic acid to o-diazoniumphenylacetic acid (1) in an intramolecular aliphatic diazonium coupling. 2-Me was identified and characterized by single-crystal x-ray diffraction and found to crystallize as hydrogen-bonded trimers of crystallographically independent molecules. The methylcarboxy groups are rotated slightly out of the best plane of the trimer resulting in only a pseudo-threefold axis. The crystal structure of 2-Me is compared with other indazoles and pyrazole. Regioselective electrophilic diazonium ion addition to the enol tautomer of 1 and subsequent hyrazone-azo tautomerization are proposed as a possible mechanism for indazole formation under acidic conditions. The tautomerization equilibrium between acetic acid and its enol 1,2-dihydroxyethene was studied and the effects of phenyl and o-diazoniumphenyl substitution on this equilibrium were explored with semi-empirical quantum mechanical methods. The performance of the semi-empirical method was assessed by comparison with ab initio and/or experimental data. It was found that the enol of o-diazoniumphenylacetic acid is stabilized greatly owing to extended conjugation and push-pull interactions in the enol form. These results suggest that the enol tautomer might be a viable reactive intermediate that warrants considerations in discussions of reaction mechanisms.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 2
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 316-318 
    ISSN: 0894-3230
    Schlagwort(e): Organic Chemistry ; Physical Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: It is shown that a theoretical computation of the Dewar resonance energy of decamethyl [5] pericyclyne should give the same value for the homoaromaticity of this compound as that calculated earlier from heat of hydrogenation measurements. Both methods show this quantity to be small, but the accuracy of the methods appears insufficient for more exact agreement.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 3
    Digitale Medien
    Digitale Medien
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 33 (1993), S. 75-82 
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Water sorption in epoxy based materials was analyzed by dielectric spectroscopy using remote sensors. A method to determine diffusion coefficients from the changes in permittivity during water absorption is proposed and was verified experimentally by comparison with standard water gain measurements. Although the technique is limited by electrode polarization phenomena, it is sensitive to the presence of water molecules and is capable of detecting different levels of water concentration as a function of frequency. The utilization of remote sensors demonstrated the capability of dielectric analysis to be applied both in the laboratory environment, and on a larger scale, as a nondestructive technique for monitoring environmental changes in actual polymer matrix composite parts.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 4
    Digitale Medien
    Digitale Medien
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 33 (1993), S. 913-922 
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Semi-interpenetrating networks have been produced from castor oil and poly(ethylene terephthalate) (PET). Bond interchange between PET and castor oil plays a major role in the development of initial miscibility, also affecting morphology and chemical structure. Microheterogeneous morphology is developed for materials of intermediate composition, which have much greater toughness than the polymers from which they were made.
    Zusätzliches Material: 14 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 5
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 39 (1993), S. 235-248 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The addition of cosolvents to supercritical fluid (SCF) solvents can have large effects on solubilities, giving engineers the ability to tailor loadings and selectivities of solutes for difficult separations. It is necessary to have a better understanding of the special intermolecular interactions that occur in SCF solutions to predict the effects of cosolvents. We use a SCF chromatographic technique to acquire a database of cosolvent effects for a variety of cosolvents and solutes; examination of the cosolvent effects shows evidence of hydrogen bonding, charge transfer complex formation, and dipole-dipole coupling between solute and cosolvent molecules. SCF solvents, carbon dioxide, ethane, and fluoroform, are compared, and then the use of the chromatograph to measure solubilities is discussed.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 6
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 39 (1993), S. 745-756 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The flow field inside an orifice flowmeter with a beta ratio of 0.50 operating at a Reynolds number of 91,100 has been studied using a three-color, 3-D laser Doppler anemometer system. Mean velocity measurements show large radial velocities leading into the orifice, the fluid separating from the orifice plate at the throat, the presence of a vena contracta farther downstream, flow reattachment to the pipe wall 5.3 pipe radii (R) downstream, the presence of a small upstream recirculation zone, and both a primary and secondary recirculation zone downstream of the orifice plate. The static wall pressure distribution attains a minimum pressure at 1.5 R, which does not coincide with the location of the vena contracta (0.75 R). Distributions of the entire Reynolds stress tensor are presented along with calculated values of turbulence kinetic energy, turbulence kinetic energy production, vorticity, and turbulence induced accelerations. These data are analyzed to interpret the complex turbulent flow field.
    Zusätzliches Material: 16 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 7
    Digitale Medien
    Digitale Medien
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 33 (1993), S. 1489-1493 
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Reported is an attempt to attain orientation of macromolecules during extrusion of films of cellulose derivatives that led to the liquid-crystalline state of a polymer and resulted in enhanced film strength.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 8
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Extracts from the seeds of Annona muricata yielded three new Annonaceous acetogenins: muricatetrocin A (= (5S)-3-{(2R)-2-hydroxy-9-{(2R,5S)-tetrahydro-5-[(1S,4S,5S)-1,4,5-trihydroxyheptadecyl]furan-2-yl}nonyl}-5-methylfuran-2(5H)-one; 1), muricatetrocin B (= (5S)-{(2R)-2-hydroxy-9-{(2S,5S)-tetrahydro-5-[(1S,4S,5S)-1,4,5-trihydroxyheptadecyl]furan-2-yl}nonyl}-5-methylfuran-2(5H)-one; 2), and gigantetrocin B (= (5S)-3-{(2R)-2-hydroxy-7-{(2S,5S)-tetrahydro-5-[(1S,4R,5R)-1,4,5-trihydroxynonadecyl]furan-2-yl}heptyl}-5-methyl-furan-2(5H)-one; 3). Their C-skeletons were deduced by mass spectrometry. Configurations were determined by 1H-NMR of ketal derivatives and 2D-NMR experiments utilizing Mosher esters. A previously described compound, gigantetrocin A (= (5S)-3-{(2R)-2-hydroxy-7-{(2S,5S)-tetrahydro-5-[(1S,4S,5S)-1,4,5-trihydroxynonadecyl]furan-2-yl}heptyl}-5-methylfuran-2-(5H)one; 4), was also isolated and is new to this species. Compounds 1-4 were all selectively cytotoxic for the HT-29 human colon-tumor cell line with potencies at least 10 times that of adriamycin.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 9
    Digitale Medien
    Digitale Medien
    Brookfield, Conn. : Wiley-Blackwell
    Polymer Composites 14 (1993), S. 144-150 
    ISSN: 0272-8397
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Maschinenbau
    Notizen: When a resin in injected into the mold in liquid composite molding, the preplaced fiber mat may deform near the inlet gate because of the high momentum carried by the injected fluid. A fiber free region near the gate followed by the fiber mat deformation may emerge. This phenomenon is most likely to occur when the stacked fiber mats have low permeability and the resin has high viscosity. A set of mold filling experiments were carried out using an instrumented metal mold and a small transparent mold to investigate the fiber mat deformation during mold filling. Experimental results showed that the fiber mat deformation was limited to a small region near the gate and that deformation greatly reduced the molding pressure. A forced fiber mat deformation employing a modified gate design was proposed to facilitate mold filling in liquid composite molding.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 10
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 7 (1993), S. 577-581 
    ISSN: 0268-2605
    Schlagwort(e): Organoarsenic ; sodium tetraethylborate ; gas chromatography-atomic absorption spectrometry ; cold trap-atomic absorption spectrometry ; Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The compounds MeAsBr2 and Me2AsBr at concentrations of (1-5) × 10-3 M in acetone solution are ethylated in high yield by NaBEt4 to MeEt2As and Me2EtAs, as shown by 1H NMR spectroscopy. The extents of ethylation of MeAs2+ and Me2As+ (expressed as ions, by convention) in aqueous acid solutions [at concentrations of (5-20) × 10-6 M] were investigated using cold trap/AA and GC AA procedures. The species Me2As+ was ethylated (to give Me2EtAs) in good yield (88%); in contrast, MeAs2+ produced the volatile trialkylarsine, MeEt2As, in poor yield (30%). No volatile trialkylarsine could be obtained on treating inorganic arsenic(III) (As3+) solutions with NaBEt4.
    Zusätzliches Material: 5 Tab.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...