Library

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
Filter
  • 1970-1974  (6)
  • 1960-1964  (12)
  • 1860-1869
  • 1810-1819
  • 1800-1809
  • Alkenes
  • Dyes/Pigments
  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 13 (1974), S. 305-312 
    ISSN: 0570-0833
    Keywords: Dyes/Pigments ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Despite sporadic investigations over many years the structures of the pigments responsible for most of the yellow, orange, and brown colors of mammalian hair, and of feathers, have remained unknown. However, recent work has shown that the major reddish-brown pigments, gallophaeomelanins, are polymers containing benzothiazole and tetrahydroisoquinoline units. The yellow-orange and violet trichochromes are minor pigments based on a new chromophore, Δ2,2′-bi(1,4-benzothiazine). Both groups arise in vivo from tyrosine and cysteine by a deviation from the biogenetic pathway which normally leads to the formation of eumelanins, the black pigments.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 11 (1972), S. 200-214 
    ISSN: 0570-0833
    Keywords: Elimination ; Stereochemistry ; Alkenes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Earlier evidence led to the view that in bimolecular olefin-forming eliminations the anti steric course is generally preferred over the syn. Recent experiments, however, show that in some common bimolecular elimination reactions, notably those involving onium bases, syn- and anti-eliminations proceed side by side, the former preferentially leading to the trans- and the latter to the cis-olefins.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 11 (1972), S. 596-606 
    ISSN: 0570-0833
    Keywords: Bond theory ; Alkenes ; Alkynes ; Alkene ligands ; Alkyne ligands ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The molecular orbital (MO) and valence bond (VB) descriptions of the bonding in metalolefin and -acetylene complexes are examined in relation to their ability to explain the known properties of these complexes. It is concluded that whereas there are difficulties with the valence bond description, the molecular orbital description can satisfactorily explain all the known properties of these complexes and has the necessary versatility to enable it to be readily applied to any series of metal-olefin or -acetylene complexes. It is further shown that olefin and acetylene complexes can be usefully divided into two main classes: those that resemble the platinum(II)-complexes (class S), and are either square-planar or octahedral with essentially free rotation about the metal-olefin bond; and those that resemble platinum(0)-complexes (class T) and are either trigonal planar or trigonal bipyramidal and in which there is no rotation about the metal-olefin or -acetylene bond.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 11 (1972), S. 964-973 
    ISSN: 0570-0833
    Keywords: Proton-active compounds ; Electron-rich alkenes ; Alkenes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Proton-active substances react with certain electron-rich olefins with cleavage of the central C=C double bond to give compounds that can be formally regarded as insertion products of nucleophilic carbenes. If they satisfy certain structural conditions, they isomerize with β elimination to give open-chain compounds. Both CH-acidic compounds and compounds containing NH or OH groups can undergo this reaction. The mechanisms are discussed, and the importance of the intermediate products to biochemistry (thiamine, tetrahydrofolic acid) is indicated.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 11 (1972), S. 1051-1061 
    ISSN: 0570-0833
    Keywords: Semiconductors ; Dyes/Pigments ; Materials science ; Industrial chemistry ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Effects of industrial interest have been detected in investigations on the dark conductivity and photoconductivity of dyes. For example, it was found that organic dyes can be used in the same way as inorganic photoconductors in vidicon television pickup tubes for the reproduction of images. Among other things, pointers were obtained to the formation of rectifying and photoelectrically sensitive pn junctions, to relatively high thermoelectromotive forces of doped and polymeric dyes, to the possibility of use in reprography, and to a high catalytic activity connected with the conductivity, which is already being utilized in fuel cells.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 9 (1970), S. 9-25 
    ISSN: 0570-0833
    Keywords: Dyes/Pigments ; Laser dyes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Laser technology has been developed to a very high level since 1960. Significant advances have been made possible only by the use of organic dyes as optical shutters for the production of giant pulses. Ultrashort pulses in the picosecond range were first produced in 1966; their measurement was greatly facilitated by the use of organic dyes. Probably the most important recent advance in the laser field is the dye laser, which was first described in 1966, and in which the active medium is a solution of an organic dye.
    Additional Material: 28 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 3 (1964), S. 245-249 
    ISSN: 0570-0833
    Keywords: Addition ; Alkenes ; Electrophilic reactions ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Various structures have been proposed for the intermediates of electrophilic additions onto olefins; these include halonium ions, classical carbonium ions, π-complexes (i.e. nonclassical carbonium ions), and π-complexes with back-coordination. It is shown here that it is impossible to use any one of these entities alone to explain all such electrophilic additions; the electrophile itself determines the nature of the transition state formed. Polar addition of hydrogen halides onto olefins appears to proceed via a classical carbonium ion which does not occur as the free ion but as an undissociated ion pair. Various other mechanisms have been excluded by studies reported here of the stereochemical course of such additions.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 3 (1964), S. 408-416 
    ISSN: 0570-0833
    Keywords: Reactive dyes ; Dyes/Pigments ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two new groups of reactive dyestuffs have been developed. One group (Levafix® dyes) comprises compounds which contain —SO2NH—CH2—CH2—OSO3H or —CH2—N(alkyl)-CH2—CH2—OSO3H as reactive groups. The dyes of this group react with cellulose fibers to form cellulose ethers, e.g. R—SO2NH—CH2—CH2—O—cellulose. The substances in the second group (Levafix-E® dyes) consist of the amides formed from 2,3-dichloroquinoxaline-6-carboxylic acid and dyestuffs containing primary or secondary amino groups.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 0570-0833
    Keywords: Koch carboxylic acid synthesis ; Carboxylic acids ; Alkenes ; Isomerization ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: When straight-chain mono-olefins, from pentene to decene, are subjected to the Koch carboxylic acid synthesis by the addition of CO and H2O or CH3OH in the presence of strongly acidic catalysts, not only the expected secondary acids, but also mixtures of a specific type of tertiary acids or their methyl esters are formed. When the catalysts contain boron trifluoride, the secondary acids are formed in ratios of isomers which are, within the scope of this investigation, independent of the experimental conditions and which agree well with the values calculated from the isomer equilibria of the corresponding n-olefins. Using concentrated sulfuric acid as catalyst, a larger proportion of tertiary acids is obtained than with BF3-catalysis, and amongst the secondary acids, those isomers predominate in which the COOH group is situated near the centre of the molecule.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 2 (1963), S. 20-23 
    ISSN: 0570-0833
    Keywords: Reactive dyes ; Dyes/Pigments ; Reactive dyes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Compounds and dyes containing vinylsulfonyl groups or groupings which readily yield vinylsulfonyl groups possess a marked ability to add onto many compounds containing active hydrogen under alkaline conditions. They also react with natural substances of high molecular weight, e.g. wool and cellulose, which contain amino- or hydroxyl groups. These reactions lead to the formation of strong covalent bonds between the reactants. As a result of this finding, reactive dyes for nitrogenous and cellulose fibers have been developed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 11
    ISSN: 0570-0833
    Keywords: Polycondensation ; Dyes/Pigments ; Bunte salts ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dyes which contain only thiosulfate residues as water-solubilizing groups are readily polycondensed on cellulose under mild conditions in the presence of condensing agents such as sodium sulfide to give insoluble, high molecular-weight dyes. This type of fixation leads to wash-fast dyeings and, in contrast to reactive dyes, involves no reaction with the fiber. The preparation and application of the dyes are described.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 12
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 2 (1963), S. 295-308 
    ISSN: 0570-0833
    Keywords: Emulsion polymerization ; Polymerization ; Polymerization ; Alkenes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ionizing radiation induces the polymerization of some vinyl monomers in aqueous emulsion with high radiation yields. With identical emulsion compositions, the kinetics of this reaction and the kinetics of emulsion polymerization induced by water-soluble initiators are very similar. The rate of reaction in emulsion polymerization is about one hundred times greater than in bulk polymerization. The initiation of emulsion polymerization by means of ionizing radiation permits uniform “illumination” of the reacting volume, as well as almost any desired variation in the frequency of initiation during the reaction. The sharp decrease in the overall rate of reaction when initiation is interrupted during emulsion polymerization of styrene induced by γ-rays contradicts the earlier concept of sharply separated reaction zones.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 13
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 2 (1963), S. 704-714 
    ISSN: 0570-0833
    Keywords: Titanium ; Alkenes ; Polymerization ; Titanium ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: At low temperatures, ethylene and α-olefins (Δ1-olefins or 1-alkenes) are rapidly converted into oligomrs by the two-component organometallic catalyst CH3TiCl3·CH3AlCl2. To achieve smooth oligomerizations, aromatic or chlorinated hydrocarbons must be used as solvents. Although the activity of the titanium-carbon bond is enhanced by the aluminum component of the catalyst, the aluminum and its methyl group do not participate in the reaction proper; the latter proceeds exclusively at the titanium-carbon bond. The reaction will olefins can be used as an analytical method for the quantitative determination of the titanium-carbon bond in admixture with the organoaluminum component. It is thus possible to follow the reaction leading to formation of the catalyst from titanium tertrachloride, as well as the processes occurring at the titanium-carbon bond during the oligomerization of olefins. All the observations indicate that the catalyst possesses an ionic structure which is determined by the solvent. It is shown that the initial reaction step probably involves formation of a complex between the olefin and the alkyltitanium cation. The reaction scheme proposed is based on organometallic reactions which are characterized by carbanion and hydride transfers within the olefin-cation complex. This mechanism, which is unusual for Ziegler catalysts, is due to the predominance of hydride transfers.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 14
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 1 (1962), S. 41-45 
    ISSN: 0570-0833
    Keywords: Dyes/Pigments ; Rutile structure ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Until the present time, new color pigments have been developed by isotypic and homotypic mixed-phase formation. This paper deals primarily with heterotypic mixed-phase formation for the preparation of new colored and white pigments with the rutile structure. Dioxides and difluorides crystallizing in the rutile lattice-form were chosen as host-lattices for the mixed-phase formation. Hosts of the general formula AB2 can accommodate, as guests, in the form of solid solutions, oxides and/or fluorides with different structures. Characteristically, the mean statistical cation-radius lies between 0.55 and 0.98 Å, with single radii between 0.46 and 0.98 Å. Relative quantities are so chosen that the cation to anion ratio of 1:2 prescribed by the host lattice, as well as electroneutrality, is maintained.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 15
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 1 (1962), S. 80-88 
    ISSN: 0570-0833
    Keywords: Oxidation ; Palladium ; Catalysis ; Alkenes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The oxidation of olefins to carbonyl compounds with palladium compounds, especially the oxidation of ethylene to acetaldehyde, is at present carried out on a technical scale. The reaction takes place via a palladium-olefin complex, the formation of which is inhibited by halide ions. Hydrolysis to the carbonyl compound is inhibited by hydrogen ions. The knowledge gained by studying the reaction of olefins with pure solutions of palladium salts allows important conclusions to be drawn concerning the action of technical catalyst solutions containing copper and palladium chloride.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 16
    ISSN: 0570-0833
    Keywords: Azo dyes ; Dyes/Pigments ; Oxidative coupling ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New findings in the field of oxidative coupling reactions are reported. These involve: extension of this type of reaction to amidrazone system displaying (vinylogous) tautomerism and to unsymmetrical diarylhydrazines; elucidation of the coupling mechanism for these arylhydrazines and for the amidrazone systems previously described; the properties of some dyes, complexed with heavy metals, and the synthesis of tetraazapentamethine and penta-azapentamethine dyes.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 17
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 1 (1962), S. 532-537 
    ISSN: 0570-0833
    Keywords: Polyacrylonitrile ; Fibers ; Azatrimethinecyanines ; Dyes/Pigments ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Like all basic dyes, azatrimethinecyanines possess a good dyeing affinity for acrylic fibers. Compounds with isolated nitrogen atoms in the trimethine chain show insufficient light fastness, whereas good to excellent fastness to light is displayed by compounds having neighboring nitrogen atoms in the chain. Thus, a working hypothesis stating that the light fastness of trimethinecyanines on acrylic fibers is improved by progressive replacement of methine groups by nitrogen atoms has been partially confirmed.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 18
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 1 (1962), S. 568-572 
    ISSN: 0570-0833
    Keywords: Trichloropyrimidyl dyes ; Dyes/Pigments ; Dichloropyrimidyl dyes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several examples are used to show that the reactivity of dichloro- and trichloropyrimidyl dyes and the sensitivity of their dyeings to hydrolysis are determined by the nature of the bridge unit between the chromophore and the reactive system. The tendency of the dyeings to hydrolyze in acid and, more particularly, in alkaline media increases with increasing reactivity of the dyes. In alkaline media, dyeings made with dyes containing oxygen bridges are cleaved mainly between the reactive system and the chromophore, while in dyeings made with dyes containing imino or methylimino bridges, the linkage between the reactive system and the cellulose is hydrolyzed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...