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  • 1
    Electronic Resource
    Electronic Resource
    Tendencies of aromatization in steam cracking of hydrocarbons (1987)
    s.l. : American Chemical Society
    Industrial & engineering chemistry research 26 (1987), S. 2393-2397 
    Details
    ISSN: 1520-5045
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ie00071a037
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  • 2
    Electronic Resource
    Electronic Resource
    On the Thermal Cycloisomerization of 1-Vinylnaphthalene to acenaphthene. A mechanistic D-labeling study (1994)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 336 (1994), S. 415-420 
    Details
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Unlabeled 1-vinylnaphthalene (1) as well as positionally D-labeled 1 have been prepared and subjected to gas phase pyrolysis at low partial pressures of the educt compounds in nitrogen. At 700°C, 1 rearranges exclusively to acenaphthene (2). Under the conditions applied a significant H-D-exchange in the 1-vinylnaphthalene as well as in the formed acenaphthene takes place. The results obtained in this way and those resulting from pyrolysis in hydrogen (instead of nitrogen) show that despite the very high degree of dilution the high selectivity of cycloisomerization from 1 to 2 is firstly controlled by H-atom driven radical chain processes, in which the cyclization of the 2-naphthylethylradical dominates the reaction course.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19943360506
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  • 3
    Electronic Resource
    Electronic Resource
    Einfluß der Frequenz und Leistung auf die Aquasonolyse von EthernVortrag auf der GVC-Jahrestagung, 30. Sept./2. Okt.; 1998 in Freiburg. (1999)
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 71 (1999), S. 729-732 
    Details
    ISSN: 0009-286X
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cite.330710717
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  • 4
    Electronic Resource
    Electronic Resource
    Koksbildung in überhitzten Randschichten - Untersuchungen in einem neuen Ringspaltreaktor mit radialem Temperaturgefälle (1997)
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 69 (1997), S. 662-666 
    Details
    ISSN: 0009-286X
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cite.330690511
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  • 5
    Electronic Resource
    Electronic Resource
    On the Thermal Cycloisomerization of Long-Chain Alkylacetylenes in the Gas Phase (1989)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 122 (1989), S. 715-719 
    Details
    ISSN: 0009-2940
    Keywords: Alkyne ; Carbene ; Cycloisomerization ; Pyrolysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Über die thermische Cycloisomerisierung langkettiger Alkylacetylene in der GasphaseDie thermische Cycloisomerisierung einiger Alkylacetylene wurde in einem Laborrohrreaktor aus Quarzglas untersucht. 1-Hexin (1) wird dabei durch 1,2-H-Verschiebung und 1,5-C,H-Insertion des intermediär gebildeten Pentylidencarbens (vgl. Schema 1) in 3-Methyl-1-cyclopenten (5) umgelagert. 5-Methyl-1-hexin (2) reagiert analog; es entsteht 3,3-Dimethyl-1-cyclopenten (6). Im Gegensatz zur Bildung von in 3-Stellung methylierten Cyclopentenen aus 1-Alkinen ensteht aus 2-Hexin (3) 1-Methyl-1-cyclopenten (7). Offenbar ist die Acetylen-Vinyliden-Umlagerung nicht auf 1,2-H-Verschiebung beschränkt. Der Mechanismus der Cycloisomerisierung von Alkylacetylenen wird durch Untersuchungen mit D-markierten Alkinen bestätigt. Die Ergebnisse lassen den Schluß zu, daß die Cycloisomerisierung ohne weiteres mit dem überwiegend nach einem Radikalketten-Mechanismus verlaufenden thermischen Zerfall konkurrieren kann.
    Notes: The thermal cycloisomerization of some alkylacetylenes was investigated in a tubular quartz reactor. At 570°C 1-hexyne (1) rearranges to 3-methyl-1-cyclopentene (5) with a selectivity of about 27 by a reaction sequence including an acetylene-vinylidene rearrangement and 1,5-C,H insertion of the intermediately formed alkylidenecarbene species. 5-methyl-1-hexyne (2) behaves analogously forming 3,3-dimethyl-1-cyclopentene (6), while 2-hexyne (3) provides 1-methyl-1-cyclopentene (7) indicating that the acetylene-vinylidene rearrangement is obviously not restricted to 1,2-H shifts. The mechanism of the cycloisomerization of alkylacetylenes is investigated by means of D-labeled parent alkynes. The results show that the unimolecular cycloisomerization via alkylidenecarbenes obviously can be an important channel despite the dominance of a radical chain course.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19891220419
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  • 6
    Electronic Resource
    Electronic Resource
    Zur Gasphasenpyrolyse von 2-Ethinyl-1,3-butadien und dessen thermischer Cycloisomerisierung (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1375-1380 
    Details
    ISSN: 0009-2940
    Keywords: Cross-conjugated alkynes ; Alkadienynes ; Pyrolysis, gas-phase ; Cycloisomerization ; Vinylidenecarbenes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On the Gas-Phase Pyrolysis of 2-Ethinyl-1.3-butadiene and Its Thermal CycloisomerizationThe gas-phase pyrolysis of 2-ethinyl-1,3-butadiene (2) has been investigated in the 500-to-700°C temperature range. Besides several fragmentation products (≤C4 hydrocarbons) benzene and fulvene (5) are the main products. Under the same conditions 2-([2-D1]ethinyl)-1,3-butadiene (2a) furnishes the monodeuteriofulvenes 5a-c. The cycloisomerization of 2/2a presumably begins with an acetylene-vinylidenecarbene rearrangement, which may be followed by a deuterium scrambling mechanism involving either benzvalene (9) or vinylcyclobutadiene (10) intermediates. When 1-ethinyl-1-cyclohexene (6) is employed as a precursor for 2, styrene is produced in significant amounts besides the products observed from 2. Pyrolysis of 1-([2-D1]ethinyl)cyclohexene (6a) provides [D1]-styrene whose isotopic label is scrambled over both the vinyl substituent and the aromatic nucleus.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230629
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  • 7
    Electronic Resource
    Electronic Resource
    Zur Gasphasenpyrolyse von 6-alkylierten Pentafulvenen (1988)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 121 (1988), S. 1855-1860 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Gas-Phase Pyrolysis of 6-Alkylated PentafulvenesGas-phase pyrolysis of the 6-alkylfulvenes 1-3 results in an isomerization process providing the corresponding alkyl aromatics. In addition, monocyclic aromatics with C numbers smaller than those of the starting fulvenes are formed. At temperatures 〈500°C 2 reacts almost exclusively to the isopropenylcyclopentadienes 4 and 5. At higher temperatures the isomerization to the isomeric xylenes is favored (propably on a route including the tautomeric dimethylbenzvalenes). At 575°C the resulting yield ratio of o:m:p was determined to be 1:3.7:1. Toluene is the dominant aromatic side product from 2. It is formed predominantly from 4 and 5 (which are closely connected with 2 by isomerization steps) by a radical process. Cyclopentadienylvinyl and vinylcyclopentadienyl radicals are supposed to be essential radical intermediates.
    Notes: Aus den 6-Alkylfulvenen 1-3 entstehen bei der Gasphasenpyrolyse mit hoher Selektivität die isomeren Alkylaromaten sowie Einkernaromaten mit jeweils geringeren C-Zahlen. Bei Temperaturen bis 500°C werden aus 2 nahezu ausschließlich die beiden Isopropenylcyclopentadiene 4 und 5 gebildet, Temperaturen 〈500°C begünstigen die Isomerisierung zu den isomeren Xylolen (vermutlich über die tautomeren Dimethylbenzvalene); ihr Verhältnis wurde bei 575°C zu o:m:p = 1:3.7:1 ermittelt. Toluol ist das vorherrschende aromatische Nebenprodukt aus 2. Seine Bildung erfolgt über einen Radikalprozeß vorzugsweise aus den mit 2 im Isomerisierungsverbund stehenden 4 und 5. Als Intermediate werden Cyclopentadienylvinyl- und Vinylcyclopentadienyl-Radikale angenommen.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19881211026
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  • 8
    Electronic Resource
    Electronic Resource
    Pyrolysis Kinetics of OctalinsDedicated to Prof. Dr. Gerhard Reinisch on the occasion of his 60th birthday (1990)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 332 (1990), S. 547-550 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The gas phase pyrolysis of three octalins has been studied in a conventional flow system in the temperature range between 500 and 725°C and at pressures up to 70 Torr (educt) and 1 atm (reaction system), respectively. The reactions follow a first-order rate law. The overall rate coefficients are given by the following Arrhenius parameters. 9(10)-octalin (1): log k1 (s-1) = (14.71 ± 1.6) - (260.0 ± 6.2) kJ mol-1/2.303 RT; 1(9)-octalin (2): log k2 (s-1) = (13.62 ± 0.9) - (239.1 ± 3.7) kJ mol-1/2.303 RT; trans-1-octalin (3): og k3 (S-1) = (14.76 ± 0.5) - (272.6 ± 1.8) kJ mol-1/ 2.303 RT. The mechanism of the thermal degradation of 1 to 3 is related to Retro-Diels-Alder fragmentation.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19903320420
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  • 9
    Electronic Resource
    Electronic Resource
    Über 1,2-Umlagerungen und C—H-Einschubreaktionen Acyclischer AlkylidencarbeneHerrn Prof. Dr. Dr. H. G. O. Becker zum 65. Geburtstag gewidmet (1987)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 329 (1987), S. 49-54 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On 1.2-Shift Reactions and C—H-Insertions of Acyclic Alkylidene CarbenesTwo series of acyclic terminal vinyl bromides (1…4 and 5…7) were tested in the reaction with potassium tert-butoxide as precursors of alkylidene carbenes. As expected 1 up to 4 only give 1-alkynes whereas the 2-methylated vinyl bromides 5, 6 and 7 yield 1-methylated cyclopentenes predominantly besides 2-alkynes. The formation of cyclopentenes indicates a reaction route via alkylidene carbenes and 1,5-C—H-insertion reactions, that of 2-alkynes is convincing evidence for 1,2-alkyl shift reactions in 2-methyl substituted alkylidene carbenes. The selectivity of 1,5-C—H-insertion depends on the degree of alkyl substitution of the C-5-atom. At 240°C the selectivity is 1°:2°:3° ≈ 1:54:240.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19873290107
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