The Interaction of Sulfur and Sulfur Compounds with Olefinic Substances. VII. Low-Temperature Sulfuration of Trialkylethylenes with Hydrogen Sulfide-Sulfur Dioxide and with a Sulfur-Zinc Dithiocarbamate System

1955 ◽  
Vol 28 (2) ◽  
pp. 470-479
Author(s):  
E. H. Farmer ◽  
J. F. Ford ◽  
J. A. Lyons
Keyword(s):  
Zinc Oxide ◽  
Hydrogen Sulfide ◽  
Sulfur Dioxide ◽  
Low Temperature ◽  
Room Temperature ◽  
Cross Linking ◽  
Sulfide Sulfur ◽  
Tetramethylthiuram Disulfide ◽  
Zinc Compounds ◽  
Low Concentrations

Abstract The sulfuration of trialkylethylenes with hydrogen sulfide-sulfur dioxide at 0° C (Peachey process) results in disubstitutive cross-linking of the olefins, yielding dialkenyl tetrasulfides. At higher temperatures, substitutive-additive cross-linking occurs, and alkyl alkenyl polysulfides are formed. Dialkenyl tetrasulfides are similarly formed by causing the olefin to react with sulfur at room temperature in the presence of zinc oxide and zinc dibutyldithiocarbamate, low concentrations of hydrogen sulfide acting as a catalyst for this reaction. At higher temperatures, the reaction is also exclusively disubstitutive, a feature connected with the function of zinc compounds in influencing the cross-linking reaction. The sulfuration of olefins with tetramethylthiuram disulfide at 140° C shows a similar influence of zinc compounds.

scholarly journals Approaches towards the synthesis of a 2,9,16,23-tetrasubstituted phthalocyanine as a pure isomer

1988 ◽  
Vol 66 (5) ◽  
pp. 1059-1064 ◽  
Author(s):  
Shafrira Greenberg ◽  
A. B. P. Lever ◽  
Clifford C. Leznoff
Keyword(s):  
Hydrogen Sulfide ◽  
Low Temperature ◽  
Zinc Acetate ◽  
Room Temperature ◽  
Pure Isomer

Treatment of 4-neopentoxyphthalonitrile with hydrogen sulfide gas yielded 1-imino-6-neopentoxy-3-thioisoindoline and 1-imino-5-neopentoxy-3-thioisoindoline, which on alkylation with iodomethane gave 1-imino-3-methylthio-6-neopentoxyiso-indolenine and 1-imino-3-methylthio-5-neopentoxyisoindolenine. The methylthioisoindolenines readily condensed at room temperature to a mixture of tetrasubstituted phthalocyanines and a series of linear open-chained purple compounds characteristic of isoindigos, while condensation at −20 °C in the presence of zinc acetate gave, in at least one experiment, 2,9,16,23-tetraneo-pentoxyphthalocyanine as a pure isomer. The low temperature formation of phthalocyanines is remarkable and the syntheses described herein provide guidelines for the synthesis of pure isomers of 2,9,16,23-tetrasubstituted phthalocyanines. The purple and red compounds are shown to have isoindigo structures rather than a ring-opened phthalocyanine structure as previously reported.

scholarly journals Ozone Sensors Working at Room Temperature Using Zinc Oxide Nanocrystals Annealed at Low Temperature

Proceedings ◽  
2017 ◽  
Vol 1 (4) ◽  
pp. 423 ◽  
Author(s):  
Sandrine Bernardini ◽  
Mohamed Hameda Benchekroun ◽  
Tomas Fiorido ◽  
Khalifa Aguir ◽  
Marc Bendahan ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Low Temperature ◽  
Room Temperature

Vulcanization of Rubber Compounds

1940 ◽  
Vol 13 (4) ◽  
pp. 918-925 ◽  
Author(s):  
E. W. Booth ◽  
D. J. Beaver
Keyword(s):  
Zinc Oxide ◽  
Hydrogen Sulfide ◽  
Carbon Black ◽  
Physical Properties ◽  
Room Temperature ◽  
Appreciable Effect ◽  
Vacuum Oven ◽  
Rubber Compounds ◽  
Sulfide Content ◽  
Hydrogen Sulfide Content

Abstract 1. Rubber dissolves approximately one per cent of hydrogen sulfide when saturated at room temperature. 2. All types of commercial accelerators are retarded in rate of vulcanization as a result of treatment with hydrogen sulfide, and the retardation is directly proportional to the hydrogen sulfide content. 3. The physical properties of mercaptobenzothiazole types of accelerators and diphenylguanidine are not permanently affected by hydrogen sulfide, but dithiocarbamates, thiuram sulfides, aldehydeamines and litharge are permanently affected. 4. Rubber compounds containing mercaptobenzothiazole types of accelerators or diphenylguanidine, which have been treated with hydrogen sulfide and then degassed in a vacuum oven, show normal rate of vulcanization. Compounds containing aldehydeamines, litharge or carbon black show permanent retarding, even after degassing. 5. Increased zinc oxide or sulfur has no appreciable effect on the retardation. 6. Little or no zinc sulfide is formed as a result of treatment with hydrogen sulfide. 7. Hydrogen sulfide treatment of rubber compounds retards the rate of combination of sulfur with rubber. 8. In no case did hydrogen sulfide treatment improve the physical properties of the vulcanizate.

scholarly journals Water vapor inhibits hydrogen sulfide detection in pulsed fluorescence sulfur monitors

2016 ◽  
Vol 9 (6) ◽  
pp. 2669-2673 ◽  
Author(s):  
Anders B. Bluhme ◽  
Jonas L. Ingemar ◽  
Carl Meusinger ◽  
Matthew S. Johnson
Keyword(s):  
Hydrogen Sulfide ◽  
Water Vapor ◽  
Sulfur Dioxide ◽  
Relative Humidity ◽  
Pollution Control ◽  
Sulfide Sulfur ◽  
Molybdenum Catalyst ◽  
Air Stream ◽  
Ambient Concentrations ◽  
Converter Unit

Abstract. The Thermo Scientific 450 Hydrogen Sulfide–Sulfur Dioxide Analyzer measures both hydrogen sulfide (H2S) and sulfur dioxide (SO2). Sulfur dioxide is measured by pulsed fluorescence, while H2S is converted to SO2 with a molybdenum catalyst prior to detection. The 450 is widely used to measure ambient concentrations, e.g., for emissions monitoring and pollution control. An air stream with a constant H2S concentration was generated and the output of the analyzer recorded as a function of relative humidity (RH). The analyzer underreported H2S as soon as the relative humidity was increased. The fraction of undetected H2S increased from 8.3 at 5.3 % RH (294 K) to over 34 % at RH  >  80 %. Hydrogen sulfide mole fractions of 573, 1142, and 5145 ppb were tested. The findings indicate that previous results obtained with instruments using similar catalysts should be re-evaluated to correct for interference from water vapor. It is suspected that water decreases the efficiency of the converter unit and thereby reduces the measured H2S concentration.

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