Rubber, Polyisoprenes and Allied Compounds. VIII. The Formation of Dialkyl Sulfide Dihalides, and Its Bearing on the Problem of Determining the Unsaturation of Vulcanized Rubber

1946 ◽  
Vol 19 (2) ◽  
pp. 287-295
Author(s):  
George F. Bloomfield
Keyword(s):  
Zinc Oxide ◽  
Acetic Acid ◽  
Double Bond ◽  
Potassium Iodide ◽  
Sulfur Atom ◽  
Iodine Monochloride ◽  
Vulcanized Rubber ◽  
Dialkyl Sulfide ◽  
Dialkyl Sulfides ◽  
Halogen Acid

Abstract In determining the unsaturation of olefinic sulfides and disulfides by halogenation methods, the addition of halogen to the sulfur atom must be taken into account. The dihalides of dialkyl or dialkenyl sulfides react with aqueous potassium iodide partly to liberate iodine with regeneration of the sulfide, and partly to form halogen acid and dialkyl or dialkenyl sulfoxides. Correction for the latter reaction, which occurs extensively in the presence of alcohol or acetic acid, must be applied before reliable unsaturation values for dialkenyl sulfides can be obtained. With vulcanized rubber and iodine monochloride, the precise magnitude of the correction to be applied is uncertain, but this uncertainty can be removed by using bromine as the additive reagent. Simple rubber-sulfur vulcanizates show a loss of unsaturation corresponding to one double bond per sulfur atom combined up to at least 8 per cent of combined sulfur; vulcanizates accelerated with mercaptobenzothiazole in the presence of zinc oxide exhibit a substantially smaller loss of unsaturation. The dibromides of dialkyl sulfides readily yield a molecule of bromine to olefins, the reaction being practically exclusively additive.

Sulfur Bond in Vulcanizates Implications of Halogen Reactions

1947 ◽  
Vol 20 (3) ◽  
pp. 627-648
Author(s):  
S. R. Olsen ◽  
C. M. Hull ◽  
Wesley G. France
Keyword(s):  
Double Bond ◽  
Carbon Tetrachloride ◽  
Sulfur Atom ◽  
Side Reactions ◽  
Double Bonds ◽  
Vulcanized Rubber ◽  
Iodine Chloride ◽  
Allyl Sulfide ◽  
Sulfur Bond

Abstract 1. When iodine chloride is used for the determination of double bonds in sulfur-vulcanized rubber or GR-S, it undergoes side reactions induced by combined sulfur. 2. Bromine in carbon tetrachloride is believed to give a satisfactory measure of the double bonds in a rubber-sulfur vulcanizate dissolved in dichlorobenzene-chloroform mixture. 3. The relation of one double bond consumed per sulfur atom combined in the rubber-sulfur type vulcanizate was confirmed. 4. Organic accelerators (in the absence of metal activators) catalyze the combination of sulfur without altering the ratio of one double bond loss per sulfur atom combined. 5. The introduction of a metal oxide or soap, such as zinc, causes a different type of vulcanization, which results in less than one double bond consumed per sulfur atom combined. 6. The reactions of propyl sulfide, dodecyl sulfide, propyl disulfide, allyl sulfide, methallyl sulfide, and butylmethallyl sulfide with iodine chloride and with bromine, respectively, are described. 7. The behavior of rubber-sulfur vulcanizates resembles that of butylmethallyl sulfide in reactions with iodine chloride and bromine, respectively; this suggests an alkyl-allyl type sulfur bond. 8. The theory of vulcanization proposed by Armstrong, Little, and Doak, based on the α-methylenic concept of Farmer, is supported by the findings of this investigation.

The Reaction of Sulfur and Sulfur Compounds with Olefinic Substances. V. Rubber Vulcanization

1948 ◽  
Vol 21 (3) ◽  
pp. 543-552
Author(s):  
G. F. Bloomfield
Keyword(s):  
Zinc Oxide ◽  
Hydrogen Sulfide ◽  
Double Bond ◽  
Sulfur Atom ◽  
Small Proportion ◽  
Sulfur Compounds ◽  
Cross Linking ◽  
Inhibiting Effect ◽  
Mercapto Groups ◽  
Soluble Zinc

Abstract Data presented for a range of vulcanized rubbers prepared under different conditions show that, while olefinic unsaturation becomes reduced by vulcanization in the proportion of one double bond for each sulfur atom combined with a C5H8 unit, the original H/C ratio of 8/5 is not altered. The loss of unsaturation is somewhat modified when zinc oxide or certain accelerators also are present. Oxygen has a slight inhibiting effect on vulcanization; hydrogen sulfide and thiols markedly catalyse the vulcanization reaction without, apparently, affecting the efficiency of the sulfur cross-linking reaction. In confirmation of the results of Hull, Olsen, and France, a small proportion of zinc oxide or a soluble zinc soap promotes a reaction between sulfur and mercapto groups whereby di- and polysulfides are formed with liberation of hydrogen sulfide. The same type of activity is shown by some of the nitrogenous accelerators commonly used in rubber vulcanization. Substantial conversion of mercapto groups into polysulfide linkages is, therefore, to be expected when vulcanization is conducted in the presence of these auxiliary substances.

Synthesis and properties of 1,3-bis(4-nitrophenyl)-1-butene

1980 ◽  
Vol 45 (7) ◽  
pp. 2120-2124 ◽  
Author(s):  
Gabriel Čík ◽  
Anton Blažej ◽  
Kamil Antoš ◽  
Igor Hrušovský
Keyword(s):  
Acetic Acid ◽  
Nitric Acid ◽  
Double Bond ◽  
Fuming Nitric Acid

1,3-Bis(4-nitrophenyl)-1-butene was prepared by nitration of 1,3-diphenyl-1-butene (I) with fuming nitric acid in acetic acid. The double bond in I was protected by addition of bromine which was eliminated after the nitration. The UV, IR and 1H- spectra of the synthesized compounds are interpreted.

Reaction of 30-nor-18-lupene derivatives with bromine and peracids

1984 ◽  
Vol 49 (1) ◽  
pp. 141-149
Author(s):  
Eva Klinotová ◽  
Jiří Protiva ◽  
Jiří Klinot ◽  
Alois Vystrčil
Keyword(s):  
Acetic Acid ◽  
Double Bond

The reaction of diol I and diacetate IIwith one mole of bromine gives rise, depending on conditions, to isomeric dienes III-V and IX or to derivatives substituted in position 21 (VII, VIII). On reaction of diacetate II with two moles of bromine in acetic acid 21,22-disubstituted compounds XI and XII were obtained. Diene V is the intermediate in the formation of dienes IV and IX and derivatives XI and XII. Epoxidation of the 18(19)-double bond in compounds I and II takes place from the β-side and leads for epoxides XIV and XV.

Reducing Pathogens by Using Zinc Oxide Nanoparticles and Acetic Acid in Sheep Meat

2014 ◽  
Vol 77 (9) ◽  
pp. 1599-1604 ◽  
Author(s):  
MAHBOUBEH MIRHOSSEINI ◽  
VAHID ARJMAND
Keyword(s):  
Zinc Oxide ◽  
Antibacterial Activity ◽  
Acetic Acid ◽  
Zno Nanoparticles ◽  
Pathogenic Bacteria ◽  
Inhibitory Effect ◽  
Initial Growth ◽  
Practical Applications ◽  
E Coli ◽  
Sheep Meat

Practical applications of different concentrations (0, 1, 2, 4, 6, and 8 mM) of zinc oxide (ZnO) suspensions containing 1% acetic acid were investigated against the pathogenic bacteria Listeria monocytogenes, Escherichia coli, Staphylococcus aureus, and Bacillus cereus. ZnO suspensions (0, 1, 3, 6, and 8 mM) containing acetic acid had a significant inhibitory effect on the growth of L. monocytogenes, E. coli, and S. aureus during 12 h of incubation, and the 8 mM suspensions of ZnO were the most effective against all the strains. These data suggested that the antibacterial activity of ZnO was concentration dependent. Thus, 6 and 8 mM ZnO were selected for further studies in meat. ZnO nanoparticles reduced initial growth of all inoculated strains in meat. To our knowledge, this is the first report describing the antibacterial activity of ZnO nanoparticles in meat and indicates the potential of these nanoparticles as an antibacterial agent in the food industry.

Silver nanoparticles in combination with acetic acid and zinc oxide quantum dots for antibacterial activities improvement—A comparative study

2014 ◽  
Vol 311 ◽  
pp. 659-665 ◽  
Author(s):  
Sofiane Sedira ◽  
Ahmed Abdelhakim Ayachi ◽  
Sihem Lakehal ◽  
Merouane Fateh ◽  
Slimane Achour
Keyword(s):  
Quantum Dots ◽  
Silver Nanoparticles ◽  
Zinc Oxide ◽  
Acetic Acid ◽  
Comparative Study ◽  
Antibacterial Activities

Contributions to the Analysis of Rubber. I. Determination of the Water-Soluble Components of Rubber

1937 ◽  
Vol 10 (3) ◽  
pp. 574-583
Author(s):  
P. Dekker
Keyword(s):  
Acetic Acid ◽  
Acid Reflux ◽  
Water Soluble ◽  
Hot Water ◽  
Water Bath ◽  
Vulcanized Rubber ◽  
Magnesium Compounds ◽  
Calcium Compounds ◽  
Soluble Components

Abstract 1. It is shown that the methods which are ordinarily used for determining water-soluble substances in raw rubber give low results, and are quite useless for vulcanized rubber. 2. New analytical procedures are developed for determining the water-soluble substances in raw rubber and in vulcanized rubber. These procedures are carried out in the following manner. (a) Raw Rubber.—Heat 2 grams of rubber in 80 cc. of xylene and 5 cc. of acetic acid on a water bath until the rubber is completely dissolved, add 5 cc. of acetic acid and 10 cc. of water, heat for 3–4 hours on the water bath with frequent agitation, transfer to a distilling flask (rinsing the first flask with 50 cc. of hot water), distill the xylene with steam, filter the residual solution, evaporate the filtrate on a water bath; and dry at 100° C. (b) Vulcanized Rubber and Rubber Mixtures.—First extract the sample with acetone, heat 2 grams of the acetone-extracted sample with 80 cc. of xylene on a water bath, add 5 cc. of acetic acid, reflux the mixture on an oil bath, after complete dissolution add 5 cc. of acetic acid and 10 cc. of water, heat the solution for 2 hours on an oil bath at 110–120° C., distill the xylene, as in the determination with raw rubber, filter the residue, evaporate the filtrate to dryness, take up the residue in 50 cc. of water, pass a current of hydrogen sulfide through the solution for 10 minutes to precipitate zinc as sulfide, filter, evaporate the filtrate, and dry the residue at 100° C. 3. In the presence of calcium compounds, magnesium compounds, glue and textiles, the method gives false results. Modifications of the method are therefore recommended, whereby these substances are eliminated.

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