- Method for producing thionocarbamate and dibenzyl disulfide
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The invention discloses a method for producing thionocarbamate and dibenzyl disulfide. The method comprises the following steps: carrying out an esterification reaction on alkyl xanthate and benzyl halide to obtain alkyl benzyl xanthate; carrying out an aminolysis reaction on the alkyl benzyl xanthate and fatty amine to obtain a thionocarbamate and benzyl mercaptan mixture; and carrying out an oxidation reaction on the thionocarbamate and benzyl mercaptan mixture and hydrogen peroxide, and carrying out liquid-solid separation to obtain a solid which is the dibenzyl disulfide product and a liquid, and allowing the liquid to stand for oil and water layering in order to obtain an oil phase which is the thionocarbamate product. The dibenzyl disulfide product and thionocarbamate product obtained through the method have high yield and high purity, and the method has the advantages of easiness in separation of the products in the preparation process, environmental protection, high atom economy property, low production cost, and easiness in realization of industrial production.
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Paragraph 0057-0059; 0069-0071
(2017/06/02)
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- A synthesis of N-alkyl and N,N-dialkyl O-ethyl thiocarbamates from diethyl dixanthogenate using different oxidants
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A novel synthesis of N-alkyl and N,N-dialkyl O-ethyl thiocarbamates from diethyl dixanthogenate and primary and secondary amines, using three oxidizing systems, has been developed on the laboratory scale, and the method using sodium hypochlorite has been applied on a semi-industrial scale. The effect of the oxidizing agents, sodium hypochlorite, in-situ-generated peracetic acid, and the manganese(II) acetate/oxygen system on product purity and yield was studied. The results obtained by use of these three methods were compared with those obtained by reaction of sodium ethyl xanthogenacetate and amines, and of sodium ethyl xanthate with amines in the presence of sulfated nickel zeolite catalyst. The reaction mechanism of sodium hypochlorite oxidation has been established on the basis of isolation of reaction intermediates and determination of their structure by use of Fourier-transform infrared, 1H and 13C NMR, and mass spectrometric methods. The suggested sodium hypochlorite and manganese(II) acetate/oxygen systems have many advantages in comparison with commercial and catalytically promoted synthetic methods, because they are new ecologically friendly syntheses. Springer-Verlag 2010.
- Milosavljevic, Milutin M.,Sovrlic, Milica,Marinkovic, Aleksandar D.,Milenkovic, Dragan D.
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experimental part
p. 749 - 755
(2011/07/08)
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- Identification of new, odor-active thiocarbamates in cress extracts and structure-activity studies on synthesized homologues
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New, odorant nitrogen- and sulfur-containing compounds are identified in cress extracts. Cress belongs to the botanical order Brassicales and produces glucosinolates, which are important precursors of nitrogen- and sulfur-containing compounds. Those compo
- Breme, Katharina,Fernandez, Xavier,Meierhenrich, Uwe J.,Brevard, Hugues,Joulain, Daniel
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p. 1932 - 1938
(2008/02/04)
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- The mechanisms of hydrolysis of alkyl N-alkylthioncarbamate esters at 100°C
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The hydrolysis of ethyl N-ethylthioncarbamate (ETE) at 100°C was studied in the range of 7 mol/L HCl to 4 mol/L NaOH. The pH-rate profile showed that the hydrolysis occurred through specific acid catalysis at pH 6.5. The Hammett acidity plot and the excess acidity plot against X were linear. The Bunnett-Olsen plot gave a negative slope indicating that the conjugate acid was less hydrated than the neutral substrate. It was concluded that the acid hydrolysis occurred by an Al mechanism. The neutral species hydrolyzed with general base catalysis shown by the Bronsted plot with β = 0.48 ± 0.04. Water acted as a general base catalyst with (pseudo-)first-order rate constant, kN = 3.06 × 10-7 s-1. At pH > 6.5 the rate constants increased, reaching a plateau at high basicity. The basic hydrolysis rate constant of ethyl N,N-diethylthioncarbamate, which must react by a BAc2 mechanism, increased linearly at 1-3 mol/L NaOH with a second-order rate constant, k2 = 2.3 × 10-4 (mol/L)-1 s-1, which was 10 times slower than that expected for ETE. Experiments of ETE in 0.6 mol/L NaOH with an excess of ethylamine led to the formation of diethyl thiourea, presenting strong evidence that the basic hydrolysis occurred by the E1cb mechanism. In the rate-determining step, the E1cb mechanism involved the elimination of ethoxide ion from the thioncarbamate anion, producing an isothiocyanate intermediate that decomposed rapidly to form ethylamine, ethanol, and COS.
- Humeres, Eduardo,Sanchez, Maria De Nazare,Lobato, Conceicao M. L.,Debacher, Nito A.,De Souza, Eduardo P.
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p. 1483 - 1491
(2007/10/03)
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- THE =C=S -> =C=O TRANSFORMATION USING THE SOFT NO(+)-SPECIES
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The reaction of NaNO2 in acidic solution with thiocarbonyl compounds has been studied.Secondary- and tertiary thioamides, 1-benzyl-hexahydro-2H-azepine-2-thione, 5-ethyl-5-phenyl thiobarbituric acid, certain thiourea derivatives, 2H-1-benzopyran-2-thione, O,O-diphenyl-thiocarbonic ester, O,S-diphenyl-dithiocarbonic ester, N,N-dimethyl-S-phenyl-dithiocarbamatic ester, N-ethyl-N-phenyl-O-ethyl-thiocarbamatic ester are all converted into the corresponding carbonyl-analogues. 4,4'-Bis(dimethylamino)-thiobenzophenone (Michler's thioketone) gives 3-nitro-4,4'-bis(dimethylamino)-benzophenone at room temperature.At (-10 deg C)-(-5 deg C) the expected oxo compound is obtained as the main product together with 4-(N-nitroso-methylamino)-4'-(dimethylamino)-benzophenone.
- Joergensen, K. A.,Ghattas, A.-B.A.G.,Lawesson, S.-O.
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p. 1163 - 1168
(2007/10/02)
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