Method for preparing 2,2'-dibenzothiazyl disulfide by catalyzing oxidation through molecular oxygen
A technology of dithiodibenzothiazole and benzothiazole, which is applied in the field of 2,2'-dithiobibenzothiazole synthesis, can solve the problems of limited use, achieve less by-products, strong industrial application prospects, The effect of simple synthesis process
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Embodiment 1
[0026] Example 1: Synthesis of 2,2'-dithiodibenzothiazole (DM) by catalytic oxidation of 2-thiol benzothiazole (M) in an oxygen atmosphere
[0027] In a 500 L reactor, 30 kg M, 2.1 kg Co(NO 3 ) 2 ·6H 2 O, 2.5 kg acetylacetone and 300 L methanol; heat up to 100°C under stirring, feed oxygen, keep the pressure in the reactor at 0.15 MPa, stop the reaction after 15 hours of reaction, cool, filter, wash with 30 L methanol, wash with water, Dry to obtain product DM28.6 kg, the infrared spectrum of product is as follows figure 1 As shown, its infrared spectrum is completely consistent with the DM standard infrared spectrum, the yield is 96%, and the melting point is 180-181 ° C. According to liquid chromatography analysis, the obtained product has the same retention time as the DM standard sample, and the content is 99.5%.
[0028] The mother liquor from which DM was separated by filtration was combined with methanol recovered by washing, returned to the reactor, and 30 kg of M w...
Embodiment 2
[0030] Embodiment 2: Synthesis of DM by catalytic oxidation of M in air atmosphere
[0031] In a 500 L reactor, 60 kg M, 0.1 kg Ce(NO 3 ) 3 ·6H 2 O, 0.1 kg Mn(OAc) 2 4H 2 O and 0.1 kg 2,2,6,6-tetramethylpiperidine-N-oxyl radical and 300 L ethanol; heated to 120°C with stirring, and air was injected to keep the pressure in the reactor at 2.0 MPa, and the reaction Stop the reaction after 20 hours, cool, filter, wash with 30L of ethanol, wash with water, and dry to obtain 57.2 kg of DM, with a yield of 96% and a melting point of 180-182°C. The DM content was 99% by liquid chromatography analysis.
[0032] The mother liquor from which DM was separated by filtration was combined with ethanol recovered from washing, returned to the reactor, and 60 kg M was re-introduced without further input of catalyst. The reaction was continued for 20 hours according to the original conditions, and finally 54.9 kg DM was obtained with a yield of 92% and a melting point of 180 -181°C, the DM...
Embodiment 3
[0034] Embodiment 3: Oxygen oxidation synthesis DM under normal pressure
[0035] In a 500 L reactor equipped with a condenser and a vent pipe inserted into the bottom, put 90 kg M, 4.0 kg CuSO 4 ·5H 2 O, 0.5 kg of oxalic acid and 200 L of acetonitrile; heated to 80°C under stirring, continuously fed oxygen to start the reaction; stopped the reaction after 25 hours of reaction, cooled, filtered, washed with 90 L of acetonitrile, washed with water, and dried to obtain 84.1 kg of product DM, the yield is 94%, the melting point is 179-181°C, and the DM content is 99.4% according to liquid chromatography.
[0036]The mother liquor from which DM was separated by filtration was combined with acetonitrile recovered by washing, returned to the reactor, and 90 kg M was re-introduced without further input of catalyst. The reaction was continued for 25 hours according to the original conditions, and finally 81.4 kg DM was obtained, with a yield of 91% and a melting point of 178 -180°C,...
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