Preparation method of dimethyl disulfide

Abstract

The invention provides a preparation method of dimethyl disulfide, which comprises the following steps: adding powder sulfur into a reactor under pressurized reaction conditions, and reacting the sulfur with a liquid catalyst sodium sulfide in the reactor to generate a sodium persulfide solution; introducing impure methyl mercaptan gas to react with sodium persulfate, wherein the reaction solution is divided into an organic layer dimethyl disulfide and byproducts (dimethyl trisulfide and dimethyl polysulfide); and rectifying the dimethyl disulfide and byproducts (dimethyl trisulfide and dimethyl polysulfide) to obtain dimethyl disulfide, wherein the mixed solution of the byproducts (dimethyl trisulfide and dimethyl polysulfide) returns to the reactor to complete the circular reaction. The reaction conditions are mild, the product is insoluble in the liquid catalyst and can be easily separated, and the catalyst can be circularly used for a long time.

Description

technical field

[0001] The invention relates to a method for preparing dimethyl disulfide from impure methyl mercaptan and sulfur using a liquid catalyst. Background technique

[0002] At present, the domestic method for producing dimethyl disulfide generally uses the dimethyl sulfate method, which generates dimethyl disulfide by dripping dimethyl sulfate into the sodium persulfide solution to react with it. The production process of this method produces a large amount of waste water, which causes serious environmental pollution. At the same time, dimethyl sulfate itself is a highly toxic substance. In order to solve the deficiencies in the prior art, the present invention proposes a new method for producing dimethyl disulfide. Contents of the invention

[0003] A method of reacting impure methyl mercaptan (60%-99%) with sulfur and adopting a liquid catalyst to prepare dimethyl disulfide, specifically adding powder sulfur to the reactor under pressured reaction condition...

Examples

Embodiment 1

[0013] Fill the reactor with a liquid catalyst, the catalyst is sodium sulfide solution, the reactor is equipped with multi-layer coils or jackets, the coils at the bottom of the reactor are fed with hot water (20-90 °C), and the coils in the upper part of the reactor are respectively Pass hot water (20-90°C) and low temperature water (6-8°C) alternately. Add powder sulfur and impure methyl mercaptan (60%-99%) into the reactor at a molar ratio of 1:2-1:5. Control the temperature of the reactor at 20-90°C and the pressure at 0.03MPa-0.4MPa. Sulfur first reacts with sodium sulfide to form sodium persulfide, and then reacts with methyl mercaptan to form dimethyl disulfide and dimethyl trisulfide. , Dimethyl polysulfide mixture. After the reaction is complete, the solution will be divided into an organic layer and an inorganic layer. The upper layer is an organic layer, mainly a mixture of dimethyl disulfide, dimethyl trisulfide and dimethyl polysulfide. After the organic layer ...

Embodiment 2

[0015] Fill the reactor with a liquid catalyst, the catalyst is sodium sulfide solution, the reactor is equipped with multi-layer coils or jackets, the bottom coil of the reactor is fed with hot water (90 ° C), and the upper coils of the reactor are respectively fed into Hot water (65°C) and low temperature water (8°C) are distributed alternately. Add powder sulfur and impure methyl mercaptan (65%) into the reactor at a molar ratio of 1:4.6. Control the temperature of the reactor at 58°C and the pressure at 0.25MPa. Sulfur first reacts with sodium sulfide to generate sodium persulfide, and then reacts sodium persulfide with methyl mercaptan to generate dimethyl disulfide, dimethyl trisulfide, and dimethyl polysulfide. sulfur mixture. Others are the same as embodiment 1.

Embodiment 3

[0017] Fill the reactor with a liquid catalyst, the catalyst is sodium sulfide solution, the reactor is equipped with multi-layer coils or jackets, the bottom coil of the reactor is fed with hot water (45°C), and the upper coils of the reactor are respectively fed Hot water (78°C) and low temperature water (6°C) are distributed alternately. Add powder sulfur and impure methyl mercaptan (78%) into the reactor at a molar ratio of 1:2.2. Control the temperature of the reactor at 65°C and the pressure at 0.15MPa. Sulfur first reacts with sodium sulfide to generate sodium persulfide, and then reacts sodium persulfide with methyl mercaptan to generate dimethyl disulfide, dimethyl trisulfide, and dimethyl polysulfide. sulfur mixture. Others are the same as embodiment 1.

technical field

[0001] The invention relates to a method for preparing dimethyl disulfide from impure methyl mercaptan and sulfur using a liquid catalyst. Background technique

[0002] At present, the domestic method for producing dimethyl disulfide generally uses the dimethyl sulfate method, which generates dimethyl disulfide by dripping dimethyl sulfate into the sodium persulfide solution to react with it. The production process of this method produces a large amount of waste water, which causes serious environmental pollution. At the same time, dimethyl sulfate itself is a highly toxic substance. In order to solve the deficiencies in the prior art, the present invention proposes a new method for producing dimethyl disulfide. Contents of the invention

[0003] A method of reacting impure methyl mercaptan (60%-99%) with sulfur and adopting a liquid catalyst to prepare dimethyl disulfide, specifically adding powder sulfur to the reactor under pressured reaction condition...

Examples

Embodiment 1

[0013] Fill the reactor with a liquid catalyst, the catalyst is sodium sulfide solution, the reactor is equipped with multi-layer coils or jackets, the coils at the bottom of the reactor are fed with hot water (20-90 °C), and the coils in the upper part of the reactor are respectively Pass hot water (20-90°C) and low temperature water (6-8°C) alternately. Add powder sulfur and impure methyl mercaptan (60%-99%) into the reactor at a molar ratio of 1:2-1:5. Control the temperature of the reactor at 20-90°C and the pressure at 0.03MPa-0.4MPa. Sulfur first reacts with sodium sulfide to form sodium persulfide, and then reacts with methyl mercaptan to form dimethyl disulfide and dimethyl trisulfide. , Dimethyl polysulfide mixture. After the reaction is complete, the solution will be divided into an organic layer and an inorganic layer. The upper layer is an organic layer, mainly a mixture of dimethyl disulfide, dimethyl trisulfide and dimethyl polysulfide. After the organic layer ...

Embodiment 2

[0015] Fill the reactor with a liquid catalyst, the catalyst is sodium sulfide solution, the reactor is equipped with multi-layer coils or jackets, the bottom coil of the reactor is fed with hot water (90 ° C), and the upper coils of the reactor are respectively fed into Hot water (65°C) and low temperature water (8°C) are distributed alternately. Add powder sulfur and impure methyl mercaptan (65%) into the reactor at a molar ratio of 1:4.6. Control the temperature of the reactor at 58°C and the pressure at 0.25MPa. Sulfur first reacts with sodium sulfide to generate sodium persulfide, and then reacts sodium persulfide with methyl mercaptan to generate dimethyl disulfide, dimethyl trisulfide, and dimethyl polysulfide. sulfur mixture. Others are the same as embodiment 1.

Embodiment 3

[0017] Fill the reactor with a liquid catalyst, the catalyst is sodium sulfide solution, the reactor is equipped with multi-layer coils or jackets, the bottom coil of the reactor is fed with hot water (45°C), and the upper coils of the reactor are respectively fed Hot water (78°C) and low temperature water (6°C) are distributed alternately. Add powder sulfur and impure methyl mercaptan (78%) into the reactor at a molar ratio of 1:2.2. Control the temperature of the reactor at 65°C and the pressure at 0.15MPa. Sulfur first reacts with sodium sulfide to generate sodium persulfide, and then reacts sodium persulfide with methyl mercaptan to generate dimethyl disulfide, dimethyl trisulfide, and dimethyl polysulfide. sulfur mixture. Others are the same as embodiment 1.

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