Waste gas treatment and methyl mercaptan recycling process in cimetidine and ranitidine production
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A technology of ranitidine and cimetidine, which is applied in the field of waste gas treatment and methyl mercaptan recovery technology, can solve the problems of chemical production safety hazards, burnout of incinerators, air pollution, etc., achieve circular economy and avoid waste gas Emissions, the effect of increasing economic benefits
Inactive Publication Date: 2015-01-07
SHANDONG WEIZHEN TEST & ANALYSIS
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However, the method of incineration has two disadvantages: on the one hand, the combustion value of methyl mercaptan gas and methyl sulfide gas is relatively high, and a flame of several meters is generated during combustion, and the heat generated at the same time is easy to burn out the incinerator, which has serious consequences for the safety of chemical production. On the other hand, the combustion method cannot fundamentally solve the odor problem, and the air pollution situation is still severe. This
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Embodiment 1
[0031] Taking the production of cimetidine technical in a pharmaceutical factory as an example, a total of 35 kg of waste gas is produced per hour during the condensation and amination process, so the daily waste gas is 840 kg, and the waste gas contains 96.0% of methyl mercaptan in terms of mass percentage. Dimethyl sulfide 2.0%, monomethylamine 1%, carbon disulfide 1%.
[0032] Such as figure 1 As shown, it is used for waste gas treatment and methyl mercaptan recovery device, including a water washing tank 2, an alkali washing tank 3, a primary absorption tank 4, a secondary absorption tank 5 and a tertiary absorption tank 6 connected in sequence through pipelines. The inlet end of the tank 2 is connected with the mechanical vacuum pump 1 through a pipeline, and the waste gas is introduced into the washing tank 2 through the mechanical vacuum pump 1; the upper ends of the primary absorption tank 4, the secondary absorption tank 5 and the tertiary absorption tank 6 are Link ...
Embodiment 2
[0045] A chemical factory produces 1-methylamino-1-methylthio-2-nitroethylene, an intermediate of ranitidine, and produces 20 kg of waste gas per hour, so the daily waste gas is 480 kg. The waste gas contains Methyl mercaptan 97.0%, dimethyl sulfide 1.5%, monomethylamine 1%, carbon disulfide 0.5%.
[0046] The equipment used for waste gas treatment and methyl mercaptan recovery is the same as in Example 1.
[0047] The specific treatment process is as follows:
[0048] (1) The exhaust gas from the workshop is sucked and collected through the intake pipe of the mechanical vacuum pump, and then pressurized through the exhaust pipe into the treatment and absorption section, and the mechanical impurities in the gas are filtered out at the front end of the suction pipe;
[0049] (2) Waste gas is introduced in the washing tank, and the control pressure is 0.3MPa, and the temperature of water in the washing tank is 10°C, and the volatile substance monomethylamine easily soluble in w...
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Abstract
The invention discloses a waste gas treatment and methyl mercaptan recycling process in cimetidine and ranitidine production. The waste gas treatment and methyl mercaptan recycling process comprises the following steps: (1) introducing waste gas in the production process of cimetidine and ranitidine into a washing tank, controlling pressure to 0.2-0.3MPa, removing volatile substances which are low in boiling point and easily soluble in water in the waste gas; (2) introducing the waste gas subjected to washing treatment into an alkaline washing tank, controlling pressure to 0.2-0.3MPa, removing volatile substances which are insoluble in water and soluble in alkaline by alkaline liquor in the alkaline washing tank; (3) introducing the waste gas subjected to the alkaline washing into a three-stage absorbing device, removing methyl mercaptan in the waste gas to generate sodium thiomethoxide; and (4) introducing the waste gas subjected to the three stages of absorption into a hydrogen peroxide falling film absorbing tower for performing oxidation treatment, and then discharging. According to the waste gas treatment and methyl mercaptan recycling process, useful chemical raw materials in the waste gas are recycled on the basis of solving the problem of waste gas emission, and thus the waste gas is prevented from being discharged, the economic benefit is increased, a new value is created, and the recycling economy is realized. The waste gas treatment and methyl mercaptan recycling process is good in application prospect.
Description
technical field [0001] The invention relates to a waste gas treatment and methyl mercaptan recovery process in the production of cimetidine and ranitidine, belonging to the technical field of energy saving and environmental protection. Background technique [0002] Cimetidine (Cimetidine) and ranitidine (Ranitidine) are currently the most widely used drugs for the treatment of ulcer disease. Developed by the British company Glaxo. It was synthesized by British Price in 1976, and its pharmacology was clarified by Bradshaw in 1979. In 1980, Berstad reported that it was effective for duodenal ulcer. Apps in hundreds of countries. [0003] The wide application of cimetidine and ranitidine in the treatment of gastric diseases will inevitably promote the continuous mass production of raw materials. However, in the production process of raw materials, methyl mercaptan, methyl sulfide, monomethylamine, Workshop exhaust gases such as carbon disulfide and nitromethane. Methyl merc...
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