A kind of method for preparing 2-mercaptoethanol from sodium hydrosulfite production waste liquid
A technology of mercaptoethanol and hydrosulfite is applied in the field of preparing 2-mercaptoethanol from hydrosulfite production waste liquid, which can solve the problems of incomplete classification and recovery of waste liquid and the like
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Embodiment 1
[0016] A method for preparing 2-mercaptoethanol from sodium hydrosulfite production waste liquid, comprising the steps of:
[0017] 1) Put the waste liquid from sodium hydrosulfite production into a stirring tank, and start stirring to form a stable liquid after heating up to 50°C;
[0018] 2) Boost the pressure to 0.25MPa, slowly add a sodium hydroxide solution with a concentration of 38wt% under stirring, control the pH of the reaction solution between 8.5-10.0, and stop stirring for 30 minutes after reacting for 90 minutes;
[0019] 3) Rectify the reaction solution in a rectification tower with a vacuum degree of 30KPa, control the temperature of the tower tank to 159°C, and the temperature of the tower top to 75°C, cool the outlet gas from the tower top with circulating water, and then pass through -10°C brine Condensed by the condenser, the condensate is 2-mercaptoethanol with a purity of 98.7%. The residual liquid at the bottom of the tower is evaporated and concentrated...
Embodiment 2
[0021] A method for preparing 2-mercaptoethanol from sodium hydrosulfite production waste liquid, comprising the steps of:
[0022] 1) Put the waste liquid from sodium hydrosulfite production into a stirring tank, and start stirring to form a stable liquid after heating up to 52°C;
[0023] 2) Boost the pressure to 0.2MPa, slowly add a sodium hydroxide solution with a concentration of 32wt% under stirring, control the pH of the reaction solution between 8.5-10.0, and stop stirring for 30 minutes after reacting for 90 minutes;
[0024] 3) Rectify the reaction solution in a rectification tower with a vacuum degree of 40KPa, control the temperature of the tower tank to 158°C, and the temperature of the tower top to 73°C, cool the gas from the top of the tower with circulating water, and then pass through -12°C brine Condensed by the condenser, the condensate is 2-mercaptoethanol with a purity of 98.3%. The residual liquid at the bottom of the tower is evaporated and concentrated,...
Embodiment 3
[0026] A method for preparing 2-mercaptoethanol from sodium hydrosulfite production waste liquid, comprising the steps of:
[0027] 1) Put the sodium hydrosulfite production waste liquid into a stirring tank, and start stirring to a stable liquid after heating up to 55°C;
[0028] 2) Boost the pressure to 0.15MPa, slowly add a sodium hydroxide solution with a concentration of 25wt% under stirring, control the pH of the reaction solution between 8.5-10.0, and stop stirring for 30 minutes after reacting for 90 minutes;
[0029] 3) Rectify the reaction liquid in a rectification tower with a vacuum degree of 50KPa, control the temperature of the tower tank to 157°C, and the temperature of the tower top to 70°C, cool the gas from the top of the tower with circulating water, and then pass through -15°C brine The condenser condenses, and the condensate is 2-mercaptoethanol with a purity of 99.1%. The residue at the bottom of the tower is evaporated and concentrated, washed with metha...
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