Second, the reaction principle:
The most commonly used MnO2+4HCl (concentration) = = heating = = mncl2+2h2o+Cl2 =
Commonly used oxidants are KMnO4, KClO3, Ca(ClO)2, etc.
1、2 kmno 4+ 16 HCl = 2 KCl+2 mncl 2+5cl 2 ↑+ 8H2O？
Since the oxidation of KMnO4 is stronger than that of MnO2, the preparation of Cl2 from KMnO4 usually does not require heating.
2、KClO3+6HCl==== KCl+3Cl2↑+3H2O
3.Ca(ClO)2+4HCl (concentrated) = = = CaCl2+2cl2 =+2h2o?
In a word, the methods of making chlorine in the laboratory revolve around one core: chloride ion+oxidant+acidic environment. If the oxidant does not oxidize, it needs to be heated to different degrees.
3. Collect with upward exhaust method or saturated brine method.
Fourthly, HCl gas is removed with saturated salt solution and water vapor is removed with concentrated sulfuric acid.
5. Absorb the tail gas with strong alkali solution (such as NaOH solution).
Six, full inspection:
1. Put the wet starch -KI test paper near the bottle mouth of Cl2, and observe that the test paper turns blue immediately, which proves that it is full.
2. Put the wet blue litmus test paper near the bottle mouth of Cl2, and observe that the test paper first turns red and then fades, which proves that it is full.
3. When preparing chlorine gas in the laboratory, it is often judged whether it is full according to the color of chlorine gas.
Extended data:
Chlorine leakage is easy to cause personal injury and regional pollution. Methods to prevent chlorine leakage are:
1. Defective equipment and components shall not be selected, and all equipment and components shall be tested and inspected regularly;
2, strengthen the process management, strictly control the process indicators, found that the problem must be timely inspection and handling;
3. Strengthen the management and maintenance of accident chlorine treatment device. The related devices are powered by multiple power sources, the accident chlorine treatment device is cleaned regularly, and the pump is debugged regularly;
4. In order to detect chlorine leakage in time, chlorine alarms should be installed in production, storage, transportation and use positions. Once chlorine gas leaks, it can be found as early as possible to prevent the accident from expanding. TV monitoring and lye spraying devices should be installed in liquefaction posts;
5. Strengthen safety education and training for employees. ?
Emergency treatment of leakage:
People in the leaked contaminated area should be evacuated to the upwind (side) quickly and give an alarm immediately. In case of small leakage, the alert is set at 150m, and in case of large leakage, the alert is set at 450m.
Firefighters must wear air respirator or oxygen respirator, full-body fire protection and gas protection suit and rubber gloves, and dispose of them in the upwind direction. Cut off the leakage source as much as possible, ventilate reasonably, accelerate the diffusion, dilute and dissolve the sprayed water, build dikes or dig pits to accommodate a large amount of wastewater.
If possible, inject the leakage into the solution of reducing agent (acid sodium sulfate or acid sodium carbonate) by pipeline, or immerse the leaked steel cylinder in lime emulsion. Specific disposal measures are as follows:
1, close the valve and cut off the source. When chlorine gas leaks from the production plant, the engineers and technicians of the accident unit or those familiar with the process will close the pipes and valves for conveying materials, cut off the supply of materials and cut off the accident source, and the public security fire brigade will send flowers or water guns to cover and assist in the operation.
2. Pour cans and transfer. When the tank and the wall of the tank leak and the leakage cannot be prevented, liquid chlorine can be poured into other containers or storage tanks by dredging.
3. Chemical neutralization. When there is a small amount of leakage from the tank and container wall, chemical neutralization method can be used, that is, alkaline substances such as quicklime and baking soda powder are added to the water tank of the fire truck and sprayed into the tank and container to reduce the harm, or the leaked liquid chlorine can be introduced into the sodium carbonate solution for neutralization to form harmless or slightly toxic wastewater.
The specific reactions are CaO+H2O-Ca(OH)2, 2ca (OH) 2+2cl2-CaCl2+Ca (CIO) 2+2h2o. Calcium chloride and calcium hypochlorite are produced, which has no toxic effect. If the field temperature is relatively high, calcium chloride and calcium chlorate are generated. The product has good sedimentation, does not form suspended matter, quickly falls to the ground, and plays a role in calcium fertilizer for ground plants.
4. Dilute and reduce toxicity. Focusing on the leakage point, water curtain or spray water gun should be set around the tank and container wall to dilute and reduce the toxicity, but it is not advisable to use direct current water or spray it directly to the leakage point to avoid the interaction between chlorine and water to generate acid and accelerate the corrosion of the leakage point. In addition to dissolving chlorine in water, the reaction between chlorine and water can be used to increase the absorption of chlorine in the air.
5. Soak and hydrolyze. When the valve of a small liquid chlorine steel cylinder is damaged and leaked during transportation, and it cannot be stopped without a plugging device, the steel cylinder can be soaked in alkaline solution such as calcium hydroxide for neutralization, or soaked in water.
6, equipment plugging. When the pipeline wall leaks, and the leakage point is in front of the valve or the valve is damaged, and it is impossible to close the valve to stop the leakage, tools such as gaskets, sealing wedges and sealing bags with different shapes can be used for sealing.
(a) The leakage of micropores can be prevented by screwing screws and adhesives into the holes.
(b) If leakage occurs due to tearing of the tank wall, special devices such as inflatable bags and inflatable cushions can be used to seal the leakage from the outside.
(c) When the pipeline leaks under pressure, the internal and external leakage can be prevented by binding inflatable sealing belts or using special devices such as rubber pads lined with metal shells.
(d) If the valve flange or flange gasket is damaged and leaked, it can be plugged with different types of flange clamps and injected with sealant, or directly plugged with special valve plugging tools.
7. Disinfection treatment.
1, chemical disinfection method. That is, alkaline substances such as sodium hydroxide, ammonia water, sodium bicarbonate, etc. are dissolved in water, sprayed on the surface of polluted areas or polluted bodies, and undergo chemical reactions, changing the nature of poisons and becoming non-toxic or low-toxic substances;
2. Physical disinfection. That is, substances with adsorption capacity, such as adsorption pads and activated carbon, are transferred after adsorption and recovery; Toxic air can be blown away by a water-driven range hood to reduce toxicity, or the polluted area can be temporarily closed, and the toxic gas can disappear through natural conditions such as sun exposure and ventilation; It can also be diluted and attenuated by spraying water.
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