Colorless needle crystals. Easy to solve. Hydrogen sulfide is liberated at the melting point. Soluble in water and alcohol. The aqueous solution is strongly alkaline. Reacts in the presence of acid to form hydrogen sulfide. Bitter. The dye industry is used for the synthesis of organic intermediates and auxiliaries for the preparation of sulphur dyes. The leather industry is used for the depilation and tanned leather of hides. The fertilizer industry is used for the removal of monomeric sulphur from activated carbon desulfurizers. The mining industry is used in large quantities in copper mines. Mineral processing, sulphuric acid dyeing in the production of man-made fibers, etc., is a raw material for the manufacture of semi-finished products of ammonium sulphate and pesticide ethanethiol, and is also used for wastewater treatment. It is obtained by absorbing hydrogen sulfide gas from a sulfide alkali or caustic soda solution.
Appearance and traits: white to colorless, cubic crystal with hydrogen sulfide smell; industrial products are generally solution, orange or yellow.
Melting point (°C): 350
Relative density (water = 1): 1.79
Flash point (°C): 90
Solubility: Soluble in water, soluble in alcohol, ether, etc.
Solubility: 620g / L (20 ° C)
It is rapidly decomposed into sodium hydroxide and sodium sulfide in humid air, and it is exothermic and easy to spontaneously ignite.
It is heated to yellow and orange in dry air, black when molten, and soluble in HCl to produce H2S. The reaction is intense. It is easy to deliquesce, has strong hygroscopicity, is easy to oxidize, and often releases hydrogen sulfide and sulfur during storage.
Related reaction equations:
Calculate chemical data:
1. Hydrophobic parameter calculation reference value (XlogP):
2. Number of hydrogen bond donors: 0
3. Number of hydrogen bond acceptors: 1
4, the number of rotatable chemical bonds: 0
5. Number of tautomers:
6, topological molecular polar surface area (TPSA): 0
7, the number of heavy atoms: 2
8, surface charge: 0
9, complexity: 2
10. Number of isotope atoms: 0
11, determine the number of atomic stereocenters: 0
12. Uncertainty of the number of atomic stereocenters: 0
13. Determine the number of chemical bond stereocenters: 0
14, the number of uncertain chemical bond stereocenters: 0
15, the number of covalent key units: 2
1. Absorption method:
The hydrogen sulfide gas is absorbed by a sulfurized alkali solution (or a caustic soda solution). Since the hydrogen sulfide gas is toxic, the absorption reaction should be carried out under a negative pressure. In order to prevent the sulfur gas from being too polluted in the exhaust gas, several absorbers are operated in series, and the hydrogen sulfide content is reduced to a low level after repeated absorption. The absorption liquid is concentrated to obtain sodium hydrosulfide. Its chemical equation:
2. Sodium alkoxide is reacted with dry hydrogen sulfide to produce sodium hydrosulfide:
In a 150 mL tube with a branch tube, 20 mL of freshly distilled absolute ethanol and 2 g of a small piece of metal sodium with a smooth surface and no oxide layer were placed. A reflux condenser and a drying tube were placed on the flask, and the branch tube was first closed. When the sodium alkoxide was precipitated, about 40 ml of absolute ethanol was added in portions until the sodium alkoxide was completely dissolved.
A glass tube is inserted into the bottom of the solution through a branch pipe, and a dry hydrogen sulfide gas is introduced (note that the sealed branch pipe must not have air entering the flask). Allow the solution to reach saturation. The solution was suction filtered to remove the precipitate. The filtrate was stored in a dry Erlenmeyer flask, 50 mL of absolute diethyl ether was added, and a large amount of NaHS white precipitate was immediately deposited, and allowed to stand for a while, and then diethyl ether was added in several portions until the white layer precipitate no longer appeared in the upper layer solution. A total of about 110 mL of diethyl ether is required. The precipitate was quickly filtered off, washed with absolute diethyl ether for 2 to 3 times, dried and placed in a vacuum desiccator. The purity of the product can be analytically pure. For higher purity NaHS, it can be dissolved in ethanol and added to diethyl ether to recrystallize.
3, usually by the method of absorbing hydrogen sulfide by sodium hydroxide solution, when the content (sodium hydrosulfide mass fraction) is 70%, it is a dihydrate, which is in the form of flakes; if the content is lower, it is liquid, then Trihydrate.
4. Anhydrous sodium hydrosulfide:
A 1 liter three-necked round bottom flask was equipped with a stirrer and a reflux condenser, the latter of which was connected to a calcium chloride drying tube, and the other neck of the bottle was stoppered.
The flask was first rinsed with dry nitrogen. 200 ml (3.4 mol) of absolute ethanol was added, and then 12 g (0.522 mol) of cleaned sodium metal cut into small pieces was quickly added, stirred and refluxed. After the sodium was dissolved, the airway was placed at the end of the flask using a neck opening and a lower end. Hydrogen sulfide dried through phosphorus pentoxide was introduced into the stirred solution at a flow rate of 5 to 10 bubbles per second for 2 hours. Upon cooling, sodium hydrosulfide precipitated. When the solution was cooled to room temperature, 750 ml of anhydrous diethyl ether was added to completely precipitate sodium hydrogen sulfide.
Complete the following operations as quickly as possible to prevent the sodium hydride from absorbing water. The reaction solution was suction filtered with a sep. The ether was evaporated and the product was quickly dried in a vacuum dryer containing calcium chloride for several hours to obtain 29.4 g of a product having a purity of 98% or more.
5, sodium hydrosulfide aqueous solution:
The sodium sulfide nonahydrate was dissolved in freshly steamed steamed water and then diluted into a 13% Na2S (W/V) solution. 14 g of sodium hydrogencarbonate was added to the above solution (100 ml) under stirring at less than 20 ° C, and dissolved immediately and exothermed. Thereafter, 100 ml of methanol was added under stirring and below 20 °C. At this time, the heat was again released, and almost all of the crystalline sodium carbonate was precipitated immediately. After 0 minutes, the mixture was suction filtered, and the residue was washed with methanol (50 ml). The concentrations of the two are about 3.5 grams and 0.2 grams per 100 milliliters of solution, respectively.
The dye industry is used to synthesize organic intermediates and auxiliaries for the preparation of sulphur dyes. The tannery industry is used for depilation and tanning of hides and skins, as well as for wastewater treatment. The fertilizer industry is used to remove monomeric sulfur from activated carbon desulfurizers. It is a raw material for the manufacture of semi-finished products of ammonium sulfide and pesticide ethanethiol. The mining industry is heavily used for copper ore beneficiation. Used in the production of man-made fibers for sulfite dyeing.
Health hazard: It has a strong stimulating effect on the eyes, skin, mucous membranes and upper respiratory tract. After inhalation, it can cause paralysis of the throat and bronchi, inflammation and edema, chemical pneumonia or pulmonary edema. Symptoms of poisoning may include burning, wheezing, laryngitis, shortness of breath, headache, nausea, and vomiting. Direct contact with the eye can cause irreversible damage, even blindness.
Environmental hazard: It is harmful to the environment and can cause pollution to water bodies.
Explosion hazard: This product is a self-igniting item, highly toxic and highly irritating.
S25Avoid contact with eyes.
Avoid eye contact.
S36/37/39Wear suitable protective clothing, gloves and eye/face protection.
Wear appropriate protective clothing, gloves, and goggles or a mask.
S45In case of accident or if you feel unwell, seek medical advice immediately (show the label where possible.)
In the event of an accident or discomfort, seek medical attention immediately (show the label if possible).
R31Contact with acids liberates toxic gas.
In case of acid, it releases toxic gases.
R34 Causes burns.
Skin contact: Immediately remove contaminated clothing and rinse with plenty of running water for at least 15 minutes. Seek medical attention.
Eye contact: Immediately lift eyelids and rinse thoroughly with plenty of running water or saline for at least 15 minutes. Seek medical attention.
Inhalation: Remove quickly from the scene to fresh air. Keep the airway open. If breathing is difficult, give oxygen. If breathing stops, perform artificial respiration immediately. Seek medical attention.
Ingestion: Rinse mouth with water and drink milk or egg white. Seek medical attention.
Hazardous combustion products: hydrogen sulfide.
Fire-fighting methods: Firefighters must wear a filter-type gas mask (full face mask) or an isolated respirator, wear a full-body fire-fighting anti-virus suit, and extinguish the fire in the upwind direction. Move the container from the fire to the open space as much as possible. Spray water to keep the fire container cool until the end of the fire. If the container in the fire has changed color or produces sound from a safety relief device, it must be evacuated immediately.
Extinguishing media: water spray, foam, dry powder, carbon dioxide, sand.
Leakage emergency treatment
Emergency treatment: Quickly evacuate personnel from the contaminated area to a safe area, and conduct isolation to strictly restrict access. Cut off the fire source. It is recommended that emergency personnel wear self-contained positive pressure breathing apparatus and wear anti-virus suits. Cut off the source of the leak as much as possible. If it is liquid, it will prevent it from flowing into restrictive spaces such as sewers and flood drains.
Small amount of leakage: rinse with plenty of water, dilute the wash water and put it into the wastewater system.
A large number of leaks: building a dike or digging a pit. Transfer to a tank truck or special collector with a pump, recycle or transport to a waste disposal site for disposal. If it is solid, collect it in a dry, clean, covered container with a clean shovel. If there is a large amount of leakage, collect it for recycling or transport it to a waste disposal site for disposal.
Handling and storage
Operational precautions: closed operation, local exhaust. Operators must be specially trained to strictly follow the operating procedures. Operators are advised to wear a dust mask (full face mask), a tape anti-drug, and rubber gloves. Keep away from fire, heat, and smoking in the workplace. Use explosion-proof ventilation systems and equipment. Prevent smoke or dust from leaking into the workplace air. Avoid contact with oxidants and acids. Lightly load and unload during handling to prevent damage to the package. Equipped with the corresponding variety and quantity of fire-fighting equipment and leakage emergency treatment equipment. Empty containers may be harmful residues.
Storage Precautions: Store in a cool, ventilated warehouse. Keep away from fire and heat. It should be stored separately from oxidants, acids and food chemicals, and should not be mixed. Explosion-proof lighting and ventilation facilities are used. It is forbidden to use mechanical equipment and tools that are prone to sparks. The storage area should be equipped with leakage emergency treatment equipment and suitable containment materials. The “five pairs” management system for extremely toxic substances should be strictly implemented.