Colorless needle like crystals. Easy to deliquescence. At the melting point, hydrogen sulfide is released by decomposition. Easily soluble in water and alcohol. The aqueous solution exhibits strong alkalinity. React with acid to generate hydrogen sulfide. Bitter taste. Dye industry is used to synthesize organic intermediates and auxiliary agents for the preparation of Sulfur dye, leather industry is used for unhairing and tanning of raw hides, fertilizer industry is used to remove monomer sulfur in activated carbon desulfurizer, mining industry is largely used for copper ore dressing, artificial fiber production is used for Sulfurous acid dyeing, etc. It is the raw material for manufacturing Ammonium sulfide and semi-finished products of pesticide Ethanethiol, and also used for wastewater treatment. It is obtained by absorbing hydrogen sulfide gas from a solution of sulfide alkali or caustic soda.
brief introduction
Chinese name: Sodium hydrosulfide
Chinese synonym: acid Sodium sulfide; Sodium hydrosulfide (70%); Sodium sulfide hydrogen; Sodium sulfide (NAHS, XH2O); Sodium hydrogen sulfide; Anhydrous sodium hydrogen sulfide;
Synonyms in English: hidrosulfurosodics; Hydrogenosulfuredesodium (French); Hydrogenosulfuredesodium, anhydrate; Hydrogenosulfuredesodium, dihydrate; Hygrogensodiumsulfide; SODIUMHYLOGENSULFIDE (NAHS); Sodiumhydrosulfide (na (hs)); SODIUMHYROSULFIDE, ANHYDROUS;
Mol file: 16721-80-5.mol;
CAS NO: 16721-80-5;
EINECS number: 240-778-0.
physical property
Appearance and properties: White to colorless cubic crystals with a hydrogen sulfide odor; Industrial products are generally solutions, appearing orange or yellow.
Melting point (℃): 350
Relative density (water=1): 1.79
Flash point (℃): 90
Solubility: Soluble in water, soluble in ethanol, ether, etc.
Solubility: 620g/L (20 ℃)
chemical property
Stability: Stable
It quickly decomposes into sodium hydroxide and Sodium sulfide in humid air, and emits heat, which is easy to self ignite.
Heating in dry air turns yellow and orange, turns black when melted, and dissolves in HCl to produce H2S, resulting in intense reactions. Easy to deliquescence, strong hygroscopicity, easy to oxidize, and often releases hydrogen sulfide and sulfur during storage.
Regarding the reaction equation:
NaHS+HCl==H2S+NaCl
NaHS+H2O=heating=H2S+NaOH
Computational chemistry Data:
1. Reference value for hydrophobic parameter calculation (XlogP):
2. Number of hydrogen bond donors: 0
3. Number of hydrogen bond receptors: 1
4. Number of rotatable Chemical bond: 0
5. Number of Tautomer:
6. Topological molecule Polar surface area (TPSA): 0
7. Number of heavy atoms: 2
8. Surface charge: 0
9. Complexity: 2
10. Number of Isotope Atoms: 0
11. Determine the number of atomic structure centers: 0
12. Number of uncertain atomic construction centers: 0
13. Determine the number of Chemical bond stereo centers: 0
14. Number of uncertain Chemical bond stereocenters: 0
15. Number of Covalent bond units: 2
Preparation
1. Absorption method:
Absorb hydrogen sulfide gas with a sulfide alkali solution (or caustic soda solution). Due to the toxicity of hydrogen sulfide gas, the absorption reaction should be carried out under negative pressure. In order to prevent air pollution caused by excessive sulfurized hydrogen gas in the tail gas, several absorbers will be operated in series in production, and after multiple absorption, the hydrogen sulfide content will be reduced to a lower level. The absorption solution is concentrated to produce Sodium hydrosulfide. Its Chemical equation:
H2S+NaOH → NaHS+H2O
H2S+Na2S → 2NaHS
2. Sodium alkoxide reacts with dried hydrogen sulfide to produce Sodium hydrosulfide:
In a 150mL flask with a branch tube, add 20mL of newly distilled anhydrous ethanol and 2g of small pieces of metal sodium with smooth surface and no oxide layer, install a reflux condenser tube and a Drying tube on the flask, and close the branch tube first. When the sodium alcohol precipitates, add about 40 milliliters of anhydrous ethanol in batches until all the sodium alcohol is dissolved.
Insert a glass tube directly into the bottom of the solution through a branch pipe and introduce dry hydrogen sulfide gas (note that the sealed branch pipe should not allow air to enter the flask). Bring the solution to saturation. Filter the solution to remove sediment. Store the filtrate in a dry conical flask, add 50mL absolute ether, and a large amount of NaHS white precipitates will precipitate immediately. After a period of time, add ether several times until the white precipitates no longer appear in the upper solution. Approximately 110mL of ether is required in total. Quickly filter out the precipitate, wash it with absolute ether 2-3 times, suck it dry, and place it in a vacuum dryer. The purity of the product can reach analytical purity. If higher purity NaHS is needed, it can be dissolved in ethanol and recrystallized with ether.
3. Usually, it is prepared by absorbing hydrogen sulfide with sodium hydroxide solution. When the content (Sodium hydrosulfide mass fraction) is 70%, it is a dihydrate in the form of thin sheets; If the content is lower and in liquid form, it is trihydrate.
4. Anhydrous Sodium hydrosulfide:
Install an agitator and a reflux condenser on a 1L three neck Round-bottom flask. The nozzle of the latter is connected to a calcium chloride Drying tube, and the other neck of the flask is plugged.
First rinse the flask with dry nitrogen gas. Add 200 milliliters (3.4 moles) of anhydrous ethanol, then quickly add 12 grams (0.522 moles) of clean metal sodium cut into small pieces, stir and reflux. After dissolving the sodium, use the neck opening at the end of the flask to install a lower airway that extends into the liquid. Introduce the hydrogen sulfide dried by Phosphorus pentoxide into the stirred solution at the flow rate of 5-10 bubbles per second for 2 hours. After cooling, Sodium hydrosulfide precipitates out. When the solution is cooled to room temperature, add 750 ml of anhydrous ether to completely precipitate Sodium hydrosulfide.
Complete the following operations as soon as possible to prevent the mass flow of Sodium hydride from absorbing moisture. Suck and filter the reaction solution using a coarse porous glass core funnel, and wash it three times with anhydrous ether. Dry the ether and quickly place the product in a vacuum dryer containing calcium chloride for several hours to obtain 29.4 grams of product with a purity of over 98%.
5. Sodium hydrosulfide aqueous solution:
Dissolve Sodium sulfide hydrate in newly steamed stuffing water, and then dilute it to 13% Na2S (W/V) solution. Add 14 grams of sodium bicarbonate to the above solution (100 milliliters) with stirring and below 20 ℃, immediately dissolve and release heat. Afterwards, add 100 milliliters of methanol while stirring and below 20 ℃. At this point, the heat is released again, and almost all crystalline sodium carbonate precipitates immediately. After 0 minutes, the mixture is sucked and filtered, and the residue is washed with methanol (50 ml) in batches. The filtrate contains no less than 9 grams of sulfur Sodium hydride and no more than 0.6 grams of sodium carbonate. The concentrations of the two are approximately 3.5 grams and 0.2 grams per 100 milliliters of solution, respectively.
application
The dye industry is used as an auxiliary for the synthesis of organic intermediates and the preparation of Sulfur dye. The leather industry is used for unhairing and tanning of raw hides, as well as for wastewater treatment. The fertilizer industry is used to remove monomer sulfur from activated carbon desulfurizers. It is the raw material for manufacturing Ammonium sulfide and semi products of pesticide Ethanethiol. The mining industry is heavily used for copper ore beneficiation. In the production of man-made fiber, it is used in Sulfurous acid dyeing and other aspects.
matters needing attention
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Hazard Overview
Health hazard: It has a strong irritating effect on the eyes, skin, mucous membranes, and upper respiratory tract. Inhalation may cause spasm, inflammation and edema of larynx and bronchi, chemical pneumonia or Pulmonary edema. The symptoms of poisoning can include burning sensation, wheezing, laryngitis, shortness of breath, headache, nausea, and vomiting. Direct contact with the eyes 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 substance, highly toxic, and highly irritating.
Safety terminology
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 masks.
S45In case of accident or if you feel unwell, seek medical advice immediately (show the label when possible.)
If an accident occurs or you feel unwell, seek medical attention immediately (if possible, show your label).
Risk terminology
R31Contact with acids librates toxic gas
Releases toxic gases when exposed to acid.
R34 Causes burns
Causing burns.
First aid measures
Skin contact: Immediately remove contaminated clothing and rinse with plenty of flowing water for at least 15 minutes. Seek medical attention.
Eye contact: Immediately lift the eyelids and rinse thoroughly with a large amount of flowing water or physiological saline for at least 15 minutes. Seek medical attention.
Inhalation: Quickly remove from the scene to a place with fresh air. Maintain unobstructed respiratory tract. If breathing is difficult, administer oxygen. If breathing stops, immediately perform artificial respiration. Seek medical attention.
Ingestion: Rinse mouth with water and drink milk or egg white. Seek medical attention.
Fire protection measures
Harmful combustion product: hydrogen sulfide.
Extinguishing method: firefighters must wear filter type Gas mask (full face mask) or isolated respirator, wear full body fire and gas clothing, and extinguish the fire upwind. Move the container from the fire site to an open area as much as possible. Spray water to keep the fire container cool until the fire is extinguished. If the container in the fire has discolored or made a sound from the safety pressure relief device, it must be evacuated immediately.
Extinguishing agent: fog water, foam, dry powder, carbon dioxide, sand.
Leakage emergency response
Emergency response: Quickly evacuate personnel from the contaminated area to a safe area, isolate them, and strictly restrict entry and exit. Cut off the ignition source. It is recommended that emergency response personnel wear self-contained positive pressure respirators and protective clothing. Cut off the source of leakage as much as possible. If it is a liquid, prevent it from flowing into restricted spaces such as sewers and drainage ditches.
Small leakage: Rinse with a large amount of water, dilute the washing water and put it into the wastewater system.
Massive leakage: Build embankments or dig pits for containment. Transfer to a tank truck or dedicated collector with a pump for recycling or transportation to a waste disposal site for disposal. If solid, collect with a clean shovel in a dry, clean, and covered container. If there is a large amount of leakage, collect and recycle it or transport it to a waste disposal site for disposal.
Handling and Storage
Precautions for operation: Closed operation, local ventilation. Operators must undergo specialized training and strictly adhere to operating procedures. It is recommended that operators wear dust masks (full face masks), rubber protective clothing, and rubber gloves. Keep away from sparks and heat sources, and smoking is strictly prohibited in the workplace. Use explosion-proof ventilation systems and equipment. Prevent smoke or dust from leaking into the air of the workplace. Avoid contact with oxidants and acids. Light loading and unloading during transportation to prevent packaging damage. Equip corresponding types and quantities of firefighting equipment and emergency response equipment for leaks. Empty containers may have residual harmful substances.
Storage precautions: Store in a cool and ventilated warehouse. Keep away from sparks and heat sources. It should be stored separately from oxidants, acids, and edible chemicals, and should not be mixed for storage. Using explosion-proof lighting and ventilation facilities. Prohibit the use of mechanical equipment and tools that are prone to sparks. The storage area should be equipped with emergency response equipment for leaks and suitable storage materials. The "Five Double" management system for extremely toxic substances should be strictly implemented.
