Cas No.16721-80-5 NaSH 70% Solid Flake
Colorless needle-like crystals. Deliquescence. At the melting
point, hydrogen sulfide is liberated. Easily soluble in water and
alcohol. The aqueous solution is strongly alkaline. It reacts with
acid to generate hydrogen sulfide. Bitter taste. Used in the dye
industry to synthesize organic intermediates and to prepare
auxiliaries for the preparation of sulfur dyes, in the leather
industry for dehairing and tanning of hides, in the chemical
fertilizer industry to remove monomer sulfur in activated carbon
desulfurizers, and in the mining industry for copper ore. It is
used for sulphurous acid dyeing in mineral processing and man-made
fiber production. It is the raw material for the manufacture of
semi-finished products of ammonium sulfide and pesticide ethyl
mercaptan. It is also used for wastewater treatment. It is obtained
by absorbing hydrogen sulfide gas from alkali sulfide or caustic
|Acidic Sodium Sulfide|
|sealed and dried|
Chinese name: Sodium HydrosulfideChinese synonyms: acidic sodium
sulfide; sodium hydrosulfide (70%); sodium hydrosulfide; sodium
hydrosulfide (NAHS, XH2O); sodium hydrogen sulfide; sodium hydrogen
sulfide anhydrous;English synonyms: hidrosulfurosodics;
file: 16721-80-5.mol;CAS NO: 16721-80-5;EINECS number: 240-778-0.
Appearance and properties: white to colorless cubic crystals with
the smell of hydrogen sulfide; industrial products are generally in
solution, orange or yellow.
Melting point (℃): 52.54
Relative density (water = 1): 1.79
Flash point (℃): 90
Solubility: soluble in water, soluble in ethanol, ether, etc.
It quickly decomposes into sodium hydroxide and sodium sulfide in
moist air, emits heat and is easy to ignite spontaneously.
It turns yellow or orange when heated in dry air, and turns black
when melted. It dissolves in HCl to produce H2S, and the reaction
is intense. Easily deliquescence, strong hygroscopicity, easy to
oxidize, hydrogen sulfide and sulfur are often released during
Relevant reaction equation:
1. Absorption method:
Use alkali sulfide solution (or caustic soda solution) to absorb
hydrogen sulfide gas. Because hydrogen sulfide gas is toxic, the
absorption reaction should be carried out under negative pressure.
In order to prevent excessive hydrogen sulfide in the exhaust gas
from polluting the air, several absorbers are operated in series
during production, and the hydrogen sulfide content is reduced to a
lower level after repeated absorption. The absorption liquid is
concentrated to obtain sodium hydrosulfide. Its chemical equation:
2. Sodium alkoxide reacts with dry hydrogen sulfide to produce
In a 150 mL flask with a branch tube, add 20 mL of freshly
distilled anhydrous ethanol and 2 g of sodium metal with a smooth
surface and no oxide layer. The flask is equipped with a reflux
condenser and a drying tube, and the branch tube is closed first.
When the sodium alkoxide precipitates, add about 40 ml of absolute
ethanol in batches until the sodium alkoxide is completely
Insert a glass tube straight into the bottom of the solution
through the branch pipe, and pass in dry hydrogen sulfide gas (note
that no air can enter the flask from the sealed branch pipe). Allow
the solution to reach saturation. The solution was suction filtered
to remove the precipitate. Store the filtrate in a dry Erlenmeyer
flask, add 50 mL absolute ether, and immediately a large amount of
NaHS white precipitate precipitates. Leave it for a period of time,
and then add ether several times until the upper layer solution no
longer appears white precipitate. A total of about 110 mL of ether
is needed. The precipitate was filtered out quickly, washed with
absolute ether for 2 to 3 times, sucked dry, and placed in a vacuum
desiccator. The purity of the product can reach analytical purity.
For higher purity NaHS, it can be dissolved in ethanol and
recrystallized with ether.
3. It is usually prepared by the method of absorbing hydrogen
sulfide with sodium hydroxide solution. When the content (mass
fraction of sodium hydrosulfide) is 70%, it is a dihydrate and is
in the form of flakes; if the content is lower, it is a liquid
4. Anhydrous sodium hydrosulfide:
A stirrer and a reflux condenser were installed on a 1-liter
three-necked round-bottom flask, the mouth of the latter was
connected to a calcium chloride drying tube, and the other neck of
the flask was plugged.
First flush the flask with dry nitrogen. Add 200 ml (3.4 mol) of
absolute ethanol, and then quickly add 12 g (0.522 mol) of clean
metal sodium cut into small pieces, stir and reflux. After
dissolving the sodium, use the neck of the flask to install a gas
tube with the lower end extending into the liquid. The hydrogen
sulfide dried by phosphorus pentoxide is passed into the stirred
solution at a flow rate of 5-10 bubbles per second for 2 hours.
After cooling, sodium hydrosulfide precipitates out. When the
solution was cooled to room temperature, 750 ml of anhydrous ether
was added to completely precipitate the sodium hydrosulfide.
Complete the following operations as quickly as possible to prevent
the flood of sodium hydride from absorbing water. The reaction
solution was filtered with a coarse-pore glass core funnel and
washed three times with anhydrous ether. The ether was evaporated,
and the product was quickly placed in a vacuum dryer containing
calcium chloride to dry for several hours, and 29.4 grams of
product with a purity of 98% or more was obtained.
5. Sodium hydrosulfide aqueous solution:
Dissolve sodium sulfide nonahydrate in freshly steamed filling
water, and then dilute it into a 13% Na2S (W/V) solution. Add 14 g
of sodium bicarbonate to the above solution (100 ml) under stirring
and below 20°C, which immediately dissolved and exothermed. Then,
100 ml of methanol was added while stirring and below 20°C. At this
time, heat was released again, and almost all crystalline sodium
carbonate was precipitated immediately. After 0 minutes, the
mixture was filtered with suction, and the residue was washed with
methanol (50 ml) several times. The filtrate contained not less
than 9 g of sodium hydrosulfide and not more than 0.6 of sodium
carbonate. The concentrations of the two are about 3.5 grams and
0.2 grams per 100 milliliters of solution, respectively.