What Is Muriatic Acid?

Thiocyanic acid (English name sulfocyanic acid), also known as thiocyanic acid, is a colorless, volatile, strong odor acidic liquid. Crystals precipitate below 0 ° C, can dissolve in water, and exhibit strong acidity. Dilute solution is relatively stable. It can be decomposed into various cyanides by heating or reacting with thiohydrogen and inorganic acids, and react with olefins to form esters. The molecular formula is HSCN and the structural formula is H-S-CN. There is another isomer of thiocyanic acid, namely H-N = C = S. The free acid is a tautomeric mixture of the two, which cannot be separated yet, but its esters come in two forms. (Positive) thiocyanate RSCN is generally a liquid with onion odor. Isothiocyanate RN = C = S is often called mustard oil, which is a liquid with an unusually pungent odor. Thiocyanate is toxic and irritating to the eyes and skin. The molecular formula of a salt with a divalent metal is M (SCN) 2 (M represents a bivalent metal ion, such as Mg2 +, Ca2 +, Zn2 +, etc.). ^[1-2]

Chinese name: Thiocyanate
Foreign name: sulfocyanic acid

Chemical formula: HSCN
Also known as: Thiocyanic acid

Thiocyanate physical properties

[Appearance] is a colorless, volatile, strong acidic liquid.

Melting point -110

[Solubility] Soluble in water, ethanol and ether.

[Stability] Quickly decompose toxic gases such as nitrogen and sulfur at room temperature

Thiocyanate Properties

[CAS registration number] 463-56-9

[EINECS registration number]

[Molecular weight] 59.09

[Molecular formula and structural formula] The molecular formula is HSCN, and the structural formula is H-S-CN. There is another isomer of thiocyanic acid, namely H-N = C = S.

[Common chemical reactions] The dilute solution is stable. If heated or reacted with hydrosulfuric acid and inorganic acid, it will decompose into various cyanides.

[Incompatibility] acid, alkali

[Polymerization Hazard] Can polymerize

Main uses of thiocyanate

It can be used to prepare thiocyanate, ester, various thiocyanide and cyanide.

SCN ion is a good ligand. A particularly sensitive reaction of SCN ions is the formation of various red complexes with Fe. Therefore, potassium thiocyanate or ammonium thiocyanate is often used as a reagent for detecting Fe.

Method for producing thiocyanic acid

It can be prepared by the reaction of potassium hydrogen sulfate and potassium thiocyanate, or in a hydrogen stream under pressure or by passing hydrogen sulfide through warm lead thiocyanate. The reaction formula is as follows:

KSCN + KHSO ₄ HSCN + K ₂ SO ₄

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Thiocyanate toxicity and environmental impact

This product has a stimulating effect on mucous membranes. No specific effects of hydrogen cyanide. However, it should be noted that the impure preparation may contain HCN or a salt thereof. Moreover, it can decompose quickly to produce HCN at normal temperature. It must be prevented from poisoning by hydrogen cyanide and cyanide.

Thiocyanate packaging, transportation and storage

Thiocyanic acid is a strong acid, which is corrosive. It is packed in a plastic bucket or glass bottle that is resistant to corrosion. It is sealed to prevent leakage and stored in a warehouse where it is ventilated, protected from rain and sunlight. Keep away from fire and heat sources. It should be stored separately from acids and alkalis. Use explosion-proof lighting and ventilation facilities. Prohibit the use of spark-prone machinery and tools. The storage area should be equipped with spill emergency treatment equipment and suitable containment materials. Before transportation, check whether the packaging container is complete and sealed. During transportation, ensure that the container does not leak, collapse, fall, or damage.