Hydrogen chloride gas is widely used in industrial production. Today, we will introduce you several industries commonly used in hydrogen chloride, which are also often used in our industry. In particular, the production of inorganic and organic drugs. Let's take a look:

1. Organic synthesis

At the temperature of 180 ° C ~ 200 ° C and with mercury salt (such as HgCl2) as a catalyst, hydrogen chloride and acetylene addition reaction occurs to produce vinyl chloride, and then under the action of the initiator, polymerization into PVC.

2. Bleaching and dyeing industry

Hydrochloric acid is used for pickling cotton cloth after bleaching and neutralizing alkali residue after mercerizing cotton cloth. In the printing and dyeing process, some dyes are insoluble in water and need to be treated with hydrochloric acid to make a soluble hydrochloride before they can be applied.

3. Metal processing

Before the plating of steel parts, wash with caustic soda solution to remove oil, and then soak with hydrochloric acid; Before metal welding, it is necessary to coat the welding joint with a little hydrochloric acid, etc., which uses the property that hydrochloric acid can dissolve metal oxides to remove rust. In this way, the metal surface can be firmly plated and welded. It can also be dissolved with some metals (such as aluminum) to achieve the purpose of removing the material by corrosion.

4. Food industry

When making chemical soy sauce, the steamed bean cake and other raw materials are soaked in a solution containing a certain amount of hydrochloric acid, maintain a certain temperature, hydrochloric acid has a catalytic effect, which can promote the hydrolysis of complex proteins, after a certain time, the formation of amino acids with umami, and then with caustic soda (or soda ash) neutralization, sodium amino acids. MSG is made in a similar way.

5. Production of inorganic and organic drugs

Hydrochloric acid is a strong acid that reacts with certain metals, metal oxides, metal hydroxides and most metal salts (such as carbonates, sulfites, etc.) to form hydrochloride. Therefore, hydrochloric acid is used in the production of many inorganic drugs. In medicine, many organic drugs, such as novocaine, thiamine hydrochloride (preparation of vitamin B1), are also made of hydrochloric acid.