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Preparation method of salicylic acid

Views: 2     Author: Site Editor     Publish Time: 2022-04-13      Origin: Site

Preparation method of salicylic acid

1. Phenol reacts with sodium hydroxide to produce sodium phenol. After distillation and dehydration, carboxylation reaction is carried out with carbon dioxide to prepare sodium salicylate, which is acidified with sulfuric acid to obtain crude product. The crude product is refined by sublimation to obtain the finished product. Raw material consumption quota: phenol (98%) 704kg / T, caustic soda (95%) 417kg / T, sulfuric acid (95%) 500kg / T, carbon dioxide (99%) 467kg / T.

2. The preparation method is obtained by carboxylation of sodium phenol with carbon dioxide and acidification. Sodium phenol solution is prepared from phenol and liquid caustic soda, dried in vacuum, and then slowly fed with dry carbon dioxide at 100 ℃. When the pressure reaches 0.7 ~ 0.8MPa, stop feeding carbon dioxide and raise the temperature to 140 ~ 180 ℃. After the reaction, add clean water to dissolve sodium salicylate, decolorize and filter, and then add sulfuric acid to acidify, that is, separate out salicylic acid, and obtain the finished product after filtration, washing and drying.

Precautions for the use of salicylic acid

Hazard overview

Health hazard: the dust of this product is irritating to the respiratory tract, causing cough and chest discomfort after inhalation. It is irritating to the eyes,pure salicylic acid for sale - YuanfarChemicals and long-term contact can cause eye damage. Prolonged or repeated skin contact can cause dermatitis and even burns. Gastrointestinal tract irritation, tinnitus and renal damage occur after ingestion.

Environmental hazard: it is harmful to the environment and can cause pollution to water and atmosphere.

Explosion hazard: This product is flammable and irritating.

First aid measures

Skin contact: take off contaminated clothes immediately and rinse with plenty of flowing water for at least 15 minutes. See a doctor.

Eye contact: lift the eyelids immediately and rinse thoroughly with a large amount of flowing water or normal saline for at least 15 minutes. See a doctor.

Inhalation: leave the site to a place with fresh air. If breathing is difficult, give oxygen. See a doctor.

Ingestion: drink enough warm water to induce vomiting. Gastric lavage and catharsis. See a doctor.

Fire fighting measures

Hazard characteristics: flammable in case of open fire and high heat.

Harmful combustion products: carbon monoxide, carbon dioxide.

Fire extinguishing method: Firefighters must wear gas masks and full body fire fighting clothes to extinguish the fire in the upwind direction.

Fire extinguishing agents: fog water, foam, dry powder, carbon dioxide and sand.

Leakage emergency treatment

Emergency treatment: isolate the leakage contaminated area and restrict access. Cut off the fire source. It is recommended that emergency treatment personnel wear dust masks (full face masks) and gas suits. Avoid raising dust, sweep it carefully, put it in a bag and transfer it to a safe place. If there is a large amount of leakage, cover it with plastic cloth and canvas. Collect, recycle or transport to waste disposal site for disposal.

Handling and storage

Precautions for operation: closed operation, local exhaust. Operators must receive special training and strictly abide by the operating procedures. It is recommended that operators wear self-priming filter dust masks, chemical safety glasses, anti poison penetration work clothes and rubber gloves. Keep away from kindling and heat sources. Smoking is strictly prohibited in the workplace. Use explosion-proof ventilation system and equipment. Avoid dust generation. Avoid contact with oxidants and alkalis. Handle with care to prevent damage to packaging and containers. Fire fighting equipment and leakage emergency treatment equipment of corresponding varieties and quantities shall be provided. Empty containers may leave harmful substances.

Storage precautions: store in a cool and ventilated warehouse. Keep away from kindling and heat sources. Keep the container sealed. It shall be stored separately from oxidants and alkalis, and mixed storage shall not be allowed. Provide corresponding varieties and quantities of fire-fighting equipment. The storage area shall be equipped with appropriate materials to contain leakage.

YUANFAR CHEMICAL have been engaged in chemical business since 2001, and has our own factories  manufacturing hydrazine product

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