[Chemical Knowledge]：Production method and process of benzoic acid

Manufacturing Methods
of Benzoic Acid
Benzoic acid is an important organic chemical raw material, widely used in medicine, food, dyes, spices and other fields. This article will introduce the manufacturing method of benzoic acid, including chemical reaction principle, process flow, equipment selection, operation steps, quality control and safety production.

1. the principle of chemical reaction

The manufacture of benzoic acid is mainly realized by oxidation reaction. The commonly used oxidants are potassium permanganate, potassium dichromate, nitric acid and so on. Among them, the potassium permanganate oxidation method is the most commonly used, the reaction equation is:

C6H6 KMnO4 H2O → C6H5COOH MnO2 KOH

2. process

benzoic acid manufacturing process mainly includes the following steps: ingredients, oxidation, crystallization, centrifugal separation, drying, packaging.

1. Ingredients: Add a certain amount of benzyl alcohol to the ingredient tank, and add an appropriate amount of water at the same time, and stir evenly.
2. Oxidation: the prepared feed liquid is pumped into the oxidation reactor, and potassium permanganate is added for oxidation reaction, which generates benzoic acid and manganese dioxide.
3. Crystallization: The feed liquid in the oxidation reactor is pumped into a crystallizer, and the crystallization is cooled to obtain benzoic acid crystals.
4. Centrifugation: The crystals and mother liquor in the crystallizer were separated by a centrifuge to obtain benzoic acid crystals and mother liquor.
5. Drying: The benzoic acid crystals obtained by centrifugation are dried to obtain a dried benzoic acid product.
6. Packaging: The dried benzoic acid product is packaged to obtain the finished benzoic acid.

3. equipment selection

In the manufacturing process of benzoic acid, it is necessary to use the batching tank, oxidation reactor, crystallizer, centrifuge, drying equipment, etc. In the selection of equipment, should be based on the production scale, product quality requirements, process characteristics and other factors for comprehensive consideration, select the equipment to meet the production requirements.

4. Operation Steps

1. Add benzyl alcohol and water into the batching tank according to the proportion of ingredients, turn on the agitator and stir evenly.
2. Pump the prepared feed liquid into the oxidation reactor, and add potassium permanganate for oxidation reaction at the same time. Control the reaction temperature and time to ensure that the reaction is sufficient.
3. Pump the feed liquid in the oxidation reactor into a crystallizer, start the stirrer, and slowly cool down to precipitate benzoic acid crystals.
4. When the crystals in the crystallizer grow to a certain size, stop stirring, and pump the crystals and mother liquor together into a centrifuge for separation.
5. The separated benzoic acid crystals are dried, and the drying temperature and time are controlled to obtain a dried benzoic acid product.
6. Packaging the dried benzoic acid products and marking the product name, specification, production date and other information.

5. quality control

In order to ensure the quality of benzoic acid products is stable and reliable, it is necessary to carry out comprehensive quality control on the production process. This includes the quality control of raw materials, the quality control of the production process and the quality control of the finished product.

1. Quality control of raw materials: quality inspection of raw materials such as benzyl alcohol and potassium permanganate to ensure compliance with relevant standards.
2. Quality control of the production process: quality control of oxidation reaction, crystallization, centrifugal separation, drying and other processes to ensure standardized operation and stable product quality.
3. Quality control of finished products: quality inspection of finished benzoic acid, including purity, melting point, color and other indicators, to ensure compliance with relevant standards.

6. safety production

In the manufacturing process of benzoic acid, it is necessary to pay attention to safety production to ensure the safety of employees and equipment. Specifically include the following points:

1. Strictly implement the operating procedures to ensure that employees are familiar with the process and equipment operating specifications.
2. Equipped with complete safety facilities and protective equipment, such as fire prevention equipment, gas masks, etc.
3. Regularly carry out safety inspection and maintenance to ensure the normal operation of the equipment, and timely discover and eliminate potential safety hazards.

In short, the manufacture of benzoic acid requires knowledge of chemical reaction principles, process flow, equipment selection, etc., while paying attention to quality control and safety production requirements, in order to ensure product quality and production safety and stability.