Manufacturing method of phosphite
Phosphite is an important raw material for the production of chemicals, which is widely used in pesticides, pharmaceuticals, plastics, dyes and other fields. In this article, we will introduce the manufacturing method of phosphite, including raw material preparation, reaction process, post-treatment and other aspects.
I. Raw material preparation
The main raw materials for manufacturing phosphite are phosphoric acid, sulfuric acid and methanol. Among them, the ratio of phosphoric acid and sulfuric acid is 1:1, and the amount of methanol is 30%~40% of the mass of phosphoric acid. In the process of raw material preparation, it is necessary to ensure the quality and purity of various raw materials to avoid adverse effects on the subsequent reaction.
II. Reaction process
1. Add phosphoric acid and sulfuric acid into the reactor according to the proportion and stir well.
2. While stirring, slowly add methanol and control the addition rate so that the reaction temperature does not exceed 80℃.
3. After the addition is completed, continue stirring for a certain period of time so that the reaction is fully carried out.
4. At the end of the reaction, the reaction solution was allowed to stand and layered to separate the phosphite and methanol sulfate layers.
III. Post-treatment
1. Distill the phosphite and collect the products in the specified fractions.
2. The distillation residue is treated to recover the methanol and sulfuric acid therein.
3. The collected phosphite is refined to remove impurities from it.
4. Precautions
1. During the manufacturing process, the reaction temperature and pH should be strictly controlled to ensure the smooth progress of the reaction.
2. Regular maintenance and servicing of the reaction equipment and piping are required to ensure normal operation of the equipment and quality of the product.
3. Environmental protection requirements should be followed when disposing of waste liquids and gases to avoid pollution of the environment.
In conclusion, the manufacturing method of phosphite acid involves a number of links, and the process parameters and operation points of each link need to be strictly controlled to ensure the quality and yield of the product. At the same time, it is also necessary to pay attention to environmental protection and safe production and other aspects to promote the sustainable development of the chemical production field.
