Pyrophosphoric acid is an important chemical substance with a wide range of uses, mainly including the following aspects:
1. Chemical raw materials: Pyrophosphoric acid can be used as an important intermediate for the production of oxalic acid, phosphate, iron phosphate, sodium chlorate, ammonium phosphate, sodium phosphate and other chemical raw materials.
2. Metal surface treatment agent: pyrophosphoric acid is an excellent metal surface treatment agent, which can be used for anti-corrosion, polishing, cleaning and other treatment of metal surfaces.
3. Aluminum silicate catalyst: Pyrophosphoric acid is an important raw material for preparing aluminum silicate catalyst, which can be used in oil refining, pharmaceutical, chemical synthesis and other fields.
4. Food additive: Pyrophosphoric acid is a commonly used food additive, which can be used to produce meat products, dairy products, canned foods, etc., and has the functions of antisepsis, preservation, and acidizing.
5. Other fields: Pyrophosphoric acid can also be used to produce high-performance coatings, polyphosphates, etc. It is widely used in building materials, coatings, plastics, rubber, textiles, pharmaceuticals, pesticides and other fields.
In a word, pyrophosphoric acid is an important chemical raw material with a wide range of uses and application prospects. It will play a more important role in various fields in the future.
The synthesis methods of pyrophosphoric acid mainly include oxidation of phosphoric acid and phosphite, pyrolysis of ammonium phosphate, decomposition of tripolyphosphate and hydrolysis of pyrophosphate anhydride.
1. Oxidation of phosphoric acid and phosphite:
The oxidation of phosphoric acid and phosphite is one of the most commonly used pyrophosphoric acid production methods at present, and its steps are as follows:
Step 1: add pure phosphoric acid or phosphite into the reactor.
Step 2: inject oxygen or air into the reactor to make it react with phosphoric acid or phosphite to generate pyrophosphate.
Step 3: After the reaction, the product is separated, purified and dried to obtain pyrophosphate.
2. Pyrolysis of ammonium phosphate:
Pyrolysis of ammonium phosphate is another important production method of pyrophosphoric acid. Its steps are as follows:
Step 1: heat the mixture of ammonium phosphate and coke to high temperature to make it undergo pyrolysis reaction.
Step 2: Pyrophosphoric acid and by-products from the reaction are purified by cooling, separating, filtering, drying and other processing steps.
3. Decomposition method of tripolyphosphate:
The decomposition method of tripolyphosphate is another commonly used pyrophosphoric acid production method, and its steps are as follows:
Step 1: add tripolyphosphate into the reactor.
Step 2: add proper amount of water or acid to make it decompose.
Step 3: After the reaction, pure pyrophosphoric acid is obtained through filtration, evaporation, drying and other processing steps.
4. Hydrolysis of pyrophosphate anhydride:
The hydrolysis method of pyrophosphate anhydride is also a production method of pyrophosphate, and its steps are as follows:
Step 1: add pyrophosphate anhydride into the reactor.
Step 2: add proper amount of water or alkali to make it undergo hydrolysis reaction.
Step 3: After the reaction, purification is obtained through filtration, purification, drying and other processing steps.