【Difference】
The melting point of high-purity acetic acid is 16.7 degrees, so the acetic acid will form ice after the temperature is lower, and it is called glacial acetic acid. Acetic acid is the general name, can be high purity, can also be low purity. Glacial acetic acid and acetic acid are the same substance, with a strong pungent smell, the difference is only whether it is solid, acetic acid is generally liquid at room temperature of 20 ° C, and it is generally solid at low temperature of 16 ° C, which is also called glacial acetic acid.
Glacial acetic acid (pure matter), that is, anhydrous acetic acid, acetic acid is one of the important organic acids, organic compounds. It solidifies into ice at low temperatures and is commonly known as glacial acetic acid. The volume expansion during solidification may cause the container to rupture. The flash point is 39℃, the explosion limit is 4.0% ~ 16.0%, and the allowable concentration in the air does not exceed 25mg/m3. Pure acetic acid will freeze into ice-like crystals below the melting point, so anhydrous acetic acid is also called glacial acetic acid.
In addition, acetic acid is the earliest and most used acid flavor agent in China. Acetic acid (36%-38%), glacial acetic acid (98%), chemical formula CH3COOH, is an organic monic acid, the main component of vinegar.
【 Process 】
Acetic acid can be prepared by artificial synthesis and bacterial fermentation. Biosynthesis, the use of bacterial fermentation, accounts for only 10% of the world's total production, but is still the most important method of producing acetic acid, especially vinegar, because many countries' food safety regulations require that vinegar in food must be prepared by biological methods, and fermentation is divided into aerobic fermentation and anaerobic fermentation.
(1) Aerobic fermentation method
In the presence of sufficient oxygen, Acetobacter bacteria can produce acetic acid from foods containing alcohol. Usually cider or wine mixed with grains, malt, rice or potatoes is mashed and fermented. These substances can be fermented into acetic acid in the presence of a catalytic enzyme under oxygen.
(2) anaerobic fermentation method
Some anaerobic bacteria, including some members of the Clostridium genus, are able to convert sugars directly to acetic acid without the need for ethanol as an intermediate. Sucrose can be fermented into acetic acid in the absence of oxygen.
In addition, many bacteria are able to produce acetic acid from compounds containing only one carbon, such as methanol, carbon monoxide, or a mix of carbon dioxide and hydrogen.
【 Application 】
1. Acetic acid derivatives: mainly used in the synthesis of acetic anhydride, acetate, terephthalic acid, vinyl acetate/polyvinyl alcohol, cellulose acetate, ketenone, chloroacetic acid, halogenated acetic acid, etc
2. Medicine: Acetic acid, as a solvent and pharmaceutical raw material, is mainly used in the production of penicillin G potassium, penicillin G sodium, procaine penicillin, antipyretic tablets, sulfadiazine, sulfamethylisoxazole, norfloxacin, ciprofloxacin, acetylsalicylic acid, phenacetin, prednisone, caffeine and other intermediates: acetate, sodium diacetate, peracetic acid, etc
3. Pigment and textile printing and dyeing: mainly used in the production of disperse dyes and VAT dyes, as well as textile printing and dyeing processing
4. Synthetic ammonia: In the form of copper acetate ammonia liquid, used as a refined synthesis gas to remove a small amount of CO and CO2 contained in it
5. In photos: A recipe for a developer
6. In natural rubber: used as a coagulant
7. Construction industry: as an anticoagulant
In addition, it is also widely used in water treatment, synthetic fibers, pesticides, plastics, leather, coatings, metal processing and rubber industry.
Post time: Dec-18-2024