Acetone, also known as dimethyl ketone, is the simplest ketone with a melting point of -95 degrees and a boiling point of 56 degrees. It is a colorless liquid with a special smell and can dissolve cellulose acetate and cellulose nitrate. There is no special toxicity to the human body, but it can cause headache, bronchitis and other symptoms after inhalation. May also lose consciousness if inhaled in large quantities. In daily life, it is mainly used for degreasing, dehydration, fixing and so on. Minor component in blood and urine. Propionaldehyde is mainly used in the production of propanol, propionic acid and trimethylolethane, and is used in the manufacture of synthetic resins, rubber accelerators and antioxidants. Acetone is the main ingredient in polish remover water for nail polish removal.

There are two ways to identify propionaldehyde:

(1) Heating method: Propionaldehyde boiling point (°C): 48, acetaldehyde boiling point (°C): 20.8, so the heating method can be used, the first boiling is acetaldehyde, and the latter boiling is propionaldehyde.

(2) Reagent method: Propionaldehyde can be identified with Benedict reagent, formaldehyde does not react with Benedict reagent, while propionaldehyde can react with Benedict reagent to produce brick red precipitate, and propionaldehyde cannot produce iodoform reaction.

There are also two identification methods for acetone:

(1) Acetone belongs to methyl ketones. One side of the ketone carbonyl is connected with a methyl group. The general formula is R-CO-CH₃. It can react with an alkaline solution of iodine to form acetic acid and iodoform precipitation.

(2) Take an appropriate amount of four reagents, add silver ammonia solution, propionaldehyde occurs in the silver mirror reaction, and then take an appropriate amount of the remaining three reagents, add NaHSO₃, and the precipitate generated is acetone.