Malonic acid is heated
Malonic acid, when heated, changes, and the product is special. Malonic acid is heated, decarboxylated, and acetic acid is formed. The opposite is true, the carboxyl group leaves, and the residual group forms a new structure.

When heated, the carbon in the carboxyl group is oxidized with hydrogen, and carbon dioxide escapes, and malonic acid then becomes acetic acid. The reaction formula can be expressed as: $HOOC - CH_2 - COOH\ stackrel {\ Delta} {\ longrightarrow} CH_3COOH + CO_2 ↑ $.

Or when malonic acid is heated, another way is to dehydrate within the molecule to form an acid anhydride. This change requires a specific temperature and catalytic agent. Although it is not the main way, it is also possible. The shape of its anhydride has a unique structure, which is also useful in organic transformation.

Looking at the change of malonic acid when heated shows that the organic reaction is complex, and the conditions are different. Scholars can explore the mystery of organic chemistry by examining its reason and observing its change.