Salicylic acid is an organic acid with the chemical formula C7H6O3. It is a white crystalline powder, slightly soluble in cold water, readily soluble in hot water, ethanol, ether and acetone, and soluble in hot benzene. It is mainly used as an important raw material for fine chemicals such as pharmaceuticals, fragrances, dyes, pesticides and rubber additives. As a precursor to aspirin (acetylsalicylic acid) and a plant hormone, salicylic acid is naturally present in a variety of plants, especially in the bark of willow trees. It is mainly produced through the synthesis process of phenol and carbon dioxide. Modern production is achieved by reacting dry sodium phenolate (sodium phenolate salt) with carbon dioxide and then treating it with acid.