Chemical Formula	C7H6O3
Molecular Weight	138.12
Structural Formula
Density	1,46 g/cm3
Melting Point	214-217℃
Boiling Point	336.2°C at 760 mmHg
Flash Point	171.3°C
Water Solubility	5 g/L (20℃)
Vapor Pressure	4.48E-05mmHg at 25°C
Solubility	Slightly soluble in water and chloroform; soluble in ethanol in any proportion; almost insoluble in carbon disulfide. Soluble in 125 parts of cold water.
Refractive Index	1.4600 (estimate)
Storage Conditions	2-8℃
Sensitivity	Sensitive to light
Appearance	White to beige crystalline powder
Physicochemical Properties	Properties White crystalline powder, odorless, tasteless, with a numbing sensation when tasted. Solubility Easily soluble in hot water, alcohols, and ethers; slightly soluble in cold water and benzene; insoluble in carbon disulfide. Soluble in 125 parts of cold water.

Main Uses: p-Hydroxybenzoic acid is a widely used organic synthesis raw material, especially its esters, including methyl p-hydroxybenzoate (methylparaben), ethyl p-hydroxybenzoate (ethylparaben), propyl ester, butyl ester, isopropyl ester, and isobutyl ester. It can be used as a food additive in soy sauce, vinegar, soft drinks (excluding soda), fruit flavorings, fruits and vegetables, pickled products, etc. It is also widely used as a preservative, antifungal agent, and bactericide in food, cosmetics, and pharmaceuticals.
p-Hydroxybenzoic acid is also used as an intermediate for dyes and pesticides. In pesticides, it is used to synthesize organophosphorus insecticides GYAP and CYP; in the dye industry, it is used to synthesize color developers for thermosensitive dyes; it can also be used for color films and the synthesis of oil-soluble color former "538" and as a raw material for plasticizers in Nylon 12. Additionally, it is used in liquid crystal polymers and plastics.