p-Hydroxybenzoic acid

Application Areas

Relying on "bifunctional group reactivity + broad-spectrum bacteriostatic properties," it is primarily used in preservatives and fine chemical intermediates:

Preservative Field (largest use, accounting for over 60%):

Food Preservatives: Used in beverages, pastries, and condiments to inhibit mold and yeast growth. Addition amount ≤ 0.15 g/kg (GB 2760 standard). Advantages include high-temperature resistance (still effective after sterilization at 121℃) and no odor (does not affect food flavor).

Cosmetic Preservatives: Esterified with alcohols to generate parabens (p-hydroxybenzoates), used in face creams and shampoos. Broad-spectrum antibacterial (effective against both Gram-positive and Gram-negative bacteria), with stability superior to phenoxyethanol (effective within pH 4-8 range).

Pharmaceutical Preservatives: Added to eye drops, injections, and topical ointments to inhibit microbial contamination, complying with pharmacopoeia sterility requirements (bacteriostatic concentration ≤ 0.2%).

Fine Chemical Intermediates:

Synthesis of Ester Derivatives: Esterified with methanol, ethanol, propylene glycol, etc., to generate methylparaben, ethylparaben, and propylparaben, enhancing lipid solubility and expanding applications in oil-based products.

Pharmaceutical Raw Materials: Used to synthesize antibiotics (e.g., amoxicillin) and antipyretic analgesics (e.g., acetaminophen derivatives). Carboxyl and phenolic hydroxyl groups can precisely construct drug molecular structures.

Dyes and Pigments: Synthesize acid dyes and reactive dyes for dyeing wool and silk; bright colors with wash fastness ≥ grade 4; prepare fluorescent pigments for printing inks.

Polymer Material Modification: Copolymerized with epoxy resins to introduce phenolic hydroxyl groups, improving material adhesion and aging resistance, used in coatings and adhesives.

Other Fields:

Feed Additives: Inhibit mold reproduction in feed, extending storage period (addition amount ≤ 0.2 g/kg).

Electronic Chemicals: High-purity p-hydroxybenzoic acid (99.9% or above) is used to prepare photoresist sensitizers, improving lithography precision (resolution up to 30μm).

CAS NO: 99-96-7

EC NO: 202-804-9

Molecular Formula: C₇H₆O₃

Molecular Weight: 137.1133

Aliases: p-Phenolcarboxylic acid; p-Hydroxybenzoic acid; 4-Hydroxybenzoic acid;

Structural Formula: