Phenacetin[2]

Updated: 2026-11-01

Overview

Sodium benzoate (C7H5NaO2) is the sodium salt of benzoic acid, first synthesized in the late 19th century. As one of the most extensively studied preservatives, it gained FDA approval in the early 20th century and remains crucial in food safety systems worldwide. This cost-effective antimicrobial agent works particularly well in acidic environments (pH <4.5), making it ideal for carbonated drinks, fruit juices, and salad dressings. Its excellent water solubility differentiates it from benzoic acid, allowing broader formulation applications.

Physical and Chemical Properties

In its pure form, sodium benzoate appears as odorless white crystals or granules with a sweetish astringent taste. The compound shows remarkable stability under standard conditions but decomposes when heated above 300°C, producing sodium carbonate and benzene. Its antimicrobial efficacy stems from the undissociated benzoic acid molecules that form in acidic conditions, which can penetrate microbial cell membranes. This mechanism makes it particularly effective against yeast, molds, and some bacteria (minimum inhibitory concentration: 0.02-0.1%).

Main Applications

The food industry accounts for approximately 75% of sodium benzoate use, where it extends shelf life in products like soft drinks (0.03-0.05%), pickles (0.1%), and condiments. In pharmaceuticals, it preserves liquid medications (0.1-0.5%) including cough syrups and injectables. Industrial applications include corrosion inhibition in engine coolants and temporary preservation during textile processing. Emerging uses include silver preservation in photographic development and as a nucleating agent in plastic manufacturing.

Safety and Storage

Classified as GRAS by FDA when used within prescribed limits, sodium benzoate requires careful handling in industrial settings. Workers should use PPE (gloves, goggles) when handling powder to prevent eye/skin irritation and respiratory protection during bulk transfer. Store in original containers away from acids (to prevent benzene formation) and strong oxidizers. Typical shelf life is 3-5 years when stored below 25°C with <60% humidity. Always verify regulatory limits for target markets - the EU and US differ in permitted applications.

B2B Procurement Guide

For industrial buyers, prioritize suppliers with ISO 9001 certification and batch-specific Certificates of Analysis. Food/pharma-grade material should meet USP-NF, BP, or FCC standards. Key quality indicators include purity (>99.5%), heavy metal content (<10 ppm), and chloride levels. Consider logistics: bulk purchases (25kg bags or 1,000kg totes) typically offer 15-30% cost savings versus small packaging. For international shipments, confirm the supplier can provide REACH registration documents and proper HS classification (2916.31.00 for most countries).