Melting point: >300 ░C
Boiling point: >300 ░C
Freezing point: -101 ░C
Water solubility: 560 g /l
Molecular weight: 144.1 g/mol
The substance is a white crystalline powder that gives a
colourless water solution. Flakes and granulates are other possible
forms. Water solutions are slightly basic (pH about 8). The substance
does no smell and has a harsh sour taste.
Sodium benzoate occurs naturally in many berries and fruits, such as
lingonberry and apple, in a concentration of about 0.05 %.
Sodium benzoate is produced by a reaction between benzoic acid and
sodium hydroxide or sodium carbonate. Solid sodium benzoate is
precipitated by cooling and evaporation of the reaction liquid. The
production in and import of sodium benzoate to EU is about 10 000 to 50
000 tonnes/year (2000).
The antimicrobial effect mainly affects yeast and bacteria and is most
effective at acid conditions (pH < 4). It is less effective on mould
fungus. Sodium benzoate does not kill micro-organisms. It just stops the
organism to grow.
An important use area for sodium benzoate is as a food preservative. It
is used in e.g. cold beverages (especially aerated), margarine, fish
products, roe products, marmalade, jam, pickle, salad dressing and
animal food. Sodium benzoate is also used as a preservative in various
technical water-based preparations such as cosmetics, paints, adhesives,
cleaning agents and metal treatment liquids. Other uses are as
anti-corrosion agent in antifreeze liquids (e.g. for cars), as additive
in plastic to improve strength and transparency and as stabilizer in
photo developers. Sodium benzoate is also used as raw material for
chemical synthesis, e.g. of benzyl benzoate.
Normally used concentrations are 0.05 to 0.1 % in fruit juice and 0.1 %
in skin creams. The regulatory limit in food and animal food in the US
is 0.1 %.
Sodium benzoate can in the presence of ascorbic acid form benzene.
One advantage of sodium benzoate compared with other preservatives is
its low production costs.