Benzoic Acid

General Information (more on wikipidia)

Species Molecular Weight (g/mol) Density (g/L) Radius (m) Reference
Benzoic acid 122.12 1320 R [1]

Benzoic acid, C7H6O2 (or C6H5COOH), is a colorless crystalline solid and the simplest aromatic carboxylic acid. The name derived from gum benzoin, which was for a long time the only source for benzoic acid. This weak acid and its salts are used as a food preservative. Benzoic acid is an important precursor for the synthesis of many other organic substances.

Benzoic acid and its salts are used as a food preservative, represented by the E-numbers E210, E211, E212, and E213. Benzoic acid inhibits the growth of mold, yeast and some bacteria. It is either added directly or it is created from reactions with its sodium, potassium or calcium salt. The mechanism starts with the absorption of benzoic acid in to the cell. If the intracellular pH changes to 5 or lower the anaerobic fermentation of glucose through phosphofructokinase is decreased by 95%. The effectivity of benzoic acid and benzoate is thus dependent on the pH of the food.

Benzoic acid occurs naturally free and bound as benzoic acid esters in many plant and animal species. Appreciable amounts have been found most berries (around 0.05%). Ripe fruits of several Vaccinium species (e.g., cranberry, V. vitis idaea; bilberry, V. macrocarpon) contain as much as 300-1300 mg free benzoic acid per kg fruit. Benzoic acid is also formed in apples after infection with the fungus Nectria galligena. Among animals, benzoic acid has been identified primarily in omnivorous or phytophageous species, e.g., in viscera and muscles of the ptarmigan (Lagopus mutus) as well as in gland secretions of male muskoxen (Ovibos moschatus) or Asian bull elephants (Elephas maximus).

Diffusion of in water:

  • Alone at 25 degrees: $D = 1000 \ \mu m^{2} s^{-1}$ [1]

Diffusion of in PBS:

Diffusion of in cellular matrix:

Bibliography
1. Cussler, E. L. 1984. Diffusion - mass transfer in fluid systems. Cambridge University Press, Cambridge, United Kingdom.
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