1091. Benzoic Acid
Nomenclature
CAS number: 65-85-0
Benzenecarboxylic acid; phenylformic acid; dracylic acid. C7H6O2; mol wt 122.12.
C 68.85%, H 4.95%, O 26.20%.
Description and references
Occurs in nature in free and combined forms. Gum benzoin may contain as much as 20%. Most berries contain appreciable amounts (around 0.05%). Excreted mainly as hippuric acid by almost all vertebrates, except fowl. Mfg processes include the air oxidation of toluene, the hydrolysis of benzotrichloride, and the decarboxylation of phthalic anhydride: Faith, Keyes & Clark's Industrial Chemicals, F. A. Lowenheim, M. K. Moran, Eds. (Wiley-Interscience, New York, 4th ed., 1975) pp 138-144. Lab prepn from benzyl chloride: A. I. Vogel, Practical Organic Chemistry (Longmans, London, 3rd ed, 1959) p 755; from benzaldehyde: Gattermann-Wieland, Praxis des Organischen Chemikers (de Gruyter, Berlin, 40th ed, 1961) p 193. Prepn of ultra-pure benzoic acid for use as titrimetric and calorimetric standard: Schwab, Wicher, J. Res. Natl. Bur. Stand. 25, 747 (1940). Review: A. E. Williams in Kirk-Othmer Encyclopedia of Chemical Technology vol. 3 (Wiley-Interscience, New York, 3rd ed., 1978) pp 778-792.
Properties
Monoclinic tablets, plates, leaflets. d 1.321 (also reported as 1.266). mp 122.4°. Begins to sublime at ≈100°. bp760 249.2°; bp400 227°; bp200 205.8°; bp100 186.2°; bp60 172.8°; bp40 162.6°; bp20 146.7°; bp10 132.1°. Volatile with steam. Flash pt 121°C. pK (25°) 4.19. pH of satd soln at 25°: 2.8. Soly in water (g/l) at 0° = 1.7; at 10° = 2.1; at 20° = 2.9; at 25° = 3.4; at 30° = 4.2; at 40° = 6.0; at 50° = 9.5; at 60° = 12.0; at 70° = 17.7; at 80° = 27.5; at 90° = 45.5; at 95° = 68.0. Mixtures of excess benzoic acid and water form two liquid phases beginning at 89.7°. The two liquid phases unite at the critical soln temp of 117.2°. Composition of critical mixture: 32.34% benzoic acid, 67.66% water: see Ward, Cooper, J. Phys. Chem. 34, 1484 (1930). One gram dissolves in 2.3 ml cold alc, 1.5 ml boiling alc, 4.5 ml chloroform, 3 ml ether, 3 ml acetone, 30 ml carbon tetrachloride, 10 ml benzene, 30 ml carbon disulfide, 23 ml oil of turpentine; also sol in volatile and fixed oils, slightly in petr ether. The soly in water is increased by alkaline substances, such as borax or trisodium phosphate, see also Sodium Benzoate.Derivative
Barium salt dihydrate.Nomenclature
CAS number: 5908-68-9
Barium benzoate. C14H10BaO4.2H2O; mol wt 415.58.
C 40.46%, H 3.40%, Ba 33.04%, O 23.10%.
Properties
Nacreous leaflets. Poisonous. Soluble in about 20 parts water; slightly sol in alc.Derivative
Calcium salt trihydrate.Nomenclature
CAS number: 5743-30-6
Calcium benzoate. C14H10CaO4.3H2O; mol wt 336.35.
C 49.99%, H 4.79%, Ca 11.92%, O 33.30%.
Properties
Orthorhombic crystals or powder. d 1.44. Soluble in 25 parts water; very sol in boiling water.Derivative
Cerium salt trihydrate.Nomenclature
CAS number: 105546-51-8
Cerous benzoate. C21H15CeO6.3H2O; mol wt 557.50.
C 45.24%, H 3.80%, Ce 25.13%, O 25.83%.
Properties
White to reddish-white powder. Sol in hot water or hot alc.Derivative
Copper salt dihydrate.Nomenclature
CAS number: 6046-97-5
Cupric benzoate. C14H10CuO4.2H2O; mol wt 341.80.
C 49.20%, H 4.13%, Cu 18.59%, O 28.09%.
Properties
Light blue, cryst powder. Slightly soluble in cold water, more in hot water; sol in alc or in dil acids with separation of benzoic acid.Derivative
Lead salt monohydrate.Nomenclature
CAS number: 6080-57-5
Lead benzoate. C14H10O2Pb.H2O; mol wt 435.44.
C 38.62%, H 2.78%, O 11.02%, Pb 47.58%.
Properties
Cryst powder. Poisonous. Slightly sol in water.Derivative
Manganese salt tetrahydrate.Nomenclature
CAS number: 6146-97-0
Manganese benzoate. C14H10MnO4.4H2O; mol wt 369.23.
C 45.54%, H 4.91%, Mn 14.88%, O 34.67%.
Properties
Pale-red powder. Sol in water, alc. Also occurs with 3H2O.Derivative
Nickel salt trihydrate.Nomenclature
CAS number: 6018-91-3
Nickel benzoate. C14H10NiO4.3H2O; mol wt 354.97.
C 47.37%, H 4.54%, Ni 16.53%, O 31.55%.
Properties
Light-green odorless powder. Slightly sol in water; sol in ammonia; dec by acids.Derivative
Potassium salt trihydrate.Nomenclature
CAS number: 6100-02-3
Potassium benzoate. C7H5KO2.3H2O; mol wt 214.26.
C 39.24%, H 5.17%, K 18.25%, O 37.34%.
Properties
Crystalline powder. Sol in water, alc.Derivative
Silver salt.Nomenclature
CAS number: 532-31-0
Silver benzoate. C7H5AgO2; mol wt 228.98.
C 36.72%, H 2.20%, Ag 47.11%, O 13.97%.
Properties
Light-sensitive powder. Sol in 385 parts cold water, more sol in hot water; very slightly sol in alc.Derivative
Uranium salt.Nomenclature
CAS number: 532-60-5
Uranyl benzoate. C14H10O6U; mol wt 512.25.
C 32.83%, H 1.97%, O 18.74%, U 46.47%.