Benzoic Acid

Benzoic Acid BP (Pharmaceutical)

C7H6O2 — 122.1 — 65-85-0

DEFINITION
Benzoic acid contains not less than 99.0 per cent and not more than the equivalent of 100.5 per cent of benzene carboxylic acid.

CHARACTERS
A white, crystalline powder or colourless crystals, odourless or with a very slight characteristic odour, slightly soluble in water, soluble in boiling water, freely soluble in alcohol and in fatty oils.

IDENTIFICATION
A. Melting point  121C to 124C.
B. Solution S (see Tests) gives reaction (a) of benzoates.

TESTS
Solution S
Dissolve 5.0 g in alcohol and dilute to 100 ml with the same solvent.
Appearance of solution
Solution S is clear and colourless.
Carbonizable substances
Dissolve 0.5 g with shaking in 5 ml of sulphuric acid. After 5 min, the solution is not more intensely coloured than reference solution.
Oxidizable substances
Dissolve 0.2 g in 10 ml of boiling water. Cool, shake and filter. To the filtrate add 1 ml of dilute sulphuric acid and 0.2 ml of 0.02 M potassium permanganate. After 5 min, the solution is still coloured pink.
Halogenated compounds and halides
All glassware used must be chloride-free and may be prepared by soaking overnight  in a 500 g/l solution of nitric acid, rinsed with water and stored full of water. It is recommended that glassware be reserved for this test.
Solution (a) Dissolve 6.7 g of the substance to be examined in a mixture of 40 ml of  1 M sodium hydroxide and 50 ml of alcohol and dilute to 100.0 ml with water. To 10.0 ml of this solution add 7.5 ml of dilute sodium hydroxide solution and 0.125 g of nickel-aluminium alloy and heat on a water-bath for 10 min. Allow to cool to room temperature, filter into a 25 ml volumetric flask and wash with three quantities, each of 2 ml, of alcohol. Dilute the filtrate and washings to 25.0 ml with water.  This solution is used to prepare solution A.
Solution (b) In the same manner, prepare a similar solution without the substance to be examined. This solution is used to prepare solution B.
In four 25 ml volumetric flasks, place separately 10 ml of solution (a), 10 ml of solution (b), 10 ml of chloride standard solution (8 ppm Cl) (used to prepare solution C) and 10 ml of water. To each flask add 5 ml of ferric ammonium sulphate solution, mix and add drop wise and with swirling 2 ml of nitric acid and 5 ml of mercuric thiocyanate solution. Shake. Dilute the contents of each flask  to 25.0 ml with water and allow the solutions to stand in a water-bath at 20 °C for 15 min. Measure at 460 nm the absorbance of solution A using solution B as the compensation liquid, and the absorbance of solution C using the solution  obtained with 10 ml of water as the compensation liquid. The absorbance of solution A is not greater than that of solution C (300 ppm).
Heavy metals
12 ml of solution S complies with limit test B for heavy metals (10 ppm).
Sulphated ash
Not more than 0.1 per cent, determined on 1.0 g.

Benzoic Acid USP

Benzoic Acid
C7H6O2 122.12
Benzoic acid.
Benzoic acid [65-85-0].
Benzoic Acid contains not less than 99.5 percent and not more than 100.5 percent of C7H6O2, calculated on the anhydrous basis.

Identification— Prepare a saturated solution of Benzoic Acid in water, and filter twice. To one portion of the filtrate add ferric chloride TS: a salmon-colored precipitate is formed. To a separate 10-mL portion of the filtrate add 1 mL of 7 N sulfuric acid and cool the mixture: a white precipitate forms in about 10 minutes; this precipitate is soluble in ether.
Congealing range: between 121 and 123.
Water: not more than 0.7%, a 1 in 2 solution of methanol in pyridine being used as the solvent.
Readily carbonizable substances— Dissolve 500 mg in 5 mL of sulfuric acid TS: the solution has no more color than Matching Fluid Q.
Residue on ignition: not more than 0.05%.
Heavy metals— Dissolve 2.0 g in 25 mL of acetone, and add 2 mL of water. Add 1.2 mL of thioacetamide-glycerin base TS and 2 mL of pH 3.5 Acetate Buffer, and allow to stand for 5 minutes: any color produced is not darker than that of a control made with 25 mL of acetone, 2.0 mL of Standard Lead Solution, and treated in the same manner. The limit is 10µg per g.
Readily oxidizable substances— Add 1.5 mL of sulfuric acid to 100 mL of water, heat to boiling, and add 0.1 N potassium permanganate, drop wise, until the pink color persists for 30 seconds. Dissolve 1.00 g of Benzoic Acid in the hot solution, and titrate with 0.1 N potassium permanganate VS to a pink color that persists for 15 seconds: not more than 0.50 mL of 0.10 N potassium permanganate is consumed.

Benzoic Acid FCC Food Grade

C7H6O2 Formula wt 122.12
INS: 210 CAS: [65-85-0]

DESCRIPTION
Benzoic Acid occurs as white crystals, scales, or needles. It begins to sublime at about 100° and is volatile with steam. One gram is soluble in 275 mL of water at 25°, in 20 mL of boiling water, in 3 mL of alcohol, in 5 mL of chloroform, and in 3 mL of ether. It is soluble in fixed and in volatile oils and is sparingly soluble in hexane.

REQUIREMENTS
Identification: Dissolve 1 g of sample in a 20:1 (v/v) mixture of water and 1 N sodium hydroxide, filter the solution, and add about 1 mL of ferric chloride TS. A buff-colored precipitate forms.
Assay: Not less than 99.5% and not more than 100.5% of C7H6O2, calculated on the anhydrous basis.
Lead: Not more than 2.0 mg/kg.
Readily Carbonizable Substances: Passes test.
Readily Oxidizable Substances: Passes test.
Residue on Ignition: Not more than 0.05%.
Solidification Point: Between 121-123C.
Water: Not more than 0.7%.

ACS Specifications
American Chemical Society

Benzoic Acid ACS Analytical Reagent

C6H5COOH
Formula Wt 122.12
CAS Number 65-85-0

REQUIREMENTS
Assay: 99.5% C6H5COOH
Freezing point: 122-123C

MAXIMUM ALLOWABLE
Residue after ignition: 0.005%
Insoluble in methanol: 0.005%
Chlorine compounds (as Cl): 0.005%
Sulfur compounds (as S): 0.002%
Heavy metals (as Pb): 5 ppm
Substances reducing permanganate: Passes test