(Ph. Eur. monograph 0066)<\/p>\n
C7<\/sub>H6<\/sub>O2<\/sub>\u00a0 \u00a0 122.1\u00a0 \u00a0 \u00a065-85-0<\/p>\n Action and use<\/strong><\/p>\n Antimicrobial preservative.<\/p>\n Preparations<\/strong><\/p>\n Compound Benzoic Acid Ointment<\/p>\n Benzoic Acid Solution<\/p>\n Benzenecarboxylic acid.<\/p>\n 99.0 per cent to 100.5 per cent.<\/p>\n White or almost white, crystalline powder or colourless crystals.<\/p>\n Slightly soluble in water, soluble in boiling water, freely soluble in ethanol (96 per cent) and in fatty oils.<\/p>\n A. Melting point (2.2.14): 121 \u00b0C to 124 \u00b0C.<\/p>\n B. Solution S (see Tests) gives reaction (a) of benzoates (2.3.1).<\/p>\n Dissolve 5.0 g in ethanol (96 per cent) R and dilute to 100 mL with the same solvent.<\/p>\n Solution S is clear (2.2.1) and colourless (2.2.2, Method II).<\/p>\n Dissolve 0.5 g with shaking in 5 mL of sulfuric acid R. After 5 min, the solution is not more intensely coloured than reference solution Y5<\/sub> (2.2.2, Method I).<\/p>\n Dissolve 0.2 g in 10 mL of boiling water R. Cool, shake and filter. To the filtrate add 1 mL of dilute sulfuric acid R and 0.2 mL of 0.02 M potassium permanganate. After 5 min, the solution is still coloured pink.<\/p>\n Maximum 300 ppm.<\/p>\n All glassware used must be chloride-free and may be prepared by soaking overnight in a 500 g\/L solution of nitric acid R, rinsed with water R and stored full of water R. It is recommended that glassware be reserved for this test.<\/p>\n Solution (a): Dissolve 6.7 g in a mixture of 40 mL of 1 M sodium hydroxide and 50 mL of ethanol (96 per cent) R and dilute to 100.0 mL with water R. To 10.0 mL of this solution add 7.5 mL of dilute sodium hydroxide solution R and 0.125 g of nickel-aluminium alloy R 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 3 quantities, each of 2 mL, of ethanol (96 per cent) R. Dilute the filtrate and washings to 25.0 mL with water R. This solution is used to prepare solution A.<\/p>\n Solution (b): In the same manner, prepare a similar solution without the substance to be examined. This solution is used to prepare solution B.<\/p>\n 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) R (used to prepare solution C) and 10 mL of water R. To each flask add 5 mL of ferric ammonium sulfate solution R5, mix and add dropwise and with swirling 2 mL of nitric acid R and 5 mL of mercuric thiocyanate solution R. Shake. Dilute the contents of each flask to 25.0 mL with water R and allow the solutions to stand in a water- bath at 20 \u00b0C for 15 min. Measure at 460 nm the absorbance (2.2.25) 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 R as the compensation liquid. The absorbance of solution A is not greater than that of solution C.<\/p>\n Maximum 0.1 per cent, determined on 1.0 g.<\/p>\n Dissolve 0.200 g in 20 mL of ethanol (96 per cent) R and titrate with 0.1 M sodium hydroxide, using 0.1 mL of phenol red solution R as indicator, until the colour changes from yellow to violet-red.<\/p>\n 1 mL of 0.1 M sodium hydroxide is equivalent to 12.21 mg of C7<\/sub>H6<\/sub>O2<\/sub>.<\/p>\n","protected":false},"excerpt":{"rendered":" (Ph. Eur. monograph 0066) C7H6O2\u00a0 \u00a0 122.1\u00a0 \u00a0 \u00a065-85-0 Action and use Antimicrobial preservative. Preparations Compound Benzoic Acid Ointment Benzoic Acid Solution DEFINITION Benzenecarboxylic acid. Content 99.0 per cent to 100.5 per cent. CHARACTERS Appearance White or almost white, crystalline powder or colourless crystals. Solubility Slightly soluble in water, soluble in boiling water, freely soluble…<\/p>\n","protected":false},"author":2,"featured_media":3560,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[174],"tags":[],"class_list":["post-3549","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-medicinal-substances"],"acf":[],"_links":{"self":[{"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/3549","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/comments?post=3549"}],"version-history":[{"count":2,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/3549\/revisions"}],"predecessor-version":[{"id":5229,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/posts\/3549\/revisions\/5229"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media\/3560"}],"wp:attachment":[{"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/media?parent=3549"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/categories?post=3549"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nhathuocngocanh.com\/bp\/wp-json\/wp\/v2\/tags?post=3549"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}DEFINITION<\/h2>\n
Content<\/h3>\n
CHARACTERS<\/h2>\n
Appearance<\/h3>\n
Solubility<\/h3>\n
IDENTIFICATION<\/h2>\n
TESTS<\/h2>\n
Solution S<\/h3>\n
Appearance of solution<\/h3>\n
Carbonisable substances<\/h3>\n
Oxidisable substances<\/h3>\n
Halogenated compounds and halides<\/h3>\n
Sulfated ash (2.4.14)<\/h4>\n
ASSAY<\/h2>\n