Methyl hydroxybenzoate potassium salt

Synonyms methyl 4-hydroxybenzoate potassium salt potassium methyl hydroxybenzoate. 

Hydroxybenzoic acid, methyl ester, potassium salt. See Potassium methylparaben 4-Hydroxybenzoic acid, methyl ester, sodium salt. See Sodium methylparaben 4-Hydroxybenzoic acid, 1-methylethyl ester. 

Boil about 01 g with 50 ml of N sodium hydroxide for thirty minutes under reflux. Cool, add 50 ml of 01N bromine and 10 ml of concentrated hydrochloric acid. Allow to stand for half an hour, shaking repeatedly during the first fifteen minutes, add 2 g of potassium iodide and titrate the liberated iodine with O IN sodium thiosulphate. 1 ml of 0 1 N bromine == 0 002536 g methyl hydroxybenzoate, CgHgOa 0 002902 g sodium salt of the methyl ester 0 003003 g propyl hydroxybenzoate, C10H12C3, and 0 003370 g sodium salt of the propyl ester. 

Phenol readily couples with diazonium salts to yield coloured compounds. The latter can be nsed for the photometric detection of phenol as in the case of diazotized 4-nitroaniline. Sahcylic acid (2-hydroxybenzoic acid) can be prodnced by the Kolbe-Schmitt reaction (stndied by the density functional method ) from sodinm phenolate and carbon dioxide, whereas potassium phenolate gives the para compound. Alkylation and acylation of phenol can be carried out with aluminium chloride as catalyst methyl groups can also be introduced by the Mannich reaction. Diaryl ethers can only be produced under extreme conditions. 

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