Methyl red / alkyl red / methane red / acid red 2 / MR

English Name: methyl red; MR； C.I. 13020； Acid Red 2； 2-[4-(Dimethylamino)phenylazo]benzoic acid

Other name: Jiahong; Alkane red; Methane red; P-dimethylaminoazobenzene O-carboxylic acid; Acid red 2; 2 - [[4 - (dimethylamino) phenyl] azo] benzoic acid

CAS No.: 493-52-7

C15H15N3O2=269.30

Grade: ar

Grade: ind

PH discoloration range: 4.5 (red) ～ 6.2 (yellow)

Loss on drying: ≤ 1.0%

Ethanol dissolution test: acceptable

Mass absorption coefficient（ λ 1，pH 4.5）/[L/（cm•g）]：≥130.0

Mass absorption coefficient（ λ 2，pH 6.2）/[L/（cm•g）]：≥70.0

Burning residue: ≤ 0.2%

Maximum absorption wavelength（ λ 1，pH 4.5）/（nm）：523～528

Maximum absorption wavelength（ λ 2，pH 6.2）/（nm）：427～437

Physicochemical properties: shiny purple crystal or reddish brown powder. Soluble in ethanol and acetic acid, almost insoluble in water. After a long time storage, the sensitivity of ethanol solution can be significantly reduced due to the esterification of carboxyl groups

Purpose: biochemical research. In vivo staining of protozoa; Acid base indicator. Titration of ammonia, weak organic bases and alkaloids, but not applicable to organic acids other than oxalic acid and picric acid. It can be mixed with bromocresol green and methylene blue to shorten the color gamut and improve the sensitivity of color change. Adsorption indicator for precipitation titration, such as fluorine ion titration with thorium nitrate. Verification of free chlorine and chlorite

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