Millon’s reaction

Mercuric nitrite reaction (Millon s reaction). Dissolve a very small crystal of tyrosine in i ml. of water, add 1-2 drops of mercuric nitrate solution, and I drop of dil. HjSO, and then boil. Cool, add i drop of sodium nitrite solution and warm again a red coloration is obtained. 

The protein molecule has free carboxyl and amino groups. Therefore it exhibits amphoteric properties. A number of color reactions have been developed for proteins to determine the presence of specific amino acids. The following are among the most important Millon s reaction. This reaction consists in the development of a red coloration when a substance containing a monohydroxyben-zene group is heated with a mixture of mercuric nitrate and nitrite (MUlon s reagent). Proteins giving this reaction contain tyrosine. 

Millon s Reaction. Add a few drops of Millon s reagent to solutions of gelatin, casein, egg albumen, glycine, resorcinol, and tyrosine. 

III. Millon s Reaction.—The reagent for this test is a solution of mercury in nitric acid containing nitrous acid. When the reagent is added to a solution or suspension of the protein in water, there is obtained either in the cold, or after boiling, a pink coloration of the fluid, or a pink to brownish red coloration of the precipitated protein. The reaction is given by all derivatives of benzene in which one of the hydrogen atoms has been replaced by a hydroxyl group. It thus serves as a delicate test for the presence of tyrosine in a protein. 

In addition to the precipitation reagents, a large variety of color-tests is in use for the detection of proteins. (A) In Millon s Reaction, the material is treated with nitric acid, in which a small... 

Yellow mercuric oxide may be obtained by precipitation from solutions of practically any water-soluble mercuric salt through the addition of alkah. The most economical are mercuric chloride or nitrate. Although yellow HgO has some medicinal value in ointments and other such preparations, the primary use is as a raw material for other mercury compounds, eg, Millon s ha.se[12529-66-7], Hg2NOH, which is formed by the reaction of aqueous ammonia and yellow mercuric oxide. 

TLC Color reactions with Millon s and Pauly s reagents ... 

The reaction is symbolized 2C102+H20=HC102+HC10S, so that the aq. soln. of N. A. E. Millon s chlorine trioxide will contain a mixture of chloric and chlorous acids and chlorine, and a soln. of the same gas in alkali lye will contain a mixture of the alkali hypochlorite, chlorite, chlorate, chloride. The chlorites are accordingly formed when soln. of chloric acid, HC103, or chlorine dioxide, C102, are partially reduced by the methods employed for the preparation of chlorine di- and tri-oxides. J. E. de Vrij 3 prepared the acid by reducing chloric acid with tartaric acid. G. Bruni and G. Levi used oxalic acid ... 

Reeves 8c Giddens stabilized cellulose nitrate with ammonia(Ref 31). Sampey(Ref 28) observed that the residue resulting from the reaction of ammonia with Hg exploded in a steel U tube connected with a glass Hg manometer when an attempt was made to clean the tube with a steel rod. Some of die gray-brown solid residue was recovered and detonated by heating in a crucible. Analysis indicated that the residue consisted of dehydration products of Millon s base[See CR 140. 853 (1905)1 and was readily sol in NaaSaO,. 5HjO... 

This coloration may, however, be due to maltol derived from torrefied malt. If, then, the reaction with ferric chloride is obtained, a portion of the aqueous solution of the residue from the ethereal extract should be tested with Millon s reagent2 a red coloration indicates salicylic acid, whilst no coloration shows that the reaction with ferric chloride is due to maltol. 

A number of preparative methods are available for the synthesis of WVI nitrides. The reaction of Millon s base [Hg2N]Br with WBr6 provides nitride 86 (Eq. (32)) [37]. The same reagent has been utilized in the synthesis of an interesting Wv complex 87 (Eq. (33)). This W2(p-N) complex can, in turn, be utilized to prepare a W nitride 88. Thus, treatment of 87 with Ph4PBr leads to a disproportionation reaction affording 88 and 89. 

Millon s reagent. Place 20 g of mercury in a beaker under a well-ventilated hood. Add 30 ml of concentrated nitric acid. When the reaction is complete, add 65 ml of water. It is best to make the solution in small amounts. 

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