Acid Hydrochloric Picric

Picric Acid is tested for the presence of resinous and tarry matters, sulphuric acid, hydrochloric acid, oxalic acid, and their salts. General impurities and adulterations, e.g., oxalic acid, nitrates, pii rntas, boric acid, alum, sugar, etc., remain insoluble on shaking the sample with ether, and may lx- further examined. The melting point of the pure acid, is 1 2° C. Dinitrophenol may be estimated by Allen s process (Journ. Soc. Dyers, etc., 4,84). Mineral or non-combustible matter must not exceed 0.3 per cent, by weight. 

Sulphuric Acid, Hydrochloric Acid, and Oxalic Acid-, and their salts are detected by adding to the filtered aqueous solution of the sample solutions of the picrates of barium, silver, and calcium. These salts are readily made by boiling picric acid with the carbonates of the respective metals and filtering other soluble salts of these methods may be substituted for the picrates, but they are less satisfactory. 

If the amine is soluble in water, mix it with a slight excess (about 25 per cent.) of a saturated solution of picric acid in water (the solubility in cold water is about 1 per cent.). If the amine is insoluble in water, dissolve it by the addition of 2-3 drops of dilute hydrochloric acid (1 1) for each 2-3 ml. of water, then add a sUght excess of the reagent. If a heavy precipitate does not form immediately after the addition of the picric acid solution, allow the mixture to stand for some time and then shake vigorously. Filter off the precipitated picrate and recrystaUise it from boiling water, alcohol or dilute alcohol, boiUng 10 per cent, acetic acid, chloroform or, best, benzene. 

The mixture is then chilled in an ice bath for at least 3 hours, and the olive-brown precipitate of the sparingly soluble copper complex of imidazole derivatives is filtered. The product is washed with about 500 ml. of cold water, suspended while moist (Note 4) in 11. of water, and rendered just acid to litmus by the addition of concentrated hydrochloric acid (about 40 ml.). Hydrogen sulfide is then passed into the suspension, with frequent shaking, until precipitation of the copper is complete (2-3 hours). The precipitate is filtered and extracted with 500 ml. of hot water in two or three portions. The clear, light brown to reddish brown filtrate and washings are boiled for 15 minutes, and then 60 g. (0.26 mole) of picric acid is added with stirring heating is continued until solution is complete. 

Sodium azide, Lead acetate, Water Picric acid. Sodium hydroxide. Lead nitrate Styphinic acid. Sodium hydroxide, Lead-II-nitrate Styphinic acid. Magnesium carbonate. Lead nitrate. Nitric acid Phloroglucinol, Glacial acetic acid. Sodium nitrite. Lead nitrate Acetylene, Arsenic trichloride. Mercuric chloride. Hydrochloric acid... 

Prolonged heating of Tetryl at 120° yields Picric Acid (see Vol 8, P2S5-R to P295-L). Tetryl is reduced and hydrolized to 2,4,6-tri-amino phenol by the action of tin and hydrochloric acid (Ref 3)... 

Dilute Aqueous Solutions. Acidify a dilute solution of picric acid (100 mL of 0.4%) to pH 2 by the addition of 2 mL of concentrated hydrochloric acid. Add granular tin (30 mesh, 1 g) and allow the mixture to stand at room temperature. The solution will darken gradually as the picric acid is reduced. After 14 days, no picric acid remains. This method can be used to dispose of 45-gallon drums of dilute solutions of picric acid. To determine when the picric acid is completely reacted, samples of the solution are analyzed by thin-layer chromatography on silica gel, eluting with methanol toluene glacial acetic acid,... 

Picric acid Mineral acids, i.e., hydrochloric, nitric, sulfuric... 

Hypochlorites decompose picric acid, which undergoes chlorination to form chloropicrin. The reaction is carried out with calcium hypochlorite. The calcium hydroxide formed in the reaction neutralizes the hydrochloric acid formed. This is a commercial method of preparation of chloropicrin. 

When reacted with chlorine, aqua regia or potassium chlorate in the presence of hydrochloric acid, picric acid yields chloranil along with chloropicrin ... 

Conductometric and spectrophotometric behavior of several electrolytes in binary mixtures of sulfolane with water, methanol, ethanol, and tert-butanol was studied. In water-sulfolane, ionic Walden products are discussed in terms of solvent structural effects and ion-solvent interactions. In these mixtures alkali chlorides and hydrochloric acid show ionic association despite the high value of dielectric constants. Association of LiCl, very high in sulfolane, decreases when methanol is added although the dielectric constant decreases. Picric acid in ethanol-sulfolane and tert-butanol-sulfolane behaves similarly. These findings were interpreted by assuming that ionic association is mainly affected by solute-solvent interactions rather than by electrostatics. Hydrochloric and picric acids in sulfolane form complex species HCl and Pi(HPi). ... 

The failure of the Fuoss equation to reproduce experimental data appears particularly evident by conductometric measurements of hydrochloric acid (18) and by spectrophotometric measurements of picric acid (21) which we have carried out in TMS at 35° and 30°C, respectively. 

The AT-oxides and AT-hydroxy compounds have acidic properties, but basic properties are not suppressed to a great extent since salts with picric and hydrochloric acids can still be formed. 

The reaction is carried out in alkaline solution (sodium or potassium hydroxide, or a mixture of the corresponding carbonates) so as to dissolve the nitro-compound and to neutralise the hydrochloric acid which otherwise impedes the chlorination of the picric acid. The reaction takes place very readily at a low temperature (between o and 5° C.). 

Tetrabenzylarsonium chloride, (CeHs.CH2)4AsCl.— This may be isolated by heating benzyl chloride and tribenzylarsine under reflux for a long time, or in quantitative yield by heating the two substances in a sealed tube at 170° to 175° C. for three hours. The temperature should be kept below 180° C., or dibenzylarsine trichloride is formed. Tetrabenzylarsonium chloride forms triclinic crystals, M.pt. 160° C., readily soluble in hot water or alcohol. It is slowly decomposed by concentrated hydrochloric acid at high temperatures and imder pressure. The aqueous solution gives precipitates with nitric acid, potassium dichromate, potassium thiocyanate, potassium bromide, potassium iodide, picric add, and platinic chloride. 

Manufacture (1) Chlorobenzene is nitrated with a mixture of sulphuric acid and nitric acid to produce dinitrochlorobenzene, which is synthesized to dinitro-sodium phenolate under reaction with sodium hydroxide. This is further changed to dinitrophenol with hydrochloric acid and then the dinitrophenol is nitrated by a mixture of sulphuric acid and nitric acid to trinitrophenol5 picric acid. (2) Phenol is mixed with cone, sulphuric acid and heated to obtain phenol-sulphonic acid. This is nitrated with a mixture of sulphuric acid and nitric acid to trinitrophenol. 

Cleaning Up The filtrate from this reaction and the product as well can be disposed of by dilution with a large volume of water and flushing down the drain. Larger quantities of moist picric acid (1 g) can be reduced with tin and hydrochloric acid to the corresponding triaminophenol. Dry picric acid is said to be hazardous and should not be handled. 

Mercuric oxide (8-4 grams) is shaken for several hours with a solution of 15 grams of picric acid in 800 c.c. of water at 80° C., when orange-yellow needles separate. If this mixture is then boiled the anhydride results. It yields small, pale yellow crystals which are only slightly soluble in the usual solvents and decompose without melting. In aqueous solution it is a non-electrolyte, and with dilute hydrochloric acid the ehloro-... 

Yeast is the chief source of ribosenucleic acid, one of the simplest methods of isolation being that of Levene. It consists in adding, with grinding, an aqueous solution of potassium hydroxide to a thick paste of pressed yeast, till faintly alkaline to litmus saturated aqueous picric acid solution is now added and the mixture filtered. The filtrate contains nucleic acid, which is precipitated by adding hydrochloric acid. 

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