Brown solution

Like bromine, iodine is soluble in organic solvents, for example chloroform, which can be used to extract it from an aqueous solution. The iodine imparts a characteristic purple colour to the organic layer this is used as a test for iodine (p. 349). NB Brown solutions are formed when iodine dissolves in ether, alcohol, and acetone. In chloroform and benzene a purple solution is formed, whilst a violet solution is produced in carbon disulphide and some hydrocarbons. These colours arise due to charge transfer (p. 60) to and from the iodine and the solvent organic molecules. 

By warming either copper(I) oxide or a mixture of copper(II) chloride and copper with concentrated hydrochloric acid, until a deep brown solution is formed ... 

In both cases the copper(I) chloride dissolves in the acid to form the complex [Cu C ] + On pouring the brown solution into water. 

Anhydrous cupric sulphate is white but forms a blue hydrate and a blue aqueous solution. The solution turns yellow when treated with concentrated hydrochloric acid, dark blue with ammonia, and gives a white precipitate and brown solution when treated with potassium iodide. A yellow-brown aqueous solution of ferric chloride becomes paler on acidification with sulphuric or nitric... 

Iodine dissolves in liquid ethers giving brown solutions. 

Naphthylamine. Brown solution with a very slight pale blue fluorescence. 

Anhydrous liquid ammonia (note 2) (900 ml) was drawn from a cylinder and introduced into the flask. Iron(III) nitrate (lOO mg) was added and, as soon as a uniformly brown solution had formed (after stirring for a few seconds), about 0.7 g of lithium (from the starting amount of 7 g) was cut into two or three pieces and immediately introduced into the flask. After 10-15 min the blue colour had disappeared completely and a white suspension of lithium amide had formed. The remainder of the 7 g (1 mol) of lithium was then cut up and introduced. In most cases the conversion was finished v/ithin about 30 min (note 3). 

A mixture of 0.10 mol of freshly distilled 3-methyl-3-chloro-l-butyne (see Chapter VIII-3, Exp. 5) and 170 ml of dry diethyl ether was cooled to -100°C and 0.10 mol of butyllithium in about 70 ml of hexane was added at this temperature in 10 min. Five minutes later 0.10 mol of dimethyl disulfide was introduced within 1 min with cooling betv/een -100 and -90°C. The cooling bath vjas subsequently removed and the temperature was allowed to rise. Above -25°C the clear light--brown solution became turbid and later a white precipitate was formed. When the temperature had reached lO C, the reaction mixture was hydrolyzed by addition of 200 ml of water. The organic layer and one ethereal extract were dried over potassium carbonate and subsequently concentrated in a water-pump vacuum (bath... 

In the flask were placed 10.0 g of the propargylic amine (see Chapter lIII-5, Exp. 1). The air in the flask was replaced with nitrogen and a solution of 0.01 mol of KO-tert.-Ci,H,3 in 10 g of THF (free from hydroperoxide) was added. The mixture was warmed at about 40 C. A weakly exothermic reaction was observed and the temperature rose to about 45°C. After 1-2 min the gel originally present, had disappeared almost completely and a brown solution had formed. The refractive index of the solution (note 1) was measured after intervals of about 2 min. After the... 

To a solution of 0.05 mol of 4-phenyl-1,2-butadiene (see Chapter V, Exp. 19) was added in 10 min at -25 to -35°C a solution of 0.10 mol of ethyllithium in 80 ml of diethyl ether (see Chapter II, Exp. 1). After the addition the cooling bath was removed and the reaction mixture was warmed to 30 C in about 15 min and held at this temperature for an additional 15 min. The brown solution was then cautiously poured into 200 ml of ice-water. After separation of the layers four extractions with diethyl ether were carried out. The combined ethereal solutions... 

A suspension of 0.40 mol of sodium amide in 300 ml of liquid ammonia was prepared as described in Chapter II, Exp. 11. To the suspension was added with swirling a mixture of 0.25 mol of CHgCeC-S-Ph (see Chapter IV, Exp. 14) and 40 ml of THE in about 2 min (note 1). Swirling was continued after the addition. Three minutes later (note 1) the stopper with glass tube was placed on the flask. The brown solution was forced through the glass tube and the plastic tube, connected to it under 400 g of finely crushed ice, which was contained in a 3-1 conical flask (see Chapter I, Fig. 3, and accompanying description of this operation). The flask was placed for... 

A mixture of 0.25 mol of l,4-diethoxy-2-butyne (see Chapter VIII-6, Exp. 8) and 100 ml of dry diethyl ether was cooled at -45°C. A solution of 0.55 mol (note 1) of ethyllithium (note 2) (see Chapter II, Exp. 1) in about 450 ml of diethyl ether was added in 30 min. The temperature of the mixture was kept between -45 and -35°C. After the addition the mixture was stirred for an additional 20 min at -40°C. The light brown solution was then poured into 500 ml of ice-water, which had been saturated with nitrogen (note 3). After shaking the upper layer was separated off and the agueous layer was extracted twice with small portions of diethyl ether. 

In the flask were placed a solution of 7 g of anhydrous LiBr in 50 ml of dry THF, 0.40 mol of the allenic bromide (see Chapter VI, Exp. 31) and 0.50 mol of finely powdered copper(I) cyanide. The mixture was swirled by hand and the temperature rose in about 15 min to 60°C. It was kept between 55 and 60°C by occasional cooling in a water-bath. When the exothermic reaction had subsided, the flask was warmed for an additional 30 min at 55-60°C and the brown solution was then poured into a vigorously stirred solution of 30 g of NaCN and 100 g of NH,C1 in 300 ml of water, to which 150 ml of diethyl ether had been added. During this operation the temperature was kept below 20 c. The reaction flask was subsequently rinsed with the NaCN solution. After separation of the layers the aqueous layer was extracted with ether. The extracts were dried over magnesium sulfate and then concentrated... 

The reaction of H2O2 and H2SO4 generates a reddish brown solution whose absorbance is measured at a wavelength of 450 nm. A regression analysis on their data yielded the following uncoded equation for the response (Absorbance X 1000). 

The composition varies with the heat treatment and the end point according to x-ray diffraction studies it is a form of carbon that reconverts to weU-ordered graphite on heating to 1800°C. Before the use of x-rays, chemists used the Brodie reaction to differentiate between graphitic carbons and turbostratic carbons. Turbostratic carbons yield a brown solution of humic acids, whereas further oxidation of graphite oxide produces mellitic acid (benzenehexacarboxyhc acid) [517-60-2] ... 

B. Aminolhymol.—The crude, wet nitrosothymol so obtained is worked up with a mixture of 900 cc. of 28 per cent ammonia water (sp. g. 0.90) and 1600 cc. of water the brown solution is filtered free of a little resinous matter, and hydrogen sulfide is passed into it. The brown color disappears and a white precipitate of aminothymol forms. The passage of hydrogen sulfide is continued for thirty minutes longer (Note 3), when the base is filtered and washed well with cold water, contact with air being avoided as far as possible (Note 4). 

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