Alkaline mixtures

If lighter colors than these are desired it is necessary to decolorize all the melanin in the hair in a preliminary step, and then add color back to the desired depth in a second treatment. This is known as a double-process treatment. The decolorization step consists of treating the hair with an alkaline mixture of persulfate salts and peroxide. The persulfate is added to the peroxide as a dry powder immediately before applying to the hair. Although the persulfate salts alone do not have any bleaching effect, the persulfate—peroxide mixture can remove all the melanin in the hair. Dark brown or darker hair can be lightened to a light blonde shade in about an hour. 

A solution containing 741 g (5.0 mols) of 1-phenyl-2-propylidenylhydrazine, 300 g (5.0 mols) of glacial acetic acid and 900 cc of absolute ethanol was subjected to hydrogenation at 1,875 psi of hydrogen in the presence of 10 gof platinum oxide catalyst and at a temperature of 30°C to 50°C (variation due to exothermic reaction). The catalyst was removed by filtration and the solvent and acetic acid were distilled. The residue was taken up In water and made strongly alkaline by the addition of solid potassium hydroxide. The alkaline mixture was extracted with ether and the ether extracts dried with potassium carbonate. The product was collected by fractional distillation, BP B5°C (0.30 mm) yield 512 g (68%). 

A mixture of jV-[(2-benzyl-3-methyl)phenyl]formamide (24. R1 = R3 = R4 = H R2 = Me 15 g, 68 mmol) in PPA (120 g) and POC1, (32 g. 208 mmol) was stirred at 120"C for 1.5 h. The mixture was cooled, diluted with cold H20. and basified by addition of aq KOH. The alkaline mixture was extracted with Et20, the extracts were dried (MgS04), and evaporated to give the crude product as an oily residue, which was purified by distillation under reduced pressure (bp 110 Q0.025 Torr). The distillate solidified on cooling to give the product as yellow needles yield 6g (43%) mp 68 C. 

The reversible reactions are initiated by an equilibrium between neutral and ionized forms of the monosaccharides (see Fig. 6). The oxyanion at the anomeric carbon weakens the ring C-O bond and allows mutarotation and isomerization via an acyclic enediol intermediate. This reaction is responsible for the sometimes reported occurrence of D-mannose in alkaline mixtures of sucrose and invert sugar, the three reducing sugars are in equilibrium via the enediol intermediate. The mechanism of isomerization, known as the Lobry de Bruyn-... 

Saponification of esters. Aqueom sodium hydroxide method. To hydrolyse an ester of an alcohol, reflux 5-6 g. with 50 ml. of 20 per cent, sodium hydroxide solution for 1-2 hours or until the ester layer disappears. Distil the alkaline mixture and collect about 6 ml. of distillate. This will ccmtain any volatile alcohol formed in the saponification. If the alcohol does not separate, i.e., is water-soluble, satmate the distillate with solid potassium carbonate an upper layer of alcohol is then usually formed. (The alcohol may be subsequently identified as the 3 5-dinitrobenzoate see Section III,27J.) Cool the residual alkaline mixture, and acidify it with dilute sulphuric acid. If no crystalline acid is precipitated, the acid may frequently be isolated by ether extraction, or it may be distilled from the acidified solution and isolated from (or investigated in) the distillate. (The acid may be subsequently identified, e.g., as the S-benzyl-iso-thiiu onium salt see Section 111,85,4.)... 

The condenser is again set downward, and the dropping funnel is replaced by a tube reaching nearly to the bottom of the flask. Steam is passed in, and the distillation is continued for several minutes after the boiling point reaches 100° (Note 5). The distillate is discarded. The mixture in the flask is cooled, and to it is added carefully 350 ml. of 12 N sodium hydroxide with stirring (Note 6). The alkaline mixture is then steam-distilled until the distillate is no longer basic (Note 7). 

Experiment 5. Angeli-Rimini Reaction.—A few drops of an aldehyde (any of those prepared) are dissolved in aldehyde-free 1 alcohol and about the same amount of benzene sulphohydroxamic acid (for the preparation of which see p. 192) is added in the case of aliphatic substances, twice as much of the acid is used. To this mixture, kept cool and shaken, 2 A-sodium hydroxide is added, in an amount judged to be about two molecular proportions. After standing for fifteen minutes the alkaline mixture is made just acid to Congo red and finally a drop of ferric chloride solution is added. An intense red colour is produced. 

One method he finally adopted was to mix the non-conducting, dry earth (lime, strontia, or baryta) with excess potash and fuse it. When he covered the alkaline mixture with naphtha and passed an electric current through it, he soon saw metallic globules rising and bursting into flame, but when the flame died out, there remained nothing except potash and the alkaline earth with which he had started (2,3). 

It is advisable to insert a thermometer only at intervals since the alkaline mixture attacks glassware to an appreciable extent on prolonged contact. 

The other prevalent method of oxidizing silicon uses wet chemical treatment, often in a sequence of steps called the RCA process [59]. In this process, silicon is both cleaned and oxidized by a process involving treatment with an alkaline mixture of ammonium hydroxide and hydrogen peroxide (called standard clean 1, or SCI), followed by treatment with an acidic HC1 and hydrogen peroxide mixture (SC2). The process leads to what is called a chemical oxide. This, like the thermal oxide, is Si02, but the wet oxidation process typically leads to a more hydroxylated Si02 surface. 

The crude -acetaminobenzene sulfonyl chloride (p. 3) obtained from 67.5 g. (0.5 mole) of acetanilide is shaken for two hours with a solution of 250 g. (1 mole) of crystallized sodium sulfite (Na2S03 7H2O) in 500 cc. of water. The reaction mixture is kept slightly alkaline by the addition at intervals of small portions of 50 per cent sodium hydroxide solution. The total volume of alkali used varies from 10 to 50 cc. After the alkaline mixture has been shaken for the two-hour period (Note 1) it is filtered, and the filtrate is acidified with 60 per cent sulfuric acid. If the acid is added slowly, the sulfinic acid comes down in fine crystals which after filtering and drying, melt at 1550 with decomposition (Note 2). The yield is 50-55 g. (43-47 per cent of the theoretical amount based on the acetanilide used). 

An old soda glass bottle of the hygroscopic nonahydrate had become severely etched and corroded internally by the contents, which had leaked through the perforated wall of the bottle. It is probable that the old material had become oxidised by air to a strongly alkaline mixture (below), corrosive to the soft glass. 

In a mildly alkaline mixture hemin forms hematin easily adding OH group. 

A 116 parts by weight of phenyl-p-methoxy-chloromethane (4-methoxybenzhydryl chloride) were added to 500 parts by weight of toluene and to the resulting mixture 65 parts by weight of 2-dimethylaminoethanol was added. Then the entire mixture was refluxed for two hours. The refluxed mixture was cooled and 250 parts by weight of a 10% solution of sodium hydroxide were added. This alkaline mixture was then steam distilled until the distillate was only weakly alkaline, for example a pH 7.5-8. 

The ionic complex [Rh(diphos)2]Cl can be reduced electrochemically in a variety of solvents to form the reactive species [Rh(diphos)2], The usual fate of this species is to abstract a hydrogen atom from the solvent and form [RhH(diphos)2]42 There is one instance where attack on the electrolyte, [Bu4N][C104], has been observed.43 Another school disputes this mechanism of [RhH(diphos)2] formation, and rightly questions the validity of deuterium labelling experiments which use alkaline mixtures of H20 and DjO.44... 

This gives as good results as when the o-bromotoluene is extracted from the alkaline mixture with ether. 

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