Double salt treatment

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. 

Uses. The principal use of monosodium phosphate is as a water-soluble soHd acid and pH buffer, primarily in acid-type cleaners. The double salt, NaH2P04 H PO, referred to as hemisodium orthophosphate or sodium hemiphosphate, is often generated in situ from monosodium phosphate and phosphoric acid in these types of formulations. Mixtures of mono- and disodium phosphates are used in textile processing, food manufacture, and other industries to control pH at 4—9. Monosodium phosphate is also used in boiler-water treatment, as a precipitant for polyvalent metal ions, and as an animal-feed supplement. 

The central carbon atom is derived from an aromatic aldehyde or a substance capable of generating an aldehyde during the course of the condensation. Malachite green is prepared by heating benzaldehyde under reflux with a slight excess of dimethyl aniline in aqueous acid (Fig. 2). The reaction mass is made alkaline and the excess dimethylaniline is removed by steam distillation. The resulting leuco base is oxidized with freshly prepared lead dioxide to the carbinol base, and the lead is removed by precipitation as the sulfate. Subsequent treatment of the carbinol base with acid produces the dye, which can be isolated as the chloride, the oxalate [2437-29-8] or the zinc chloride double salt [79118-82-4]. 

Aniline [62-53-3] M 93.1, f -6.0", b 68.3/lOmm, 184.4"/760mm, d 1.0220, n 1.585, n s 1.5832, pK 4.60. Aniline is hygroscopic. It can be dried with KOH or CaH2, and distd at reduced pressure. Treatment with stannous chloride removes sulfur-containing impurities, reducing the tendency to become coloured by aerial oxidn. Can be crystd from Et20 at low temps. More extensive purifications involve preparation of derivatives, such as the double salt of aniline hydrochloride and cuprous chloride or zinc chloride, or A -acetylaniline (m 114") which can be recrystd from water. 

The treatment of systems in which hydrates (or compounds), double salts, etc., are deposited, or of ternary systems, proceeds on the same lines as the investigation of the simpler cases considered in the preceding sections. 

Zinc hydroxy double salts are layered materials similar to layered double hydroxides which show intercrystalline reactivity and incorporate organic compounds between layers.337 Hydroxy double salts of high crystallinity can be obtained by reacting ZnO with organic metal salts in water. Zinc oxide crystals could then be prepared by thermal treatment of hydroxy zinc acetate.338... 

Modification of the trinitromethyl substituents of the derivative 31 was reported by a Russian team <2005KGS259> removal of one nitro group was achieved by treatment with potassium iodide at room temperature in good yield to give the double salt 9. 

Potassium sulfate also is produced from the mineral kieserite, MgS04 H2O by treatment with potassium chloride. The intermediate double salt obtained reacts further with potassium chloride to form potassium sulfate ... 

In one synthesis of this drug, L-proline (11-2) is acylated with the acid chloride (11-1) obtained from the addition of hydrogen chloride to the double bond in methacrylic acid followed by reaction with thionyl chloride to give amide (11-3) as a mixture of diastereomers. The pure 2S isomer is then isolated from the mixture by fractionation as the dicyclohexylamine salt. Treatment of that compound with ammonium hydrosulfide leads to the displacement of chlorine by a thiol group and the formation of captopril (11-4) [13]. 

Ammonium Tetranitrito - diammino - cobaltate, [Co(XH3)2 (N02)4]NH4, is prepared from cobaltous chloride by mixing an aqueous solution of the salt with aqueous ammonium-chloride solution, sodium nitrite, and ammonia, and oxidising the mixture by passing air through it for several hours. The solution is allowed to stand in air for some days, when crystals gradually separate. These are collected, washed, and reerystallised from water.3 The substance crystallises in brown rhombic prisms. It is decomposed on treatment with potassium hydroxide with evolution of ammonia, and a cold solution reacts with ammonia in presence of ammonium salts, with formation of flavo-dinitro double salts, of which [Co(NH3)4(N02)2][Co(NH3)2(N02)4] is typical. Oxalic acid transforms it into the oxalato-dinitrito-diammino-salt, [Co(NH3)2(N02)2(C204)]NH4. 

Aromatic organometallic compounds can be prepared by the treatment of diazonium salts (most often fluoroborates) with metals.386 Among the metals used have been Hg, Tl, Sn, Pb, Sb, and Bi. Another method consists of treating the double salt of the diazonium salt and a metal chloride with a metallic powder, e.g.,... 

Orthoformic ester has been prepared by the treatment of a mixture of chloroform and alcohol with sodium 1 by the action of dry sodium ethylate on chloroform 2 or on an ether solution of chloroform 3 by the action of alcoholic sodium hydroxide on chloroform 4 and by the action of alcoholic hydrochloric acid on ethyl formimido ester5 or its mercuric chloride double salt.6... 

Very recently it has been shown that treatment of the double salt of zinc chloride and p-hydroxybenzenediazonium chloride with ethyl alcohol leads to phenol (38% yield) and p, p -azophenol (ca. 60-66% yield).41... 

Methylene green, the nitro derivative of methylene blue, is an interesting dye. The nitration is effected in the same way as that of tropaeo-line, using the crude zinc chloride double salt without further treatment. 

The pink deposit which formed on the electrodes exploded on heating. It turned grn on treatment with w, gradually dissolved and settled out as an expl ppt. Ricca Pirrone (Ref 8) prepd an addn compd from 1 vol of 13% NiS04 and 3 vols of a 3% aq soln of a compd obtd by mixing equal vols of satd aq Hg(CN)i and NNaN,. The gtn compd, Hg(CNj)j Ni(Nj), did not explode when heated. X It blue solid, sol inw and exploding violently was described by Strecker Schwinn (Ref 11). This complex compd called Hexamminenickel Azide, [Ni (NH,),](N,) is listed in Table E under Ammines (See also Refs 7 9)- Double salts, such as Ni(Ns)i NH4Nj and Ni(Nj)2 KN, have been reported (Refs 1 4)... 

There remains one problem, that of applying the conditions of equilibrium just found to the phenomena ot equilibrium treated in the first section especially in the more complex cases last dealt with, that three or four substances take part in the equilibrium. Since the treatment for the case of three substances is contained in the lectures on the formation and dissociation of double salts, which have been published separately b we will here discuss only the case of chemical equilibrium between four substances, in connexion with the former example of two salts which sufier double decomposition. We may then generalize the results of the particular case in Lowenherz s... 

Basic salts are produced wdien cobalt salts are precipitated with sodium chromate, or when the alkali-containing double salts first produced by precipitation with ammonium or potassium chromates are subjected to continued treatment with hot water. The following double salts have been described ... 

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