Hydrochloric acid, effect

Hydrolysis of dimethyl 3-methyl-3//-3-benzazepine-2,4-dicarboxyiate (3) with 50% sulfuric acid, or with 20% hydrochloric acid, effects loss of the nitrogen function and formation of the indane-2-carboxylic acid 4.25... 

Optically pure vinylglycine derivatives 3 can be prepared by reacting lithiated (2aldol adducts 212. Hydrolysis of the adduct, followed by heating in 5N hydrochloric acid, effected ester hydrolysis and Peterson elimination to give the vinylglycine derivatives. 

A few compounds of cobalt and tin have been described. By fusing together at high temperatures an excess of stannic oxide and cobaltous oxide, using potassium chloride as a flux, Basic Cobalt Stannate, CoSnO,.CoO or Co2Sn04, is obtained.1 The potassium chloride is removed from the cooled mass with water, whilst warm dilute hydrochloric acid effects the solution of the stannate. The pure salt is dark green in colour density 6-30 at 18° C. 

In solution potassium ruthenate is of a deep orange colour, but in dilute solution assumes a green colour, due to formation of per-ruthenate. Hydrochloric acid effects the precipitation of an oxide, chlorine being simultaneously evolved. The solution stains the skin black owing to separation of oxide. 

A still further purification of the rhodium is effected 3 by fusing the metal obtained in the preceding manner to dull redness with metallic zinc, whereby the compound RhZn2 is formed, with considerable heat evolution, a portion of the zinc being volatilised. On cooling, treatment of the mass with concentrated hydrochloric acid effects the solution of the excess of zinc, the insoluble crystalline alloy remaining unaffected. 

Stereospeeific synthesis of IJ-dieues. Corey el al. have described a new synthesis of 1,3-dienes based on the highly stereospeeific cis addition of alkylcopper reagents to a,p-acctylenic carbonyl compounds (3, 108). Thus the reaction of methyl 4-trimethyl-siloxy-2-nonynoate (I ) in THF with divinylcopperlithium (1.25 cq.) at - 90° and then at — 78° affords the pure madduct (2) in > 90% yield. Treatment of (2) with melhanolic hydrochloric acid effects cleavage of the trimethylsilyl ether and lactonization to give (3). 

On the other hand, LTA oxidation in AcOH of ( )-discretine (378) gave an inseparable mixture of ( )-5a- and ( )-5j8-acetoxy-3-hydroxy-2,10,ll-trimethoxytetrahydroprotoberberines (379 and 380) in 30% yield (in a ratio of 5 11), 25% of the starting material 378 being recovered unchanged. Hydrolysis of the mixture with concentrated hydrochloric acid effected separation to give ( )-3,5a- and ( )-3,5)8-dihydroxy-2,10,l 1-trimethoxytetrahydroprotoberberines (381 and 382) in 20 and 48% yield. 

Treatment of the 5-amino-4-carboxamido-2-j8-D-ribofuranosylthiazole 792 with sodium nitrite and hydrochloric acid effected the formation of the... 

Hot (80 °C) O.IM hydrochloric acid effects rapid (20 min) regioselective hydrolysis of 4-cyano-imino-3-(methoxymethyl)perhydro-l,3,5-oxadiazine (30) (see Section 6.18.10.1.1) to 4-cyano-iminoperhydro-l,3,5-oxadiazine in 72% yield <83BCJ3319>. 

Amorphous carbon, having a far greater effective surface area than either diamond or graphite, is the most reactive form of carbon. It reacts with both hot concentrated sulphuric and hot concentrated nitric acids in the absence of additional oxidising agents but is not attacked by hydrochloric acid. 

Lead reacts only briefly with dilute hydrochloric and sulphuric acids for both lead(Il) chloride and lead(Il) sulphate are insoluble and form a film on the lead which effectively prevents further attack. Lead, however, does slowly dissolve in both concentrated sulphuric and hydrochloric acids. The sulphuric acid is reduced to sulphur dioxide ... 

Hydrolysis of Potassium Ethyl Sulphate. Dissolve about i g. of the crystals in about 4 ml. of cold distilled water, and divide the solution into two portions, a) To one portion, add barium chloride solution. If pure potassium ethyl sulphate were used, no precipitate should now form, as barium ethyl sulphate is soluble in water. Actually however, almost all samples of potassium ethyl sulphate contain traces of potassium hydrogen sulphate formed by slight hydrolysis of the ethyl compound during the evaporation of its solution, and barium chloride almost invariably gives a faint precipitate of barium sulphate. b) To the second portion, add 2-3 drops of concentrated hydrochloric acid, and boil the mixture gently for about one minute. Cool, add distilled water if necessary until the solution has its former volume, and then add barium chloride as before. A markedly heavier precipitate of barium sulphate separates. The hydrolysis of the potassium ethyl sulphate is hastened considerably by the presence of the free acid Caustic alkalis have a similar, but not quite so rapid an effect. 

If much sodium bromide is present in the crude acetylmethylurea, this will not dissolve in the concentrated hydrochloric acid it dissolves, however, when the solution is diluted and has no effect upon the subsequent treatment with sodium nitrite. 

Attention is directed to the fact that if only minute amounts of material are available or if the substance is expensive, considerable economy may be effected by treating, e.g., the aqueous solution or suspension with the necessary quantity of concentrated sodium hydroxide solution or concentrated hydrochloric acid. 

Treat 1 ml. of the mixture with dilute hydrochloric acid until strongly acid. Note any evolution of gas or the separation of a sohd. Add dilute sodium hydroxide solution and observe the effect. 

Mercapto-imida2oliuin inner salts have been reported to rearrange under the influence of hydrochloric acid, producing S-aminothiazolium chlorides (Scheme 25) (36). Their N-acylated derivatives are obtained by cyclization of N-thiobenzoyl alkylaminoacetonitriles, effected with acyl or sulfonyl halides (Scheme 26) (34, 35). 

The effect of pressure on the solubility of chlorine ia hydrochloric acid has been reported for pressures varying from about 100 to 6500 kPa (1—6.5 atm) (20). At pressures above 200 kPa, there is a linear dependence of pressure on the solubility in the acid concentration range of 0.1—5.0 N. 

Copper and Copper-Containing Alloys. Either sulfuric or hydrochloric acid may be used effectively to remove the oxide film on copper (qv) or copper-containing alloys. Mixtures of chromic and sulfuric acids not only remove oxides, but also brighten the metal surface. However, health and safety issues related to chromium(VT) make chromic acid less than desirable. 

Fusion with caustic soda at 500—800°C in an iron cmcible is an effective method for opening pyrochlores and columbites (20). The reaction mixture is flaked and leached with water to yield an insoluble niobate which can be converted to niobic acid in yields >90 wt% by washing with hydrochloric acid. 

---