Aqueous hydrogen chloride

Moissanite, see Silicon carbide Molybdenite, see Molybdenum disulfide Molybdite, see Molybdenum(VI) oxide Molysite, see Iron(III) chloride Montroydite, see Mercury(II) oxide Morenosite, see Nickel sulfate 7-water Mosaic gold, see Tin disulfide Muriatic acid, see Hydrogen chloride, aqueous solutions... 

SYNONYMS Anhydrous hydrogen chloride, aqueous hydrogen chloride, spirits of salt. 

The phase system consists of a triethanolamine hydrogen chloride aqueous buffer solution pH 8.4 with 25% ethylene glycol as lower layer and benzene as upper layer. After 9000 transfers a mixture of hop alpha acids is obtained, in which prehumulone has been enriched by a factor of about ten. The final isolation is done by counter-current distribution with 360 transfers in the two-phase system iso-octane aqueous phosphate buffer pH 8.5 (K 1.0). Losses occur in view of the unstability of prehumulone. 

Phenylpropanolamine. - With catalyst prepared as previously described from 0.5g of palladium chloride and 3g of charcoal, it was possible to reduce two portions of 9.8g of isonitrosopropio-phenone (0.06 mol), dissolved in 150 cc. of absolute alcohol containing 7. Og of hydrogen chloride, to phenylpropanolamine in from 145 - 190 minutes with yields of the isolated chloride from 9.4g to 11. Og, or 84 to 98% of the theoretical. After recrystallization from absolute alcohol the salt melted at 191°. The free base was obtained by treating an aqueous solution of the hydrochloride with alkali on cooling, the liberated amino alcohol solidified and after recrystallization from water melted at 103°."... 

Chlorination may be performed either in carbon tetrachloride with SOCU (418) or by passing gaseous hydrogen chloride through an aqueous solution (419). 

Under neutral or slightly alkaline conditions, only the unstable hemiformal (CH O—CH2OH, methoxymethan0I) is produced. Alpha-chloromethyl ether is synthesized from aqueous formaldehyde, methanol, and hydrogen chloride (54). However, under anhydrous conditions, a carcinogenic by-product, bis(chloromethyl)ether is also formed (55). 

Hydrogen Chloride—Water System. Hydrogen chloride is highly soluble in water and this aqueous solution does not obey Henry s law at ah concentrations. Solubhity data are summarized in Table 5. The relationship between the pressure and vapor composition of unsaturated aqueous hydrochloric acid solutions is given in Reference 12. The vapor—Hquid equiHbria for the water—hydrogen chloride system at pressures up to 1632 kPa and at temperatures ranging from —10 to +70° C are documented in Reference 13. 

Hydrogen chloride is completely ionized in aqueous solutions at all but the highest concentrations. Thermodynamic functions have been deterrnined electrochemicaHy for equations 7 and 8. Values are given in Table 7. 

The specific heat of aqueous solutions of hydrogen chloride decreases with acid concentration (Fig. 4). The electrical conductivity of aqueous hydrogen chloride increases with temperature. Equivalent conductivity of these solutions ate summarized in Table 8. Other physicochemical data related to... 

Fig. 4. Specific heat of aqueous solutions of hydrogen chloride.

Sa.lts Salting out metal chlorides from aqueous solutions by the common ion effect upon addition of HCl is utilized in many practical apphcations. Typical data for ferrous chloride [13478-10-9] FeCl2, potassium chloride [7447-40-7] KCl, and NaCl are shown in Table 9. The properties of the FeCl2-HCL-H2 0 system are important to the steel-pickling industry (see Metal SURFACE TREATMENTS Steel). Other metal chlorides that are salted out by the addition of hydrogen chloride to aqueous solutions include those of magnesium, strontium, and barium. 

Tabic 9. Dependence of Solubility of Metal Chlorides on Hydrogen Chloride Concentration in Aqueous Solutions... 

Hydrogen chloride and the aqueous solution, muriatic acid, find appHcation in many industries. In general, anhydrous HCl is consumed for its chlorine value, whereas aqueous hydrochloric acid is often utilized as a nonoxidizing acid. The latter is used in metal cleaning operations, chemical manufacturing, petroleum well activation, and in the production of food and synthetic mbber. 

In the reaction of aEyl alcohol with an aqueous chlorine solution, addition of hypochlorous acid to the double bond of aEyl alcohol yields glycerol monochlorohydrin and as a by-product, glycerol dichlorohydrin. Thus, a poor yield of glycerol monochlorohydrin is obtained (8). To improve the yield of glycerol monochlorohydrin, addition of sodium carbonate in an amount equivalent to that of the hydrogen chloride in the aqueous chlorine solution, has been proposed (9). 

Chlorine in the presence of hydrogen chloride in an anhydrous organic solvent yields 2,4,6-trichloroariiline [634-93-5] (36,37). A mixture of aniline vapor and chlorine, diluted with an inert gas, over activated carbon at 400°C yields o-chloroaruline [95-51-2] (38). Aniline when treated with chlorine gas, in an aqueous mixture of sulfuric acid and acetic acid, at 105—115°C gives an 85—95% yield of -chlorarul [118-75-2] (39). 

The ratio of cycHc to linear oligomers, as well as the chain length of the linear sdoxanes, is controlled by the conditions of hydrolysis, such as the ratio of chlorosilane to water, temperature, contact time, and solvents (60,61). Commercially, hydrolysis of dim ethyl dichi oro sil a n e is performed by either batch or a continuous process (62). In the typical industrial operation, the dimethyl dichi orosilane is mixed with 22% a2eotropic aqueous hydrochloric acid in a continuous reactor. The mixture of hydrolysate and 32% concentrated acid is separated in a decanter. After separation, the anhydrous hydrogen chloride is converted to methyl chloride, which is then reused in the direct process. The hydrolysate is washed for removal of residual acid, neutralized, dried, and filtered (63). The typical yield of cycHc oligomers is between 35 and 50%. The mixture of cycHc oligomers consists mainly of tetramer and pentamer. Only a small amount of cycHc trimer is formed. 

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