Hydrohalic acids Hydrochloric acid

It is common practice to refer to the molecular species HX and also the pure (anhydrous) compounds as hydrogen halides, and to call their aqueous solutions hydrohalic acids. Both the anhydrous compounds and their aqueous solutions will be considered in this section. HCl and hydrochloric acid are major industrial chemicals and there is also a substantial production of HF and hydrofluoric acid. HBr and hydrobromic acid are made on a much smaller scale and there seems to be little industrial demand for HI and hydriodic acid. It will be convenient to discuss first the preparation and industrial uses of the compounds and then to consider their molecular and bulk physical properties. The chemical reactivity of the anhydrous compounds and their acidic aqueous solutions will then be reviewed, and the section concludes with a discussion of the anhydrous compounds as nonaqueous solvents. 

Halogenwasserstoff, m. hydrogen halide. -sSure, /. halogen hydracid, hydrohalic acid (general name for hydrochloric acid, hydro-bromic acid, etc.), -verbindung, /. hydrogen halide. 

Br, and I (but not F) for example, hydrochloric acid, HCl, and hydrobromic acid, HBr (HCl and HBr are hydrohalic acids acids that have hydrogen bonded to atoms of the halogen elements.)... 

Diaryl tellurium dichlorides are also obtained when air or oxygen is bubbled through a suspension of the diaryl telluriums in aqueous hydrochloric acid (Vol. IX, p. 1064) or when the diaryl tellurium compounds are electrochemically oxidized in hydrohalic acid solutions6. 

In addition to their action on the respiratory system and attacking the mucous membrane and skin, a major hazard of concentrated hydrohalic acids is direct contact with the skin, causing chemical bums. Some of these compounds, however, are important in biochemical processes. The hydrochloric... 

Diorgano tellurium oxides react with hydrohalic acids by regenerating the diorgano tellurium dihalides, the common starting materials for the preparation of diorgano tellurium oxides. The reactions with hydrochloric acid, hydrobromic acid , and hydroiodic acid, therefore, are not of synthetic importance. The reaction with hydrofluoric acid , however, is a convenient way of preparing diorgano tellurium difluorides. 

Other Halides of Niobium(v) and Tantalum(v). All six of these are yellow to brown or purple-red solids best prepared by direct reaction of the metals with excess of the halogen. The halides melt and boil at 200-300° and are soluble in various organic liquids such as ethers, CC14, etc. They are quickly hydrolyzed by water to the hydrous pentoxides and the hydrohalic acid. The chlorides give clear solutions in concentrated hydrochloric acid, forming oxo chloro complexes. 

In practical terms, hydrochloric acid is the most important of the hydrohalic acids, the aqueous solutions of the hydrogen halides. About 3 million tons of hydrochloric acid are produced annually for use in cleaning steel before galvanizing and in the manufacture of many other chemicals. 

Bromo and 3-chloroquinolines were prepared unexpectedly when the synthesis of quinolines via the addition of an alkyl Grignard to an o-trifluoroacetylaniline was quenched with hydrohalic acid (Scheme 53). The reaction requires a copper chloride catalyst. Interestingly, both cuprous and cupric chloride worked to form the 3-chloroquinolines when mixed with 1.5 equivalents of hydrochloric acid. Anilines with different groups were tolerated well under these reaction conditions. The electronic nature... 

The similarity should be noted between this reaction and the nucleophilic displacement reactions between alcohols and hydrohalic acids as discussed in Sections 14.3 and 14.4. In the Lucas test, the presence of zinc chloride, a Lewis acid, greatly increases the reactivity of alcohols toward hydrochloric acid. 

The issue of reaction conditions was addressed above in a previous chapter (DADP) but to summarize it, TATP forms at lower molar ratios of catalyst to acetone and with lower concentrations of catalyst [8]. The formation of chlorinated TATP (3-(chloromethyl)-3,6,6,9,9-pentamethyl-l,2,4,5,7,8-hexoxonane and 3,6-bis(chloromethyl)-3,6,9,9-tetramethyl-l,2,4,5,7,8-hexoxonane) was recently published by Matyas et al. when hydrochloric acid is used as a catalyst in very large excess. Other hydrohalic acids do not provide similar halogenated cyclic peroxides by this method TATP forms as a product of the following reaction [72]. 

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