Hydrogen chloride gas

An acid was once defined simply as a substance which produces hydrogen ions, or protons. However, the simple proton, H , is never found under ordinary conditions, and this definition required amendment. Bronsted and, independently, Lowry, therefore redefined an acid as a susbstance able to donate protons to other molecules or ions, and a base as a substance capable of accepting such protons. If we consider hydrogen chloride, HCl, as an example, the HCl molecule is essentially covalent, and hydrogen chloride (gas or liquid) contains no protons. But anhydrous hydrogen chloride in benzene will react with anhydrous ammonia ... 

However, hydrogen chloride gas, obtained as a by-product in chlorination reactions, is commercially converted to chlorine by passing the hydrogen chloride mixed with air over a copper catalyst at a temperature of 600-670K when the following reaction occurs ... 

The tribromobenzene obtained in this way should be entirely free from unchanged tribromoaniline. To test its purity, dissolve a small quantity in hot dry benzene and pass in hydrogen chloride gas from a Kipp s apparatus no trace of crystals of tribromoaniline hydrochloride should appear. Note also that although the m.p.s of the two compounds are almost identical, that of the recrystallised product from the above preparation is considerably depressed by admixture with tribromoaniline. 

An alternative method of conducting the preparation consists in treating 100 g. of cycZohexanol with 250 ml. of concentrated hydrochloric acid, refluxing slowly whilst a stream of hydrogen chloride gas is passed into the mechanically stirred... 

Into a 500 ml. three-necked flask, provided with a mechanical stirrer, a gas inlet tube and a reflux condenser, place 57 g. of anhydrous stannous chloride (Section 11,50,11) and 200 ml. of anhydrous ether. Pass in dry hydrogen chloride gas (Section 11,48,1) until the mixture is saturated and separates into two layers the lower viscous layer consists of stannous chloride dissolved in ethereal hydrogen chloride. Set the stirrer in motion and add 19 5 g. of n-amyl cyanide (Sections III,112 and III,113) through the separatory funnel. Separation of the crystalline aldimine hydrochloride commences after a few minutes continue the stirring for 15 minutes. Filter oflF the crystalline solid, suspend it in about 50 ml. of water and heat under reflux until it is completely hydrolysed. Allow to cool and extract with ether dry the ethereal extract with anhydrous magnesium or calcium sulphate and remove the ether slowly (Fig. II, 13, 4, but with the distilling flask replaced by a Claisen flask with fractionating side arm). Finally, distil the residue and collect the n-hexaldehyde at 127-129°. The yield is 19 g. 

Dissolve 2 ml. of acetaldehyde in 5 ml. of dry ether, cool in a freezing mixture of ice and salt, and pass in dry hydrogen chloride gas for 30-60 seconds. The solid polymer, metaldehyde, may separate in a short time, otherwise cork the tube and allow it to stand for 10-15 minutes. Filter ofiF the crystals. 

To prepare the solid phenyldlazonlum chloride or sulphate, the reaction is conducted in the absence of water as far as possible. Thus the source of nitrous acid is one of its organic esters (e.g., amyl nitrite) and a solution of hydrogen chloride gas in absolute alcohol upon the addition of ether only the diazonium salt is precipitated as a crystalline solid, for example ... 

In a 500 ml. conical flask place 50 ml. of glachtl acetic acid, 25 ml. of 40 per cent, formaldehyde solution (formalin) and 20 g. of phenol. Wrap a cloth or towel loosely around the neck and opening of the flask. Pass dry hydrogen chloride gas (Section 11,48,1) into the mixture. Within 5 minutes, a large mass of pink plastic is formed the reaction is sometimes very vigorous. The yield is 36 g. It is frequently necessary to break the flask in order to remove the product completely for this reason a beaker, or metal flask or beaker, is preferable. 

The primary use for 2,4-di-/ f2 -butylphenol is in the production of substituted triaryl phosphites. 2,4-Di-/ f2 -butylphenol reacts with phosphoms trichloride typically using a trialkylamine or quaternary ammonium salt as the catalyst. Hydrogen chloride is formed and either complexed with the amine or Hberated as free hydrogen chloride gas forming the phosphite ester, tris(2,4-di-/ f2 -butylphenyl)phosphite [31570-04-4] (58). The phosphite-based on... 

A BrasiHan company has reportedly produced ammonium chloride from hydrogen chloride gas (16). Hydrogen chloride is mixed with air and iatroduced iato a saturated ammonium chloride suspension at 80 °C. Excess ammonia is added to a conical section of the saturator to maintain a pH of 8. The ammonium chloride is recovered from the suspension by thickening ia a hydroclone, foUowed by centrifugation and dryiag. Mother Hquor and the water used to scmb waste gases, are returned to the saturator. 

Trichlorosilane. The primary production process for trichlorosilane is the direct reaction of hydrogen chloride gas and sihcon metal in a fluid-bed reactor. Although this process produces both trichlorosilane and sihcon tetrachloride, production of the latter can be minimi2ed by proper control of the reaction temperature (22). A significant amount of trichlorosilane is also produced by thermal rearrangement of sihcon tetrachloride in the presence of hydrogen gas and sihcon. 

Anhydrous stannous chloride, a water-soluble white soHd, is the most economical source of stannous tin and is especially important in redox and plating reactions. Preparation of the anhydrous salt may be by direct reaction of chlorine and molten tin, heating tin in hydrogen chloride gas, or reducing stannic chloride solution with tin metal, followed by dehydration. It is soluble in a number of organic solvents (g/100 g solvent at 23°C) acetone 42.7, ethyl alcohol 54.4, methyl isobutyl carbinol 10.45, isopropyl alcohol 9.61, methyl ethyl ketone 9.43 isoamyl acetate 3.76, diethyl ether 0.49, and mineral spirits 0.03 it is insoluble in petroleum naphtha and xylene (2). 

Modem plants manufacture chlorosulfuric acid by direct union of equimolar quantities of sulfur trioxide and dry hydrogen chloride gas. The reaction takes place spontaneously with evolution of a large quantity of heat. Heat removal is necessary to maintain the temperature at 50—80°C and thus minimize unwanted side reactions. The sulfur trioxide may be in the form of 100% Hquid or gas, as obtained from boiling oleum, ie, fuming sulfuric acid, or may be present as a dilute gaseous mixture as obtained direcdy from a contact sulfuric acid plant (24). The hydrogen chloride gas can be in the form of 100% gas or in a diluted form. 

Some special precautions for use of compressed hydrogen chloride gas include ... 

Chemical Reactivity - Reactivity with Water. Reacts violently with water, liberating hydrogen chloride gas and heat Reactivity with Common Materials None if dry. If wet it attacks metals because of hydrochloric acid formed flammable hydrogen is formed Stability During Transport Stable if kept dry and protected from atmospheric moisture Neutralizing Agents for Acids and Caustics Hydrochloric acid formed by reaction with water can be flushed away with water. Rinse with sodium bicarbonate or lime solution Polymerization Not pertinent Inhibitor of Polymerization Not pertinent. 

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