Precautions hydrogen chloride

Hydrogen chloride. Method 1 from concentrated sulphuric acid and fused ammonium chloride). The most convenient procedure is to allow concentrated sulphuric acid to react with lumps of fused ammonium chloride in a Kipp s apparatus. The gas may be dried by passage through a wash bottle containing concentrated sulphuric acid the latter should be followed by an empty wash bottle or flask as a precaution against sucking back of the contents of the reaction vessel. 

Most hafnium compounds requite no special safety precautions because hafnium is nontoxic under normal exposure. Acidic compounds such as hafnium tetrachloride hydroly2e easily to form strongly acidic solutions and to release hydrogen chloride fumes, and these compounds must be handled properly. Whereas laboratory tests in which soluble hafnium compounds were injected into animals did show toxicity, feeding test results indicated essentially no toxicity when hafnium compounds were taken orally (33,34). 

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

Precautions should be taken to prevent absorption of atmospheric moisture by the hydrogen chloride solution. The dropping funnel should be closed or protected by a calcium chloride tube. 

However, it has been found that a by-product arising from the interaction of formaldehyde and hydrogen chloride is bis(chloromethyl)ether (BCME), which is a potent carcinogen. For this reason the classical chloromethylation route to side-chain halogenated products should not be regarded as a desirable synthetic procedure, and in general should only be used if the required compound cannot be readily prepared by other methods. When used, effective precautions should be taken during the reaction and in the disposal of the reaction residues.12 13... 

Diethyl phosphite is generally produced by the reaction of phosphorus (III) chloride with absolute alcohol. Good yields are difficult to obtain unless special precautions are taken. The by-product hydrogen chloride tends to react with the diethyl phosphite to form additional ethyl chloride and phosphorous acid ... 

The addition compound of trimethylamine and monochloro-borane was first synthesized by the reaction of gaseous hydrogen chloride with trimethylamine-borane at low temperature in a vacuum line. Although boron trichloride4 or mereury(II) chloride5 can be used, the first method can easily be modified for large-scale runs by using aqueous concentrated hydrochloric acid.5 No special precautions for the exclusion of air or water are necessary. 

Reaction step III is A-acyl at ion. It is conveniently carried out in a refluxing chlorinated aliphatic hydrocarbon the hydrogen chloride gas which is evolved should be scrubbed in aqueous caustic soda. Precautions are necessary when handling the highly corrosive chloroacetyl chloride. This step should be carried out in a glass lined reactor. 

An account of the elaborate research of Richards and Stahler 2 on potassium chloride appeared in 1907. The salt employed was prepared by the action of hydrogen chloride on potassium nitrate purified by repeated recrystallization with special precautions. After several crystallizations, the chloride was fused in a current of nitrogen. The silver was obtained by reducing the nitrate with ammonium formate. After electrolytic purification, it was fused in a lime-boat in a current of hydrogen, and finally in vacuo. In the analyses the silver required to precipitate the chlorine from a known weight of potassium chloride was determined, and also the weight of silver chloride produced ... 

Precautions and storage Hydrogen chloride should be stored in a cool, dry, well-ventilated area in tightly sealed containers and with a proper label. Containers of hydrogen chloride should be protected from physical damage and should be stored separately from hydroxides, amines, alkalis, or metals, such as copper, brass, zinc, potassium, and sodium. ... 

Observe normal precautions appropriate to the circumstances and quantity of material handled. Chlorocresol can be irritant to the skin, eyes, and mucous membranes. Eye protection, gloves, and protective clothing are recommended. Chlorocresol presents a slight fire hazard when exposed to heat or flame. It burns to produce highly toxic fumes containing phosgene and hydrogen chloride. 

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