Читать книгу Industrial Poisoning from Fumes, Gases and Poisons of Manufacturing Processes - Josef Rambousek - Страница 14

Carbon oxychloride (COCl₂, carbonyl dichloride, phosgene) is produced by direct combination of chlorine and carbonic oxide in presence of animal charcoal. Phosgene is itself a very poisonous gas which, in addition to the poisonous qualities of carbonic oxide (which have to be borne in mind in view of the method of manufacture), acts as an irritant of the mucous membranes. Commercially it is in solution in toluene and xylene, from which the gas is readily driven off by heating. It is used in the production of various colours, such as crystal violet, Victoria blue, auramine, &c.

A fatal case of phosgene gas poisoning in the report of the Union of Chemical Industry for 1905 deserves mention. The phosgene was kept in a liquefied state in iron bottles provided with a valve under 2·3 atm. pressure. The valve of one of these bottles leaked, allowing large escape into the workroom. Two workers tried but failed to secure the valve. The cylinder was therefore removed by a worker, by order of the manager, and placed in a cooling mixture, as phosgene boils at 8° C. The man in question wore a helmet into which air was pumped from the compressed air supply in the factory. As the helmet became obscured through moisture after five minutes the worker took it off. A foreman next put on the cleaned mask, and kept the cylinder surrounded with ice and salt for three-quarters of an hour, thus stopping the escape of gas. Meanwhile, the first worker had again entered the room, wearing a cloth soaked in dilute alcohol before his mouth, in order to take a sack of salt to the foreman. An hour and a half later he complained of being very ill, became worse during the night, and died the following morning. Although the deceased may have been extremely susceptible, the case affords sufficient proof of the dangerous nature of the gas, which in presence of moisture had decomposed into carbonic acid and hydrochloric acid; the latter had acutely attacked the mucous membrane of the respiratory passages and set up fatal bronchitis. Further, it was found that the leaden plugs of the valves had been eroded by the phosgene.

Three further cases of industrial phosgene poisoning have been reported,9 one a severe case in which there was bronchitis with blood-stained expectoration, great dyspnœa, and weakness of the heart’s action. The affected person was successfully treated with ether and oxygen inhalations. Phosgene may act either as the whole molecule, or is inhaled to such degree that the carbonic oxide element plays a part.

In another case of industrial phosgene poisoning the symptoms were those of severe irritation of the bronchial mucous membrane and difficulty of breathing.10 The case recovered, although sensitiveness of the air passages lasted a long time.

Carbon chlorine compounds (aliphatic series).—Methyl chloride (CH₃Cl) or chlormethane is prepared from methyl alcohol and hydrochloric acid (with chloride of zinc) or methyl alcohol, salt, and sulphuric acid. It is prepared in France on a large scale from beetroot vinasse by dry distillation of the evaporation residue. The distillate, which contains methyl alcohol, trimethylamine, and other methylated amines, is heated with hydrochloric acid; the methyl chloride so obtained is purified, dried and compressed. It is used in the preparation of pure chloroform, in the coal-tar dye industry, and in surgery (as a local anæsthetic). In the preparation of methyl chloride there is risk from methyl alcohol, trimethylamine, &c. Methyl chloride itself is injurious to health.

Methylene chloride (CH₂Cl₂, dichlormethane) is prepared in a similar way. It is very poisonous.

Carbon tetrachloride (CCl₄, tetrachlormethane) is technically important. It is prepared by passing chlorine gas into carbon bisulphide with antimony or aluminium chloride. Carbon tetrachloride is a liquid suitable for the extraction of fat or grease (as in chemical cleaning), and has the advantage of being non-inflammable. Carbon tetrachloride, so far as its poisonous qualities are concerned, is to be preferred to other extractives (see Carbon Bisulphide, Benzine, &c.); for the rest it causes unconsciousness similar to chloroform.

When manufactured industrially, in addition to the poisonous effect of chlorine, the poisonous carbon bisulphide has also to be borne in mind.

Ethyl chloride (C₂H₅Cl) is made in a way analogous to methyl chloride by the action of hydrochloric acid on ethyl alcohol and chloride of zinc. It is used in medicine as a narcotic.

Monochloracetic acid.—In the preparation of monochloracetic acid hydrochloric acid is developed in large quantity. From it and anthranilic acid artificial indigo is prepared (according to Heuman) by means of caustic potash.

Chloral (CCl₃CHO, trichloracetaldehyde) is produced by chlorinating alcohol. Chloral is used in the preparation of pure chloroform and (by addition of water) of chloral hydrate (trichloracetaldehyde hydrate), the well-known soporific.

Chloroform (CHCl₃, trichlormethane).—Some methods for the preparation of chloroform have been already mentioned (Chloral, Methyl Chloride). Technically it is prepared by distillation of alcohol or acetone with bleaching powder. The workers employed are said to be affected by the stupefying vapours. Further, there is the risk of chlorine gas from use of chloride of lime.

Chloride of nitrogen (NCl₃) is an oily, volatile, very explosive, strongly smelling substance, which irritates the eyes and nose violently and is in every respect dangerous; it is obtained from the action of chlorine or hypochlorous acid on sal-ammoniac. The poisonous nature of these substances may come into play. Risk of formation of chloride of nitrogen can arise in the production of gunpowder from nitre containing chlorine.

Cyanogen chloride (CNCl).—Cyanogen chloride is made from hydrocyanic acid or cyanide of mercury and chlorine. Cyanogen chloride itself is an extremely poisonous and irritating gas, and all the substances from which it is made are also poisonous. According to Albrecht cyanogen chloride can arise in the preparation of red prussiate of potash (by passage of chlorine gas into a solution of the yellow prussiate) if the solution is treated with chlorine in excess; the workers may thus be exposed to great danger.

Chlorobenzene.—In his paper referred to Leymann cites three cases of poisoning by chlorobenzene, one by dinitrochlorobenzene, and, further, three cases of burning by chlorobenzene and one by benzoyl chloride (C₆H₅COCl). The last named is made by treating benzaldehyde with chlorine, and irritates severely the mucous membranes, while decomposing into hydrochloric acid and benzoic acid.11 Benzal chloride (C₆H₅CHCl₂), benzo trichloride (C₆H₅CCl₃), and benzyl chloride (C₆H₅CH₂Cl) are obtained by action of chlorine on boiling toluene. The vapours of these volatile products irritate the respiratory passages. In the manufacture there is risk from the effect of chlorine gas and toluene vapour (see Benzene, Toluene).

Leymann12 describes in detail six cases of poisoning in persons employed in a chlorobenzene industry, of which two were due to nitrochlorobenzene. Symptoms of poisoning—headache, cyanosis, fainting, &c.—were noted in a person working for three weeks with chlorobenzene.13

In Lehmann’s opinion chlorine rash, the well-recognised skin affection of chlorine workers, may be due to contact with substances of the chlorbenzol group.14

Iodine and iodine compounds.—Formerly iodine was obtained almost exclusively from the liquor formed by lixiviation of the ash of seaweed (kelp, &c.); now the principal sources are the mother liquors from Chili saltpetre and other salt industries. From the concentrated liquor the iodine is set free by means of chlorine or oxidising substances and purified by distillation and sublimation. Iodine is used for the preparation of photographic and pharmaceutical preparations, especially iodoform (tri-iodomethane, CHI₃), which is made by acting with iodine and caustic potash on alcohol, aldehyde, acetone, &c.

Apart from possible injurious action of chlorine when used in the preparation of iodine, workers are exposed to the possibility of chronic iodine poisoning. According to Ascher15 irritation effects, nervous symptoms, and gastric ulceration occur in iodine manufacture and use. He considers that bromide of iodine used in photography produces these irritating effects most markedly. Layet and also Chevallier in older literature have made the same observations.

The Swiss Factory Inspectors’ Report for 1890-1 describes two acute cases of iodine poisoning in a factory where organic iodine compounds were made; one terminated fatally (severe cerebral symptoms, giddiness, diplopia, and collapse).

Bromine and bromine compounds.—Bromine is obtained (as in the case of iodine) principally from the mother liquors of salt works (especially Stassfurt saline deposits) by the action of chlorine or nascent oxygen on the bromides of the alkalis and alkaline earths in the liquors. They are chiefly used in photography (silver bromide), in medicine (potassium bromide, &c.), and in the coal-tar dye industry.

The danger of bromine poisoning (especially of the chronic form) is present in its manufacture and use, but there is no positive evidence of the appearance of the bromine rash among the workers. On the other hand, instances are recorded of poisoning by methyl bromide, and the injurious effect of bromide of iodine has been referred to.

Methyl iodide and methyl bromide.—Methyl iodide (CH₃I), a volatile fluid, is obtained by distillation of wood spirit with amorphous phosphorus and iodine; it is used in the production of methylated tar colours and for the production of various methylene compounds. Grandhomme describes, in the paper already referred to, six cases, some very severe, of poisoning by the vapour of methyl iodide among workers engaged in the preparation of antipyrin, which is obtained by the action of aceto-acetic ether on phenyl hydrazine, treatment of the pyrazolone so obtained with methyl iodide, and decomposition of the product with caustic soda. A case of methyl iodide poisoning is described in a factory operative, who showed symptoms similar to those described for methyl bromide except that the psychical disturbance was more marked.16

Three cases of methyl bromide (CH₃Br) poisoning are described in persons preparing the compound.17 One of these terminated fatally. There is some doubt as to whether these cases were really methyl bromide poisoning. But later cases of methyl bromide poisoning are known, and hence the dangerous nature of this chemical compound is undoubted. Thus the Report of the Union of Chemical Industry for 1904 gives the following instance: Two workers who had to deal with an ethereal solution of methyl bromide became ill with symptoms of alcoholic intoxication. One suffered for a long time from nervous excitability, attacks of giddiness, and drowsiness. Other cases of poisoning from methyl bromide vapour are recorded with severe nervous symptoms and even collapse.

Fluorine compounds.—Hydrogen fluoride (HFl) commercially is a watery solution, which is prepared by decomposition of powdered fluorspar by sulphuric acid in cast-iron vessels with lead hoods. The escaping fumes are collected in leaden condensers surrounded with water; sometimes to get a very pure product it is redistilled in platinum vessels.

Hydrogen fluoride is used in the preparation of the fluorides of antimony, of which antimony fluoride ammonium sulphate (SbFl₃(NH₄)₂SO₄) has wide use in dyeing as a substitute for tartar emetic. It is produced by dissolving oxide of antimony in hydrofluoric acid with addition of ammonium sulphate and subsequent concentration and crystallisation. Hydrofluoric acid is used for etching glass (see also Glass Industry).

In brewing, an unpurified silico-fluoric acid mixed with silicic acid, clay, oxide of iron, and oxide of zinc called Salufer is used as a disinfectant and preservative.

Hydrofluoric acid and silicofluoric acid (H₂SiFl₆) arise further in the superphosphate industry by the action of sulphuric acid on the phosphorites whereby silicofluoric acid is obtained as a bye-product (see also Manufacture of Artificial Manure). Hydrofluoric acid and its derivatives both in their manufacture and use and in the superphosphate industry affect the health of the workers.

If hydrogen fluoride or its compounds escape into the atmosphere they attack the respiratory passages and set up inflammation of the eyes; further, workers handling the watery solutions are prone to skin affections (ulceration).

The following are examples of the effects produced.18 A worker in an art establishment upset a bottle of hydrofluoric acid and wetted the inner side of a finger of the right hand. Although he immediately washed his hands, a painful inflammation with formation of blisters similar to a burn of the second degree came on within a few hours. The blister became infected and suppurated.

A man and his wife wished to obliterate the printing on the top of porcelain beer bottle stoppers with hydrofluoric acid. The man took a cloth, moistened a corner of it, and then rubbed the writing off. After a short time he noticed a slight burning sensation and stopped. His wife, who wore an old kid glove in doing the work, suffered from the same symptoms, the pain from which in the night became unbearable, and in spite of medical treatment gangrene of the finger-tips ensued. Healing took place with suppuration and loss of the finger-nails.

Injury of the respiratory passages by hydrofluoric acid has often been reported. In one factory for its manufacture the hydrofluoric acid vapour was so great that all the windows to a height of 8 metres were etched dull.

Several cases of poisoning by hydrofluoric acid were noted by me when examining the certificates of the Sick Insurance Society of Bohemia. In 1906 there were four due to inhalation of vapour of hydrofluoric acid in a hydrofluoric acid factory, with symptoms of corrosive action on the mucous membrane of the respiratory tract. In 1907 there was a severe case in the etching of glass.19