Methyl Alcohol

METHYL ALCOHOL, methanol (alcohol methylicus, carbinol, methanol, CH₃OH), was discovered by Taylor (Ph. Taylor, 1812) in the products of dry distillation of wood; it was studied more closely by Dumas and Peligot (1831). It is found in small quantities in the unripe fruits of Heracleum sphondylium, giganteum, Pastinaca sativa, Anthriscus cerefolium; the salicylic ester of methyl alcohol is contained in the essential oil of various species of Gaultheria, and then in species of Polygala, Coca, and other Ericaceae. In its pure form, it is a colorless, mobile liquid with a characteristic, peculiar odor and a burning, unpleasant taste; it boils at 64.7°; its specific gravity at 15° is 0.796; it is miscible in all proportions with water, ethyl alcohol, ether, fatty and essential oils; upon mixing with water, heating and a decrease in volume are observed. With anhydrous calcium chloride and other anhydrous chlorides, as well as with anhydrous barium oxide, methyl alcohol forms crystalline compounds that are easily decomposed by water. Metallic potassium and sodium react with methyl alcohol, forming potassium or sodium methylates (CH₃OK, CH₃ONa). Upon oxidation, methyl alcohol yields formaldehyde, formic acid, and carbonic acid. Methyl alcohol is obtained mainly from the aqueous part of the products of dry distillation of wood (pyroligneous acid), where it is contained in an amount of about 1%. From this, crude methyl alcohol (wood alcohol) is obtained by fractional distillation, containing acetone, methyl acetate, allyl alcohol, burnt substances, etc.; by distilling the crude product in column apparatuses, technically pure methyl alcohol is obtained, containing traces of acetone and acetaldehyde. Chemically pure methyl alcohol is obtained by converting it into methyl oxalate CH₃-O-CO-CO-O-CH₃, which is then decomposed with caustic alkali. At the present time, methyl alcohol is obtained in various countries in huge quantities by a cheaper synthetic method, by reducing carbon monoxide in water gas with the help of a catalyst (patent methods): CO + 2H₂ = CH₃OH. Methyl alcohol is used to obtain formalin, for the preparation of methyl esters of benzoic and anthranilic acids, methyl salicylate (Methylium salicylicum), and other medical or fragrant methyl derivatives; it is used in microscopy as a good fixing agent for blood smears, as well as an excellent (better than ethyl alcohol) solvent for stains (Giemsa, May-Grünwald) and celloidin. Crude methyl alcohol is used in industry for the preparation of varnishes, polishes, for combustion, lighting, for denaturing ethyl alcohol, etc. Methyl alcohol acts on the organism in an intoxicating manner and is very poisonous in large quantities; as a solvent of lipoids, methyl alcohol is a poison that paralyzes the central nervous system; therefore, it is not used at all in medicine for therapeutic purposes. Poisoning with methyl alcohol by ingestion in pure form is observed rarely; on the contrary, poisonings with methyl alcohol when using denatured alcohol (see) are relatively frequent. Regarding occupational poisonings, see below. In forensic-medical cases during toxicological-chemical examinations, methyl alcohol is distilled repeatedly several times (to purify the distillate) from urine, blood, intestines, stomach, or other organs. However, it must be noted that methyl alcohol disappears very quickly in the organism, and it is usually not found in corpses or only negligible amounts are found; instead, formic acid is more often found, which is also contained in the organism normally. Only large quantities of formic acid can serve as an indirect indication of poisoning with methyl alcohol. In wines, tinctures, liqueurs, cologne, etc., repeated distillation is also used to isolate methyl alcohol to obtain the purest possible methyl alcohol, even if only in the amount of a few cm³ or even drops. The distillate is oxidized (carefully) with potassium permanganate so that the reaction proceeds only to the production of formaldehyde, and the presence of the latter is established (best of all) by the reaction with sulfuric acid and morphine: a violet to blue-violet coloration. It is also good to use fuchsin-sulfurous acid to detect formalin; at the same time, a control (blank) experiment must be performed with 10% ethyl alcohol. Autenrieth indicated a method for detecting methyl alcohol by converting it into the methyl ester of p-bromobenzoic acid, BrC₆H₄COOCH₃, by the action of p-bromobenzoyl chloride in the presence of alkali; the methyl ester is a solid crystalline body (melting point 78-79°), which distinguishes it from ethyl and other higher homologs. Quantitative determination, with sufficient quantities of methyl alcohol, can be performed by the specific gravity of the distillate, which is previously freed from volatile acids and essential oils by extracting them with petroleum ether. Heiduschka and Wolf oxidize methyl alcohol with a mixture of sulfuric acid and potassium dichromate and capture the combustion product-CO₂-in a weighed potash bulb. Extremely small quantities of methyl alcohol, e.g., "natural" methyl alcohol during the fermentation of fruit wines, are determined colorimetrically with fuchsin-sulfurous acid according to Fellenberg in the oxidized (to formalin) distillate. To determine methyl alcohol in the air during occupational poisonings, 200-300 liters or more of air are drawn through 5-6 washing bottles (e.g., Drechsel bottles) with water using an aspirator, and then qualitative and quantitative determinations of methyl alcohol are performed in this water by one of the indicated methods. N. Kornilov. From the point of view of occupational hygiene, methyl alcohol finds fairly wide application in industry both in the form of crude wood alcohol and in the form of purified (refined) methyl alcohol and various distillates obtained during rectification with a significant content of acetone (called acetonized alcohols). Pure methyl alcohol is used mainly in the chemical-pharmaceutical industry (in the production of chloromethyl, dichloromethane, methyl iodide, in the production of synthetic codeine, etc.). Acetonized alcohols have the greatest use in the industry of the USSR, entering as solvents into the composition of varnishes, polishes, mastics (in the paint and varnish industry), and adhesive compositions (in the shoe industry). Acetonized alcohols consist mainly of acetone and methyl alcohol and contain, in addition, methyl acetate and various impurities (aldehydes, allyl and propyl alcohol, etc.); they are called, depending on the percentage content of acetone in them, 40%, 60%, or 25% acetonized alcohol. The lower the percentage of acetone, the higher the content of methyl alcohol in them. The composition of varnishes, polishes, mastics, enamels, and adhesive compositions includes mostly 40% or 60% acetonized alcohol, and 25% or 20% acetonized alcohol is used together with turpentine for the denaturation of ethyl alcohol. Although impurities in methyl alcohol can have some significance, especially in relation to the irritating effect on mucous membranes (e.g., allyl alcohol), a number of authors believe that the main cause of poisonings is methyl alcohol itself, and not the impurities contaminating it. Thus, Sollmann, on the basis of experiments on rats with pure methyl alcohol, wood alcohol, and methyl alcohol containing impurities, came to the conclusion that the impurities contaminating methyl alcohol play only an insignificant role in poisonings, whereas methyl alcohol is a definitely poisonous substance. Rost, Braun, and Reif hold the same opinion. From the point of view of occupational hygiene, the inhalation of methyl alcohol vapors is of the greatest importance. The work of Müller and especially Loewy and Heide has clarified the question of the action of methyl alcohol when its vapors are inhaled. These authors proved that even at a low concentration of methyl alcohol in the inhaled air (0.15-0.2%), it passes into the organism of experimental animals in such quantities that it can be quantitatively determined in the body. With increasing tension of methyl alcohol vapors in the inhaled air, the amounts of methyl alcohol accumulating in the body also increase. Methyl alcohol easily passes from the lungs and accumulates in the body of experimental animals (in rats up to 50-88%, in dogs at higher tension-only up to 7-8%). Langgaard, Nicloux, and Placet established that methyl alcohol, given repeatedly in small quantities, causes a cumulative effect. Accumulating in the organism, it undergoes slow oxidation to formic acid. According to Harnack, methyl alcohol, introduced into the organism due to specific molecular affinity for certain parts of the central nervous system and especially for the nerve elements of the retina and the optic nerve, undergoes slow oxidation to formic acid in these places, due to which these very areas turn out to be the most severely affected. Nicloux and Placet also explain the particularly high toxicity of methyl alcohol by its slow oxidation in the organism. Recently, serious importance is also attached to the formation of formaldehyde as an intermediate product of the transformation of methyl alcohol (Kelser). In dogs, methyl alcohol does not disappear from the organism even after 5 days. Koelsch, on the basis of a critical review of extensive literature, believes that the toxic effect of methyl alcohol is due to its slow oxidation; he explains the exceptional versatility of the clinical picture of methyl alcohol poisoning by the fact that the organism's reaction depends on its ability to oxidize methyl alcohol.

The local effect of methyl alcohol manifests as irritation of the mucous membranes of the respiratory tract and the conjunctiva of the eyes; the general effect manifests as headaches, dizziness, tinnitus, convulsions, visual disturbances (up to blindness), nausea, and vomiting. Koelsch notes that in this mostly chronic poisoning, a sudden exacerbation often occurs. The visual disturbances observed very frequently in methyl alcohol poisoning, described in detail by a number of authors (Bab, Birch-Hirschfeld, Kazas, Loginov), are expressed in disorders of accommodation, narrowing of the visual field, scotomas, and blindness. Koelsch notes that dilation and immobility of the pupil are often the first or even the only sign. The refractive media appear unchanged; there is damage to the optic nerve and retina. I. I. Kazas established the independence of diseases of both the retina and the optic nerve. The general picture of retinal changes consists of a degenerative process and edematous infiltration. In the optic nerve, he did not detect any inflammatory phenomena during his experimental work on 40 rabbits regarding acute and chronic methyl alcohol poisoning; in all experiments, atrophy of the optic nerve was clearly expressed. With visual disturbances, restitutio ad integrum is extremely rare; on the contrary, deteriorations leading to total blindness are observed. Personal sensitivity is extremely variable. Koelsch reports that in some cases, a single exposure to methyl alcohol in the form of vapors or through absorption from the skin caused blindness. Mostly, serious disorders occur after repeated exposure, especially under unfavorable hygienic conditions (high temperature, cramped room with insufficient ventilation). Occupational methyl alcohol poisonings occur both in the production of methyl alcohol itself and in those industries where it is used in pure form or in the form of acetone alcohols, varnishes, enamels, zapon varnishes, polishes, shoe glue, lubricating solutions, etc. This takes place in the woodworking and furniture industry (painters, varnishers), in pencil factories, in the dyeing business, the chemical industry, and in shoe factories. A number of severe cases of poisoning with subsequent blindness have been noted among painters, during the cleaning of old furniture (with pure methyl alcohol), during the coating of beer barrels on the inside with a shellac solution containing 50% methyl alcohol, etc. Baskerville collected data on 64 cases of methyl alcohol poisoning that occurred in America from the inhalation of its vapors; occupational poisonings were observed among painters and varnishers. These observations are of serious importance, since according to Efremov's data, acetone alcohol is included in the composition of pencil varnishes in an amount of 33-39%, and zapon varnishes and enamels for coating metal products contain up to 20% methyl alcohol. In addition to the general resorptive effect, one must also note the harmful effect of methyl alcohol on the skin, which is also observed when working with pure methyl alcohol, wood alcohol, and the substances listed above, which contain methyl alcohol. There are especially many indications in the reports of factory inspectors in Germany regarding skin diseases when working with polish made from alcohol denatured with methyl alcohol. In Germany, when using a 2% solution of methyl alcohol and a 0.5% solution of pyridine as a denaturing agent, numerous cases of skin diseases, phenomena of irritation of the mucous membranes, and a number of general nervous symptoms were observed. According to Koelsch, skin diseases (especially often observed in furniture and cane polishers and bearing the name of polishers' eczema—das Polierekzem) are localized most often in the interdigital folds, on the back of the hand, and on the forearm up to the elbow bend; this rash proceeds in the form of highly itchy eczema with phenomena of acute dermatitis (redness, swelling of the skin, weeping areas), passing with proper treatment in 2-3 weeks, but distinguished by a tendency to recur. It can in these cases last for months and become chronic. Koelsch observed 9 cases of skin diseases among 72 polishers at a small furniture factory. In the factory inspector's report for 1910/11 for Königsberg, among 34 polishers at the 1st furniture factory, 35 cases of eczema were observed over 1 year and 9 months, and in the following year, among 25 polishers, 31 cases. In Austria, according to an international review of occupational diseases for 1910, among 1,328 workers constantly working with polish, 25 had eczema. At Moscow furniture factories, cases of occupational skin diseases were observed when using alcohol denatured with methyl alcohol and turpentine. With six months of experience using polish made from raw alcohol at one of the furniture factories, no cases of skin diseases were observed. Health measures: replacement of methyl alcohol with other solvents in all cases where this is possible. Complete prohibition of the use of methyl alcohol for denaturing alcohol and especially regarding polish for furniture factories (where polishers heavily contaminate the entire hand and even the forearm with polish). Hermetic sealing of all production processes during which methyl alcohol vapors can be released, and mechanization of the pouring of methyl alcohol or solutions containing methyl alcohol. Increased ventilation is necessary in all rooms where evaporation of solutions containing methyl alcohol occurs. It is necessary to take measures to combat high temperature in rooms where methyl alcohol can evaporate. A preliminary medical examination of those working with methyl alcohol and periodic repeat medical examinations are necessary. Treatment of methyl alcohol poisoning—SEE Poisoning.

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