Benzine

BENZINE, Benzinum, the original name for benzene, given by Mitscherlich in 1833. At present, B. is called mixtures of hydrocarbons, the boiling point of which lies between 70 and 120°. A distinction is made between coal-tar and petroleum, or petrol, B. Coal-tar B. is obtained by distillation of light coal-tar oil, which is obtained in the dry distillation of coal; it consists mainly of benzene (30-50%), toluene (40% and more), xylene (up to 11% and more), and a small amount of cumene, cymene, and other higher aromatic hydrocarbons. Coal-tar B. is transparent, colorless as water, strongly refracts light, and has an aromatic odor. The specific gravity of coal-tar B. at 15° is 0.87-0.88. The more benzene it contains, the more valuable coal-tar B. is considered. For the detection of coal-tar B., the air or liquid under examination is treated with nitric acid; in the presence of coal-tar B., nitrobenzene is formed, which has a sharp smell of bitter almonds. Petroleum B., Benzinum Petrolei, ordinary B., is the low-boiling fractions (up to 150°) of petroleum distillation. Depending on the origin of the petroleum, the composition of B. includes low-boiling saturated hydrocarbons (paraffins), unsaturated (olefins), naphthenes (cycloparaffins and cycloolefins), and sometimes also hydrocarbons of the benzene series. Purified B. is transparent and has a weak, not unpleasant, petroleum odor. Commercial grades of B. are usually divided into light-specific gravity 0.64-0.66, medium-specific gravity 0.66-0.72, and heavy-specific gravity 0.72-0.77. In technology, B. is widely used as a solvent, as fuel for internal combustion engines (automobiles, airplanes, etc.), in rubber goods factories, in laundries, and so on. Pharmacopoeia (VII) adopted petroleum B. with a specific gravity from 0.666 to 0.686; it is soluble in 5-6 volumes of 90% alcohol. The fraction of petroleum benzine obtained from petroleum gases, with a specific gravity of 0.60-0.62, and known under the name of rigolene (or zymogene), boils slightly above 0° and is used for local anesthesia. The fractions of light petroleum B., or petroleum ether-specific gravity 0.64-0.66, and medium B.-specific gravity 0.70-have application in analytical practice and in productions for the extraction of fats, essential oils, alkaloids, etc. Heavy B.-specific gravity 0.720-0.730-is called ligroin. In microtechnique, B. is used because of its ability to easily dissolve chloroform, ether, fatty oils, paraffin, resins, and balsams. It can serve as an intermediate medium when embedding in paraffin. It is recommended for cleaning immersion objectives from cedar oil.

N. Kornilov. Benzine from the perspective of occupational hygiene. Benzine is one of the most serious industrial poisons, causing a significant number of professional poisonings. For example, in 1923-26 in Moscow, in the chemical industry, there were 142 cases of B. poisoning, or 34.6% of all registered poisonings. A feature of professional B. poisoning is often their mass character. The mass poisoning of female workers that occurred in 1914 at the 'Provodnik' factories in Riga and 'Treugolnik' in Petersburg were, according to the conclusion of a government commission, directly linked to the inhalation of B. vapors. A mild poisoning in 1924 of 133 female workers in the galosh department of the 'Bogatyr' factory was also caused by the inhal of large quantities of B. vapors that had accumulated in the air of the workshop due to the stoppage of exhaust ventilation. To this day, it cannot be considered definitively established whether such poisonings are purely acute, or whether there is an intensification of chronic poisonings and neurasthenic-hysterical conditions of workers and female workers, which is also linked to constant inhalation of B. vapors. Besides rubber production, where B. is used as the main component of 'rubber cement' and affects two main professional groups-'mazilitsy and galoshnitsy' (according to data from Prof. Okunevsky, in 1923 in the galosh workshop of the 'Krasny Treugolnik' factory in 1 liter of air there was 9.9 mg of B., and in the mazilitsy workshop-28.4 mg), B. is also used in the following productions: at oil fields, at oil refineries (in Baku in 1925-26 in the kerosene-oil departments, vapors of B.-like hydrocarbons were found in different departments from 1.2 to 8.1 mg per liter of air), in petroleum product warehouses, in oil shops, in chemical cleaning of clothing and fabrics, in the production of various paints and varnishes (particularly recently in the aviation industry), in the extraction of oils from seeds, in the production of linoleum, oilcloth and other rubberized fabrics, in carbureting illuminating gas, in servicing internal combustion engines in garages, etc. B. penetrates the body, mainly, through the respiratory organs; partial penetration through the skin, even undamaged (as a result of preliminary dissolution of skin fat), is also possible. The toxic dose of B. cannot be precisely established, since B. is not a homogeneous chemical substance. Not to mention impurities of benzene and other its derivatives, B. has a different composition depending on the place of oil extraction, the first fraction of which it represents. Light B. (in which there are fewer compounds of the aromatic series) are 1¹/₂-2 times less toxic than heavy ones. Data from authors about toxic doses of B. are little reliable, since they are based either on experiments conducted on animals or on comparison with the more studied benzene. Felix (Phelix, 1872), conducting experiments on convicts, obtained the first symptoms of poisoning when inhaling 3-15 g of B. in 7-15 minutes and complete narcosis when inhaling 20-40 g. Lehmann obtained death of cats in 2 hours with 200 mg of B. per 1l; 45 mg kills the animal in 2 hours, 200 mg-in 1 hour. In humans, 45 mg per 1 l gave the first signs of effect on the central nervous system. Kravkov obtained in white mice violent poisoning, ending in death after several minutes-with 100-300 mg of B. per 1 l and severe poisoning phenomena-with 50-60 mg per 1 l. Kravkov and Okunevsky consider 2 mg per 1 l the maximum allowable dose, and the hygienic norm-0.5 mg per 1 l. The State Institute for Labor Protection (Moscow) proposes as the allowable concentration of B. in the air of industrial enterprises (taking into account the danger of chronic poisonings)-0.2-0.4 mg per 1 l. Poisoning by B. can be acute and chronic. Acute poisonings can have varying intensity, up to immediate death (for example, when cleaning tanks and tank cars). When inhaling large quantities of B. vapors, its narcotic effect quickly manifests itself-loss of consciousness (sometimes after a brief excitation, often with a cry), rapid, shallow and incorrect breathing, small and rapid pulse, vomiting, weakening or disappearance of reflexes, sometimes convulsive muscle contractions. When inhaling small doses of B. vapors, the picture of poisoning usually has the character of excitation: a state of intoxication is observed, unreasoned laughter, often turning into tears, hysterical outcries, hallucinations; dizziness, dryness in the throat, nausea, vomiting, fleeting pains throughout the body, weakness in the legs, tremor, muscle twitching, protein appears in the urine, disturbances from the liver (enlargement, soreness, yellowish color, urobilin in the urine), blood pressure rises. Sometimes the local action of B. also manifests itself (irritation of the mucous membranes of the eyes, nose, upper respiratory tract).- Chronic phenomena of poisoning are sometimes as if consequences of acute poisoning, sometimes they arise independently. After acute poisonings, even if of small intensity, neurasthenia often remains, sometimes with typical hysterical seizures, instability of the psyche, weakening of mental activity and generally of working capacity, change of character, neuritis, lowering and even disappearance of reflexes, lowering of sensitivity, weakening of cardiac activity, dyspeptic phenomena, catarrhal condition of the respiratory tract, menstrual disorders, etc. One of the most characteristic signs of B. poisoning is anemia as a result of damage to the blood-forming function. According to data obtained in the Moscow clinic of social and professional diseases as a result of mass examination in 1923-25 of galoshnitsy of the 'Bogatyr' factory, the weight of galoshnitsy is significantly less than that of the control group. 70% of galoshnitsy have less than 60% Hb, 81.4% less than 4 million erythrocytes, a significant number have a reduced color index, polychromasia is often encountered; in 18.2%-basophilic granularity of erythrocytes, shift of neutrophils to the left, lymphopenia and eosinophilia; hysteria in 22.4%, lowering of sensitivity of fingers of hands in 50.6%, nerve points of Cornelius in 81.9%; in mazilitsy-39.2% myocarditis and 29.9% arteriosclerosis, dysmenorrhea as a common phenomenon (in pregnant women, the damage is especially severe).- Prolonged contact with B. apparently, as in experimental animals, so in workers, develops habituation to it. The mechanism of action of B. has not yet been finally clarified. Lehmann believes that B. disrupts oxidative processes in the central nervous system. Flory recognizes B. exclusively as a poison of the nervous system, which corresponds to the observations of Russian authors (Shustrov, Salistovskaya and Letavet), who, on the basis of their experimental work, put forward the dissolution of lipoids in tissues and organs by benzine (hemolytic action and selective action on the central nervous system, rich in lipoids).- Preventive measures: 1) control over the purity of B., over its minimal content of benzene (up to 1%) and other aromatic compounds; 2) replacement of B. with less toxic or at least less volatile hydrocarbons (benzinoform, trichloroethylene, etc.); 3) not allowing high temperatures in the workplace; 4) isolation of processes with significant release of B. into separate rooms; 5) removal of B. vapors at their place of formation; 6) rationally arranged general ventilation with supply of fresh air and ensuring sufficient exchange (at least threefold) and ensuring its normal, uninterrupted functioning; 7) sufficient cubic capacity (at least 20 cubic m per 1 worker); 8) observance of special precautions when cleaning tank cars, tanks, etc. (preliminary thorough ventilation, testing on small animals- white rats); 9) regular medical examinations of workers (especially in relation to the nervous system and blood); 10) not allowing to work persons with diseases of the nervous system (organic or functional), blood-forming organs and liver.