From Big Medical Encyclopedia

PERCHLOROMETHANE (phenoxin; a synonym freon 10) — the elementary carbon compound with chlorine, CC14, the strongest hepatotropic poison. H at. apply to receiving hladon (freon), in organic synthesis in laboratory and industrial conditions as a fire extinguishing means, for chemical cleaning and other purposes. Because of high toxicity of Ch. at. carry to industrial poisons (see Poisons industrial). In experimental medicine of Ch. at. apply to modeling of geiatopatiya on animals (see Cirrhosis, a pathogeny).

H at. — the heavy colorless liquid, g°pl is equal — 22,96 °, t°mm 76,75 °, relative density at 20 ° — [d] * ° — is equal 1,595, water solubility makes 0,08%, mixes up with the majority of organic solvents. H at. gives constant boiling mixtures (see) with water, methanol and nek-ry other liquids, dissolves many organic matters, including fats (see), wax (see), pitches, etc. At a usual temperature of Ch. at. it is chemically quite inert, at a temperature over 500 ° is oxidized with formation of phosgene (see. Suffocating toxic agents). Wet Ch. at. korrodirut metals (iron, aluminum), decaying to C02 carbon dioxide and

HC1 hydrogen chloride; Ch.'s contact is inadmissible at. with alkali metals (explosion is possible). With sulphuric anhydride (oleum) of Ch. at. reacts on the equation:

CC14 - >f 2S03-COC12 + S205CI2;

this reaction is used for a lab. receiving phosgene. As tetrachlorine-anhydride ortho-carbonic to - you S(ON perchloromethane turns into orthocarbonates:

with olefins it reacts telomerizations (chain reaction of unsaturated organic compounds in the presence of substances - transfer - chikov with formation of mix of low-molecular homologs), used in industrial organic synthesis. In the equipment Ch. at. receive chlorination of hydrocarbons (see) or their chlorderivatives and carbon sulfur and other ways.

The mechanism of a specific hepatotoxic action of Ch. at. explain with influence of the free radical (see Radicals free):

The formed free radical is capable to damage directly fermental systems, napr, system of R-450 cytochrome of a liver (see Tsitokhroma). It can also have pro-oxidatic effect, i.e. initiate chain reaction (see. Chain reactions) of peroxide oxidation of lipids (see Peroxides) that leads to structural and functional reorganization biol. membranes (see Membranes biological), their permeability for ions of H+, K+, Na+, Sa2 + with the subsequent space dissociation of oxidizing chains increases. At last, cytoplasmic membranes are broken off with an exit of proteolytic enzymes, and the cell (hepatocyte) perishes that is clinically shown by a syndrome of a cytolysis (see. Liver failure).

Perchloromethane as professional harm. The prof. of poisoning of Ch. at. are possible at intake of vapors of poison through respiratory tracts, Ch.'s reception at. inside or at its long contact with skin.

Hron. Ch.'s poisoning at. it is characterized by a memory impairment, drowsiness, inertness and other manifestations of an initial stage of hepatogenous encephalopathy (see), disturbances of cordial activity and dysuric frustration. The liver is increased and painful, broken motility and a peristaltics of intestines, note spasms of its various departments. Early objective symptoms hron. Ch.'s poisonings at. consider positive reaction Wang - den - Berg (see Wang - den - Berg reaction), jaundice (see) in a latent or explicit form, decrease in concentration of calcium (see) in blood, increase in content of urobilin (see) and urobilinigen, a giperbilirubiiyemiya (see), a lymphocytosis. In blood serum note increase in activity of specific aminotransferases (see) and other enzymes (see}, first of all — microsomal, the hyperferremia, a prothrombinopenia is observed. Synthetic function of a liver suffers — synthesis of glucuronides is broken (see); bilirubin (see) and serum proteins. At Ch.'s action at. on skin there can be dermatitis (see), sometimes eczema (see).

Acute poisoning of Ch. at. is followed by a severe headache, dizziness, confusion or a loss of consciousness. In hard cases the liver failure quickly develops (see) and victims can die at the phenomena of a hepatic coma (see). Sometimes acute poisoning of Ch. at. has character of encephalomyelitis (see), cerebellar dystrophy (see the Cerebellum), peripheral neuritis (see), note epileptiform spasms (see). At slowly developing poisoning to these a wedge, to manifestations symptoms of further damage of a liver and kidneys, vomiting, a diarrhea, sharply expressed jaundice join. The liver is increased and painful, the oliguria is noted, in urine find protein, erythrocytes, cylinders. In blood concentration of residual nitrogen increases (see residual nitrogen), the content of chlorides decreases, the content of calcium, serum proteins continues to decrease.

Damage of a liver has character of a fatty hepatosis (see): note fatty infiltration, centrolobular necroses, hemorrhages and leukocytic infiltration of a parenchyma, development of an acute massive necrosis is possible.

First aid and emergency treatment. The victim needs to be brought to the warm aired placement or on fresh air, to provide rest, heat, inhalation of the moistened oxygen. Intravenously enter 20 ml of 40% of solution of glucose from 500 mg ascorbic to - you, kapelno — 0,5 — 1 l of 10 — 15% of solution of glucose; intramusculary — 40 — 50 mg

of V1t 2 vitamin of ml of 30% of solution of vitamin E (tocopherol of acetate) 3 — 4 times, 10 ml of 5% of solution of Unithiolum 4 times a day, lipoic to - that to 750 — 1000 mg a day, subcutaneously — 5 — 10 PIECES of insulin. The diathermy on area of kidneys gives good effect, according to indications appoint cardiacs (Corazolum, Cordiaminum).

In hard cases of poisoning apply a hemodialysis (see), according to indications if there is no fluid lungs, make an artificial respiration (see), adrenaline is absolutely contraindicated! At peroral poisoning it is required to enter immediately inside apprx. 150 — 200 ml of liquid or castor oil, to make a gastric lavage (see), to give salt ate * bitelny. For the rest — the actions which are listed above. The victim needs to be hospitalized urgently.

Further treatment at acute poisoning of Ch. at., as well as at chronic — symptomatic.

Examination of working capacity. Questions of examination of working capacity, medical and labor rehabilitation at Ch.'s poisoning at. decide taking into account expressiveness a wedge, symptoms of intoxication and a gigabyte. characteristics of working conditions, After acute and hron. poisonings of victims transfer to other work for all the time of treatment. At establishment of hypersensitivity to Ch. at. or at a serious poisoning with existence of the residual phenomena of intoxication (development hron. hepatitis, cirrhosis, damage of kidneys), the victim is discharged of work with perchloromethane and provide rational employment.

Prevention of poisonings with l, tetrachloride at, e r about d about m consists in - mechanization and automation of handworks on the corresponding productions, sealing of the equipment, improvement of ventilation (see), a gigabyte. standardization of raw materials. Use of individual protection equipment of a respiratory organs and skin is of great importance (see Gas masks, Clothes special). It is obligatory preliminary and periodic medical examinations (see Meduli insky survey).

Maximum allowable concentration of Ch. at. in air of a working zone of 20 mg/m3, in air of the inhabited places of 4 mg/m3 (most one-time) and 0,7 mg! m3 (average daily), in water of reservoirs of economic and drinking and cultural and community use of 0,3 mg/l.

Perchloromethane in the medicolegal relation. In court. - medical practice fatal poisonings of Ch. at. meet quite seldom, generally as result of the negligent treatment of him in life either on production, or at the wrong use of Ch. at. instead of alcoholic drinks. A lethal dose of Ch. at. at peroral poisoning makes from 20 to 50 ml.

Morfol. the changes revealed on opening at Ch. which died from poisoning at., depend on a way of intake of poison to an organism and life expectancies of the reception of poison which was injured later. At the inhalation poisoning which is quickly leading to death only the sharp plethora of internals, toxic hypostasis and acute emphysema of lungs, small hemorrhages in substance of a brain is defined. At peroral hit of Ch. at. in an organism and approach of death in several days after hit of poison in an organism find characteristic icteric coloring of skin and scleras, small dot and larger hemorrhages under a meninx and in substance of a brain, and also in a myocardium, kidneys, a stomach, intestines. The centers of a necrosis in a pancreas, acute stomach ulcers and a duodenum, severe damage of a liver — its sharp increase (till 2500) with a picture of a fatty hepatosis come to light. Dystrophic changes of kidneys up to a necrotic nephrosis are noted, in gleams of renal tubules rozetkovidny crystals of oxalates come to light.

At court. - a chemical research Ch. at. from biol. material take wet distillation. Ch.'s presence at. at the received distillate establish by elimination reaction of chlorine during the heating with caustic alkali (an ion of C1“ find reaction with silver nitrate), reaction of formation of an isonitrile during the heating with aniline and caustic alkali, emergence of pink coloring during the heating of distillate with resorcin and caustic alkali, and also a gazokhromatografichesky research (see Hro-matpografiya).

The expert opinion on Ch.'s poisoning at. as to a cause of death is based on cumulative assessment of results of a research of a corpse, judicial and chemical and histologic researches.

See also Solvents.

Bibliography: Careful R. V. of SU

debno-medical examination of poisonings with technical liquids, page 104, M.,

1977; Harmful substances in the industry, under the editorship of N. V. Lazarev and E. N. Levina, t. 1, page 198, L., 1976; Acute management at acute poisonings, under the editorship of

S. N. Golikov, page 99, 210, M., 1977; The Guide to forensic medical examination of poisonings, under the editorship of R. V. Berezhny p other, page 341, M., 1980; With and N about c -

to and y I. V. and Ulanov I. P. Criteria of harm in hygiene and toxicology at assessment of danger of chemical compounds, page 162, M., 1975; Shvayko-

in and M. D. Toxicological chemistry, page 78, M., 1975.

A. F. Rubtsov (court.), A. I. Tochilkin (biochemical), And. II. Ulanova (gigabyte.).