Methane (marsh gas; CH4) is the simplest unsaturated hydrocarbon. A colorless, odorless gas, temperature melting -182,48 degrees. Methane is easy lights up; the mixture of methane with air explosive.
Methane is the primary component of natural gas (60-99%), methane (35-40%), as well as different products of anaerobic decomposition of organic substances, such as marsh gas, gas irrigated fields. Large quantities of methane is generated during coking coal hydrogenation of coal and other industrial industries.
Methane used as fuel at gas supply, as well as for industrial synthesis of hydrocarbons large mol. the weight. During incomplete combustion or catalytic oxidation of methane produces methanol (see Methyl alcohol), formaldehyde (see), acetylene (see). Methane is also used in the production of carbon black, methyl chloride, hlorpromazina, nitromethane, hydrocyanic acid and other products.
Methane is found in the intestinal gases (methane fermentation), in the blood of animals and humans.
Methane is the most inert connection from a group of paraffin hydrocarbons. Physiological methane indifferent and can cause poisoning only at very high concentrations (because of the low solubility of methane in the water and the blood). However, the toxic effect of methane is shown and at a lower concentrations of methane in the air. So, when the content in the air 25-30% methane see first signs of asphyxia (increased heart rate, increase in the volume of breath, loss of coordination thin muscular movements, and so on). Higher concentration of methane in the air, causes headache. Fully toxic effect of methane is seen only at high pressure (2-3 ATM).
First aid at acute poisoning: remove victim from a hazardous atmosphere. Heating pad. If not breathing, immediately (before the arrival of the doctor) artificial respiration, which terminated only after the appearance of signs of rigor Mortis.
Chronic effects of methane. From working in mines or factories where the air contains methane and other hydrocarbons number of methane described noticeable changes of the vegetative nervous system (positive oculo-heart reflex, pronounced tropinova test, hypotension). However, the chronic effects of methane does not cause severe organic changes, although some researchers have attributed the emergence of miners ' nystagmus with long lasting effects of methane.
Prevention of poisoning methane. In underground openings are not allowed methane content higher than 0.75%. With the increase in methane workers must necessarily be removed, and the space is ventilated. The main measure to prevent accumulations of methane in mines is the availability of good ventilation. When individual protection requires the use of helmets with forced air supply or breathing apparatus, provided with supply air.
Cm. also Poisoning, Hydrocarbons.