ACETALDEHYDE (acetic aldehyde, ethanal) — aliphatic aldehyde, CH3CHO; the metabolite which is formed at spirit fermentation, oxidation of alcohol including in a human body, and in other exchange reactions. At. and. use during the receiving various pharmaceuticals (see), acetic acid (see), peroxyacetic to - you SNDSOOON, acetic anhydride (CH3C0)20, ethyl acetate, and also in production of synthetic resins, etc. On the corresponding productions represents professional harm.
At. and. represents a colorless liquid with a pungent smell, / °pl — 123,5 °, * °kip 20,2 °, its relative density at 20 ° [d] * °
0,783, index of refraction at 20 ° [p]2^ 1,3316, concentration
these limits of explosibility (KPV) of 3,97 — 57%. With water, alcohol, ether and other organic solvents U. and. mixes up in any ratios.
At. and. enters all reactions characteristic of aldehydes (see), in particular it is oxidized to acetic to - you, undergoes aldol and crotonic condensation, forms acetum-ethyl ether on Tyshchenko's reactions and derivatives, characteristic of aldehydes, on carbonyl group. In the presence of acids U. and. it will be polymerized to cyclic crystal tetramer of metaldehyde or liquid paraldehyde. In a commercial scale At. and. receive hydration of acetylene (see) in the presence of catalysts — mercury salts, oxidation of alcohol (see) and the most economic way — oxidation of ethylene (see Hydrocarbons) in the presence of the palladic catalyst.
High-quality detection At. and. it is based on emergence of blue coloring in резз^льтате interactions At. ampere-second Sodium nitroprussidum in the presence of amines. Quantitative definition consists in receiving any derivative At. and. on carbonyl group and its weight, volume (see. The titrimetric analysis) or colorimetric definition (see Colorimetry).
Education At. and. as intermediate product of a metabolism occurs both in vegetable, and in animal organisms. The first stage of transformation of alcohol in a human body and animals is its oxidation to At. and. in the presence of alcohol dehydrogenase (see). At. and. it is formed also at decarboxylation (see) pyruvate (see. Pyruvic acid) at spirit fermentation and during the splitting of threonine (see) under action threonine-zymohexase (KF 18.104.22.168). In a human body At. and. is oxidized to acetic to - you are hl. obr. in a liver under action OVER - dependent aldehyde oxidase (KF 1.2.3. 1), atsetaldegidooksidaza and ksantokinaza. At. and. participates in biosynthesis of threonine from glycine (see). In narkol. to practice use those that a frame (see) it is based on ability of this drug to specifically block acetic aldehyde oxidase that leads to accumulation in blood U. and. and, as a result, to strong vegetative reaction — expansion of peripheral vessels, heartbeat, a headache, suffocation, nausea.
Acetaldehyde as professional harm. At hron. impact on the person of low concentration of vapors U. and. note passing irritation of mucous membranes of upper respiratory tracts and a conjunctiva. Couples At. and. in inhaled air in high concentration cause increase
of pulse, the increased perspiration; signs of sharp irritant action of vapors U. and. in these cases amplify (especially at night) and
can be combined with suffocation, dry painful cough,
a headache. Bronchitis and a pneumo
niya happen an effect of such poisoning.
Hit on skin liquid At. and. can cause its hyperemia and emergence of infiltrates.
First aid and emergency treatment. At poisoning with couples At. and. the victim needs to be brought to fresh air, to provide inhalation of water vapor with spirit of ammonia, at indications — inhalations of the moistened oxygen, cardiacs, stimulators of breath (lobeline, cytotone), Tinctura Valerianae, drugs of bromine. At sharp irritation of mucous membranes of respiratory tracts — alkaline or oil inhalations. At painful cough — codeine, ethyl morphine a hydrochloride (dionine), mustard plasters, banks. At irritation of a conjunctiva — plentiful washing of eyes water or isotonic solution of sodium chloride. At poisoning through a mouth — an immediate gastric lavage water with addition of solution of ammonia (spirit of ammonia), 3% solution of hydrosodium carbonate. Further treatment — symptomatic. At hit At. and. on skin — immediate washing of an affected area water, but is better than 5% solution of spirit of ammonia.
The victim shall be discharged of work with harmful substances before recovery (see. Occupational diseases).
Measures of prevention of intoxications At. and. consist in sealing of the equipment, no-failure operation of ventilation (see), mechanization and automation of works on pouring and transportation At. and. To store At. and. it is necessary in hermetically the corked vessels. On productions and in the laboratories connected with contact with At. and., measures of personal hygiene, use of special clothes and footwear, safety spectacles, universal respirators shall be observed strictly.
COCHLEAR TUBULE 41
Maximum allowable concentration of vapors U. and. in air of a working zone of 5 mg/m3.
Bibliography: Harmful substances in the industry, under the editorship of N. V. Lazarev and E. N. Levina, t. 1, L., 1976; Loeb
of N. N. Himiya's maidens and technology of the main organic and petrochemical processing, M., 1981; Whyte A. and d river. Fundamentals of biochemistry, the lane with English, t. 1 — 3, M., 1981, A. N. Klimov, D. V. Ioffe;
N. G. Budkovskaya (gigabyte.).,