HYDROCARBONS

From Big Medical Encyclopedia

HYDROCARBONS — organic compounds, molecules to-rykh are constructed of two elements — carbon and hydrogen. Hydrocarbon chains make a basis of many natural compounds: vitamins (see), fatty acids (see), lipids (see), antibiotics (see), carotinoids (see), natural dyes (see), etc.; in a human body and animals At., especially fats (see), are a main type of reserve nutrients. In medicine many At. are used directly as pharmaceuticals or are a basis for their synthesis. At. in animal organisms often form protective films, at plants At. make a basis of synthesizable polymers, e.g. rubbers (see), are a part of vegetable oils (see Vegetable oils). Many organic compounds (see) represent substitution products At. are also their derivatives. At. make a basis of the majority of combustible minerals and are widely used in the national economy.

How atokhma of carbon (see) in a carbon chain are connected among themselves, At. divide into several types. At. with an open, unbranched or branched saturated carbon chain (At. aliphatic, or fat, a row) call alkanes, or paraffin. The first representatives of a number of unbranched alkanes are methane (see), ethane, propane, butane. Names of the following members of a row consist of the prefix specifying number of carbon atoms (pent-, geks-, gept-etc.), and the termination «~ An» indicating belonging of connection to alkanes; to point to a nerazvet-vlennost of a carbon chain, usually add the N-prefix (normal). The prefix «from-» is used in names of connections, in to-rykh two methyl groups are on the end of a stralght chain, the neo-prefix indicates existence of three methyl groups on the end of a stralght chain. At formation of names of other type U. — branched out — them are considered as a substitution product of simpler At. substituting groups — radicals (methyl, ethyl, butyl, etc.). At., the containing cycles (rings) consisting of the carbon atoms connected among themselves by simple bonds are called cycloalkanes (alicyclic At., cycloparaffins). A rich source of cycloalkanes is oil (see) therefore sometimes they are called naphthenes. Names of cycloalkanes are formed by addition of a prefix «a cycle -» to names of the corresponding alkanes (naira., cyclopro-shares, cyclopentane, cyclohexane., etc.). Cycloalkanes can be mono-cyclic, bicyclic and polycyclic. In the nature connections from five - and six-membered cycles are most eurysynusic.

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HYDROCARBONS U., the containing double bonds, so-called unsaturated At., call alkenes, olefins, or olefinic At. At formation of names of alkenes in the name of the corresponding alkane the termination «-An» is replaced on «-ilen» (e.g., ethylene, propylene, butylene etc.). At., the containing two or more double bonds, call it is scarlet dienes (two double bonds), alkatriyena (three double bonds) etc. Alkynes call At., having in a molecule triple carbon — carbon bonds. The simplest representative of this class U. acetylene is (see). Names of alkynes form of names of alkanes, replacing the terminations «-An» on «-in» (e.g., etin, butene, hexyne etc.). On number of acetylene bonds these At. divide on it is scarlet-kadiiny, alkatriina etc. At., the containing at the same time double and acetylene bonds, call alkeni-us, alkadiyenina etc. according to number of double and acetylene bonds in their molecules.

To cyclic At., containing double bonds — aromatic At., or to arenes, benzene belongs (see). Aromatic call all connections, the molecule to-rykh includes benzene ring therefore the aromatic series of connections is designated also as a number of benzene. To mono-cyclic At. a number of benzene belong toluene (see), xylols (see), etc. Besides, exist ranks aromatic At. with several benzene rings in a molecule. Kernels in them can be connected by simple bonds (biphenyl), through intermediate chains of carbon atoms or the general carbon atoms can have (diphenylmethane) (naphthalene, anthracene, phenanthrene, etc.). At. the last type carry the name of aromatic compounds with the condensed benzene rings. Difficult condensed aromatic At. divide on linear, napr, anthracene, the centers of benzene rings to-rykh lie on one straight line, and angular, napr, phenanthrene (see), benzene rings in their molecules are combined thus that on one straight line the centers only of a part of these kernels lie. The main sources aromatic At. oil (dry distillation, or reforming) and black coals (coking) are.

At. depending on amount of carbon atoms in their chain can be gases (methane, ethane), liquids and solid matters (cetane, an okt the dean, etc.). Among alkanes with each additional CH2-group temperature of boiling increases approximately on 30 °, density and, to a lesser extent, temperature of melting of substances increase. Temperatures of boiling and melting of cycloalkanes are higher, than at the corresponding alkanes. In process of increase in quantity of double bonds in molecules of alkenes or numbers of fused rings at aromatic At. these connections from colourless become painted (carotene, the hexaprices). Alkanes, alkenes, alkynes, cycloalkanes and aromatic At. differ with UF-, infrared ranges and ranges of nuclear magnetic resonance (see).

In total At. on air burn down with formation of water and carbon dioxide gas. From all At. alkanes and cycloalkanes in the chemical relation are most inert. Alkenes and alkynes, on the contrary, have high reactivity and easily enter addition reactions on double and triple bonds. High reactivity also conjugated compounds have (when double bonds alternate with simple bonds between carbon atoms). Alkenes and alkynes are capable to polyreactions (see). Aromatic At. especially easily enter various substitution reactions, than their wide use for various chemical sintez is defined.

Carbon chains At. in an organism of animals and plants are synthesized with participation atsil-KOA (see. Fatty acids, Methyl-aminoacetic acid, Tricarboxylic acids cycle). The majority of aerobic cells is capable to full oxidation of hydrocarbon chains of fats to carbon dioxide gas and water as a result of the processes proceeding in a matrix of mitochondrions of eukaryotic cells.

Hydrocarbons as professional harm. In total At. have narcotic properties; intensity of their narcotic action increases in gomol. ranks to a certain member of a row (the so-called rule of Richardson). At branched out At. force of narcotic action is weakened in proportion to degree of a branching of a carbon chain. The highest alkenes along with narcotic possess convulsive action, besides, they render weak irritant action on respiratory tracts. Alicyclic At. (cycloalkanes) possess stronger action, than corresponding At. fatty series. Alicyclic At. irritate skin and mucous membranes, affect blood and the hemopoietic bodies (especially nonlimiting alicyclic At.).

Narcotic action At. it is caused by their interaction with c. N of page at the level of neuron and interneural synoptic communication. Specific action on blood and the hemopoietic bodies alicyclic At., including aromatic At., first of all, connect with features of their metabolism in an organism and formation of phenols and polyphenols.

The special place among At. from the point of view of professional harm (see. Professional harm) borrow aromatic At. with the condensed benzene rings, many of them have oncogenous properties (see. Oncogenous substances).

Danger of the prof. of poisonings At. it is substantially caused by their volatility. At. a fatty series, the gases representing in normal conditions, can contain in air in any concentration and lead in some cases to a lack of oxygen of mines and excavations and to explosions. Couples limit At. with a carbon chain length of 6 — 9 carbon atoms, the gasolines which are a part (see), white spirit, kerosene, can create considerable concentration in air of production rooms in rubber, paint and varnish, machine-building and other industries. Impact on the person of mixes U. perhaps at oil refining and gas, at synthesis of alcohols and fat to - t, in production of detergents (see) etc., and also during the use of mixes U. in fuel quality, lubricating oils, solvents and at their use for organic synthesis.

Hron. poisonings sated At. are characterized by disturbances from century of N of page. These shifts are most expressed at hron. poisonings with mixes saturated and unsaturated At., and also At. oil, gasolines, lubricating oils, etc. Functional changes from c. the N of page and century of N of page are followed by cardiovascular disturbances, frustration went. - kish. a path, disturbances of functions of a liver, changes from blood (coagulopathy) and defeat of the hemopoietic bodies.

During the processing and receiving oil, and also use of fuel oil, bitumens, the lubricant cooling materials, lubricating oils, etc. chances of damage of skin: a toxic melanosis (see), the prof. dermatitis (see), eczemas (see Eczema), keratoza (see), warty growths (see the Wart), papillomas (see Papilloma, a papillomatosis). Oncogenous action of products of distillation of black coal, oil shales and oil products is caused by presence at them polycyclic At.

Treatment at hron. poisonings symptomatic.

Acute poisonings At. are characterized by nonspecific symptoms, the expressed pallors, a headache, weakness, nausea, vomiting, decrease in the ABP, a loss of consciousness. In some cases, especially at poisoning unsaturated alicyclic At., note strong irritation of mucous membranes, spasms. At poisoning aromatic At. bleeding from mucous membranes, nevrol is characteristic. frustration.

First aid and emergency treatment. The victim needs to be taken out to the warm, well aired room, to exempt from the clothes constraining breath. If toxicant got on skin, it is deleted with warm water with soap. At an apnoea — immediately artificial respiration, urgent delivery in specialized to lay down. establishment. At hit highly toxic At. in a stomach — a gastric lavage of 10 — 15 l of water with the subsequent introduction of 100 — 200 ml of liquid or castor oil. Hospitalization is necessary, at receipt carrying out a hemodialysis is desirable.

In clinic — pathogenetic and symptomatic therapy, special attention needs to be paid to prevention and treatment of ekzotoksi-chesky shock (see). For treatment of a coagulopathy — administration of heparin, for improvement of a hemodynamics and protection of a liver against toxic action At. — Trasylolum (50 000 — 100 000 PIECES a day intravenously). Vitamins of group B, glucose, lipocainum, cocarboxylase, lipoic and glutaminic to - you. Duration of therapy is defined by weight of a state.

Examination trudospo-with about N about with t and. If hron. or acute poisoning At. did not cause a disease, inclined to progressing, the diseased can be temporarily transferred to the work which is not connected with ggrofvrednost. In case of a palindromia or its weighting of the victim discharge of the work which is followed by contact with profvrednost. See also Poisonings, professional;

II rofessionaljny diseases, Examination.

M er p r about f and l and to t and to and poisonings At.: strict gigabyte. rationing (see Standards hygienic ■), replacement toxic At. on safe or less dangerous, improvement of technology, sealing of the equipment, automation of a techno of l. process, local and all-exchange ventilation, observance of measures of individual protection. Necessary preventive measure are preliminary (at revenues to work) and periodic medical examinations (see. Medical examination), and also special food (see Food treatment-and-prophylactic).

Extremely allow m and I am a kontsentra of c and I for aliphatic sated At. with a carbon chain length up to 10 carbon atoms in air of a working zone, in terms of carbon of 300 mg/m3 (a class of danger 4). Maximum allowable concentration separate aliphatic and alicyclic At. in air of a working zone make: amilena (mix of isomers) —

10 mg/m3, 1,3 butadiene — 100 mg/m3, the isoprene — 40 mg/m3, blamed acetylene — 20 mg/m3, cyclohexane — 80 mg/m3, methyl cyclohexane — 50 mg/m3, cyclopentadiene — 5 mg/m3, dicyclopentadiene — 1 mg/m3. Bibliography: Bruyevich T. S. Blasto-

mogennost of products of oil refining, M., 1980; Harmful substances in the industry, under the editorship of N. V. Lazarev and E. N. Levina, t. 1, page 9, L., 1976; Lublin E. I., Minkin N. A. and P y-l about in and M. L. Adaptation to industrial poisons as phase of intoxication, L., 1971; Metsler D. Biochemistry, the lane with English, t. 1, page 80, etc., M., 1980; R about -

e r t with D. and To and with e r and about M. Fundamentals of organic chemistry, the lane with English, t. 1, page 248, t. 2, page 310, M., 1978; With and N about the Central Committee and y And. Century and Ulanova I. P. Criteria of harm in hygiene and toxicology at assessment of danger of chemical compounds, M., 1975; The Reference book on professional pathology, under the editorship of L. N. Gratsianskaya and V. E. Kovshilo, L., 1981.

And. II. Ulanova (gigabyte.), N. V. Prokazova

(biochemical).

Яндекс.Метрика