ALKALIS

From Big Medical Encyclopedia

ALKALIS — the general name of the strong water-soluble bases. In medicine Shch. apply as the irritating, cauterizing, disinfecting and antiseptic agents. Calcium hydroxide — hydrated lime (see Lime) in the form of water solutions (a calcareous water, Aqua calcarea) is applied to neutralization to - t.

Hydroxides of alkali metals (see) NaOH, the GAME called by usually caustic alkalis first of all belong to alkalis (see. Caustic soda, Caustic heat). Properties of alkalis also hydroxides of alkaline earth metals (see) — Sa (IT) 2, Wa (IT) 2, and also NH4OH ammonium hydroxide (see Ammonia), water solutions of aliphatic amines (see) and a hydrazine (see), tetraalkyl ammonium hydroxides possess. Chemical action, similar to alkalis, alkaline salts weak to - t (see Acids and the bases) — carbonates (soda, potash), pyroborates (e.g., Na2B407), trisubstituted phosphates (e.g., Na3P04), etc. possess. Properties caustic Shch. show water r-ry alcoholates of alkali metals (see Alcohols). In water solutions caustic Shch. almost completely dissociate (see Dissociation in chemistry) on ions of alkali metal and a hydroxyl (IT ~) thanks to what they are the strongest bases, same the high basicity of tetraalkyl ammonium hydroxides which is not conceding caustic Shch is caused. Smaller basicity of alkaline-earth hydroxides and NH4OH ammonium hydroxide is connected with smaller extent of their dissociation. Alkaline properties of pseudosalts to - t have a talk their hydrolysis with formation of caustic alkalis: Na2C03 + H20 of NaHCOo-f-+ NaOH.

Y. — hydroxides of alkali and alkaline earth metals — colourless crystal substances, they are hygroscopic, especially caustic alkalis spreading on air. All alkalis vigorously absorb carbon dioxide (C02 carbon dioxide gas) from air, turning into carbonates therefore they are stored bottletight. Caustic Shch. (except LiOH lithium hydroxide) well rastvorima in water (to 50% and above), and also in methyl and ethyl alcohols. Hydroxides of alkaline earth metals of a rastvorima in water it is moderate, their solubility increases from Sa (IT) 2 to Wa (IT) 2. Dissolution Shch. in water happens to considerable calorification owing to formation of hydrates (see Hydration). Solutions Shch. have the pH values (see. Hydrogen ion exponent) equal about 11 — 14, and sharply change coloring of acid-base indicators (see). At interaction with acids Shch. form salts (see) that is widely used in practice not only for neutralization to - t but also as an analytical method (see Neutralizations a method). During the processing their saponification (see) therefore salts of fatty acids — soaps are formed (see) happens alkali of fats (see). Caustic Shch. have big chemical activity and react with many substances and materials. Nek-ry metals — aluminum, zinc, tin, etc. — react with solutions caustic Shch., napr, aluminum korrodirutsya even weak Shch. (soda, ammonia). In the concentrated solutions and especially in flux caustic Shch. destroy glass, porcelain and even platinum (in the presence of oxidizers, including air) that should be considered during the work with melted Shch. (in these cases use ware from iron, nickel or silver). Caustic Shch. corrode and destroy animal and vegetable fabrics owing to hydrolytic action on proteins, however vegetable fabrics are exposed to such action Shch. to a lesser extent.

Use of alkalis in disinfection is based on their properties to hydrolyze proteins, to saponify fats, to split carbohydrates, to destroy a microbic cell (see Disinfection, Desinfectants).

From Shch. the most active is caustic soda, or the caustic soda (NaOH), to-ry possesses bactericidal, virulitsidny, and in high concentration at an elevated temperature — sporotsidny action; its 2 — 4% solutions apply at intestinal and droplet infections of a bacterial and virus etiology, and 10% the solution heated to 75 ° — at a malignant anthrax. These solutions disinfect premises of catering establishments, sheepskin and fur-coat plants, warehouse for raw materials of animal origin, and also Rooms for animals.

Sodium metasilicate (mix Na20 and Si02) possesses bactericidal, bleaching and detergency; it is applied restrictedly to disinfection at intestinal and droplet infections of a bacterial etiology since 2% solution of sodium metasilicate spoil paint, rubber gloves, decolours fabrics, on glasses leaves indelible spots. Sodium carbonate (soda) possesses weak bactericidal action, its 1 — 2% use solutions as subsidiary means at boiling for the purpose of disinfecting of ware, linen, objects of patient care, and also for wet and mechanical cleaning of rooms, cleaning of the equipment, furniture.

NH4OII ammonium hydroxide (see Ammonia) has weak bactericidal properties and is used generally for neutralization of formaldehyde after processing of various objects by it.

SAO quicklime is applied to disinfecting of surfaces by their whitewashing at the rate of

1 l of 10% of water solution (lime milk) on 1 zh2, and also to processing of allocations and the soil.

Alkalis as professional harm. Alkalis apply in the textile, paper, tanning industry, soap manufacture, etc. They can get into a human body with inhaled air or through a mouth (at accidental or intentional intake). Y. have the sharp irritating and cauterizing effect on skin and mucous membranes. Caustic alkalis are deeper, than acids (see. Sulphuric acid, Hydrochloric acid), get into fabrics, dehydrate them, saponify fats, form alkaline albuminates with proteins, causing a kollikvatsi-onny necrosis. Weight of defeat depends on concentration and temperature of solution Shch., sizes its pH. At hit on skin Shch. cause burns (see), healing to-rykh proceeds is longer, than in case of influence of acids since the located fabrics are involved in process more deeply. All-toxic action shch. it is expressed poorly and it is shown preferential in cases hron. courses of poisoning.

At constant contact Shch. with skin development of nodular dermatitis (see), emergence painful is possible, it is long not healing sores (like «bird's eyes»), eczemas (see). Skin becomes dry, between fingers cracks are formed, nails become thinner, break, deformed, separate from a nail bed. The termination of contact with Shch. leads to bystry recovery.

At hron. influence of dust or aerosol Shch. on respiratory tracts can develop hron. rhinitises (see), pharyngitises (see), bronchitis (see), emphysema of lungs (see). As a result of swallowing dust or particles of an aerosol there are gastritises (see), in some cases cankers of a mucous membrane of a stomach can be observed.

At acute poisoning with aerosols or dust Shch. in high concentration, got into airways with inhaled air, there is a sharp irritation of a mucous membrane of upper respiratory tracts, the tracheobronchitis develops. At acute peroral poisoning of units. there is a burn of an oral cavity, a gullet, stomach, painful vomiting, a diarrhea with blood, strong thirst, an ischuria, later — develops a toxic nephrosis, pneumonia, a purulent mediastinitis, an empyema of a pleura, heart failure up to a collapse and shock. Sometimes note a laryngospasm, hypostasis of a throat and lungs, psychomotor excitement (especially at poisoning with ammonium hydroxide). Quite often there is a perforation of a wall of a stomach, sometimes note the esophageal and gastric difficult stopped bleedings, peritonitis and (without timely prevention) formation of stenoses of a gullet, cardial and peloric departments of a stomach of more extensive, than at poisoning with acids.

At hit of units. in eyes there is an acute irritation of a conjunctiva, opacification and a keratohelcosis, damages of deeper layers of an eye — an iris, a vitreous and a retina, the blindness can be a consequence of what.

First aid and N e about t - false therapy at hit Shch. on skin consists in immediate washing off Shch. a water jet within 5 — 10 min. then put lotions from 5% of solution on the struck place lemon, tartaric or acetic to - t. If Shch. got into eyes, they are immediately washed out a plentiful water jet within 10 — 30 min., at hit in eyes of calcium hydroxide of an eye wash out 5% solution of ammonium muriate or 0,01% solution of a tetatsin of calcium then dig in 0,5% solution of Dicainum or 1% solution of novocaine.

At acute inhalation poisoning Shch. the nasopharynx is washed out water with divorced in it lemon to - that, the victim allow to breathe oxygen with the acidified water vapor, inside appoint codeine, at indications — cardiacs. At peroral poisoning Shch. carrying out all complex of the urgent actions applied at poisonings (see) is necessary i.e. a gastric lavage the cold acidified water via the probe oiled vegetable before washing subcutaneously enter 1% of solution of morphine and 0,1% of solution of atropine on 1 ml. Hold events for treatment of burn shock (see) — Polyglucinum, a glyukozonovokainov I am mix intravenously kanelno; subcutaneously enter 2 ml of 2% r ~ ra a papaverine, 1 ml of 0,2% of a pla-tifidlin, 1 ml of 0.1% of solution of atropine (to 6 — 8 times a day). At development of bleeding — a local hypothermia of a stomach. The victim should provide rest, heat, in hard cases urgent hospitalization is required. Further treatment, as well as at hron. intoxications of HZ., symptomatic.

ALKALINE EARTH METALS 511


Examination of working capacity. Questions of examination of working capacity, medical and labor rehabilitation at intoxications Shch. decide taking into account expressiveness a wedge, symptoms of intoxication and a gigabyte. characteristics of working conditions.

G1 r about f and l and to t and h e with to and e m e-ropriyatiya during the work with Shch. provide sealing of loading and unloading of HZ., continuity of a techno of l. process; the equipment shall be supplied with shelters with the local exhaust ventilation (see). Under special control there have to be raising dust processes (crushing, transportation, etc.), and also work with hot solutions Shch. Workers shall be provided with safety spectacles (see), respirators (see), overalls (see Clothes special) and gloves. Medical examinations are periodically carried out (see. Medical examination).

Maximum allowable concentration in air of a working zone is established for caustic alkalis (in terms of caustic soda) 0.5 mg/m3, for calcium carbonate (limestone) — 6 mg/m3, sodium carbonate (the soda calcinated) — 2 mg/m3.

Alkalis in the medicolegal relation. Poisonings Shch. are rather rare, arise generally at peroral receipt in an organism as a result of accident or with the suicide purpose of ammonium hydroxide, caustic soda (caustic soda), caustic heat, extinguished [Sa (IT) 2] and not extinguished (SAO) of lime. A lethal dose at poisonings Shch. makes 10 — 20 g, and the lethality reaches 50%. Death can come as in the next few hours after hit Shch. in an organism from ekzotoksiches-whom shock, a toxicogenic collapse. acute respiratory insufficiency (due to oppression of function of a respiratory center, a laryngospasm. a toxic fluid lungs), and later — - from cardiovascular insufficiency or complications: pneumonia, purulent mediastinitis. empyemas of a pleura, toxic nephrosis, etc. At court. - a medical research of a corpse note a characteristic deep friable (stake-likvatsionny) necrosis of a wall of a stomach (especially at poisoning caustic heat) without clear boundary with the unimpaired fabric. The wall of a stomach soapy to the touch, is covered with a scab gray or greenish-brown (due to formation of alkaline hematin! colors. Serous covers and in fabric note also hypostasis of a mucous membrane of a throat, throat, inflammatory changes of a mucous membrane of a trachea and bronchial tubes, hypostasis and emphysema of lungs, hypostasis of substance and a plethora of vessels of a brain, a plethora of internals, dot hemorrhages iod. Reveal hypostasis, a plethora, hemorrhages and a necrosis of a mucous membrane and a podelizisty layer of a gullet and stomach, infiltration of their wall leukocytes, proteinaceous dystrophy of parenchymatous bodies with hypostasis of interstitial fabric, fibrinferments of small vessels.

At court. - a chemical research Shch. allocate from biol. material by dialysis. At alkali reaction to dialyzate add spirit of phenolphthalein and excess of barium chloride. Preservation by dialyzate of pink coloring demonstrates existence in it Shch. The chemical nature of a cation (Na+, K+,

Sa2+) is established a characteristic crystal deposit by training at addition to dialyzate of sodium pyroantimoniate, tartaric to - you and ammonium oxalate; at negative test on hydrogen sulfide determine ions of NH by a posineniye of a red litmus paper. In a basis kolichestven-

the 4th

leg of definition Shch. titration of an aqueous extract from the studied fabric to - that in the presence of the indicator lies (see Titri the metric analysis).

In a task court. - medical examinations at survey of the victims establishment of severity of the injuries caused by action Shch can enter., and at a research of corpses — establishment of poisoning Shch. as causes of death. Assessment of severity of injuries in these cases is carried out by a usual order (see Damages to the medicolegal relation); diagnosis of poisoning Shch. as causes of death it is made on the basis of assessment anamnestic and a wedge, yielded, results of necropsy, with ud. - chemical and with ud. - gistol. researches.

Bibliography: Avdeev M. I. Judicial

medical examination of a corpse, page 367, M., 1976; In and sh to about in V. I. Guide to disinfection, disinsection and deratization, page 96, M., 1956; it, Antimicrobic cure and methods of disinfection for infectious diseases, page 33, M., 1977; Harmful substances in the industry, under the editorship of N. V. Lazarev and I. D. Gadaskina, t. 3, page 320, L., 1977;

3 and about r and AA. Industrial ophthalmology, the lane with polsk., page 111, etc., M., 1961; Nekrasov B. V. Fundamentals of the general chemistry, t. 2, page 213, etc., M., 1973; The Guide to forensic medical examination of poisonings, under the editorship of R. V. Berezhny, etc., page 79, M., 1980; Forensic medicine, under the editorship of A. R. Denkovsky and A. A. Matyshev, page 229, L., 1976.

And. I. Tochilkin; I. V. Buromsky (court.), E. N. Marchenko (gigabyte.), N. F. Sokolova

(epid.).

Яндекс.Метрика