Caustic Alkalis

Caustic Alkalis, water-soluble hydroxides of metals: potassium hydroxide, caustic potash, KON; sodium hydroxide, caustic soda, NaOH, used in technology in impure form under the name of caustic soda; calcium hydroxide, slaked lime, Ca(OH)₂ (slaked lime, hydrate of calcium oxide CaO); barium hydroxide, caustic baryta, Ba(OH)₂ (hydrate of baryta, oxide of barium BaO). The term Caustic Alk. applies to both solid substances and their solutions ("lye"). Ammonia solution is also included among Caustic Alk. as containing ammonium hydroxide (hydrate of ammonia): NH₃+H₂O:NH₄OH, analogous to potassium hydroxide, sodium hydroxide, etc. In aqueous solutions, all of them show an "alkaline" reaction to litmus (red litmus turns blue) and other indicators, which is due to the formation of the common hydroxyl ion OH (see Electrolytic dissociation): e.g., KON?K"+ OH'. An "alkaline" reaction besides Caustic Alk. may be caused by salts of "weak" acids (carbonic, silicic, boric, cyanic, etc.) due to the decomposition of these salts by water (hydrolysis), e.g.: K₂CO₃+ + H₂O^KHCO₃+KON. To distinguish caustic alkalis from carbonate alkalis (carbonate salts), a few drops of an alcoholic solution of phenolphthalein are added to the solution, then an excess of barium chloride (BaCl₂); the resulting pink or red color in the solution of Caustic Alk. remains, while in the case of carbonate salts it disappears due to the precipitation of insoluble barium carbonate (K₂CO₃+BaCl₂=BaCO₃+2KCl) with the destruction of the soluble carbonate salt, the hydrolysis of which causes the appearance of hydroxyl ions (alkaline reaction). The effect of Caustic Alk. on the organism is due to the removal of water from tissues, dissolution and destruction of protein bodies, during which alkaline albuminates are formed in the form of a gelatinous swollen mass. Aqueous oxides of alkali metals penetrate deeply into tissues, causing extensive destruction; for this reason, Caustic Alk. are classified as cauterizing agents and are used externally for therapeutic purposes when deep and extensive destruction of tissues is needed to prevent general poisoning (e.g.: in bites of snakes or rabid animals, in wounds during work with corpses, etc.). The effect of Caustic Alk. on protein also determines the disinfecting action of these substances. Caustic Alk. dissolve well mucous, emulsify fats, dissolve hair, feathers, and keratinized epithelium, and solutions of lower concentrations of caustic alkalis soften the superficial layers of the epidermis and for this purpose can be used in the form of general or local baths for certain skin diseases. Concentrated or slightly diluted caustic alkalis burn and destroy all mucous membranes of the mouth, esophagus, and stomach; the mucous membranes at first become cloudy, whitish, and later swell, acquiring a translucent jelly-like appearance; such changes are especially strongly expressed in the stomach (bottom and exit), where in addition a brown discoloration of the affected parts may be observed due to the destruction of blood and imbibition of tissues with blood pigment. If the patient survives the acute period of poisoning, then later the dead parts of the mucous membrane are rejected, due to which ulcers form, which later scar. The resulting scars can cause narrowing of the esophagus, stomach. Poisoning with alkalis occurs less frequently than with acids: in most cases in suicide (with ammonia alcohol, sometimes in the form of epidemics), less frequently in accidents and even less frequently in murder; according to the latest forensic medical statistics, fatal cases reach about 2% of all poisonings; non-fatal poisonings are much more numerous. After taking alkali internally, vomiting immediately appears with brown masses mixed with gelatinous films, severe pains are felt throughout the gastrointestinal tract, soon diarrhea sets in, often bloody; blood turns into a brown gelatinous mass due to the formation of alkali. hematine; urination is delayed, urine becomes alkaline, contains protein and precipitating phosphates. Death can occur very quickly, sometimes poisoning lasts for 2-3 days; with potassium compounds, general weakness and paralysis of the heart appear. The lethal dose is difficult to determine (Kobert), but is approximately equal to 20 cm* 15% solution of caustic potash (Kosorotov). As antidotes in poisoning with Caustic Alk., 1% solutions of citric, tartaric, acetic, or hydrochloric acids are administered internally, mucous drink with the addition of the same acids, milk, protein water, oil emulsion, ice pieces; for external burns - compresses from 5% solutions of the above acids and baths from acidified water. In terms of the number of poisonings, first place is occupied by poisoning with caustic soda (sodium alkali), which is most readily available in everyday life. Burns from calcium oxide (CaO) are caused, besides the removal of water, also by an increase in temperature accompanying the hydration process: CaO+H₂O=Ca(OH)₂. In the production of caustic soda (sodium hydroxide), cases of burns among workers are frequent (according to Navrotsky up to 70%), especially eye burns. Masons and other workers dealing with lime often suffer from diseases of the skin, respiratory organs or eyes due to the ingress of lime dust into these parts of the body (Hamilton, Sigrist). Of the preparations of Caustic Alk., the following are most commonly used for therapeutic purposes: Ammonium causticum solutum (Ph. VII), s. Solutio, s. Liquor Ammonii caustici- ammonia alcohol, sp. gr. 0.959 - 0.960; contains 9.9-10% NH₃; a colorless volatile liquid with a sharp smell of ammonia gas and strongly alkaline reaction; mixes with water and alcohol in any proportions. (Pharmacological properties and therapeutic application-see Ammonia.)-Ammonium causticum spirituosum (Ph. VII), s. Liquor Ammonii caustici spirituosus - a colorless transparent flammable liquid, sp. gr. 0.808 - 0.810 with the smell of ammonia. Action and application, as the previous preparation.-Kalium hydro oxydatum fusum (Ph. VII)-fused caustic potash or Kali causticum fusum - hydrate of potassium hydroxide; white translucent, in fracture crystalline pieces or cylindrical sticks, containing not less than 84.7% caustic potash, easily attracting water and carbon dioxide from the air and easily soluble in water and alcohol; therapeutically used externally 1) in substantia in the form of the so-called Filgovsky pencil for cauterization or lapis causticus chirurgorum, when deep action is needed (e.g.: in bites of rabid or poisonous animals, for the destruction of voluminous and dense condylomas and warts, lupus nodes and infiltrates); 2) in solutions for local baths 2.0-4.0 per 1 liter of water and for general baths 30.0-100.0 per bath in 200 liters of water; 3) in 1-5% solution for injections into the ear in purulent otitis; 4) in 0.1% solutions for washing the skin and in 0.5-1% solutions for washing torpid and fungoid ulcers: 5) in pastes, popular pasta caustica viennensis- caustic Vienna paste, or caustic Vienna dough, a mixture of 3 parts caustic potash with 1 or 3 parts calcium oxide (CaO- Calcaria usta) forms a powder used as a powder or with the addition of a few drops of alcohol turned into a dough-like mass-paste.-Kalium bydro-oxydatum solutum (Ph. VII), s. Kali causticum solutum, s. Liquor Potassae, a solution of 35 parts of fused caustic potash in 165 parts of water; a clear colorless liquid, strongly alkaline reaction; sp. gr. 1.128-1.132; contains about 15% aqueous potassium hydroxide; in the form of inhalations with a large amount of water-in catarrhs of the respiratory tract for dissolving mucus; externally used in most cases as Kalium causticum fusum and also in the form of liquid liniments (linimenta) in eczema and other chronic diseases of the skin.-Liquor Natrii caustici, a 15% aqueous solution of sodium hydrate; action and therapeutic application-as the corresponding potassium preparation.-Calcium hydro-oxydatum solutum (Ph. VII), solution of slaked lime, s. Calcaria caustica soluta, s. Aqua Calcariae, s. Aqua Calcis, lime water, solution of calcium hydrate; a colorless, transparent liquid, alkaline taste, strongly alkaline reaction; contains 0.15--0.17% slaked lime Ca(OH)₂; on the air and when boiling it becomes cloudy, due to the formation of insoluble calcium carbonate; internally it was used as an astringent and acid-neutralizing agent in gastrointestinal catarrhs 50.0-150.0 per dose, 4-6-8 times a day, in pure form; in pyelitis and cystitis with milk, broth or vegetable juice; also in rickets; in enemas per se or with the addition of oatmeal mucilage in dysentery or ulcers of the rectum and colon; externally-in the form of gargles, lubrications and atomization in diphtheria for dissolving films and plaques, in syphilitic ulcers in the mouth; as an astringent in eczema and burns; in the form of lime liquid liniment (Ph. VII)--Linimentum Calcis, s. Lin. calcarium (a rather thick yellowish-white ointment, prepared ex tempore from equal parts Aq. Calcis and 01.

Lime—for compresses in burns and ulcers.—Soda lime—a calcined mixture of caustic soda and caustic lime—is used in chemical analyses for the absorption of carbon dioxide, and sometimes also of water, and in gas masks—for the absorption of hydrogen chloride, as a product of the hydrolytic cleavage of phosgene, in the fight against chloropicrin and hydrogen cyanide. In technology, unslaked lime is used for dehydrating alcohol; slaked lime with water (milk of lime) and limewater serve as reagents; with caustic potash, Spiritus saponatus (Ph. V^TT) and "green" soap, Sa-po viridis (Ph. VII), are prepared, and with caustic soda—all other kinds of soap; solutions of caustic potash and soda (15%) are used as reagents in chemical and biochemical practice.. Discovery of E. щ. in forensic-chemical research and in protection from professional poisonings. Investigation for E. щ. is carried out in the presence of a strongly alkaline reaction of the stomach contents or its mucous membrane or the mucous membrane of the esophagus. The internal organs (stomach, esophagus) are minced and, together with the stomach contents, are extracted with distilled water. The extract is quickly filtered. To a part of it, a few drops of an alcoholic solution of phenolphthalein and an excess of barium chloride are added. In the presence of caustic alkalis, the red or pink color is preserved. After adding barium chloride, the extract in a measuring flask is diluted to the mark with distilled water (freed from carbon acid by boiling), allowed to stand, and a certain portion of the liquid is titrated with ⁿ/₁₀ acid solution. In the same way, vomit is examined when it has an alkaline reaction (in the fresh state).-To determine the amount of E. щ. (mainly unslaked lime), weighed as dust in the air, a certain volume of the latter is drawn through a series of flasks with a titrated acid solution (ⁿ/₁₀) at such a speed that the bubbles can be counted. Methyl orange is added to the acid as an indicator. After the passage is completed, the liquids from the washing flasks are combined, and the excess acid is titrated with ⁿ/₁₀ alkali solution. The drop in acid titration corresponds to the amount of alkali absorbed as dust from the air (e.g. CaO).