Alkalies, caustic volatile

Explain the terms volatile alkali, caustic alkali, and fixed... 

Most aromatic acid chlorides impart a strongly acid reaction when shaken with water (compare Section 111,88). All are completely hydrolysed by boiling with solutions of caustic alkalis and yield no product volatile from the alkaline solution (compare Eaters, Sections 111,106 and IV, 183). They may be distinguished from acids by their facile reactions with alcohols (compare Section 111,27), phenols (compare Section IV,114), and amines (compare Sections 111,123 and IV.lOO). 

After the furfurel has all been added and the reaction has subsided, the residue is cooled, diluted with water, made strongly alkaline and distilled until all volatile substances are removed. The distillate is then made acid with formic acid and distilled with steam as long as nonbasic substances are carried over by the steam. The residue is then made strongly basic with caustic soda and the volatile amines again distilled with steem. The distillate is then treated with strong alkali and then extracted with ether to extract the base. The extract is dried by the addition of caustic potash, the ether removed and the residual amine purified by distillation. Furfuryl dimethyl amine boils over the range 145°C to 150°C. 

Toxicity Variable. The hydrides of phosphorus, arsenic, sulfur, selenium, tellurium and boron which are highly toxic, produce local irritation and destroy red blood cells. They are particularly dangerous because of their volatility and ease of entry into the body. The hydrides of the alkali metals, alkaline earths, aluminum, zirconium and titanium react with moisture to evolve hydrogen and leave behind the hydroxide of the metallic element. This hydroxide is usually caustic. See also sodium hydroxide... 

OB to C02 —11.7% very volatile, toxic liquid with irritating odor sp gr 1.468 at 18°, mp — not given, bp 120—122° at 17mm and 103° at 15mm decomp at 185° with evoln of brown fumes and chars at 260° sol in w distills with vapors of w ale being si acidic, it dissolves in cold caustic alkali solns, giving a yellow color. It was first prepd in 1920 by Wieland Sakellarios (Refs 1 3) from the same kind of oil as was obtd by Kekule in 1869 (Refs 1 2) on passing ethylene into a mixture of coned nitric and sulfuric acid. 

Bergman explains why he prefers the term air acid or aerial acid to the then usual name—fixed air. In the first place, because this is only one of several kinds of air which occur fixed, and in the second place, because it is at the same time a true acid and a constant constituent of the atmosphere. Fixed air, he says, is a true acid, because it possesses a distinctly acid taste it reddens litmus ( turnsol ) it attacks caustic fixed alkalies, rendering them mild a smaller quantity of this acid than of the stronger acids saturates these alkalies and renders them crystallizable and less soluble it makes the volatile alkali (ammonia) more fixed, less odorous and penetrating and causes it to crystallize when it just saturates quicklime, it deprives it of its solubility and acrimony and causes... 

When volatile acid or alkali is present, this is neutralised exactly with dilute caustic alkali or sulphuric acid, the subsequent procedure being as described above. 

The volatile oils which contain phenols, when shaken with caustic soda or potash solution, diminish in volume owing to the ready solubility of the phenols in alkali. Acidification of this alkaline solution results in the separation of the phenol, which is recognisable by its odour and by the greenish-blue or reddish coloration it gives with ferric chloride. 

The nature of a chemical will, obviously, affect its disposition and its effects on the body (the nature of a chemical can be described in terms of its so-called physico-chemical characteristics). These various characteristics wiU affect both the site of exposure and the consequences of the exposure. A chemical may be a solid, a liquid, or a gas. A solid may be in solution in water, for example sugar in a cup of tea, or in another solvent, for example alcohol, which is used to dissolve the fragrances in perfume. Liquids may be volatile such as petrol or white spirit. A solid may be in the form of lumps, crystals (for example, salt), or very small particles. Furthermore, the chemical could be irritant or corrosive, such as an acid like battery acid (hydrochloric acid) or kettle descaler (formic acid), or an alkali like caustic soda (sodium hydroxide), which is found in oven cleaners. The latter may not be weU absorbed from any of the three sites of exposure but will stiU cause damage to the tissues with which they come into contact. Substances that are not at all soluble in fat wiU not be well absorbed, nor wiU substances that are very soluble in fat but not soluble in water. However, sufficient of the chemical may be absorbed for it to be toxic even if it is a very small amount. Substances that are soluble in fat wiU also be more readily distributed around the body and metabolized. 

Since, in the cases mentioned, hydrochloric acid is always present in excess, and the amines unite with it to form soluble salts, the end of the operation occurs when no more of the insoluble nitro-compound is present, and the reaction-mixture dissolves clear in water. In order to get the free amine from the add mixture, various methods may be employed. If, as in the above example, the amine is volatile with Steam, and insoluble in alkali, then the acid solution is treated with caustic potash, or caustic soda, until the oxide of tin which separates out at first is redissolved in the excess of alkali the liberated amine is driven over with steam. Further, volatile or non-volatile amines can be extracted from an alkaline solution by a proper solvent, like ether. But this process is often troublesome, since the alkaline tin solution forms an emulsion with ether, which subsides with great difficulty. If the free amine is solid, it may be obtained by filtering off the alkaline liquid. In many cases, where a non-volatile amine is under examination, it is advisable to predpitate the tin before liberating the amine. This is done by diluting the add solution with much water, heating on the water-bath, and as soon as the liquid has reached the temperature of the bath, hydrogen sulphide is passed into it. The tin is predpitated as stannous or stannic sulphide this is separated from... 

Alcobo/.—The product of the fermentation of sugar, and is contained in all fermented liquors. It is aoolorleeefluid, boUsat 178 F. and bums without smoke. The volatile oils and resins are dissolved by it, as well as many adds and salts, the caustic alkalies, etc. The resulting compounde of the adds upon alcohol are called etheie. 

Yellowish, transparent, flammable liquid penetrating fragrant, somewhat fruity odor. Unstable and dec on exposure to air and light. The pure nitrite has d 0.875. bp 97-99. but volatilizes readily at much lower temps, ng 1.3871. Very slightly sol in water miscible with ale, chloroform, ether. Caution Forms an explosive mixture with air or oxygen. Keep in tightly closed containers protected from light and in cool place. Incompat Alcohol, antipyrine, caustic alkalies, alkaline carbonates, potassium iodide, bromides, ferrous salts. 

Blackish-brown, viscous liquid heavier than water empy-reumatic odor and sharp taste. Slightly sol in water sol in ale, chloroform, ether, acetone, glacial acetic acid, fixed and volatile oils, and in solns of caustic alkalies. Principal con -stituents turpentine, resin, guaiacol, creosol, methylcreosol, phenol, phlorol. toluene, xylene, and other hydrocarbons. 

Light yellow, brittle, elongated tears translucent with vitreous fracture crumbles 10 powder when masticated. Insol in water, benzene, petr ether. Sol in alcohol, ether, acetone, hot caustic alkalies partially sol in chloroform, volatile oils, oil turpentine, carbon disulfide. 

Crystals, mp 51.S, bp about 233. Appreciably volatile at 100° volatilizes in water vapors. Characteristic odor pungent, somewhat caustic taste, dj5 0.9699. nff 1.5227 njf 1.5204. One gram dissolves in about 1000 ml water, I ml alcohol, 0.7 ml chloroform, 1.5 ml ether, 1.7 ml olive oil at 25°. Sol in glacial acetic acid, oils, fixed alkali hydroxides. LDjj Orally in rats 980 mg/kg (Jenner). 

Work-Up of Reaction Mixture. Soluble iron is generally precipitated with alkali, using caustic soda, soda ash, lime, or magnesia. Where the amine is volatile, it may be isolated by steam distillation or by vacuum distillation from the iron oxide cake after distilling off the water. In the latter case, an efficient scraper agitator must be used to keep the iron oxide from lumping and occluding the product. Where the final amine is soluble in alkaline solution, as is the case with sulfonic acids, carboxylic acids, or sulfonamides, the iron oxide cake is filtered off and the amine isolated from the filtrate. 

The action of steam on a-naphthalenesulfonic acid similarly yields naphthalene. Practically all aromatic sulfonic acids may be hydrolyzed with mineral acids to the parent hydrocarbons, but each sulfonic acid requires a specific minimiim temperature. a-Naphthalenesulfonic acid hydrolyzes at a much lower temperature than the beta compound. However, the beta compound with fused caustic acts quite like the corresponding benzenesulfonic acid to give /3-naphthol, sodium sulfite, and water. Under certain conditions, steam may replace the more expensive fused caustic alkalies in the hydrolysis of aromatic sulfonates that are volatile with steam ... 

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