Soc., 18 9 8, 73, p. 35 2) as a colourless liquid by the addition of hydroxylamine hydrochloride to an aqueous solution of formaldehyde in the presence of sodium carbonate; the resulting solution was extracted with ether and the oxime hydrochloride precipitated by gaseous hydrochloric acid, the precipitate being then dissolved in water, the solution exactly neutralized and distilled.
The reaction of formaldehyde on phenols: 0.
The original hypothesis of Baeyer suggested that the course of events is the following: the carbon dioxide is decomposed into carbon monoxide and oxygen, while water is simultaneously split up into hydrogen and oxygen; the hydrogen and the carbon monoxide unite to form formaldehyde and the oxygen is exhaled.
The formation of formaldehyde has till recently not been satisfactorily proved, though it has been obtained from certain leaves by distillation.
Recent investigations have confirmed Baeyers view of the formation of formaldehyde, but a different explanation has been recently advanced.
The first chemical change suggested is an interaction between carbon dioxide and water, under the influence of light acting through chlorophyll, which leads to the simultaneous formation of formaldehyde and hydrogen peroxide.
The formaldehyde at once undergoes a process of condensation oi- polymerization by the protoplasm of the plastid, while the hydrogen peroxide is said to be decomposed into water and free oxygen by another agency in the cell, of the nature of one of the enzymes of which we shall speak later.
Its tetramethyl-diamino derivative, which is formed by condensing formaldehyde with dimethyl-meta-aminophenol and subsequent elimination of water from the resulting diphenyl methane derivative, is the leuco base of pyronine, into which it passes by oxidation.
It behaves as a powerful reducing agent, and on hydrolysis with dilute mineral acids is decomposed into formaldehyde and hydroxylamine, together with some formic acid and ammonia, the amount of each product formed varying with temperature, time of reaction, amount of water present, &c. This latter reaction is probably due to some of the oxime existing in the form of the isomeric formamide HCO NH 2.
It appears to be synthesized in the plant tissues from carbon dioxide and water, formaldehyde being an intermediate product; or it may be a hydrolytic product of a glucoside or of a polysaccharose, such as cane sugar, starch, cellulose, &c. In the plant it is freely converted into more complex sugars, poly-saccharoses and also proteids.
The lower members of the series are neutral liquids possessing a characteristic smell; they are soluble in water and are readily volatile (formaldehyde, however, is a gas at ordinary temperatures).
The chief aldehydes are shown in the following table: - For formaldehyde see Formalin.
Oxidation gives formaldehyde, formic acid and carbonic acid; chlorine and bromine react, but less readily than with ethyl alcohol.
Jour., 1860, 158, p. 146); by heating aniline for red with nitrobenzene, concentrated hydrochloric acid and iron (Coupier, Ber., 1873, 6, p. 423); or by condensing formaldehyde with aniline and ortho-toluidine and oxidizing the mixture.
Bokorny, moreover, it appears that such filaments will yield :starch from formaldehyde when they are supplied with sodium -oxymethyl sulphonate, a salt which readily decomposes into formaldehyde and hydrogen sodium sulphite, an observation which has been taken to mean that formaldehyde is always a stage in the synthesis of starch.
It condenses readily with aldehydes, yielding with formaldehyde, on the addition of.
Knorr, Ann., 1886, 236, p. 69) or from aniline, acetone, formaldehyde and hydrochloric acid (C. Beyer, Jour.
It may also be prepared by condensing ay-dimethylquinoline and formaldehyde, the resulting a-ethanollepidine, C9H5 CH3N(CH2 CH2.OH), breaks down on heating and forms lepidine (W.
It was formerly thought that its action was due to the setting free of formaldehyde in the urine, but it is now known by the researches of P. Cammidge that this is not so.
The steps which lead from the appearance of formaldehyde to that of the first well-defined carbohydrate are again matters of speculation.
In 1861 Butlerow obtained a sugar-like substance, methylenitan, by digesting trioxymethylene, the solid polymer of formaldehyde, with lime.
The ketone, dihydroxyacetone, CH 2 OH CO CH 2 OH, was obtained by Piloty by condensing formaldehyde with nitromethane, reducing to a hydroxylamino compound, which is oxidized to the oxime of dihydroxyacetone; the ketone is liberated by oxidation with bromine water: 3H CHO + CH 3 NO 2 -- (CH 2 OH) 3 C NO 2 - (CH 2 OH) 3 C NH OH -- (CH 2 OH) 2 C: NOH - > (CH20H)2CO.
It may be prepared artificially by the oxidation of methyl alcohol and of formaldehyde; by the rapid heating of oxalic acid (J.
Formaldehyde behaves abnormally with magnesium benzyl bromide (M.