noun
definition
The univalent hydrocarbon radical, CH3-, formally derived from methane by the loss of a hydrogen atom; a compound or part of a compound formed by the attachment of such a radical.
Examples of methyl in a Sentence
Its methyl derivatives yield the corresponding carboxylic acids when oxidized by potassium permanganate.
Many organic compounds of boron are known; thus, from the action of the trichloride on ethyl alcohol or on methyl alcohol, ethyl borate B(OC2H5)3 and methyl borate B(OCH 3) 3 are obtained.
By passing the vapour of this compound through a red-hot tube, it yields the isomeric a0- pyridylpyrrol, the potassium salt of which with methyl iodide gives a substance methylated both in the pyridine and pyrrol nuclei.
By distillation over lime, the methyl group is removed from the pyridine ring, and the resulting a- pyridyl-Nmethylpyrrol gives i-nicotine on reduction.
It is the methyl ester of a neutral body colchicein, which may be obtained in white acicular crystals.
Notwithstanding these errors, the value of the " ethyl theory " was perceived; other radicals - formyl, methyl, amyl, acetyl, &c. - were characterized; Dumas, in 1837, admitted the failure of the etherin theory; and, in company with Liebig, he defined organic chemistry as the " chemistry of compound radicals."
By his own investigations and those of Sir Edward Frankland it was proved that the radical methyl existed in acetic acid; and by the electrolysis of sodium acetate, Kolbe concluded that he had isolated this radical; in this, however, he was wrong, for he really obtained ethane, C 2 H 6, and not methyl, CH 3.
From similar investigations of valerianic acid he was led to conclude that fatty acids were oxygen compounds of the radicals hydrogen, methyl, ethyl, &c., combined with the double carbon equivalent C2.
Henry started with methyl iodide, the formula of which we write in the form CI a H b H c H d.
The same methyl iodide gave with potassium cyanide, acetonitril, which was hydrolysed to acetic acid; this must be C(Coch) a H b H c H d.
This compound may be considered as derived from methane, CH 4, by replacing a hydrogen atom by the monovalent group CH 3, known as methyl; hence ethane may be named " methylmethane."
By introducing a methyl group we may obtain CH 3.
Moreover, while methylamine, dimethylamine, and trimethylamine increase in basicity corresponding to the introduction of successive methyl groups, phenylamine or aniline, diphenylamine, and triphenylamine are in decreasing order of basicity, the salts of diphenylamine being decomposed by water.
In the second group, we may notice the application of litmus, methyl orange or phenolphthalein in alkalimetry, when the acid or alkaline character of the solution commands the colour which it exhibits; starch paste, which forms a blue compound with free iodine in iodometry; potassium chromate, which forms red silver chromate after all the hydrochloric acid is precipitated in solutions of chlorides; and in the estimation of ferric compounds by potassium bichromate, the indicator, potassium ferricyanide, is placed in drops on a porcelain plate, and the end of the reaction is shown by the absence of a blue coloration when a drop of the test solution is brought into contact with it.
Referring to the esters C9H1802 previously mentioned, it is seen that the highest boilingpoints belong to methyl octoate and octyl formate, the least symmetrical, while the minimum belongs to amyl butyrate, the most symmetrical.
The same difference attends the introduction of the methyl group into many classes of compounds, for example, the paraffins, olefines, acetylenes, aromatic hydrocarbons, alcohols, aldehydes, ketones and esters, while a slightly lower value (157.1) is found in the case of the halogen compounds, nitriles, amines, acids, ethers, sulphides and nitro compounds.
To Jaeger is due the determination of the topic parameters of certain haloid-derivatives, and, while showing that the morphotropic effects closely resemble those occasioned by methyl, he established the important fact that, in general, the crystal form depended upon the orientation of the substituents in the benzene complex.
The hydroxyl group also resembles the methyl group in its morphotropic effects, producing, in many cases, no change in symmetry but a dimensional increase in one direction.
By the direct action of hydroxylamine on a methyl alcohol solution of mesityl oxide in the presence of sodium methylate a hydr oxylamino - ketone, diacetone hydroxylamine, (CH 3) 2 C(Nhoh) CH20OCH3,is formed.
If an aqueous solution of methyl acetate be allowed to stand, a slow decomposition goes on.
The reaction is a general one for all aldehydes with zinc methyl and zinc ethyl, but not with the higher zinc alkyls.
Grignard (Comptes Rendus, 1900 et seq.) showed that aldehydes combine with magnesium alkyl iodides (in absolute ether solution) to form addition products, which are decomposed by water with the formation of secondary alcohols, thus from acetaldehyde and magnesium methyl iodide, isopropyl alcohol is obtained.
It is also produced by the action of sodium on a mixture of epichlorhydrin and methyl iodide, C 3 H S OC1+CH 3 I+2Na= C 3 H 4 0+NaI+NaC1+CH 4.
When methyl iodide is used, nitromethane is the sole product, but the higher homologues give more or less of the isomeric nitrous esters.
Fraser proved that by substitution of molecules in certain compounds a stimulant could be converted into a sedative action; thus by the addition of the methyl group CH 2 to the molecule of strychnine, thebaine or brucine, the tetanizing action of these drugs is converted into a paralysing action.
Dumas obtained barium methyl carbonate by the action of carbon dioxide on baryta dissolved in methyl alcohol (Ann., 1840, 35, p. 283).
Rhamnose or isodulcite, a component of certain glucosides, fucose, found combined in seaweeds and chinovose, present as its ethyl ester, chinovite, in varieties of quina-bark, are methyl pentoses.
Methyl and phenyl anthracenes are known; phenyl anthranol (phthalidin) being somewhat closely related to the phenolphthaleins.
Tetramethylammonium iodide, N(CH 3) 4 I, is the chief product obtained by the action of methyl iodide on ammonia (Hofmann).
On dry distillation it is resolved into trimethylamine and methyl alcohol.
Examples are water and methyl or ethyl alcohol.
Discovered by Boyle in 1661, it was first carefully studied by Dumas and Peligot in 1831; its synthesis from its elements (through methane and methyl chloride) was effected by Berthelot in 1858.
It is manufactured by distilling wood in iron retorts at about 50o C., when an aqueous distillate, containing methyl alcohol, acetone, acetic acid and methyl acetic ester, is obtained.
Methyl alcohol is also obtained in the dry distillation of molasses.
The amount of methyl alcohol present in wood spirit is determined by converting it into methyl iodide by acting with phosphorus iodide; and the acetone by converting it into iodoform by boiling with an alkaline solution of iodine in potassium iodide; ethyl alcohol is detected by giving acetylene on heating with concentrated sulphuric acid, methyl alcohol, !under the same circumstances, giving methyl ether.
Chemically it is the methyl ester of arecaidine.
Methyl and dimethylalloxans are also known, the former being obtained on oxidation of methyl uric acid, and the latter on oxidation of caffeine.
When the reaction is complete the acid is neutralized with soda, and the phenyl methyl pyrazolone extracted with ether and distilled in vacuo.
Methyl orange (helianthin, gold orange, Mandarin orange), (CH 3) 2 N C 6 H 4 N 2 C 6 H 4 SO 3 Na, is the sodium salt of paradimethylaminobenzene-azo-benzene sulphonic acid.
Methyl orange is used largely as an indicator.
The constitution of methyl orange follows from the fact that on reduction by stannous chloride in hydrochloric acid solution it yields sulphanilic acid and para-aminodimethyl aniline.
Azoxy Compounds, R N O N R', are usually yellow or red crystalline solids which result from the reduction of nitro or nitroso compounds by heating them with alcoholic potash (preferably using methyl alcohol).
The benzyl group shows this remarkably well, since we see that phenyl is present, as is also methyl.
Well-dried hydroxylamine hydrochloride is dissolved in methyl alcohol and mixed with sodium methylate; a solution of methyldichloramine in absolute ether is then added and an ethereal solution of diazomethane distils over.
Diazomethane converts it into the methyl derivatives of isocyanic acid, and nitramide, NH2N02.
Hyponitrous acid is formed by passing nitrous fumes into its methyl alcohol solution.
The ethers are neutral volatile liquids (the first member, methyl ether, is a gas at ordinary temperature).
Methyl ethyl ether, CH 3.0.
For diethyl ether see Ether, and for methyl phenyl ether (anisole) and ethyl phenyl ether (phenetole) see Carbolic Acid.
When mesitylene is used, the reaction does not proceed beyond the aldehyde stage since hydrocarbon formation is prevented by the presence of a methyl group in the ortho-position to the -CHO group. Acids and alkalis are in general without action on nickel carbonyl.