The azo-group is particularly active, both the aliphatic and aromatic compounds being coloured.
The same increase accompanies the introduction of the amino group into aromatic nuclei.
Numerous nitroso compounds are met with in the aromatic series.
In 1900 Bielefeldt found that a fulminate placed on top of an aromatic nitro compound, such as trinitrotoluene, formed a useful detonator; this discovery has been especially taken advantage of in Germany, in which country detonators of this nature are being largely employed.
The aromatic and irritating fumes emitted by burning amber are mainly due to this acid.
Hantzsch (Ber., 1901, 34, p. 3337) has shown that in the action of alcohols on diazonium salts an increase in the molecular weight of the alcohol and an accumulation of negative groups in the aromatic nucleus lead to a diminution in the yield of the ether produced and to the production of a secondary reaction, resulting in the formation of a certain amount of an aromatic hydrocarbon.
CYPRESS (Cupressus), in botany, a genus of fifteen species belonging to the tribe Cupressineae, natural order Coniferae, represented by evergreen aromatic trees and shrubs indigenous to the south of Europe, western Asia, the Himalayas, China, Japan, north-western and north-eastern America, California and Mexico.
Certain crude oils have also been found to contain camphenes, naphthalene and other aromatic hydrocarbons.
There also exists an extensive class of compounds termed the " heterocyclic series " - these compounds are derived from ring systems containing atoms other than carbon; this class is more generally allied to the aromatic series than to the aliphatic.
Long-continued treatment with halogens may, in some cases, result in the formation of aromatic compounds; thus perchlorbenzene, C 6 C1 6, frequently appears as a product of exhaustive chlorination, while hexyl iodide, C 6 H 13 I, yields perchlorand perbrom-benzene quite readily.
Von Liebig discovered, in 1834, an interesting aromatic compound, potassium carbon monoxide or potassium hexaoxybenzene, the nature of which was satisfactorily cleared up by R.
This is obviously unsymmetrical, consisting of an aliphatic and an aromatic nucleus; Claus explained the formation of the same phthalic acid from the oxidation of either nucleus by supposing that if the aromatic group be oxidized, the aliphatic residue assumes the character of a benzene nucleus.
The molecule is aromatic but not benzenoid; however, by the reduction of one half of the molecule, the other assumes a benzenoid character.
(7) (2) Phenanthrene is regarded by Armstrong as represented by (3), the lateral rings being benzenoid, and the medial ring fatty; Bamberger, however, regards it as (4), the molecule being (3) (4) entirely aromatic. An interesting observation by Baeyer, viz.
The more important types are derived from aromatic nuclei, benzene, naphthalene, &c.; the ortho-di-derivatives of the first named, lending themselves particularly to the formation of condensed nuclei.
Thus ortho-phenylene diamine yields the following products: N H N ./`N; Xn NZ In some cases oxidation of condensed benzenoid-heterocyclic nuclei results in the rupture of the heterocyclic ring with the formation of a benzene dicarboxylic acid; but if the aromatic nucleus be weakened by the introduction of an amino group, then it is the benzenoid nucleus which is destroyed and a dicarboxylic acid of the heterocyclic ring system obtained.
The oxidation with nitric acid in sealed tubes at a temperature of 150° to 200° for aliphatic compounds, and 250° to 260° for aromatic compounds, is in common use, for both the sulphur and phosphorus can be estimated, the former being oxidized to sulphuric acid and the latter to phosphoric acid.
In the aromatic compounds there is no regularity between the increments due to the introduction of methyl groups into the benzene nucleus or side chains; the normal value of 20 0 -21° is exhibited, however, by pyridine and its derivatives.
A similar depression is presented by methyl alcohol (67°) and methyl ether (-23 °) Among the aromatic di-substitution derivatives the ortho compounds have the highest boiling-point, and the meta boil at a higher, or about the same temperature as the para compounds.
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.
These formulae, however, only apply to aliphatic amines; the results obtained in the aromatic series are in accordance with the usual formulae.
Of the aromatic compounds azo-benzene is bright orange-red, and a-azonaphthalene forms red needles or small steel-blue prisms. The azogroup, however, has little or no colouring effect when present in a ring system, such as in cinnolene, phthalazine and tolazone.
SALICYLIC ACID (ortho-hydroxybenzoic acid), an aromatic acid, C 6 H 4 (OH)(CO 2 H), found in the free state in the buds of Spiraea Ulmaria and, as its methyl ester, in gaultheria oil and in the essential oil of Andromeda Leschenaultii.
Salicylic acid and salicin (q.v.) share the properties common to the group of aromatic acids, which, as a group, are antiseptic without being toxic to man - a property practically unique; are unstable in the body; are antipyretic and analgesic; and diminish the excretion of urea by the kidneys.
By the ancients the country was called regio romataica, from the abundance of aromatic plants which it produced.
These slopes are the home of aromatic flora which yields myrrh and frankincense.
His earlier work included an investigation of succinic acid, and the preparation of phenyl cyanide (benzonitrile), the simplest nitrile of the aromatic series; but later his time was mainly occupied with questions of technology and public health rather than with pure chemistry.
Beckmann, Ber., 1886, 1 9, p. 9 8 9; 188 7, 20, p. 2580), yielding as final products an acid-amide or anilide, thus: RC(:N OH)R'-RC(OH) :NR' ---> As regards the constitution of the oximes, two possibilities exist, namely >C: NOH, or > C' ?, and the first of these is presumably correct, since on alkylation and subsequent hydrolysis an alkyl hydroxylamine of the type NH 2 OR is obtained, and consequently it is to be presumed that in the alkylated oxime, the alkyl group is attached to oxygen, and the oxime itself therefore contains the hydroxyl group. It is to be noted that the oximes of aromatic aldehydes and of unsymmetrical aromatic ketones frequently exist in isomeric forms. This isomerism is explained by the HantzschWerner hypothesis (Ber., 1890, 23, p. II) in which the assumption is made that the three valencies of the nitrogen atom do not lie in the same plane.
In those parts of the desert which have a hard level soil of clay, a few stunted mimosas, acacias and other shrubs are produced, together with rue, various bitter and aromatic plants, and occasionally tufts of grass.
ACETOPHENONE, or PHENYL-METHYL KETONE, C8H8O or C6H5CO.CH3, in chemistry, the simplest representative of the class of mixed aliphatic-aromatic ketones.
The aromatic aldehydes resemble the aliphatic aldehydes in most respects, but in certain reactions they exhibit an entirely different behaviour.
The body was embalmed and filled with aromatic herbs, and then brought to this region, passing through the lands of various tribes.
Aromatic Nitro Compounds.-The aromatic nitro compounds are generally obtained by the direct action of nitric acid.
Sandmeyer, Ber., 1887, 20, p. 1494) by the action of copper powder on the double salt formed by the addition of potassium mercuric nitrite to diazonium nitrites; and by the oxidation of primary aromatic amines (E.
The nitro group in the aromatic series is bound very firmly in the molecule and is not readily exchanged for other groups.
The electrolytic reduction of the aromatic nitro compounds gives rise to substituted hydroxylamines which are immediately transformed into aminophenols or amines.
The Brazilian flora is also rich in medicinal and aromatic plants, dye-woods, and a wide range of gum and resin-producing shrubs and trees.
Cinnamic aldehyde ((3-phenyl acrolein), C6H5ï¿½CH: CHï¿½CHO, an unsaturated aromatic aldehyde, is the chief constituent of cinnamon oil.
The following diagrams illustrate these statements: - C ` H C OH HC /CH HC CH HC,/CH 'N/ HC CH CH CH From the benzene nucleus we can derive other aromatic nuclei, graphically represented by fusing two or more hexagons along common sides.
Other hydrocarbon nuclei generally classed as aromatic in character result from the union of two or more benzene nuclei joined by one or two valencies with polymethylene or oxidized polymethylene rings; instances of such nuclei are indene, hydrindene, fluorene, and fluoranthene.
This and other facts connected with the stability of benzenoid compounds are clearly shown when we consider mixed aliphatic-aromatic hydrocarbons, i.e.
This compound is readily oxidized to benzoic acid, C 6 H 5 000H, the aromatic residue being unattacked; nitric and sulphuric acids produce nitro-toluenes, C6H4 CH3 N02j and toluene sulphonic acids, C 6 H 4 CH 3 SO 3 H; chlorination may result in the formation of derivatives substituted either in the aromatic nucleus or in the side chain; the former substitution occurs most readily, chlor-toluenes, C 6 H 4 CH 3 Cl, being formed, while the latter, which needs an elevation in temperature or other auxiliary, yields benzyl chloride, C 6 H 5 CH 2 C1, and benzal chloride, C 6 11 5 CHC1 2.