rt, of its normal supply of water.
Pyrocatechin readily condenses to form heterocyclic compounds; cyclic esters are formed by phosphorus trichloride and oxychloride, carbonyl chloride, sulphuryl chloride, &c.; whilst ortho-phenylenediamine, o-aminophenol, and o-aminothiophenol give phenazine, phenoxazine and thiodiphenylamine.
POLYMETHYLENES, in chemistry, cyclic compounds, the simplest members of which are saturated hydrocarbons of general formula C 7, H 2nj where n may be r to 9, and known as tri-, tetra-, penta-, hexa-, and hepta-methylene, &c., or cyclo- propane, -butane, -pentane, -hexane, -heptane, &c.: - CH 21 CH 2 CH 2 CH2.CH2 CH2 CH2 CH2?C1H,, I I H ?
Senderens, loc. cit.); by the reduction of cyclic esters with CH 2 CH2 / NCH2- -CHI sodium and alcohol (L.
Blanc, Comptes rendus, 1903, 136, p. 1676; 137, p. 60); and by the addition of the elements of water to the unsaturated cyclic hydrocarbons on boiling with dilute acids.
When a flower consists of parts arranged in whorls it is said to be cyclic, and if all the whorls have an equal number of parts and are alternate it is eucyclic (figs.
In Symmetry contrast to the cyclic flowers are those, as in Magnoli of the flower.
If the fluctuations are irregular and non-periodic, teristics the sound is called a noise; if they are cyclic and follow a regular and sufficiently rapid periodic law, the sound is musical.
Deferring the detailed discussion of cyclic or ringed hydrocarbons, a correlation of the various types or classes of compounds which may be derived from hydrocarbon nuclei will now be given.
It will be seen that each type depends upon a specific radical or atom, and the copulation of this character with any hydrocarbon radical (open or cyclic) gives origin to a compound of the same class.
It may be noticed here that cyclic nuclei can only contain the groups > CH 2.
Cyclic Hydrocarbons and Nuclei.
Zincke; and his researches have led to the discovery of many chlorinated oxidation products which admit of decomposition into cyclic compounds containing fewer carbon atoms than characterize the benzene ring, and in turn yielding openchain or aliphatic compounds.
During recent years an immense number of ringed or cyclic compounds have been discovered, which exhibit individual characters more closely resembling benzene, naphthalene, &c. than purely aliphatic substances, inasmuch as in general they contain double linkages, yet withstand oxidation, and behave as nuclei, forming derivatives in much the same way as benzene.
As a useful preliminary it is convenient to divide heterocyclic ring systems into two leading groups: (I) systems resulting from simple internal dehydration (or similar condensations) of saturated aliphatic compounds - such compounds are: the internal anhydrides or cyclic ethers of the glycols and thioglycols (ethylene oxide, &c.); the cyclic alkyleneimides resulting from the splitting off of ammonia between the amino groups of diaminoparaffins (pyrrolidine, piperazine, &c.); the cyclic esters of oxycarboxylic acids (lactones, lactides); the internal anhydrides of aminocarboxylic acids (lactams, betaines); cyclic derivatives of dicarboxylic acids (anhydrides, imides, alkylen-esters, alkylenamides, &c.).
The associations of his home, not far from Corinth, where Arion was said to have established the cyclic choruses of satyrs, may account for his preference for this kind of drama.
Wallach (Ann., 1900, 312, p. 171) has shown that the saturated cyclic ketones yield oximes which by an application of the Beckmann reaction are converted into isoximes, and these latter on hydrolysis with dilute mineral acids are transformed into acyclic amino-acids; thus from cyclohexanone, e-amidocaproic acid (e-leucine) may be obtained: CH2" C NOH C CH 2 CH 2 7: ?12?CH2 CH2 NH /CH2 CH2 C02H CH2', An ingenious application of the fact that oximes easily lose the elements of water and form nitriles was used by A.
The cycle of Guillaume has more unity than the other great cycles of Charlemagne or of Doon de Mayence, the various poems which compose it forming branches of the main s