Chief

White crystals, m.p. 114" C. Manufactured by reacting aniline with excess ethanoic acid or ethanoic anhydride. Chief use is in the manufacture of dye intermediates such as p-nitro-acetanilide, p-nitroaniline and p-phenylene-diamine, in the manufacture of rubber, and as a peroxide stabilizer. 

Agar occurs as a cell-wall constituent of the red marine algae Rho ophyceae, from which it is extracted by hot water, and marketed as a dry powder, flakes, or strips. It dissolves in hot water and sets on cooling to a jelly at a concentration as low as 0-5%. Its chief uses are as a solid medium for cultivating micro-organisms, as a thickener, emulsion stabilizer in the food industry and as a laxative. 

Its chief outlet is as an intermediate in the preparation of flavanthrene and indanthrene. 

Prepared by reduction of 4-nitrophenol or 4-nitrosophenoi. Can be diazotized and used as a first component in azo-dyes. Chief outlet is for sulphur dyes in which it is fused with sodium polysulphides. L/sed as a photographic developer. 

CioHi O. White leaflets, with a strong smell and sweet taste, m.p. 22 C, b.p. 235 C. The chief constituent of anise and fennel oils and other essential oils, from which it is manufactured. It can also be prepared from anisole (meihoxybenzene). It is widely used for flavouring pharmaceuticals and dentifrices, and in perfumery. 

Its chief importance is as a source of cinnamic acid by condensation with sodium ethan-oate and ethanoic anhydride and as a source of triphenylmethane dyestuffs by condensation with pyrogallol, dimethylaniline, etc. It is also used in the manufacture of perfumes. 

CCl3CH(OH)2, C3H3CI3O2. Crystallizes in large, colourless prisms having a peculiar odour m.p. 57"C, b.p. 91-5 C. Manufactured by adding the calculated amount of water to chloral. For other properties see chloral. Its chief use is as a hypnotic. 

Prepared by the direct nitration of naphthalene with a mixture of nitric and sulphuric acids. Its chief use was for the preparation of l-naphthyiamine and its derivatives. 

C21H36O2. M,p. 238°C. There are four isomeric pregnane-3,20-diols differing only in the orientation of the hydroxyl groups at positions 3 and 20 and with the 5/ configuration. Only the 3a,20a occurs naturally. It is formed by reduction of progesterone in the liver and is the chief urinary metabolite of it, being... 

The mixture of xylidines has been used as a first component of azo-dyes. The chief constituent of the mixture is m-xylidine (4-amino-1,3-xylene). It can be separated by crystallization from glacial ethanoic acid. It is also used for the preparation of azo-dyes. 

Various kinds of potentials have been referred to in the course of this and the preceding chapter, and their interrelation is the subject of the present section. The chief problem is that certain types of potential differences are physically meaningful in the sense that they are operationally defined, whereas others that may be spoken of more vaguely are really conceptual in nature and may not be definable experimentally. 

Generally speaking, intermolecular forces act over a short range. Were this not the case, the specific energy of a portion of matter would depend on its size quantities such as molar enthalpies of formation would be extensive variables On the other hand, the cumulative effects of these forces between macroscopic bodies extend over a rather long range and the discussion of such situations constitutes the chief subject of this chapter. 

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