Terephthalic acid, formed by oxidizing para-diderivatives of benzene, or best by oxidizing caraway oil, a mixture of cymene and cuminol, with chromic acid, as almost insoluble in water, alcohol and ether; it sublimes without melting when heated.
Quinaldic acid (quinoline-a-carboxylic acid) is produced when quinaldine is oxidized by chromic acid.
Oxidizing agents convert anthracene into anthraquinone; the production of this substance by oxidizing anthracene in glacial acetic acid solution, with chromic acid, is the usual method employed for the estimation of anthracene.
Reducing agents, such as sulphurous acid and sulphuretted hydrogen, convert the chromates into chromic salts.
Solutions of chromic chloride in presence of excess of acid are green in colour.
The important oxidizing agents include: oxygen, ozone, peroxides, the halogens chlorine and bromine, oxyacids such as nitric and those of chlorine, bromine and iodine, and also chromic and permanganic acid.
Styrolene is oxidized by nitric or chromic acids to benzoic acid; reduction gives ethylbenzene; hydrochloric and hydrobromic acids yield a-haloid ethylbenzenes, e.g.
Nitric acid oxidizes it to adipic acid, and chromic acid to cyclo-hexanone.
It may be condensed to a dark red liquid which is decomposed by moist air into chromic acid and chromic fluoride.
On oxidation .ith chromic acid it forms a quinone, C 15 H 8 0 2, and an a-diphenylene keto carboxylic acid C E I-4 3.