Studies in qualitative organic analysis

SEMI -MICRO SCALE: Alkyl halides were successfully identified by formation of S- alkyl- isothiourea picrates. The derivatives had convenient melting points, were stable, easily purified, and in most cases could be formed in a few minutes.Meta- and para- substituted C- nitrosocomnotiinds were identified by condensation with 2- phenylindole, but the standard method i.e. formation of azo-conmounds was found to be a method of identification of C-nitroso -compounds.An unsuccessful attempt was made to prepare 5-carboxy-2:4-dinitrophenylhydrazine for use in determining equivalents of carpoxy- hydrazones in identification of carbonyl compounds.2:4:5-Trinitrotoluene was tried and discarded as a reagent for aromatic amines.2:3:5- Trinitro-p-xylene was found to be inferior to 2:4:5-trinitrotoluene as a reagent for aliphatic amines.MICRO- SCALE: Oxidations of aromatic hydrocarbons in sealed tubes with dilute nitric acid were carried out on a thirty milligram scale but were only partly successful.Nitrations, acetylations, and identifications of amines with 2:4:5-trinitrotoluene, and phenylisothiocyanate were done on a two milligram scale without difficulty.COLOUR TESTS: A number of "pure" hydrocarbons were further purified by chromatographic adsorption without any diminution in fluorescence being apparent, except in the case of fluorene.Colours obtained with many aromatic and heterocyclic compounds in concentrated sulphuric acid alone, and on addition of benzal chloride were noted in visible and ultraviolet light.Compounds containing the cyclopentadiene structure CH₂ were detected by methyl alcoholic potassium hydroxide in presence of p-dinitrobenzene.Diamines were detected by ferric chloride in acetone solution.SUBLIMATION: Aryloxyacetic acids, and acids of high melting point containing more than one carboxyl group were sublimed on the Kofler melting point apparatus, characteristicreproducible sublimates being obtained provided definite conditions were strictly adhered to. The sublimates were photographed.In concluding the author wishes to express appreciation and thanks to Dr. Neil Campbell for his encouragement and unfailing interest during this research