The magnetic susceptibilities of condensed polynuclear aromatic compounds with higher molecular weights (ten hydrocarbons and twelve quinones) have been measured by the Gouy method, and the diamagnetic anisotropies have been approximately evaluated. The diamagnetic anisotropy becomes progressively large as the number of rings increases, when the aromatic condensation takes place in the manner of the closely compact arrangement of rings; while, when it is not the case, it depends strikingly upon the molecular structure. When the diamagnetic anisotropy has a smaller value, notwithstanding the molecule is made of a large number of rings, the localization of the π-electrons or some other excited states must be assumed. Such a case is found, when a molecule is not made of the aromatically conjugated system as a whole but separated into two predominant nuclei, as meso-naphthodianthrene and violanthrone, or when a molecule is made of a long shaped structure as pyranthrene or violanthrene.
The surface films of some linear non-electrolytic polymers such as polyvinyl acetate, polyvinyl stearate and copolymers between them were studied at the air/water interface by measuring surface pressure, and surface potential in relation to the area occupied per monomer. The surface concentration was changed by two different methods, namely by the compression with barrier and by the successive addition by injection with micrometer syringe. Polyvinyl acetate gave the film of expanded type and was hardly affected by its degree of polymerization. Polyvinyl stearate gave the film of coherent type and its F—A curve resembled that of polyoctadecyl methacrylate. The copolymer with moderate content of vinyl stearate showed the smaller limiting area per monomer than polymers of its constituents. The results were discussed in relation to the molecular model and to the methods adopted to change the surface concentration.
The coulometric method with a constant current was used for the microanalysis of thiourea. An ammoniacal solution of silver bromide was added to thiourea solution and the liberated bromide equivalent to thiourea was titrated with electrolytically generated silver ion in an acid solution. A milligram amount of thiourea was satisfactorily determined with the standard deviation of about 0.01 mg. and the method is also applicable to submilligram amounts of thiourea. Simultaneous analysis of thiourea and ammonium thiocyanate in a mixture was made using 90% acetone solution.
Egyptian cotton linters, its purified linters, Japanese red pine and beech were hydrolyzed. It has been shown by paper chromatography that the hydrolyzates contain certain monosaccharides, uronic acids and amino acids. Raw cotton linters have been found to contain, besides glucose, about 1,5% arabinose, and a small amount of glactose, glucuronic acid and galacturonic acid. The amounts of the various amino acids contained in the hydrolyzates of raw cotton linters, red pine and beech are somewhat different from each other, but the kinds of the amino acids are the same and they are assumed to be cystine, aspartic acid, aspargine, arginine, glutamic acid, alanine and tryptophane. Glutamic acid changes to pyrrolidoncarboxylic acid in the process of hydrolysis of the materials and shows special colorizations reactions with ninhydrin and bromo-phenol-blue indicator. Purified cotton linters and sulfate rayon pulps treated by alkali cooking do not contain any amino acid, but sulfite rayon pulps contain cystine, alanine and pyrrolidoncarboxylic acid.