(1) Quantitative precipitation of barium as its oxalate hemihydrate was made possible by employing 50% alcohol as washing solution and by drying the precipitate at 100°—105°C. for 2 hrs. (2) Sod. chloride, pot. chloride, pot. nitrate and amm. chloride produce little influence on this determination, while amm. nitrate positively effects the estimation. (3) It was found that barium can be determined volumetrically by titrating with potassium permanganate the oxalic acid which is formed when the barium oxalate is decomposed with nitric acid.
(1) The kinetic method was applied to the vapor pressure of regular solution; the result being in agreement with that of the statistical method. (2) New semi-empirical equations having simple form were derived for the vapor pressures of binary and ternary mixtures of liquids and satisfactory agreements of these equations with the experimental data were illustrated in regard to about 20 examples.
As the first step in a series of works on the mechanical behavior of a concentrated hydrogel of agar-agar, the experimental determination of its elastic behavior in compression was made. An apparatus which could record a compression stress-strain curve automatically was devised and used to obtain the results reported in this paper. Influences of tem-perature, concentration, and gelation time upon the modulus of elasticity (Young’s) were considered and plotted in Figures 4, 5 and 6.
(1) The rate constants and the activation energies of the thermal dissociation of symdimethylurea, asym-dimethylurea and asymphenylethylurea were determined. (2) It was demonstrated that the substituents have great influence on the dissociation reaction.
(1) The rate constant and the activation energy of thermal dissociation of phenylcarbaminic acid phenylester in butyric acid are determined. (2) It has been made clear on the basis of reaction mechanism that dissociation of ester linkage requires larger activation energy than that of urea linkage.
The authors studied the electrolytic reduction of benzoic acid and compared the yield of the reduction product obtained under various pressures of hydrogen and carbon dioxide with that obtained in an open vessel. The effect of pressure in the course of electrolytic reduction was discussed and it was found that the reduction product differed according to the pressure.
1. Three cellulose acetates from cotton linters, Kayaceta and a domestic pulp were fractionally precipitated from acetone solution with ethanol, and viscosity measurements in acetone solution and pentosan determinations by paper chromatography of the individual fractions were made. 2. Another acetate from Rayaceta was again fractionated into five fractions and viscosities in acetone and cupriethylene diamine solution and pentosan contents of the individual fractions were determined. 3. The results showed a close relationship between the initial acetone-insoluble fractions or in acetone haze-producing fractions and their pentosan content. These fractions include abnormal materials which show low viscosity (probably low D. P.) in cupriethylene diamine solution as well as in acetone. They are in-cluded much in the acetates from wood pulps. 4. It could not be decided whether these acetone-insoluble fractions were due to association by salt bridge effect of calcium ions between carboxyl or sulfuric half-ester groups, or due to the remaining structure of wood tissues. 5. The chain-length distributions of the cellulose acetates from wood pulp seem to be more heterogeneous than those from cotton linters.
By oxidation of ipomoeamarone and its semicarbazone with potassium permanganate, ceratonic acid (ipomeanic acid) (II), C12H20O4, and ipomic lactone (III), C11H18O3, were obtained. The ketonic group of ipomoeamarone was proved to be an isoamyl ketone by the oxidation of the reaction product of Grignard’s reagent. These experiments led us to conclude that ipomoeamarone is represented by the provisional constitution (I).