(1) It has been found that 2MgO·SnO2 is the only stable addition compound which is formed by the solid reaction between MgO and SnO2, and that the compound is soluble in 4N HCl. (2) While the reaction in dry oxygen begins at about 950°, it takes place more readily in open air, probably, due to the effect of the traces of reducing gases contained in air. (3) The reaction product seems to exist at first in an amorphous state, and, when the amount of which reaches to a certain value, 2MgO·SnO2 becomes to crystallize out smoothly; the later reaction proceeds by the diffusion of the components through this crystalline layer. (4) It has been considered that the main part of the reaction is controlled by the diffusion process, and the energy of activation of which has been estimated as about 100 Kilocalories per mole. (5) An induction period has been observed at the beginning of the reaction, and the energy of activation is very great when compared with those of the reactions hitherto studied.
(1) It has been confirmed that two stannates, 2CaO·SnO2 and CaO·SnO2, are formed by the solid reaction between the components, and both of them are soluble in 4N HCl. The crystal structure of CaO·SnO2, which has been considered as cubic, should correctly be assigned as rhombic with a unit cell size of a=3.93Å, b=3.99Å and c=3.87Å. (2) The reaction begins to take place at about 900°. The reaction product exists at first in an amorphous state; when the amount of which has reached a certain value, the reaction proceeds smoothly, forming CaO·SnO2. 2CaO·SnO2 is formed gradually when an excess of CaO is present. (3) It has been considered that the reaction is controlled by the diffusion of the components through the reaction product, and the energy of activation of CaO·SnO2 formation has been calculated as 85 Kilocalories per mole. (4) Whether the acidic component is TiO2 or SnO2, the energy of activation of the reaction with CaO has been found to be a little smaller than that of the reaction with MgO.
(1) Twenty seven higher nitro-derivatives of 2- and 3-bromo-, 2,6-, 3,6- and 1,8-dibromo-, 2,3,6-tribromo-, and 1,3,6,7- and 2,3,6,7-tetrabromobiphenylene oxides were newly obtained by nitrating the corresponding lower nitro-derivatives, and their constitutions were established. (2) The absorption curves of those bromonitro-compounds were compared with each other, and also with those of the corresponding nitrobiphenylene oxides, to the confirmation of their constitutions as a consequence. (3) In the nitration of the bromo- and bromonitro-biphenylene oxides, it was found that when the relative arrangements of the substituents at the 2- and 3-positions to the 1-position are the same as those of the same substituents at the 3- and 2-positions to the 4-position, the introduction of the nitro group more readily takes place at the 4-position than at the 1-position.
d-Allomethylose is obtained from l-rhamnose by a little modification of Levene’s method. And d-ribomethylse is prepared from d-allomethylose by Wohl’s method of degradation, obtaining on the way d-allomethyloxime (melting point, 146–146.5°, and [α]D18, +54°, 6 minutes after dissolution and −4° in equilibrium), tetracetyl d-allomethylonic nitrile (melting point 166.5∼167°), and d-ribomethylose diacetamide (melting point, 191°, and [α]D18, +7.4°). Equilibrium specific rotation, [α]D20, of d-ribomethylose is found to be +20°.