摘要:

The densities of the anhydrous sodium salts of the fatty acids from caproic to stearic have been measured over a temperature range of 30° to 300 °C. and the results obtained correlated with the properties of lyophilic dispersions of sodium soaps in mineral oil.

ISSN:1923-4287    

DOI:10.1139/cjr47b-015

出版商:NRC Research Press    

年代:1947

数据来源: NRC

摘要:

The flow properties of anhydrous sodium stearate have been followed in some detail over the temperature range 45° to 140 °C., using an extrusion plastometer. Comparative results have been obtained at a single temperature with the sodium soaps of some of the lower fatty acids. The results indicate large changes in the properties of sodium stearate at 68° and 105 °C. An abrupt change is also observed when the number of carbon atoms in the soap is reduced below eight.

ISSN:1923-4287    

DOI:10.1139/cjr47b-016

出版商:NRC Research Press    

年代:1947

数据来源: NRC

摘要:

In the past, a dropping mercury electrode for polarographic work has consisted of a single capillary dipping in a solution. We have used two or more capillaries in parallel to increase cathode surface and thereby increase the diffusion current and the sensitivity of the instrument. The results indicate that each tip gives a diffusion current proportional to its calibration constant and that multi-tip electrodes give diffusion currents proportional to the sum of the capillary constants. Further, galvanometer oscillations are reduced considerably by the use of multi-tip electrodes. The use of multi-tip electrodes, therefore, makes it possible to extend the limits of detection and provides a means for reducing objectionable galvanometer oscillations.

ISSN:1923-4287    

DOI:10.1139/cjr47b-017

出版商:NRC Research Press    

年代:1947

数据来源: NRC

摘要:

The decomposition of hydrogen peroxide vapour has been investigated at low pressures (5 to 6 mm.) in the temperature range 50° to 420 °C., for the purpose of determining the effect of the nature and treatment of the active surfaces. The reaction was followed in an all-glass apparatus and, except in one case, with one-litre round flasks as reaction vessels. Soft glass, Pyrex, quartz, and metallized surfaces variously treated were used. In most cases the decomposition was found to be mainly of the first order but the rates varied markedly from one vessel to another, even with vessels made of the same type of glass. On a quartz surface the decomposition was preceded by an induction period at low temperatures. Fusing the glass vessels slowed the reaction considerably and increased its apparent activation energy; this effect was destroyed by acid washing. Attempts to poison the surface with hydrocyanic acid gave no noticeable result. The marked importance of surface effects at all temperatures is considered as an indication that the reaction was predominantly heterogeneous under the prevailing conditions. Values ranging from 8 to 20 kcal. were found for the apparent energy of activation. It is concluded that the decomposition of hydrogen peroxide vapour is not very specific as far as the nature of the catalyst is concerned.

ISSN:1923-4287    

DOI:10.1139/cjr47b-018

出版商:NRC Research Press    

年代:1947

数据来源: NRC

摘要:

The nitrates of starch, amylose, and amylopectin were treated with hot aqueous sodium hydroxide solution and the effect of this treatment upon each noted. This treatment does not cause appreciable denitration, nor does it result in a usefully stable nitrate. The nitrates of the starches are more resistant to alkali than is cellulose nitrate. Amylose nitrate appears to resemble cellulose nitrate in being more alkali-labile than either whole starch nitrate or amylopectin nitrate; this is consistent with its linear chain structure. The greater stability of amylose nitrate as compared to amylopectin nitrate is paralleled by a greater alkali-lability of the former, which indicates that the inherent instability of starch nitrate is not due to the presence of free terminal aldehyde groups present either in native starch or formed during the nitration process.

ISSN:1923-4287    

DOI:10.1139/cjr47b-019

出版商:NRC Research Press    

年代:1947

数据来源: NRC

摘要:

Cellobiose and maltose were nitrated and their properties studied to note the effect of the difference in glycosidic linkage (β- and α-respectively). Cellobiose octanitrate is more stable than maltose octanitrate as measured by the Abel test, and both are less stable than cellulose and starch nitrates. Neither of the octanitrates is sufficiently stable to permit of the application of the Bergmann–Junk test. If the stability of the cellulose nitrate building unit, namely, cellobiose octanitrate, carries over into its polymeric form, it would be expected that cellulose nitrate (characterized by 1,4-β-glucosidic linkages) should be inherently more stable than starch nitrate (α-1,4-glucosidic linkages).

ISSN:1923-4287    

DOI:10.1139/cjr47b-020

出版商:NRC Research Press    

年代:1947

数据来源: NRC

摘要:

Tertiary octyl, decyl, dodecyl, and hexadecyl mercaptans were investigated as modifiers in GR-S polymerizations.The rate of disappearance of these modifiers followed a first-order rate equation during the first half of the polymerization, in accordance with the theory of chain-transfer reactions. During the latter part of the reaction, an increased rate of disappearance generally occurred. A mechanism is suggested.The rate of disappearance increased with decreasing chain-length of the mercaptan. The intrinsic viscosities and molecular weight distributions of the polymers obtained at different conversions were related to the activity of each mercaptan as a modifier. Values for the regulating index of each mercaptan were calculated.The slow rate of disappearance of tertiary hexadecyl mercaptan leads to the formation of polymer that is relatively homogeneous in molecular weight, and this mercaptan is therefore a desirable modifier. However, after 50% polymerization, the regulator action shows a marked acceleration, leading to the formation of progressively lower molecular weight polymer and resulting in a spread in the molecular weight distribution.

ISSN:1923-4287    

DOI:10.1139/cjr47b-021

出版商:NRC Research Press    

年代:1947

数据来源: NRC

摘要:

The equilibrium diagrams of the systems: picric acid – 2,4-dinitrophenol, trinitrotoluene – 2,4-dinitrophenol, and picric acid – dinitrophenol – trinitrotoluene have been determined.As this investigation was carried out to find the suitability of various mixtures for shell filling, the densities of a number of liquid mixtures of the above components were determined. For the same reason, viscosities and crystallization velocities were investigated.The crystallization velocities were far from additive, the crystallization velocity of a mixture being less than that of either of the components. Tammann's type of curve, in which the velocity of crystallization attains a constant value after a certain degree of supercooling, was not obtained, but a maximum crystallization velocity resulted, in most cases, at about 20° to 30 °C. of supercooling. Comparison of viscosity and crystallization velocity shows that a direct relation does not exist, but increase of viscosity at constant temperature does always reduce the crystallization velocity.Addition of guncotton increased the viscosity of Shellite considerably without producing much effect on the crystallization velocity. The addition of a crystalline third component lowered both the melting point and the crystallization velocity.

ISSN:1923-4287    

DOI:10.1139/cjr47b-022

出版商:NRC Research Press    

年代:1947

数据来源: NRC