摘要:

The efficiency of jack chain packings, with alcohol-water mixtures, increases by only 13.2% with decrease in the size of the chain links from No. 18 to No. 22, while a drop in capacity of 36.7% is noted. If all factors are taken into consideration, No. 18 jack chain is the most desirable of those studied. The efficiency of Lessing rings, 0.22 in. in diameter, is higher than that of any of the chains studied, but the capacity is much less than that of No. 18 chain, and only slightly better than that of No. 22 chain.

ISSN:1923-4287    

DOI:10.1139/cjr37b-001

出版商:NRC Research Press    

年代:1937

数据来源: NRC

摘要:

The viscosity of monomeric vinyl acetate has been measured over a range of temperatures from 0° to 60 °C. Two equations were obtained which represent the results. The empirical equation is, and a theoretical equation is given as. The characteristic frequency has been obtained from the relation, where μ is the ratio between the latent heat of evaporation and the heat of cohesion,vwas found to be 2.17 × 1012.

ISSN:1923-4287    

DOI:10.1139/cjr37b-002

出版商:NRC Research Press    

年代:1937

数据来源: NRC

摘要:

Measurements were made of the amount of water vapor sorbed by beaten and unbeaten samples of kraft, unbleached sulphite and bleached sulphite wood pulps at relative vapor pressures ranging from 0 to 100%. Beating of the pulp made practically no difference to the degree of sorption at any relative vapor pressure. This indicated that beating caused no change in the hydration of the cellulose. Measurements were made of the sorption of methyl alcohol vapor by bleached sulphite, kraft and groundwood, and of the sorption of propyl alcohol vapor by bleached sulphite and cotton, all previously wetted with water and then dried. After sorption of alcohol, evacuation at room temperatures did not completely remove the alcohol. Measurements were also made of sorption of propyl alcohol by bleached sulphite and by cotton which had been dewatered by washing with propyl alcohol. The shape of the sorption curve was different for these samples, and the residual alcohol after evacuation was less. After a sample of cotton had been dried over phosphorus pentoxide in vacuo for a long period it was found to hold 0.35% of water by weight which could be removed by heating the cellulose to 100 °C. This was regained from the pentoxide on cooling the cellulose.The data are explained on the hypothesis that the crystalline submicroscopic elements of the cellulose structure are drawn together by internal tensile forces during the evaporation of the sorbed liquid, and that bonding between these elements may take place by the growing together of the crystal elements, leaving the structure internally stressed. On absorption, dissolution of these bondings takes place and the stresses are relieved as liquid enters the structure.

ISSN:1923-4287    

DOI:10.1139/cjr37b-003

出版商:NRC Research Press    

年代:1937

数据来源: NRC

摘要:

The composition of spruce methanol lignin prepared by the action of anhydrous methanol-hydrogen chloride on spruce meal was found to vary with the temperature and time of extraction. The reaction mixture contains two products, having methoxyl contents of 21.6 and 24%, respectively. Higher temperatures and longer time of heating favor formation of the latter. Long continued extraction of the crude methanol lignin with ether removed the second product (OCH3, 24%). This showed that this was a true "ether-soluble" fraction, but it was not found possible to isolate the pure methanol lignin (OCH3, 21.6%) by this process. The two substances can be separated either by solvent extraction or, as now shown, by use of 8–10% sodium hydroxide. Methylation of methanol lignin with dimethyl sulphate and alkali gives rise to the formation of new hydroxyl groups, the extent of the changes increasing markedly with rise in temperature of methylation and with increase in concentration of alkali used.A methanol lignin (OCH3, 22.3%) on repeated methylation yields a methylated lignin containing 37.2% methoxyl. Degradation during methylation is restricted by the use of acetone as solvent and only a slight excess of alkali (5–10%) at 20 °C. The results indicate the necessity for caution in the interpretation of data based on methylation experiments involving the use of alkali, and point to the presence of heterocyclic oxygen rings, non-furane in type, as part of the lignin structure. When refluxed for 48 hr. with 65 % aqueous methyl alcohol containing 9% sulphuric acid, ether-insoluble methanol lignin (OCH3, 22.3%) yielded a product with methoxyl content 21.3% which decreased to 20.9% when the product was treated for a further 52 hr.

ISSN:1923-4287    

DOI:10.1139/cjr37b-004

出版商:NRC Research Press    

年代:1937

数据来源: NRC

摘要:

p-Methyl-,p-chloro- andp-bromodiphenylsuccinamides have been prepared, and their behavior toward alkaline sodium hypobromite under the conditions of the Hofmann reaction has been investigated. The three amides yield as principal productsp-methyl-,p-chloro- andp-bromo-diphenylacetic acids. It may be concluded that this behavior is characteristic of αα′-diarylsuccinamides.

ISSN:1923-4287    

DOI:10.1139/cjr37b-005

出版商:NRC Research Press    

年代:1937

数据来源: NRC