摘要:

The adsorption of the sodium soaps of lauric, myristic, palmitic, stearic, and oleic acids from aqueous solutions by a carbon black has been measured. The adsorption appears to be a combination of two more or less independent processes: (a) adsorption of neutral soap, and (b) adsorption of fatty acid resulting from hydrolysis. The adsorption of both the fatty acid and alkali components of the soaps studied is in agreement with the Freundlich adsorption equation over the concentration range investigated, the extent of adsorption increasing with increasing chain length of the saturated soaps examined. In every case there is a greater adsorption of fatty acid than of alkali, but this difference becomes greater with increasing chain length of the soap. Increase in temperature causes a slight decrease in adsorption, but the effect is small. On the basis of its adsorptive behavior, sodium oleate appears to have an effective chain length of about 15 carbon atoms. Excess of fatty acid in the initial soap solution results in an increased adsorption of total fatty acid, but does not influence the adsorption of neutral soap; on the other hand, excess of alkali in the initial solution not only results in an increased adsorption of total alkali, but also leads to a decrease in the adsorption of fatty acid and neutral soap. This decrease in adsorption is attributed to suppression of hydrolysis, but even with 100% excess alkali, where hydrolysis must be almost completely suppressed, there is still an appreciable adsorption of fatty acid which must be adsorbed in the form of neutral soap. The adsorbed material corresponds to an acid soap of variable composition, the ratio of excess acid to neutral soap depending on the composition of the initial solution, the temperature, and the particular soap used. The adsorption of soap from 95% alcohol solution and from absolute alcohol solution is essentially the same, both being considerably lower than the adsorption of the same soap from aqueous solution. In spite of the fact that hydrolysis of soap does not occur in alcoholic solution, the fatty acid and alkaline components are not adsorbed in equivalent amounts, and it is suggested that, in this case, splitting of the soap is brought about by alcoholysis, followed by preferential adsorption of one of the reaction products.

ISSN:1923-4287    

DOI:10.1139/cjr49f-018

出版商:NRC Research Press    

年代:1949

数据来源: NRC

摘要:

In the analysis of wheat, oats, and barley for thiamine and riboflavin by three collaborating laboratories an attempt was made to reduce interlaboratory differences to a minimum by the establishment of a standardized procedure. The thiochrome and fluorometric methods were used for the thiamine and riboflavin determinations respectively. It was apparent that even after steps had been taken to standardize the assay procedures, small but consistent and significant interlaboratory errors existed. Calculations indicate that differences of the order of 10 to 12% in mean assay values were necessary before samples could be considered different with respect to their thiamine or riboflavin content.

ISSN:1923-4287    

DOI:10.1139/cjr49f-019

出版商:NRC Research Press    

年代:1949

数据来源: NRC

摘要:

In this paper are described the construction and operation of a pilot plant in which whole wheat mashes were successfully fermented byAerobacillus polymyxa. A yield of 8.9 lb. oflevo-2,3-butanedio1 and 5.9 lb. of ethanol per bushel of wheat was obtained, which is a fermentation efficiency of 90%. The best fermentations were obtained at 32 °C. using a 15% mash buffered with calcium carbonate. Agitation increased the fermentation efficiency at 96 hr. but decreased the diol-to-ethanol ratio. Reduced pressure did not change the efficiency but markedly reduced the ratio of diol to ethanol. Aeration had little effect. The presence of contamination organisms was highly detrimental and it was necessary to sterilize the mash, vessels, and piping. Although a backstocking technique could be practised in the preparation of inoculum, frequent recourse to stock cultures or improved strains was found advisable for maintenance of high yields.

ISSN:1923-4287    

DOI:10.1139/cjr49f-020

出版商:NRC Research Press    

年代:1949

数据来源: NRC

摘要:

The engine experiments of this Part are a sequel to those of Part VII showing that enrichment of a pentane–air mixture accelerates oxidation at end gas temperatures to the antiknock substances, steam, and the carbon oxides. The corresponding antiknock effect in an engine is increased by cooling if enrichment of the mixture leads to an increase in the proportion of the fuel admitted to the engine as liquid. The engine experiments were therefore made using two fuels,n-pentane and a commercial fuel "S", containing high boiling point constituents. The pentane could be vaporized prior to admission to the engine and the antiknock effect due to cooling eliminated. Thus, two concurrent antiknock effects were obtained on enriching the fuel–air mixture—one due to cooling, if the fuel were admitted to the engine in part as liquid, and the other to the consequent increase in the velocity of the heterogeneous oxidation reaction in the end gas. It was also shown by the experiments of Part VII that the oxidation of rich mixtures at end gas temperatures, to steam and carbon dioxide, was greatly accelerated when iron carbonyl was added to the fuel. Similarly, the engine experiments of this Part show that the antiknock effect of enriching the fuel–air mixture is greatly enhanced when iron carbonyl is added to the fuel.

ISSN:1923-4287    

DOI:10.1139/cjr49f-021

出版商:NRC Research Press    

年代:1949

数据来源: NRC

摘要:

Many factors, both inherent and environmental, affect the linamarin content of flax (its cyanogenetic principle). Redwing variety contains considerably more potential cyanide than does Royal. Flax, maintained at a high moisture level throughout the growth season, contains significantly less linamarin than that grown with access to less soil moisture. Frost, mechanical injury, and drought all affect the cyanogenetic content of flax adversely, the effect of the first being very great. Flax grown at the higher moisture level was more affected by these conditions than was flax grown at the lower moisture level. The recovery of cyanide from the glycoside by simultaneous enzymatic hydrolysis and aeration, and its estimation by the alkaline silver nitrate method, is an effective laboratory means of assessing the cyanogenetic content of flax. Although acetone, one of the decomposition products of linamarin, normally reacts with the alkaline picrate reagent, picrate under certain conditions may be adapted to the roughly quantitative estimation of cyanide by test paper in the field.

ISSN:1923-4287    

DOI:10.1139/cjr49f-022

出版商:NRC Research Press    

年代:1949

数据来源: NRC