摘要:

The exchange reactions between silver and its ions in solution have been investigated by the use of radioactive tracers. Silver of highest purity was cleaned carefully and immersed into a radioactive silver nitrate solution. The course of the early absorption process and subsequent diffusion of the ions into the interior of the metal was followed in detail, and the diffusion coefficient at room temperature was calculated. The penetration depth was determined by controlled electropolishing of the metal, and the reverse movement of active ions from the metal into inactive solutions was also observed.

ISSN:0008-4042    

DOI:10.1139/v61-251

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

The usefulness of Whatman seed-test and No. 17 papers has been examined for purification and recovery on a preparative scale of the toxin present in residues of low toxicity from the Schantz alumina chromatographic method for purification of clam poison. A method was developed to minimize introduction of impurities from the papers into fractions recovered after chromatography whent-butanol: acetic acid: water (2:1:1) was used as developer. Seed-test paper gave better separation of the toxin from other components of the residues than did No. 17 paper. Residues of bio-assay as low as 300 MU/mg were found to be capable of enrichment by the method. On a scale of 500 mg per 18 × 22-in. sheet of pretreated seed-test paper, using residues of toxicity 1400 MU/mg, a 67% recovery of toxin enriched fourfold to 5800 MU/mg was achieved in four passes. Increased loading of the paper led to a decrease in both enrichment per pass and over-all recovery of toxin. The paper chromatographic properties, toxicity, and infrared spectrum of the recovered poison agree with those reported by Schantz and co-workers for pure clam poison dihydrochloride, but the specific rotation is lower by 25%. Four possible alternative explanations for the observed anomalous rotation are discussed.

ISSN:0008-4042    

DOI:10.1139/v61-252

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

An apparatus is described for fractionating large quantities (400 g) of polythene into five roughly equal fractions using a fractional precipitation technique. Application of this method of fractionation to a linear polythene has shown that the width of the molecular-weight distribution of the successive fractions decreases as the fractionation proceeds. Consequently, the initial high-molecular-weight fractions require refractionation to produce equally narrow distributions in them as are found in later fractions. Good agreement is obtained with the experimentally determined values of the number-average and weight-average molecular weight for the parent polymer when the measured values ofMnandMwfor each fraction are used to calculate the values for the parent. The differential molecular-weight distribution function of the parent polymer was calculated on a Bendix G-15 computer from the data for the fractions by using the weight, number-average and weight-average molecular weight, measured for each fraction in conjunction with an assumed log-normal or negative binomial molecular-weight distribution function in each fraction.

ISSN:0008-4042    

DOI:10.1139/v61-253

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

Gas–liquid partition chromatography has been used to separate the fully acetylated derivatives of tetritols, pentitols, hexitols, heptitols, octitols, and anomeric glycoses.

ISSN:0008-4042    

DOI:10.1139/v61-254

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

The Hg(3P1)-photosensitized reaction of methyl acetate at micron pressures in the presence of 8 mm of helium has been examined in a flow system by mass spectrometry. At 55 °C the primary dissociation is mainly into acetyl and methoxy radicals. An alternative dissociation into CO2and two CH3radicals occurs with a frequency of about one fifth of the principal reaction. A small amount of COOCH3radical is also formed. No CH3CO2radicals could be found. Since the yield of H2is less than 2% of the methyl acetate decomposed, a primary dissociation to give H atoms and CH3COOCH2or CH2COOCH3radicals is quite small.

ISSN:0008-4042    

DOI:10.1139/v61-255

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

The distillable esters of heated linseed oil contain a fraction, designated NAFD, which fails to form an adduct with urea. NAFD itself has now been separated into three fractions by gas-liquid partition chromatography. The chemical structure of these component esters was investigated by means of their infrared spectra and by analysis of the products obtained on oxidation of the esters with periodate–permanganate. It is concluded that all the components have the same carbon skeleton, namely, 1-propyl-2-alkenecarboxycyclohexene, but differ in the position of the double bond in the side chain.

ISSN:0008-4042    

DOI:10.1139/v61-256

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

Differential thermal analysis was used to study the thermal breakdown of balsam fir and its components in air from 50° to 420 °C. In this range, the thermogram of balsam fir is simply a composite of the individual thermograms of the components of the wood, with little, if any, interaction between the components.

ISSN:0008-4042    

DOI:10.1139/v61-257

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

It has been confirmed that the apparent rate constant for the reaction between methyl radicals, produced by the photolysis of deuterated acetone, and isobutane increases with decreasing isobutane pressure. An explanation is proposed to account for this observation suggesting that the production of methane by disproportionation between methyl andt-butyl radicals was not negligible as has been assumed previously.

ISSN:0008-4042    

DOI:10.1139/v61-258

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

Here are reported the design and calibration of a new inexpensive free-flow electroviscometer for rapid and accurate measurement of the viscosity coefficients for conducting and non-conducting solutions. Flow times of 30 seconds are easily reproduced to within 0.02 second.

ISSN:0008-4042    

DOI:10.1139/v61-259

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

Estimates of the extent of the hydrogen exchange reaction between cellulose and water vapor determined by an improved method using tritiated water and by the use of heavy water were usually in good agreement. With certain samples, surface roughness had a small effect upon the measurement of tritium radioactivity in cellulose.The accessibility or limiting extent of the exchange increased slightly with relative humidity in the range 20 to 100% and was attributed to the reduction of crystalline order reported recently in similar experiments.In contrast to cellulose whose accessibility corresponds approximately to the amorphous fraction, a partially crystalline amylose was 100% accessible while an amorphous xylan was 52% accessible, indicating that in these substances the accessibility and the fraction of amorphous material are not identical.

ISSN:0008-4042    

DOI:10.1139/v61-260

出版商:NRC Research Press    

年代:1961

数据来源: NRC