摘要:

Profiles and areas of interfaces subjected to interfacial tension measurements by the du Noüy ring method, were calculated with the aid of a digital computer. The computations were based on a solution of a set of two simultaneous, first order, ordinary differential equations. Area corrections amounted to from 5 to 17% of the total area calculated on the assumption of planar contact. These corrections permit more precise evaluation of the molecular area of monolayers spread at such interfaces. Two interfaces, viz. benzene–water and hexane–water, were taken as examples. Profiles of curves around the rings were also determined experimentally by means of an electrical contact micromanipulator method. Theoretically computed and measured profiles show very good agreement.

ISSN:0008-4042    

DOI:10.1139/v59-284

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Conversion by hydrochloric acid in 2-propanol of 5,7:3′,4′-tetramethoxyflavan-3,4-diol (I; R = OMe) into cyanidin chloride 5,7:3′,4′-tetramethyl ether is examined. The diol is wholly changed into the anthocyanidin. The over-all reaction mechanism must therefore be oxidative, since the alternative of disproportionation is excluded. Fading of this anthocyanidin in solution is studied. Attempts to synthesize flavan-3-one derivatives are briefly described.

ISSN:0008-4042    

DOI:10.1139/v59-285

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

5-O-Methyl-L-arabinose is thought to occur in the hydrolysis products of methylated wheat bran hemicellulose. This sugar has now been synthesized from ethyl 2,3-di-O-acetyl-5-O-trityl-α-L-arabinoside by detritylation, methylation, and hydrolysis. The free sugar was obtained as a sirup and was characterized by periodate oxidation together with the preparation of a crystalline osazone and a crystalline lactone.

ISSN:0008-4042    

DOI:10.1139/v59-286

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

The transference numbers, equivalent conductances, densities, and viscosities of aqueous solutions of silver nitrate and of silver perchlorate have been determined from a concentration of 0.1 Mup to 7.6 M, for silver nitrate, and up to 5.6 Mfor silver perchlorate. In both cases the cation transference number increases considerably with increasing concentration. Certain anomalies in the results for silver perchlorate raise the possibility of complex ion formation here. Similar anomalies appear in the behavior of equivalent conductance with respect to concentration.The results of the conductance measurements have been compared with the values calculated from the equations of Wishaw and Stokes and of Falkenhagen and Leist.

ISSN:0008-4042    

DOI:10.1139/v59-287

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

The "trianhydrosucrose" obtained on treatment of amorphous "sucrose tritosylate" with sodium methoxide was found to be 1′,2;3,6;3′,6′-trianhydrosucrose.

ISSN:0008-4042    

DOI:10.1139/v59-288

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

A new pigment, volucrisporin, has been isolated from shaken cultures of the HyphomyceteVolucrisporaaurantiacaHaskins, and characterized as 2,5-(m-hydroxyphenyl)-1,4-benzoquinone. The structure has been confirmed by synthesis of the dimethyl ether.

ISSN:0008-4042    

DOI:10.1139/v59-289

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

The ultraviolet absorption spectra of a series of fluorobenzenes are determined. It is found that as a first approximation a fluoro substituent does not appreciably affect the benzenoid absorption. The spectra are discussed on the assumption that the mesomeric effect of the fluorine atom is small.

ISSN:0008-4042    

DOI:10.1139/v59-290

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

The properties of silica gels sensitized by methyl orange and its homologues were critically examined in order to decide between the alternative hypotheses of a lock and key mechanism and an association mechanism to explain the enhancement of adsorption. Evidence appears to favor an association mechanism in which the unextractable dye particles act as centers to attract their own kind more strongly than one of their homologues. Nitrogen area measurements show that less than 0.5% of the gel surface area is used in adsorbing dye molecules. The dye series from methyl to butyl orange have a very sharp increase in solubility from ethyl to propyl when dissolved in 5% aqueous acetic acid solution (pH = 2.3).

ISSN:0008-4042    

DOI:10.1139/v59-291

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

The structures of isolycoctonine and hydroxylycoctonine salts have been shown to be VII and X respectively. These structures and the δ-lactone character of the products of lead tetraacetate cleavage of hydroxylycoctonam are in harmony with structure XI for hydroxylycoctonine.

ISSN:0008-4042    

DOI:10.1139/v59-292

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Certain types of unsaturated lactones exhibit two bands in the region of the spectrum associated with the C=O stretching vibrational mode. This is observed both in the infrared and Raman spectra.The infrared spectra of 23 simple saturated and unsaturated lactones have been examined in an attempt to determine the structural features with which this carbonyl band splitting is associated. It appears to be common to most unsaturated five- and six-membered ring lactones in which the double bond is conjugated with the carbonyl group, though one well-established exception has been observed. The relative intensities of the two bands are extremely sensitive to changes in the polarity of the solvent; they also vary reversibly with temperature but are independent of concentration.The splitting of the C=O stretching band is attributed to an intramolecular vibrational effect similar to that which occurs in cyclopentanone and in certain Δ2-cyclopentenone derivatives. Its possible dependence on Fermi resonance with the overtone of a lower lying fundamental vibration is discussed.Similar effects occur in other types of carbonyl compounds, such as benzoyl chloride and cyclic five-membered ring anhydrides, and care is needed to distinguish carbonyl band splitting of this kind from that associated with equilibria between conformational isomers.

ISSN:0008-4042    

DOI:10.1139/v59-293

出版商:NRC Research Press    

年代:1959

数据来源: NRC