摘要:

AbstractTenL‐α‐lecithins have been prepared by acylation ofL‐α‐glyceryl‐phosphorylcholine. Solubilities, RF‐values and other physical data are reported ofL‐α‐[diacetyl]‐lecithin,L‐α‐[dibutyryl]‐lecithin,L‐α‐[diheptanoyl]‐lecithin,L‐α‐[didecanoyl]‐lecithin,L‐α‐[di‐10‐methyl‐undecanoyl]‐lecithin,L‐α‐[dipentadecanoyl]‐lecithin,L‐α‐[dioctadecanoyl]‐le

ISSN:0165-0513    

DOI:10.1002/recl.19600790702

出版商:WILEY‐VCH Verlag    

年代:1960

数据来源: WILEY

摘要:

Abstract1) A colorimetric method has been elaborated for the determination of amyloids in plant seeds, based on the blue colour of the iodine complex in concentrated sodium sulphate solution.2) Details of the method are given and its possibilities and limitations are outlined.3) Three procedures for removing interfering starch are recommended.

ISSN:0165-0513    

DOI:10.1002/recl.19600790703

出版商:WILEY‐VCH Verlag    

年代:1960

数据来源: WILEY

摘要:

AbstractA method of degradation of toluene‐14C is described which makes it possible to determine the specific activity of each of the ring carbon atom

ISSN:0165-0513    

DOI:10.1002/recl.19600790704

出版商:WILEY‐VCH Verlag    

年代:1960

数据来源: WILEY

摘要:

AbstractPhthaloyl amino acids can be synthesized from N‐carboethoxy phthalimide and amino acid salts under very mild conditions in water. The preparation of 11 of these phthaloyl derivatives is described, some of which are new. Up to the present the method has only failed with tryptophane. Retention of the optical configuration during the reaction is show

ISSN:0165-0513    

DOI:10.1002/recl.19600790705

出版商:WILEY‐VCH Verlag    

年代:1960

数据来源: WILEY

摘要:

AbstractIt has been shown that pH* values, determined by the electrometric method in solvents other than water, can be interpreted as ‐logmHγ*Hif the pH meter is standardized by means of a standard solution in the same solvent. The pH* of standard solutions in methanol and methanol‐water mixtures can be determined by application of the same method as has been used by the National Bureau of Standards for the measurement of the pH of standard solutions in water.The errors that may occur when the method of the N.B.S. is applied to standard solutions in solvents other than water have been discussed. In order to correct these errors we calculated, by the method ofFuoss and Onsager, the values ofKand å for NaCl, KCl, KBr and KI in methanol, from literature data on the conductivity. The conductivity of solutions of NaBr and LiCl cannot be described satisfactorily by the equation ofFuoss and On

ISSN:0165-0513    

DOI:10.1002/recl.19600790706

出版商:WILEY‐VCH Verlag    

年代:1960

数据来源: WILEY

摘要:

AbstractBy application of a method which was developed in Part I of this series the pH* of an oxalate and a succinate buffer in water, methanol‐water mixtures and methanol and that of a salicylate buffer in methanol was measured. The pH* in methanol was measured by application of both silver chloride and silver bromide electrodes: the values obtained agreed closel

ISSN:0165-0513    

DOI:10.1002/recl.19600790707

出版商:WILEY‐VCH Verlag    

年代:1960

数据来源: WILEY

摘要:

AbstractThe determination of the liquid‐junction potential at the interface of an oxalate and a succinate buffer solution of known pH* in water, methanol or a methanol‐water mixture and a saturated KCl solution in water at 25° is described. When the pH* of such a solution is measured by means of a pH meter standardized by an aqueous standard solution, this liquid‐junction potential causes an error of over 2 pH* when the methanol content of the solution i

ISSN:0165-0513    

DOI:10.1002/recl.19600790708

出版商:WILEY‐VCH Verlag    

年代:1960

数据来源: WILEY

摘要:

AbstractThe dissociation constants of some primary aliphatic amines were measured in water and in methanol‐water mixtures at 25°. These dissociation constants (K* =a*Ha*B/a*HB) show a maximum at 60‐80% methanol. This maximum is ascribed to the unequal influence of the methanol content of the solvent on γ0,Hand

ISSN:0165-0513    

DOI:10.1002/recl.19600790709

出版商:WILEY‐VCH Verlag    

年代:1960

数据来源: WILEY

摘要:

AbstractA new type of hydrogen‐deuterium exchange reaction in acid media, viz. the exchange of hydrogen atoms of the t‐butyl group, substituted in benzene rings, has been found. The reaction is first‐order in the concentration of the hydrocarbon. There is no simple relation between the rate constant, k, and either the acidity function H0, or the concentration, ca, of the acid. Log k is, however, linearly related with (‐ H0+ log ca). The activation energy is 20.2 ± 0.3 kcal/mole.The results indicate that the exchange reaction of the t‐butyl group proceeds via an ionic intermediate in which the carbon‐carbon bond between the t‐butyl group and the aromatic ring is probably weakened. The rate‐determining step of the reaction is the formation of this intermediate.The exchange reaction seems to be closely related to isomerization and transalkylation reactions; the formation of the ionic intermediate may be a common step for all

ISSN:0165-0513    

DOI:10.1002/recl.19600790710

出版商:WILEY‐VCH Verlag    

年代:1960

数据来源: WILEY

摘要:

AbstractThis report deals with the results of a detailed investigation into the accuracy of a quantitative analysis of mixtures of lower fatty acids (C2‐C12) by means of paper chromatography.To this end, mixtures of 2, 3, 4 or 5 fatty acids were weighed‐in, and by means of the methods described in previous reports, converted into the anilides and subjected to paper chromatography. From the results the compositions of the fatty acid mixtures were calculated and compared with the actual compositions. The differences were statistically evaluated to a mean deviation and a standard deviation. The values clearly demonstrate the reliability of the method. The recovery of the fatty acids was 81‐88%.The values obtained do not differ appreciably from these obtained in the analysis of pure anilides (the latter investigation had a more limited scope). It may, therefore, be concluded that the limitations of the method are connected with the paper chromatography.No indications have been obtained that the analytical data are dependent on the percentage or on the Rf

ISSN:0165-0513    

DOI:10.1002/recl.19600790711

出版商:WILEY‐VCH Verlag    

年代:1960

数据来源: WILEY