摘要:

AbstractV‐T measurements carried out on the ethylene‐naphthalene system at constant composition are described. The measurements also provide data on the saturation volumes of solutions of naphthalene in supercritical ethyl

ISSN:0165-0513    

DOI:10.1002/recl.19610800702

出版商:WILEY‐VCH Verlag    

年代:1961

数据来源: WILEY

摘要:

AbstractProjections of the V‐T‐x space model of the ethylene‐naphthalene system are derived from the observations recorded in the preceding publication1together with some supplementary measurements. The value for the critical volume at the second critical endpoint is found to be 77.0 ml/mol.A number of T‐x and V‐x sections through the space model are derived from the same obs

ISSN:0165-0513    

DOI:10.1002/recl.19610800703

出版商:WILEY‐VCH Verlag    

年代:1961

数据来源: WILEY

摘要:

AbstractIn the system mercury/aqueous Na‐decane sulfonate/hydrogen contact angles are obtained by calculation from the three interfacial tensions, and by direct measurement.Electrocapillary measurements are described, by which the influence of the surface charge (surface potential) on the adsorption of Nadecane sulfonate at the mercury/solution interface is studied.Using the sessile drop method, equilibrium surface tension data are obtained for all three interfaces, and for different values of the surface potential of the mercury.Calculated and measured contact angles are in good agreement over a range of concentrations of Na‐decane sulfonate.The problem of the thickness of the solution layer at the mercury/gas interface is discus

ISSN:0165-0513    

DOI:10.1002/recl.19610800704

出版商:WILEY‐VCH Verlag    

年代:1961

数据来源: WILEY

摘要:

AbstractThe paraffine oil mull spectra of NaNO2, KNO2and AgNO2are reported. The 836 cm−1band in the spectrum of KNO2is assigned to a vibration of the NO3−ion which always occurs as an impurity in KNO2. Evidence is presented for the occurrence of double decomposition during m ulling operati

ISSN:0165-0513    

DOI:10.1002/recl.19610800705

出版商:WILEY‐VCH Verlag    

年代:1961

数据来源: WILEY

摘要:

AbstractThe dissociation constants of 4‐aminoazobenzene‐4′‐sulphonic acid, 4‐(methylamino)azobenzene‐4′‐sulphonic acid, 4‐(phenylamino)‐azobenzene‐4′‐sulphonic acid, 4‐(dimethylamino)azobenzene‐4′‐sulphonic acid andp‐nitrophenol were determined in water and in several mixtures of methanol and water at 25°. The influence of the percentage of methanol on the dissociation constant differs greatly for the various indicators, even for indicators of the same charge type.From this it follows that Hammett's acidity function H0for solutions in mixtures of methanol and water depends on the indicator used for determining H0. Thus, for solutions in mixtures of methanol and water and presumably also in mixtures of water and other non‐electrolytes, H0is not a usef

ISSN:0165-0513    

DOI:10.1002/recl.19610800706

出版商:WILEY‐VCH Verlag    

年代:1961

数据来源: WILEY

摘要:

AbstractThe thermal decarboxylation of alkali trichloroacetates in aprotic solvents in the presence of olefins has been investigated. The isolation of dichlorocyclopropanes in good yields demonstrates the formation of CCl2as an intermediate. By this method, the reaction of base‐sensitive acceptors such as allylchloride with CCl2may be successfully accomplished, since it proceeds under essentially neutral conditions. Vinyl acetate gave, in addition to the cyclopropane derivative, 1‐trichloromethylethyl acet

ISSN:0165-0513    

DOI:10.1002/recl.19610800707

出版商:WILEY‐VCH Verlag    

年代:1961

数据来源: WILEY

摘要:

AbstractThis article gives the experimental results of UV measurements made on an extensive series ofunsymmetricallysubstituted methylbenzophenones in solution (ethanol andiso‐octane). The results obtained are compared with our previously published UV measurements on symmetrically substituted benzophenones and correlated with literature data on the UV absorption of acetophenones.From this investigation it appears that for the benzophenone series the oscillator strength f is an additive quantity, a fact which is very useful in comparing the various ketones with one another.The comparison with acetophenone ‐ in which not only f, but also the wavelength of the conjugative absorption band plays a part ‐ supplied useful information on the position of the phenyl rings relative to the C

ISSN:0165-0513    

DOI:10.1002/recl.19610800708

出版商:WILEY‐VCH Verlag    

年代:1961

数据来源: WILEY

摘要:

AbstractThis article gives the experimental results of UV measurements made on a number of benzophenones with ethyl,isopropyl andtert.butyl groups as substituents. The results are compared with the previously published data on the corresponding methyl‐substituted benzophenones1,2,3,4. Our investigation showed that there is no significant difference between the effects of introduction ofortho‐methyl,ortho‐ethyl orortho‐isopropyl groups into a benzophenone. With atert.‐butyl group, however, the result is somewhat different: in this case a steric effect is observed on the electronic spectra, which is only slightly smaller than that encountered in 2,6‐dimethylbenzophenone. When plotting the λCdifferences betweenmeta/para‐substituted derivatives and the unsubstituted benzophenone against theHammettσ‐values the result is a straight line, theHammettσ‐constant being −0.061 for ethanol and −0.05

ISSN:0165-0513    

DOI:10.1002/recl.19610800709

出版商:WILEY‐VCH Verlag    

年代:1961

数据来源: WILEY

摘要:

AbstractSyntheses of a series of 4,4′‐dimethoxystilbenes, substituted with methyl or ethyl groups inorthoand α‐positions, including the new compounds 2,2′,6,6′‐tetramethyl‐ ; α,2‐dimethyl‐ ; α,2′‐dimethyl‐ ; α,2,2′‐trimethyl‐ and α,α′,2‐trimethyl‐4,4′‐dimethoxystilbene, are described.In most cases demethylation with pyridine hydrochloride gave the 4,4′‐dihydroxystilbenes in good yield.Attempts to synthesize 2,2′,6,6′,α,α′‐hexamethyl‐4,4′‐dimethoxystilbene in reasonable amount were unsuccessful.The infrared absorption spectra of the dimethoxystilbenes were measured. An increase in the out‐of‐plane Cα‐H frequency was observed in the series: 4,4′‐dimethoxystilbene, 2,2′‐dimethyl‐, 2,2′‐diethyl‐, 2,2′,6,6′‐tetramethyl‐4,4′‐dimethoxystilbene. This increase, seemingly, parallels the increase in steric inhibition of molecular coplanarity, the same sequence being observed in the positions of the ultraviolet N → V absorption bands.For the α‐substituted stilbenes, the Cα‐H frequencies are located in the same region as the absorptions due to the substituted benzene rings and conclusions are uncertain.The molecular refractions of the compounds, corrected for the alkyl substituents, decrease with increasing steric hindrance. For most compounds the decrements in molecular refra

ISSN:0165-0513    

DOI:10.1002/recl.19610800710

出版商:WILEY‐VCH Verlag    

年代:1961

数据来源: WILEY

摘要:

AbstractFrom a quantity of ethyl mandelate there separated, after prolonged storage, a crystalline compound, which was found to consist of mandelic acid and ethyl mandelate in a 1 : 1 ratio. This product can also be preparedin situby mixing equivalent amounts of mandelic acid and ethyl mandelate, the crystalline product separating with generation of heat. This phenomenon did not occur when some other mandelic esters were investigated.

ISSN:0165-0513    

DOI:10.1002/recl.19610800711

出版商:WILEY‐VCH Verlag    

年代:1961

数据来源: WILEY