Gas chromatographic analysis of estrogens. II

Summary A simple method is described for the introduction of samples to a gas Chromatograph by means of a septumless port. The reproducibility and accuracy of the method have been shown by the analysis of ng quantities of estrone, estradiol, and estriol as the heptafluorobutyrates with an electron capture detector.

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Zusammenfassung Die Einbringung von Proben in einen Gaschromatographen durch einen membranlosen Einspritzblock wurde beschrieben. Die Reproduzierbarkeit und Genauigkeit der so erhaltenen Ergebnisse wurde durch die Bestimmung von Nanogrammengen Östron, Östradiol und Östriol als Heptafluorobutyrate mit einem Elektroneneinfangdetektor erwiesen.

     

A regio- and stereoselective alpha-methylation of gamma,delta-epoxy-alpha,beta-unsaturated esters with a Me2Zn-CuCN reagent

A highly regio- and stereoselective alpha-methylation reaction of gamma,delta-epoxy-alpha,beta-unsaturated esters was achieved by using a Me2Zn-CuCN reagent.     

Determination of nickel in standard rocks and glasses by photon activation analysis with 30-MeV bremsstrahlung

The determination of nickel in various silicate rocks and glasses by photon activation analysis with a linear electron accelerator is described. Simultaneous irradiation of the sample and comparative standards produces the ⁵⁸Ni(γ, n)⁵⁷Ni reaction, and a post-irradiation chemical separation is used in conjunction with Ge(Li) γ-spectrometry. Nickel abundances for ten standard silicate rocks and two elementally doped glasses are presented and compared with the data previously published. The method is quite simple and gives good reproducible results for nickel down to sub-p.p.m. levels.     

Photo-induced cellulose radicals capable of initiating graft copolymerization

The decay behavior of cellulose radicals produced by photo-irradiation at room temperature and the characteristics of photo-irradiated cellulose samples to initiate graft copolymerization of methyl methacrylate (MMA) were investigated. ESR spectra of such untreated, swollen, oximated, and ferric ion-sensitized samples irradiated at room temperature were constructed mainly of a single absorption line with a line width of 20 to 22 gauss and a g value of 2.003, and it is surely conceivable that the radicals showing a singlet spectrum should agree with those of alkoxy end produced at either the C₁ or C₄ position of the glucose unit by the scission of glucosidic bonds. The decay of radicals was accelerated by contact of various solvents with the samples, the activity decreasing in the order, water ≈ methanol ? acetone > dioxane. On the other hand, the decay of radicals by vinyl monomers became smaller in the order, methacrylic acid > MMA ≈ styrene. Graft copolymerization of MMA by a photo-irradiated sample was effectively initiated with the use of a certain amount of water or methanol, but not with acetone and dioxane. As no initiation can occur with the unirradiated sample, it is concluded that the initiation of graft copolymerization on the photo-irradiated sample is attributable to cellulose radicals showing a singlet spectrum which are formed in photo-irradiation at room temperature.     

Cationic polymerization behavior of hydroxystyrenes

Solution polymerizations of o-, m- and p-hydroxystyrene with boron trifluoride etherate were investigated. The results of infrared and ultraviolet spectroscopic investigations of the polymers thus obtained indicate that p-hydroxystyrene polymer consisted mainly of the structure formed through the normal vinyl polymerization mechanism, whereas o- and m-hydroxystyrene polymers contained considerable portions of the structures due to the reaction of the vinyl group with the phenol nucleus. The rate of polymerization and the intrinsic viscosity of the polymer decreased in the order p-hydroxystyrene ? o-hydroxystyrene > m-hydroxystyrene. It was of interest that on the cationic polymerization only p-hydroxystyrene gave polymer of high molecular weight. Plausible polymerization mechanisms were considered. Solid-state polymerization of p-hydroxystyrene at solid carbon dioxide temperature with the use of boron trifluoride etherate was also investigated. Appreciable polymerization occurred only at fairly high catalyst concentrations.     

Dependence of phase behavior of some non-ionic surfactants at the air-water interface on micellization in the bulk

The temperature-dependent surface phase behavior of two sparingly soluble surfactants, namely, ethylene glycol n-dodecyl ether (EGDE) and ethylene glycol n-tetradecyl ether (EGTE), at the air-water interface was investigated by film balance and Brewster angle microscopy (BAM). A cusp point followed by a pronounced plateau region in the surface pressure-time (pi-t) adsorption isotherms of the amphiphiles measured by film balance indicates the first-order phase transition. Bright two-dimensional condensed phase domains in a dark background are observed by BAM just after the phase transition. In both cases the critical surface pressure necessary for the phase transition increases with increasing temperature. The domains are found to be circular up to 5 and 27 degrees C for EGDE and EGTE, respectively, above which they show a fingering pattern. Condensed domains are observed up to 23 and 37 degrees C for EGDE and EGTE, respectively. The surface properties of the amphiphiles are found to be markedly affected by their tendency to aggregate in the bulk as micelles. The CMC values of both the amphiphiles show a maximum at a definite temperature, T(max), that corresponds well to their respective maximum temperatures of domain formation. An increase in temperature beyond T(max) results in an increasing trend for the formation of micelles. Consequently the system suffers from a shortage of two-dimensional surface concentration of the molecules to attain the surface pressure necessary for phase transition. With increasing temperature, the enthalpy, DeltaH(m) degrees , and entropy, DeltaS(m) degrees , of micellization change from negative to positive in both cases. An enthalpy-entropy compensation effect is found to hold for both the amphiphiles over the entire temperature range. The thermodynamic quantities reveal that the increase in temperature is favorable for micellization when the temperature exceeds the corresponding T(max) of the amphiphiles.