Automation of the gas analysis of14C-labelled compounds utilizing a piston-type counter tube

In this paper an automatic apparatus designed for the radioactivity measurement of¹⁴C-labelled organic compounds in the gaseous phase is described. The labelled organic compounds are combusted in a mixture of argon and oxygen. After combustion the oxygen content of the gas is eliminated by passing it through a copper packing. The water and heteroelements present are also removed and the radioactive carbon dioxide gas is swept by argon carrier gas into a piston-type counter tube. In the counter tube the piston forming a dividing wall moves forward in accordance with the rate of combustion and sweeping, and thus sucks the gases leaving the combustion tube into the effective tube volume. The anode wire is carried by a reel located in the piston and a spring device ensures its stretched state. At the end of the sweeping period methane is fed into the counter tube and the activity of the argon—methane—carbon dioxide mixture is measured in the limited proportional region. Manual and automatic operation is possible. The piston-type counter tube provides possibility for strandardization by means of extrapolation and for measurement of absolute activities.     

Determination of the spin sublevel origin of radiative and non-radiative decay routes of phosphorescing benzene derived from precision lifetime measurements

The increase in the phosphorescence lifetime as temperature is lowered has been quantitatively determined in the 2–30 K range. Applying the Boltzmann population expression yields the information that virtually none of the radiative decay originates from the lowest spin sublevel (A_2g).     

Zum thermischen Verhalten von Li3MnO4. II [1, 2]. Über α- und β- Li2MnO3

Thermal Behaviour of Li₃MnO₄. II. α- and β-Li₂MnO₃ By thermal decomposition of Li₃MnO₄ we obtained two new forms of Li₂MnO₃: α-Li₂MnO₃ crystallizes due to Guinier-Simon photographs cubic face-centered with a = 4.09₂ Å, β-Li₂MnO₃ hexagonal with a = 4,93, c = 14.24 Å, c/a = 2.89. α-Li₂MnO₃ is paramagnetic with μ = 3,82 B.M. Below the Neel temperature (≈? 50 K) β-Li₂MnO₃ is antiferromagnetic. Effective Coordination Numbers, ECoN, are calculated and discussed.     

A study of the process of lignification of one-year willow wood

Conclusions 1. The content of lignin in the wood ofSalix viminalis andSalix acutifolia increases with the growth of the shoots during shortened days and also in drier climatic periods.2. The monosaccharides, glucose, fructose, and arabinose take part in the synthesis of the lignin of young wood ofSalix viminalis andSalix acutifolia. The formation of lignin of one-year willow wood takes place from May to January (with a maximum in June–July). The content of methoxyl groups in it gradually rises.Khimiya Prirodnykh Soedinenii, Vol. 5, No. 6, pp. 546–550, 1969     

Einige Übergangsmetallkomplexe von Diäthylestern der 1-Cyano-2-Oxo-Propanphosphonsäure (1-CDÄPA) und der Äthoxycarbonylmethanphosphonsäure (CMPD)

Some Transition Metal Complexes of Diethyl Esters of 1-Cyano-2-oxo-propane-phosphonic Acid and Ethoxycarbonylmethane-phosphonic Acid By means of metal exchange cobalt(II), nickel(II), and chromium(III) complexes of diethyl esters of 1-cyano-2-oxo-propane-phosphonic acid (1-CDEPA) and ethoxycarbonylmethanephosphonic acid (CMPD) were obtained from their corresponding potassium salts and halides of transition metals. The stable chelatic structure of these complexes was established by means of i.r. spectra and the configuration on the basis of the electron spectra and their magnetic moments.     

Free energies of electron ejection of aromatic hydrocarbon negative ions in ethers at room temperature

The free energies of electron ejection of some aromatic hydrocarbon mono- and di-negative ions in DME and 2-MTHF at room temperature are estimated from existing experimental data. The formation of free solvated electrons requires about the same amount of free energy whether the negative ion is present as a loosely bound or a tightly bound associate with the sodium counter ion. When the ejected electrons are trapped by a solvent cavity in the vicinity of the sodium ion the reaction requires appreciably less energy for the tightly bound than for the loosely bound associates. The data are essential for the study of the photo-ionization of aromatic hydrocarbon negative ions in ethers.     

Copolymerization characteristics of S-vinyl-O-tert-butylthiocarbonate

Poly-S-vinyl-O-tert-butylthiocarbonate is an excellent precursor to poly(vinyl mercaptan) because the tert-butyloxycarbonyl blocking group can be removed by either acid hydrolysis or thermolysis under conditions which minimize the oxidation of the liberated mercaptan to disulfide. Dilatometric studies of the homopolymerization of S-vinyl-O-tert-butylthiocarbonate demonstrated that the polymerization rate was directly proportional to the concentration of free-radical initiator; no thermal initiation was observed. The molecular weight of the homopolymers and copolymers ranged from 30,000 to 50,000 (GPC). Copolymerization of S-vinyl-O-tert-butylthiocarbonate (M₂) with styrene, (r₁ = 3.0, r₂ = 0.2), methyl methacrylate (r₁ = 1.40, r₂ = 0.17) and vinyl acetate (r₁ = 0.04, r₂ = 11.0) indicated that a sulfur atom adjacent to the vinyl group increases the resonance stability (Q₂ = 0.5) and the electron density (e₂ = ?1.4) of the double bond and the corresponding radical. Water-soluble copolymers could be prépared by incorporating either N-vinylpyrrolidone (r₁ = 0.12, r₂ = 3.94) or N-isopropylacrylamide (r₁ = 1.17, r₂ = 0.3) with M₂. The water solubility of the copolymers decreased markedly when the tert-butyloxycarbonyl group was removed. Copolymers of M₂ with N-vinyl-O-tert-butylcarbamate (r₁ = 0.13, r₂ = 5.10) were utilized to prepare crosslinked poly(vinyl amine–vinyl mercaptan); the crosslinking resulted from urea linkages formed during thermolysis of the copolymer.     

Activation a l'aide de polyamines tertiaires de la polymerisation anionique du styrene amorcee par les composes organolithiens

A study of the influence of tertiary polyamines on the reactivity of polystyryllithium ion-pairs in hydrocarbon solvents has been performed. The stability of active centres has been studied and allows the processing of kinetic data as for living systems. Rate constants of propagation have been measured in terms of the structure of the polyamine, its relative concentration, the concentration in organometallic species, the temperature and the nature of solvent; in all cases, they are absolute rate constants. The values show the important effect of the number of nitrogen atoms in the additive and especially the strong influence of its geometry: the cyclic polyamine studied leads to an activation of the reaction much greater than that of the corresponding linear substance. These results may be interpreted in terms of different solvation states for the polystyryllithium ion-pairs.     

Some investigations on the photostabilization of polypropylene

The effect of substituted hydroxybenzophenone, benzotriazole and organic metal complexes on the photooxidation of PP films has been studied. It has been established that NiDBTC added in 1.0 wt. % is the most effective photostabilizer.While in the case of other stabilizers there is a slight increase in the Co content even during the induction period, with the application of NiDBTC practically no oxidation can be observed before the stabilizer completely disappears. This means that NiDBTC inhibits the photooxidation of the polymer even in low concentration.

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