Quaternary ammonium polyelectrolytes. IV. Addition reaction between poly(4-vinylpyridinium chloride) and electrophilic vinyl compounds

It was found that the addition reaction between poly(4-vinylpyridinium chloride) and electrophilic vinyl compounds, such as acrylic acid, acrylamide, methylacrylate, and acrylonitrile. leads to ammonium quaternary polymers with a transformation degree that depends oil the reactivity of vinyl compounds. The structure of addition compounds was established by using ¹H-NMR IR, and UV spectral methods. NMR-determined values of transformation degree indicate that the reactivity of vinyl compounds decreases as follows:      

Quaternary ammonium polyelectrolytes. III. Kinetic studies of amination of chloromethylated polystyrene with tertiary amines

The amination kinetics of benzyl chloride and chloromethylated polystyrene with three tertiary amines were studied: N-2-hydroxyethyl-dimethylamine, N,N-bis(2-hydroxyethyl)-methylamine, and triethylamine in N,N-dimethylformamide. The amination of chloromethylated polystyrene takes place with two reaction rate constants K₁ and K₂. K₂ is higher than K₁; hence there is a self-accelerating effect. This phenomenon is due to the influence of the positive electrostatic field of the macroion chain on amines that are nucleophilic reactants. The magnitude of the self-accelerating effect given by the K₂/K₁ ratio depends on the substituent volume of the nitrogen atom of the amine molecule.     

X-ray photoelectron and mössbauer spectroscopy studies of the valence state of transition metal ions in Co1–x Fe x Cr2O4 (x = 0.1, 0.2, 0.5) ceramics

The valence state of transition metal ions in the Co_1–x Fe _x Cr₂O₄ (x = 0.1, 0.2, 0.5) system has been investigated using X-ray photoelectron and Mössbauer spectroscopy. It has been shown that, in this system, there are Fe²⁺ and Fe³⁺ ions. The relative Fe³⁺/Fe²⁺ contents have been determined by fitting the experimental Fe 2p photoelectron spectra by a superposition of theoretical spectra of the Fe²⁺ and Fe³⁺ ions, as well as using Mössbauer spectroscopy.     

The tree property at the first and double successors of a singular

We show that given ω many supercompact cardinals and a weakly compact above them, there is a generic extension in which the tree property holds at the first and second successor of a strong limit singular cardinal.     

Zeeman relaxation of CaF in low-temperature collisions with helium

The collision-induced Zeeman relaxation rate for collisions of CaF X2Sigma(v(')=0) with 3He is measured to be Gamma(Z)=(7.7+5.4/-2.5)x10(-15) cm(3)/s at 2 K. This rate is a direct measurement of the influence of spin-rotation coupling on Zeeman relaxation in the first rotational level of CaF. The relationship of this rate to known molecular constants is consistent with recent theory of cold molecular collisions and outlines the (2)Sigma molecules conducive to magnetic trapping.     

Soft X-ray radiation-induced electron emission from the surface of polarized ferroelectrics

Additional electron emission that reflects specific properties of ferroelectrics was detected after the negatively charged surface of these preliminarily polarized materials was exposed to soft X-radiation (hv) ≤3 kV). The properties of this emission, which is referred to as anomalous electron emission (AEE) and is excited in single-crystal and ceramic samples, are studied with a standard X-ray photoelectron spectrometer. It is shown that the parameters of AEE spectra correlate with the characteristics of the materials. The conclusions of the phenomenological theory of the phenomenon are in satisfactory agreement with the experimental results. Translated fromZhurnal Strukturnoi Khimii, Vol. 39, No. 6, pp. 1031–1036, November–December, 1998