Effect of Low-Molecular-Weight Cationic Praestols on the Efficiency of Water Pretreatment at Heat and Electric Power Plants

The efficiency of water pretreatment at heat and electric power plants using low-molecular-weight cationic Praestols (coagulants) in combination with lime, iron sulfate, and flocculant (high-molecular-weight anionic Praestol) was studied.     

Microwave spectra ofs-cis-Glyoxal (CHO−CHO) molecules in excited vibrational states

The microwave spectra of s-cis-glyoxal molecules in the excited states of torsional (v_t=1,2) and bending (v_bend=1) vibrations have been studied. For the v_t=1 state, the rotational constants have been refined and the quartic constants of centrifugal distorition have been determined. For the excited v_t=2 and v_bend=1 states, the rotational constants have found. For the ground vibrational state, the rotational constants and the quartic constants of centrifugal distortion have been refined. The vibrational frequencies have been determined from the relative intensities of rotational transitions. Ufa Scientific Center of Russian Academy of Sciences, Physics Department. Translated fromZhurnal Strukturnoi Khimii, Vol. 36, No. 3, pp.418–423, May–June, 1995. Translated by I. Izvekova     

Determination of constants of the reaction of epoxy model compounds with organic amines in actual conditions

Kinetic studies of the interaction of monoepoxides with primary and secondary monoamines are carried out. It is shown that the reactivity of the epoxide ring of an active modifier depends on the structure during interaction both in bulk and in solvent environment. It was found that the ratio of the constants of the reaction of primary amino groups with an epoxy ring to the constants of the secondary amine is about 2.     

NHC Polymeric Particles Obtained by Self-Assembly and Click Approach of Calix[4]Arene Amphiphiles as Support for Catalytically Active Pd Nanoclusters

A new polymeric NHC carrier was synthesized by sequential supramolecular self-assembly and copper-catalyzed azide-alkyne cycloaddition (CuAAC) of amphiphilic imidazolium calix[4]arenes with octyl lipophilic fragments. Obtained polytriazole-imidazolium particles were found as monodisperse submicron particles, with the average diameter of 236 ± 34 nm and average molecular weight of 1380 ± 96 kDa. Successful CuAAC polymerization has been proved using IR spectroscopy and high-resolution ESI mass spectrometry. Polymeric particles, as well as aggregates made from precursor macrocycles, were decorated by Pd clusters (2 nm) for further catalytic investigations. Pd nanoclusters, supported on the polymeric surface, were found highly catalytically active in the model reduction of p-nitrophenol, giving reaction rates an order of magnitude higher compared to literature examples. The reaction was recycled using the same catalyst five times without any loss of activity.     

Stereoselective synthesis of tetrazole CB92834, a potent retinoid compound

An improved, convergent synthesis of CB92834 is relying on a Suzuki cross-coupling reaction and easily allows multigram-scale preparation of the compound. The approach features three highly stereoselective steps.     

Study of the membrane-extraction properties of O-hexyl-(N,N-di-2-ethylhexyl)methylphosphonic acid

ABSTRACT

It was found that the O-hexyl-(N, N-di-2-ethylhexyl)methylphosphonic acid is a good membrane carrier for lithium ion. Thus, the O-hexyl-(N, N-di-2-ethylhexyl) methylphosphonic acid exhibits a sufficiently high ability to transfer lithium and sodium ions through the liquid membrane, and also exhibits high selectivity for lithium ions.     

New bifunctional amphiphilic oxyethylimidazolium derivatives of calix[4]arene containing alkynyl/azide fragments: regularities of aggregation and polymerization under azide/alkyne cycloaddition conditions

Russian Chemical Bulletin - New bifunctional amphiphilic oxyethylimidazolium derivatives of calix[4]arene with terminal alkynyl or azide fragments in the polar moiety of the molecule were...