Mass spectrometric study of products and intermediate compounds in oscillating chemical reactions of oxidation of macrocyclic copper and nickel complexes by a bromate

Products and intermediate compounds formed in oscillating chemical reactions of oxidation of copper and nickel tetraazamacrocyclic complexes were studied by the method of desorption field mass spectrometry. It was shown that a cascadelike oxidation of the macrocyclic ligand takes place and its hydrolysis with rupture of the macrocyclic ring at the azomethine bonds. Products of bromination of oxygen- and nitrogen-containing compounds, participants in the reactions, were discovered.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 23, No. 2, pp. 221–225, March–April, 1987.     

The catalytic efficiency of Fe-containing nanocomposites based on highly dispersed silica in the reaction of CO2 hydrogenation

Research on Chemical Intermediates - Oxide Ni(80)Fe(20)/SiO2, Co(93)Fe(7)/SiO2, and Ni(19)Co(77)Fe(4)/SiO2 nanocomposites (NCs) were prepared using highly dispersed silica. It was modified by...     

Barothermal Diels-Alder functionalization of multi-walled carbon nanotubes

Abstract

Multi-walled carbon nanotubes (MWCNTs) have an ordered geometric structure, large specific surface area, prominent electrical conductivity, and unique mechanical properties. They are nontoxic and can be used in biomedicine. Physical and surface chemical characteristics of MWCNTs should be tuned to that required to improve certain properties and obtain a variety of functional materials. We modified the MWNTs by using the barothermal Diels-Alder reaction with dienophiles, p-benzoquinone, fumaronitrile, and maleimide, to address this issue. The prepared MWCNTs were studied by SEM-EDX, nitrogen adsorption porometry, ATR FTIR, and thermal analysis. Results showed that both separate and conjugated C?=?C bonds at the edge and outer/inner surface of walls could react with dienophiles. The grafted groups are separated by the temperature on weak (low-temperature) and strong (high-temperature) chemisorbed forms; they are detached at temperatures below and above 350?°C, correspondingly. Thermal analysis shows that up to 5% of the carbon atoms are involved in the [4?+?2] cycloaddition. The high-temperature forms of the grafted groups under extreme heating can be involved in the retro-Diels-Alder reaction that breaks six-membered rings, producing a dienophile.     

Catalytic and adsorption properties of iron-nickel catalysts in ammonia synthesis

Thermal desorption was used to study the state of chemisorbed nitrogen on the surface of iron-nickel ammonia-synthesis catalysts in the region of the solid solution of nickel and iron. It was shown that the ₁ form of nitrogen should be responsible for catalysis.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 24, No. 5, pp. 616–618, September–October, 1988.     

Dissociation and rearrangement of molecular ions of acetals in the field mass spectrometer

Theoretical and Experimental Chemistry -     

Effect of a metallic filler on the composition of the low-molecular products of the radiolysis of polyethylene

Field mass spectrometry has been used to investigate the composition of the volatile products of radiolysis of pure polyethylene and of polyethylene mixed with disperse carbonyl iron or with steel powder. With carbonyl iron as filler there was a marked increase in the intensity of the line in the mass spectrum due to the ions of methanol (32 amu), which may be attributed to the oxidation of the end groups of the polymer chains by oxygen chemisorbed on the surface of the metal under the influence of the ionizing radiation.L. V. Pisarzhevskii Institute of Physical Chemistry, Academy of Sciences of the Ukrainian SSR, Kiev.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 27, No. 2, pp. 223–228, March, 1991. Original article submitted September 14, 1989.