Search

Your search keyword '"K. A. Gavrilov"' showing total 3 results
Start Over Author "K. A. Gavrilov" Language english
3 results on '"K. A. Gavrilov"'

1. ION MICROPROBE STUDIES OF REACTIONS IN SQUEEZE-CAST ALUMINUM-ALLOY MATRIX COMPOSITES

Author

David B. Williams, K. L. Gavrilov, A. G. Adriaens, Patrick S. Grant, H. G. Kang, K. K. Soni, Riccardo Levi-Setti, R. Mogilevsky, M. W. Tseng, and B. Cantor

Subjects
Microprobe, Histology, Materials science, Metal matrix composite, engineering.material, Chemical reaction, Pathology and Forensic Medicine, Secondary ion mass spectrometry, Matrix (chemical analysis), Coating, visual_art, engineering, Aluminium alloy, visual_art.visual_art_medium, Composite material, Layer (electronics)
Abstract

Summary An ion microprobe with high lateral resolution has been used to study the chemical reactions at the fibre/matrix interface of metal–matrix composites. During the squeeze-casting process, the Al–Si–Mg matrix reacts with the preform made of Saffil fibres (96% Al2O3, 4% SiO2). The reaction occurs mainly between the silica binder and Mg from the matrix according to SiO2 + 2Mg = 2MgO + Si. A continuous layer of MgO was formed around the fibres, even on surfaces that were not covered by the silica binder. Possible reasons are discussed for the formation of MgO in areas where binder coating was missing. In such areas, Mg reduces SiO2 that is contained in the fibre. However, the fibres (A12O3) are not attacked by Mg. In the isolated case of fibres that were completely uncoated, no reaction products were observed at the interface. The presence of silica binder seems to be an essential requirement for this reaction to occur. When squeeze-casting is performed with sufficiently high melt temperature, Al from the matrix also reduces silica.

Published
2016
Full Text
View/download PDF

2. Complexation and Pd-Catalyzed Asymmetric Allylation with Participation of Chiral Ferrocenyliminophosphites.

Author

K. N. Gavrilov, V. N. Tsarev, S. E. Lubimov, S. V. Zheglov, and V. A. Davankov

Abstract

Chiral ferrocene-containing iminoarylphosphite ligands based on 4,4'-dimethoxy-6,6'-di-tert-butyl-biphenyldiol-2,2' and their chelate complexes with Rh(I) and Pd(II) were synthesized for the first time. They were shown to be perspective reagents in the reactions of asymmetric allyl substitution. The Pd-catalyzed alkylation of 1,3-diphenylallylacetate with dimethyl malonate results in a 87% enantiomer excess (ee), while in sulfonylation of 1,3-diphenylallylacetate with sodium para-toluenesulfinite, this figure amounts to 67%. The results obtained were compared with coordination and catalytic efficiency of a less sterically hindered ferro-cenyliminophosphite based on pyrocatechol. The compositions and structures of new compounds were determined by the 1H, 13C, 31P NMR, IR, mass spectrometry (EI, FAB, and electrospray techniques), and elemental analysis. [ABSTRACT FROM AUTHOR]

Published
2004

3. A first P,N-bidentate phosphite with a chiral ketimine fragment. Catalytic properties of its RhI and PdII complexes in comparison with those of phosphine analogs.

Author

V. N. Tsarev, S. E. Lyubimov, S. V. Zheglov, A. A. Shiryaev, V. A. Davankov, and K. N. Gavrilov

Subjects
MENTHOL, RHODIUM, ALKALI metals, ALKYLATION
Abstract

Abstract A chiral P,N-bidentate aryl phosphite ligand containing peripheral (R)-(+)-camphor-derived ketimine and its rhodium(I) and palladium(II) chelate complexes were synthesized for the first time. These compounds were found to be suitable for asymmetric allylic substitution. The Pd-catalyzed sulfonylation of 1,3-diphenylallyl acetate with sodium p-toluenesulfinate gave the product in 73% ee; in the alkylation of the same substrate with dimethyl malonate, the ee was 94%. These ee values are higher than the enantioselectivity achieved with the known phosphine analogs. [ABSTRACT FROM AUTHOR]

Published
2004

Catalog

Books, media, physical & digital resources
See catalog results