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1.
A simple, efficient and highly chemoselective method for tetrahydropyranylation of alcohols and phenols has been developed by their reaction with 3,4-dihydro-2H-pyran at room temperature in the presence of a catalytic amount of polystyrene supported AlCl3. The method is also highly selective for monoprotection of symmetrical diols. 相似文献
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Dichang Zhang 《Journal of Thermal Analysis and Calorimetry》1995,45(1-2):141-150
A cracking catalyst designatedSRNY was manufactured from a commercialSRNY molecular sieve (M.S.). The support consisted of kaolin, clay and SiO2. The coking behaviour of theSRNY M.S., the support and the catalyst were examined with light diesel oil (LDO) as feedstock in a microreactor. The physico-chemical properties of both fresh and aged samples, subjected to or not subjected to the cracking reaction ofLDO, were sequentially characterized by means of pore structure determination and thermal analysis. The pore structure included the specific surface area and the pore volume or porosity. Thermal analysis methods used included TG and DSC. The results indicated that all coked samples exhibited obvious changes in surface pore structure and acidity in comparison with non-coked samples. Their specific surface area and acid amount decreased with increase in the coke content of the samples. The apparent activation energy data obtained from decoking samples in an air flow, using the temperature-programmed oxidation (TPO) method, showed that the kinetic parameters of theSRNY M.S. differed from those of theSRNY catalyst and its support. 相似文献
5.
Those who have worked in the Royal Institution of Great Britain have, since its foundation in 1799, made significant contributions
to scientific knowledge, to its practical application, and to its communication to a wide variety of audiences. Such work
cannot be carried out in an architectural vacuum, and in this paper we examine how the buildings of the Royal Institution,
20 and 21 Albemarle Street in central London, have shaped the work undertaken within its walls and how, on a number of occasions,
the buildings have been reconfigured to take account of the evolving needs of scientific research and communication.
This paper is based on the Conservation Plan of the Royal Institution that we wrote during 2003. The Conservation Plan did
not examine the land owned by the Royal Institution to the north (i.e., 22 and 23 Albemarle Street; for this area see Richard Garnier, “Grafton Street, Mayfair,” Georgian Group Journal 13 (2003), 210–272), but it did discuss 18 and 19 Albemarle Street. In this paper we concentrate on the core Royal Institution
buildings at 20 and 21 Albemarle Street. Other studies of the relationship of architecture,space, and science include Crosbie
Smith and Jon Agar, ed., Making Space for Science: Territorial Themes in the Shaping of Knowledge (Basingstoke: Macmillan, 1997); Peter Galison and Emily Thompson, ed., The Architecture of Science (Cambridge, Mass.: MIT Press, 1999); and Sophie Forgan,“The architecture of science and the idea of a university,” Studies in History and Philosophy of Science 20 (1989), 405–434.
Frank A.J.L. James is Professor of the History of Science at the Royal Institution; he has written widely on the history of
nineteenth-century science in its social and cultural contexts and is editor of the Correspondence of Michael Faraday. He is President of the British Society for the History of Science. Anthony Peers is an Associate of Rodney Melville and
Partners where he works in the field of building conservation as an architectural historian. He is a Council member of the
Ancient Monument Society. 相似文献
6.
We review the unusual structural, transport and magnetic properties of highly conducting polyaniline, doped with boron trifluoride.
Our studies establish the unique conducting state of this system, which is in distinct contrast with the conventional proton-doped
polyaniline samples. 相似文献
7.
Katsumi Kubota 《Tetrahedron》2006,62(49):11397-11401
The first highly enantioselective silicon Lewis acid catalyst for an asymmetric organic transformation has been developed. The catalyst derives its activity from the strain induced in the silicon center by virtue of being constrained in a five-membered ring. A simple tridentate ligand has been developed and the derived chlorosilane complex catalyzes the Diels-Alder cycloaddition of methacrolein and cyclopentadiene with 94% ee. 相似文献
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Efficient synthesis of ferrocenylenones using a Friedel-Crafts acylation reaction is described. Acryloyl, methacryloyl, crotonoyl, cinnamoyl, and β-methylcrotonoyl chlorides react with ferrocene in the presence of a Lewis acid (EtAlCl2 or EtAlCl2-Me3Al) to give the corresponding ferrocenylenones (acryloyl, methacryloyl, crotonoyl, cinnamoyl, and methylcrotonoylferrocenes) in good isolated yields. Besides ferrocenylenones, chloroactylferrocene is also synthesised by this method. 相似文献
10.
The enthalpies and free energies of proton affinity (PA) were calculated by the PM3 method for 27 thiophenoxide anions. For thiophenols, linear correlation has been found between the PAs and the values of pK
a
measured by different authors in aqueous acetone, aqueous ethanol, and methanol media. The dependences found permit one to predict a priori the protolytic properties of thiophenols. The differential effects of aqueous ethanol media with different ethanol contents on thiophenol acidity were evaluated based on quantum-chemical data.Original Russian Text Copyright © 2004 by A. N. Pankratov and A. V. Shalabai__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 5, pp. 800–806, September–October, 2004. 相似文献