82941-26-2Relevant articles and documents
Ceria supported gold-platinum catalysts for the selective oxidation of alkyl ethoxylates
Heidkamp, Katharina,Aytemir, Memet,Vorlop, Klaus-Dieter,Pruesse, Ulf
, p. 2984 - 2992 (2013/11/06)
This work covers the development of a ceria based AuPt catalyst for the selective aerobic oxidation of alkyl ethoxylates to their corresponding carboxylic acids. By optimizing metal loading and the Au to Pt ratio the activity of the catalyst could be increased significantly, while maintaining total selectivity. Although the choice of ceria as a support helped to suppress intermediate metal leaching, the catalyst still showed poor long-term stability in repeated batches. The cause for deactivation could finally be identified by TPR studies as over-oxidation. These suspicions were confirmed by a long-term stability study in continuous-mode. It proved to be possible to deactivate the catalyst on purpose by employing unfavourable oxidising reaction conditions, i.e. low substrate concentrations and excess oxygen. By avoiding such unfavourable conditions either in continuous-flow mode or in repeated batches, the long-term stability of the catalyst increased tremendously. A substrate screening of various ethoxylates showed that the catalyst was very well-suited to selectively oxidize a wide range of alkyl ethoxylates.
Trifluorothymidine derivatives, process for producing the same and anti-cancer agent containing the same
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, (2008/06/13)
Novel trifluorothymidine derivatives having anti-cancer activities are disclosed. The trifluorothymidine derivatives of the present invention are represented by the formula [I]: (wherein R1 represents hydrogen atom or C1 - C4 alkyl group; R2 represents hydrogen atom, C1 - C30 saturated or unsaturated alkyl-substituted carbonyl group, alkyl-substituted benzoyl group, C1 - C4 alkyloxycarbonyl group; dimethylaminoethyloxycarbonyl group, C1 - C4 alkyloxymethyl group, butoxyethoxyacetyl group, benzyl group, C1 - C20 alkyl-substituted silyl group, silyl group substituted with C1 - C10 alkyl group and/or phenyl group, C1 - C30 cyclic or chain alkyl-substituted carbamoyl group, diethylaminopropylcarbamoyl group, N-alkylpiperazinylacetyl group, N-alkylprolyl group, valyl group, trityl group, alkyl-substituted phosphoryl group or propargyl group; R3 represents hydrogen atom, C1 - C4alkyl group, benzyl group, benzoyl group, C1 - C4 alkyloxy-substituted benzoyl group, furoyl group, C1 - C4 alkyloxymethyl group or C1 - C4 alkyl-substituted carbonyl group).