147-73-9Relevant articles and documents
Decorated single-enantiomer phosphoramide-based silica/magnetic nanocomposites for direct enantioseparation
Karimi Ahmadabad, Fatemeh,Pourayoubi, Mehrdad,Bakhshi, Hadi
, p. 27147 - 27156 (2019/09/12)
The nano-composites Fe3O4SiO2(-O3Si[(CH2)3NH])P(O)(NH-R(+)CH(CH3)(C6H5))2 (Fe3O4SiO2PTA(+)) and Fe3O4SiO2(-O3Si[(CH2)3NH])P(O)(NH-S(-)CH(CH3)(C6H5))2 (Fe3O4SiO2PTA(-)) were prepared and used for the chiral separation of five racemic mixtures (PTA = phosphoric triamide). The separation results show chiral recognition ability of these materials with respect to racemates belonging to different families of compounds (amine, acid, and amino-acid), which show their feasibility to be potential adsorbents in chiral separation. The nano-composites were characterized by FTIR, TEM, SEM, EDX, XRD, and VSM. The VSM curves of nano-composites indicate their superparamagnetic property, which is stable after their use in the separation process. Fe3O4, Fe3O4SiO2, Fe3O4SiO2PTA(+) and Fe3O4SiO2PTA(-) are regularly spherical with uniform shape and the average sizes of 17-20, 18-23, 36-47 and 43-52 nm, respectively.
Plaster retarding composition
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Example 1, (2008/06/13)
The present invention is related to a calcium tartrate plaster retarding composition, characterised in that it has a mean particle size lower than 30 μm,The present invention is also related to the plaster comprising said composition and to the preparation process of said composition.
Oxidation of methyl and n-octyl α-D-glucopyranoside over graphite-supported platinum catalysts: Effect of the alkyl substituent on activity and selectivity
Vleeming, Johannes H.,Kuster, Ben F.M.,Marin, Guy B.
, p. 175 - 183 (2007/10/03)
The oxidation of methyl and n-octyl α-D-glucopyranoside to methyl and n-octyl α-D-glucopyranosiduronate with molecular oxygen over a graphite-supported platinum catalyst was investigated. An increase of the length of the n-alkyl substituent from methyl to n-octyl resulted in a ten-fold decrease of the catalyst activity and an increase of the selectivity at pH 8.0 and 323 K. The selectivity decreased with increasing pH. The lower activity for a longer n-alkyl substituent is attributed to steric effects upon adsorption on the platinum surface and not to internal diffusion limitations. A tentative reaction scheme is presented, which describes the formation of side products through oxidation of secondary hydroxyl groups, ring cleavage and hydrolysis. Major side products are mono- and di-carboxylates with 2, 4, and 6 carbon atoms and mono-carboxylates, resulting from the oxidation of the alkyl substituent. C-C-Bond cleavage mainly occurs between C-2 and C-3 or C-4 and C-5, the former being less important for a longer alkyl substituent. The higher selectivity for a longer alkyl substituent is attributed to its protecting ability against hydrolysis and the exposition of neighboring hydroxyl groups to the platinum surface.
