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In this report, poly[acrylic acid] gels containing Al 2 O 3 were prepared by simultaneous free-radical polymerization and sol–gel chemistry using different amounts of 3-(trimethoxysilyl)propyl methacrylate (TMPM) as a compatibilizer. The hybrid materials were used as supports for a rhodium catalyst in the chemoselective hydrogenation of 3-substituted aromatic nitro-compounds. The supported rhodium catalyst was prepared by an ion-exchange process. In situ H 2 flux was used to produce active species of the catalysts. The resulting materials were characterized by infrared spectroscopy, thermogravimetric analysis, solid-state 29 Si and 13 C NMR, X-ray diffraction, transmission/scanning electron microscopy, and X-ray photoelectron spectroscopy. All materials exhibited simultaneous interpenetrating hybrid network structures (SIHNs). The morphologies and physicochemical properties depended on the amount of TMPM used. The catalysts were found to be effective for the reduction of nitrobenzene in ethanol at room temperature and a hydrogen pressure of 20 atm. The most active and selective catalyst was used in the hydrogenation of different 3-substituted aromatic nitro-compounds. The hydrogenation reactions displayed high conversion levels and promoted exclusive –NO 2 group reduction, resulting in the sole formation of the corresponding amino-compound, with the exception of 1,3-dinitrobenzene, in which over-hydrogenation was detected. The presence of electron-donating/electron-withdrawing substituents at the 3-position resulted in different rates of –NO 2 group hydrogenation. This effect was quantified in terms of the Hammett relationship, in which the catalyst displayed a linear correlation between the substituent constant ( σ i ) and the hydrogenation rate, with the exception of –OH, –NH 2 , and –OCH 3 groups. One explanation for this behavior is a proposed support-substrate hydrogen bond interaction during the catalytic reaction. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel Rh-containing non-phosphorous supported catalysts for tandem hydroformylation-hydrogenation were obtained. • Tertiary nitrogen atoms of the polymer anchored on material's surface promote aldehyde hydrogenation over Rh active centers. • Catalysts showed high activity (hydroformylation TOF 206 h−1) and chemoselectivity. • Catalyst K N performed stable hydroformylation yield at least in the first 5 cycles with a decrease in alcohol selectivity. Non-phosphorous rhodium-containing catalysts for direct conversion of olefins to alcohols via tandem hydroformylation/hydrogenation have been designed and synthesized. Interaction between Rh(acac)(CO) 2 and tertiary amino groups on the surface of mesoporous hybrid organic-inorganic supports yielded materials which were successfully used in the tandem process. Data obtained for a selected catalyst K N demonstrate that rhodium is in the Rh+1 state highly dispersed on the surface and is bonded with nitrogen atoms both before and after use. Evaluation of the catalytic performance shows high activity (hydroformylation TOF 312 h−1), chemoselectivity and stable hydroformylation yield at least in the first 5 cycles with a decrease in alcohol selectivity. The influence of temperature, reaction time, total pressure, and molar CO/H 2 ratio of syngas on oxygenate yields is described. Type of the hydroformylation active sites and possible pathways for the observed decrease in hydrogenation are discussed. [ABSTRACT FROM AUTHOR]