1758-73-2Relevant articles and documents
HETEROGENEOUS SYNTHESIS OF METHYLENE DIANILINE
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Page/Page column 33-35, (2021/06/22)
The present invention relates to a catalytic material for the preparation of one or more of 4,4'- methylenedianiline, 2,2'-methylenedianiline, 2,4'-methylenedianiline, and oligomers of two or more thereof, the catalytic material comprising an oxidic support, wherein the oxidic support comprises an element EOS1 selected from the group consisting of Ti, Zr, Al, Si, and mixtures of two or more thereof, and further comprising a supported material supported on the oxidic support, wherein the supported material comprises an element ESM1 selected from the group consisting of Ti, Zr, V, Nb, Ta, Mo, W, Ge, Sn, Sc, Y, La, Ce, Nd, Pr, Hf, Cr, Fe, Co, Ni, Cu, Zn, Pb, and mixtures of two or more thereof. Further, the present invention relates in particular to a process for the preparation of a catalytic material and to a process for the preparation of one or more of 4,4'-methylenedianiline, 2,2'-methylenedianiline, 2,4'-methylenedianiline and oligomers of two or more thereof.
Lewis acid solid catalysts for the synthesis of methylenedianiline from aniline and formaldehyde
Cheung, Ka Yan,De Baerdemaeker, Trees,De Vos, Dirk,Gordillo, Alvaro,Marquez, Carlos,Parvulescu, Andrei-Nicolae,Tomkins, Patrick
, p. 114 - 123 (2021/06/16)
A catalyst containing Hf4+ and Zn2+ supported on silica has been found to be highly effective for the synthesis of methylenedianiline (MDA), an indispensable precursor in the polyurethane industry. Its performance was further improved when the silica support was replaced by silica-alumina, which resulted in a catalyst that was both active and selective, as indicated by the high MDA yield and high 4,4′–MDA/(2,2′–MDA + 2,4′–MDA) isomer ratio obtained. Furthermore, the catalyst also gave an appreciable oligomeric MDA (OMDA) yield and was noticeably more stable than the zeolites that were used in comparative tests: it could be used in at least five consecutive runs without any significant loss in activity. The combination of Br?nsted and Lewis acidity strongly increases the overall activity and yields a catalyst that represents a remarkably stable and reusable alternative to the commonly studied systems for this reaction.
Selective oxidation of thiourea with H2O2 catalyzed by [RuIII(edta)(H2O)]-: Kinetic and mechanistic studies
Chatterjee, Debabrata,Rothbart, Sabine,Van Eldik, Rudi
, p. 4725 - 4729 (2013/05/09)
Reported here is the first example of a ruthenium complex, [Ru III(edta)(H2O)]- (edta4- = ethylenediaminetetraacetate), that catalyzes the oxidation of thiourea (TU) in the presence of H2O2. The kinetics and mechanism of this reaction were investigated in detail by using rapid-scan spectrophotometry as a function of both the hydrogen peroxide and thiourea concentrations at pH 4.9 and 25 °C. Spectral analyses and kinetic data clearly support a catalytic process in which hydrogen peroxide reacts directly with thiourea coordinated to the RuIII(edta) complex. HPLC product analyses revealed the formation of formamidine disulfide (TU2) as a major product at the end of the catalytic process, however, formation of other products like thiourea dioxide (TUO2), thiourea dioxide (TUO3) and sulfate was also observed after longer reaction times. Catalytic intermediates such as [Ru III(edta)(OOH)]2- and [RuV(edta)(O)] - were evidently found to be non-reactive in catalyzing the oxidation of thiourea by H2O2 under the specified conditions. The Royal Society of Chemistry 2013.