14250-96-5Relevant articles and documents
Isomerisation and controlled condensation in an aqueous medium of allyl alcohol catalysed by new water-soluble rhodium complexes with 1,3,5-triaza-7-phosphaadamantane (PTA)
Smolenski, Piotr,Kirillova, Marina V.,Guedes Da Silva, M. Fatima C.,Pombeiro, Armando J. L.
, p. 10867 - 10874 (2013)
New aqua-soluble rhodium(i) [Rh(CO)(PTA)4]Cl (1) (PTA = 1,3,5-triaza-7-phosphaadamantane) and rhodium(iii) [RhCl2(PTA) 4]Cl (2) complexes have been synthesized via the reaction of [{Rh(CO)2(μ-Cl)}2] or RhCl3·3H 2O, respectively, with stoichiometric amounts of PTA in ethanol. Compound 1 is also obtained upon reduction of 2 in an H2/CO atmosphere. They have been characterized by IR, 1H and 31P{H} NMR spectroscopies, elemental and single crystal X-ray diffraction analyses. While compound 1 shows distorted square-pyramid geometry (τ5 = 0.09) with a P3C-type basal plane, compound 2 is octahedral with the chloro ligands in the cis position. The hydride rhodium(i) complex [RhH(PTA)4] (3) is formed upon the addition of NaBH 4 to an aqueous solution of 1 or 2. Compounds 1-3 (in the case of 2 upon reduction by H2) act as homogeneous catalysts, or catalyst precursors, in the isomerisation and condensation of allyl alcohol at room temperature and in an aqueous medium. The product selectivity is easily controlled by changing the concentration of the base in the reaction mixture, thus resulting in the exclusive formation of either 3-hydroxy-2-methylpentanal (HP) or 2-methyl-2-pentenal (MP) in quantitative yields. The Royal Society of Chemistry 2013.
Suyama,Adachi
, p. 1417,1420 (1979)
Lablache-Combier,Pollet
, p. 3141,3150 (1972)
Heterogeneous catalytic condensation of propanal
Afaunov, A. A.,Bruk, L. G.,Flid, V. R.,Martsinkevich, E. M.
, p. 2031 - 2033 (2021/11/04)
The aldol homocondensation of propanal was studied in the presence of a heterogeneous titanium oxide catalyst modified with amino acid (AA) l-norleucine. The effects of the temperature and l-norleucine content on the conversion of propanal and selectivity of the process were studied. The reaction products were identified, and possible mechanisms are considered. A new catalyst (5% AA on titanium dioxide) was developed for the synthesis of 2-methyl-2-pentenal with the selectivity >90%.
SELF-CONDENSATION OF ALDEHYDES
-
Paragraph 0021; 0027, (2020/06/05)
An efficient process useful for the self-condensation of aliphatic aldehydes is provided, catalyzed by dialkylammonium carboxylate salts. In particular, the invention provides a facile method for the preparation of 2-ethyl hexenal via the self-condensation of butyraldehyde using various dialkylammonium carboxylates, e.g., diisopropylammonium acetate or dimethylammonium acetate, as catalyst. Additionally, residual nitrogen arising from the catalyst can be reduced to -100 ppm levels in the product via a simple washing procedure. The invention provides a process for preparing alkenals under conditions which limit the formation of undesired impurities and high-boiling oligomeric substances.