Heterogeneization of a new Ru(II) homogeneous asymmetric hydrogenation catalyst containing BINAP and the N-tridentate bpea ligand, through covalent attachment on amorphous AlPO4 support

Abstract

Following a new methodology to obtain hybrid organic-inorganic solids, the homogeneous complex [Ru II (bpea) {(S)())(BINAP)}Cl](BF 4 ), (bpea = N,N-bis(2-pyridylmethyl)ethylamine and BINAP = 2,2¢-bis(diphenylphosphino)-1,1¢-binaphthyl) has been covalently immobilized on an AlPO 4 amorphous solid. It was tested in the successive liquid phase enantioselective hydrogenation of several prochiral substrates such us dimethyl itaconate, methyl 2-acetamidoacrylate and methyl 2-acetamidocinnamate, in CH 2 Cl 2 as solvent, ([subs]/[cat] = 0.016/0.000352 = 45.4), hydrogen pressure 6.8 atm and 50-70°C reaction temperatures. Results obtained indicate that the catalytic activity with a high enantioselectivity (99%) was maintained throughout 10 successive reactions. Furthermore, the immobilized catalyst was easily recovered when repeatedly used and handled for several days, under the same experimental conditions as those in a conventional heterogeneous supported Ru catalyst.

Biofuel that Keeps Glycerol as Monoglyceride by 1,3-Selective Ethanolysis with Pig Pancreatic Lipase Covalently Immobilized on AlPO4 Support

“…The amorphous aluminium phosphate (AlPO 4 ) used as support for the covalent immobilization of PPL was obtained according to the sol-gel method used elsewhere to obtain other metal phosphates, metal supports and heterogeneous catalysts in different organic synthesis reactions [56][57][58][59][60], as well as in the covalent immobilization of several enzymes and organometallic complexes [48,[52][53][54][55]. Thus, this amorphous AlPO 4 (Al/P = 1) employed as PPL support was specially developed to obtain solids with high surface area and high density of Brönsted acid sites, what making them particularly suitable for the surface functionalization with some organic molecules, through the reaction of the surface acid sites with amino or hydroxyl groups of these activating molecules [48,[52][53][54][55].…”

“…Thus, this amorphous AlPO 4 (Al/P = 1) employed as PPL support was specially developed to obtain solids with high surface area and high density of Brönsted acid sites, what making them particularly suitable for the surface functionalization with some organic molecules, through the reaction of the surface acid sites with amino or hydroxyl groups of these activating molecules [48,[52][53][54][55]. In this way, amorphous AlPO 4 was prepared by precipitation from aqueous solutions of AlCl 3 ·6H 2 O and H 3 PO 4 (85 wt%) at pH = 6.1 at the "precipitation end point", with ammonium hydroxide solution, according to the chart flow outlined in Figure 4.…”

“…Comparatively, most studied lipases are intracellular materials obtained from bacteria or fungi, so that optimum operation conditions employed in such cases are close to neutral pH conditions. Covalent immobilization of PPL is carried out by using a methodology previously described in the heterogeneization of lipases [48][49][50][51], other enzymes like phosphatase [52] or glucose oxidase [53], as well as homogeneous organometallic complexes [54,55]. Taking into account the excellent results obtained in the immobilization of these enzymes, we have extended the possibilities of this methodology to be applied to the covalent attachment of PPL for use as an economically viable biocatalyst for the production of a novel biofuel integrating glycerol into its composition.…”

“…In this regard, we have previously reported the use of amorphous AlPO 4 as a metal support [57], as well as for heterogeneous catalysts in the field of selective organic synthesis [58][59][60]. This amorphous material, tailored by a controlled sol-gel method that allows us to obtain a high surface area as well as a high number of surface -OH groups, is a very adequate support component for the covalent attachment of enzymes, according to the results obtained in the immobilization of lipases, phosphatase and GOD enzymes [48][49][50][51][52][53] as well as homogeneous organometallic complex [54,55].…”

Membranas Poliméricas de PE-g-MA-Al/AlPO4 Impregnado com Fe, Al Utilização na Recuperação de Efluentes de Galvanoplastia

“…O gel formado foi lavado com álcool etílico comercial, filtrado à vácuo e seco em estufa a 80 °C por 24 horas [15,16] . Os aglomerados formados após à secagem foram desagregados e o pó resultante foi calcinado a 350 °C durante 3 horas, com uma taxa de aquecimento de 10 °C/min, para eliminação de reagentes residuais [17] . Esse material foi impregnado com ferro e/ou alumínio utilizando as soluções concentradas de FeCl 3 .6H 2 O e/ou AlCl 3 .…”