The mechanism of liquid-phase catalytic hydrogenation of the olefinic double bond on supported nickel catalysts

Abstract

The liquid-phase catalytic hydrogenation of several styrene derivatives, PhCH=CHR (R = H, CH,OH, CHO, COMe, C02H, and CO,Me), has been carried out at 293-333 K with 0.41 MPa of initial hydrogen pressure on nickel catalysts at 20 wt% supported on A1,03, Si O,, and on t w o different types of AIPO,. The metal-support interaction effects as well as the substituent effects can be evaluated through several isokinetic parameters obtained due t o the existence of a linear correlation between the activation parameters AHt and ASt (and between I n A and E,) known as the

Room Temperature, Reductive Alkylation of Activated Methylene Compounds: Carbon–Carbon Bond Formation Driven by the Rhodium-Catalyzed Water–Gas Shift Reaction

“…The resulting weakening of the double bond would account for a more facile hydride delivery in the formation of vi and explain the observed rates, if formation of vi were turnover-limiting. A similar manifestation of the push–pull effect has been documented in the Ni-catalyzed hydrogenation of styrene derivatives, for which the application of the Yukawa–Tsuno correlation furnished negative ρ values …”

“…A similar manifestation of the push−pull effect has been documented in the Nicatalyzed hydrogenation of styrene derivatives, for which the application of the Yukawa−Tsuno correlation furnished negative ρ values. 52 5.3. Comparison with Existing Methods.…”

Microwave-assisted efficient synthesis of azlactone derivatives using TsCl/DMF under solvent-free conditions

“…A literature search revealed that different reagents have been used for the synthesis of azlactones involving perchloric acid [9], polyphosphoric acid [10], carbodiimides [11], POCl 3 [12] and SO 3 in dimethylformamide [13]. Other reported routes for the synthesis of azlactones by condensation reaction of aldehydes with hippuric acid in acetic anhydride as dehydrating agent are in the presence of various catalysts such as Al 2 O 3 [14], Bi(OAc) 3 [15], Bi(OTf) 3 [16], silicasupported heteropolyacids [17], Yb(OTf) 3 [18], Ca(OAc) 2 [19], supported KF [20] and anhydrous zinc chloride [21]. Most of the methods are suitable; however, some of these procedures need high temperature (reflux temperature) and are difficult to handle.…”

EXAFS investigations of Ni/γ-Al2O3 and Ni/AlPO4 catalysts and their precursors

“…We have also prepared different metal loadings of nickel on A1PO 4 and compared these catalysts with the corresponding Ni/~-A1 z 0 3 catalysts, prepared under similar conditions. A1PO 4 which is isostructural with SiO 2 has been used as a support in a number of catalytic reactions (Alba et al 1986;Campelo et al 1986Campelo et al , 1988Bautista et al 1989;Rebenstore et al 1991).…”