Polyurea-encapsulated palladium(ii) acetate: a robust and recyclable catalyst for use in conventional and supercritical mediaElectronic supplementary information (ESI) available: representative experimental procedures. See http://www.rsc.org/suppdata/cc/b2/b200677b/

Abstract

Palladium(II) acetate microencapsulated in polyurea (MC-[Pd]) is an economical and versatile heterogeneous catalyst for a range of phosphine-free cross-coupling reactions in both conventional solvents and supercritical carbon dioxide (scCO2); the catalyst can be recovered by a simple filtration and recycled up to four times.

Hydrogenation of nitro compounds with supported platinum catalyst in supercritical carbon dioxide

“…Fig. 4 gives the results of 2,4-dinitrotoluene hydrogenation at different CO 2 pressures, in which mono-hydrogenation products, 2-nitro-4-aminotoluene (8) and 4-nitro-2-aminotoluene (9) were mainly formed along with small quantities of double hydrogenation product, 2,4-diaminotoluene (10), and others.…”

“…The combination of scCO 2 and solid catalysts would be a green chemistry reaction system in which no organic solvent is used and separation of the CO 2 solvent after use is easy. Several authors studied chemical transformations with supported metal catalysts in scCO 2 [6][7][8][9][10][11][12]. For example, Hitzler and Poliakoff reported continuous hydrogenation of cyclohexene and acetophenone in scCO 2 with a polysiloxane supported palladium catalyst [6].…”

Heck arylation of alkenes with aryl bromides by using supported Pd catalysts: a comparative study

“…The catalysts used were as follows: Pd/C [17,[19][20][21] one of the most widely used heterogeneous Pd catalysts in Heck reactions; Pd/BaSO 4 [22][23][24], which has been shown to act as a catalyst reservoir in Stille and Suzuki-Miyaura couplings, but rarely used in Heck arylations, and Pd EnCat 30 [25][26][27][28][29][30], a commercial Pd(OAc) 2 catalyst, obtained by microencapsulation of palladiumacetate in polyurea matrix, formed by the condensation of multi-functional oligoarylisocyanates [31][32][33][34][35]. The properties of Pd EnCat were reported by the manufacturer, where only low leaching of Pd was detected [36].…”

Palladium tetrazole–supported complex as an efficient catalyst for the Heck reaction

“…Many organic and inorganic supports such as activated carbon, zeolites, metal oxides, clays, organic polymers, mesoporous silica and capsules have been used in the preparation of novel catalytic systems [9][10][11][12][13][14][15][16][17]. Among these, organic polymers offer different ways of metal attachment to the polymer matrix via covalent or non-covalent bonding, through hydrogen bonding, as well as through ionic, hydrophobic or fluorous interactions [18].…”