Hydrogenation of acetylenics by Pd-exchanged mesoporous materials

Palladium Nanoparticles Suspended in an Ionic Liquid as Reusable Catalyst for Alkyne Semihydrogenation

“…Most studies in recent years about hydrogenation of alkynes have focused on the use of supported palladium catalysts. Pd on SiO2, [1][2][3] Pd on Al2O3, [4][5][6][7] Pd on Carbon, [8][9][10] Pd on pumice, 11,12 Pd on CeO 2 13 and palladium supported on mesoporous montmorrilonite clay 14,15 and microporous zeolite materials 16 were applied. Much effort has been made to empirical modifications of such palladium based catalysts to improve the desired selectivity.…”

Pd/SiO2 catalysts: synthesis of Pd nanoparticles with the controlled size in mesoporous silicas

“…Work has been directed toward the synthesis of nanoparticles (nanowires) of the metals, such as palladium [20][21][22][23][24][25][26][27][28][29][30][31][32][33], platinum [8,20,[34][35][36][37][38][39][40], ruthenium [41][42][43][44][45][46][47], gold [48][49][50][51], silver [36,52], within the channels of mesoporous silicates, mainly, MCM-41. The metals were introduced into the support either directly during the mesoporous silicate synthesis, or by post-synthesis treatment.…”

“…Direct incorporation was performed adding the metal precursor into the synthesis silica gel before ageing [34,37,45] or by a stabilisation of the metal precursor inside the template micelles during the self-assembly of the surfactant and silicate [30,32,47]. The post-synthesis metal deposition was carried out using a calcined mesoporous support via incipient wetness impregnation [35,39], ion-exchange [25][26][27]53], equilibrium adsorption, metal complex immobilisation [8,22], and vapour-phase grafting [23,31]. The extensively employed methods of support impregnation and addition of a metal precursor into the synthesis gel lead to the uncontrolled growth of metal particles inside the pores and on the external support surface, resulting in a broad particle size distribution.…”

Recent Development of Palladium-Supported Catalysts for Chemoselective Hydrogenation

“…Another remarkable feature of Pd/CR11 is its reusability: it can be reused for at least five runs without any palladium leaching. 62) While clay, a raw material of ceramics, has been used for a support of the heterogeneous palladium catalyst for the hydrogenation of various functionalities, [31][32][33][34][35][36][37][38][39][40][41][42][43][44][73][74][75][76][77][78][79][80][81][82][83] the use of a ceramic as a catalyst support is very limited. 84) Although the components of the ceramic that we used for catalyst support are very similar to those of molecular sieves 3A and 5A, the ceramic contains a variety of elements, such as magnesium, titanium, iron, sulfur, and zirconium, in addition to the common elements oxygen, silicon, aluminum, potassium, and sodium.…”