Platinum Nanoparticles Supported on Ionic Liquid‐Modified Magnetic Nanoparticles: Selective Hydrogenation Catalysts

Abstract

A method for supporting platinum nanoparticles on magnetite nanoparticles is described. The method requires modification of the surface of the magnetic nanoparticles with ionic liquid groups. Before modification, the magnetic nanoparticles are not stable and easily aggregate and, after modification, the magnetite nanoparticles become highly stable and soluble in polar or non‐polar organic solvents depending on the alkyl group of the linked ionic liquids. The supporting of platinum nanoparticles on the modified magnetic nanoparticles was achieved by adsorbing platinum salts (K2PtCl4) on the surface of the magnetite nanoparticles via ion exchange with the linked ionic liquid groups and then reducing them by hydrazine. The supported platinum nanoparticles were applied in the catalytic hydrogenation of alkynes in which cis‐alkenes were selectively produced, and in the hydrogenation of α,β‐unsaturated aldehydes where the allyl alcohols were obtained as the exclusive products. The new catalyst can be easily separated from the reaction mixtures by applying an external magnetic field and recycled.

Magnetically Separable Base Catalysts: Heterogeneous Catalysis vs. Quasi-Homogeneous Catalysis

“…We have described the highly selective hydroformylation reaction using rhodium catalysts supported on dendronized magnetic nanoparticles [33]. We have also developed a catalytic system for the chemoselective hydrogenation of α, β-unsaturated aldehydes and alkynes, based on platinum nanoparticles supported on nano-magnetite, Fe 3 O 4 , modified with ionic liquid groups [34]. Furthermore, in our recent work we showed a method based on magnetic nanoparticles and sol-gel process that facilitates the separation of two solid catalysts after catalyzing one-pot reactions in a single vessel and enables their reuse in other catalytic reactions [35].…”

“…Magnetite Nanoparticles [34] Eleven point six grams of FeCl 3 ·6H 2 O and 4.3 g of FeCl 2 ·4H 2 O were mixed in 400 mL of degassed water. The mixture was heated at 85 °C, and then 15 mL of concentrated ammonia (28%) were added quickly.…”

Research Advances on the Applications of Immobilized Ionic Liquids Functional Materials

“…如磁性纳米粒子负载离子液体用于 CO 2 环加成反 应 [64] , 碱性离子液体官能化羟基磷灰石包埋 γ-Fe 2 O 3 纳 米粒子用于温和条件下 Knoevenagel 缩合反应 [65,66] , 离 子液体改性 Fe 3 O 4 负载 Pd-NHC-IL 用于 Suzuki 偶联反 应 [67] , 离子液体改性磁性纳米粒子负载 Pt 用于炔烃加 氢以及 α,β-不饱和醛加氢 [68] , 离子液体改性磁性纳米粒 子负载脂肪酶用于油酸酯化反应 [69] 等. 采用磁性纳米 粒子作为载体所制成的催化体系可以充分利用载体外 表面, 将离子液体暴露在反应介质中, 彻底消除了存在 于常规固体催化剂孔道内的扩散阻力, 而且易于磁分 离.…”

Hydrogenation in Ionic Liquids

“…The difference between reaction times was attributed to the typical biphasic conditions of the reactions performed in the ionic liquid, which can be a mass-transfer controlled process. [105] Abu-Reziq et al [112] used platinum nanoparticles supported on magnetite (Fe 3 O 4 ) modified with functionalised ionic liquids ( Figure 48). The ILs were readily synthesised by substitution reaction of the desired alkylimidazole with the alkyl chloride to furnish the alkylimidazolium chloride ILs.…”