Recyclable Nanoparticles as Catalysts for Green Organic Chemistry

这项研究计划的主要目标是设计新的可回收催化剂，以便在对环境影响最小的情况下进行有效的合成。催化现在几乎普遍应用于化学和石化过程中。这些催化剂中的大多数都是多相的，因为它们很容易在流动过程中回收或利用。在这种背景下，纳米颗粒可以将高活性和选择性与回收潜力结合在一起，成为弥合均相催化和多相催化之间差距的极佳候选者。然而，它们的反应活性仍有待于在基础水平上进行探索，以了解其表面起作用的反应机理，使观察到的选择性合理化，破译均相与非均相催化途径，最终设计专用催化剂。该方案旨在解决这些问题。它被分成三个轴。在第一章中，我们将考察由还原的铁和铜或金组成的磁性纳米颗粒对惠氏缩合反应和烯烃氧化反应的催化活性。我们还将研究氧化铁空心球的化学反应活性，这是一类具有催化氧化烯烃潜力的纳米材料。在第二个轴上，我们将使用功能化离子液体来研究铁纳米粒子在离子液体中的稳定性。这类纳米粒子稳定剂的特点是具有锚定物种，这里是磷化氢或膦，可以减轻铁的氧化倾向。这些颗粒将被用于烯烃加氢反应，并可能为生物质转化为燃料提供廉价的催化剂。最后，我们将探索将纤维素纳米晶作为手性载体用于多相对映选择性催化的可能性。描述了两种方法，一种依赖于Pd纳米颗粒的使用，另一种依赖于磷酸有机催化剂。在所有情况下，对映体的诱导都是由cnc的表面提供的。这些杂化产物可以用简单的膜进行分离。HQP拥有从纳米颗粒合成和表征、无机和有机合成到催化的各种技能，在该计划中接受培训的HQP处于进入就业市场的理想地位。

The main goal of this research programme is to design new recoverable catalysts for efficient synthesis with minimal environmental impact. Catalysis is now almost universally used in chemical and petrochemical processes. A majority of these catalysts are heterogeneous in nature because they are easy to recover or utilize in flow processes. In this context, nanoparticles, which may combine high activity and selectivity with potential for recovery, appear as excellent candidates to bridge the gap between homogeneous and heterogeneous catalysis. However, their reactivity still remains to be explored at a fundamental level to understand the reaction mechanisms at play on their surface, to rationalize the selectivity observed, decipher homogeneous vs heterogeneous catalytic pathways and finally design dedicated catalysts. This programme is aimed at addressing these question. It is divided in 3 axes. In the first one, we will explore the catalytic activity of magnetic nanoparticles composed of reduced iron and copper or gold, for the Huisgen condensation and the oxidation of olefins respectively. We will also investigate the chemical reactivity of hollow spheres of iron oxide, a class of nano material with potential for the catalyzed oxidation of olefins. In a second axis, we will investigate the stabilization of iron nanoparticles in ionic liquids using functionalized ionic liquids. This class of nanoparticle stabilizers features an anchoring species, here a phosphine or a phosphinine, that can alleviate the tendency of iron to oxidize. These particles will be tested for the hydrogenation of olefin reaction and may afford cheap catalysts for the conversion of biomass to fuels. At last, we will explore the possibility of using cellulose nanocrystallites as chiral supports for heterogeneous enantioselective catalysis. Two approaches are described, one relying on the use of Pd nanoparticles, one on phosphoric acid based organocatalysts. In all cases the enantiomeric induction is provided by the surface of the CNC. These hybrids are separable using simple membranes. With skills ranging from nanoparticles synthesis and characterization, inorganic and organic synthesis to catalysis, HQP trained in this programme are ideally positioned to enter the job market.