Recyclable Nanoparticles as Catalysts for Green Organic Chemistry

本研究计划的主要目标是设计新的可回收催化剂，以实现高效合成，同时对环境的影响最小。催化现在几乎普遍应用于化学和石油化工过程。这些催化剂大多是多相的，因为它们很容易在流动过程中回收或利用。在这种情况下，纳米颗粒可能结合了高活性、选择性和潜在的回收，成为弥合均相和非均相催化之间差距的优秀候选人。然而，它们的反应活性仍然需要在基础水平上进行探索，以了解其表面的反应机制，使所观察到的选择性合理，破译均相和多相催化途径，并最终设计专用催化剂。本方案旨在解决这些问题。它被分成3个轴。在第一个实验中，我们将探索由还原铁和铜或金组成的磁性纳米颗粒分别对Huisgen缩合和烯烃氧化的催化活性。我们还将研究空心氧化铁球的化学反应性，这是一类具有催化烯烃氧化潜力的纳米材料。在第二个轴，我们将研究铁纳米颗粒在离子液体中使用功能化离子液体的稳定性。这类纳米颗粒稳定剂的特点是锚定物质，这里是磷化氢或磷化氢，可以减轻铁的氧化倾向。这些颗粒将用于烯烃加氢反应的测试，并可能为生物质转化为燃料提供廉价的催化剂。最后，我们将探讨利用纤维素纳米晶作为手性载体进行多相对映选择性催化的可能性。描述了两种方法，一种依赖于使用钯纳米粒子，一种依赖于磷酸基有机催化剂。在所有情况下，对映体感应是由CNC的表面提供的。这些杂交体可以用简单的膜分离。从纳米颗粒合成和表征，无机和有机合成到催化，HQP在这个项目中训练有素，是进入就业市场的理想定位。

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.