Hierarchically porous (HP) zeotype materials (possessing both micropores and mesopores) offer improved diffusional access to intra-framework active sites, analogous to mesoporous materials, yet retain the high selectivity of the microporous (MP) bulk. We have recently designed crystalline hierarchically porous silicoaluminophosphates (SAPOs) with enhanced mass-transport characteristics, which can lead to significant improvement in catalytic activity and catalyst lifetime. In this study, we have prepared PdAu bimetallic nanostructures supported on HP-SAPO frameworks by an incipient impregnation of metal precursors followed by H2 reduction at 300 °C, for the aerobic oxidation of benzyl alcohol to benzaldehyde. PdAu NPs supported on HP framework displayed significantly enhanced catalytic activities, when compared with their MP analogues, clearly highlighting the benefits of introducing hierarchical porosity in the SAPO support matrix.

Please cite this article as: O'Brien, M., Cooper, D.A., Mhembere, P., The continuous-flow synthesis of carbazate hydrazones using a simplified computer-vision controlled liquid-liquid extraction system, Tetrahedron Letters (2016), doi: http://dx.doi.org/10.1016/j.tetlet. 2016.10.018 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Tetrahedron LettersThe continuous-flow synthesis of carbazate hydrazones using a simplified computervision controlled liquid-liquid extraction system. --- Corresponding author. e-mail: m.obrien@keele.ac.ukIn recent years, the emergence of continuous flow methodology has created new opportunities for chemical synthesis. 1 Compared with traditional batch processes, flow methods can often offer significant safety benefits, particularly for transformations involving hazardous conditions or reagents.2 Additionally, the small dimensional scales involved lead to the efficient and scaleinvariant interfacial transfer of energy and matter.3 A particularly attractive aspect of flow chemistry is the ability to incorporate inline purification stages. Solid-supported scavengers 4 and phaseswitching protocols have been extremely successful in this regard. 5 However, solid-supported chemicals can often be much more expensive than their solution phase counterparts. 6 In addition, they often give rise to significant and scale-dependent dispersion effects 7 and become depleted over time, thus requiring replacement or regeneration. This can be a time consuming operation which usually necessitates halting of the flow process. As liquids can be continuously pumped through the system, inline liquid-liquid phase separation does not suffer from this problem and, whilst dispersion cannot be eliminated, it can be controlled and rendered scale invariant.One general method of inline liquid-liquid separation used in continuous flow makes use of the selective wetting of certain materials, particularly expanded porous PTFE membranes, to separate aqueous and organic solutions. 8 We have been interested, however, in gravity-based separations of immiscible liquids based on their densities.9 This is essentially a continuous flow adaptation of the classical separating funnel. The basic concept is shown in Figure 1. A biphasic stream of immiscible liquids with differing densities will, when passed into a suitable vessel, separate vertically. The dense phase will exit the vessel through a lower exit and the light phase will exit the vessel through an upper exit. In Figure 1 the organic phase is the dense phase and the aqueous extractant is the light phase, although these roles could be switched if less dense o...

In this work we explore the deposition of gold onto a silicoaluminophosphate, using a variety of known nanoparticle deposition techniques. By comparing the gold particles deposited on a traditional microporous aluminophosphate, with an analogous hierarchical species, containing both micropores and mesopores, we explore the influence of this dual porosity on nanoparticle deposition. We show that the presence of mesopores has limited influence on the nanoparticle properties, but allows the system to maintain porosity after nanoparticle deposition. This will aid diffusion of reagents through the system, allowing continued access to the active sites in hierarchical systems, which offers significant potential in catalytic oxidation/reduction reactions.

The myriad applications of metal nanoparticle systems have individual demands on their size, shape and electronic states, demanding novel synthetic methods to optimise these properties. Herein we report our method of exploiting strong thiol-Pd binding as a precursor for forming small, uniform Pd nanoparticles on activation. We validate our approach with a range of characterisation techniques and contrast our design strategy with an analogous wetness impregnation method, showing the drastic improvements for catalytic CÀ C coupling. The presence of the thiol groups offers greater control over nanoparticle formation, particularly temperature resolution on activation, potentially allowing more targeted nanoparticle formation procedures.Metal nanoparticles (NPs) are at the forefront of modern technology in the fields of chemistry, [1] optics [2] and medicine, [3] leading the way in applications such as drug delivery, imaging and catalysis. [1a,2-3] The interest in metal NPs is due to their small size, prompting a range of unique behaviours and properties not seen in the bulk material. [4] Principally, this is due to the enhanced surface-to-volume ratio of nanoparticles, maximising the exposed 'frustrated surface', resulting in defect sites and different crystallographic planes. [5] In catalysis this maximises the surface coverage of active sites that can initiate or propagate a vast range of chemical processes. [6] Metal NPs are widely used as catalysts due to the many controllable parameters that can be tailored for specific functions, which includes nanoparticle size, shape, phase and composition. [7] One[a] Dr.

The formation of hybrid plasmonic nanocatalysts made of Au nanoparticles (NPs) combined with catalytically active NPs has gained great attention owing to their interesting properties and efficient catalysis under visible light irradiation. However, the research on the combination of plasmonic metal NPs with unique support frameworks is still limited. In this report, the varying ratio of AuxPdy prepared by the extrusion method on the CuClP framework has been correlated to its optimized catalysis in the Suzuki‐Miyaura coupling reaction in dark and under visible light irradiation. The prepared catalysts AuxPdy/CuClP were characterized by spectroscopic techniques to understand the structural and electronic modification with different metal ratios. The presence of bimetallic NPs on the surface was confirmed by HR‐TEM measurements and [MCl4]n− species in the framework were validated by XPS, FT‐EXAFS, DR UV‐Vis‐NIR, and Raman analysis. The obtained results display the superior catalytic performance and highest plasmonic enhancement factor over Au1Pd1/CuClP under visible light irradiation, which was facilely recycled and reused for several cycles. The hot‐electron transfer mechanism has been discussed for enhanced catalysis in the plasmon‐driven Suzuki−Miyaura coupling reaction. These results are highly significant in the rational design of new plasmonic photocatalysts combined with unique support materials.