Impact of Porous Silica Nanosphere Architectures on the Catalytic Performance of Supported Sulphonic Acid Sites for Fructose Dehydration to 5-Hydroxymethylfurfural

5-hydroxymethylfurfural represents a key chemical in the drive towards a sustainable circular economy within the chemical industry. The final step in 5-hydroxymethylfurfural production is the acid catalysed dehydration of fructose, for which supported organoacids are excellent potential catalyst candidates. Here we report a range of solid acid catalysis based on sulphonic acid grafted onto different porous silica nanosphere architectures, as confirmed by TEM, N2 porosimetry, XPS and ATR-IR. All four catalysts display enhanced active site normalised activity and productivity, relative to alternative silica supported equivalent systems in the literature, with in-pore diffusion of both substrate and product key to both performance and humin formation pathway. An increase in-pore diffusion coefficient of 5-hydroxymethylfurfural within wormlike and stellate structures results in optimal productivity. In contrast, poor diffusion within a raspberry-like morphology decreases rates of 5-hydroxymethylfurfural production and increases its consumption within humin formation.

Vortex fluidic mediated synthesis of polysulfone

Polysulfone (PSF) was prepared under high shear in a vortex fluidic device (VFD) operating in confined mode, and its properties compared with that prepared using batch processing. This involved reacting the pre-prepared disodium salt of bisphenol A (BPA) with a 4,4'-dihalodiphenylsulfone under anhydrous conditions. Scanning electron microscopy (SEM) established that in the thin film microfluidic platform, the PSF particles are sheet-like, for short reaction times, and fibrous for long reaction times, in contrast to spherical like particles for the polymer prepared using the conventional batch synthesis. The operating parameters of the VFD (rotational speed of the glass tube, its tilt angle and temperature) were systematically varied for establishing their effect on the molecular weight (M w), glass transition temperature (T g) and decomposition temperature, featuring gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) respectively. The optimal VFD prepared PSF was obtained at 6000 rpm rotational speed, 45° tilt angle and 160 °C, for 1 h of processing with M w ∼10 000 g mol-1, T g ∼158 °C and decomposition temperature ∼530 °C, which is comparable to the conventionally prepared PSF.

Vortex Fluidic Mediated Synthesis of Macroporous Bovine Serum Albumin-Based Microspheres

Macroporous bovine serum albumin (BSA) nanoparticles with controllable diameter were readily fabricated in a rapidly rotating angled glass tube in a vortex fluidic device (VFD). Systematically varying the rotational speed and the ratio of BSA, ethanol, and glutaraldehyde led to conditions for generating ca. 600 nm diameter macroporous particles that have intrinsic fluorescence emission at 520 nm when excited at 490 nm. The presence of the macropores increased the absorption efficiency of rhodamine B with potential applications for drug delivery purpose, compared with BSA nanoparticles having surfaces devoid of pores. Further control over the size of BSA nanoparticles occurred in the presence of C-phycocyanin protein during the VFD processing, along with control of their shape, from spheres to pockets, as established in exploring the parameter space of the microfluidic device.

Vortex Fluidic Chemical Transformations

Driving chemical transformations in dynamic thin films represents a rapidly thriving and diversifying research area. Dynamic thin films provide a number of benefits including large surface areas, high shearing rates, rapid heat and mass transfer, micromixing and fluidic pressure waves. Combinations of these effects provide an avant-garde style of conducting chemical reactions with surprising and unusual outcomes. The vortex fluidic device (VFD) has proved its capabilities in accelerating and increasing the efficiencies of numerous organic, materials and biochemical reactions. This Minireview surveys transformations that have benefited from VFD-mediated processing, and identifies concepts driving the effectiveness of vortex-based dynamic thin films.

Vortex fluidics synthesis of polymer coated superparamagnetic magnetite nanoparticles

Polymer coated superparamagnetic magnetite nanoparticles with improved magnetic properties are accessible under continuous flow conditions within a vortex fluidic device.

Fluid dynamic lateral slicing of high tensile strength carbon nanotubes

Lateral slicing of micron length carbon nanotubes (CNTs) is effective on laser irradiation of the materials suspended within dynamic liquid thin films in a microfluidic vortex fluidic device (VFD). The method produces sliced CNTs with minimal defects in the absence of any chemical stabilizers, having broad length distributions centred at ca 190, 160 nm and 171 nm for single, double and multi walled CNTs respectively, as established using atomic force microscopy and supported by small angle neutron scattering solution data. Molecular dynamics simulations on a bent single walled carbon nanotube (SWCNT) with a radius of curvature of order 10 nm results in tearing across the tube upon heating, highlighting the role of shear forces which bend the tube forming strained bonds which are ruptured by the laser irradiation. CNT slicing occurs with the VFD operating in both the confined mode for a finite volume of liquid and continuous flow for scalability purposes.

Towards aryl C-N bond formation in dynamic thin films

C-N bond forming reactions are important in organic chemistry. A thin film microfluidic vortex fluidic device (VFD) operating under confined mode affords N-aryl compounds from 2-chloropyrazine and the corresponding amine, without the need for a transition metal catalyst.

Shear induced fabrication of intertwined single walled carbon nanotube rings

Thin film microfluidic shearing of a mixture of toluene dispersed single walled carbon nanotubes (SWCNTs) and water in a vortex fluidic device results in SWCNT nanorings (and related structures), diameters 100 to 200 nm or 300 to 700 nm, for respectively 10 mm or 20 mm diameter rotating tubes.

Room temperature vortex fluidic synthesis of monodispersed amorphous proto-vaterite

Monodispersed particles of amorphous calcium carbonate (ACC) 90 to 200 nm in diameter are accessible at room temperature in ethylene glycol and water using a vortex fluidic device (VFD). The ACC material is stable for at least two weeks under ambient conditions.

Nitrate uptake using mesoporous silica embedded with zero-valent palladium nanoparticles

In situ reduction of palladium(ii) acetylacetonate during the synthesis of SBA-15 mesoporous silica affords material impregnated with palladium nanoparticles, with the material being effective for nitrate-nitrogen removal.

Continuous flow Fischer esterifications harnessing vibrational-coupled thin film fluidics

Organic synthesis under shear: high yielding, acid catalysed, continuous flow synthesis of esters involves coupling of vibrations in thin film fluidics, as rapid environmentally friendly organic methodology.

Microencapsulation of bacterial strains in graphene oxide nano-sheets using vortex fluidics

Microencapsulation of bacterial cells with different shapes in graphene oxide (GO) layers is effective using a vortex fluidic device, with the bacterial cells showing restricted cellular growth with their biological activity sustained.

Continuous flow vortex fluidic synthesis of silica xerogel as a delivery vehicle for curcumin

Sol–gel synthesis of silica xerogel using a continuous flow vortex fluidic device at room temperature is effective in direct incorporation of preformed curcumin particles, which has antimicrobial activity against Staphylococcus aureus.

Photoredox catalysis under shear using thin film vortex microfluidics

A microfluidic vortex fluidic device (VFD) operating in either confined or continuous mode is effective in high yielding photoredox reactions involving Rose Bengal, with short reaction times.

Spinning up the polymorphs of calcium carbonate

Controlling the growth of the polymorphs of calcium carbonate is important in understanding the changing environmental conditions in the oceans. Aragonite is the main polymorph in the inner shells of marine organisms, and can be readily converted to calcite, which is the most stable polymorph of calcium carbonate. Both of these polymorphs are significantly more stable than vaterite, which is the other naturally occurring polymorph of calcium carbonate, and this is reflected in its limited distribution in nature. We have investigated the effect of high shear forces on the phase behaviour of calcium carbonate using a vortex fluidic device (VFD), with experimental parameters varied to explore calcium carbonate mineralisation. Variation of tilt angle, rotation speed and temperature allow for control over the size, shape and phase of the resulting calcium carbonate.

Continuous flow vortex fluidic production of biodiesel

Vortex fluidic synthesis of biodiesel from sunflower oil under continuous flow at room temperature, with spontaneous phase separation.