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Growing concern about the supply of goods under the COVID pandemic due to border restrictions and community lockdown has made us aware of the limitations of the global supply chain. Fertilisers are pivotal for the growth and welfare of humankind and there is more than a century history in industrial technology. Ammonia is the key platform chemical here which can be chemically diversified to all kinds of fertilisers. This paper puts a perspective on production technologies that can enable a supply of ammonia locally and on-demand in Australia, for the farmers to produce resilient and self-sustained fertilisers. To assess the validity of such a new business model, multi-objective optimisation has to be undergone, and computing is the solution to rank the millions of possible solutions. In this lieu, an economic optimisation framework for the Australian ammonia supply chain is presented. The model seeks to address the economic potential of distributed ammonia plants across Australia. Different techniques for hydrogen and related ammonia production such as thermal plasma, non-thermal plasma, and electrolysis (all typifying technology-disruption), and mini Haber-Bosch (typifying scale-disruption) are benchmarked to the central mega plant on a world-scale using conventional technology; verifying that ‘Moore’s Law’1 of growing bigger and bigger is not the only path to sustainable agriculture. Results show that ammonia can be produced at $317/ton at a regional scale using thermal plasma hydrogen generation which could be competitive to the conventional production model, if credit in terms of lead time and carbon footprint could be taken into account.

The paper compares conceptual designs of a microstructured reactor/heat-exchanger for the small-scale production of C8+ range hydrocarbons from methanol over H-ZSM-5 catalytic coatings. In these designs, air was used as a cooling fluid in the adjacent cooling channels. The heat transfer characteristics of a single-zone reactor (with channels 500 μm in diameter) and a two-zone reactor (with an additional coolant inlet) have been compared. A single reaction zone was not able to reduce the temperature gradient below 15 K, while a two-zone configuration, with a counter-current fluid flow in the upstream section and co-current flow in the downstream section, demonstrated a near-isothermal behaviour, with a mean temperature of 653 K.

The magnetic enrichment behavior of monodispersed MFe2O4 (M = Mg, Ca, Ni, Co, and Cu) ferrite nanoparticles with different size (10–130 nm) on the surface of a 15 mm o.d. NdFeB-N40 magnetic rod has been investigated. The materials were synthesized by a modified sol-gel method. They were characterized by XRD, TEM, and VSM. The magnetic field of the rod was modelled numerically using a finite element analysis software to obtain the input data for the magnitude of magnetic force. Three adsorption models can be used to describe the enrichment mechanism of ferrite nanoparticle depending on the magnetic permeability: (i) Freundlich adsorption model at low magnetic permeability ( 100 μemu/Oe) leading to the enrichment percentage above 90%.

By using a multispecies fluid model, the tunability and controllability of plasma parameters such as distributions of electron density, electron energy, ion density, and electric field in a microdielectric barrier discharge (DBD) with a charge injector electrode and driven by negatively polarized nanosecond pulsed voltage superimposed on a positive DC bias voltage are investigated. To this end, the effects of changing features of pulsed voltage like pulse rise time (10-20 ns), pulse peak width (10-15 ns), and pulse fall time (20-30 ns) on characteristics of argon plasma formed inside the reactor are studied. The results show that with the increase in pulse width and pulse rise time, the density of electron and ion increases, while fall time change does not significantly affect the plasma parameters. Generally, the results of this study explicitly prove the possibility of controlling plasma formed inside DBD reactors driven by negative pulse voltage combined with a positive DC voltage, which is very important in waste gas conversion applications.

Six of the most promising lab-scale synthesis process methodologies for N-doped carbon dots (NCDs) are selected and compared in terms of green chemistry and circular and EcoScale/Good-Manufacturing-Practice metrics. We compare a new innovative route, the low-temperature plasma-enabled synthesis of carbon dots, e.g., from citric acid and monoethanolamine, to more-established literature processes, such as thermochemical processes, from the same or other materials. Along with this study, the advantages and disadvantages of each method are depicted in manifold sustainability facets. It is shown how recycling/reuse of nonconverted starting materials and solvents can improve the sustainability profile. In addition, safety constraints, cost analysis, and energy consumption are considered. The analysis showed that the thermal process from citric acid and monoethanolamine gives the best performance with regard to the sustainability assessment chosen here. It has a material circularity indicator of 0.971, with an EcoScale factor of 56% and an E-factor of 5.56. In continuation of those results, the paper shows how the low-temperature plasma using the same materials and the same recycling strategy can be improved to come closer to the performance of its thermal counterpart. It has the best energy efficiency, while lacking so far in mass efficiency. From this study, we learned more about which of these methods are most promising for scaling-up and industrial manufacturing of N-doped carbon dots.

As an ideal hydrogen production route, electrolyzed water still faces the challenges of high cost of noble-metal electrocatalysts and low performance of non-noble-metal catalysts in scalable applications. Recently, introduction of external fields (such as magnetic fields, light fields, etc.) to improve the electrocatalytic water splitting performance of non-noble-metal catalysts has attracted great attention due to their simplicity. Here, a simple method for preparing magnetic superstructure (NiFe2O4@MOF-74) is described, and the hydrogen evolution reaction (HER) behavior of its carbonized derivative, a ferromagnetic superstructure, is revealed in a wide range of applied voltage under an AC magnetic field. The overpotential (@10 mA cm–2) required for the HER of the obtained ferromagnetic superstructure in 1 M KOH was reduced by 31 mV (7.7%) when a much small AC magnetic field (only 2.3 mT) is applied. Surprisingly, the promotion effect of the AC magnetic field is not monotonically increasing with the increase of the applied voltage or the strength of AC magnetic field, but increasing first, then weakening. This unusual behavior is believed to be mainly caused by the enhanced induced electromotive force and the additional energy by the applied AC magnetic field. This discovery provides a new idea for adjusting the performance of electrocatalytic reactions.\ud \ud

Quality by Design encouraged by the US Food and Drug Administration (FDA) in the continuous flow synthesis requires tight monitoring of all the reaction input and output parameters to improve reproducibility and eliminate the process rejects. The reaction monitoring, however, relies on costly (above 10,000$) process analytical technology (PAT) – one of the factors that prevents a wider utilisation of continuous processes. In the work, we show that gas-liquid reactions can be monitored using low-cost (10$) hardware – optical liquid inline sensors – that allows instantaneous analysis of gas fraction in the moving stream. We discuss the application of the sensor for various gas-liquid reactions. The gas-consuming reactions such as hydrogenation are the easiest to implement because the sensor without calibration provides accurate readings close to complete consumption of the gas. The gas-evolving reactions can be monitored but require sensor calibration to determine the gas fraction accurately. Operation of the sensor was demonstrated for various hydrogenation reactions self-optimised using a proportional-integral (PID) algorithm which adjusted the substrate concentration to provide high (but not full) pre-defined hydrogen consumption. The optimised hydrogen consumption agreed with the product analysis for a range of the substrates hydrogenated under various pressures and with different selectivities. The optical sensor was also proven to be an efficient tool in adapting the reaction condition to the catalyst deactivation in the reaction of 2-methyl-3-butyn-2-ol semi-hydrogenation – the autonomous reactor allowed reaching a turn-over number (TON) of 2.7·106 with the value of 1.5·107 expected till a twofold decrease in the catalyst activity. The TON values demonstrated are significantly higher than those observed in batch reactors (~103) even in case of catalyst re-use (105) demonstrating a substantial improvement of process sustainability operating with the process control.\ud \ud

With the development of power electronics, metallizing of ceramics has been developed and employed in many industrial applications. This paper describes the effect of porosity, mean pore size and glass phase content of Al2O3 substrate on the microstructure evolution and mechanical properties of metallized ceramics obtained by an activated Mo–Mn method. The interface reaction as well as the joining strength between Al2O3 ceramic and Mo–Mn layer were investigated systematically using X-ray diffraction, SEM, energy dispersive X-ray analysis et al. The overall porosity affects the ‘absorptivity’ of the substrate towards the glass phase in the metallized layer, while the glass phase content affects the diffusion depth of the Mn-containing phase. The results show that the distribution of the Mn-containing glass phase in the alumina substrate determined the failure characteristics of specimens under bending and tension conditions. The mean pore size determines the magnitude of capillary force responsible for the diffusion of Mn-containing glass phase into the ceramic substrate. The thickness of the Mo–Mn layer reduced and the thickness of the transition region increased at high alumina porosity. This resulted in a decrease of tensile strength, and an increase of flexural strength growth rate GR for specimens after metallization. The tensile strength of metallized specimens monotonously increased with the glass phase content, while the flexural strength first increased and then decreased. A tensile strength of 1990 ± 75 N, a flexural strength of 9499 ± 346 N and a He leakage rate of 3.5 × 10−11 Pa m3 s−1 were obtained in the optimized specimens after metallization.

In this work, the Co0.5Zn0.5Fe2O4 microtube was prepared via a template-assembled sol–gel method, where three kinds of natural fiber worked as template. Effect of template types on morphology, specific area, and magnetic properties under different temperatures of ferrites microtube was investigated. XRD results confirm the formation of pure spinel Co0.5Zn0.5Fe2O4; SEM results proves that the CZF-microtubes is mono-dispersed and exactly copies the morphology of the corresponding template. It possesses excellent magnetic properties (Ms, 62.62 emu g−1) and higher specific area (51.11 m2 g−1), respectively, the former is mainly due to the net-liked microstructure and distribution of higher magnetic magneton cation in crystal cell, and the latter is attributed to not only the smaller grain size, but also the stack manner of nanoparticles. Below Curie temperature, coercivity of CZF-microtubes decreases with an increased temperatures in accordance with the ferromagnetism theory as the degree of atomic thermal vibration increases; Above Curie temperature, the unique variety of coercivity is attributable to not only the competition between the 2nd and 4th order crystal field terms derived from the d electrons of Fe3+ and Co2+ in crystal cell, but also the easy magnetized direction switches from basal plane to c axis via a preferred orientation of the magnetic moments in microtubes structure; The high Hc value of CZF-microtube above Blocking temperature TB (450.19 K) results from the existence of interparticle interaction as nanoparticles of it aggregate to produce a microtube structure, and resulting in a deviation from normal Kneller’s law.

Structured microchannel H-ZSM-5 catalysts containing up to 80 wt% zeolite (balance bentonite) were fabricated by unit operations of paste preparation, extrusion, drying and firing. The structured catalysts, called miniliths due to their micrometre-range dimensions, were composed of parallel cylindrical channels with a wall thickness of 200–300 μm, density of 2.1 channels/mm2 and a channel diameter of 300 μm. These miniliths were characterised by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, N2 physisorption and thermogravimetric analysis. For the first time, these miniliths were tested for the conversion of methanol to gasoline at 370 °C, 3 bar and a weight hourly space velocity (WHSV) of up to 1170 h−1. A gasoline product yield of 53% was obtained at a methanol conversion of 74% over the ZSM-5 miniliths. The pressure drop at the same conversion over a packed-bed reactor of equal ZSM-5 content was 2 orders of magnitude higher than that of the minilith. Reducing the amount of ZSM-5 catalyst in the packed bed, to obtain similar inlet pressure as the ZSM-5 minilith gave the same product yield at a much higher conversion (81%) demonstrating the potential of these structured microchannel reactors.

The desorption of methanol and dimethyl ether has been studied over fresh and hydrocarbon-occluded ZSM-5 catalysts with Si/Al ratios of 25, 36 and 135 using a Temporal Analysis of Products (TAP) reactor. The catalysts were characterized by XRD, SEM, N2 physisorption and pyridine FT-IR. The crystal size increases with Si/Al ratio from 0.10 to 0.78 µm. The kinetic parameters were obtained using the Redhead method and a plug flow reactor model with coupled convection, adsorption and desorption steps. ZSM-5 catalysts with Si/Al ratios of 25 and 36 exhibit three adsorption sites (low, medium, and high temperature sites), while there is no difference between medium and high temperature sites at a Si/Al ratio of 135. Molecular adsorption on the low temperature site and dissociative adsorption on the medium and high temperature sites give a good match between experiment and the plug flow reactor model. The DME desorption activation energy was systematically higher than that of methanol. Adsorption stoichiometry shows that methanol and DME form clusters onto the binding sites. When non-activated re-adsorption is accounted for, a local equilibrium is reached only on the low and medium temperature binding sites. No differences were observed, other than in site densities, when extracting the kinetic parameters for fresh and activated ZSM-5 catalysts at full coverage.

Liquid-phase hydrogenation of a solution of furfural, phenol and acetic acid has been studied in the 50–235 °C range over magnetic Ru/Fe 3 O 4 -SiO 2 catalyst targeting the renewable production of second generation biofuels with minimum hydrogen consumption. Phenol was fully hydrogenated to cyclohexanol in the entire temperature range. Below 150 °C, furfural was mainly hydrogenated to tetrahydrofurfuryl alcohol while hydrogenolysis to cyclopentanol was the main reaction pathway above 200 °C. The hydrogenation rate was doubled in an acidic solution (pH = 3) as compared to that at a pH 6. The spent catalyst was regenerated and reused in subsequent catalytic runs.

An approach for analysis of thermal gradients in a catalytic packed bed milli-reactor operated under radio frequency (RF) heating has been presented. A single-point temperature measurement would cause the misinterpretation of the catalytic activity in an RF-heated reactor, because of the presence of a temperature gradient. For reliable data interpretation, the temperature should be measured at three positions along the reactor length. The temperature profile can be accurately estimated with the exact analytical solution of a one-dimensional (1D) convection and conduction heat-transfer model, and it can also be approximated with a second-order polynomial function. The results revealed that the position of maximum temperature in the catalytic bed shifts toward a downstream location as the flow rate increases. The relative contribution of conduction and convection to the overall heat transport has been discussed. The design criteria for a near-isothermal milli-reactor have been suggested.\ud \ud

This work is devoted to the investigation of the possibility of the use of Ru-containing catalysts on the basis of polymeric matrix of hypercrosslinked polystyrene (HPS) in the hydrogenation of levulinic acid (LA) to gamma-valerolactone (GVL). HPS-based Ru-containing catalysts were synthesized at variation of HPS type (MN100 bearing amino groups or MN270 without functional groups) and metal content. Catalyst 5%-Ru/MN100 was shown to compete with commercial 5%-Ru/C and to allow carrying out the hydrogenation of LA in aqueous medium with high yields of GVL (more than 99%).

Catalyst-coated tube reactors have been compared with the reactors packed with catalyst powder in alkyne semi-hydrogenation over a 5 wt% Pd/ZnO catalyst and cinnamic ester full hydrogenation over a 2.4 wt% Pd/C catalyst. The “powder packed-bed” reactors (packing with catalyst powder below 30 μm) showed irreproducible performance in time due to mobility of the catalyst layer in the bed which altered the fluidic path and therefore affected the mean liquid residence time and the dispersion. The catalyst-coated tube reactors demonstrated an ideal plug-flow behaviour (Peclet number > 120), while the powder packed-bed showed a considerable back-mixing (Peclet ~ 25). Under all conditions studied, the reaction rate in the powder packed-bed was limited by external mass transfer, while in the coated tube – by the intrinsic kinetics. The coated tubes demonstrated a much lower pressure drop, an improved alkene selectivity, and a 5 times higher throughput compared to the powder packed-bed. The dilution of the catalyst bed with glass beads improved the throughput 4-fold at the expense of 4-fold increase in the pressure drop. In full hydrogenation reaction, the catalyst-coated tube showed a 14 times higher throughput than in the powder packed-bed at the full alkyne conversion. A reactor model for the catalyst-coated tube has been proposed that takes into account the change in the fluid velocity during the reaction. The model described the reaction kinetics demonstrating that the catalyst-coated tubes can be used as a tool to obtain kinetic data in gas-liquid reactions in flow.

The study presents the results of cellulose hydrolytic hydrogenation process in subcritical water in the presence of Ru-containing catalysts based on hypercrosslinked polystyrene (HPS) MN-270 and its functionalized analogues: NH2-HPS (MN-100) and SO3H-HPS (MN-500). It was shown that the replacement of the traditional support (carbon) by HPS increases the yield of the main cellulose conversion products – polyols – important intermediates for the chemical industry. The catalysts were characterized using transmission electron microscopy (TEM), high resolution TEM, and porosity measurements. Catalytic studies demonstrated that the catalyst containing 1.0% Ru and based on MN-270 is the most active. The total yield of sorbitol and mannitol was 50% on the average at 85% cellulose conversion.

Many catalytic applications use conventional heating to increase the temperature to allow the desired reaction. A novel methodology is presented for the preparation of magnetic zeolite-based catalysts, allowing more efficient radiofrequency heating. These nanoreactors are tested in the isomerisation of citronellal with successful results and without any apparent deactivation. We thank the MINECO, GV, and FEDER (Projects CTQ2015-66080-R MINECO/FEDER, BES-2013-063678 and PROMETEOII/2014/010) for financial support. Moreover, the financial support provided by the European Research Council (ERC), project 279867, and Russian Science Foundation (project 15-13-20015) is gratefully acknowledged.

The effect of periodic changes in particle velocity on mass transfer to the reacting surface of a magnetic particle with a diameter 225 μm in laminar flow has been investigated in a microfluidic reactor. The periodic particle motion in a fluid was investigated under a sinusoidal magnetic field generated by a quadrupole arrangement of electromagnets around the reactor. The effect of operating frequency of the rotating magnetic field, intensity of the magnetic field, and phase shift between the two sets of magnets on particle dynamics has been studied. Three particle motion modes have been observed depending on the frequency of the applied field. The mass transfer rate was estimated under steady velocity and variable velocity of the particle using a mass transfer correlation by Feng and Michaelides (2001). The validity of this correlation for the case of variable particle velocity has been confirmed with a 2D numerical model, describing actual hydrodynamics and mass transfer towards the particle surface. The mass transfer coefficient depends both on the mean particle velocity and the deviation of velocity from the mean value. The periodic movement with variable particle velocity reduces the mass transfer coefficient by 7.6% as compared to steady state motion with the same mean velocity.\ud \ud

A 2.5 wt.% Pd/ZnO catalytic coating has been deposited onto the inner wall of capillary reactors with a diameter of 0.53 and 1.6 mm. The coatings were characterised by XRD, SEM, TEM and elemental analysis. The performance of catalytic reactors was studied in solvent-free hydrogenation of 2-methyl-3-butyn-2-ol. No mass transfer limitations was observed in the reactor with a diameter of 0.53 mm up to a catalyst loading of 1.0 kg(Pd) m−3. The activity and selectivity of the catalysts has been studied in a batch reactor to develop a kinetic model. The kinetic model was combined with the reactor model to describe the obtained data in a wide range of reaction conditions. The model was applied to calculate the range of reaction conditions to reach a production rate of liquid product of 10–50 kg a day in a single catalytic capillary reactor.

One-dimensional isolated Ni0.5Zn0.5Fe2O4 microtubes have been prepared via a template assisted sol–gel method. Temperature dependence of the structural and magnetic properties was studied via XRD, N2 adsorption, SEM, TEM, and VSM. An increase in calcination temperature from 873 to 1273 K caused a decrease in the specific surface area from 80.7 to 17.0 m2/g due to an increase of the grain size from 25.3 to 112 nm. All samples demonstrated anomalous coercivity behavior due to mechanical stresses acting on their domain walls. The porous microtubes calcined at 1073 K have a mean external diameter of 3.7 μm with a length-to-diameter ratio exceeding 12. The microtubes calcined at 973 K have the highest coercivity of 88.1 Oe and demonstrated the largest specific heating rate of 4.36 W/g in a radiofrequency field at 295 kHz.

A new approach was proposed for the preparation of metal–organic framework/metal oxide composites in one step using only metal salts. Here, crystalline rhombohedral dodecahedron ZIF-8, hollow ZnO microsphere, and ZIF-8/ZnO composites were obtained in different one-pot solvothermal processes where the growth toward individual ZIF-8 and ZnO phases and toward ZIF-8/ZnO composites was controlled by adjusting the ratio of metal salts to 2-methylimidazole. Subsequently, a series of derived (C and/or N)-doped ZnO nanoparticles was obtained by a two-step calcination process. The absorption kinetics and photocatalytic activity in methyl orange degradation under visible light were investigated. ZIF-8-derived ZnO could maintain their original morphology and displayed excellent photocatalytic activity 10 times higher than that of the original ZIF-8.

Catalysts consisting of Pt and Cu supported on Mo2C/η-Al2O3, Mo2C/γ-Al2O3 or Mo2C were prepared and used for the low-temperature water gas shift reaction (WGSR). The catalysts were characterized by elemental analysis, powder X-ray diffraction (XRD), temperature-programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The catalysts were studied in water gas shift reaction with a reaction mixture containing 11% CO, 43% H2, 6% CO2, 21% H2O (real feed composition mixture from the reformer) and balance He, with a reaction temperature range of 180–300 °C at a space velocity (SV) of 125,000 h−1. Catalyst supports (η-Al2O3 and γ-Al2O3), led to different synergetic effect between the two most active phases of Pt metal and Mo2C. Pt/Mo2C/η-Al2O3 is a promising catalyst (44% conversion at 180 °C) due to the close interaction between Pt and Mo2C phases on the surface of the catalyst. The 4 wt% Pt-Mo2C showed the highest activity where the temperature at which 50% conversion observed was at only 180 °C with SV of 125,000 h−1 and constant stability over 85 h.

The methanol-to-hydrocarbon (MTH) reaction has received considerable attention as utilizing renewable sources of both value-added chemicals and fuels becomes a number one priority for society. Here, for the first time we report the development of hierarchical zeolites (ZSM-5) containing both iron oxide and nickel oxide nanoparticles. By modifying the iron oxide (magnetite, Fe3O4) amounts, we are able to control the catalyst activity and the product distribution in the MTH process. At the medium Fe3O4 loading, the major fraction is composed of C9–C11 hydrocarbons (gasoline fraction). At the higher Fe3O4 loading, C1–C4 hydrocarbons prevail in the reaction mixture, while at the lowest magnetite loading the major component is the C5–C8 hydrocarbons. Addition of Ni species to Fe3O4–ZSM-5 leads to the formation of mixed Ni oxides (NiO/Ni2O3) positioned either on top of or next to Fe3O4 nanoparticles. This modification allowed us to significantly improve the catalyst stability due to diminishing coke formation and disordering of the coke formed. The incorporation of Ni oxide species also leads to a higher catalyst activity (up to 9.3 g(methanol)/(g(ZSM-5) × h)) and an improved selectivity (11.3% of the C5–C8 hydrocarbons and 23.6% of the C9–C11 hydrocarbons), making these zeolites highly promising for industrial applications.

Core-shell composite magnetic catalysts TiO2@NiFe2O4 with a titania loading of 9–32 wt. % have been synthesised by sol-gel method for direct amide synthesis in a radiofrequency (RF)-heated continuous flow reactor. The catalyst calcination temperature was optimised in the range of 350-500 ºC and the highest activity was observed for the catalyst calcined at 500 ºC due to conversion of titania into catalytically active anatase phase. No reaction between the magnetic core and the titania shell was observed up to the calcination temperature of 1000 ºC and no sintering of titania shell was observed after calcination at 500 ºC. The comparison of direct amide synthesis in a continuous flow fixed bed reactor under conventional and RF heating demonstrated that the RF heating mode increased the apparent reaction rate by 60 % and decreased the deactivation rate due to a better temperature uniformity. The titania weight normalised reaction rate in the RF-heated reactor was constant for titania loadings above 17 wt. %, while it decreased by a factor of 3 at lower titania loadings because of interactions between the ferrite core on the thin layer of the catalyst. The catalyst deactivation study showed that the deactivation rate could be accurately described by a first order kinetics and that the main reason of deactivation was coking. The catalyst regeneration via calcination at 400 ºC resulted in the catalyst sintering, while a treatment with a hydrogen peroxide solution at 90 ºC fully recovered catalytic activity.

Composite NiFe2O4–TiO2 magnetic catalysts were prepared by mechanochemical synthesis from a mixture of titania supported nickel ferrite nanoparticles and P25 titania (Evonic). The former provides fast and efficient heating under radiofrequency field, while the latter serves as an active catalyst or catalyst support. The highest heating rate was observed over a catalyst prepared for a milling time of 30 min. The catalytic activity was measured over the sulfated composite catalysts in the condensation of aniline and 3-phenylbutyric acid in a stirred tank reactor and in a continuous RF heated flow reactor in the 140–170 °C range. The product yield of 47% was obtained over the sulfated P25 titania catalyst in the flow reactor.

In this paper, the commercial 5%Pd/C and 5%Pt/C catalysts and synthesized 5%Pt/MN-270 and 5%Pd/MN-270 were used in the hydrogenolysis of lignocellulosic material (softwood sawdust) to obtain liquid fuels in the form of hydrocarbons. As lignin has a very complex structure, anisole was used as a model compound. It was found that the use Pt-containing catalysts based on hypercrosslinked polystyrene in both processes of anisole and lignin-containing feedstock conversion allowed obtaining the highest yield of oxygen-free hydrocarbons (up to 96 wt. %). Besides, the polymer based catalysts showed high stability in hydrogenolysis process in comparison with the commercial carbon based catalysts. Copyright © 2018 BCREC Group. All rights reservedReceived: 3rd March 2017; Revised: 18th August 2017; Accepted: 21st August 2017; Available online: 22nd January 2018; Published regularly: 2nd April 2018How to Cite: Shimanskaya, E.I., Stepacheva, A.A., Sulman, E.M., Rebrov, E.V., Matveeva, V.G. (2018). Lignin-containing Feedstock Hydrogenolysis for Biofuel Component Production. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (1): 74-81 (doi:10.9767/bcrec.13.1.969.74-81)

A novel continuous flow process for selective hydrogenation of α, β-unsaturated aldehyde (cinnamaldehyde, CAL) to the unsaturated alcohol (cinnamyl alcohol, COL) has been reported in a tube reactor coated with a Pt/SiO2 catalyst. A 90% selectivity towards the unsaturated alcohol was obtained at the aldehyde conversion of 98.8%. This is a six-fold improvement in the selectivity compared to a batch process where acetals were the main reaction products. The increased selectivity in the tube reactor was caused by the suppression of acid sites responsible for the acetal formation after a short period on stream in the continuous process. In a fixed bed reactor, it had a similar acetal suppression phenomenon but showed lower product selectivity of about 47–72% due to mass transfer limitations. A minor change in selectivity and conversion caused by product inhibition was observed during the 110 h on stream with a turnover number (TON) reaching 3000 and an alcohol production throughput of 0.36 kg gPt−1 day−1 in the single tube reactor. The catalysts performance after eight reaction cycles was fully restored by calcination in air at 400 °C. The tube reactors provide an opportunity for process intensification by increasing the reaction rates by a factor of 2.5 at the reaction temperature of 150 °C compared to 90 °C with no detrimental effects on catalyst stability or product selectivity.

A series of TiO2@SiO2@NiFe2O4 composite magnetic catalyst with a core-double shell structure was synthesized by a sol-gel method. The morphology of the catalysts was studied by XRD, SEM, N2 physisorption and their magnetic properties were examined with magnetometry, and specific absorption rate measurements. The catalytic activity was determined in a direct amide synthesis reaction between aniline and phenylbutyric acid at 150 °C in a fixed bed flow reactor under radiofrequency heating. The intermediate silica layer of the catalyst increased the porosity of the outer titania layer and the specific absorbance rate of the catalyst. The initial reaction rate increased by 61% as compared to a similar core-shell TiO2@NiFe2O4 catalyst showing the detrimental effect of nickel ferrite on titania. The reaction rate was further increased by a factor of 3.5 after a sulfation treatment due to an optimum Lewis acid site strength. The highest specific reaction rate over TiO2@SiO2@NiFe2O4 was observed at a 7.5 wt% sulfate loading which was 2.6 times higher as compared to a mechanical mixture of the same composition. The initial reaction rate decreased by 36% after a period of 55 h on stream. The catalyst activity was restored after a treatment with a H2O2 solution.\ud

A parametric study of the factors that influence C–O bond formation reactions has been carried out to elucidate the mechanism by which copper mediates the Ullmann-type nucleophilic aromatic substitution (SNAr) of 4-chloropyridine with potassium phenolate. Process conditions such as temperature, reactant concentrations, catalyst concentration, and amounts of solubilizing additive were varied to obtain the kinetic data. Both reactant and product concentration were found to have a significant effect on the reaction rate. An increased concentration of 18-crown-6 ether, used as an alkali metal solubilizing agent for potassium phenolate, proved to be effective only for low conversions, whereas an inhibited phenolate complexation at high product concentrations was observed. An apparent activation energy of 55 kJ·mol–1 was observed for a Cu0 catalyst in the liquid-phase coupling reaction in a temperature range of 100–150 °C. It was demonstrated that a Langmuir–Hinshelwood kinetic model is mechanistically most lik...

A series of Sr2−xNdxNi2 Fe28−yCoyO46 (x = 0.02, 0.04, 0.06, 0.08, 0.10 and y = 0.1, 0.2, 0.3, 0.4, 0.5) X-type hexagonal ferrites has been prepared by sol–gel method at 1250 °C for 6 h. XRD analysis shows the single phase of the prepared ferrites material. The lattice constant values and c/a ratio shows that the present assembled material belongs to the family X-type hexagonal ferrites. The peaks in the FTIR spectra are the characteristics of the hexagonal ferrites. The crystallite size measured by Scherer formula is in good agreement with the crystallite size measured by TEM and HRTEM. The enhancement in the magnetic properties can easily be observed with the doping of rare earth element Nd3+ and divalent Co2+. Due to high saturation and low coercivity values the present material can be good microwave absorber. The temperature dependent saturation and remanance magnetization decreases monotonically with temperature. The minimum value of reflection loss enhances with the substituent and the attenuation constant results are in agreement with reflection loss results.

This review provides a general overview of recent applications of magnetic nanoparticles for controlled radiofrequency (RF) heating in catalytic synthesis, mass transfer enhancement in laminar fl ow and magnetic separation. By directly delivering RF energy to magnetic materials, issues such as long heating periods and energy losses can be minimized. The main mechanisms of RF heating are briefl y reviewed. The effect of nanoparticles size, shape and composition on the effi ciency of RF heating is discussed. RF energy has been shown to be effective in many applications, however, it is still not used in chemicals due to high equipment costs.

A new two-stage synthesis of double molybdenum and nickel carbides and high-activity and stable catalytic coatings of nickel-promoter molybdenum carbides in salt melts is developed. The first stage includes the formation of molybdenum-nickel alloys by an electrolytic method and currentless transfer in chloride melts. The second stage consists in the carbonization of the alloys in a chloride-carbonate melt under various synthesis conditions. The stabilities of the nickel-promoter catalytic systems are studied, and their catalytic activities in the back water-gas shift reaction are determined.

Joule heat-induced hot-spot formation sets severe limits in the operation of continuous annular electrochromatography (CAEC), a new concept for preparative separation as an analog to analytical capillary electrochromatography (CEC). This may lead to eluent flow perturbance, even to boiling, which would massively weaken separation efficiency and may even hamper the stationary phase used for separation. For reasons of system integration and high-efficiency heat transfer, micro flow heat exchangers are considered with a separate coolant flow. A 3D numerical analysis of the heat transfer of water single-phase laminar flow in a square microchannel and different arrays of micro pin-fins was carried out using COMSOL Multiphysics. Several advanced materials with low electric conductivity and at the same time with high heat conductivity were put forward to be used in the CAEC system. As essential design point, it is proposed to constitute the micro heat exchanger from two different parts of the CAEC system, namely a micro-structured pin-fins plate and a so-called conductive plate.

The action of nanoparticulate copper catalysts with a mean particle size of 10 nm in the Ullmann ether synthesis is reported using multimode microwave heating and employing stable chloropyridine salts and unactivated phenol, with stabilized copper nanoparticles outperforming other copper catalysts in terms of stability and reusability.

Semihydrogenation of 2-methyl-3-butyn-2-ol (MBY) was studied in a 5 m tube reactor wall-coated with a 5 wt% Pd/ZnO catalyst. The system allowed for the excellent selectivity towards the intermediate alkene of 97.8 ± 0.2% at an ambient H2 pressure and a MBY conversion below 90%. The maximum alkene yield reached 94.6% under solvent-free conditions and 96.0% in a 30 vol % MBY aqueous solution. The reactor stability was studied for 80 h on stream with a deactivation rate of only 0.07% per hour. Such a low deactivation rate provides a continuous operation of one month with only a two-fold decrease in catalyst activity and a metal leaching below 1 parts per billion (ppb). The excellent turn-over numbers (TON) of above 105 illustrates a very efficient utilisation of the noble metal inside catalyst-coated tube reactors. When compared to batch operation at 70 °C, the reaction rate in flow reactor can be increased by eight times at a higher reaction temperature, keeping the same product decomposition of about 1% in both cases.

A near-isothermal micro-trickle bed reactor operated under radio frequency heating was developed. The reactor bed was packed with nickel ferrite micro-particles of 110 μm diameter, generating heat by the application of RF field at 180 kHz. Hydrodynamics in a co-current configuration was analysed and heat transfer rates were determined at temperature ranging from 55 to 100 °C. A multi-zone reactor bed of several heating and catalytic zones was proposed in order to achieve near-isothermal operations. Exact positioning, number of the heating zones and length of the heating zones composed of a mixture of nickel ferrite and a catalyst were determined by solving a one dimensional model of heat transfer by conduction and convection. The conductive losses contributed up to 30% in the total thermal losses from the reactor. Three heating zones were required to obtain an isothermal length of 50 mm with a temperature non-uniformity of 2 K. A good agreement between the modelling and experimental results was obtained for temperature profiles of the reactor.

A series of nanostructured Ni–Zn ferrites Ni 1− x Zn x Fe 2 O 4 ( x =0, 0.5 and 1) with a grain size from 24 to 65 nm have been prepared with a sol–gel method. The effect of composition and sintering temperature on morphology, magnetic properties, Curie temperature, specific heating rate at 295 kHz and hysteresis loss have been studied. The highest coercivity of 50 and 40 Oe, were obtained for NiFe 2 O 4 and Ni 0.5 Zn 0.5 Fe 2 O 4 samples with the grain size of 35 and 29 nm, respectively. The coercivity of Ni and Ni–Zn mixed ferrites decreased with temperature. The Bloch exponent was 1.5 for all samples. As the grain size increased, the Curie temperature of NiFe 2 O 4 increased from 849 to 859 K. The highest saturation magnetization of 70 emu/g at 298 K and the highest specific heating rate of 1.6 K/s under radiofrequency heating at 295 kHz were observed over NiFe 2 O 4 calcined at 1073 K. Both the magnitude of the hysteresis loss and the temperature dependence of the loss are influenced by the sintering temperature and composition.

The eluent droplet size defines the number of sampling compartments in a continuously operated annular electrochromatograph and therefore influences separation efficiency. In this work, an assembly of two capillaries, a feeding capillary on the top and a receiving capillary placed under it, has been investigated to control droplet size. The receiving capillary prevents the liquid droplet formation beyond a critical size, which reduces the volume of sampling compartment as compared with the case of the electrolyte flow driven solely by gravity. With a receiving capillary, the electrolyte droplet size was reduced from 1.5 to 0.46¿mm. Further decrease of droplet size was not possible due to a so-called droplet jump upwards effect which has been observed on a hydrophilic glass surface with water. A typical electrolyte used in CAEC has high methanol content. In an attempt to improve the methanol-repellent properties of the glass surface, two approaches have been implemented: (i) self-assembled chemisorbed monolayers of an alkylsiloxane and (ii) fabrication of a nano-pin film. The methanol-repellent surface of the feeding capillary suppressed the droplet jump upwards effect. The surface remained methanol repellent in different solutions with lower polarity than that of water.

New routes for the preparation of highly active TiO(2)-supported Cu and CuZn catalysts have been developed for C-O coupling reactions. Slurries of a titania precursor were dip-coated onto glass beads to obtain either structured mesoporous or non-porous titania thin films. The Cu and CuZn nanoparticles, synthesized using a reduction by solvent method, were deposited onto calcined films to obtain a Cu loading of 2 wt%. The catalysts were characterized by inductively coupled plasma (ICP) spectroscopy, temperature-programmed oxidation/reduction (TPO/TPR) techniques, (63)Cu nuclear magnetic resonance (NMR) spectroscopy, X-ray diffraction (XRD), scanning and transmission electron microscopy (S/TEM-EDX) and X-ray photo-electron spectroscopy (XPS). The activity and stability of the catalysts obtained have been studied in the C-O Ullmann coupling of 4-chloropyridine and potassium phenolate. The titania-supported nanoparticles retained catalyst activity for up to 12 h. However, catalyst deactivation was observed for longer operation times due to oxidation of the Cu nanoparticles. The oxidation rate could be significantly reduced over the CuZn/TiO(2) catalytic films due to the presence of Zn. The 4-phenoxypyridine yield was 64% on the Cu/nonporous TiO(2) at 120 °C. The highest product yield of 84% was obtained on the Cu/mesoporous TiO(2) at 140 °C, corresponding to an initial reaction rate of 104 mmol g(cat) (-1) s(-1). The activation energy on the Cu/mesoporous TiO(2) catalyst was found to be (144±5) kJ mol(-1), which is close to the value obtained for the reaction over unsupported CuZn nanoparticles (123±3 kJ mol(-1)) and almost twice the value observed over the catalysts deposited onto the non-porous TiO(2) support (75±2 kJ mol(-1)).

Composite magnetic catalysts containing different amounts of sulfated titania (33&ndash, 50 wt %) have been prepared by means of high energy ball-milling between TiO2 and NiFe2O4. The catalysts have been characterized with N2 adsorption/desorption isotherms, XRD, temperature programmed oxidation (TPO) and vibrating sample magnetometer (VSM). The catalytic activity was measured in the reaction of aniline and 4-phenylbutyric acid in the continuous mode under conventional and inductive heating. The effect of catalyst loading in the reactor on reaction and deactivation has been studied, indicating the catalyst containing 50 wt % titania gave the highest reaction rate and least deactivation. The operation in a flow reactor under inductive heating increased the amide yield by 25% as compared to conventional heating. The initial reaction rate decreased by 30% after a period of 15 h on stream. The catalyst activity was fully restored after a treatment with an air flow at 400 &deg, C.

As an emerging technology that features the integration of microfluidics and non-equilibrium plasmas, microfluidic plasmas not only allow the precise and effective matter and heat transport via the microfluidic system, but also provide an extremely reactive medium full of high energy plasma-generated species. Therefore, they could open new pathways for chemical synthesis or chemical engineering processes that are hardly achievable by conventional methods. In this review, three main microfluidic plasma configurations are reviewed, including plasmas confined within microchannels, plasma jets beyond microchannels and microfluidic plasma arrays. The state-of-the-art diagnostic techniques for characterizing the microfluidic plasma are also examined. A broad range of applications of microfluidic plasmas of particular interest to chemistry and chemical engineering, such as nanomaterials fabrication, surface modification, chemical synthesis, environmental application, and micro total analysis systems, are discussed. The research gaps, bottlenecks and future perspectives of this novel technology are presented.