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Control strategies designed for step signals fail when applied for ramp tracking and ramp disturbance rejection. Hence, this work presents a novel dual-loop control technique for ramp tracking and ramp disturbance rejection in unstable systems. To begin with, first the unstable process is stabilized using a proportional-derivative (PD) compensator (in the internal loop). This PD compensator was created utilising the direct synthesis approach. Using the loop shaping approach, a proportional-integral-derivative controller (in the outer-loop) is then developed to integrate stabilised plant dynamics. Simulations are done using standard unstable CSTR (Continuous Stirred Tank Reactor) plant models by applying step/ramp reference signals and disturbances. The proposed control strategy shows a satisfactory servo and regulatory response than the existing designs while dealing with step and ramp types of signals. Lastly, a performance summary is also presented on different errors. [ABSTRACT FROM AUTHOR]

Although various iron-based magnetic materials have been extensively studied in biomedical field for many years, iron boride compounds with interesting chemical and magnetic properties are relatively less explored, and their potential applications are not as widely known. In this study, the synthesis, coating, surface modification, and cytotoxicity tests of the Fe–Zn–B system were presented. Iron boride-based nanoparticles (NPs) containing elemental zinc (Zn) were developed by using a direct chemical synthesis of FeCl 3 , ZnCl 2 and NaBH 4 , and investigated for potential use in biomedical applications. Powders having the phases of pure FeB with small amount of elemental Zn were obtained with a uniform morphology and an average particle size of 68 nm. The NPs were then coated with oleic acid (OA) and surface modified with sodium tricitrate, to increase their stability and biocompatibility, and well-dispersed NPs were obtained with sizes below 30 nm. TEM investigations revealed the presence of hybrid clusters with nanoparticle – OA structures, indicating that FeB nanoparticles were stabilized by being embedded in OA clusters, forming both agglomerated sub-micron and free nano-sized structures. Obtained NPs showed ferromagnetic property, with a saturation magnetization of 25.9 emu/g and a low coercivity of 90 Oe. As a result of testing different types of healthy and cancer cell lines with NPs, Zn-doped-FeB@OA NPs exhibited a high biocompatibility. Results suggested that highly biocompatible and magnetic OA-coated Zn-doped FeB particles can be potential candidates for biomedical applications such as medical imaging or drug delivery systems. [ABSTRACT FROM AUTHOR]

This paper introduces a new analytical technique using a direct synthesis strategy to develop centralised proportional–integral (PI) controllers for multivariable processes. The current method design controller is focused on attaining the desired closed-loop response for multi input multi output (MIMO) processes that involve multiple time delays. The conventional multivariable PI controller is obtained by approximating the ideal multivariable controller by the Maclaurin series expansion. This is accomplished by choosing the desired closed-loop response order as the system order plus two. Subsequent analysis investigates the proposed method's efficacy in designing multivariable PI controllers. Servo and regulatory problems studies were conducted to find the effectiveness of the proposed method and compared it with other methods recently reported in the literature, as well as assessment of performance indices like integral absolute error (IAE) and integral square error (ISE). The proposed controller's robustness is assessed by plotting the inverse maximum singular value against frequency, both input and output multiplicative uncertainties. [ABSTRACT FROM AUTHOR]

Colloidal cesium lead halide (CsPbX3, X = Cl, Br, I) perovskite nanocrystals (NCs) hold promises in photovoltaic and optoelectronic applications. However, their poor long‐term stability results in degradation of optical properties under ambient conditions. Various methods have been explored to address these issues. In this study, we demonstrate that following 3‐precursor hot‐injection method employing ethylenediammonium dihalide (EDAX2) as an additional ligand/halide source one can obtain phase‐pure, monodispersed, stable, and highly luminescent CsPbX3 NCs. Our violet‐emitting CsPbCl3, blue‐emitting CsPbClBr2, Green‐emitting CsPbBr3, yellow‐emitting CsPbBr2I, and red‐emitting CsPbI3 NCs show PLQYs of 53%, 97%, 96%, 93%, and 95%, respectively. Moreover, the CsPbI3 NCs, which are known for their phase instability, exhibit stability for up to two months under ambient conditions. The enhanced stability and photoluminescence are attributed to strong binding of the bidentate ligand (EDA2+) to the surface of the NCs and effective removal of the halide‐deficiency trap states by X−. [ABSTRACT FROM AUTHOR]

Summary: The synthesis of octenyl succinic anhydride‐modified starch was achieved through a fluidised bed activated by jet milling with graded revolution rates of 1200, 1800, 2400, 3000, and 3600 rpm. This study investigated the changes in the structural, physicochemical, and application properties of modified starch after jet milling. The results showed that modified starch can be synthesised using a one‐step jet milling process. The degree of substitution increased with a decrease in the starch particle size, resulting in a rough granule morphology. Structural analysis revealed that crystalline areas were destroyed in the modified starches. In the Fourier‐infrared spectrum, typical peaks appeared at 1724 and 1573 cm−1 upon introduction of the octenyl succinic anhydride group, whereas a new sodium peak appeared in the XPS spectrogram. The 1H‐NMR spectrum indicated that the esterification reaction mainly occurred on OH2 groups. The emulsification properties of the modified starch were significantly enhanced and increased with the crushing strength. The octenyl succinic anhydride‐modified starch has potential as a wall material for microcapsules, with good embedding rate and thermal stability. This novel synthesis method represents an innovative method for the synthesis of OSA‐starches. [ABSTRACT FROM AUTHOR]

Compounds containing a 2‐deoxy β‐glycoside linkage play important roles in carbohydrate chemistry, serving as potential therapies with significant biological properties. From the viewpoint of synthesis, many strategies developed in recent years targeted the stereoselective construction of 2‐deoxy glycosides. This review aims to summarise recent advances in the synthetic routes toward 2‐deoxy β‐glycosides developed over the last decade. Where associated, practical applications of these strategies in the total synthesis of natural products are highlighted. [ABSTRACT FROM AUTHOR]

To investigate highly performance catalysts for the direct synthesis of dimethyl carbonate (DMC) from carbon dioxide (CO2) and methanol, a Co0.02/Ce0.7Zr0.3O2 ternary metal solid solution nanoparticle catalyst was synthesized, demonstrating superior performance with a DMC yield of 3.86 mmol g−1 and selectivity of 100 % at 7 MPa and 140 °C. A series of characterizations further validated the successful incorporation of cobalt and zirconium into the crystal lattice of CeO2, resulting in an increased number of acid-base sites on its surface and a rise in oxygen vacancy content from 10.1 % to 28.7 %. The density functional theory (DFT) calculation results further corroborated the experimental findings, indicating that the doping of cobalt and zirconium ions significantly reduced the formation energy of oxygen vacancies on the catalyst surface from 2.53 to −1.38 eV, while concurrently decreasing the adsorption energy of CO2 from −0.33 to −1.74 eV. Additionally, charge calculation results revealed that oxygen vacancies functioned as Lewis acid sites, whereas lattice oxygen atoms served as Lewis base sites, facilitating the cooperative activation of CO2. The results may provide a new approach for designing and improving CeO2-based catalysts for CO2 activation.

The direct synthesis of dimethyl carbonate (DMC) from carbon dioxide (CO2) and methanol (MeOH) is a DMC preparation route that meets the requirements of green chemistry and can realize the resource utilization of CO2. Cerium oxide (CeO2) based catalysts are widely used in this reaction. The current researches focus on the effects of morphology regulation and heteroatom doping on the catalytic performance of the catalysts. The rod-shaped CeO2 precursor was prepared by hydrothermal synthesis method, and then the corresponding catalysts were obtained by calcining the precursor in different atmospheres (H2, N2, air and O2, respectively). Then the catalysts were applied to the direct synthesis of DMC from CO2 and MeOH with 2-cyanopyridine (2-cp) as dehydrating agent (adding 0.10 mol MeOH, 0.05 mol 2-cp and 0.32 g catalyst, reaction at the conditions of 120 °C and 5 MPa for 2 h). The effects of calcination atmospheres on the catalytic performance of catalysts were studied. The crystal structures, texture properties and morphologies of the catalysts were characterized by XRD, N2 absorption/desorption, SEM, etc. The results show that the four catalysts show no significant differences in structural properties and morphologies, and the valence of Ce on the catalysts surface is closely related to acid-base sites. The abundant defect sites on the catalysts surface enable them to have large specific surface areas and average pore sizes (specific surface area and average pore size of CeO2-air are 65.44 m²/g and 30.06 nm, respectively). The main exposed CeO2(111) crystal surface of the catalysts can promote the formation of DMC. Compared with the other three catalysts, CeO2-air exhibits the best catalytic performance due to its highest concentration of medium and strong acid-base sites and total acid-base sites, as well as the enhancement of weak acid acidity. The DMC yield and DMC selectivity of CeO2-air are 83.2% and 99.3%, respectively. [ABSTRACT FROM AUTHOR]

Understanding the performance differences of palladium–tin (Pd–Sn) nanocrystal phases lays the foundation to fine-tune their catalytic activity in direct hydrogen peroxide (H2O2) synthesis (DHS). This study prepared hexagonal Pd3Sn2, orthorhombic Pd2Sn, and cubic Pd3Sn nanoparticles by solvothermal synthesis for DHS. The results reveal that hexagonal Pd3Sn2/TiO2 exhibits a superior DHS performance, as well as lower H2O2 degradation and hydrogenation, compared to orthorhombic Pd2Sn/TiO2, cubic Pd3Sn/TiO2, and Pd/TiO2. Detailed characterization and theoretical calculations indicate that hexagonal Pd3Sn2/TiO2 with higher PdO and SnOx contents presents lower adsorption and desorption capacities of hydrogen and oxygen than other catalysts. H2O2 can be rapidly generated once H2 and O2 are adsorbed on hexagonal Pd3Sn2/TiO2. High productivity and selectivity of H2O2 are achieved due to the lower energy barrier for the initial hydrogenation of *O2 to *OOH and the stability of H2O2 on hexagonal Pd3Sn2/TiO2 with the (102) facet. This study offers in-depth insights into Pd-based bimetallic alloys for DHS from the perspective of crystalline phase engineering. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) vertical van der Waals heterostructures (vdWHs) show great potential across various applications. However, synthesizing large-scale structures poses challenges owing to the intricate growth parameters, forming unexpected hybrid film structures. Thus, precision in synthesis and thorough structural analysis are essential aspects. In this study, we successfully synthesized large-scale structured 2D transition metal dichalcogenides (TMDs) via chemical vapor deposition using metal oxide (WO3 and MoO3) thin films and a diluted H2S precursor, individual MoS2, WS2 films and various MoS2/WS2 hybrid films (Type I: MoxW1−xS2 alloy; Type II: MoS2/WS2 vdWH; Type III: MoS2 dots/WS2). Structural analyses, including optical microscopy, Raman spectroscopy, transmission electron microscopy (TEM) with energy-dispersive X-ray spectroscopy, and cross-sectional imaging revealed that the A1g and E2g modes of WS2 and MoS2 were sensitive to structural variations, enabling hybrid structure differentiation. Type II showed minimal changes in the MoS2′s A1g mode, while Types I and III exhibited a ~2.8 cm−1 blue shift. Furthermore, the A1g mode of WS2 in Type I displayed a 1.4 cm−1 red shift. These variations agreed with the TEM-observed microstructural features, demonstrating strain effects on the MoS2–WS2 interfaces. Our study provides insights into the structural features of diverse hybrid TMD materials, facilitating their differentiation through Raman spectroscopy. [ABSTRACT FROM AUTHOR]

Unstable processes are challenging to control because they have one or more positive poles that produce unrestrained dynamic activity. Controlling such unstable plants becomes more challenging with the occurrence of the delay. This article presents a novel direct synthesis based sliding mode controller design for unstable second order plus dead-time processes. A sliding surface with three parameters has been considered. The continuous control law, which is responsible for maintaining the system mode to the desired sliding surface mode, has been obtained using the direct synthesis approach. The discontinuous control law parameters have been obtained using the differential evolution optimization technique. A desired reference model is considered for the direct synthesis method, and an objective function is constituted in terms of performance measure (integral absolute error) and control effort measure (total variation of controller output) for the optimization approach. Illustrative examples show the superiority of the proposed controller design method over recently reported literature, especially in terms of load rejection. The proposed controller approach is further extended to control the temperature of a nonlinear chemical reactor. Furthermore, the robustness of the proposed controller is also investigated for plant parametric uncertainty. [ABSTRACT FROM AUTHOR]

Laser powder bed fusion (LPBF) additive manufacturing, as a novel technique provides broad benefits in thermoelectric materials synthesis, such as enhanced printing speed, reduced waste materials, and customized dimension design. The high energy density of laser could potentially balance the synthesis rate and thermoelectric figure-of-merit zT , but the correlations between laser energy and material performance are still vague. Herein, Bi 0.5 Sb 1.5 Te 3 bulks are directly synthesized by LPBF with a recorded synthesis rate of 254 g h−1. The maximum zT , without any post-processing, reaches 1.1 at 75 °C. Induced nanoscale pores by high laser energy printing, obtain a comparable diameter to phonon mean free path, leading to reduced lattice thermal conductivity and enhanced TE performance. We found that input laser energy critically affected thermoelectric performance and concluded the correlation between volumetric energy density E V and power factor PF , PF = 9.05 E V 2 – 30.01 E V + 48.84. It potentially predicts thermoelectric performance with inputted laser energy density. [ABSTRACT FROM AUTHOR]

The intrinsic lack of processability in the conventional nano/microcrystalline powder form of metal‐organic frameworks (MOFs) greatly limits their application in various fields. Synthesis of MOFs with certain flowability make them promising for multitudinous applications. The direct synthesis strategy represents one of the simplest and efficient method for synthesizing solution processable MOF sols/suspensions, compared with other approaches, for instance, the post‐synthesis surface modification, the direct dispersion of MOFs in hindered ionic liquids, as well as the calcination method toward a few MOFs with melting behavior. This article reviews the recent direct synthesis strategies of solution processable MOF sols and their typical applications in different fields. The direct synthesis strategies of MOF sols can be classified into two categories: particle size reduction strategy, and selective coordination strategy. The synthesis mechanism of different strategies and the factors affecting the formation of sols are summarized. The application of solution processable MOF sols in different fields are introduced, showing great application potentials. Furthermore, the challenges faced by the direct synthesis of MOF sols and the main methods to deal with the challenges are emphasized, and the future development trend is prospected. [ABSTRACT FROM AUTHOR]

Direct synthesis of Pyridine-2,6-dicarboxylic a-+cid bis-(3-hydroxy phenyl)]amide, (Pydca), chelating ligand was applied for Th(IV) extraction from Abu Rusheid Ore Sample, South Eastern Desert, Egypt, between latitudes 24° 37ʹ 16ʹʹ N and longitudes 34° 46 ʹ 35 ʹʹ E and far from the Red Sea coast by about 42 km west, using poly phosphoric acid catalyst (PPA). The synthesis of new amide via direct condensation of organic acid and aromatic amine was performed in DMF at 100°C. The immediate condensation reaction led to construct the carboxamide derivative in one easy step dismantling the hard activation, halogenation, step resulting in a good yield production. This cross-coupling reaction appears simple, convenient and has a wide scope of activities. This protocol could be extended to industrial large-scale production processes. Experimental measurements have been optimised such as diluent type, pH, contact time, initial Th(IV) concentration, temperature, pydca conc., co-existing ions and stripping agents. It was found that a maximum value of Th(IV) retention (0.86 × 10−3 mol/L) is observed with 0.015 mol/L pydca/CCl4 chelating ligand at room temperature. From kinetic aspects, it was found that Th(IV) extraction follows the pseudo-first order kinetic model. The thermodynamic parameters, ΔS, ΔH and ΔG were also evaluated indicating an endothermic and spontaneous extraction process with increasing the randomness of the extraction system. Th(IV) can be completely back extracted from the loaded pydca chelating ligand using 0.5 M HNO3, 1 M H2SO4 and 1 M HCl. Finally, the optimised factors have been applied for Th(IV) recovery from Abu Rusheid Ore Sample, South Eastern Desert, Egypt, producing a thorium oxide concentrate with Th(IV) content of 81.43% with a purity of 92.67%. [ABSTRACT FROM AUTHOR]

This work is dedicated to the study of the effect of the synthesis conditions (drying and calcination) of sulfated zirconia on the final catalytic behavior of bifunctional composite catalysts prepared by the physical mixing of the sulfated zirconia (methanol dehydration catalyst) with Cu/ZnO/Al2O3 (CZA; methanol synthesis catalyst). The main objective was to optimize the CZA-ZrO2/SO42− composite catalyst for its use in the direct production of dimethyl ether (DME) from syngas. Sulfated zirconia aerogel (AZS) and xerogel (XZS) were prepared using the sol–gel method using different solvent evacuation conditions and calcination temperatures, while the Cu-ZnO(Al) catalyst was synthesized using the coprecipitation procedure. The effectivity of CZA-ZrO2/SO42− composite catalysts for the direct production of dimethyl ether (DME) from syngas was evaluated in a flow reactor at 250 °C and 30 bar total pressure. The characterization of the sulfated zirconia aerogels and xerogels using different techniques showed that the mesoporous aerogel (AZS0.5300) exhibited the best textural and acidic properties due to the gel drying under supercritical conditions and calcination at 300 °C. As a result, the composite catalyst CZA-AZS0.5300 exhibited seven times higher DME production than its xerogel-containing counterpart (364 vs. 52 μmolDME·min−1·gcat−1). This was attributed to its well-matched metal surface, mesoporous structure, optimal crystallite size and, most importantly, its higher acidity. [ABSTRACT FROM AUTHOR]

Biosensors based on graphene field-effect transistors (G-FET) for detecting COVID-19 spike S protein and its receptor ACE2 were reported. The graphene, directly synthesized on SiO2/Si substrate by microwave plasma-enhanced chemical vapor deposition (MW-PECVD), was used for FET biosensor fabrication. The commercial graphene, CVD-grown on a copper substrate and subsequently transferred onto a glass substrate, was applied for comparison purposes. The graphene structure and surface morphology were studied by Raman scattering spectroscopy and atomic force microscope. Graphene surfaces were functionalized by an aromatic molecule PBASE (1-pyrenebutanoic acid succinimidyl ester), and subsequent immobilization of the receptor angiotensin-converting enzyme 2 (ACE2) was performed. A microfluidic system was developed, and transfer curves of liquid-gated FET were measured after each graphene surface modification procedure to investigate ACE2 immobilization by varying its concentration and subsequent spike S protein detection. The directly synthesized graphene FET sensitivity to the receptor ACE2, evaluated in terms of the Dirac voltage shift, exceeded the sensitivity of the transferred commercial graphene-based FET. The concentration of the spike S protein was detected in the range of 10 ag/mL up to 10 μg/mL by using a developed microfluidic system and measuring the transfer characteristics of the liquid-gated G-FETs. It was found that the shift of the Dirac voltage depends on the spike S concentration and was 27 mV with saturation at 10 pg/mL for directly synthesized G-FET biosensor, while for transferred G-FET, the maximal shift of 70 mV was obtained at 10 μg/mL with a tendency of saturation at 10 ng/mL. The detection limit as low as 10 ag/mL was achieved for both G-FETs. The sensitivity of the biosensors at spike S concentration of 10 pg/mL measured as relative current change at a constant gate voltage corresponding to the highest transconductance of the G-FETs was found at 5.6% and 8.8% for directly synthesized and transferred graphene biosensors, respectively. Thus, MW-PECVD-synthesized graphene-based biosensor demonstrating high sensitivity and low detection limit has excellent potential for applications in COVID-19 diagnostics. [ABSTRACT FROM AUTHOR]

This paper discusses the historical beginnings and the current state of knowledge of the synthesis of organosilicon compounds and chlorine derivatives of silicon. The key importance of these compounds for modern industry, including the semiconductor industry (photovoltaic cells, microprocessors, memory chips and many other electronic elements) is highlighted. Significant environmental threats related to the production of these compounds and the research challenges aimed at their elimination are discussed. The complexity of the catalytic mechanism of direct reaction of silicon with CH3Cl and alcohols is presented in an accessible way. In the last part of the work, the directions of the development of direct synthesis technology in line with the principles of green chemistry are indicated.

Using the direct synthesis method, by oxidative dissolution of copper powder in the presence of CuBr2 and C5H8N2 (3,5-dimethyl-1H-pyrazole), three different types of crystals were formed, isolated, and identified. Three new coordination compounds, trinuclear [Cu3(µ3-OH)( µ2-C5H7N2Br)( µ2-Br)3(C5H8N2)5Br]⋅CHCh (where C5H7N2Br - 4-bromo-3,5-dimethylpyrazole) (1) (orthorhombic, Pnma), binuclear [Cu2(µ2-C5H7N2Br)( µ2-Br)( C5H7N2)4Br2]⋅2CHCl3 (2) (monoclinic, C2/c) and mononuclear [CuBr2( C5H7N2)3] (3) (triclinic, PI), have been obtained. According to the single-crystal X-ray diffraction analysis, the complex 1 is a trinuclear six-membered cycle, where copper atoms are connected by three types of bridges: µ2-bromide ions, µ2-4-bromo-3,5-dimethylpyrazole molecule, and µ3-hydroxo group. The binuclear complex 2 is formed due to a connection between two copper atoms by a bidentate-bridging bromide ion and a bridged 4-brominated 3,5-dimethylpyrazole molecule. Coordination compound 3 is a mono-nuclear trigonal-bipyramidal copper(II) complex. During the reaction, some part of 3,5-dimethylpyrazole molecules was brominated in the 4th position of the pyrazole ring. The Hirshfeld surface analysis reveals that the inter- molecular H⋯H contacts have the highest contribution to the crystal packing of all compounds: 66.9 % for 1, 54.4 % for 2, and 66.5 % for 3. [ABSTRACT FROM AUTHOR]

ZrO2 and catalysts were prepared by a co-precipitate method and coupled with a HZSM-5 zeolite catalyst through a mechanical mixing method; these were applied to the direct synthesis of aromatic hydrocarbons from syngas through an oxygen-containing intermediate route. The physical and chemical properties of the catalysts were characterized by XRD, H2-TPR, CO2-TPD, and SEM methods. The comparative catalytic effects of ZrO2 and MgZrOx catalysts were discussed under different reaction conditions. The reaction results showed that the addition of Mg to a ZrO2 catalyst reduced the selectivity of CO2 by inhibiting the water–gas conversion reaction, and increased the selectivity of aromatics and the proportion of BTX in aromatic products. [ABSTRACT FROM AUTHOR]

In this work, a PID controller along with a noise filter is designed using direct synthesis method for second order stable and unstable processes with time delay. Proposed method involves a single design parameter λ whose value need to be adjusted such that a desired balance between performance and robustness of the system is achieved. Guidelines to select suitable values of λ based on the maximum sensitivity values are provided. Various computer simulations are performed in presence of measurement noise on stable, unstable, integrating and double integrating dynamic systems to illustrate the advantages of suggested control method over some contemporary techniques. Performance measures (integral absolute error and integral squared error) and robustness measures such as maximum sensitivity (Ms), complimentary sensitivity (Mt) are calculated for the quantitative performance evaluation of the proposed tuning strategy. The suggested tuning algorithm is simple and it yields improved closed loop response compared to some reported methods, satisfactory robustness and smooth control action in presence of noise. [ABSTRACT FROM AUTHOR]

Methanol steam reforming (MSR) is a promising process for in-situ hydrogen production in vehicles. However, designing monolithic catalysts with high activity and selectivity as well as low pressure drop remains a challenge. In this work, CuO–ZnO–CeO 2 catalysts were prepared directly on Al 2 O 3 /cordierite monolith through a sol-gel combustion method, and the effects of different combustion temperatures on the physicochemical properties and catalytic performance of the catalysts were investigated. It is demonstrated that the catalyst (CZC-400) prepared by combustion temperature at 400 °C is uniformly distributed on the Al 2 O 3 /cordierite monolith with smaller average catalyst particle size (4.2 nm) and higher specific surface area (23.7 m2 g−1). In the MSR, methanol conversion of CZC-400 reaches 100% at 260 °C without by-product CO. Furthermore, no significant change in the catalytic activity is observed during 32 h of the reaction. These results indicate that CZC-400 has the excellent catalytic activity and stability in the MSR. [ABSTRACT FROM AUTHOR]

This paper discusses the historical beginnings and the current state of knowledge of the synthesis of organosilicon compounds and chlorine derivatives of silicon. The key importance of these compounds for modern industry, including the semiconductor industry (photovoltaic cells, microprocessors, memory chips and many other electronic elements) is highlighted. Significant environmental threats related to the production of these compounds and the research challenges aimed at their elimination are discussed. The complexity of the catalytic mechanism of direct reaction of silicon with CH3Cl and alcohols is presented in an accessible way. In the last part of the work, the directions of the development of direct synthesis technology in line with the principles of green chemistry are indicated. [ABSTRACT FROM AUTHOR]

Industrial processes often involve a long time delay, which adversely affects the stability of closed-loop control systems. The traditional Smith Predictor (SP) is a model-based controller used in processes with large time delays. The variation of system parameters and load disturbance situations are disadvantages of the traditional SP, and researchers have, therefore, proposed modified SP structures. In this paper, a design method based on the direct synthesis approach on a modified SP structure is discussed. In the design, an I-PD controller structure is used on the set-point tracking side of the SP, and a cascading PD lead–lag controller is used on the disturbance rejection side. In contrast with other studies in the literature, the use of simpler controllers enables the mathematical expressions that arise in the direct synthesis method to be significantly reduced. The proposed method is examined under the disturbance input effects for normal and parameter-changing conditions on system models with unstable second-order plus time-delay processes. The first plant model has two unstable poles, the second has one stable and one unstable pole, and the third has one unstable and one zero pole. When the results obtained using the proposed method were compared with other methods, significant improvements were achieved in terms of set-point tracking, disturbance rejection, and robustness conditions. [ABSTRACT FROM AUTHOR]

In this study, high-quality tin diselenide (SnSe 2) thin films were successfully synthesized using an optimized atmospheric pressure chemical vapor deposition (APCVD) technique. Precise control over key growth parameters, such as substrate temperature and deposition time, enabled the realization of films exhibiting exceptional crystallographic and optical properties. Notably, the growth temperature was found to significantly influence the SnSe 2 film morphology. Under the optimal conditions (250 °C growth temperature and 90 min of deposition), the films exhibited a strong (001) crystal orientation, 24.6 % transmittance, an optical bandgap of 1.55 eV, and an optical thickness of approximately 386.19 nm. Additionally, the films demonstrated N-type semiconductor behavior, making them highly suitable for use in electronic and optoelectronic applications. This study provides valuable insights for the large-scale production of high-performance SnSe 2 thin films suitable for electronic and optoelectronic applications. [Display omitted] • APCVD enables direct synthesis of SnSe 2 films, offering a novel approach to fabricating thin films of layered metal sulfides. • Reveals growth temperature-dependent effects on morphology, providing insights into controlling SnSe 2 film structure. • The SnSe 2 films exhibit excellent absorption under the visible. [ABSTRACT FROM AUTHOR]

The title coordination polymer, [Cu(SO4)(C5H8N2)4]n, was synthesized using a one-pot reaction of copper powder, anhydrous copper(II) sulfate and 3,5-dimethyl-1H-pyrazole (Hdmpz) in acetonitrile under ambient conditions. The asymmetric unit can be described as a chain consisting of four [Cu(SO4)(Hdmpz)4] formula units that are connected to each other by a μ2-sulfato-bridged ligand. The octahedral coordination geometry (O2N4) of all copper atoms is realized by coordination of four pyrazole ligands and two sulfate ligands. Four pyridine-like N atoms of the pyrazole ligands occupy the equatorial positions, while two oxygen atoms of two sulfate ligands are in axial positions. As a result of the sulfate ligand rotation, there is a pairwise alternation of terminal O atoms (which are not involved in coordination to the copper atom) of the SO4 tetrahedra. The Cu...Cu distances within one asymmetric unit are in the range 7.0842 (12)–7.1554 (12) Å. The crystal structure is built up from polymeric chains packed in a parallel manner along the b-axis direction. Hirshfeld surface analysis suggests that the most important contributions to the surface contacts are from H...H (74.7%), H...O/O...H (14.8%) and H...C/C...H (8.2%) interactions.

Complexes [Сu(NCS)2L3], [Сu(NO3)2L4] and [Cu(NCS)2L4]·L have been prepared by direct synthesis involving the interaction of metallic copper, ammonium salts NH4X (Х = NCS, NO3) and 1-tert-butyl-1H-1,2,4-triazole (L). Their composition and structure were determined by elemental analysis, single crystal X-ray analysis, and IR spectroscopy (range of 4000–500 cm–1). All the complexes showed mononuclear structure. In them triazole acts as a monodentate ligand, being coordinated by the N4 atom of the heterocycle. The NCS– and NO–3 anions display monodentate N- and O-coordination, accordingly. In [Сu(NCS)2L3], copper(II) cation has square-pyramidal environment of nitrogen atoms of two ligands L and two thiocyanate anions in the basal sites, and one nitrogen atom of ligand L in the apical position. In complexes [Сu(NO3)2L4] and [Cu(NCS)2L4]·L, copper(II) cations are octahedrally surrounded by nitrogen atoms of ligand L in the equatorial sites and by O or N atoms of corresponding anions in the axial positions.

Metal-organic frameworks (MOFs), constructed by inorganic secondary building units with organic linkers via reticular chemistry, inherently suffer from poor solution processability due to their insoluble nature, resulting from their extensive crystalline networks and structural rigidity. The ubiquitous occurrence of precipitation and agglomeration of MOFs upon formation poses a significant obstacle to the scale-up production of MOF-based monolith, aerogels, membranes, and electronic devices, thus restricting their practical applications in various scenarios. To address the previously mentioned challenge, significant strides have been achieved over the past decade in the development of various strategies aimed at preparing solution-processable MOF systems. In this review, the latest advance in the synthetic strategies for the construction of solution-processable MOFs, including direct dispersion in ionic liquids, surface modification, controllable calcination, and bottom-up synthesis, is comprehensively summarized. The respective advantages and disadvantages of each method are discussed. Additionally, the intriguing applications of solution-processable MOF systems in the fields of liquid adsorbent, molecular capture, sensing, and separation are systematically discussed. Finally, the challenges and opportunities about the continued advancement of solution-processable MOFs and their potential applications are outlooked., (© 2024 Wiley‐VCH GmbH.)

The title compound, [Cu2Cl4(C5H10N2O2)2(CH3CN)2] or [Cu2(μ2-Cl)2(CH3—Pz-COOCH2CH3)2Cl2(CH3CN)2], was synthesized using a one-pot reaction of copper powder, copper(II) chloride dihydrate and ethyl 5-methyl-1H-pyrazole-3-carboxylate (CH3—Pz-COOCH2CH3) in acetonitrile under ambient conditions. This complex consists of discrete binuclear molecules with a {Cu2(μ2-Cl)2} core, in which the Cu...Cu distance is 3.8002 (7) Å. The pyrazole-based ligands are bidentate coordinated, leading to the formation of two five-membered chelate rings. The coordination geometry of both copper atoms (ON2Cl3) can be described as distorted octahedral on account of the acetonitrile coordination. A Hirshfeld surface analysis suggests that the most important contributions to the surface contacts are from H...H (40%), H...Cl/Cl...H (24.3%), H...O/O...H (11.8%), H...C/C...H (9.2%) and H...N/N...H (8.3%) interactions.

Acetonitrile is used as an effective, non-corrosive selectivity enhancer for the direct synthesis of hydrogen peroxide (HP). Palladium catalysts supported by activated carbon or poly-divinylbenzene are poisoned by acetonitrile, which makes them very little productive. Conversely the catalysts supported by strongly acidic ion-exchange resin are much more selective and productive in the presence of acetonitrile, and for relatively long time. TEM shows that the size of their metal nanoparticles can be decreased by a reconstruction process, possibly sustained by leached palladium(II) species. HP decomposition experiments show that acetonitrile inhibits the OO bonds splitting.

Several characterization techniques were employed to elucidate the Pt species present in the structure of Pt-NaA catalysts. Three types of Pt particles were identified: nanoparticles located at the surface of the crystals (with a higher size and flattened form), 1–2 nm particles inside the structure, and sub-nanometric particles, lower than 1 nm, confined in the pores. The low PtPt coordination number (EXAFS) is compatible with both flattened dihedral-like morphology, as well as the presence of sub-nanometric particles. The Pt0.6_NaA catalyst exhibited higher activity (in the WGS) than the other catalysts, which could be related to the presence of small particles.

This work is the third and final part of a series of reviews devoted to the direct synthesis of organotin compounds. This part of the series considers the conditions of and results from the reaction between metallic tin and carbofunctional organohalides. The efficiency of catalysts and the prospects for direct synthesis in the production of carbofunctional organotin compounds are analyzed. [ABSTRACT FROM AUTHOR]

HZSM-5 zeolites as catalysts are conventionally synthesized through three steps: (1) preparation of Na type zeolites; (2) ion exchange into NH4 type; (3) calcination. In this work, binder-free HZSM-5 zeolites with SiO2/Al2O3 ratios of 50–170 were directly synthesized in the shaped form. The acid properties and pore structures of the HZSM-5 samples were appreciably affected by the SiO2/Al2O3 ratio. In addition, these HZSM-5 samples had well preserved micropore structure, and even exhibited superior properties to the conventional one in methanol to hydrocarbon reaction with about 13% higher yield of C5+ hydrocarbons and 63% higher aromatic selectivity. The improved catalytic performance might be attributed to the shortened b-axis, more acid sites, stronger acidity and higher Bronsted to Lewis acid ratios. More importantly, this synthesis method not only greatly simplifies the synthesis process of shaped HZSM-5 zeolites, but also reduces pollution and production cost. [ABSTRACT FROM AUTHOR]

Post-synthesis and direct synthesis methods were employed to prepare hierarchical β zeolite. In the former, commercial microporous β was treated by NaOH to introduce mesoporosity. In the latter, hierarchical β zeolites were hydrothermally synthesized using a cationic polymer as a bifunctional template, and the influence of the surface area of silica resources on the samples was investigated. The results showed that a silica source with a small surface area leads to the formation of higher mesopore volume and larger pore size. Three kinds of Zr-β zeolite (microporous Zr-β, hierarchical Zr-β through post-synthesis and, hierarchical Zr-β through direct synthesis) were prepared by dealumination-metallization process and were used for the conversion of ethanol-acetaldehyde to 1,3-butadiene (BD). The catalysts were evaluated in a fixed bed reactor under the following conditions: temperature, 325 °C; pressure, 1 atm; WHSV, 1.04 h−1; time on stream, 6 h. Compared with microporous Zr-β, hierarchical zeolite catalysts can obviously improve the conversion from 34.1 to 57.5% and stability of BD selectivity at 71.4%. And hierarchical catalyst through direct synthesis exhibited the same deactivation behavior with microporous Zr-β catalyst, while introduced mesoporosity by post-synthesis exhibited higher and heavier coke formation due to its higher acid amount. [ABSTRACT FROM AUTHOR]

The structure of the gas distributor was optimized to enhance the reaction rate of direct synthesis of silicone monomers in a fluidized bed. In this work, the opening rate range was selected by the critical pressure drop ratio, and the influences of opening ratio and the holes quantities of distribution plate on the synthesis process were systematically studied by numerical simulation approaches. The fluidization velocity was simplified by Reylows' and Archimedes' criterion numbers. To better predict the gas-solid fluidization characteristics in the bed, the drag model was modified by the critical fluidization velocity. In addition, the distributor performance was investigated from the perspectives of solid phase volume fraction, pressure drop change, bubble behavior and power spectrum analysis, etc. The results show that the distribution plate pressure drop ratio is about 0.11679 at the opening rate of 0.53%, which meets the design criterion of reducing the dissipation while increasing the fluidized quality. A high frequency and a low amplitude arise at the opening rate of 0.53%, indicating the corresponding favorable efficiency of heat and mass transfer. The maximum fluctuation range of the solid phase distribution with Φ=0.53% is only 1.7%, indicating that the inhomogeneity of the solid phase fraction distribution is the lowest, and the fluidization stability is improved by about 30%. Consequently, Φ=0.53% is proposed as the best distributor configuration and enhanced the monomer synthesis efficiency. [ABSTRACT FROM AUTHOR]

• A nest-shaped hollow-encapsulated Pd catalyst named Pd Multi @ONHCS, was successfully synthesized and used for the first time in DSHP at atmospheric pressure. • The special structure of Pd Multi @ONHCS catalyst creates a distinctive catalytic microreactor environment with a spatial mass transfer constraint for DSHP. • Experimental and molecular dynamics simulation both show that the hollow structure of Pd Multi @ONHCS catalyst significantly affects DSHP performance by influencing spatial mass transfer and diffusion resistance within the carbon nanopores. A well-defined structural morphology can significantly construct a special catalytic micro-reaction environment to enhance the catalytic performance of Pd catalyst in the direct synthesis of hydrogen peroxide from hydrogen and oxygen (DSHP). In this study, SiO 2 was used as a rigid template, PdCl 2 as the Pd precursor, and dopamine hydrochloride (DA) as the carbon and nitrogen source to synthesize a nest-shaped hollow-encapsulated Pd catalyst named Pd Multi @ONHCS. This catalyst was successfully constructed via high-temperature pyrolysis of poly dimethyl diallyl ammonium chloride (PDDA), which generated a blasting effect crucial for this formation. Characterization analysis, catalytic performance evaluation experiment, and molecular dynamics simulation were conducted to explore the structure-performance relationship of Pd Multi @ONHCS catalyst in DSHP. Both experimental and simulation results consistently showed that the nest-shaped hollow structure of Pd Multi @ONHCS catalyst created a distinctive catalytic microreactor environment with a spatial mass transfer constraint, which was not only conducive to adsorption and enrichment of H 2 and O 2 at Pd active sites to produce H 2 O 2. In addition, the generated H 2 O 2 can be desorbed from Pd active sites in time and rapidly diffused into the reaction solution, effectively inhibiting the dissociation of species containing O O bonds on the Pd surface, resulting in severe hydrogenation and decomposition side reactions, and improving H 2 O 2 productivity and selectivity. By organically combining carbon support with structural morphology, a nest-shaped hollow-encapsulated Pd catalyst named Pd Multi @ONHCS catalyst was successfully constructed and first used for DSHP from H 2 and O 2 at atmospheric pressure. Pd Multi @ONHCS catalyst with a new structural morphology provided a distinctive catalytic microreactor cavity and constraint effect of spatial mass transfer to enhance the catalytic performance for DSHP, ultimately improving H 2 O 2 productivity and H 2 O 2 selectivity. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • The silicon-modified Al 2 O 3 supported PdAu bimetallic nanoparticles were synthesized. • PdAu/Si 5.6 Al with silica content of 57.2% exhibits the best H 2 consumption TOF and H 2 O 2 formation TOF. • Silica, as Brønsted (B) acid site, has a reverse hydrogen spillover effect. • The adsorption and dissociation of H 2 into atomic H at B acid sites would spill across the support to PdAu nanoparticles reversely. Supported PdAu bimetallic nanoparticles have been developed for the direct synthesis of H 2 O 2 (DSHP). However, to date, the dilute H 2 streams necessary to avoid potential risks of explosion limits the attainable product concentrations of H 2 O 2. Here, a series of silicon-modified Al 2 O 3 (Si x Al) were synthesized for loading PdAu bimetallic nanoparticles. The H 2 consumption turnover frequency (TOF) and H 2 O 2 formation TOF show a volcano trend with the silica content, where PdAu/Si 5.6 Al exhibits the best H 2 consumption TOF and H 2 O 2 formation TOF (11259.3 and 1995.2 h−1). Silica on the surface of Al 2 O 3 is identified as Brønsted (B) acid site. The increase of B acid sites density accelerates the H 2 conversion into H atoms, thereby boosting H 2 O 2 formation process. The adsorption and dissociation of H 2 into atomic H at B acid sites would spill across the support to PdAu nanoparticles reversely. The reversed hydrogen spillover effect induced by B acid site accounts for enhanced H 2 conversion and H 2 O 2 productivity for PdAu/Si x Al. [ABSTRACT FROM AUTHOR]

Carbon dioxide capture is an effective method to mitigate climate change. Highly CO 2 -selective and highly moisture-resistant absorbent is essential for energy-efficient carbon capture by absorption. Herein, a highly CO 2 -selective and high-silica CHA zeolite in a pure lithium form (Li-SSZ-13) was synthesized using a direct synthesis method for the first time. The effects of gel n (SiO 2)/ n (Al 2 O 3) ratio, gel n (SiO 2)/ n (Li 2 O) ratio and synthesis time on the crystallinity, yield, micropore volume and CO 2 loading of the crystals were systematically investigated. The adsorption isotherms of CO 2 and N 2 were measured for directly synthesized Li-SSZ-13, conventional Na-SSZ-13 and ion-exchanged Li-Na-SSZ-13 zeolites. The dynamic breakthrough adsorption properties were measured for Li-SSZ-13 in comparison with Na-SSZ-13 and Li-Na-SSZ-13. The obtained Li-SSZ-13 exhibited a high CO 2 adsorption capacity of 4.48 mmol/g and a high CO 2 /N 2 IAST selectivity of 310 at 100 kPa and 273 K, which were 45.0 % and 441 % higher than Na-SSZ-13 zeolite, 24.8 % and 179 % higher than Li-Na-SSZ-13 zeolite, respectively. It suggests that directly synthesized Li-SSZ-13 zeolite has great potential for efficient CO 2 capture from flue gas. [Display omitted] • Pure lithium form Li-SSZ-13 was prepared by direct synthesis route for the first time. • Li-SSZ-13 zeolite displayed higher CO 2 adsorption capacity and CO 2 /N 2 selectivity than Na-SSZ-13 and Li-exchanged ones. • A high CO 2 /N 2 IAST selectivity of 310 was achieved. • Breakthrough experiments demonstrated that Li-SSZ-13 is a potentially good CO 2 adsorbent. [ABSTRACT FROM AUTHOR]

We have studied the direct synthesis of hydrogen peroxide using a catalytic system consisting of palladium supported on silica bifunctionalized with sulfonic acid groups and bromide in the absence of acid and halide promoters in solution. Catalysts with several bromide substituents were employed in the catalyst synthesis. The prepared samples were characterized by TXRF, XPS, and hydrogen peroxide decomposition. Catalysts characterization indicated the presence of only palladium (II) species in all of the samples, with similar values for surface and bulk of Pd/Br atomic ratio. The catalysts were tested via direct synthesis, and all samples were able to produce hydrogen peroxide at 313 K and 5.0 MPa. The hydrogen peroxide yield and selectivity changed with the Pd/Br ratio. A decrease in the Pd/Br ratio increases the final hydrogen peroxide concentration, and the selectivity for H2O2 reaches a maximum at a Pd/Br ratio around 0.16 and then decreases. However, the maximum hydrogen peroxide concentration and selectivity occur at slightly different Pd/Br ratios, i.e., resp. 0.4 vs. 0.16. [ABSTRACT FROM AUTHOR]

[Display omitted] • A kinetic model was developed for direct synthesis of DME over a hybrid CZA/FER catalyst. • The kinetic parameters were estimated by fitting the experimental data. • Methanol synthesis step might have more control over the overall reaction rate than the dehydration step. • The optimal range of the operating conditions was found by using the developed model. A kinetic model for the direct synthesis of dimethyl ether (DME) from syngas over a hybridized Cu/ZnO/Al 2 O 3 /ferrierite (CZA/FER) catalyst was developed. Kinetic parameters including reaction rate and equilibrium constants were estimated by fitting experimental data for the hybrid catalyst, and these were compared with the reported values for conventional catalysts. High activation energies for the hybrid CZA/FER catalyst showed that the methanol synthesis step may have more control over the rate than the methanol dehydration step. This may be attributed to the core-shell structure of the hybrid catalyst in such a way that the diffusion resistance plausibly plays an important role in the kinetics; this feature was reflected in our estimated kinetic parameters. Using the developed kinetic model, a temperature between 200 and 220 °C was determined for thermal energy efficiency, and a further analysis provided the optimal range of the total pressure and space velocity. [ABSTRACT FROM AUTHOR]

The title coordination polymer, [Cu(SO4)(C5H8N2)4]n, was synthesized using a one-pot reaction of copper powder, anhydrous copper(II) sulfate and 3,5- dimethyl-1H-pyrazole (Hdmpz) in acetonitrile under ambient conditions. The asymmetric unit can be described as a chain consisting of four [Cu(SO4)(Hdmpz)4] formula units that are connected to each other by a 2- sulfato-bridged ligand. The octahedral coordination geometry (O2N4) of all copper atoms is realized by coordination of four pyrazole ligands and two sulfate ligands. Four pyridine-like N atoms of the pyrazole ligands occupy the equatorial positions, while two oxygen atoms of two sulfate ligands are in axial positions. As a result of the sulfate ligand rotation, there is a pairwise alternation of terminal O atoms (which are not involved in coordination to the copper atom) of the SO4 tetrahedra. The CuCu distances within one asymmetric unit are in the range 7.0842 (12)–7.1554 (12) A˚ . The crystal structure is built up from polymeric chains packed in a parallel manner along the b-axis direction. Hirshfeld surface analysis suggests that the most important contributions to the surface contacts are from HH (74.7%), HO/OH (14.8%) and HC/ CH (8.2%) interactions. [ABSTRACT FROM AUTHOR]

A series of bimetallic Mo–Ti–SBA-15-(X), and monometallic Mo/Ti–SBA-15-(X) mesoporous materials were synthesized by direct one-step hydrothermal method. The materials were characterized by XRD, N2 adsorption/desorption, XPS, SEM, EDX, TEM and ICP-AES. XRD results clearly demonstrated that the incorporation of molybdenum and titanium species in the SBA-15 framework little affect the mesoscopic nature of the material. The oxidation state and coordination environment of the active sites was confirmed by XPS. The results revealed that Mo6+ was in octahedral geometry whereas Mo6+ and Ti4+ were in tetrahedral coordination in the SBA-15 framework. The O1s XPS spectrum well established the framework incorporation of molybdenum and titanium species. The catalytic activity of Mo–Ti–SBA-15-(6.5) material was evaluated in the epoxidation of cyclohexene with TBHP. It was found that Mo–Ti–SBA-15-(6.5) catalyst showed high catalytic activity gave a 98% conversion and > 98% selectivity within 8 h. The Mo–Ti–SBA-15-(6.5) was a promising catalyst for the epoxidation of cyclohexene and other olefins. The results showed that the materials containing Ti and Mo exhibited higher catalytic activity than monometallic modified SBA-15. [ABSTRACT FROM AUTHOR]

Phase engineering of CsPbI3 nanocrystals (NCs) is a priority for their optoelectronic applications. So far, the scalable and room‐temperature direct synthesis of black phase CsPbI3 NCs remains an enormous challenge because of the thermal unequilibrium‐induced phase transition. Herein the direct synthesis is reported of metastable β‐CsPbI3 NCs in gram‐scale at room‐temperature in seconds via spontaneous crystallization. The obtained β‐CsPbI3 NCs exhibit good monodispersity, narrow‐band far‐red emission (716 nm, FWHM = 38 nm) as well as a high photoluminescence quantum yield of 62%. The crystallization dynamics of β‐CsPbI3 NCs are revealed through in situ UV–vis absorption and photoluminescence spectra analysis. Finally, a photon‐to‐photon conversion indirect X‐ray detector based on the phase‐stable NCs/polystyrene film is preliminarily demonstrated. This scalable and low‐cost preparation of high‐quality metastable β‐CsPbI3 NCs will pave the way for their future commercial applications in novel optoelectronic devices. [ABSTRACT FROM AUTHOR]

The effect of nitrogen (III) oxide on the process of dinitrogen tetroxide separation in a dephlegmator during preparation of a «crude mixture» (HNO3-N2O4-N2O3-NO2- NO-H2O) in the production of concentrated nitric acid by direct synthesis was studied in this work. The dependence of crystallization onset on the composition of the N2O4-N2O3 mixture and temperature was determined. The refrigerant capable of maintaining the optimal temperature of the N2O4 extraction was suggested. The absence of nitrogen (III) oxide and nitrogen (I) oxide in the autoclave acid was confirmed. [ABSTRACT FROM AUTHOR]