Comparison of surface passivation modification of two mordenite zeolites and their application on the isomerisation of o-ethyltoluene.

During the isomerisation of o-ethyltoluene (O-ET) to produce m-ethyltoluene (M-ET) and p-ethyltoluene (P-ET), it is crucial to improve the isomerisation selectivity and reduce side reactions, such as disproportionation, alkyl transfer, and splitting. In this study, in order to improve the selectivities toward M-ET and P-ET during O-ET isomerisation, both the commercial micropore mordenite (HM) and the prepared micro-mesoporous mordenite (HM-M) were treated through chemical liquid deposition using tetraethyl orthosilicate (TEOS) and 3,5-dimethylphenylmagnesium bromide (DPB), respectively. Thereafter, their structure, porosity, and acidity were characterized via X-ray diffraction, transmission electron microscopy, inductively coupled plasma, N2 sorption, temperature-programmed desorption of ammonia, Fourier-transform infrared spectroscopy of pyridine and 2,6-di-tert-butylpyridine, and thermal analysis. The deposition mechanism of DPB was also discussed. The results showed that TEOS could shrink and block the micropores of mordenite. By contrast, DPB passivated the external surface acidity and did not affect the micropore structure. Moreover, HM modified using DPB significantly shortened the self-coking process, improved the product selectivities for M-PT and P-ET as well as their stability, and prolonged the catalytic life. When the amount of magnesium oxide (MgO) deposited on the HM zeolite was 4%, the product selectivities toward M-ET and P-ET increased from 67.27% to 77.54%, and the yields of M-ET and P-ET increased from 47.57% to 52.98%. However, the performance of the catalyst was not significantly enhanced on the HM-M, owing to the passivation of acidic sites in the mesopores by the TEOS and DPB.

Ce and P123 modified layered double hydroxide (LDH) composite for the synthesis of polypropylene glycol monomethyl ether.

The application of recyclable heterogeneous catalysts in the production of polypropylene glycol monomethyl ether (MPPG) is of great significance to the green chemical industry. In this study, the CeO2/MgAl-LDH(P123) composite was prepared using a nucleation/crystallization isolation method and aqueous reconstruction method, and CeO2/MgAl-LDO(P123) solid base catalyst was prepared by calcination with it as precursor. Thereafter, the morphology, crystal structure, functional group, and thermal stability of the catalyst were characterized using scanning electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, Brunauer-Emmett-Teller analysis, temperature-programmed desorption of carbon dioxide, thermogravimetry, and X-ray photoelectron spectroscopy. The results showed that the catalyst had a larger specific surface area, pore size and pore volume and more basic sites, providing sufficient catalytic activity for the polymerization process. The experimental results for the fabrication of MPPG using CeO2/MgAl-LDO(P123) as catalyst and methanol and propylene oxide as reaction raw materials showed that the conversion of propylene oxide reached 92.04% and the molecular weight of MPPG was 405 under the optimal reaction conditions. Moreover, the conversion of propylene oxide was maintained above 83.69% after the catalyst was reused six times. This study offers a new prospect for the green synthesis of MPPG products.

Ultrasound regulated flexible protein materials: Fabrication, structure and physical-biological properties.

Ultrasound can be used in the biomaterial field due to its high efficiency, easy operation, no chemical treatment, repeatability and high level of control. In this work, we demonstrated that ultrasound is able to quickly regulate protein structure at the solution assembly stage to obtain the designed properties of protein-based materials. Silk fibroin proteins dissolved in a formic acid-CaCl2 solution system were treated in an ultrasound with varying times and powers. By altering these variables, the silks physical properties and structures can be fine-tuned and the results were investigated with Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), gas permeability and water contact angle measurements. Ultrasonic treatment aids the interactions between the calcium ions and silk molecular chains which leads to increased amounts of intermolecular ß-sheets and α-helix. This unique structural change caused the silk film to be highly insoluble in water while also inducing a hydrophilic swelling property. The ultrasound-regulated silk materials also showed higher thermal stability, better biocompatibility and breathability, and favorable mechanical strength and flexibility. It was also possible to tune the enzymatic degradation rate and biological response (cell growth and proliferation) of protein materials by changing ultrasound parameters. This study provides a unique physical and non-contact material processing method for the wide applications of protein-based biomaterials.

Enhancing the Catalytic Properties of Mordenites via an Alkali-Acid Treatment and by Loading Nickel-Cerium during o-Ethyltoluene Isomerization.

The catalytic performance of the selective isomerization of o-ethyltoluene (O-ET) is crucial to increasing the m-ethyltoluene (M-ET) and p-ethyltoluene (P-ET) yields. During the isomerization of O-ET, traditional (commercial) mordenites (HM) are generally limited by a high reaction temperature (235 °C), as well as a low yield of the isomerization product (49.0%). In this study, micro-mesoporous mordenites were obtained by treating commercial mordenites with NaOH, NaOH-HNO3, and NaOH-mixed acid (HNO3-oxalic). Thereafter, their structure, porosity, and acidity were investigated via X-ray diffraction, transmission electron microscopy, inductively coupled plasma, N2 sorption, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy of pyridine, temperature-programmed desorption of ammonia, and nuclear magnetic resonance. Among the various treated samples, the accessibility of the acidic sites and the B/L value of the alkali-mixed HNO3-oxalic one were enhanced, achieving the highest yield (53.6%) and lowest reaction temperature (165 °C), thus significantly reducing the energy consumption of the reaction process. Furthermore, Ni and Ce were successfully loaded via the incipient wetness impregnation of the micro-mesoporous mordenite to significantly prolong the catalytic life. This study affords a new strategy for obtaining high M-ET and P-ET yields from the isomerization of O-ET in mixed C9 aromatics on an industrial scale.

Optimization of pretreatment in pymetrozine production wastewater via reactive distillation and side-stream distillation methods with response surface methodology.

Lots of highly concentrated saline organic wastewater is produced during the pymetrozine production process, causing environmental pollution and waste of resources if discharged directly. Research on actual pymetrozine wastewater treatment is quite scarce. Existing treatment methods of pesticide wastewater usually have disadvantages of long treatment time, low processing efficiency and low recovery rate. To solve these problems, a pretreatment process for pymetrozine wastewater was studied based on material recovery and pollutant degradation. The ammonia conversion process was experimentally investigated by reactive distillation. The reaction product vapor was neutralized and then separated by side-stream distillation. Aspen Plus and response surface methodology were employed to simulate and optimize the operating conditions. Box-Behnken design was used to investigate the individual and interaction effects on methanol purification and sodium acetate removal. Experimental study was carried out on the basis of theoretical simulation data. The result showed that the optimized methanol content on tower top was 99.28% with a yield of 99.95% and methanol content of side withdrawal was 0.01%. The process can be applied for pesticide wastewater treatment to recycle high purity chemical materials, and meets the national sewage comprehensive emission standard.

Synthesis of core-shell Ce-modified mixed metal oxides derived from P123-templated layered double hydroxides.

Layered double hydroxides are a promising platform material which can be combined with a variety of active species based on their characteristic features. Silicon@P123-templated Ce-doped layered double hydroxide (SiO2@CeMgAl-LDH(P123)) composites were synthesized via a facile in situ co-precipitation method, and characterized by TEM, X-ray diffraction, FTIR, XPS, CO2-, etc. in detail. Meanwhile, the calcined powder (SiO2@CeMgAl-LDO(P123)) possessed an excellent core-shell structure and a high surface area inherited from the LDH structure, which led to an outstanding catalytic activity (99.7% conversion of propylene oxide, 92.4% selectivity of propylene glycol methyl ether) under mild reaction conditions (120 °C). Cerium oxide provides a large number of oxygen vacancies and significantly improves the medium basic strength of the material, which facilitates the selective ring-opening of PO. Furthermore, the introduction and removal of P123 make the cerium oxide uniformly dispersed on the LDH layers, providing more reaction sites for the reaction of methanol and propylene oxide. The core-shell structure prepared by the in situ co-precipitation method could solve the shortcomings of agglomeration of layered double hydroxides and prolong the catalytic life evidently.

A new highly active La2O3-CuO-MgO catalyst for the synthesis of cumyl peroxide by catalytic oxidation.

In this study, different magnesium, copper, lanthanide single metal, and composite multimetal oxide catalysts were prepared via the coprecipitation route for the aerobic oxidation of cumene into cumene hydroperoxide. All catalysts were characterized using several analytical techniques, including XRD, SEM, EDS, FT-IR, BET, CO2-TPD, XPS, and TG-DTG. La2O3-CuO-MgO shows higher oxidation activity and yield than other catalysts. The results of XRD and SEM studies show that the copper and magnesium particles in the catalyst are smaller in size and have a distribution over a larger area due to the introduction of the lanthanum element. The CO2-TPD results confirmed that the catalyst has more alkali density and alkali strength, which can excite active sites and prevent the decomposition of cumene hydroperoxide. XPS results show that due to the promotional effect of La2O3, there are more lattice and active oxygen species in the catalyst, which can effectively utilize the lattice defects under the strong interaction between metal oxides for rapid adsorption and activation, thus improving the oxidation performance. Besides, La2O3-CuO-MgO exhibits good stability and crystalline structure due to its high oxygen mobility inhibiting coking during the cycle stability test. Finally, the possible reaction pathway and promotional mechanism on La2O3-CuO-MgO in cumene oxidation are proposed. We expect this study to shed more light on the nature of the surface-active site(s) of La2O3-CuO-MgO catalyst for cumene oxidation and the development of heterogeneous catalysts with high activity in a wide range of applications.

Organic and inorganic model soil fractions instigate the formation of distinct microbial biofilms for enhanced biodegradation of benzo[a]pyrene.

This study conducted the sorption and biodegradation of benzo[a]pyrene (BaP) by microbial biofilm communities developed on proxies for materials typically found in soils. The half-life of BaP was 4.7 and 2.3 weeks for biofilms on the inorganic carrier (BCINOR, montmorillonite) and on the organic carrier (BCOR, humic acid), respectively. In contrast, the half-life was 7.0 weeks for specialized planktonic cultures (PK). The exposure to BaP caused the development of lipid inclusion bodies inside the bacteria of the PK systems and biofilms of the BCINOR, but not on the biofilms of the BCOR system. Interestingly, the BCOR displayed not only the greatest BaP sorption capacity but also the greatest bacterial density and membrane integrity and the shortest bacteria-to-bacteria distances, which were consistent with the increased production of cell surface extracellular polymeric substances on the BCOR. Both carriers caused a noticeable shift in the bacterial genera during the biodegradation of the BaP. The BCINOR selected for Rhodococcus, Brucella, Chitinophaga, and Labrys, whereas the BCOR favored Rhodococcus and Dokdonella. It indicated that ultra-structure and BaP degradation within the organic carrier-attached biofilms differed from the inorganic ones, and suggested that the microstructural heterogeneity and microbial biodiversity from biofilms on the organic carrier promoted biodegradation.

Recent Advances in Electrospun Sustainable Composites for Biomedical, Environmental, Energy, and Packaging Applications.

Electrospinning has gained constant enthusiasm and wide interest as a novel sustainable material processing technique due to its ease of operation and wide adaptability for fabricating eco-friendly fibers on a nanoscale. In addition, the device working parameters, spinning solution properties, and the environmental factors can have a significant effect on the fibers' morphology during electrospinning. This review summarizes the newly developed principles and influence factors for electrospinning technology in the past five years, including these factors' interactions with the electrospinning mechanism as well as its most recent applications of electrospun natural or sustainable composite materials in biology, environmental protection, energy, and food packaging materials.

Evaluation of the binding of natural products with thrombin binding aptamer G-quadruplex using electrospray ionization mass spectrometry and spectroscopic methods.

A 15-mer thrombin-binding aptamer (TBA) was discovered with specificity for thrombin. It forms a unique G-quadruplex (G4), which is postulated to be the molecular basis for its binding specificity. Many analytical methods make use of affinity binding between the thrombin and TBA as they form a very stable complex. We develop a strategy to stabilize TBA/G4's structure by introducing G4-interactive molecules, which may enhance its ability to recognize the target. Herein, a fast screening ESI-MS assay was employed to determine potential binding of natural products molecules with the TBA/G4 complex. The experimental results showed that four investigated natural alkaloids had apparent binding affinities. One of them, jatrorrhizine (L1), has been shown to bind strongly to the TBA/G4 mainly in 1:2 M ratio. Once the working conditions were established, the interaction of the jatrorrhizine with the TBA/G4 was explored using a combination of ESI-MS and spectroscopic techniques. Ligand-induced effects on TBA/G4 structure and its stability were examined by means of circular dichroism (CD). Jatrorrhizine inducing the G4 formation seems also to be the more effective in terms of thermal stabilization under the experimental conditions used. Both results of UV and fluorescence experiments undoubtedly showed a good binding affinity with the binding constant around 105 L mol-1. The stacking interactions of jatrorrhizine with the G-tetrads in TBA/G4 were further confirmed by competition experiment. ESI-MS was carried out to determine the coexistence of 1:1 and 1:2 complexes in TBA/G4-L1 system, and showed a dynamical shift from 1:1 to 1:2 complex in minutes.

Exploring the Structural Transformation Mechanism of Chinese and Thailand Silk Fibroin Fibers and Formic-Acid Fabricated Silk Films.

Silk fibroin (SF) is a protein polymer derived from insects, which has unique mechanical properties and tunable biodegradation rate due to its variable structures. Here, the variability of structural, thermal, and mechanical properties of two domesticated silk films (Chinese and Thailand B. Mori) regenerated from formic acid solution, as well as their original fibers, were compared and investigated using dynamic mechanical analysis (DMA) and Fourier transform infrared spectrometry (FTIR). Four relaxation events appeared clearly during the temperature region of 25 °C to 280 °C in DMA curves, and their disorder degree (fdis) and glass transition temperature (Tg) were predicted using Group Interaction Modeling (GIM). Compared with Thai (Thailand) regenerated silks, Chin (Chinese) silks possess a lower Tg, higher fdis, and better elasticity and mechanical strength. As the calcium chloride content in the initial processing solvent increases (1%⁻6%), the Tg of the final SF samples gradually decrease, while their fdis increase. Besides, SF with more non-crystalline structures shows high plasticity. Two α- relaxations in the glass transition region of tan δ curve were identified due to the structural transition of silk protein. These findings provide a new perspective for the design of advanced protein biomaterials with different secondary structures, and facilitate a comprehensive understanding of the structure-property relationship of various biopolymers in the future.

Evaluation of bacterial biodegradation and accumulation of phenanthrene in the presence of humic acid.

This study evaluated the effect of humic acid (HA) on physicochemical properties of bacterial surfaces and on mass transfer of polycyclic aromatic hydrocarbons (PAHs) from aqueous phase into intracellular bacteria. Due to this process' potential for bacterial degradation, using Sphingobium sp. PHE3, degradation of phenanthrene (PHE) was compared in HA and non-HA sets. The results showed that approximately 51.1% of PHE at a concentration of 102.0 mg L-1 was biodegraded in the non-HA sets, whereas almost all PHE was biodegraded with HA after 72 h. Interestingly, PHE that accumulated in the intracellular bacteria reached 3.80 mg L-1 for the HA sets, which was significantly higher than that of non-HA. Lipid inclusion bodies appeared when Sphingobium sp. PHE3 was treated with HA. The results were further confirmed by the enhanced bacterial surface sorption capacity for the HA sets. Therefore, we concluded that added HA not only act as carriers and biosurfactants facilitating PHE uptake but also adjust bacteria cell wall properties for internalizing PHE, which ultimately overcame the PHE bioavailability resulting in enhanced biodegradation.

Preparation and characterization of Zr(SO4)2/TiO2 catalyst.

Solid acid Zr(SO4)2/TiO2 catalyst has highly catalytic activity, and has non-corrosiveness to equipment. It is separated from production expediently. As the above advantages, the influence of Zr(SO4)2 loading amount, calcination temperature, and calcination time on the solid acid Zr(SO4)2/TiO2 catalyst preparation process is discussed. The experimental condition is optimized by orthogonal test, the result indicate that Zr(SO4)2 load is 65%, calcination temperature is 430°C, and calcination time is 2.5 h. Solid acid catalyst Zr(SO4)2/TiO2 is analyzed and characterized by FT-IR, XRD and SEM. The results will provide the experimental condition for enlarging experimental study.

4-Dimethyl-amino-N'-(2-meth-oxy-benzyl-idene)benzohydrazide.

In the title mol-ecule, C(17)H(19)N(3)O(2), the dihedral angle between the two benzene rings is 14.05 (15)°. In the crystal, mol-ecules are linked through inter-molecular N-H⋯O hydrogen bonds, forming chains along b.

N'-(4-Diethyl-amino-2-hy-droxy-benzyl-idene)-4-(dimethyl-amino)-benzo-hydrazide methanol monosolvate.

The title compound, C(20)H(26)N(4)O(2)·CH(3)OH, was prepared by the reaction of 4-diethyl-amino-2-hy-droxy-benzaldehyde with 4-(dimethyl-amino)-benzohydrazide. The dihedral angle between the two benzene rings is 13.6 (3)° and an intra-molecular O-H⋯N hydrogen bond generates an S(6) ring. In the crystal, the hydrazone and methanol mol-ecules are linked through inter-molecular O-H⋯O and N-H⋯O hydrogen bonds, forming chains along a.