Synthesis, Characterization and Optical Morphology of ZnO Nanoparticles

The ZnO molecule plays an important role in the industry due to it special features, anti-corrosion anti-bacterial properties, as well as due to its low electrical conductivity and heat resistance. In these experimental researches, the sol-gel method was chosen, which enables control of nucleation, aging and growth of particles in the solution. ZnO synthesis was prepared utilizing chemical method with Zinc acetate dyhidrate and NaOH with the appropriate methanol solvent and heating (60˚C). The methods used in identification and characterization are FTIR, UV/VIS, OPTICAL MICROSCOPY, SEM and XRD. The FTIR spectra of synthesized ZnO with corresponding ones show characteristic bands at the corresponding wavelengths, which confirm the presence of ZnO nanoparticles. SEM characterization of ZnO shows the morphology of needle-shaped nanoparticles. XRD spectar in this research by chemical method indicates the particle size of 17.76 nm.

Solriamfetol impurities:Synthesis,characterization,and analytical method(UPLC-UV)validation

Given that impurities may affect the quality and safety of drug products,impurity identification and profiling is an integral part of drug quality control and is particularly important for newly developed medications such as solriamfetol,which is used to treat excessive daytime sleepiness.Although the highperformance liquid chromatography analysis of commercial solriamfetol has revealed the presence of several impurities,their synthesis,structure elucidation,and chromatographic determination have not been reported yet.To bridge this gap,we herein identified,synthesized,and isolated eight processrelated solriamfetol impurities,characterized them using spectroscopic and chromatographic techniques,and proposed plausible mechanisms of their formation.Moreover,we developed and validated a prompt impurity analysis method based on ultrahigh-performance liquid chromatography with UV detection,revealing that its selectivity,linearity,accuracy,precision,and quantitation limit meet the acceptance criteria of method validation stipulated by the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use.Thus,the developed method was concluded to be suitable for the routine analysis of solriamfetol substances.

One-pot synthesis of bimetallic CeCu-SAPO-34 for high-efficiency selective catalytic reduction of nitrogen oxides with NH_(3) at low temperature

NH_(3) selective catalytic reduction(SCR) has been widely recognized as a promising technique for reducing nitrogen oxides from diesel vehicle exhausts. High-efficiency SCR catalysts that could perform at low temperatures are essential to denitration. In this work, a series of bimetallic CeCu-SAPO-34 molecular sieves were synthesized by one-step hydrothermal method. The Ce Cu-SAPO-34 maintained good crystallinity and a regular hexahedron appearance of Cu-SAPO-34 after introducing Ce species, while exhibiting a higher specific surface area and pore volume. The as-prepared CeCu-SAPO-34 with 0.02%(mass) Ce constituent exhibited the best catalytic activity below 300℃ and a maximum NO_(x) conversion of 99% was attained;the NO_(x) removal rates of more than 68% and 94% were achieved at 150℃ and 200℃, respectively. And the introduction of cerium species in Cu-SAPO-34 improves the low-temperature hydrothermal stability of the catalyst towards NH_(3)-SCR reaction. Additionally, the introduced Ce species could enhance the formation of abundant weak Br?nsted acid centers and promote the synergistic effect between CuO grains and isolated Cu^(2+) to enhance the redox cycle, which benefit the NH_(3)-SCR reaction.This work provides a facile synthesis method of high-efficiency SCR denitration catalysts towards diesel vehicles exhaust treatment under low temperature.

Synthesis strategies of covalent organic frameworks: An overview from nonconventional heating methods and reaction media

Covalent organic frameworks(COFs), as an emerging class of porous crystalline materials constructed by covalent links between the building monomers, have gained tremendous attention. Over the past 15 years, COFs have made rapid progress and substantial development in the chemistry and materials fields. However, the synthesis of COFs has been dominated by solvothermal methods for a long time and it usually involves high temperature, high pressure and toxic organic solvents, which created many challenges for environmental considerations. Recently,the exploration of new approaches for facile fabrication of COFs has aroused extensive interest. Hence, in this review, we comprehensively describe the synthetic strategies of COFs from the aspects of nonconventional heating methods and reaction media. In addition, the advantages,limitations and properties of the preparation methods are compared. Finally, we outline the main challenges and development prospects of the synthesis of COFs in the future and propose some possible solutions.

Crystal Structures of Two Compounds from a Rapid and One-pot Synthesis Method

Compounds 1 （C17H22N2,Mr =254.37） and 2 （C13H16N2,Mr=200.28） have been synthesized and their crystal structures were determined by single-crystal X-ray diffraction.Crystal 1 belongs to triclinic,space group P（1） with a =6.524（2）,b =8.987（3）,c =12.746（5） A,α =95.220（7）,β =90.055（6）,γ =104.431（6）°,V =720.5（4） A^3,Z =2,Dc =1.173 g/cm^3,μ（MoKα） =0.069 mm1,F（000） =276,R =0.0578 and wR =0.1221 for 1487 observed reflections Ⅰ 〉 2o（Ⅰ）.Crystal 2 is of tetragonal system,space group Ⅰ41/a with a =20.763（10）,b =20.763（10）,c =11.427（6） A,V=4926（4） A3,Z =16,Dc =1.080 g/cm^3,μ（MoKα） =0.065 mm-1,F（000） =1728,R =0.0581 and wR =0.1288 for 1408 observed reflections with Ⅰ 〉 2σ（Ⅰ）.Although the two compounds are similar with the same pyrazole and benzene ring units,X-ray analysis reveals that their structures are completely different maybe caused by steric effects.

Type Synthesis of 4-DOF Parallel Kinematic Mechanisms Based on Grassmann Line Geometry and Atlas Method

Many methods are proposed to deal with the type synthesis of parallel kinematic mechanisms（PKMs）, but most of them are less intuitive to some extent. Thus, to propose a concise and intuitive type synthesis method for engineering application is a very challenging issue, which should be further studied in the field. Grassmann line geometry, which can investigate the dimensions of spatial line-clusters in a concise way, is taken as the mathematic foundation. Atlas method is introduced to visually describe the degrees of freedom（DOFs） and constraints of a mechanism, and the dual rule is brought in to realize the mutual conversion of the freedom-space and constraint-space. Consequently, a systematic method based on Grassmann line geometry and Atlas method is generated and the entire type synthesis process is presented. Three type 4-DOF PKMs, i.e., 1T3R, 2T2R and 3T1R（T： translational DOF; R： rotational DOF）, are classified according to the different combinations of the translational DOFs and rotational DOFs. The type synthesis of 4-DOF PKMs is carried out and the possible configurations are thoroughly investigated. Some new PKMs with useful functions are generated during this procedure. The type synthesis method based on Grassmann line geometry and Atlas method is intuitive and concise, and can reduce the complexity of the PKMs＇ type synthesis. Moreover, this method can provide theoretical guidance for other PKMs＇ type synthesis and engineering application. A novel type synthesis method is proposed, which solves the existing methods＇ problems in terms of complicated, not intuitive and unsuitable for practical application.

One-pot synthesis and characterization of a new, branched polycarbosilane bearing allyl groups

A highly branched polycarbosilane bearing allyl groups has been prepared by a one-pot synthesis with chloromethyltrichlorosilane, chloromethylmethyldichlorosilane and allyl chloride as the starting materials. The resultant polymer, with the approximate formula [SiH1.2(CH3)0.71(CH2CHCH2)0.09CH2]n, has been characterized by 1H, 13C, and 29Si NMR, GPC, TG and elemental analysis. It could be cross-linked thermally at 170 °C in the absence of oxygen. Pyrolysis of the polymer gave a ceramic with a yield of about 70%.

One-pot synthesis of 2-aminothiazoles in PEG-400

A facile one-pot synthesis of 2-aminothiazoles has been carried in PEG-400 as a greener medium at room temperature.This method avoids the use of lachrymatric a-bromoketones as well as the volatile,toxic organic solvents.

Synthesis and Characterization of Y-Doped Mesoporous CeO_2 Using A Chemical Precipitation Method

Using cetyltrimethylammonium bromide （CTAB） as the template agent, cerium nitrate as the cerium resource, yttrium nitrate as the yttrium resource, and ammonium carbonate as the precipitating agent, mesoporous CeO2 powders doped with different yttrium contents were successfully synthesized using a chemical precipitation method, under an alkalescent condition. Properties of the obtained samples were characterized and analyzed with X-ray diffraction （XRD）, energy dispersive analysis of X-rays （EDAX）, transmission electron microscopy （TEM）, infrared （IR） absorbance, and the BET method. For the prepared samples with 20% （molar ratio） Y-doped content, a BET specific surface area of 106. 6 m^2 · g^- 1, with an average pore size of3~27 nm were obtained. XRD patterns showed that the doped samples were with a cubic fluorite structure. TEM micrographs revealed that the doped samples showed a spherical morphology with a diameter ranging from 20 to 30 nm and a round pore shape. IR results indicated that the Ce-O-Ce vibration intensity decreased as the Y-doped content increased. N2 adsorption-desorption isotherms showed that the samples possessed typical mesopore characteristics. The average pore size of the samples decreased alter mesoporous CeO2 was doped with yttrium, and the average pore size decreased largely as the Y-doped content increased.

Facile synthesis of hydrochar-supported catalysts from glucose and its catalytic activity towards the production of functional amines

Since the utilization of abundant biomass to develop advanced materials has become an utmost priority in recent years,we developed two sustainable routes(i.e.,the impregnation method and the one-pot synthesis)to prepare the hydrochar-supported catalysts and tested its catalytic performance on the reductive amination.Several techniques,such as TEM,XRD and XPS,were adopted to characterize the structural and catalytic features of samples.Results indicated that the impregnation method favors the formation of outer-sphere surface complexes with porous structure as well as well-distributed metallic nanoparticles,while the one-pot synthesis tends to form the inner-sphere surface complexes with relatively smooth appearance and amorphous metals.This difference explains the better activity of catalysts prepared by the impregnation method which can selectively convert benzaldehyde to benzylamine with an excellent yield of 93.7%under the optimal reaction conditions;in contrast,the catalyst prepared by the one-pot synthesis only exhibits a low selectivity near to zero.Furthermore,the gram-scale test catalyzed by the same catalysts exhibits a similar yield of benzylamine in comparison to its smaller scale,which is comparable to the previously reported heterogeneous noble-based catalysts.More surprisingly,the prepared catalysts can be expediently recycled by a magnetic bar and remain the satisfying catalytic activity after reusing up to five times.In conclusion,these developed catalysts enable the synthesis of functional amines with excellent selectivity and carbon balance,proving cost-effective and sustainable access to the wide application of reductive amination.

One-pot Synthesis of Lewis Acidic Ionic Liquids for Friedel-Crafts Alkylation

Novel Lewis acidic ionic liquids containing thionyl cations and chloroaluminate anions were obtained by one-pot synthesis for the first time. Their acidities were determined by acetonitrile probe on IR spectrography. The ionic liquids were used as catalyst for Friedel-Crafts alkylation of benzene and 1-dodecene. The turnovers of l-dodecene were higher than 99%. Monoalkylbenzene selectivity was 98%, while the 2-substituent product selectivity was 45%.

Synthesis of potassium hexatitanate whiskers using hydrothermal method

High quality potassium hexatitanate whiskers were hydrothermally synthesized in one step under moderate temperature and pressure conditions. Effects of the titanium source and reaction conditions on the hydrothermal reaction rate, product phase component, and morphology of whiskers were investigated. The results show that the reactivity of hydrated titania, anatase TiO2, and rutile TiO2 with KOH decreases in turn, and with hydrated titania as titanium source, it is difficult to obtain potassium hexatitanate whiskers with good morphology. In contrast, uniform potassium hexatitanate whiskers with a length of 10-20 μm and a diameter of 200-700 nm were obtained using anatase TiO2 as titanium source. The investigation demonstrates that the initial KOH concentration, annealing temperature and time, molar ratio of K2O/TiO2, etc. significantly affect the morphology of the as-synthesized whiskers. The optimized synthesis condition is as follows： anatase as a titanium source 10 wt.% KOH solution; annealing temperature and time of 300℃ and 5 h, respectively; K2O/TiO2 molar ratio of 5, etc. A rhombic potassium hexatitanate was prepared under the optimum condition and the whisker grew along the [110] direction. The reaction mechanism was discussed.

Fischer–Tropsch synthesis using Co and Co-Ru bifunctional nanocatalyst supported on carbon nanotube prepared via chemical reduction method

We used a chemical reduction method to synthesize the catalysts of cobalt(Co) and cobalt-ruthenium(Co-Ru) bifunctional supported on carbon nanotubes(CNTs) for Fischer–Tropsch synthesis(FTS) in a fixedbed reactor. These Co-Ru/CNTs catalysts were synthesized with various weight proportions of Ru/Co(0.1 to 0.4 wt%) with keeping a fixed amount of cobalt(10 wt%). Moreover, for comparison purpose, CNTs supported Co-and Co(Ru)-based catalysts at same loading as the above catalysts were prepared through impregnation method. We characterize the present catalysts through the various techniques such as Energy–dispersive X-ray(EDX), Transmission Electron Microscopy(TEM), Brunauer–Emmett–Teller(BET),Hydrogen-Temperature-Programmed Reduction(H_2-TPR), Hydrogen-Temperature-Programmed Desorption(H_2-TPD) and O_2 titration. Thus using the chemical reduction method, a narrow particle size distribution was obtained so that the small cobalt particles were confined inside the CNTs. The Co-based catalyst prepared by impregnation was compared with the Co-Ru catalysts at the same loading. The results demonstrated that the use of chemical reduction method led to decrease the average Co oxide cluster size to8.7 nm so that the reduction enhanced about 24% and stabilized an earlier time at the stream. Among the prepared catalysts, the results indicated that the Co-Ru/CNTs catalysts demonstrated high catalytic activity with the highest long-chain hydrocarbons(C_(5+)), selectivity up to 74.76%, which was higher than those we obtained by the Co-Ru/γ-Al_2O_3(61._20%), Co/CNTs(43.68%) and Co/γ-Al_2O_3(37.69%). At the same time, comparing with those catalyst synthesized by impregnation, the use of chemical reduction led to enhancement of the C_(5+) selectivity from 59.30% to 68.83% and increment in FTS rate about 11% for the Co-Ru/CNTs catalyst.

Efficient one-pot synthesis of 1,3-diaryl-3H-benzo[f]chromenes using ferric hydrogensulfate

An efficient and easy method for one-pot three-component synthesis of l,3-disubstituted-3H-benzo[f]chromenes by the condensation of naphtol,aromatic aldehyde derivatives and phenylacetylene in the presence of ferric hydrogensulfate[Fe（HSO4）3], has been described.The catalyst displayed high activity which afforded the corresponding 1,3-disubstituted-3H-benzo[f]chromenes in satisfying yields.Alkyl-substituted phenols were examined and the corresponding benzopyran derivatives were synthesized in moderate yields.Heterogeneous nature of the using catalyst made it reusable for further chemical reactions.

Adding Sub-chain Method for Structural Synthesis of Planar Closed Kinematic Chains

For at least the past five decades,structural synthesis has been used as a main means of finding better mechanisms with some predefined function.In structural synthesis,isomorphism identification is still a problem unsolved well,and to solve this problem is very significant to the design of new mechanisms.According to the given degree of freedom（DOF） and link connection property of planar closed chain mechanisms,vertex assortment is obtained.For solving the isomorphism problem,a method of the adding sub-chains is proposed with the detailed steps and algorithms in the synthesizing process.Employing this method,the identification code and formation code of every topological structure are achieved,therefore many isomorphic structures could be eliminated in time during structural synthesis by comparing those codes among different topological graphs,resulting in the improvement of synthesizing efficiency and accuracy,and the approach for eliminating rigid sub-chains in and after the synthesizing process is also presented.Some examples are given,including how to add sub-chains,how to detect simple rigid sub-chains and how to obtain identification codes and formulation codes et al.Using the adding sub-chain method,the relative information of some common topological graphs is given in the form of table.The comparison result is coincident with many literatures,so the correctness of the adding sub-chain method is convinced.This method will greatly improve the synthesizing efficiency and accuracy,and has a good potential for application.

A New Method for Type Synthesis of 2R1T and 2T1R 3-DOF Redundant Actuated Parallel Mechanisms with Closed Loop Units

The current type synthesis of the redundant actuated parallel mechanisms is adding active-actuated kinematic branches on the basis of the traditional parallel mechanisms,or using screw theory to perform multiple getting intersection and union to complete type synthesis.The number of redundant parallel mechanisms obtained by these two methods is limited.In this paper,based on Grassmann line geometry and Atlas method,a novel and effective method for type synthesis of redundant actuated parallel mechanisms(PMs)with closed-loop units is proposed.Firstly,the degree of freedom(DOF)and constraint line graph of the moving platform are determined successively,and redundant lines are added in constraint line graph to obtain the redundant constraint line graph and their equivalent line graph,and a branch constraint allocation scheme is formulated based on the allocation criteria.Secondly,a scheme is selected and redundant lines are added in the branch chains DOF graph to construct the redundant actuated branch chains with closed-loop units.Finally,the branch chains that meet the requirements of branch chains configuration criteria and F&C(degree of freedom&constraint)line graph are assembled.In this paper,two types of 2 rotational and 1 translational(2R1T)redundant actuated parallel mechanisms and one type of 2 translational and 1 rotational(2T1R)redundant actuated parallel mechanisms with few branches and closed-loop units were taken as examples,and 238,92 and 15 new configurations were synthesized.All the mechanisms contain closed-loop units,and the mechanisms and the actuators both have good symmetry.Therefore,all the mechanisms have excellent comprehensive performance,in which the two rotational DOFs of the moving platform of 2R1T redundant actuated parallel mechanism can be independently controlled.The instantaneous analysis shows that all mechanisms are not instantaneous,which proves the feasibility and practicability of the method.

A bifunctional and recyclable catalyst:Amine and ionic liquid grafting on MOFs for the one-pot synthesis of N-aryl oxazolidin-2-ones

A bifunctional heterogeneous catalyst was designed and synthesized,denoted DMEDA/IL–NH2-MIL-101.The structure and physical-chemical characterization of DMEDA/IL–NH2-MIL-101 and its precursors were characterized by SEM,N2 adsorption-desorption,XPS,FT-IR,PXRD,elemental analysis,and TGA techniques.The date showed that the two catalytic components of N,N-dimethylethylenediamine(DMEDA)and 1-butyl-3-methylimidazolium bromide(BmimBr)were chemically immobilized in NH2-MIL-101 nanocages.The amine of DMEDA was grafted onto carrier NH2-MIL-101 by N–Cr coordinate covalent bonds and the ionic liquid of BmimBr(IL(Br-))was anchored in the NH2-MIL-101 nanocages by'ship-in-a-bottle'method,in which the amidogen of NH2-MIL-101 condensed with N,N-carbonyldiimidazole(CDI)firstly,and then alkylated with 1-bromo butane.This novel heterogeneous catalyst with two different active sites can efficiently catalyze the synthesis of N-aryl oxazolidin-2-ones from carbon dioxide(CO2),epoxides,and anilines in one-pot under mild solvent-free conditions.It not only showed good stability and recoverability after five cycles but also exhibited shape selectivity for the substrate due to the synergic catalysis of amine,ionic liquid,and NH2-MIL-101.This novel bifunctional material is a promising solid catalyst for the green synthesis of N-aryl oxazolidin-2-ones.

One-pot synthesis of network supported catalyst using supramolecular gel as template

A simple and general strategy is described for preparing network supported catalyst through a one-pot synthetic procedure using supramolecular gel as template.This procedure directly attaches ligand to support during fabricating the support.Using this strategy,supported CuBr/di-（2-picolyl） amine catalyst with U-shaped fibrillar network was prepared and used in atom transfer radical polymerization of methyl methacrylate.XPS and SEM characterization of the catalyst revealed homogeneous distribution of ligand,sufficient reactive sites,adequate mechanical strength and macroporosity.The polymerization results demonstrated high activity and reusability of such catalyst.This strategy might be extended to other supported catalysts used in column reactors.