Amine-grafted on lanthanide metal-organic frameworks:Three solid base catalysts for Knoevenagel condensation reaction

A post-synthetic modification strategy has been used to prepare three solid base catalysts, including Er（btc）（ED）075（H2O）0.25 （2, btc = 1,3,5-benzenetricarboxylates, ED = 1,2-ethanediamine）, Er（btc）（PP）0.55（H20）0.45 （3, PP = piperazine）, and Er（btc）（DABCO）0.15（H2O）0.85 （4, DABCO = 1,4- diazabicyclo[2.2.2]octane）, by grafting three different diamines onto the coordinatively unsaturated Er（III） ions into the channels of the desolvated lanthanide metal-organic framework （Er（otc））. The resulting metal-organic frameworks were characterized by elemental analysis, thermogravimetric analysis, powder X-ray diffraction, and N2 adsorption. Based on its higher loading ratio of the diamine, as well as its greater stability and porosity, catalyst 2 exhibited higher catalytic activity and reusability than catalysts 3 and 4- for the Knoevenagel condensation reaction. The catalytic mechanism of 2 has also been investigated using size-selective catalysis tests.

Simulation of biodiesel industrial production via solid base catalyst in a fixed-bed reactor

Biodiesel industrial production based on a solid base catalyst in a fixed-bed was simulated. The lab and bench scale experiments were carded out effectively, in which the kinetic model is established and it can describe the transesterification reaction well. The Antoine equation of biodiesel is regressed with the vapor-liquid data cited of literature. The non-random two liquid （NRTL） model is applied to describe the system of fatty acid methyl ester （FAME）, methanol and glycerol and parameters are obtained. The Ternary phase map is obtained from Aspen Plus via the liquid-liquid equilibrium （LLE） data. In order to describe the production in a fixed-bed performs in industrial scale after being magnified 1 000 times, the Aspen Plus simulation is employed, where two flowsheets are simulated to predict material and energy consumption. The simulation results prove that at least 350. 42 kW energy consumption can be reduced per hour to produce per ton biodiesel compared with data reported in previous references.

Solid base catalysts derived from Ca-M-Al(M = Mg, La, Ce, Y) layered double hydroxides for dimethyl carbonate synthesis by transesterification of methanol with propylene carbonate

Composite solid base catalysts derived from Ca‐M‐Al(M=Mg,La,Ce,Y)layered double hydroxides(LDH)were synthesized,characterized and applied to the transesterification of methanol with propylene carbonate.X‐ray diffraction analyses of the catalysts show that all of the catalysts were in the form of composite oxides.Compared with the Ca‐Al LDH catalyst,the specific surface areas and pore volumes of the catalysts were increased with the introduction of Mg,La or Ce.The catalytic performance of these catalysts increases in the order of Ca‐Y‐Al<Ca‐Al<Ca‐Ce‐Al<Ca‐La‐Al<Ca‐Mg‐Al,which is consistent with the total surface basic amounts of these materials and the formation of especially strong basic sites following modification with Mg and La.The Ca‐Mg‐Al catalyst shows the highest(Ca+Mg):Al atomic ratio,indicating that it likely contains more unsaturated O2?ions,providing it with the highest concentration of very strong basic sites.The recyclability of these catalysts is improved following the addition of Mg,La,Ce or Y,with the Ca‐Mg‐Al maintaining a high level of activity after ten recycling trials.X‐ray diffraction analyses of fresh and used Ca‐Mg‐Al demonstrate that this catalyst is exceptionally stable,which could be of value in practical applications related to heterogeneous catalysis.

NEW SOLID BASE DERIVED FROM AIPO4-5 SUPPORTED KF

Dispersion of KF on AlPO4-5 molecular sieve created basic sites and caused 1654 cm- band of bidentate carbonate in CO2 adsorption.After pre-treated above 823K. 5%KF/AlPO4-5exhibited basic catalytic activity in the isomerization of butenes at 273K. and the activity increasedwith the pre-treatment temperature up to 923K.

Atomically dispersed calcium as solid strong base catalyst with high activity and stability

Solid strong base catalysts are highly attractive for diverse reactions owing to their advantages of neglectable corrosion,facile separation,and environmental friendliness.However,their widespread applications are impeded by basic components aggregation and low stability.In this work,we fabricate single calcium atoms on graphene(denoted as Ca1/G)by use of a redox strategy for the first time,producing solid strong base catalyst with high activity and stability.The precursor Ca(NO_(3))_(2)is first reduced to CaO at 400℃ by the support graphene,forming CaO/G with conventional basic sites,and the subsequent reduction at 850℃results in the generation of Ca1/G with atomically dispersed Ca.Various characterizations reveal that Ca single atoms are anchored on graphene in tetra-coordination(Ca-C_(2)-N_(2))where N is in situ doped from Ca(NO_(3))_(2).The atomically dispersed Ca,along with their anchoring on the support,endow Ca1/G with high activity and stability toward the transesterification reaction of ethylene carbonate with methanol.The turnover frequency value reaches 128.0 h^(-1)on Ca1/G,which is much higher than the traditional counterpart CaO/G and various reported solid strong bases(2.9-46.2 h^(-1)).Moreover,the activity of Ca1/G is well maintained during 5 cycles,while 60%of activity is lost for the conventional analogue CaO/G due to the leaching of Ca.

Mesoporogen-free synthesis of hierarchical sodalite as a solid base catalyst from sub-molten salt-activated aluminosilicate

A rapid and environmentally friendly approach to synthesize hierarchical sodalite from natural aluminosilicate mineral without the involvement of any mesoporogen or post-synthesis treatment was developed.This strategy involves three important steps:the first is the depolymerization of an aluminosilicate mineral into highly reactive silicon and aluminum species with ideal meso-scale structures through activation of a sub-molten salt.The second step is the hydrolysis and condensation of the activated aluminosilicate mineral into zeolitic precursors that also have a meso-scale structure.The third is the rapid zeolitization of the zeolitic precursors through the reversed crystal growth route at room temperature and ambient pressure to form hierarchical sodalite.The physicochemical properties of the as-synthesized sodalite were systematically characterized,and the formation mechanism of the hierarchical pore structure was discussed.When used as a solid base catalyst for Knoevenagel condensation,the as-synthesized sodalite and its potassium ion-exchanged product with hierarchical micro-meso-macroporous structure both exhibited high catalytic activity and product selectivity.

Synthesis of dimethyl adipate from cyclopentanone and dimethyl carbonate over solid base catalysts

A facile route for the synthesis of dimethyl adipate （DAP） from cyclopentanone and dimethyl carbonate （DMC） in the pres- ence of solid base catalysts has been developed. It was found that the intermediate carbomethoxycyclopentanone （CMCP） was produced from cyclopentanone with DMC in the first step, and then CMCP was further converted to DAP by reacting with a methoxide group. The role of the basic catalysts can be mainly ascribed to the activation of cyclopentanone via the abstraction of a proton in the a-position by base sites, and solid bases with moderate strength, such as MgO, favor the formation of DAP.

Transesterification of glyceryl tributyrate with methanol using strontium borate as the solid base catalyst

Four kinds of strontium borates were prepared and characterized by XRD, SEM, EDS, TG-DTA and Hammett titration method and their catalytic activities were examined in the transesterification of glyceryl tributyrate with methanol for the first time. The separate effects of the molar ratio of methanol to oil, the reaction time, and reusability were investigated. In addition, the catalytic activities of Sr（OH）2 and SrCO3 were also examined for the comparison. The results showed that the basicity and catalytic activity of these catalysts were decreased as the following order： Sr（OH）2 〉 SrB2O4·4H2O 〉 SrB6O10·5H2O 〉 SrB2O4 〉 SrB6O10 〉 SrCO3, and the reusability decreases as the following order： anhydrous strontium borates （SrBgO4, SrB6O10） 〉 hydrated strontium borates （SrB2O4·4H2O, SrB6O10·5H2O） 〉 Sr（OH）〉 The results indicate that the SrB2O4·4H2O with regular morphology, which was obtained at low temperature by a simple preparation method, might be as one kind of good potential alkaline earth salts catalyst for transesterification. Moreover, the possible reaction mechanism is proposed and analyzed.

Development of solid base catalyst X/Y/MgO/-Al_(2)O_(3) for optimization of preparation of biodiesel from Jatropha curcas L.seed oil

The preparation and regeneration conditions of the identified catalyst X/Y/MgO/?-Al2O3 with high catalytic activity were studied and optimized. The biodiesel was prepared by transesterification of Jatropha curcas seed oil produced in Guizhou with methanol at its reflux temoerature in the presence of X/Y/MgO/?-Al2O3 . The pilot plant tests were carried out in a 100 L reaction vessel. Both average yield and fatty acid methyl esters (FAME) content reached more than 96.50% under the optimum reaction conditions of the pilot plant tests designed with an oil/methanol molar ratio of 1 : 10, catalyst concentration of 1.00%, and reaction time of 3 h at reflux temperature. In addition, analysis shows that the quality of biodiesel meets the standard EN 14214.

Primary amine-functionalized mesoporous phenolic resin as an effective and stable solid base catalyst for Knoevenagel reactions in water

A primary amine functionalized ordered mesoporous phenolic resin(NH2-MPR)was obtained by an evaporationinduced self-assembly method.The as-prepared NH2-MPR material possessed large surface area and ordered twodimensional hexagonal mesoporous structure.Also,the amine groups were well-dispersed in the mesoporous channels.It can act as an efficient solid base to promote Knoevenagel condensation of various aldehydes with ethyl cyanoacetate in water with high conversion and selectivity.This excellent performance was attributed ordered mesopores and hydrophobic pore surface,which resulted in the decreased the interference of water solvent and the increased active sites accessibility.Noted that it was comparable with homogenous base catalysts in the water-medium Knoevenagel condensation reaction,and it can be reused for at least five times without significant reduction in the catalytic efficiency.

Acetalization of carbonyl compounds with 2,2,4-trimethyl-1,3-pentanedio catalyzed by novel carbon based solid acid catalyst

The synthesis of 2, 4-diisopropyl-5,5-dimethy1- 1.3-dioxane through the acetalization of isobutyraldehyde with 2, 2, 4-trimethy1-1,3-pentanediol （TMPD） catalyzed by the novel carbon based acid was first carried out. High conversion （≥98%） and specific selectivity were obtained using the novel carbon based acid, which kept high activity after it was reused 5 times. Moreover. the catalyst could be used to catalyze the acetalization and ketalization of different aldehydes and ketones with superior yield. The yield of several products was over 90%. The novel heterogeneous catalyst has the distinct advantages of high activity, strikingly simple workup procedure, non-pollution, and reusability, which will contribute to the success of the green process greatly.

Wet carbon-based solid acid/NaNO_3 as a mild and efficient reagent for nitration of aromatic compound under solvent free conditions

Nitro aromatic compound can be obtained in high yields via nitration of aromatic compound with wet carbon-based solid acid and NaNO_3 under solvent free oxidation at room temperature.

Wet carbon-based solid acid/potassium permanganate as an efficient heterogeneous reagents for oxidation of alcohols under mild conditions

Wet carbon-based solid acid and potassium permanganate were used as new reagents for oxidation of alcohols to their corresponding aldehydes and ketones in heterogeneous mixtures. The experiments were done moderately at mild condition and high yields in suitable times were obtained.

Effect of solid-solution temperature on the microstructure of Fe-Ni based high strength low thermal expansion (HSLTE) alloy

The influence of solid-solution temperature on the dissolution of carbide precipitates, the average grain size and the microhardness of the austenite matrix in an Fe-Ni based high strength low thermal expansion （HSLTE） alloy was investigated to obtain the proper temperature range of the solid-solution process. The XRD analysis, microstructure observations, and the theoretical calculations showed that the Mo-rich M2C-type precipitates in the Fe-Ni based HSLTE alloy dissolve completely at about 1100℃. The average grain size of the studied alloys increases from 14 to 46 μm in the temperature range of 1050 to 1200℃. The microhardness of the matrix decreases gust for the sake of solid-solution treatment, but then increases later with increasing solution temperature because of the solution strengthening effect.

The Development of Gear Pump CAD/CAPP Based on Solid Works

Nowadays, many kinds of software, which have succes sf ully created the integration of CAD, CAPP and CAM, find their disadvantages in p ractical manufacturing. As a result, it is welcomed to develop small CAD/CAPP sy stems on a proper CAD platform, which aim at requirements of factories. Based on the one of the most popular three-dimensional design software SolidWorks, we successfully developed a set of gear pump CAD /CAPP software for Huaiyin Gene ral Factory of Mechanics. 1 The architecture and function of the software According to the need of the enterprises, the general structure of the software contain two subsystems, which are detailed as follows: · The gear pump CAD subsystem contains four main modules, including the optiona l design module of gear pump, module of part design, the module of entity modeli ng and the module of drawing which creates 2 D drawings of parts and assembly c orresponding 3 D modals. · The gear pump CAPP subsystem, which is a combination of creative mode and der ivate mode, also includes four modules, they are the module of access to feature s, the module of planning process route, the module of designing process sheets and the module of generating process documents. 2 The developing environment of the system Basing on Windows 98 and SolidWorks2001 platform, this system creates all functi ons by using Visual C++ 6.0 as developing tools. 3 The keys to the CAD/CAPP integration 3.1 The establishment of product information modal The information of parts is the basis of process planning. In this system, we us e feature modeling to describe the information of parts and assembly of gear pum p, and set up a fundamental basis for the whole system. The information module o f gear pump includes the information of both the assembly and the parts; the par t-describing module uses four-layer structure that is subassembly layer, part layer, feature layer and geometric layer. 3.2 The operation of the information on feature modeling After establishment of information mode of gear pump, the next key problem is ho w to transmit information of product to CAPP subsystem. In order to integrate pe rfectly, connecting CAD with CAPP directly can be a good method. In this system, all information of parts is store in the part drawing files, and the CAPP syste m can load these files to get information. The gear pumps, which are produced by Huaiyin General Factory of Mechanics, are usually belong to several similar typ es, and this means that most products possess large number of similar feature. T herefore, we can easily establish a specific feature for gear pump CAD/CAPP syst em. All parts are created by selecting these features and/or adding few special features. In the module of access to feature of CAPP subsystem, the main task is to find the features and the information will be easily got. 4 Conclusion This system successfully creates gear pump CAD/CAPP integration based on SolidWo rks. 3D CAD software provide more convenient platform for integration and will i nevitably become the mainstream of product design. By developing this system, we clearly realize the promising future of SolidWorks.

Magnetic Field Measurement with Heisenberg Limit Based on Solid Spin NOON State

The maximum entangled number state （NOON state） can improve the sensitivity of physical quantity measure- ment to the Heisenberg limit 1/N. In this work, the magnetic field measurement based on the individual solid spin NOON state is investigated. Based on the tunable effective coupling coefficient, we propose a generation scheme of the three-spin NOON state, i.e, the Creenberger-Horne-Zeilinger （CHZ） state, and discussed the mea- surement resolution reduction due to decoherence. It is unnecessary to entangle spins as many as possible when decoherence exists. In practice, defect spins in diamond and alp donors with long coherence time can be applied with current techniques in the nano-scaled high resolution magnetic measurement.

High-Efficiency Generation of 0.12 mJ, 8.6 Fs Pulses at 400 nm Based on Spectral Broadening in Solid Thin Plates

We demonstrate eftlcient generation of continuous spectrum centered at 40Ohm from solid thin plates. By frequency doubling of 0.8m J, 3Ors Ti：sapphire laser pulses with a BBO crystal, 0.2m J, 33fs laser pulses at 400nm are generated. Focusing the 400-nm pulses into 7 thin fused silica plates, we obtain 0.15mJ continuous spectrum covering 350-450 nm. After compressing by 3 pairs of chirped mirrors, 0. 12 m J, 8.6 fs pulses are achieved. To the best of our knowledge, this is the first time that sub-10-fs pulses centered at 400nm are generated by solid thin plates, which shows that spectral broadening in solid-state materials works not only at 800nm but also at different wavelengths.

Abnormal mechanical property evolution induced by heat treatment for a semi-solid forming hypereutectic Al-Fe base alloy

In the present study, Al-5.5Fe-4Cu-2Zn-0.4Mg-0.5Mn al oy samples were prepared by electromagnetic stirring and semi-solid forming processing, and then the effects of T6 and T1 heat treatments on the microstructures and mechanical properties of the semi-solid forming samples were investigated. The results indicate that after semi-solid forming, the mechanical properties of the sample improved significantly compared to that of the merely electromagnetically stirred sample. The grains of semi-solid forming alloy became almost fine equiaxed; big long strip-shaped Al3 Fe phases became short rod-like morphology and distributed uniformly in the matrix. However, the mechanical properties of the T6-treated semi-solid forming sample decreased significantly instead of increasing and, with solution temperature rising, the tensile strength of the al oy decreased further. The results of EDS show that after high temperature solid-solution treatment, the Cu element in the semi-solid forming alloy sample is mainly concentrated at the boundaries of the Al3 Fe phases instead of being dissolved in the matrix. At the same time, the grains of the semi-solid forming sample grew slightly after solid-solution treatment. Therefore, the growth of the grains and the accumulation of Cu element at Al3 Fe phase boundaries during solution treatment of the semi-solid forming alloy were the main reasons for the mechanical properties decreasing after T6 treatment. The mechanical properties of the alloy were improved after T1 heat treatment due to aging strengthening phase being precipitated in the matrix.

Solid Solution Characteristics of Pb(B_(1/3)Nb_(2/3))O_(3)-based Composite Ceramics

The solid solution characteristics of Pb（B1/3Nb2/3）O3-based （B=Zn^2＋, Mg^2＋, Ni^2＋） composite ceramics prepared by two-phase mixed-sintering method were developed based on dielectric measurements. Results show that there are double dielectric peaks for PZN-based composite ceramic, implying two phases coexist. However single dielectric peak was presented in PMN- and PNN-based composite ceramics, respectively. It is indicated that obvious solid solution reaction exists during the sintering process of these two systems. The effects of B-site ion difference on the solid solution characteristics were discussed by crystal chemistry. SEM was employed to investigated the microstructures of composite ceramics. The influences of solid solution reaction on grain growth were discussed.