Hydrothermal synthesis of AlPO4-5 type zeolitic materials by using aluminum dross as a raw material

The hydrothermal synthesis of AIPO₄-5, which is one of the large pore size aluminum phosphate condensates like zeolitic materials, was carried out by using aluminum dross as a raw material. Triethylamine (TEA) was used as a structure directing agent (SDA) for AIPO₄-5 synthesis. Various physical properties such as crystal structure, surface texture and specific surface area were investigated for the obtained reaction product.AlPO₄-5 can be synthesized from aluminum dross under hydrothermal conditions at 453–473 K for 3 h. AlPO₄ salt as a by-product, which is a non-porous material, is formed at the same time. The crystal of the obtained AlPO₄-5 is hexagonal as observed by SEM photographs. It is desirable to heat-treat the reaction product at the temperature around 823 K to remove TEA. The crystal structure of AlPO₄-5 changes to non-porous aluminum phosphate in case of a heat treatment exceeding 973 K. The specific surface areas of the reaction product before and after heat treatment at 823 K are 18 and 360 m²/g, respectively.     

Organic-free VPI-5: Synthesis and characterization of AlPO4-H1

The aluminophosphate H1 first reported by D'Yvoire in 1961 has been prepared in highly crystalline pure form from a reactive gel system without aging in the absence of an organic additive. Potential seeding in this system was avoided by using new crystallization vessels. Its physical and thermal properties are identical to that of VPI-5. These results indicate that VPI-5 does not represent a new microporous phase but rather H1 prepared in the presence of organic additives.     

AlPO4-5分子筛大晶体的合成

研究了阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)对水热晶化法合成AlPO4-5大晶体的影响.实验过程中以拟薄水铝石为铝源,正磷酸为磷源,三正丙胺为模板剂,在晶化原液中添加一定量的氢氟酸、异丙醇以及CTAB.通过改变CTAB的添加量,在晶化温度180℃,晶化时间24.0 h的条件下,合成出了大而完美的六角棱柱形的AlPO4-5晶体,晶体尺寸可达890 μm×120 μm.实验结果表明,晶体的大小及完美程度与表面活性剂中烷基三甲基铵阳离子与晶化液中的负电荷基团[AlF6]3-和[PF6]1-的吸附作用有关.     

纯相BiFeO_3微晶的水热合成及表征

以Bi(NO3)3.5H2O和Fe(NO3)3.9H2O为原料,KOH为矿化剂,聚乙二醇6000为分散剂,水热合成BiFeO3粉体,XRD和Raman光谱对粉体的表征说明在200℃反应6 h可以得到纯净的单相BiFeO3粉体,热分析结果得到BiFeO3粉体的磁相变温度——尼尔温度(TN)和铁电相变温度——居里温度(Tc)。     

Sr,Mg co-doping of calcium hydroxyapatite: Hydrothermal synthesis,processing, characterization and possible application as dentin substitutes

The aim of this study was to investigate the influence of binary Sr, Mg ion-doping compared to the single-ion doping effects on the phase composition and morphology of hydrothermally obtained calcium hydroxyapatite (HAP) powders and on the phase composition, microstructure, and mechanical properties of the sintered materials. Additionally, the focus of this study was to investigate the possible utilization of the binary doped Sr,Mg-HAP compacts as dentin substitutes in restorative dentistry by evaluating their bonding ability with commercially available restorative materials using the shear bond strength test (SBS). The hydrothermally obtained mono-doped Mg5 and Sr5 showed the monophasic apatite structure, while in all co-doped samples β-TCP phase was formed, resulting in biphasic calcium phosphate (BCP) powders. It was confirmed that co-doping with Sr and Mg ions led to the thermal stabilization of the β-TCP phase by suppressing the phase transition into α-TCP when sintered at 1200 °C. Moreover, the co-presence of Mg ions significantly improved the hardness of Sr-doped HAP from 3.74 to 5.02 GPa. Sr,Mg-HAP dental inserts were found to achieve sufficient bonding (13.53 MPa) through the micromechanical interlocking with Z250 dental composite and Single Bond Universal dental adhesive applied with a total etch approach. The SBS values obtained for the SrMg-HAP insert were similar to the literature data on bonding ability with human dentin, indicating that binary doped Sr,Mg-HAP ceramics present a promising material for application in restorative dentistry as dentin substitutes.     

Characterization of the amorphous phases formed during the synthesis of microporous material AlPO4-5

We have used several solid-state NMR techniques in conjunction with powder X-ray diffraction (XRD) and Raman spectroscopy to characterize the structure of the intermediate amorphous phases of AlPO₄-5 molecular sieve synthesis. The evolution of the gel phases as a function of crystallization time was followed by ³¹P and ²⁷Al magic-angle spinning (MAS) NMR to obtain information on the local environments of Al and P atoms and by powder XRD to detect the long-range ordering of the gel samples. We have utilized ²⁷Al/³¹P double-resonance techniques such as heteronuclear correlation spectroscopy (HETCOR) to select the ³¹P–O–²⁷Al bonding connectivities and transfer of populations by double-resonance (TRAPDOR) to obtain information regarding the degree of condensation for P sites in the amorphous phases. The ¹H → ³¹P cross-polarization (CP) was used to identify the P sites with hydroxyl groups attached. Raman spectroscopy was also employed to follow the evaluation of the pore system. The ¹³C CP MAS spectra provide information regarding the chemical environment of template molecule in the gel. The work shows that a combination of the above-mentioned techniques can provide more detailed information on the structure of amorphous phases formed during hydrothermal synthesis.     

Towards Rational Synthesis of Microporous Aluminophosphate AlPO4-21 by Hydrothermal Combinatorial Approach

We present a strategy toward the rational synthesis of microporous materials by combination of computational and combinatorial approach. In terms of nonbonding interaction energies of host–guest calculated by the molecular dynamics simulations using Cerius²package, the templating abilities of various organic amines in the formation of microporous aluminophosphate AlPO₄-21 have been evaluated. Through rational selection of the predicted suitable templates, such as ethanolamine, trimethylamine and N, N, N′, N′-tetramethylenediamine, AlPO₄-21 has been successfully synthesized by hydrothermal combinatorial approaches in the reaction system 1.0Al(ⁱOPr)₃-xH₃PO₄-yR-255.0H₂O (R amines). The as-synthesized products are characterized by automated X-ray powder diffraction, ICP, TG, and single-crystal X-ray diffraction analyses. Their framework structures belong to zeotype AWO, which possesses eight-membered ring channels along [001] direction.     

AlPO4-5担载溴化铝催化酮的Baeyer-Villiger氧化

以异丙醇铝为铝源,正磷酸为磷源,三乙胺作模板剂, 采用水热反应合成了AlPO4-5分子筛。应用不同浓度氢溴酸对AlPO4-5分子筛进行化学剪裁,制备AlPO4-5-AlBr3催化剂。FESEM、XRD、N2吸附-脱附等表征表明,合成的AlPO4-5是规整的微孔六方棱柱,化学剪裁制备的担载型催化剂AlPO4-5-AlBr3依然保持规整的六方棱柱。催化氧化实验表明,30%双氧水作为氧化剂,在乙酸乙酯溶剂中,催化剂AlPO4-5-AlBr3对部分环酮具有较好的催化活性,催化剂能够循环利用多次。     

Hydrothermal synthesis,magnetic properties and characterization of CoFe2O4 nanocrystals

Magnetic cobalt ferrite (CoFe₂O₄) nanocrystals were synthesized via the hydrothermal method and the crystallite size was measured using Sherrer's equation. Instrumental broadening was a significant parameter for determining crystallite size. The effect of annealing time and calcination on crystallite size and magnetic properties was discussed. It was found that the coercivity was highly dependent on the crystallite size. As the crystallite size increased from 61 to 68.2 nm, room temperature coercivity increased from 1488 Oe to 1700 Oe, while high coercivity (5.2 kOe) was achieved at lower temperature (80 K). It was found that the presence of hematite could affect the crystallite size after calcination.     

Characteristics of Fe/AlPO4-5 catalyst prepared with organic solution

The Fe/AlPO₄-5 catalysts are prepared by impregnation with aqueous and organic solution (acetic acid, alcohol and acetone) of iron(III) nitrite respectively. The characterization of catalyst by means of XPS, Mössbauer spectroscopy, TPR and CO hydrogenation is reported. The catalyst prepared with the aqueous solution has no activity for CO hydrogenation because the Fe(III) in the catalyst cannot be reduced to -Fe. However, the catalysts prepared with organic solution possess obvious hydrogenation activity, in which -Fe is present in the initial reduced catalyst besides Fe³⁺ and Fe²⁺. The results may be explained by the interaction degrees between the metal and the support induced by the different impregnation solvents.     

The synthesis of some 5-arylazo-2,4,6- trichloropyrimidines and 4-arylamino-5-arylazo-2,6- dichloropyrimidines and their application as disperse reacti

Diazotised arylamines were coupled with barbituric acid to give 5-arylazo-6-hydroxypyrimidine-2,4-diones which were then refluxed with phosphorus oxychloride to give 5-arylazo-2,4,6-trichloropyrimidine dyes. The condensation of some of these with arylamines at low temperature gave 4-arylamino-5-arylazo-2, 6-dichloropyrimidine dyes. The dyes were applied to polyamide fibres as disperse reactive dyes and their fastness properties studied.     

Transparent and anti-fogging AlPO4-5 films constructed by oblique oriented nano-flake crystals

In the present work, transparent and anti-fogging AlPO₄-5 films were prepared on glass substrates using a novel developed process. The process entails a simple in-situ sol–gel followed by vapor phase transport. The in-situ sol–gel process was implemented by coating the precursor sols for the synthesis of AlPO₄-5 on the glass substrates successively using the spin-coating method. The films and powders scribed from the films were characterized by X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), atomic force microscope (AFM), X-ray photoelectron spectroscopy and transmission electron microscope (TEM). The unique films were composed of oblique oriented nano-flake AlPO₄-5 crystals with the thickness of about 20 nm. The formation of nano-flake crystals can be ascribed to the high concentration of the precursors, resulting in the formation of a supersaturation system. The obtained films showed high antifogging performance due to the superhydrophilicity with a water contact angle of lower than 1.0°. The silicone oil contact angle was also low about 8.2°. In addition, heteroatom-substituted AlPO₄-5 films showing different colors can be obtained easily by simply adding transition metal ions in the phosphate acid solution during the preparation that can extend the application of the method for different coating demand.     

Hydrothermal synthesis, characterization and structure refinement of chlorate- and perchlorate-sodalite

Chlorate- and perchlorate-sodalites were synthesized hydrothermally in the temperature range of 160°C to 500°C. IR absorption bands indicate the enclathration of NaClO₃ (624 cm⁻¹) and NaClO₄ (624 cm⁻¹ and 2050 cm⁻¹) in the sodalite cages. The thermal decomposition has been characterized by simultaneous thermal analysis (TG, DTG, DTA) and high temperature X-ray powder diffraction. The total collapse of the sodalite framework structure and the formation of nepheline could be observed at 750°C and 1100°C for chlorate-sodalite and perchlorate-sodalite, respectively.

The crystal structure has been determined for NaClO₄-sodalite showing cubic symmetry (a₀=9.071 Å, SG P 3n) and complete ordering of Si and Al in the silicate framework; the Si-O-Al angle is 146.7°. The Cl atoms of the enclathrated perchlorate are located at the central positions of the sodalite cages. For the oxygen atoms of the Cl₄⁻ anions the structure refinement led to orientationally disordered sites having a close resemblance to the well-known O(2) positions of basic sodalite Na₈[AlSiO₄]₆(OH)₂·2 H₂O.     

Hydrothermal synthesis of Ba5Nb4O15 ultrafine powders

Ba₅Nb₄O₁₅ ultrafine powders were prepared by hydrothermal method using Ba(NO₃)₂ and Nb₂O₅ precursors. The synthesis characteristics were influenced by the chemical form of precursors, reaction temperature, mole ratio of Ba/Nb and pH value. The chemical form of the precursors has a strong influence on the products of Ba₅Nb₄O₁₅. There was no requisite compound in the final product when Nb₂O₅ powder was used as Nb-precursor. In addition, the reaction completeness was also dependent on the synthesis temperature. The best single phase Ba₅Nb₄O₁₅ ultrafine powders were obtained at a temperature of 230 °C. The most appreciate Ba/Nb molar ratio was 3/2. The reactions were only carried out in a solution with pH value between 12 and 14. When pH was equal or larger than 14, there was no product of Ba₅Nb₄O₁₅ powder in the reactor.     

Flame synthesis of carbon nanofibers on carbon paper: Physicochemical characterization and application as catalyst support for methanol oxidation

We developed a simple, rapid and highly efficient flame synthesis method for direct growing carbon nanofibers (CNFs) on carbon paper (CP) using a common laboratory ethanol flame as both heat and carbon sources. High density CNFs with tangled solid-cored structure were uniformly formed over the Ni-plated CP surface in ∼20 s. The morphologies of the CNFs were characterized by scanning electron microscopy and transmission electron microscopy. X-ray diffraction study revealed the graphitic nature of the CNFs. Raman spectroscopy analysis confirmed that the CNFs are disordered graphitic nanocrystallites with high degree of exposed edges. Electrochemical impedance spectroscopy and cyclic voltammetry were used to show that growing CNFs directly on CP facilitates electron transfer with concomitant increase in double-layer capacitance. The CNF/CP was used as support for Pt nanoparticles to study their supporting effect on the catalyst performance. The as prepared Pt/CNF electrocatalyst exhibited much improved electrocatalytic activity for methanol oxidation compared to Pt/CP and commercial Pt/C on CP. High electronic conductivity and improved electrochemical behavior of the CNF/CPs, resulted from direct contact of the nanofibers with CP, combined with unique properties of CNFs, make the synthesized CNF/CPs promising for fuel cell applications.     

超增溶自组装法合成纳米AlPO_4-5分子筛

采用超增溶自组装法合成纳米级AlPO4-5分子筛,考察了焙烧温度、乳化剂质量分数对分子筛粒径及其分布的影响,结果表明在超增溶纳米自组装的条件下能够合成出类球形的纳米磷铝分子筛,并且通过调节乳化剂的质量分数可以控制纳米分子筛的粒径大小,纳米磷铝分子筛直径为10~80 nm,长度为0.1~0.2μm。     

新荧光试剂5－（4＇－硝基－2＇－羧基苯基偶氮）－2－硫代－4－噻唑啉酮的合成及其应用研究

报道了５－（４＇－硝基－２＇－羧基苯基偶氮）－２－硫代－４－噻唑啉酮（４ＮＲＡＣＰ）的合成。经柱层析提纯，用元素分析、ＩＲ、１ＨＮＭＲ和ＭＳ确证了其结构，研究了荧光性质，发现该试剂在溴代十六烷吡啶存在下，在无水乙醇溶液中与Ｅｕ（Ⅲ）形成稳定的荧光螯合物，λｅｘ／λｅｍ＝２９０ｎｍ／３４０ｎｍ，其线性范围为１．０×１０－８～１．０×１０－６ｍｏｌ·Ｌ－１，检测限为１．５×１０－１０ｍｏｌ·Ｌ－１。测定了人工合成样品中的铕，结果满意。     

(-)-1R,2S,5R-8-(4-溴苯)薄荷醇的合成与表征

以R-( )-长叶薄荷酮为起始原料,经1,4-加成、还原、溴代、水解等4步反应合成了标题化合物,总产率77%。其结构用1HNMR、13CNMR和IR进行了表征。     

介孔TiO2的水热法制备及表征

以廉价的工业级偏钛酸为原料,采用水热法制备了锐钛矿型介孔TiO2,考察了水热温度和水热时间对TiO2晶粒度的影响,并对TiO2进行了N2吸附-脱附、SEM及TG-DTA表征,结果表明,水热温度对TiO2晶粒度的影响较大而水热时间影响较小,纳米尺寸的TiO2晶体在聚乙二醇模板剂的作用下组装为微米级的介孔TiO2,平均介孔...     

硼酸镁晶须的水热合成及表征

以六水氯化镁和硼砂为原料,利用水热前躯体法在190℃水热10 h制备出长径比为30~90的碱式硼酸镁晶须,再将碱式硼酸镁晶须通过700℃高温焙烧3 h实现结构重整和物相转化,得到长径比为50~80、尺寸均一的硼酸镁晶须。利用X射线衍射(XRD)、扫描电镜(SEM)、热重分析(TG)等手段对碱式硼酸镁和硼酸镁的组成和形貌进行了表征。同时考察了反应物浓度、水热温度、水热时间及表面活性剂对前驱体形貌的影响。