煤系高岭土原位晶化合成NaY分子筛的研究

我国煤系高岭土的储量丰富,被广泛应用于造纸、陶瓷、塑料、橡胶、电子、涂料、耐火材料以及石油化工等不同领域(张永明等,1997;郑淑琴等,2003;刘欣梅等,2002;郑淑琴等,2002)。高岭土在石油化工中主要用于炼油催化剂的制备,目前已有的用高岭土原位晶化合成NaY分子筛的报导中,利用煤系高岭土作为原料的并不多见。

低成本合成A型分子筛

以催化剂生产装置的工业原料为基础,考察了低成本制备高质量的4 A分子筛的晶化合成条件,以及经改性后所得5 A分子筛对石脑油组分的吸附-脱附性能。结果表明:优选出的4 A分子筛的较佳晶化制备条件为:n(Na_(2)O)/n(SiO_(2))为2.8~3.1,n(SiO_(2))/n(Al_(2)O_(3))为1.0~1.5,n(H2O)/n(Al2O3)为123.0~148.0,晶化温度为90~100℃,晶化时间为5 h以上;分别采用含不同SiO_(2)质量分数的硅源水玻璃、晶化母液1、晶化母液2,在较佳晶化制备条件下,均可合成出相对结晶度大于80%的4 A分子筛;经改性所得5 A分子筛对正己烷的吸附-脱附性能优于工业市售品HZSM-5分子筛的。

酸处理红辉沸石-碱-铝酸钠-水的水热反应体系中A型沸石的合成

以酸处理红辉沸石为原料 ,采用水热反应晶化合成工艺 ,合成出了质量较高的 4A沸石产品 .在大量实验基础上 ,利用X射线衍射分析、扫描电镜观察等系统地研究了反应混合物的钠硅比 [n(Na2 O) /n(SiO2 ) ]和水钠比 [n(H2 O) /n(Na2 O) ] ,以及晶化时间和晶化温度对酸处理红辉沸石 -碱 -铝酸钠 -水的水热反应体系中A型沸石晶化合成的影响 .确定了最佳工艺技术参数 :硅铝比 [n(SiO2 ) /n(Al2 O3) ]为 2 ,钠硅比 [n(Na2 O) /n(SiO2 ) ]为 1.1,水钠比 [n(H2 O) /n(Na2 O) ]为 45 ,晶化时间大于 6h ,晶化温度为 10

粉煤灰分子筛的合成方法及其研究进展

简述了分子筛的基本结构、类型、用途以及合成原料等。对粉煤灰合成分子筛过程中的各种预处理方法和晶化合成方法及其优缺点进行了详细描述,其中,使用最广泛的预处理方法为酸处理法,合成方法中使用最为广泛的为水热合成法,并根据相关研究成果,对酸预处理和水热合成法的改进提出了展望。

SAPO-34分子筛合成的研究进展

综述了SAPO-34分子筛合成方法的研究进展,并从原料、晶化时间、晶化温度、硅铝比和模板剂等角度,重点介绍了SAPO-34分子筛水热合成中的影响因素;最后针对目前广泛讨论的环境污染问题,指出需加大对SAPO-34分子筛晶化母液的循环利用,提高原料利用率、降低生产成本、减少污水排放量。

Facile synthesis of tin oxide nanocrystals and their photocatalytic activity

Tin oxide nanociystals with diameters smaller than 10 nm were synthesized using Na2SnO3 and CO2 as reactants and cetyltrimethylammonium bromide（CTAB） as stabilizer under mild conditions.As a mild acidic gas,CO2 is favorable for the accurate adjustment of pH value of Na2SnO3 solution.Stannate salt is stable,cheap and easy in operation.The effects of Na2SnO3concentration,CTAB concentration,aging temperature,and aging time on the nanociystals were studied.It was found that,with the increasing Na2SnO3 concentration,aging temperature and aging time,SnO2 nanociystals size decreases.The formation of SnO2nanociystals can be interpreted by electrostatic-interaction mechanism.SnO2 nanociystals show high photocatalytic activities in the degradation of Rhodamine B solution.The catalytic activity of small nanocrystals is higher than that of large ones.

Seed-induced synthesis of small-crystal TS-1 using ammonia as alkali source

Small-crystal TS-1 was synthesized via a seed-induced approach using ammonia as the alkali source and tetrapropylammonium bromide as an auxiliary structure-directing agent. The TS-1 samples were characterized using X-ray diffraction, N2 adsorption-desorption, Fourier-transform infrared spectroscopy, inductively coupled plasma atomic emission spectroscopy, scanning electron microscopy, and ultraviolet-visible spectroscopy. The use of the colloidal seed reduced the crystal size, and an appropriate amount of silicalite-1 seed assisted Ti incorporation into the TS-1 framework. This method reduces the cost of TS- 1 synthesis because a significantly smaller amount of tetrapropylammonium hydroxide is used. The catalytic performance of the synthesized small-crystal TS-1 samples in cyclohexanone ammoximation was better than that of bulk TS-1 as a result of improved diffusion and a larger number of active tetrahedral Ti centers.

Amorphous nanomaterials in electrocatalytic water splitting

Electrochemical water splitting,as a promising method for hydrogen production,has attracted significant attention.However,the lack of an electrocatalyst with a small energy loss and fast reaction kinetics has hindered the development of this technology.Amorphous nanomaterials with short-range order and long-range disorder features have recently shown superior activity compared to their crystalline counterparts in water electrolysis.The enhanced activity arising from their intrinsic disordered structure results in more active sites and a higher intrinsic activity of such sites.In this regard,this review is aimed at summarizing the progress in amorphous electrocatalysts for water splitting.First,the synthesis strategies for amorphous electrocatalysts are discussed.Characterization tools for amorphous nanomaterials are then summarized.Moreover,the origin of the enhanced activity and stability of amorphous nanomaterials is analyzed.Finally,the current challenges and promising opportunities in this research area are discussed.This review aims to provide a guide for designing and developing amorphous nanomaterials with a fascinating electrocatalytic water splitting performance.

Synthesis of ZnO whiskers via hydrothermal decomposition route

ZnO whiskers with a length of 30-40μm and a diameter of about 1μm were synthesized by co-precipitation of ZnSO 4 and Na2CO3 solution at room temperature followed by hydrothermal treatment of the as-prepared Zn5(CO3)2(OH)6 precursor at 160 ℃for 6 h.The increase of the initial solution pH promotes the hydrothermal conversion of the particulate Zn5(CO3)2(OH)6 to ZnO whiskers.The presence of minor amount of EDTA in the hydrothermal solution promotes the one dimensional growth of ZnO whiskers,leading to the formation of ZnO whiskers with a length of 50-60μm and a diameter of 1-2μm.

Synthesis and Structure of Copper(Ⅱ) Complex [Cu(C_5H_5N)_2(H_2O)(C_6H_5COO)_2]

At room temperature, the reaction of dibenzoyl peroxide with metallic copper powder in the presence of pyridine affords the copper(Ⅱ) complex [Cu(C 5H 5N) 2(H 2O)\|(C 6H 5COO) 2]. Crystal is monoclinic, M r =483.002, space group Cc with parameters: a=6\^078(4), b=15.879(4), c=23.091(3), β=97.61(2)°, V=2209.1(2) 3, Z=4, D c =1\^464g/cm 3, μ =10.279 cm -1 , F(000)=996, R=0\^031, R w =0.036, 1595 reflections with I≥3σ(I ) were considered to be observed. Each copper(Ⅱ) ion is coordinated by two monodentate benzoate ligands, two pyridines and one water molecule. The complex is also characterized by its IR, XPS and thermal properties.

Hydrothermal synthesis and electrochemical sensing properties of copper vanadate nanocrystals with controlled morphologies

Morphology-controlled synthesis of copper vanadate nanocrystals is of great significance in electrochemical sensing applications.A facile hydrothermal process for synthesizing copper vanadate nanocrystals with various morphologies(e.g.,nanoparticles,nanobelts and nanoflowers)was reported.Phase,morphology and electrochemical performance of the as-synthesized copper vanadate nanocrystals were characterized by X-ray diffraction(XRD),scanning electron microscope(SEM)and cyclic-voltammogram(CV)techniques.The results revealed that the morphologies of the Cu3V2O7(OH)2·2H2O(CVOH)nanocrystals could be controlled by changing copper salts,surfactants and pH values.The CVOH samples showed enhanced electrochemical response to ascorbic acid.Comparatively,the CVOH nanobelts had the higher electrochemical sensing performance than those of CVOH nanoparticles and nanoflowers.The CVOH-nanobelts-modified GCEs had a linear relationship between the peak currents in their CVs and ascorbic acid concentration.The CVOH nanocrystals can be used as potential electrochemical active materials for the determination of ascorbic acid.

Synthesis of ZSM-5/MOR Co-crystalline Zeolite without Template and the Catalytic Application Thereof

A ZSM-5/MOR co-crystalline zeolite was synthesized without using the template. The physico-chemical properties of the zeolite were characterized by XRD, FT-IR, SEM and TPD and then compared with the co-crystalline zeolite synthesized with a template. Analytical results indicated that they were similar in structure and composition. The influences ofpH value and Si/Al ratio on synthesis were studied. It was found that a high pH value or a low Si/AI ratio could provide better environment for mordenite （MOR） crystallization. The zeolites applied as catalysts in naphtha catalytic cracking for producing ethylene and propylene showed outstanding catalytic performance with the total yield of ethylene and propylene reaching 55 m%. The process could achieve most favorable efficiency when the catalyst contained 5 m% of MOR.

Synthesis and Crystal Structure of O,O-Dimethyl-N-(β-triphenylgermanyl)propionyl-α- aminobenzylphosphonates

The title compound (C30H32NO4PGe), O,O-dimethyl-N-(β-triphenylgermanyl) propionyl-α-aminobenzylphosphonates was synthesized by a convenient method, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal is triclinic, space group P-1 with parameters: a=9.7753(5), b=11.5773(5), c=13.5059(6) ?, α=104.185(1),β= 95.971(1), γ =96.727(1)°, V=1457.63(12) ?3, Z=2, Mr=574.13, Dc=1.308 g/cm3, λ=0.71073 ?, μ = 1.139mm-1, and F(000)=596. The structure was solved by direct methods. The structure was refined to R=0.0257, wR=0.0705 for 5080 observed reflections with I >2σ(I).The result of structure analysis indicates that atom Ge is sp3 hydridized because the arrangement of the four carbon atoms bonded to it is a distorted tetrahedron. The geometry of the three phenyl groups linking with the Ge atom looks like a propeller form.

Synthesis and Crystal Structure of Methyl(7,7-Dimethyl-2-amino-4-(4-chlorophenyl)-5-oxo-5,6,7,8-tetrahydro-4H-benzo-[b]-pyran-3-yl)Carboxylate

The title compound methyl (7,7-dimemyl-2-amino-4-(4-chlorophenyl)-5-oxo-5,6,7,8-tetrahydro-4H-benzo-[b]-pyran-3-yl) carboxylate (C19H20ClNO4, Mr = 361.81) was synthesized and crystallized. The crystal belongs to triclinic, space group P 1 with a = 8.519(2), b = 10.346(2), c = 11.481(3) A, α = 108.16(1), β = 107.78(2), γ= 91.83(2)°, Z = 2, V = 906.5(3) A3, Dc = 1.326 g/cm3, μ(MoKα) = 0.234 mm-1, F(000) = 380, R = 0.0467 and wR = 0.1270 for 3142 observed reflections (I > 2σ(I)). X-ray analysis reveals that the C(7), C(8), C(9), O(1), C(10) and C(11) atoms form a six-membered ring which adopts a boat conformation. In the ring, the distances of C(8)-C(9) and C(10)-C(11) are 1.332(3) and 1.357(3) A, respectively, which indicates that they are C=C double bonds. Another six-membered ring (C(8)-C(9)-C(15)-C(14)-C(13)-C(12)) adopts the half-chair confonnation. In addition, there are intermolecular hydrogen bonds in the crystal structure.

Thermodynamics, kinetics and mechanism analysis of Cu(Ⅱ) adsorption by in-situ synthesized struvite crystal

Synthesized struvite was innovatively applied to removing Cu（II） from aqueous solution. The Cu（II） adsorption behavior and relative mechanisms were studied and analyzed. The maximum Cu（II） adsorption under pH=4.0 and 318 K calculated from adsorption thermodynamic analysis was 145.1 mg/g. The sorption kinetics can be favorably described by pseudo-second order model. The activation energy （Ea） of 17.5 kJ/mol suggested that the adsorption process was a chemical adsorption. The calculated thermodynamic parameters indicated that the adsorption was a spontaneous and endothermic one. On the basis of characterization upon struvite before and after adsorption, it was found that the electrostatic attraction and coordination bonding supported the ion sorption on struvite surface, and the transformation of copper ion into copper hydroxide occurred on struvite surface and within its crevices.

Synthesis and Crystal Structure of (1,3-~tBu_2C_5H_3)_2Sm( μ-Cl)_2Li(THF)_2

Anhydrous SmCl 3 reacts with two equal of Li(1,3 tBu 2C 5H 3) to give a complex (1,3 tBu 2C 5H 3) 2Sm( μ Cl) 2Li(THF) 2(C 34 H 58 Cl 2LiO 2Sm, M r =726.99), monoclinic, space group P2 1/n, a=10.615(2), b=21.037(4), c=17.166(3), β=93.60(3)°, V=3825\^7(13) 3, Z=4, D c =1.262Mg/m 3, μ =1.699mm -1 and F (000)=1508, final R= 0.0387 and wR =0.0741 for 5320 observed[ I2σ(I)] reflections. The average Sm-C distance is 2\^73. Sm-Cl1 and Sm-Cl2 distances are 2\^719(2) and 2.697(2), respectively. Two 1,3 tBu 2C 5H 3 ring centroids and two μ 2 bridging chloride atoms around Sm atom form a distorted tetrahedron.

Solvothermal synthesis and characterization of nanocrystalline vanadium-chromium composite oxides and catalytic ammoxidation of 2,6-dichlorotoluene

Vanadium‐chromium oxides(VCrO)were usually prepared by high‐temperature solid‐state reactions;however,mixed phases were frequently produced and the morphology of the products was not well controlled.In this work,we prepared amorphous VCrO precursors by using V2O5 and CrO3 and alcohols or mixtures of alcohol and water via solvothermal reaction at 180°C.The precursors were then calcined under nitrogen at various temperatures.The products were characterized by powder X‐ray diffraction,transmission electron microscopy,and X‐ray photoelectron spectroscopy.It was revealed that pure‐phase nanocrystalline orthorhombic CrVO4 was obtained when methanol or methanol/water was used as the solvothermal medium and the precursor was calcined at 700°C.The size of the CrVO4 crystals was around 500 nm when methanol was used,whereas it reduced significantly to less than 50 nm when a mixture of methanol and water was used.The sizes could be effectively tuned from 10 to 50 nm by varying the methanol/water volume ratio.To the best of our knowledge,this is the first report on the synthesis of pure‐phase CrVO4 nanocrystals.The nano‐CrVO4 showed almost the highest catalytic activity for the ammoxidation of 2,6‐dichlorotoluene to 2,6‐dichlorobenzonitrile among the reported bi‐component composite oxides,owing to its smaller particle size,larger specific surface area,and more exposed active centers.

Formation kinetics and transition mechanism of CaO·SiO2 in low-calcium system during high-temperature sintering

The crystal structure,formation kinetics and micro-morphology of CaO·SiO2 during high-temperature sintering process were studied in low-calcium system by XRD,FT-IR,Raman and SEM-EDS methods.When the molar ratio of CaCO3 to SiO2 is 1.0,β-2CaO·SiO2 forms firstly during the heating process,and then CaO·SiO2 is generated by the transformation reaction of pre-formed 2CaO·SiO2 with SiO2.3CaO·SiO2 and 3CaO·2SiO2 do not form either in the heating or sintering process.Rising the sintering temperature and prolonging the holding time promote the phase transition of 2CaO·SiO2 to CaO·SiO2,resulting in the sintered products a small blue shift and broadening in Raman spectra.The content of CS can reach 97.4%when sintered at 1400℃ for 1 h.The formation kinetics of CaO·SiO2 follows the second-order chemical reaction model,and the corresponding apparent activation energy and pre-exponential factor are 505.82 kJ/mol and 2.16×10^14 s^−1 respectively.

π-π Stacking Force in the Solid Structure of Mixed-Metal Complexes: Zn(phen)_2MS_4 (M=W, Mo)

The inter-diffusion of N,N-dimethylformamide solution of Zn(phen)2Cl2 and (NH4)2MS4 (M = W, Mo) in an H-shape tube produced crystals of Zn(phen)2WS4 1 and Zn(phen)2MoS4 2 (phen = 1,10-phenanthroline). The structures of isomorphous complexes 1 and 2 have been determined by X-ray single-crystal structure analyses. Four nitrogen atoms from the phenanthroline ligands and two sulfur atoms from the MS42- anion forming a distorted octahedron coordinate each zinc atom. Through p-p interactions of adjacent aromatic rings of the phenanthroline ligands, a quasi one-dimensional zigzag-stacking column is formed in each complex. Complex 1 crystallizes in monoclinic space group C2/c, with a = 10.447(8), b = 22.016(9), c = 12.824(8) ? b = 103.56(6)? V = 2867.7(8) 3, Z = 4, C24H16N4S4WZn, Mr=737.90, Dc = 1.71 g/cm3, F(000) = 1424, m = 5.25 mm-1, the final R = 0.054 and Rw = 0.075 for 2315 observations with I > 3s (I). Complex 2 crystallizes in monoclinic space group C2/c, with a = 10.410(6), b = 22.095(7), c = 12.830(6) ? b = 103.19(8)? V = 2873.1(5) 3, Z = 4, C24H16MoN4S4Zn, Mr=649.99, Dc = 1.50 g/cm3, F(000) = 1296, m = 1.58 mm-1, the final R = 0.072 and Rw = 0.100 for 1631 observations with I > 3s(I).

Synthesis and Crystal Structure of Pd(AETYF)Cl_2CH_2Cl_2 [AETYF = 4'5'Diaza-9' (4,5-bis(ethylthio)-1,3-dithiole-2-ylidene)-fluorene]

A stable Pd(II) compound Pd(AETYF)Cl2CH2Cl2 (AETYF = 4?5?diaza-9? (4,5-bis(ethylthio)-1,3-dithiole-2-ylidene)-fluorene) has been synthesized and its crystal structure was determined by X-ray crystallography. The crystal is of monoclinic, space group P21/c with a = 15.249(6), b = 8.619(3), c = 19.078(7) ? b = 106.932(8), C19H18Cl4N2PdS4, Mr = 650.79, V = 2398.6(16) 3, Z = 4, Dc = 1.802 g/cm3, F(000) = 1296, m = 1.579 mm-1, Npar = 268, the final R = 0.0538 and wR = 0.1282 for 5068 observed reflections with I > 2s(I). The crystal structure determi- nation shows that the atoms of the molecule, except two ethyl-groups, are conjugated in a quasi- plane and these molecules are further stacked or contacted via plane to plane or edge to edge p-p interactions, forming parallel molecular chains along the b axis.