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1.
就大一学生对[Cu(en)3]^2+是否发生Jahn-Teller畸变的作答情况,引发的关于规律的总结、知识的连续性、阶段性及教材处理方面的思考。  相似文献   

2.
Four pillared bentonites (Cr-PILB, Cr(acac)3-PILB, Fe-PILB and Fe(acac)3-PILB were prepared and characterized by X-ray diffraction (XRD), nitrogen sorption measurements and thermogravimetric (TG) analysis. The surface acidities of the samples and their structures were also investigated in the gas phase adsorption data of pyridine by the aid of FT-IR spectroscopic techniques. The XRD data and FT-IR spectra of the samples reflected mainly the structure of bentonite. The nitrogen adsorption–desorption isotherms of the samples were Type II shaped and showed in general mesoporous structures with pore openings of 4 nm. Two steps mass losses were observed in the TGA thermograms of B, Cr-PILB and Fe-PILB, while three steps mass losses were detected in the case of Cr(acac)3-PILB and Fe(acac)3-PILB. IR study by the adsorption of pyridine on the samples showed both Lewis and Brönsted acid sites on their surfaces.  相似文献   

3.
研究了K4[Fe(CN)6]掺杂剂对溴碘化银颗粒乳剂感光性能的影响,结果表明掺杂剂的掺杂量、掺杂位置以及在乳剂颗粒内部的分布区域对乳剂的感光性能都有影响。掺杂位置接近表面或接近内核时效果明显,掺杂位置接近富碘区域时,乳剂的感光度上升的不明显,较佳的掺杂量为1×10-6mol/molAgNO3。  相似文献   

4.
Layered double hydroxides (LDHs) containing Mg2+ and Al3+ in the basic layers and NO3 as an interlayer anion were synthesized by the method of coprecipitation (pH 10). By changing the Mg2+/Al3+ ratio (1.5–4.5), the charge density on the (NO3)–MgAl–LDH sheets was varied. After pillaring with Fe(CN)3−6, which was based on an anion exchange process, the interlayer space became accessible. This was reflected in the large created surface areas and micropore volumes. The applied models for the calculation of the micropore size distributions (Maes–Zhu–Vansant and Horvath–Kawazoe) gave matching results, revealing narrow distributions for all the samples, with the majority of the pores smaller than 0.71 nm. A correlation was found between the Mg2+/Al3+ ratio and the resulting microporosity after pillaring. The optimal ratio was situated around 3.3, resulting in a pillared [Fe(CN)6]–MgAl–LDH with a Langmuir surface area of 499 m2/g and a micropore volume between 0.158 ml/g (μPVmin) and 0.177 ml/g (μPVmax). As an alternative, direct coprecipitation of the pillared LDHs was evaluated. This one-step mechanism proved to be a method producing similar results. Taking all this into consideration, one can conclude that hexacyanoferrate(III) complexes form ideal anionic pillars for the creation of microporous layered double hydroxides.  相似文献   

5.
The structure of a methylamine sorption complex of fully dehydrated, fully Cd2+-exchanged zeolite X, Cd46(CH3NH2)16[Si100Al92O384]-FAU (a = 24.863(4) Å), has been determined by single-crystal X-ray diffraction techniques in the cubic space group at 21(1) °C. An aqueous exchange solution 0.05 M in Cd2+ was allowed to flow past the crystal for 5 days. The crystal was then dehydrated at 480 °C and 2 × 10−6 Torr for 2 days (colorless), and exposed to 160 Torr of methylamine gas at 21(1) °C for 2 h (yellow). Diffraction data were then gathered in this atmosphere and were refined using all data to the final error indices (based upon the 524 reflections for which Fo > 4σ(Fo)) of R1 = 0.069 and wR2 = 0.200. In this structure, Cd2+ ions occupy three crystallographic sites. The octahedral sites I at the centers of the hexagonal prisms are filled with 16 Cd2+ ions per unit cell (Cd–O = 2.369(8) Å). The remaining 30 Cd2+ ions are located at two non-equivalent sites II with occupancies of 14 and 16. The 16 methylamine molecules per unit cell lie in the supercage where each interacts with one of the latter 16 site-II Cd2+ ions: N–Cd = 2.11(8) Å. The imprecisely determined N–C bond length, 1.49(22) Å, agrees with that in gaseous methylamine, 1.474 Å. The positions of the hydrogen atoms were calculated. It appears that one of the amino hydrogen atoms hydrogen bonds to a 6-ring oxygen, and that the other forms a bifurcated hydrogen bond to this and another 6-ring oxygen. The methyl group is not involved in hydrogen bonding.  相似文献   

6.
The potential of Fe(II)-orthophenantroline photocatalyst, doped on zeolite Na-Y via complexation process, was studied in decolorization of methyl green. The characterization of samples was studied using XRD, FT-IR, TG/DTG and SEM methods. The best photodecolorization efficiency was obtained at: 1 g L−1 catalyst, 40 ppm MG, pH: 9 using catalyst containing 7 mg per gram catalyst. The degradation process obeyed first-order kinetics. The reusability of the intended catalyst was also investigated. Homogeneous photodecolorization using unsupported complex does not significant role in photodecolorization of the dye, which confirms the importance of zeolitic support to prevent the aggregation of complex particles.  相似文献   

7.
S.C. Lee  S.-H. Park  S.M. Lee  J.B. Lee  H.J. Kim   《Catalysis Today》2007,120(3-4):358-362
Monodispersed Cu2(OH)3Cl nanoplatelets, Cu(OH)2 nanowires, CuO nanoparticles and nanoribbons with a spherical morphology were synthesized using hydrothermal and heat-treatment reactions, and their H2 storage characteristics were examined. The Cu2(OH)3Cl nanoplatelets particles formed immediately after mixing the reactant, which subsequently formed larger uniform spherical particles in the submicron range. This procedure highlights a practical strategy for producing spherical Cu(OH)2 and CuO materials consisting of monodispersed nanocrystals. The spherical aggregates of Cu2(OH)3Cl nanoplatelets heat-treated at 473 K could reversibly store up to 2.35 wt.% H2 at 38 bar and 293 K.  相似文献   

8.
赵丹  赵叙  徐恩宇  杨梅 《广州化工》2011,39(8):64-65,82
基于精胺对Ru(bpy)32+电化学发光的显著增强效应,利用池内停流技术,建立了精胺的电化学发光测定法。本方法具有灵敏度高,线性范围宽和分析速度快的特点。在最优条件下,相对电化学发光值与精胺浓度在5×10-8~5×10-5mol/L范围内呈现良好的线性关系,对5×10-8mol/L浓度的精胺进行11次平行测定,其相对标准偏差为3.03%,检出限为2.31×10-8mol/L。  相似文献   

9.
研究了含有甲次膦酸酯的烯烃氢甲酰化反应及酰胺化、羰基化反应。在烯烃的氢甲酰化反应中 ,当溶剂为甲醇 ,催化剂为Co2 (CO) 8,可获得收率为 96 %的 3,3 二甲氧基丙基甲次膦酸 2 氯乙基酯 ,进一步反应可获得 (3 苯甲酰胺基 3 甲氧基羰基 )丙基甲次膦酸 2 氯乙基酯收率达 85 %。  相似文献   

10.
[Os(bpy)3]3[P2W18O62] has been synthesised and characterised by elemental analysis, spectroscopic (UV-vis, IR spectroscopy) and electrochemical techniques. In 0.1 M Bu4NPF6 DMSO the complex shows a series of redox couples associated with the Os3+/2+ and bipyridine ligands of the cationic [Os(bpy)3]2+ moiety and the tungsten-oxo framework of the associated Dawson parent heteropolyanion, [P2W18O62]6−. At this electrolyte concentration, the Os3+ redox form of the complex was seen to adsorb onto the electrode surface. When the electrolyte concentration is lowered to 0.01 M Bu4NPF6 in addition to the Os3+/2+ redox couple, the redox process associated with the [P2W18O62]8−/7− couple also exhibited properties indicating surface based processes were present. Electroactive films of the complex were formed on carbon macroelectrodes by the redox switching of the transition metal within the complex. Voltammetric investigations into the film's behaviour in a range of buffer solutions (pH 2.0, 4.5 and 7.0) were performed. The films were found to possess better stability in acidic pH and the same pH dependence for the tungsten-oxo framework of the heteropolyanions as in solution. Solid state electrochemical measurements on mechanically attached microparticles of the complex were performed, with the effect of both the nature and concentration of the aqueous electrolyte on this behaviour being investigated. Upon redox switching between the Os2+/3+ redox states, there is an associated insertion/expulsion of anions from/to the solution phase. Scanning electron micrographs of these solid state films were attained before and after redox cycling.  相似文献   

11.
Layered Li[Ni(1−x)/3Mn(1−x)/3Co(1−x)/3Crx]O2 materials with x = 0, 0.01, 0.02, 0.03, 0.05 are prepared by a solid-state pyrolysis method. The oxide compounds were calcined with various Cr-doped contents, which result in greater difference in morphological (shape, particle size and specific surface area) and the electrochemical (first charge profile, reversible capacity and rate capability) differences. The Li[Ni(1−x)/3Mn(1−x)/3Co(1−x)/3Crx]O2 powders were characterized by means of X-ray diffraction (XRD), charge/discharge cycling, cyclic voltammetry, and SEM. XRD experiment revealed that the Li[Ni(1−x)/3Mn(1−x)/3Co(1−x)/3Crx]O2 (x = 0, 0.01, 0.02, 0.03, 0.05) were crystallized to well layered -NaFeO2 structure. The first specific discharge capacity and coulombic efficiency of the electrode of Cr-doped materials were higher than that of pristine material. When x = 0.02, the sample showed the highest first discharge capacity of 241.9 mAh g−1 at a current density of 30 mA g−1 in the voltage range 2.3–4.6 V, and the Cr-doped samples exhibited higher discharge capacity and better cycleability under medium and high current densities at room temperature.  相似文献   

12.
A sensitive electrogenerated chemiluminescence (ECL) detection of DNA hybridization, based on tris(2,2′-bipyridyl)ruthenium(II)-doped silica nanoparticles (Ru(bpy)32+-doped SNPs) as DNA tags, is described. In this protocol, Ru(bpy)32+-doped SNPs was used for DNA labeling with trimethoxysilylpropydiethylenetriamine(DETA) and glutaraldehyde as linking agents. The Ru(bpy)32+-doped SNPs labeled DNA probe was hybridized with target DNA immobilized on the surface of polypyrrole (PPy) modified Pt electrode. The hybridization events were evaluated by ECL measurements and only the complementary sequence could form a double-stranded DNA (dsDNA) with DNA probe and give strong ECL signals. A three-base mismatch sequence and a non-complementary sequence had almost negligible responses. Due to the large number of Ru(bpy)32+ molecules inside SNPs, the assay allows detection at levels as low as 1.0 × 10−13 mol l−1 of the target DNA. The intensity of ECL was linearly related to the concentration of the complementary sequence in the range of 2.0 × 10−13 to 2.0 × 10−9 mol l−1.  相似文献   

13.
标题化合物(SYP-300)是沈阳化工研究院的试验除草剂。由丙基异硫氰酸酯与6-氨基-7-氟-4-炔丙基-1,4-苯并噁嗪-3-酮经两步反应制得。其结构经核磁共振谱、红外光谱和元素分析确证。SYP-300在温室条件下100ga.i./hm^2可防除多种阔叶杂草,在200ga.i./hm^2对小麦和水稻安全。  相似文献   

14.
ZrO2(3Y)包裹Al2O3纳米复合粉体的制备   总被引:2,自引:0,他引:2       下载免费PDF全文
杨建  刘姣  丘泰  林洁 《化工学报》2006,57(8):1997-2001
以pH值缓冲溶液为沉淀剂,用非均匀成核和液相共沉淀相结合的方法合成出了ZrO2(3Y)包裹Al2O3纳米复合粉体.用XRD、TEM对所制备粉体进行了表征.研究表明:加入分散剂使Al2O3悬浮液的等电点向酸性区移动,Zeta电位绝对值增大,其中pH值为9.56对应的Zeta电位绝对值最大,悬浮液最稳定.Al2O3悬浮液pH值为9.5,ZrOCl2和YCl3混合溶液浓度为0.2 mol•L-1时前驱体的收得率最高.600℃煅烧后得到的粉体中只有α-Al2O3、t-ZrO2两种物相,在Al2O3颗粒表面附着10 nm左右的ZrO2(3Y)颗粒.  相似文献   

15.
标题化合物(SYP-298)是沈阳化工研究院的试验除草剂,由邻硝基苯甲酸经5步反应制得。其结构经核磁共振谱和质谱分析确证。SYP-298在温室条件下38 g a.i./hm2可防多种阔叶杂草,在600 g a.i./hm2对玉米和水稻安全。  相似文献   

16.
标题化合物(SYP-300)是沈阳化工研究院的试验除草剂。由丙基异硫氰酸酯与6-氨基-7-氟-4-炔丙基-1,4-苯并嗪-3-酮经两步反应制得。其结构经核磁共振谱、红外光谱和元素分析确证。SYP-300在温室条件下100ga.i./hm2可防除多种阔叶杂草,在200ga.i./hm2对小麦和水稻安全。  相似文献   

17.
A typical metal organic framework, [Cu3 (BTC)2(H2O)3, BTC = 1,3,5-benzene tricarboxylate] has been used for the synthesis of pyrimidine-chalcones. We have explored a green synthesis of pyrimidine chalcones under Cu3(BTC)2 catalysis by Aldol condensation. Easy isolation of product, excellent yield, and recyclable catalyst makes this reaction eco-friendly. The technology was demonstrated to be applicable to the synthesis of a host of chemical hybrids.  相似文献   

18.
吴震宇  刘宁宁 《工业催化》2015,23(12):1013-1016
以冰乙酸和异戊醇为原料,Al_2(SO_4)_3/FeCl_3为催化剂,对催化合成乙酸异戊酯的条件进行研究。考察催化剂用量、乙酸与异戊醇物质的量比以及反应时间对乙酸酯化率的影响。结果表明,Al_2(SO_4)_3/FeCl_3具有良好的催化活性,在乙酸物质的量为0.1 mol、乙酸与异戊醇物质的量比为1∶4、催化剂用量1.0 g、反应时间2.0 h和带水剂环己烷用量10 m L反应条件下,重复实验3次,平均乙酸酯化率为93.50%。  相似文献   

19.
用浓H2SO4做催化剂,以双环戊二烯和甲醇为原料合成甲基三环癸烯醚。讨论了原料加入次序和比例、反应时间和温度、催化剂中和脱除方法对产品收率的影响,优惠合成条件为:n(H2SO4):n(双环戊二烯):n(CH3OH)约为1∶5∶15,反应温度以溶液回流温度为宜,以溶液能沉入水底或回流温度110℃左右为终点。用三乙胺或吡啶中和脱除H2SO4催化剂,蒸馏收集220~230℃馏分,产品收率高于83%。  相似文献   

20.
The introduction of epoxy groups in the polymer backbone is one of the most promising methods of modifying polydienes. In this work the performance of the classical catalytic system VO(acac)2/tert-butylhydroperoxide was evaluated for the epoxidation of polydienes. The polymers investigated were a hydroxylated poly(butadiene), two polybutadienes with high and with low 1,4-content, a poly(isoprene), and a styrene–butadiene copolymer. The epoxidized polymers were characterized by IR, 1H and 13C NMR and GPC techniques. The vanadium system was active for the epoxidation reaction and the reactivity decreases in the order HTPB>PI>1,4-PB>1,2-PBSBR. The occurrence of secondary reactions to low extension could be detected by the presence of hydroxyl, carbonyl and alcohol signals in the spectra of epoxidized polymers. Incomplete mass recovery (70–90%) was observed probably due to the chain degradation or modification of the polymer polarity.  相似文献   

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