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氟代苯甲醛是制造医药、农药、香料、染料等多种精细化工产品的中间体。综述了氟代苯甲醛化学合成方法的研究进展,包括氟代甲苯氧化法、氟代甲苯的氯化水解法、氟代苯甲醇氧化法、酯或羧酸还原法、氟苯的醛基化法、氟化法等。通过对各方法优缺点的探讨,对其工业应用前景进行了展望。 相似文献
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间接电氧化合成对溴苯甲醛 总被引:9,自引:1,他引:9
提出采用间接电合成法以Ce4+/Ce3+为媒质,在高剪切混合乳化机搅拌下使Ce4+氧化对溴甲苯合成对溴苯甲醛工艺,使用后的媒质再生循环使用,无三废排放。在隔膜电解槽中Ce3+电氧化的最佳条件是c(Ce3+)=0 8mol/L;c(H2SO4)=0 3mol/L;电流密度200A/m2;电量1 0F/mol,Ce4+的电解收率90 9%。槽外合成对溴苯甲醛的最佳条件是n(Ce4+)∶n(p Br—C6H4—CH3)=4∶1;c(H2SO4)=0 3mol/L;反应温度85℃,对溴苯甲醛反应收率78 5%,Ag+催化下对溴苯甲醛反应收率90 3%。 相似文献
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采用直径10in积分球结合CCD(Charge Coupled Device)探测器测试系统,在蓝色半导体发光二极管激发下,对Ce3 掺杂的Y3Al5O12(YAG)玻璃陶瓷的荧光光谱进行表征,实现了以荧光发射特性绝对评价为目的的绝对光谱功率分布测定,为白色LED(Light Emitting Diode)荧光材料发射特性的精确测定提供了一种准确方法。荧光测试系统经标准卤素灯定标,辅助卤素灯校正积分球内环境变化,解析出样品发光的绝对光谱功率分布,并进一步计算出光量子数分布,求得荧光量子产率。实验结果表明,YAG高效玻璃陶瓷片的荧光量子产率高达33.7%,为新型高效LED照明发光材料的研制提供了新的标准和比照。 相似文献
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《分离科学与技术》2012,47(16):2376-2382
In this work, adsorption of the Ce(IV) ions onto polypyrrole (PPy) and polyaniline (PAn) conducting electroactive polymers as coated form on sawdust has been investigated. The effect of some important parameters such as initial concentration of the Ce(IV) ion adsorbent dosage, and contact time was studied. The experiments were carried out using both batch and column systems at room temperature. The equilibrium adsorption capacity of sawdust coated by polypyrrole and polyaniline for the removal of Ce(IV) ion was measured and extrapolated using linear Freundlich and Langmuir isotherms. It was found that sawdust modified by PPy and PAn improved the removal efficiency of Ce(IV) ions from aqueous solutions greatly. 相似文献
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《Ceramics International》2022,48(22):33440-33454
This study deals with the theoretical and experimental characterizations of Bi-based hydroxyapatites (HAps) co-doped with Ce. Five samples of Bi-based HAp (at a constant amount of 0.125 at.%) with additions of the Ce in various amounts (0, 0.125, 0.25, 0.375, and 0.500 at. %) were synthesized by using the wet chemical method. The prepared samples were investigated experimentally by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, differential thermal analysis (DTA), thermogravimetric analysis (TGA), and vibrating sample magnetometer (VSM). All the samples were also modeled by using a density functional theory (DFT), and theoretical results were obtained. Both experimental and theoretical results showed that the lattice parameters and unit cell volume were significantly affected by Ce content. Calculated bandgap energy results of the samples gradually reduced from 4.6308 eV to 4.5299 eV. The bandgap decreased with increasing Ce content, and the densities of states (DOS) values were also affected by the amount of Ce. It was found that the sample doped with 0.500 at. % Ce showed the best biocompatibility among all the as-synthesized samples. The linear absorption coefficient increased with increasing amounts of Ce in all samples, while this parameter decreased with increasing photon energy. The density increases with the increasing Ce content ranging from 3.1615 g cm?3 to 3.1772 g cm?3. Both crystallite size and crystallinity decreased gradually with the increasing amount of Ce. FTIR and Raman spectra confirm the formation of the HAp structure for all the samples. 相似文献
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Adam Makowka 《分离科学与技术》2020,55(12):2193-2203
ABSTRACT This work shows application of Cyphos IL 104 (trihexyl(tetradecyl)phosphonium bis(2,4,4-trimethylpentyl)phosphinate) as the extractant and the ion carrier of Ce(III) and La(III) from aqueous solutions through polymer inclusion membranes (PIM). These membranes were used for separation of Ce(III) from solution containing La(III), Cu(II), Co(II) and Ni(II). The best results of the separation process were obtained for PIM containing: 20.0 wt.% CTA, 55.0 wt.% NPOE and 25.0 wt.% Cyphos IL 104 at pH 3.8 into 1 M H2SO4. The separation coefficients were found in order of S Ce/La < S Ce/Cu < S Ce/Co < S Ce/Ni. 相似文献
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废选择性催化还原(SCR)脱硝催化剂中含有大量的有价金属,直接废弃易造成资源浪费及环境污染。以废CeO x -MnO x 基SCR脱硝催化剂为原料,采用热力学分析结合湿法冶金实验方法,研究了浸出条件对Ce、Mn元素浸出率的影响。结果表明,废催化剂直接酸浸Ce、Mn元素浸出率低,还原-酸浸Ce、Mn元素热力学条件上可行,抗坏血酸对Ce、Mn高价氧化物有明显的还原作用。当抗坏血酸质量分数为30%、硫酸浓度2mol/L、液固比6∶1、搅拌速度350r/min、80℃恒温反应5h时,Ce、Mn的浸出率分别达到92.09%、95.51%。加入抗坏血酸后,部分Ce4+和Mn4+还原为Ce3+和Mn2+,Ce4+/Ce的比值由75.82%降低到71.62%,Mn4+/Mn的比值由29.39%降低到27.17%,同时削弱了高价Ce辅助低价Mn向高价Mn转化的作用,使得Ce、Mn高效浸出,为CeO x -MnO x 基废催化剂中Ce、Mn资源化利用奠定了基础。 相似文献
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利用溶胶-凝胶法将[C8 mim]PF6和二(2-乙基己基)磷酸(HDEHP)固定在固体硅胶复合材料上。离子液体[C8 mim]PF6在反应过程中作为溶剂,为HDEHP提供了一个可以扩散的介质。复合材料对Ce(Ⅲ)的萃取主要取决于HDEHP与金属离子的络合作用。首先利用SEM和红外表征了复合材料的表面形貌和化学成分,然后研究了复合材料对金属离子Ce(Ⅲ)的吸附性能。考察了不同复合材料、振荡时间对Ce(Ⅲ)吸附性能的影响。结果表明,该复合材料对Ce(Ⅲ)有较好的萃取效果。用硅的复合材料进行金属离子的固液萃取可以是一种有效的方法。 相似文献
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利用溶胶-凝胶法将[C8 mim]PF6和二(2-乙基己基)磷酸(HDEHP)固定在固体硅胶复合材料上。离子液体[C8 mim]PF6在反应过程中作为溶剂,为HDEHP提供了一个可以扩散的介质。复合材料对Ce(Ⅲ)的萃取主要取决于HDEHP与金属离子的络合作用。首先利用SEM和红外表征了复合材料的表面形貌和化学成分,然后研究了复合材料对金属离子Ce(Ⅲ)的吸附性能。考察了不同复合材料、振荡时间对Ce(Ⅲ)吸附性能的影响。结果表明,该复合材料对Ce(Ⅲ)有较好的萃取效果。用硅的复合材料进行金属离子的固液萃取可以是一种有效的方法。 相似文献
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Undoped and Ni, Ce-doped nanocrystalline tin oxide were synthesized by co-precipitation route. Doped as well as undoped SnO2 compositions revealed single phase structure without any impurity. The lattice constant of SnO2 increases and the grain size decreases with doping of Ni and Ce. The responses of the sensing elements are evaluated by measuring the resistance change upon exposure to various test gases such as liquid petroleum gas (LPG), acetone, ethanol and ammonia. In comparison to LPG, ethanol, and ammonia the response towards acetone vapor increases markedly on simultaneous doping of Ni and Ce. For acetone vapors with 500 ppm at 300 °C, the undoped SnO2 shows 31% response, while with individual Ni or Ce doping it increases to 38 and 60%, respectively, however with simultaneous doping of Ni and Ce there is a significant enhancement up to 92%. The results of gas sensing measurements reveal that the thick films deposited on alumina substrates using screen printing technique give selectively a high response of (87%) with fast recovery (∼1 min) towards 100 ppm acetone at 300 °C. 相似文献
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The electrochemical behaviour of the complexation of cerium(IV) with EDTA and DTPA was studied using both cyclic voltammetry
(CV) and rotating disc electrode (RDE). The Ce(IV)–DTPA complex at various scan rates gave a linear correlation between the
peak potential (E
p
) and square root of scan rate, showing that the kinetics of the overall process was controlled by mass transport. However,
when the EDTA ligand was added to the Ce(IV) there was no specific change to the potential peak, i.e. the Ce(IV)–EDTA complex
has the same redox potential as the Ce(IV)/(III) couple. Kinetic parameters such as potential, limiting current, diffusion
coefficients, transfer coefficient and rate constants were studied. The results from RDE experiments confirmed that the parameters
measured by CV are similar under hydrodynamic conditions and can be used to determine the kinetic parameters of the redox
couples. The use of DTPA as a ligand for complexation of Ce(IV) gaves more favourable results compared to the Ce–(EDTA) complex
reported previously. The results of kinetic studies of Ce(IV)–DTPA complex shows promise as an electrolyte for redox flow
battery. 相似文献
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Sushanta Kumar Sahu 《分离科学与技术》2016,51(3):447-456
The effect of parameters like shaking time, nitric acid, nitrate ion, extractant concentration, temperature, diluents, and phase volume ratio on the extraction of Ce(III) from acidic nitrate medium using binary mixture of Cyanex 921 and Cyanex 923 in kerosene has been investigated. Synergism was observed in the range 0.001-1.0 mol/L HNO3. With increase in extractant concentration and O/A phase volume ratio, extraction increases while with increase in nitric acid concentration and temperature, extraction decreases. Sulphuric acid and hydrochloric acid are found to be effective in stripping. Separation factors for Nd/Ce are higher as compared to those for Ce/La and Pr/Ce. 相似文献