调节pH值合成Fe-SBA-16分子筛

调节pH值合成不同铁含量的Fe-SBA-16-x-y介孔分子筛。采用X射线衍射、N_2物理吸附-脱附、FT-IR、UV-vis对样品结构进行表征,并通过苯酚羟基化反应考查其催化活性。结果表明:合成的Fe-SBA-16-x-y催化剂保持了SBA-16介孔分子筛的有序结构和高的比表面积,且铁成功地引入到分子筛的骨架中。当反应温度为65℃,反应时间为2h,苯酚∶双氧水为1∶0.4时,Fe-SBA-16-50-3催化活性较好。     

Fe/SBA-16介孔分子筛催化苯选择氧化性能研究

本文考察了不同负载量的Fe/SBA- 16催化剂对苯选择氧化制备苯酚催化活性的影响.运用小角XRD、N2吸附及紫外漫反射光谱对催化剂的结构和催化剂表面活性物种进行研究.结果表明:Fe/SBA-16催化剂保持了SBA-16介孔分子筛的三维立方的孔道结构,高分散的铁物种是催化反应的活性物种.     

SBA-15固载磷钨酸催化剂的制备及催化合成叔丁基苯酚

以不同硅烷偶联剂改性的介孔分子筛SBA-15为载体、PW_(12)为催化剂,通过对SBA-15表面共价及非共价修饰制备磷钨酸@介孔分子筛/硅烷偶联剂复合催化剂PW_(12)@SBA-15/YSiX_3(YSiX_3=Apts、Atapts、Papts);并利用FT-IR、XRD、TEM、N_2吸附-脱附对其组成、结构及形貌进行表征。以改性SBA-15分子筛固载磷钨酸催化剂催化合成叔丁基苯酚为研究对象,考察不同硅烷偶联剂、反应温度、苯酚与叔丁醇物质的量比对催化合成叔丁基苯酚的影响,并获得合成叔丁基苯酚的最佳工艺条件,即反应温度145℃、n(苯酚)∶n(叔丁醇)=1∶2.5、重时空速2.2 h~(-1),该最佳反应条件下,PW_(12)@SBA-15/Apts催化剂催化合成叔丁基苯酚的催化活性最高,苯酚转化率为98.3%,2,4-二叔丁基苯酚选择性为57.3%.     

微波辅助ZrO2-SO2-4/SBA-15催化合成棕榈酸甲酯

以三嵌段醚共聚物P123作为模板剂、正硅酸乙酯为硅源,合成介孔分子筛SBA-15。以SBA-15为载体,利用尿素水解法制备ZrO₂-SO^2-₄改性的固体酸催化剂,对其进行表征。实验结果表明,合成的固体酸催化剂具有典型的介孔结构特征。将催化剂应用于微波法催化合成棕榈酸甲酯,考察反应时间、反应温度、辐射功率、酸醇物质的量比和催化剂用量对酯化率的影响,结果表明,在n（十六酸）∶n（甲醇）=1∶15、SZ/SBA-15催化剂用量0.8 g、反应时间20 min、反应温度40 ℃和微波辐射功率400 W条件下,酯化率可达87.70%,微波反应时间较传统合成方法大大缩短。     

M/SBA-15(M=Cu、Fe、Cr)介孔分子筛的制备、表征及其催化NO+CO反应研究

以介孔分子筛SBA-15为载体,采用浸渍法制备M/SBA-15(M=Cu、Fe、Cr) 介孔分子筛催化剂。采用XRD、BET、FT-IR、H₂-TPR和XPS等对样品进行分析表征,在固定床微型反应器中评价M/SBA-15(M=Cu、Fe、Cr)分子筛催化剂催化NO+CO的反应性能。结果表明,负载金属的SBA-15分子筛仍保持高度有序的二维六方介孔结构,比表面积和孔径略有减少,负载的活性金属组分在SBA-15分子筛表面具有较高的分散度。Cu/SBA-15、Cr/SBA-15和Fe/SBA-15催化剂对NO+CO反应体系均有一定活性,但由于活性金属自身的特性及其在载体表面负载量的差异,3种催化剂上呈现的NO还原活性不同,顺序为：Cr/SBA-15＞Cu/SBA-15＞Fe/SBA-15。     

Cr-SBA-16介孔分子筛的制备及其催化性能研究

采用水热合成法直接合成不同铬含量的Cr-SBA-16-x介孔分子筛。采用X射线衍射、N2物理吸附-脱附、红外光谱、紫外-可见漫反射光谱对其进行表征。并将Cr-SBA-16-x应用于双氧水氧化环己烷氧化反应中,考察其催化活性。结果表明,合成的Cr-SBA-16催化剂保持了SBA-16介孔分子筛的有序结构和高的比表面积,且铬成功地引入到分子筛的骨架中。反应温度80℃、环己烷2 mL、双氧水2mL、催化剂0.1g、反应时间4h,Cr-SBA-16-30转化率较高。     

铁改性HMS催化氧化苯甲醇合成苯甲醛

以十二胺为模板在中性条件下合成了Fe-HMS介孔分子筛,研究了不同硅铁比Fe-HMS对苯甲醇催化氧化反应的影响。利用XRD、BET、SEM和H₂-TPR等方法对合成的催化剂进行了表征。考察了Fe-HMS对苯甲醇氧化反应的影响。结果表明,Fe³⁺ 离子进入了分子筛骨架,Fe-HMS分子筛具有均一的蠕虫状介孔结构。焙烧后的Fe-HMS中Fe³⁺ 主要以Fe₂O₃形式存在于骨架中。对苯甲醇液相选择性氧化反应,Fe-HMS分子筛的催化活性高于Fe-SiO₂。在85℃、Si/Fe摩尔比为25∶1、醇/双氧水摩尔比为1∶2、催化剂含量为4%、反应时间4 h条件下,苯甲醇的转化率和苯甲醛的选择性分别为65.1%和74.6%。     

钾离子对一步法制甲硫醇钼基催化剂的影响

选用具有高比表面积的介孔分子筛SBA-15作为载体,采用等体积浸渍法制备Mo/SBA-15和KMo/SBA-15催化剂并用于一步法合成甲硫醇,并采用氮气吸脱附（BET）、X射线衍射分析（XRD）、拉曼光谱（Raman）、X射线光电子能谱分析（XPS）等进行表征,研究钾离子的添加对催化合成甲硫醇的影响。结果表明,K的添加大幅提升了Mo/SBA-15的甲硫醇选择性和CO的转化率;在高浓度H₂S环境下,KMo/SBA-15催化剂上甲硫醇选择性达到了62%,高于目前文献报道的催化剂。Raman、XPS表征结果表明,添加K的催化剂上硫化后加氢脱硫活性相MoS₂含量增多。     

K_2O/SBA-15的制备及其催化性能研究

以介孔分子筛SBA-15为载体,负载KNO3后焙烧制得K2O/SBA-15固体碱催化剂,以合成丙烯酸正丁酯的酯交换反应为探针反应,在间歇式反应釜中对K2O/SBA-15催化剂进行催化活性评价。结果表明,当K2O负载量为2%,K2O/SBA-15催化剂对此酯交换反应的催化活性最高。     

SBA-15的改性及催化文冠果油制备生物柴油

以介孔分子筛SBA-15为载体,采用直接合成法和后合成法镀饰Al后再负载碱金属盐KNO₃,制得负载型固体碱催化剂KNO₃-AlSBA-15和KNO₃-Al-SBA-15。用XRD、BET、SEM以及CO₂-TPD对催化剂进行表征。结果表明：在SBA-15上镀饰Al可以保护分子筛的介孔结构;进一步负载KNO₃,能够增强催化剂的碱性。将其应用于催化文冠果油酯交换制备生物柴油,结果显示催化剂KNO₃-Al-SBA-15的催化活性最好,优于传统均相催化剂,所得生物柴油产率可达92%,重复使用多次仍具有较好的催化效果。     

Characterization and catalytic properties of mesoporous CuO/SBA-16 prepared by different impregnation methods

CuO/SBA-16 catalysts were prepared by two different routes – the conventional impregnation method and the modified impregnation method with pH adjustment. These catalysts were characterized by X-ray diffraction (XRD), atomic absorption spectrometry (AAS), N₂ physisorption and hydrogen temperature programmed reduction (H₂-TPR) measurements which reveal that the cubic cage-like (Im3m) pore structure of the parent SBA-16 molecule sieves was well maintained throughout the synthesis. After introduction of Cu, a different CuO dispersion exists on these catalysts. The CuO/SBA-16 prepared by modified impregnation method has a single highly dispersed CuO which is considered as a highly efficient species for hydroxylation of phenol with H₂O₂. CuO/SBA-16 prepared by the conventional impregnation method shows the presence of bulk CuO species which is undesirable for this reaction.     

OXIDATIVE REACTIONS OF PHENOL AND CHLOROBENZENE WITH IN SITU ELECTROGENERATED FENTON'S REAGENT

Oxidative reactions of phenol and chlorobenzene with electrogenerated Fenton's reagent, Fe²⁺ + H₂O₂, were investigated. The electrogeneration of H₂O₂ and the regeneration of Fe²⁺ were performed at a graphite cathode. Results are compared for conventional vs. electrogenerated Fenton's reagent. It was found that the conversion of chlorobenzene was substantially greater by the electrochemical method than the conventional system. The rates of H₂O₂ generation were dependent on solution pH; electrogeneration was favored at low pH, while the opposite was the case for the hydroxylation of the organics. The hydroxylation products of phenol with electrogenerated Fenton's reagent included hydroquinone, catechol and resorcinol. For chlorobenzene, a hydroxylated product (p-chlorophenol) and a dehalogenated product (phenol) were obtained. The rates of phenol and chlorobenzene hydroxylation were dependent on pH, and concentrations of F²⁺ and H₂O₂. Results indicated that the electrochemical system provided an efficient way to regenerate Fe²⁺     

水解剂氟化铵对Fe-SBA-15结构及催化性能的影响

通过水热法制备了Fe-SBA-15介孔材料,探究了水解剂氟化铵对介孔材料结构及对苯酚羟基化反应的影响。采用X射线衍射（XRD）、红外光谱（FT-IR）和氮气吸附-脱附等方法对介孔材料进行了表征,用苯酚羟基化反应对改性后介孔材料的催化性能进行了研究。结果表明:改性后的介孔材料具有良好的催化性能,其中氟与硅物质的量比为0.03时制备的介孔材料的催化性能更为优良,在固定反应条件下苯酚转化率达到36.82%、苯二酚选择性达到81.76%。     

Phenol hydroxylation using Fe-MCM-41 catalysts

Highly ordered iron-containing mesoporous material, Fe-MCM-41, with 0.5–4 Fe/Si mol% loading was prepared and characterization was performed using XRD, SEM/TEM, EDS, N₂-sorption, and FT-IR and UV–vis spectroscopies. Fe-MCM-41 exhibited high catalytic activity in phenol hydroxylation using H₂O₂ as oxidant, giving phenol conversion of ca. 60% at 50 °C [phenol:H₂O₂ = 1:1, water solvent]. Effects of Fe contents in Fe-MCM-41 and catalyst concentration, temperature, solvent used, phenol/H₂O₂ mole ratios and H₂O₂ feeding method, and catalyst calcination temperature on conversion profiles were examined. Catalyst recycling was performed to investigate the extent of potential metal leaching. Comparisons in performance were also made using nano-sized Fe₂O₃ particles and Fe-salt impregnated MCM-41 as catalyst. Catechol to hydroquinone in product ratio was close to 2:1 in accordance with a free radical reaction scheme involving Fe²⁺/Fe³⁺ redox pair and the larger amount of Fe species always achieved the given phenol conversion at a shorter reaction time. As the calcination temperature increases from 400 to 800 °C increasing amount of Fe species came out from the MCM-41 framework. Both tetrahedral Fe and extra-framework Fe species were found catalytically active, but high dispersion of Fe species achieved in Fe-MCM-41 was an advantage.     

The kinetics of phenol decomposition under UV irradiation with and without H2O2 on TiO2, Fe–TiO2 and Fe–C–TiO2 photocatalysts

H₂O₂ used in the photo-Fenton reaction with iron catalyst can accelerate the oxidation of Fe²⁺ to Fe³⁺ under UV irradiation and in the dark (in the so called dark Fenton process). It was proved that conversion of phenol under UV irradiation in the presence of H₂O₂ predominantly produces highly hydrophilic products and catechol, which can accelerate the rate of phenol decomposition. However, while H₂O₂ under UV irradiation could decompose phenol to highly hydrophilic products and dihydroxybenzenes in a very short time, complete mineralization proceeded rather slowly. When H₂O₂ is used for phenol decomposition in the presence of TiO₂ and Fe–TiO₂, decrease of OH radicals formed on the surface of TiO₂ and Fe–TiO₂ has been observed and photodecomposition of phenol is slowed down. In case of phenol decomposition under UV irradiation on Fe–C–TiO₂ photocatalyst in the presence of H₂O₂, marked acceleration of the decomposition rate is observed due to the photo-Fenton reactions: Fe²⁺ is likely oxidized to Fe³⁺, which is then efficiently recycled to Fe²⁺ by the intermediate products formed during phenol decomposition, such as hydroquinone (HQ) and catechol.     

Fabrication and catalytic performance of meso-ZSM-5 zeolite encapsulated ferric oxide nanoparticles for phenol hydroxylation

An encapsulation-structured Fe₂O₃@meso-ZSM-5 (Fe@MZ5) was fabricated by confining Fe₂O₃ nanoparticles (ca. 4 nm) within the ordered mesopores of hierarchical ZSM-5 zeolite (meso-ZSM-5), with ferric oleate and amphiphilic organosilane as the iron source and meso-porogen, respectively. For comparison, catalysts with Fe₂O₃ (ca. 12 nm) encapsulated in intra-crystal holes of meso-ZSM-5 and with MCM-41 or ZSM-5 phase as the shell were also prepared via sequential desilication and recrystallization at different pH values and temperatures. Catalytic phenol hydroxylation performance of the as-prepared catalysts using H₂O₂ as oxidant was compared. Among the encapsulation-structured catalysts, Fe@MZ5 showed the highest phenol conversion and hydroquinone selectivity, which were enhanced by two times compared to the Fe-oxide impregnated ZSM-5 (Fe/Z5). Moreover, the Fe-leaching amount of Fe@MZ5 was only 3% of that for Fe/Z5. The influence of reaction parameters, reusability, and ·OH scavenging ability of the catalysts were also investigated. Based on the above results, the structure-performance relationship of these new catalysts was preliminarily described.     

Phenol cogeneration with electricity by using in situ generated H2O2 in a H2–O2 PEMFC reactor

In the present work, direct hydroxylation of benzene to phenol by using in situ generated H₂O₂ with electricity cogeneration was carried out in a proton exchange membrane fuel cell (PEMFC) reactor. Phenol was produced only when there was current through the external circuit. No other organic products were detected during this electrochemical process. A rotating ring-disc electrode (RRDE) technique was used to quantitatively detect the intermediate H₂O₂ in an acid electrolyte solution at different potentials and temperatures. The RRDE studies showed that the in situ generated H₂O₂ may play a crucial role during the formation of phenol. The formation rate of phenol could be controlled by adjusting the current or cell potential.     

β-FeOOH改性蒙脱土复合过氧化氢对罗丹明B的降解

用不同物质的量的β-FeOOH对蒙脱土（MMT）进行改性制备出一系列β-FeOOH-MMT（x）,并将其与过氧化氢（H₂O₂）联用降解罗丹明B（RhB）。考察了RhB模拟废水脱色的影响因素,并研究了不同处理方法的协同效应。结果表明：在pH为5.2、β-FeOOH-MMT（3.5）用量为2 g/L、n（H₂O₂）∶n（Fe）=50∶1条件下搅拌10 min,对20 mg/L的RhB去除率可高达89.3%;对β-FeOOH-MMT（x）进行了拉曼光谱和扫描电镜表征。β-FeOOH-MMT（3.5）表现出丰富的孔结构;β-FeOOH-MMT（3.5）和H₂O₂对降解RhB模拟废水产生了协同效应,降解反应较为接近表观一级动力学,速率增强因子可达到29.32。     

磷钨酸/SBA-15催化氧化-萃取柴油脱硫

以自制的SBA-15为载体,磷钨酸为活性组分,用过量浸渍法制备了HPW/SBA-15催化剂,并采用SEM、BET和TG-DTA对催化剂进行表征分析。H₂O₂为氧化剂,十六烷基三甲基溴化铵（CTAB）为相转移剂,以二苯并噻吩（DBT）的模型化合物（DBT为溶质、正辛烷为溶剂）进行氧化脱除为探针反应,考察了磷钨酸负载量和HPW/SBA-15的焙烧温度对催化剂活性的影响,同时考察了氧化-萃取工艺条件对真实柴油脱硫效果的影响。实验结果表明,磷钨酸最佳负载量为30%,HPW/SBA-15在250℃焙烧处理时活性最高;在n(H₂O₂)：n(S)=6、HPW/SBA-15用量为2.5%（基于柴油质量）、CTAB用量为0.4%（基于柴油质量）、萃取级数为4、温度60℃反应1.5h的条件下,柴油硫含量从1317mg/L降到39mg/L,脱硫率达到97.0%、收率不低于85.0%。气相色谱结果显示,该催化氧化脱硫体系容易脱除柴油中加氢难以脱除的二苯并噻吩及其衍生物。     

Fe-D72树脂催化苯酚羟基化反应实验研究

利用D72离子交换树脂作为载体与铁离子进行离子交换制备Fe-D72树脂催化剂,将其运用到苯酚羟基化反应中。通过单因素法研究催化剂的含铁量、反应温度、反应时间、催化剂用量、苯酚（PH）/过氧化氢（H₂O₂）物质的量之比对苯酚羟基化反应的影响;采用L₉（3⁴）正交表设计正交试验,结果表明：n（PH）/n（H₂O₂）和反应温度对苯二酚收率的影响最大;在考察的正交范围内,n（PH）/n（H₂O₂）=1,反应温度为70 ℃,反应时间为1 h,催化剂量为0.1 g时催化效果最好,此时苯酚转化率为42.4%,苯二酚选择性为94.1%,苯二酚收率为39.8%。Fe-D72催化剂连续重复利用4次,催化稳定性较好。