胺功能化MIL-101(Cr)@SiO_2@Fe_3O_4催化剂及其Knoevenagel反应性能

采用溶剂热法在纳米SiO_2@Fe_3O_4磁性颗粒表面原位合成MIL-101(Cr),制备磁性MIL-101(Cr)@SiO_2@Fe_3O_4催化剂。采用甲胺、乙二胺和丁二胺对制备的磁性催化剂进行功能化,得到胺功能化NH2-MIL-101(Cr)@SiO_2@Fe_3O_4催化剂。利用XRD、FT-IR、BET、SEM、TEM和VSM等对催化剂结构进行表征,评价胺功能化NH2-MIL-101(Cr)@SiO_2@Fe_3O_4催化剂对糠醛和氰乙酸乙酯Knoevenagel缩合反应性能和重复使用性能,考察反应条件与催化性能的关系。结果表明,制备的新型胺功能化NH2-MIL-101(Cr)@SiO_2@Fe_3O_4催化剂具有MIL-101(Cr)的结构特征和良好的超顺磁性能,对糠醛和氰乙酸乙酯Knoevenagel缩合反应表现出很好的催化性能,其中,乙二胺功能化30%MIL-101(Cr)@SiO_2@Fe_3O_4催化剂对Knoevenagel缩合反应的性能最佳,在反应温度40℃和反应时间1 h条件下,氰乙酸乙酯转化率为97. 0%,产物选择性接近100%。反应后磁性催化剂可以通过外磁场容易进行分离,重复使用5次,氰乙酸乙酯转化率仍大于93%。     

N-甲基苯胺和N，N-二甲基苯胺合成研究进展

基于苯胺N-甲基化反应在苯胺N-烷基化反应系列中的特殊性,介绍了近年来涉及合成N-甲基苯胺和N,N-二甲基苯胺的重要研究进展,分别对气相法和液相法制备N-甲基苯胺和N,N-二甲基苯胺的合成工艺进行了分析。认为液相法N-甲基化反应具有反应工艺路线可变性好、可通过耦合等方法来弥补其不足之处,具有一定的研究前景。而气相合成法还不具备完全取代液相合成法的优势。     

N-甲基苯胺和N，N-二甲基苯胺合成研究进展

基于苯胺N-甲基化反应在苯胺N-烷基化反应系列中的特殊性,介绍了近年来涉及合成N-甲基苯胺和N,N-二甲基苯胺的重要研究进展,分别对气相法和液相法制备N-甲基苯胺和N,N-二甲基苯胺的合成工艺进行了分析.认为液相法N-甲基化反应具有反应工艺路线可变性好、可通过耦合等方法来弥补其不足之处,具有一定的研究前景.而气相合成法还不具备完全取代液相合成法的优势.     

Al改性Cu/ZnO催化剂催化苯胺制备二甲基苯胺

通过沉积沉淀法对Al改性Cu/ZnO催化剂进行研究,并利用XRD、BET、NH₃-TPD等对催化剂进行表征。同时对苯胺和甲醇N-甲基化反应制备N,N-二甲基苯胺(N,N-DMA)进行研究,对沉积沉淀法制备的催化剂进行了焙烧条件考察及对N-甲基化反应进行工艺条件优化。结果表明,在拟薄水铝石为铝源、Cu/Zn/Al摩尔比为1:3:1、焙烧温度为400 ℃,焙烧时间为3 h,反应温度为250 ℃,反应压力为1.5 MPa,进料空速为0.3 h^_-1,氮气流量为150 mL/min,苯胺与甲醇摩尔比为为1:7时,苯胺N-甲基化反应效果最佳,苯胺转化率达99.8%,N,N-DMA选择性达92.8%,催化剂进行了720 h稳定性实验,苯胺转化率稳定在99%以上,N,N-DMA选择性稳定在90%以上,催化剂稳定性较好。     

MIL-101(Cr)催化单过硫酸氢钾降解罗丹明B

采用水热合成法制备金属有机骨架材料MIL-101(Cr),以MIL-101(Cr)为催化剂催化PMS产生SO~-_4·降解RhB。采用SEM、EDS及XRD对制备的MIL-101(Cr)进行表征,表征结果证明成功合成了MIL-101(Cr);对照试验证明MIL-101(Cr)具有催化活性;反应条件试验说明MIL-101(Cr)催化性能受催化剂投加量、氧化剂投加量和pH的影响;循环使用试验证明MIL-101(Cr)具有一定的循环使用性。当MIL-101(Cr)投加量为0.6 g/L、PMS投加量为0.5 g/L、pH值为6.5时,RhB的降解率可达93.3%。     

Au-Ru/TiO2催化硝基苯和苯甲醛一锅法合成N-苄基苯胺

采用沉积-沉淀法制备出一系列Au-Ru/TiO2双金属催化剂,用于硝基苯与苯甲醛一锅法加氢反应合成N-苄基苯胺。考察了Ru负载量对Au-Ru/TiO2加氢性能的影响,并采用X射线衍射和扫描电镜等方法对催化剂进行表征。结果表明,Au和Ru产生协同作用共同促进加氢作用。负载Ru质量分数为1.5%的催化剂具有最好的加氢活性和N-苄基苯胺选择性。优化的N-苄基苯胺合成工艺条件为：催化剂用量占硝基苯质量的15%,溶剂为甲苯,氢压1.1 MPa,反应温度80 ℃。此条件下,硝基苯转化率100%,N-苄基苯胺选择性88.2%     

Au@Co/MIL-101的合成及其催化氧化肉桂醇的研究

金属有机骨架材料(MOFs)是近十年来发展非常迅速的一种配位聚合物,它是由有机化合物配体化合物与无机金属离子组成的三维网状结构的类沸石材料。通过以MIL-101为载体,采用溶胶法合成了Au@Co/MIL-101催化剂。并采用粉末X射线衍射谱扫描电子显微镜等手段对制得的Au@Co/MIL-101材料进行表征,随后将此材料用于肉桂醇催化氧化为肉桂醛的实验中,以此研究Au@Co/MIL-101的催化性能。通过实验探究了温度对Au@Co/MIL-101材料的催化性能的影响,实验结果表明该材料在100℃时催化肉桂醇的反应的产率是最高的。     

不同晶体形貌NH2-MIL-125(Ti)制备及光催化性能

采用溶剂热法合成了NH2-MIL-125(Ti)晶体，通过调变N,N-二甲基甲酰胺（DMF）和无水甲醇（MeOH）两种溶剂比例，NH2-MIL-125(Ti)晶体呈现出圆形片、十面体和八面体形貌。采用XRD、SEM、FT-IR和BET等表征手段对不同形貌的NH2-MIL-125(Ti)晶体进行物性分析，并将其用于可见光光催化环己烷氧化反应，探究了催化性能与晶面之间的构效关系。分析得出， 环己烷选择性氧化生成环己醇和环己酮目标产物主要反应发生在NH2-MIL-125(Ti)晶体的{110}晶面族，而{101}晶面族主要是进一步氧化环己醇和环己酮产生COx。     

不同氨基修饰条件对NH_2-MIL-53(Al)CO_2吸附性能的影响

采用水热合成法,通过改变配体中2-氨基对苯二甲酸的含量制备了不同氨基含量的NH2-MIL-53(Al),考察了氨基含量,氨基功能化方法和氨基种类对NH2-MIL-53(Al)的CO2吸附性能的影响。傅里叶变换红外光谱表征(IR)发现在3500~3900 cm?1处存在—NH2基的伸缩振动带,氨基修饰成功。低压下,NH2-MIL-53(Al)的CO2吸附容量随氨基含量的增加而增大,且当氨基含量100%时,其CO2吸附性能优于直接合成的NH2-MIL-53(Al)。合成前修饰比合成后修饰,更有利于提高CO2吸附容量。采用乙醇胺、1,8-二氮杂二环[5.4.0]十一碳-7-烯、N,N′-二亚乙基三胺进行后氨基功能化都不能提高MIL-53的CO2吸附能力。     

三氯氧磷催化N-烷基化制备N-乙基苯胺和N,N-二乙基苯胺

以三氯氧磷为催化剂,由苯胺和乙醇反应制备了N-乙基苯胺和N,N-二乙基苯胺,考察了温度、压力、催化剂用量、醇胺摩尔比、反应时间等因素对该反应的影响.结果表明,三氯氧磷催化苯胺和乙醇反应的较佳工艺条件为:V(C6H7N):V(C2H5OH):V(POCl3)=55:70:2,温度493 K,N2压力4.0 MPa,反应时...     

不同氨基修饰条件对NH2-MIL-53(Al)CO2吸附性能的影响

采用水热合成法,通过改变配体中2-氨基对苯二甲酸的含量制备了不同氨基含量的NH₂-MIL-53（Al）,考察了氨基含量,氨基功能化方法和氨基种类对NH₂-MIL-53（Al）的CO₂吸附性能的影响。傅里叶变换红外光谱表征（IR）发现在3500～3900 cm^-1处存在-NH₂基的伸缩振动带,氨基修饰成功。低压下,NH₂-MIL-53（Al）的CO₂吸附容量随氨基含量的增加而增大,且当氨基含量100%时,其CO₂吸附性能优于直接合成的NH₂-MIL-53（Al）。合成前修饰比合成后修饰,更有利于提高CO₂吸附容量。采用乙醇胺、1,8-二氮杂二环[5.4.0]十一碳-7-烯、N,N'-二亚乙基三胺进行后氨基功能化都不能提高MIL-53的CO₂吸附能力。     

Conversion of CO into CO2 by high active and stable PdNi nanoparticles supported on a metal-organic framework

The solubility of Pd(NO₃)₂ in water is moderate whereas it is completely soluble in diluted HNO₃ solution. Pd/MIL-101(Cr) and Pd/MIL-101-NH₂(Cr) were synthesized by aqueous solution of Pd(NO₃)₂ and Pd(NO₃)₂ solution in dilute HNO₃ and used for CO oxidation reaction. The catalysts synthesized with Pd(NO₃)₂ solution in dilute HNO₃ showed lower activity. The aqueous solution of Pd(NO₃)₂ was used for synthesis of mono-metal Ni, Pd and bimetallic PdNi nanoparticles with various molar ratios supported on MOF. Pd₇₀Ni₃₀/MIL-101(Cr) catalyst showed higher activity than monometallic counterparts and Pd+ Ni physical mixture due to the strong synergistic effect of PdNi nanoparticles, high distribution of PdNi nanoparticles, and lower dissociation and desorption barriers. Comparison of the catalysts synthesized by MIL-101(Cr) and MIL-101-NH₂(Cr) as the supports of metals showed that Pd/MIL-101-NH₂(Cr) outperforms Pd/MIL-101-(Cr) because of the higher electron density of Pd resulting from the electron donor ability of the NH₂ functional group. However, the same activities were observed for Pd₇₀Ni₃₀/MIL-101(Cr) and Pd₇₀Ni₃₀/MIL-101-NH₂(Cr), which is due to a less uniform distribution of Pd nanoparticles in Pd₇₀Ni₃₀/MIL-101-NH₂(Cr) originated from amorphization of MIL-101-NH₂(Cr) structure during the reduction process. In contrast, Pd₇₀Ni₃₀/MIL-101(Cr) revealed the stable structure and activity during reduction and CO oxidation for a long time.     

Synthesis of mixed alcohols from CO2 contained syngas on supported molybdenum sulfide catalysts

The performances of active carbon supported molybdenum sulfide catalysts prepared by different procedures or promoted by different elements in the synthesis of mixed alcohols from CO₂ containing syngas were examined. The results showed that high alcohol activity and selectivity could be obtained by employing a rapid drying procedure and employing a H₂S---H₂ stream for (NH₄)₂MoS₄ decomposition. Addition of Co, Cr and Cl to K---Mo/C catalyst led to an increase in the alcohol activity or selectivity. The presence of CO₂ in the feed caused a greater amount of water to be produced but reduced the formation of CO₂. The product distribution was also strongly influenced by the presence of either CO₂ or H₂S in the feed. Addition of CO₂ reduces the formation of higher alcohols while H₂S increases higher alcohol formation.     

Coke study on MgO-promoted Ni/Al2O3 catalyst in combined H2O and CO2 reforming of methane for gas to liquid (GTL) process

MgO-promoted Ni/Al₂O₃ catalysts have been investigated with respect to catalytic activity and coke formation in combined steam and carbon dioxide reforming of methane (CSCRM) to develop a highly active and stable catalyst for gas to liquid (GTL) processes. Ni/Al₂O₃ catalysts were promoted through varying the MgO content by the incipient wetness method. X-ray diffraction (XRD), BET surface area, H₂-temperature programmed reduction (TPR), H₂-chemisorption and CO₂-temperature programmed desorption (TPD) were used to observe the characteristics of the prepared catalysts. The coke formation and amount in used catalysts were examined by SEM and TGA, respectively. H₂/CO ratio of 2 was achieved in CSCRM by controlling the feed H₂O/CO₂ ratio. The catalysts prepared with 20 wt.% MgO exhibit the highest catalytic performance and have high coke resistance in CSCRM. MgO promotion forms MgAl₂O₄ spinel phase, which is stable at high temperatures and effectively prevents coke formation by increasing the CO₂ adsorption due to the increase in base strength on the surface of catalyst.     

WO_3负载量对V_2O_5/WO_3-TiO_2催化剂脱硝性能的影响

采用V_2O_5/WO_3-TiO_2作为脱硝催化剂,考察活性组分V_2O_5和助剂WO_3负载量对催化剂脱硝活性和抗硫抗水性能的影响。结果表明,3%V_2O_5/x WO_3-TiO_2催化剂(x=3%、4%、5%、6%、7%、8%、9%、10%)上NOx转化率随着WO_3负载量增加而升高,催化剂反应温度窗口不断拓宽。单独通水蒸汽及同时通SO2和水蒸汽对催化剂的毒害作用均较强,表明H2O和NH3的竞争吸附是催化剂抗硫抗水性能较差的重要原因。SO_2与H_2O和NH_3反应生成亚硫酸铵盐和硫酸铵盐,导致催化剂孔隙堵塞,催化活性降低。     

MnOx/Pt/Al2O3 catalysts for CO oxidation in H2-rich streams

The catalytic activity of Pt on alumina catalysts, with and without MnO_x incorporated to the catalyst formulation, for CO oxidation in H₂-free as well as in H₂-rich stream (PROX) has been studied in the temperature range of 25–250 °C. The effect of catalyst preparation (by successive impregnation or by co-impregnation of Mn and Pt) and Mn content in the catalyst performance has been studied. A low Mn content (2 wt.%) has been found not to improve the catalyst activity compared to the base catalyst. However, catalysts prepared by successive impregnation with 8 and 15 wt.% Mn have shown a lower operation temperature for maximum CO conversion than the base catalyst with an enhanced catalyst activity at low temperatures with respect to Pt/Al₂O₃. A maximum CO conversion of 89.8%, with selectivity of 44.9% and CO yield of 40.3% could be reached over a catalyst with 15 wt.% Mn operating at 139 °C and λ = 2. The effect of the presence of 5 vol.% CO₂ and 5 vol.% H₂O in the feedstream on catalysts performance has also been studied and discussed. The presence of CO₂ in the feedstream enhances the catalytic performance of all the studied catalysts at high temperature, whereas the presence of steam inhibits catalysts with higher MnO_x content.     

Influence of CO2 and H2O on NOx storage and reduction on a Pt–Ba/γ-Al2O3 catalyst

In this paper, the effect of CO₂ and H₂O on NO_x storage and reduction over a Pt–Ba/γ-Al₂O₃ (1 wt.% Pt and 30 wt.% Ba) catalyst is shown. The experimental results reveal that in the presence of CO₂ and H₂O, NO_x is stored on BaCO₃ sites only. Moreover, H₂O inhibits the NO oxidation capability of the catalyst and no NO₂ formation is observed. Only 16% of the total barium is utilized in NO storage. The rich phase shows 95% selectivity towards N₂ as well as complete regeneration of stored NO. In the presence of CO₂, NO is oxidized into NO₂ and more NO_x is stored as in the presence of H₂O, resulting in 30% barium utilization. Bulk barium sites are inactive in NO_x trapping in the presence of CO₂·NH₃ formation is seen in the rich phase and the selectivity towards N₂ is 83%. Ba(NO₃)₂ is always completely regenerated during the subsequent rich phase. In the absence of CO₂ and H₂O, both surface and bulk barium sites are active in NO_x storage. As lean/rich cycling proceeds, the selectivity towards N₂ in the rich phase decreases from 82% to 47% and the N balance for successive lean/rich cycles shows incomplete regeneration of the catalyst. This incomplete regeneration along with a 40% decrease in the Pt dispersion and BET surface area, explains the observed decrease in NO_x storage.     

氨气改性的NH3@MIL-53(Cr)吸附CO2和CH4的性能

采取水热法成功合成MIL-53（Cr）晶体,分别应用0.1、1、3 mol·L^-1的氨气对MIL-53（Cr）进行改性,制得系列的NH₃@MIL-53（Cr）-1#,NH₃@MIL-53（Cr）-2#,NH₃@MIL-53（Cr）-3#。实验结果表明：与原始的MIL-53（Cr）晶体相比,尽管制得NH3@MIL-53（Cr）系列材料的比表面积依次减少,但其单位比表面积的CO₂吸附容量大小依次为：NH₃@MIL-53（Cr）-3#>NH₃@MIL-53（Cr）-2#>NH₃@MIL-53（Cr）-1#。表明氨气改性会使得材料表面的碱性增强,从而增强了其对酸性气体CO₂的吸附。此外,改性后的NH₃@MIL-53（Cr）对水蒸气的吸附量明显减少,表明其憎水性能得到改善。较高浓度氨气改性会导致材料的比表面积大幅下降,会引起单位质量吸附剂的吸附容量下降。用1 mol·L^-1浓度的氨气改性得到的NH3@MIL-53（Cr）-2#,不仅对CO₂的吸附容量最大,而且对CH₄的吸附容量明显下降,这将有助于进一步提高改性材料NH3@MIL-53（Cr）-2# 对CO₂/CH₄的吸附选择性。     

Inhibition effect of H2O on V2O5/AC catalyst for catalytic reduction of NO with NH3 at low temperature

The inhibition effect of H₂O on V₂O₅/AC catalyst for NO reduction with NH₃ is studied at temperatures up to 250 °C through TPD, elemental analyses, temperature-programmed surface reaction (TPSR) and FT-IR analyses. The results show that H₂O does not reduce NO and NH₃ adsorption on V₂O₅/AC catalyst surface, but promotes NH₃ adsorption due to increases in Brønsted acid sites. Many kinds of NH₃ forms present on the catalyst surface, but only NH₄⁺ on Brønsted acid sites and a small portion of NH₃ on Lewis acid sites are reactive with NO at 250 °C or below, and most of the NH₃ on Lewis acid sites does not react with NO, regardless the presence of H₂O in the feed gas. H₂O inhibits the SCR reaction between the NH₃ on the Lewis acid sites and NO, and the inhibition effect increases with increasing H₂O content. The inhibition effect is reversible and H₂O does not poison the V₂O₅/AC catalyst.