镍基催化剂上稻草水蒸气重整制富氢合成气

采用浸渍法制备了SiO₂, γ-Al₂O₃, CaO和TiO₂负载的Ni催化剂, 以及不同MgO含量的MgO-7.5%Ni/γ-Al₂O₃催化剂,利用X射线衍射和N₂吸附-脱附技术表征了催化剂的结构,在固定床反应器上评价了它们在稻草水蒸气催化重整制合成气反应中的催化性能,考察了反应条件对催化剂性能的影响.结果表明, 以γ-Al₂O₃为载体时Ni催化剂活性最高,其中7.5%Ni/γ-Al₂O₃催化剂的H₂收率可达1071.3ml/g,H₂:CO的体积比为1.4:1;同时,MgO的添加进一步提高了该催化剂的性能,当MgO含量为1.0%时,H₂收率可达1194.6ml/g,H₂:CO体积比可达3.9:1.可见MgO的加入促进了Ni基催化剂上稻草水蒸气催化重整制合成气反应的进行,同时使得合成气中CO发生水-汽转换反应,从而大大提高了合成气中H₂含量.     

SO42-/SnO2-Fe2O3固体酸催化下的环酮Baeyer-Villiger氧化反应及缩合反应

采用共沉淀的方法制备了不同Fe 掺杂量的SO₄^2-/SnO₂-Fe₂O₃固体超强酸催化剂. 利用傅里叶变换红外(FTIR)光谱, 粉末X射线衍射(XRD), N₂吸附-脱附实验(BET), 热重(TG)分析和扫描电镜(SEM)等方法对样品进行了表征. 考察了所得催化剂对4-叔丁基环己酮与乙二醇缩合反应的催化性能. 实验结果表明, 与未经过掺杂改性的SO₄^2-/SnO₂固体酸催化剂相比, 改性后催化剂的催化性能得到了改善. 研究了以Fe/Sn 摩尔比为0.5的SO₄^2-/SnO₂-Fe₂O₃固体酸为催化剂, 部分醛酮类化合物与乙二醇及1,2-丙二醇的缩合反应. 考察了反应时间、催化剂用量等因素对反应的影响. 同时, 将所得催化剂应用于环酮Baeyer-Villiger 氧化反应中, 催化剂表现出良好的催化活性, 且催化剂具有一定的循环使用性.     

三种分子筛催化苯胺缩合制二苯胺性能研究

分别以HY,Hβ,HMOR为母体,与拟薄水铝石、铝溶胶混合,采用机械挤出法制备催化剂,采用XRD、N₂等温吸附-脱附（N₂-sorption）、NH₃-TPD、吡啶吸附红外光谱（Py-IR）等分析手段进行表征,探讨了其物化性能的差异,并采用固定床反应器考察了上述催化剂对苯胺缩合制二苯胺反应的催化性能.结果表明,分子筛中强酸对催化剂活性有决定性作用,酸类型对催化性能影响不大;分子筛孔径对二苯胺选择性有显著影响,较小的孔径不利于二苯胺的生成和扩散,降低了目标产物的选择性.因此,在设计和选择苯胺缩合制二苯胺催化剂时应考虑酸性质和孔道尺寸对苯胺转化率和二苯胺选择性的影响来优化催化剂.     

功能化碳纳米管作为固体碱用于Knoevenagel缩合

采用液相沉积方法分别制备了聚乙烯亚胺功能化和聚4-乙烯基吡啶功能化的碳纳米管催化剂,利用N₂吸附/脱附、透射电子显微镜（TEM）、热重分析（TG）以及酸碱滴定等方法对所得催化剂的结构和碱性进行了表征,测试了其对于苯甲醛和丙二腈的Knoevenagel缩合反应的催化性能。结果发现,聚乙烯亚胺功能化的碳纳米管具有比聚4-乙烯基吡啶功能化的催化剂更高的碱催化能力。对碳纳米管进行强酸预处理可增加其与修饰剂的相互作用,虽然会降低其碱催化活性,但却可使其稳定性大大提高。     

四丙基氢氧化铵改性纳米HZSM-5分子筛及其在甲醇制汽油中的催化性能

采用四丙基氢氧化铵(TPAOH)溶液对纳米ZSM-5分子筛进行改性, 运用X射线衍射、扫描电镜、²⁷Al和²⁹Si固体核磁、X射线光电子能谱、N₂物理吸附脱附法和NH₃程序升温脱附等手段对所制样品进行了表征, 并评价了其催化甲醇制汽油反应性能. 结果表明, 改性后的HZSM-5相对结晶度增加, 晶体形貌更加规整, 表面硅铝比增加, 比表面积和微孔表面积增大, 强酸位酸量增多. 同时, TPAOH改性不仅可以使分子筛脱硅脱铝, 而且伴有二次晶化补硅补铝, 改变了分子筛的硅铝分布. 改性的HZSM-5在甲醇制汽油反应中的稳定性大幅度提高, 其寿命由70h增至170h以上, 随着TPAOH处理时间的增加, 催化剂寿命增加, 氢转移反应加快, 导致油相产品中异构烷烃增多, 烯烃减少.     

H2S预处理对Ni2P/SiO2催化剂结构及氯苯加氢脱氯性能的影响

采用10% H₂S/H₂对Ni₂P/SiO₂催化剂进行预处理,利用X射线衍射、电感耦合等离子发射光谱、X射线光电子能谱、CO化学吸附、H₂程序升温脱附、NH₃程序升温脱附及活性评价等方法研究了H₂S预处理对催化剂结构和氯苯加氢脱氯反应性能的影响.结果表明,即使在873K进行H₂S预处理,Ni₂P/SiO₂催化剂体相结构及Ni₂P晶粒大小没有发生变化,但导致Ni₂P晶粒表面形成了磷硫镍相(NiP_xS_y),同时使表面溢流氢数量增加.硫物种的存在不仅阻塞了部分镍中心,使催化剂表面镍中心密度降低,也导致镍中心的缺电子性进一步增加.经H₂S预处理后Ni₂P/SiO₂催化剂上氯苯加氢脱氯反应的转化频率(TOF)明显提高,这可能与催化剂表面Ni物种的缺电子性增强及溢流氢数量增多有关.     

表面助剂改性对Cu/ZnO/Al2O3甲醇合成催化剂性能的影响

采用共沉淀-后浸渍方法制备了表面助剂改性的Cu/ZnO/Al₂O₃ (CZA)甲醇合成催化剂, 在固定床反应器上以合成气为原料分别考察了三种助剂(Zr、Ba和Mn)对CZA催化剂性能的影响; 以Zr为助剂时反应温度的影响; 并进行了催化稳定性试验. 利用粉末X射线衍射(XRD)、低温氮气吸脱附(N₂-sorption)、氧化亚氮(N₂O)反应吸附技术、X射线光电子能谱(XPS)、氢气程序升温吸脱附(H₂-TPD)、扫描电子显微镜(SEM)和高分辨透射电子显微镜(HR-TEM)技术对催化剂进行了表征.结果显示: 以Zr或Ba作为助剂能够明显提高CZA催化剂耐热前后的甲醇时空收率(STY); Mn的引入降低了CZA催化剂的耐热前活性; Zr的引入降低了CZA催化剂最高活性温度点, 增强了CZA催化剂的催化稳定性; 还原态CZA催化剂表面Cu⁰和ZnO都能吸附活化氢气, Cu⁰与ZnO的强相互作用有利于提高催化剂的性能, 耐热后催化剂性能的降低归因于Cu晶粒的长大. 在实验和表征结果基础上,提出了CZA催化剂上合成气制甲醇的“双向同步催化反应历程”.     

制备方法对ZnO-ZrO2催化剂上乙醇转化制异丁烯反应的影响

采用恒pH值共沉淀法和非恒pH值共沉淀法制备了ZnO-ZrO₂混合氧化物催化剂,考察了制备方法对乙醇转化制异丁烯反应的影响,并用低温N₂吸附、X射线衍射、扫描电子显微镜、透射电子显微镜、X射线光电子能谱、拉曼光谱、紫外-可见漫反射光谱、NH₃程序升温脱附和CO₂程序升温脱附对催化剂进行了表征。研究结果表明,相比于非恒pH值共沉淀法制备的ZnO-ZrO₂,恒pH值共沉淀法制备的ZnO-ZrO₂具有较高的比表面积,更多的酸量和碱量,从而表现出更好的乙醇转化制异丁烯催化性能。在450℃和乙醇质量空速0.2 h^-1的反应条件下,两种催化剂的乙醇转化率均为100%,恒pH值共沉淀法制备的催化剂的异丁烯得率为54.9%,明显高于非恒pH值共沉淀法制备的催化剂（45.7%）,并且稳定性也是前者明显高于后者。     

整体式 Cu-ZSM-5 催化剂上 NH3 选择性催化还原 NO 活性

 采用浸渍法制备了一系列不同 Cu 含量的 Cu-ZSM-5 催化剂, 并用于 NH₃ 选择性催化还原 (SCR)NO 反应. 结果表明, 当 Cu 含量为 8%时, Cu-ZSM-5 催化剂的活性最高; 当空速为 30 000 h^–1. , 在 198~440 ^oC 反应时 NO 转化率均高于 80%, 最高可达 97%, 且空速的影响较小. 经快速水热老化后, 该催化剂活性明显优于商用 V 基催化剂. H₂O 和 SO₂ 对 Cu-ZSM-5 催化剂的 SCR 活性有所影响, 但可明显恢复. X 射线衍射和 NH3 程序升温脱附结果表明, 当 Cu-ZSM-5 中 Cu 含量为 8% 时, 进入 ZSM-5 中阳离子位的 Cu 较多, 催化剂的活性较高, 且其表面具有较多的酸中心和酸量, 从而有利于 SCR 反应.     

有机改性对粘土负载镍催化剂的促进作用及其萘加氢性能

以有机改性后的十六烷基三甲基溴化铵柱撑蒙脱石（CTAB-MMT）为载体,采用浸渍法制备了Ni/MMT催化剂. 通过傅里叶红外光谱、X射线衍射、H₂程序升温脱附、N₂物理吸附以及紫外漫散射等物理化学手段对催化剂进行了表征;并结合微型高压反应釜萘加氢反应,评价了催化剂的加氢性能. 结果表明,有机改性显著改善了Ni/MMT催化剂的金属Ni分散度和织构性质,且所制催化剂表现出优异的萘加氢性能,Ni萘转化率达到88.2%,不仅远高于未处理催化剂（13.1%）和Al₂O₃柱撑处理催化剂（24.2%）,而且高于Ni/SBA-15催化剂（68.2%）. 鉴于CTAB有机柱撑体在催化剂还原过程因热解而消除,其对催化剂所起的作用主要发生于浸渍过程,提出了有机改性在浸渍过程对Ni/MMT催化剂的促进作用机制.     

特定碱性MgO纳米晶暴露晶面上铁基催化剂及其费-托合成反应的研究

本研究采用等量浸渍法、化学沉淀法和超声浸渍法合成了一系列具有良好外露晶面的Fe/MgO催化剂。采用X射线粉末衍射、高分辨透射电子显微镜、CO₂程序升温脱附、H₂程序升温还原、X射线光谱学和N₂物理吸附等物理化学方法对催化剂进行了表征。MgO纳米晶载体的碱性会影响费-托合成产物的选择性。在超声浸渍过程中,MgO纳米晶载体的碱性得到了保持。研究结果显示,Fe/MgO催化剂的碱性会提高CO解离速率和产物中烯烃的选择性。此外,相比于MgO（100）晶面,MgO（111）晶面负载铁基催化剂具有更高的活性（TOF）和烯烃选择性。MgO（111）晶面上更有利于CO的吸附,抑制二次加氢反应,提高产物中烯烃的收率。     

A simple strategy to prepare graphene oxide modified by ammonia gas catalysts for Knoevenagel condensation

A facile and simple strategy to prepare ammonia gas-modified graphene oxide (GO) catalysts was successfully established by gas–solid acid–base reaction at room temperature. The catalytic performances of ammonia gas-modified GO samples were examined in Knoevenagel condensation. The samples were characterized by X-ray diffraction, Fourier transform infra-red spectroscopy, X-ray photoelectron spectroscopy, atomic force microscope, NH₃ temperature-programmed desorption and elemental analysis. The results indicated that the excellent performances of the ammonia gas-modified GO samples in Knoevenagel condensation should be ascribed to the formation of ammonium ions (NH₄ ⁺) by the reaction between ammonia gas and the carboxyl groups located on the edge of the GO.     

Analysis of Acidic Properties of Zeolitic and Non-Zeolitic Solid Acid Catalysts Using Temperature-Programmed Desorption of Ammonia

A method of ammonia temperature-programmed desorption (TPD) for analysis of acidic property of a solid was improved by introduction of a water vapor treatment method and development of a theory for calculation of ammonia adsorption heat from the TPD profile. The improved method was applied to various solid acid catalysts to establish relationships between the acidic properties and catalytic performances for various acid-catalyzed reactions. Here, examples of the applications to some important acid catalysts are reviewed. The exact analysis of acidic property of Y zeolite and its change by such modifications as steaming and ethylenediaminetetraacetic acid (EDTA) treatment gave a new interpretation on the generation of alkane (paraffin) cracking activity on an ultra stable Y (USY) zeolite. The surface density and strength of acid sites on WO₃/ZrO₂ and SO₄ ^2–/ZrO₂ catalysts were determined, and their relations with catalytic activities for Friedel–Crafts type alkylation and skeletal isomerization of alkane were found.     

CaO nanoparticles incorporated metal organic framework (NH2-MIL-101) for Knoevenagel condensation reaction

Porous materials based on NH₂-MIL-101(Cr) MOF and their hierarchical acid-base composite with non-precious CaO was successfully prepared using a one-pot scalable hydrothermal approach. The composites were characterized by XRD, FTIR, UV–vis, ¹HNMR, TGA, N₂ adsorption–desorption isotherms, HRTEM and FESEM. The quantitative assessment of the basic sites was performed by benzoic acid titration. The results reveal that there is no remarkable structural alterations in the NH₂-MIL-101(Cr) after incorporation of CaO. Raising the CaO content boosted the strength of and content of Lewis basic sites from 0.31 to 1.34 mmol g^?1 due to the incorporation with CaO (0.04). Knoevenagel condensation reactions were performed as the probe reactions over the CaO/NH₂-MIL-101(Cr) catalysts. Both basic and acidic sites potentially boosted the reaction. Pure NH₂-MIL-101(Cr) display the catalytic conversion in the reaction (11%) which could be attributed weak basic sites on the NH₂-MIL-101(Cr) framework. However, the conversion (%) was potentially increased over NH₂-MIL-101(Cr) loaded with various content of CaO. The highest performance of (99%) conversion was achieved for (0.04) CaO/NH₂-MIL-101(Cr) catalyst. Exceptional conversion above 90% have been obtained for benzaldehyde derivatives both withdrawing and donating electron moieties. The composites can be recycled in four runs with a very small loss in performance. Furthermore, the composites produced tend to be feasible for various catalytic processes, exploring new avenues to produce of novel inorganic and organic composite materials as heterogeneous catalysts.     

分子筛催化剂上甲醇与三聚甲醛缩合制聚甲醛二甲醚

对HY、HZSM-5、Hβ和HMCM-22分子筛催化剂上甲醇与三聚甲醛缩合制聚甲醛二甲醚（PODE_n或DMM_n）的反应性能进行了研究,考察了分子筛种类和酸性对产物分布的影响。结果显示,以酸性分子筛为催化剂,甲醇与三聚甲醛可缩合得到聚甲醛二甲醚。HY分子筛上反应产物主要为短链的甲缩醛（DMM）;HZSM-5和Hβ分子筛上产物以DMM₁~3为主,其柴油添加剂组分DMM₃~8的收率分别为6.40%和13.78%;HMCM-22分子筛为催化剂时,长链的聚合物收率明显增加,其柴油添加剂组分DMM₃~8的收率可以达到29.39%。NH₃-TPD表征结果表明催化剂表面的酸性对产物分布有着明显的影响：表面弱酸位有利于短链产物DMM的生成,而中等强度的表面酸性位则能促进柴油添加组分DMM₃~8的生成。     

分子筛硅／铝比对Cu-ZnO-Al2O3／HMCM-22催化合成二甲醚反应性能的影响

以六亚甲基亚胺为模板剂,采用动态水热晶化法合成了不同硅/铝比的HMCM-22分子筛,并以其为甲醇脱水活性组分与铜基甲醇合成活性组分(Cu-ZnO-Al2O3)组成双功能催化剂,在连续流动加压固定床微型反应器上考察了其对合成气直接制二甲醚反应的催化性能. 结果表明,随着HMCM-22分子筛硅/铝比的增大, CO转化率变化不大,但CO2和烃类副产物的生成量逐渐减少,从而导致目的产物二甲醚的选择性和收率均逐渐升高. 氨程序升温脱附和吡啶吸附红外光谱表征结果表明,随着分子筛硅/铝比的增大, HMCM-22分子筛的酸中心的数量逐渐减少.     

含氮FAU分子筛的制备、表征及碱催化反应性能

利用脱水氮化法制备了含氮HY分子筛,氮化后分子筛的结晶度和比表面积均得到较好保持.由于氮原子的电负性低于氧原子,氮原子取代氧原子进入HY分子筛的骨架,使其Lewis碱性得到增强.利用氨气吸附红外光谱、二氧化碳吸附红外光谱与二氧化碳程序升温脱附方法对氮化前后的分子筛进行表征.结果表明氮化后HY分子筛的L酸中心数量有所降低,B酸中心数量有所增加,同时生成新的碱性中心.由于新碱性中心的引入,含氮HY分子筛在Knoevenagel缩合碱性探针反应中表现出优异的活性.     

Aminated Ordered Mesoporous Carbons: Preparation and Catalytic Performance for Knoevenagel Condensation Reactions

The amine‐ and diamine‐functionalized mesoporous carbons with hexagonal mesostructure have been prepared by a rationally two‐step modification procedure under mild reaction conditions, respectively. The physicochemical properties of the obtained solid basic mesoporous catalysts were characterized by XRD, TEM, N₂ adsorption‐desorption, FT‐IR, EDX and elemental analysis techniques. The results indicated the organic amine groups were successfully introduced inside the channels of mesoporous carbons without destroying the well‐ordered 2D hexagonal mesostructure. A series of Knoevenagel condensation of aldehyde/ketone with active methylene compounds have been carried out over the diamine‐function‐ alized mesoporous carbons, which proved to be efficient heterogeneous basic catalysts and exhibited a similar catalytic activity after sixth cycles. This can be attributed to its hydrophobic framework and hydrophilic diamine groups, which led to amphiphilic properties and offered some advantages for the Knoevenagel condensation reactions.     

Multifunctional periodic mesoporous organosilica supported dual imidazolium ionic liquids as novel and efficient catalysts for heterogeneous Knoevenagel condensation

A type of multifunctional periodic mesoporous organosilica supported dual imidazolium ionic liquids PMO-IL-anion have been designed and prepared, characterized and evaluated as heterogeneous catalysts for the Knoevenagel condensation. The as-fabricated supported ionic liquids show good catalytic performances in the Knoevenagel condensation at room temperature, especially the supported ionic liquids PMO-IL-NTf₂ and PMO-IL-PF₆, based on a synergetic effect between the Lewis-base-type sites of dual functionalized imidazolium ionic liquids and active sites of periodic mesoporous organosilica. The best catalytic performance over PMO-IL-NTf₂ was observed with excellent yields of 93～99% in a short time of 20～30 min. In addition, the heterogeneous catalyst offers simple operation for recovery and the recycling test showed that it could be reused for five times without significant loss of catalytic activity, thus making this process economical and environmental-friendly.