Ni/La_2O_2CO_3催化剂对山梨醇氢解产物的选择性调控

采用共沉淀法制备了具有协同稳定作用的Ni/La_2O_2CO_3催化剂,用于山梨醇选择性氢解为小分子醇的研究。采用X射线衍射、氢气程序升温还原、CO_2程序升温脱附和扫描电镜对催化剂进行了表征。考察了不同配比Ni、La的加氢位点和碱性调控对山梨醇氢解产物的影响。结果表明,Ni、La摩尔比为2:3时,山梨醇转化率达到98.6%,C_2~C_3多元醇的产率达到43.8%,催化剂经2次反应后对山梨醇的转化率仍高达90%。探究了催化剂从酸性到碱性调变过程中,山梨醇氢解的产物分布,并提出了反应路径。     

载体改性对Ni基催化剂分解四氢呋喃的影响

利用等体积浸渍法制备了不同金属改性载体的Ni/M_xO_y-Al₂O₃（M:Mg、La、Ce）催化剂,以四氢呋喃（THF）为模型化合物,对Ni/M_xO_y-Al₂O₃催化剂催化降解THF制氢活性进行评价。结果表明,添加助剂Ce、La、Mg后,THF转化率分别提高了12.7%、32.8%和31.0%。利用N₂物理吸附、X射线衍射（XRD）和氢气程序升温还原（H₂-TPR）等方法对不同载体的Ni/M_xO_y-Al₂O₃催化剂进行表征。结果表明,La、Ce、Mg的添加减弱了NiO与载体的相互作用,使得催化剂还原温度降低;La、Mg的氧化物高度分散于催化剂表面,但CeO₂-Al₂O₃复合载体在2θ为28.6°和56.3°处出现了CeO...     

甘油氢解用固体超强碱负载的铜催化剂

用浸渍-燃烧法制备了固体超强碱MgO-CaO和MgO-SrO负载的高分散铜基催化剂,并将其用于甘油氢解制备1,2-丙二醇的反应。N₂吸附、X射线衍射、透射电子显微镜、H₂程序升温还原和N₂O氧化吸附及CO₂程序升温脱附等表征实验结果显示:Cu粒子均分散于Cu/MgO-CaO(或者Cu/MgO-SrO)催化剂的表面;与Cu/MgO相比,Cu/MgO-CaO和Cu/MgO-SrO具有更强的碱性,可以加速甘油的转化。上述结果表明,甘油氢解反应中铜催化剂的活性随碱性的增强而增加。     

制备条件对Ni2P/TiO2-Al2O3催化剂加氢脱硫性能的影响

采用溶胶-凝胶法制备了TiO₂-Al₂O₃复合载体, 以柠檬酸为络合剂, 浸渍法制备了负载型Ni₂P/TiO₂-Al₂O₃催化剂前体, 程序升温H₂还原法制备了Ni₂P/TiO₂-Al₂O₃催化剂, 并用 X 射线衍射(XRD)、N₂吸附比表面积(BET)测定技术对催化剂的结构和性质进行了表征, 考察了浸渍方法、Ni/P摩尔比、Ni₂P负载量对其进行的二苯并噻吩(DBT)加氢脱硫(HDS)性能的影响。结果表明, 当Ni/P比低于1:1时, 能得到单一的Ni₂P物相;当Ni/P比为2:1时, 开始出现Ni₃P物相。采用Ni/P比为1:1、Ni₂P负载量为30%、采用共浸渍方法制备的Ni₂P/TiO₂-Al₂O₃催化剂具有最好的活性, 在360℃、3.0MPa、氢油比500 (体积比)、液时体积空速2.0h^-1的条件下反应4h时, 二苯并噻吩转化率为99.5%。     

基于MCM-41的镍基甲烷化催化剂活性与稳定性

采用浸渍法分别以MCM-41,Al₂O₃和SiO₂ 为载体制备了不同镍负载量的甲烷化催化剂,并在连续流动固定床反应装置上对其甲烷化催化活性进行了评价。研究结果表明,与Ni/Al₂O₃和Ni/SiO₂相比,相同镍负载量的Ni/MCM-41催化剂具有更好的催化活性。同时研究了Ni含量对于Ni/MCM-41催化剂催化活性的影响,发现随着Ni含量的增加,CO转化率和CH₄收率逐渐升高,并且在Ni含量大于10%（质量分数）以后趋于稳定。在n（H₂）：n（CO）=3：1、反应压力1.5 MPa、反应温度350℃及质量空速12000 ml·h^-1·g^-1的反应条件下,10%Ni/MCM-41催化剂CH₄选择性达到94.9%,CO转化率接近100%。在100 h催化活性稳定性试验中,10%Ni/MCM-41催化活性无明显下降,表现出良好的催化活性稳定性。采用X射线衍射（XRD）、氮气物理吸附（BET）、热重分析（TG）及氢气程序升温还原（H₂-TPR）等技术手段对催化剂进行了表征,结果表明Ni颗粒大小是影响Ni/MCM-41催化剂催化活性的主要因素。     

不同载体镍基催化剂对1,4-丁炔二醇加氢性能的影响

采用等体积浸渍法将Ni分别负载在USY、ZSM-5、SBA-15、Al₂O₃和SiO₂ 5种载体上制备Ni质量分数为17%的负载型镍基催化剂,以1,4-丁炔二醇(BYD)加氢制1,4-丁二醇(BDO)为探针反应考察其催化性能。通过X射线衍射、N₂吸附-脱附、H₂程序升温还原及NH₃程序升温脱附对催化剂进行表征。结果表明,在不同载体的催化剂作用下,BYD的转化率均可达到99%以上,但BDO的选择性却有很大差异;其他条件相同时,Ni/SBA-15催化剂反应5 h时BDO的选择性达到83.1%,1,4-丁烯二醇(BED)的选择性为16.6%,且2-羟基四氢呋喃(HTHF)的选择性很低,这与Ni/SBA-15具有较大的比表面积和平均孔径、较弱的酸性和良好的活性金属组分镍分散性有关。进而筛选出在低温低压条件下BYD一步加氢制备BDO的镍基催化剂Ni/SBA-15。     

异辛醇胺化合成三异辛胺镍铜基催化剂的研究

采用浸渍法制备了不同镍铜比的镍基催化剂。采用氢气程序升温还原(H₂-TPR)、氨气程序升温脱附(NH₃-TPD)、X射线粉末衍射(XRD)对催化剂进行表征,并考查其催化异辛醇氨化合成三异辛胺的活性。结果表明,还原态催化剂表面检测出明显的Cu衍射峰,Ni的衍射峰较弱,说明Ni物种更为分散。H₂-TPR表征显示,铜的添加促进了镍的还原,使得催化剂表面还原态Ni和Cu物种增多,增加了催化剂加氢、脱氢能力;NH₃-TPD显示,镍对NH₃有更好的吸附活化作用,铜与镍对NH₃形成了协同吸附。Cu_1.5Ni₁/A300催化剂体现出较好的催化活性,胺化反应4 h,异辛醇转化率达82.69%,三异辛胺选择性达到63.28%。     

钯催化TADBIW氢解合成TAIW

利用沉淀-还原法合成了一系列的钯基双金属催化剂,催化四乙酰基二苄基六氮杂异伍兹烷(TADBIW)氢解合成四乙酰基六氮杂异伍兹烷(TAIW)。探究了以SiO₂、Al₂O₃、TiO₂为载体,Fe、Co、Ni等金属助剂和催化剂用量对产物TAIW收率的影响。结果表明,在50℃、0.5 MPa H₂,以10%Pd-Ni/TiO₂为催化剂,催化剂用量为4%,催化TADBIW氢解反应,产物TAIW收率达91%。采用XRD、XPS、ICP、TEM等手段表征了Pd-Ni/TiO₂催化剂的结构和形貌。将产物TAIW进一步硝化合成CL-20,产物CL-20收率达90%。     

CeO2-Al2O3复合载体负载Ni基催化剂催化COx共甲烷化性能

通过浸渍沉淀法分别制备Ni/Al₂O₃、Ni/CeO₂和Ni/CeO₂-Al₂O₃催化剂，并对其分别进行不同CO/CO₂比例下COx共甲烷化性能评价。发现Ni/Al₂O₃催化剂催化CO转化为CH4的能力明显高于Ni/CeO₂，而催化CO₂甲烷化的性能则相反。采用Ni/CeO₂-Al₂O₃催化剂，可以在提高CO转化率的同时而不降低CO₂转化率。结合BET、XRD、TPR、TPD和原位红外等各种表征手段，发现CeO₂掺杂虽然降低了催化剂的比表面积和金属Ni的分散度，但却可明显提高其吸附活化CO₂的能力，这主要是由于具有较高含量氧空位的CeO₂的掺杂可以提高载体表面碱性位，促使共甲烷过程中CO_...     

载体表面羟基种类对DMO加氢用Cu/SiO2催化剂性能的影响

通过程序升温焙烧改变气相纳米二氧化硅表面的羟基含量及种类,并以其为载体,采用蒸氨法制备了Cu/SiO₂催化剂,使用比表面积测试（BET）、傅里叶变换红外光谱（FTIR）、漫反射傅里叶变换红外光谱（DRIFT）、X射线衍射（XRD）、透射电子显微镜（TEM）、H₂程序升温还原（H₂-TPR）、NH₃/CO₂程序升温脱附（NH₃/CO₂-TPD）、X射线光电子能谱（XPS）、俄歇电子能谱（AES）等方法研究了Cu/SiO₂催化剂的结构和酸碱性,采用固定床反应器在低温（448K）、低压（1.5MPa）的反应条件下进行草酸二甲酯加氢制备乙二醇的反应,评价其催化活性。结果表明,高温焙烧二氧化硅载体可显著改变后续合成Cu/SiO₂催化剂的结构并降低其酸碱性,对提高乙二醇选择性和降低草酸二甲酯加氢过程中醇类或醚类副产物的选择性具有明显的促进作用。但同时该过程会导致催化剂的活性降低,载体焙烧（473K）后合成的催化剂均需要提高氢酯比方能获得最佳反应结果。其中经873K焙烧的二氧化硅制备的Cu/SiO₂-4催化剂,在最佳反应条件下乙二醇的选择性由低温焙烧后的92%左右提升到97%以上,草酸二甲酯转化率保持在100%。     

Tri-reforming of methane: a novel concept for catalytic production of industrially useful synthesis gas with desired H2/CO ratios

A novel process concept called tri-reforming of methane has been proposed in our laboratory using CO₂ in the flue gases from fossil fuel-based power plants without CO₂ separation [C. Song, Chemical Innovation 31 (2001) 21–26]. The proposed tri-reforming process is a synergetic combination of CO₂ reforming, steam reforming, and partial oxidation of methane in a single reactor for effective production of industrially useful synthesis gas (syngas). Both experimental testing and computational analysis show that tri-reforming can not only produce synthesis gas (CO + H₂) with desired H₂/CO ratios (1.5–2.0), but also could eliminate carbon formation which is usually a serious problem in the CO₂ reforming of methane. These two advantages have been demonstrated by tri-reforming of CH₄ in a fixed-bed flow reactor at 850 °C with supported nickel catalysts. Over 95% CH₄ conversion and about 80% CO₂ conversion can be achieved in tri-reforming over Ni catalysts supported on an oxide substrate. The type and nature of catalysts have a significant impact on CO₂ conversion in the presence of H₂O and O₂ in tri-reforming in the temperature range of 700–850 °C. Among all the catalysts tested for tri-reforming, their ability to enhance the conversion of CO₂ follows the order of Ni/MgO > Ni/MgO/CeZrO > Ni/CeO₂ ≈ Ni/ZrO₂ ≈ Ni/Al₂O₃ > Ni/CeZrO. The higher CO₂ conversion over Ni/MgO and Ni/MgO/CeZrO in tri-reforming may be related to the interaction of CO₂ with MgO and more interface between Ni and MgO resulting from the formation of NiO/MgO solid solution. Results of catalytic performance tests over Ni/MgO/CeZrO catalysts at 850 °C and 1 atm with different feed compositions confirm the predicted equilibrium conversions based on the thermodynamic analysis for tri-reforming of methane. Kinetics of tri-reforming were also examined. The reaction orders with respect to partial pressures of CO₂ and H₂O are different over Ni/MgO, Ni/MgO/CeZrO, and Ni/Al₂O₃ catalysts for tri-reforming.     

Si含量对CO_2加氢制烃铁基催化剂的影响

以湿固相研磨法制备不同硅含量的铁基催化剂,采用X射线衍射、H2程序升温还原和傅里叶红外光谱对催化剂进行表征,在V(H_2)∶V(CO_2)∶V(N_2)=16∶8∶1、反应压力1.6 MPa、反应温度230℃、反应时间48 h和空速6 000 m L·(h·g-cat)-1条件下,在固定床反应器中考察催化剂的CO_2加氢制烃反应活性和烃类选择性。结果表明,随着Si O_2掺入量增加,催化剂的还原性能降低,结晶度呈下降趋势,CO_2转化率下降,但C5+烃类产物选择性在硅含量为10%时达到最大,为38.6%。     

酸改性CoPd/TiO2催化CH4-CO2直接合成C2含氧化合物

采用酸处理方法对CoPd/TiO₂催化剂进行改性,并将酸改性催化剂用于温和条件下CH₄-CO₂梯阶转化直接合成C₂含氧化合物（乙酸和乙醇）的反应。在150～300℃考察了浸酸方式和不同种类酸处理对催化剂活性和选择性的影响。采用X射线衍射（XRD）、X射线光电子能谱（XPS）、NH₃程序升温脱附（NH₃-TPD）和N₂吸附对催化剂进行了表征。结果表明,酸改性明显提高了CoPd/TiO₂上C₂含氧化合物的生成速率和选择性。浸酸方式对催化剂性能和结构有显著影响,先用酸浸渍载体然后再浸渍活性金属所得催化剂具有更高的活性。在H₃PO₄、HNO₃和HCl中,H₃PO₄浸渍的催化剂活性最佳,在150℃时C₂含氧化合物（乙酸和乙醇）的生成速率为3365 μg/(g·h),选择性达到91%。     

Highly dispersed nickel boosts catalysis by Cu/SiO2 in the hydrogenation of CO2-derived ethylene carbonate to methanol and ethylene glycol

The efficient hydrogenation of CO₂-derived ethylene carbonate (EC) to yield methanol (MeOH) and ethylene glycol (EG) is a key process for indirect conversion of CO₂ to MeOH. However, a high H₂/EC molar ratio during the hydrogenation process (usually as 180–300) is generally required to achieve good catalytic performance, resulting in high cost and energy consumption for H₂ circulation in the promising industrial application. Here, we prepared a series of Ni-modified Cu/SiO₂ catalysts and explored the effects of synthesis methods and Ni contents on catalytic performance under different H₂/EC molar ratios. The Cu/SiO₂ catalyst with 0.2% (mass) Ni loading prepared by co-ammonia evaporation method exhibited above 99% conversion of EC, 91% and 98% selectivity to MeOH and EG respectively at H₂/EC ratio of 60. And no significant deactivation was observed within 140 h at a lower H₂/EC of 40. It is demonstrated that a few of Ni addition could not only promote Cu dispersion and increase surface Cu⁺ species due to the strong interaction between Cu and Ni species, but also form uniformly-dispersed CuNi alloy species and thus enhance the adsorption and dissociation of H₂. But the excess Ni species would aggregate and segregate to cover partial surface of Cu nanoparticles, leading to a significantly drop of catalytic performance in EC hydrogenation. These insights may provide guidance for further design of catalysts for the ester hydrogenation reactions.     

Ni-W2C催化葡萄糖氢解制备低碳二元醇反应机理研究

采用HPLC、LC-MS、GC-MS等分析手段对不同工艺条件下Ni/W₂C催化葡萄糖加氢转化的中间产物及终产物进行定性定量分析，研究了葡萄糖加氢转化过程的反应机制和历程。研究发现：葡萄糖加氢转化过程中同时平行发生了加氢、异构和逆向羟醛缩合（氢解）三类反应；葡萄糖发生加氢反应能够得到六元醇且其不会再进一步转化，发生逆向羟醛缩合反应主要生成乙二醇（C₂产物），发生异构反应则可生成果糖，其进行逆向羟醛缩合的产物则为1,2-丙二醇和甘油（C₃产物）；高浓度葡萄糖条件下，其异构产物果糖发生脱水反应生成的5-HMF浓度过高发生聚合，进而导致结焦。根据葡萄糖加氢转化的反应网络，提出了调控反应过程中C₂产物和C₃产物分布的策略，并通过增加催化剂用量来加快果糖脱水的竞争反应速率(加氢、氢解)，进而实现了高浓度（10%，质量分数）葡萄糖的加氢转化。此外，葡萄糖加氢转化过程中存在明显的浓度效应，反应物浓度越低，越有利于发生逆向羟醛缩合反应，反之则有利于发生加氢反应。     

Catalytic combustion of natural gas as the role of on-site heat supply in rapid catalytic CO2---H2O reforming of methane

Development in highly active catalysts for the reforming of methane with H₂O, CO₂, and H₂O+CO₂, and partial oxidation of methane was conducted to produce hydrogen with high reaction rates. A Ni-based three-component catalyst such as Ni---La₂O₃---Ru or Ni---Ce₂O₃---Pt supported on alumina wash-coated ceramic fiber in a plate shape was very suitable for both reactions. The catalyst composition was set at 10 wt.-% Ni, 5.6 wt.-% La₂0₃, and 0.57 wt.-% Ru for example, or molar ratios of these components were 1:0.2:0.03. Even with such a low concentration, the precious metal enhanced the reaction rate markedly, and this synergistic effect was ascribed to the hydrogen spillover effect through the part of precious metal and it resulted in a more reduced surface of the main catalyst component. In particular, a marked enhancement in the reaction rate of CO₂-reforming of methane was observed by the modification of a low concentration Rh to the Ni---Ce₂0₃---Pt catalyst. Very high space-time yields of H₂ (i.e., 8300 mol/1 h in partial oxidation of methane at 600°C with a methane conversion of 37.5%, and 3585 mol/1 h in CO₂reforming of methane at 600°C with a methane conversion of 58%) were realized in those reactions. By combining the catalytic combustion reaction, methane conversion to syngas was markedly enhanced, and even with a very short contact time (10 ms) the conversion of methane increased more than that at 50 ms. The space-time yield of hydrogen amounted to 2,780 mol/1 h with a methane conversion of 90% at 700°C. Furthermore, in a reaction of CH₄---CO₂---H₂O---O₂ on the four components catalyst, an extraordinarily high space-time yield of hydrogen, 12 190 mol/1 h, could be realized under the conditions of very high space velocity (5 ms).     

ZSM-5催化剂与低温等离子体协同转化H2S-CO2制合成气

将H₂S和CO₂混合酸气一步转化制合成气,既实现了二者无害化处理,又生产出合成气,是一条理想的废气资源化利用新路线。由于分子结构稳定,在常规条件下因受热力学平衡限制,二者转化率极低。而在低温等离子体中,H₂S和CO₂可被激发为高活性物种来参与反应。研究了具有不同Si/Al摩尔比的ZSM-5催化剂与低温等离子体结合实现H₂S-CO₂一步高选择性制合成气,显著提高了H₂S-CO₂转化性能。考察了ZSM-5催化剂中Si/Al比和低温等离子体放电条件等对反应的影响。其中,当Si/Al比为80时表现出最优催化性能,最高H₂和CO产率分别达到56.1%和10.0%。对常规条件和低温等离子体氛围下的不同ZSM-5催化剂上CO₂、H₂S、CO、H₂等化学吸脱附行为进行了对比研究,发现低温等离子体促进了催化剂对CO₂、H₂及CO分子的吸附活化,进而明显提升了H₂S和CO₂转化。     

ZrOCl_2-H_2SO_4/γ-Al_2O_3催化剂的制备及对1-丁烯齐聚反应的催化性能

以γ-Al_2O_3为载体,负载Zr OCl_2和H_2SO_4制备Zr OCl_2-H_2SO_4/γ-Al_2O_3催化剂,并用于1-丁烯齐聚反应。采用气相色谱在线分析,确定产物组成,考察制备条件对催化剂催化活性的影响,通过1-丁烯转化率和主产物选择性确定适宜的反应条件。结果表明,在Zr OCl_2和H_2SO_4负载质量分数为4.5%和焙烧温度500℃条件下制备的催化剂,在反应温度140℃、1-丁烯液时空速2 h-1和N2分压1.4 MPa条件下,表现出较好的催化活性,1-丁烯转化率96.77%,产物以二聚体(C8)为主,选择性85.99%。该催化剂失活后容易再生,且催化活性良好,1-丁烯转化率92.73%,C8选择性86.73%。     

A comparative study of coprecipitated BaCO3/La2On(CO3)rn catalysts for the oxidative coupling of methane

Coprecipitated catalyst systems containing BaCO₃ and La₂O_n(CO₃)_m (n≥1.5) with La/Ba = 0.05-10 were tested for catalytic activity, selectivity and stability in the oxidative coupling of methane reaction (OCM). Maximum C₂⁺ selectivities of 78% and C₂⁺ yields of 11% were obtained. The results show that La is the more active cation component of the system. The presence of BaCO₃ in the system leads to decreasing crystal size of the La phases, and to higher C₂⁺ selectivities at equal methane conversions. Life time tests showed that the Ba- La-containing catalysts were quite stable. Na impurities in the system lead to larger crystals in the La phases, and to less selective and less stable catalysts for the OCM reaction. Na is lost during reaction.     

蛇纹石与绿矾耦合提取富镁溶液矿化二氧化碳并回收镍

蛇纹石与绿矾耦合提取镁用于矿化二氧化碳,并富集回收蛇纹石中的镍,这为处理蛇纹石和绿矾提供了一条新的路径。为得到富镁溶液,同时从溶液中分离镍,以蛇纹石与绿矾混合焙烧-浸出后得到的溶液为研究对象,采用水解沉淀法除铁,二乙基二硫代氨基甲酸钠(DDTC)络合法分离镍镁,得到镍的产物和富镁溶液并将其用于二氧化碳矿化。结果表明,该方法能够高效地去除杂质、分离镍镁。在30℃、p H为5.0条件下,铁的去除率达97.36%,而镍、镁的损失率较低。在最佳络合条件下,镍的络合率达到99.50%,而镁的损失率仅为3.03%。此外,对络合机理进行了研究,DDTC中的特征官能团是—SH,络合之后镍和铁分别以Ni[(C₂H₅)₂NCS₂]₂,Fe[(C₂H₅)₂NCS₂]₃的形式存在,而镁不会被络合。富镁溶液在80℃下矿化率达92.63%。每1 000 kg蛇纹石可固定227.38 kg的二氧化碳...