H_2-induced CO adsorption and dissociation over Co/Al_2O_3 catalyst

The activation of adsorbed CO is an important step in CO hydrogenation. The results from TPSR of pre-adsorbed CO with H2 and syngas suggested that the presence of H2 increased the amount of CO adsorption and accelerated CO dissociation. The H2 was adsorbed first, and activated to form H＊ over metal sites, then reacted with carbonaceous species. The oxygen species for CO2 formation in the presence of hydrogen was mostly OH^＊, which reacted with adsorbed CO subsequently via CO^＊＋OH^＊ → CO2^＊＋H^＊; however, the direct CO dissociation was not excluded in CO hydrogenation. The dissociation of C-O bond in the presence of H2 proceeded by a concerted mechanism, which assisted the Boudourd reaction of adsorbed CO on the surface via CO^＊＋2H^＊ → CH^＊＋OH^＊. The formation of the surface species （CH） from adsorbed CO proceeded as indicated with the participation of surface hydrogen, was favored in the initial step of the Fischer-Tropsch synthesis.

Evaluation of H2 Influence on the Evolution Mechanism of NOx Storage and Reduction over Pt–Ba–Ce/c-Al2O3 Catalysts

In this investigation, Pt–Ba–Ce/c-Al2O3 catalysts were prepared by incipient wetness impregnation and experiments were performed to evaluate the influence of H2 on the evolution mechanism of nitrogen oxides (NOx) storage and reduction (NSR). The physical and chemical properties of the Pt–Ba–Ce/c- Al2O3 catalysts were studied using a combination of characterization techniques, which showed that PtOx, CeO2, and BaCO3, whose peaks were observed in X-ray diffraction (XRD) spectra, dispersed well on the c-Al2O3, as shown by transmission electron microscope (TEM), and that the difference between Ce3+ and Ce4+, as detected by X-ray photoelectron spectroscopy (XPS), facilitated the migration of active oxygen over the catalyst. In the process of a complete NSR experiment, the NOx storage capability was greatly enhanced in the temperature range of 250–350℃, and reached a maximum value of 315.3μmol·gcat^-1 at 350℃, which was ascribed to the increase in NO2 yield. In a lean and rich cycling experiment, the results showed that NOx storage efficiency and conversion were increased when the time of H2 exposure (i.e., 30, 45, and 60 s) was extended. The maximum NOx conversion of the catalyst reached 83.5% when the duration of the lean and rich phases was 240 and 60 s, respectively. The results revealed that increasing the content of H2 by an appropriate amount was favorable to the NSR mechanism due to increased decomposition of nitrate or nitrite, and the refreshing of trapping sites for the next cycle of NSR.

Oxidative Desulfurization of DBT with H2O2 over 3DOM H3PW12O40/Al2O3 Catalyst

A series of heteropoly acid (HPA) based Al2O3 catalysts with three-dimensional ordered (3DOM) structure were synthesized by colloidal crystal template method.Interconnected macropores (250 nm) could be clearly observed by scanning electron microscope (SEM) and transmission electron microscope (TEM).Mesopores could be detected by N2 adsorption-desorption isotherms which further confirmed the 3DOM structural characteristics of catalyst.Moreover,Keggin-type HPW was highly dispersed in the Al2O3 framework,which suggested by powder X-ray diffraction (XRD) and Fourier transform infrared spectra (FT-IR) results.The oxidation desulfurization (ODS) performance of 3DOM H3PW12O40/Al2O3 of refractory sulphur compounds was evaluated in the presence of hydrogen peroxide.It oxidized 98.5% of dibenzothiophene (DBT) into corresponding sulfone within 3 h,which exhibited superior ODS performance than corresponding mesoporous and microporous H3PW12O40/Al2O3 catalyst.The enhancement of ODS efficiency is related to the improvement of mass transfer of DBT in the pore channel resulting from the interconnected 3DOM structure.Furthermore,the as-prepared catalyst still demonstrates outstanding cycle performance after 6 runs,which could be easily recovered from the model fuel.

OC-3H催化剂脱除氧气中较高浓度甲烷杂质实验及其在氪氙提取中的工业应用

本文介绍了大连凯特利催化工程技术有限公司生产的OC-3H型催化剂脱除氧气中较高浓度甲烷的实验及其在氪氙提取装置中的应用情况。相关实验及应用证明,OC-3H高效氧化催化剂是一种高活性催化剂,可用于脱除氧气中较高浓度甲烷杂质,具有脱除深度深(0.5×10^(-6)V/V)以及操作温度范围广等优点。OC-3H催化剂成功应用在氪氙提取装置中脱除高浓度甲烷,为相关企业创造了良好的经济效益。

Effects of pretreatment and reduction on the Co/Al_2O_3 catalyst for CO hydrogenation

The purpose of this study was to investigate the effect of preadsorbed CO at different temperatures, calcination temperatures, the combined influence of reduction temperature and time, and pretreatment using hydrogen or syngas as reduction agents on the F-T synthesis （FTS） activity and selectivity of Co/Al2O3 catalyst. The reactivity of the carbon species at higher preadsorption temperature with H2 in TPSR decreased, whereas the carbon-containing species showed higher reactivity over Co/Al2O3 catalyst with low calcination temperature. This agreed well with the order of catalytic activity for F-T synthesis on this catalyst. The catalytic activity of the catalyst varied with reduction temperature and time remarkably. CODEX optimization gave an optimum reduction temperature of 756 K and reduction time of 6.2 h and estimated C5＋ yield perfectly. The pretreatment of Co/Al2O3 catalyst with different reduction agents （hydrogen or syngas） showed important influences on the catalytic performance. A high CO conversion and C5＋ yield were obtained on the catalyst reduced by hydrogen, whereas methane selectivity on the catalyst reduced by syngas was much higher than that on the catalyst reduced by hydrogen.

Metathesis of Butylene-2 and Ethylene to Propylene over 3.0Mo/(Hβ+γ-Al_(2)O_(3))Catalysts with Differentγ-Al_(2)O_(3)Contents

A series of 3.0Mo/(Hβ+γ-Al_(2)O_(3))samples withγ-Al_(2)O_(3)contents in the range of 0_100%(mass fraction)was studied by means of XRD,NH_(3)-TPD,TPR and BET determinations for characterizing their structures.The Hβzeolite structure in the 3.0Mo/Hβsample can be effectively stabilized by adding someγ-Al_(2)O_(3)to Hβzeolite.γ-Al_(2)O_(3)mainly favors the formation of polymolybdate or multilayered Mo oxide,while Hβmainly forms the Al_(2)(MoO_(4))_(3)species,as evaluated by the TPR technique.When used as the catalyst for the metathesis of butylene-2 and ethylene to propylene,there exists a close correlation between the specific surface area and stability of the catalyst.The specific surface area of the catalyst shows the maximum when{(Hβ+}γ-Al_(2)O_(3))contains 30%γ-Al_(2)O_(3),which is in agreement with that of the time needed for the reaction stablization.In the case of maximum surface area,the rate of coke deposition is the minimum.

H_2S分压对1-十二烯在NiMo/Al_2O_3催化剂上加氢反应的影响

在加氢裂化反应过程中 ,裂化产生的痕量烯烃会与H2 S结合生成硫醇。为研究H2 S对烯烃加氢及硫醇生成的影响 ,实验室采用微反以正 -十二烯为模型化合物 ,考察了H2 S存在下 1-十二烯在NiMo Al2 O3催化剂上的加氢反应。结果表明 ,在一定范围内H2 S分压的变化对 1-十二烯的转化率没有明显影响 ,但对产品中异构烯烃的选择性有很大影响 ,并直接影响产物中十二碳硫醇的收率与分布。

Renewable hydrogen production from steam reforming of glycerol(SRG)over ceria-modified Y-alumina supported Ni catalyst

Excess crude glycerol derived as a by-product from biodiesel industry prompts the need to valorise glycerol to value-added chemicals.In this context,catalytic steam reforming of glycerol(SRG) was proposed as a promising and sustainable alternative for producing renewable hydrogen(H2).Herein,the development of nickel(Ni) supported on ceria-modified mesoporous γ-alumina(γ-Al2 O3) catalysts and their applications in catalytic SRG(at550-750℃ atmospheric pressure and weight hourly space velocity,WHSV,of 44,122 ml·g^-1·h^-1(STP)) is presented.Properties of the developed catalysts were characterised using many technique s.The findings show that ceria modification improved Ni dispersion on γ-Al2 O3 catalyst support with highly active small Ni particles,which led to a remarkable catalytic performance with the total glycerol conversion(ca.99%),glycerol conversion into gaseous products(ca.77%) and H2 yield(ca.62%).The formation rate for H2 production(14.4 ×10^(-5)mol·s^-1·g^-1, TOF(H2)=3412 s^-1) was significantly improved with the Ni@12 Ce-Al2 O3 catalyst,representing nearly a 2-fold increase compared with that of the conventional Ni@AI2 O3 catalyst.In addition,the developed catalyst also exhibited comparatively high stability(for 12 h) and coke resistance ability.

Glycerol-Based Carbon-SO₃H Catalyzed Benign Synthetic Protocol for the Acetylation of Alcohols, Phenols and Amines under Solvent-Free Conditions

A simple and efficient solvent-free method was developed for the acetylation of alcohols, phenols and amines in excellent yields employing glycerol-based sulfonic acid (-SO3H) functionalized carbon catalyst under environmentally benign reaction conditions. The salient features of this protocol are the short reaction time, ease of product isolation and reusability of the carbon catalyst.

CrCl_3掺杂对钒钛基SCR催化剂脱硝活性的影响

采用等体积浸渍法制备了不同浓度的CrCl_3钒钛基商业催化剂,利用XRD、BET、XPS、H_2-TPR、NH_3-TPD等多种表征手段对催化剂进行了表征,结果表明,Cr在TiO_2载体表面处于高度分散状态,呈无定形相形式;反应温度200~500℃内,含铬催化剂的最高脱硝效率提高7%,在低温时随Cr/V摩尔比的增大而提高,在高温时有较宽的稳定反应窗口;BET结果表明Cr的添加明显提高了催化剂的比表面积、总孔容和孔结构参数;负载铬盐后脱硝催化剂表面弱酸性位的活性中心数目和密度随着含铬量的增大而增大;商业催化剂中钒元素主要以V^(4+)价态存在,随着Cr/V摩尔比的增大,催化剂中V^(4+)所占比例下降而V^(5+)所占比例升高;负载铬化物后铬元素主要以Cr^(3+)价态存在。

5H-10,11-二氢二苯骈(b,f)氮杂的催化脱氢研究

对５Ｈ－１０，１１－二氢二苯骈（ｂ，ｆ）氮杂艹卓的催化脱氢工艺进行了研究，并探讨了催化剂用量。

Sulfamic acid as a reusable and green catalyst for efficient and simple synthesis of 2-substituted-2,3-dihydroquinazolin-4(1H)-ones in water or methanol

A series of 2,3-dihydroquinazolin-4（1H）-ones have been synthesized in good to excellent yields through direct cyclocondensation of anthranilamide and aryl aldehydes or ketones in water or methanol under mild conditions.The reaction was efficiently promoted by 10 mol%sulfamic acid（SA,H_2NSO_3H） and the catalyst could be recovered easily after the reactions and reused without evident loss of reactivity.

催化氧化净化黄磷尾气中的磷和硫

利用黄磷尾气生产甲酸、乙酸以及甲醇等高附加值产品,净化预处理成为制约其应用的瓶颈问题。研究了用普通活性炭和自制催化剂KU2催化氧化净化黄磷尾气的方法;讨论了固定床系统中常压下、温度2 0～14 0℃,催化剂上磷和硫化氢的吸附特征。KU2和活性炭都能通过催化氧化过程有效脱除黄磷尾气中的P4,PH3和H2 S杂质,随着反应温度和氧含量增加可显著提高净化效果,在最优条件下,经催化氧化净化后的总磷含量<5mg/m3 ,硫化氢含量<5mg/m3 ,失效后的催化剂易于再生,催化剂经多次再生后催化性能恢复良好;提出了活性炭固定床稳定流动吸附过程的数学模型,测得了总传质系数,从实验和理论计算两方面分析讨论了该体系吸附过程的动力行为,模型计算结果与实验测定的穿透曲线吻合良好。

甲烷部分氧化铑基催化剂的活性中心本质研究

采用脉冲反应技术，研究了ＣＨ４、ＣＨ４／Ｏ２（２／１）在还原态和氧化态铑基催化剂上的反应情况。观察到，在第一个ＣＨ４／Ｏ２（２／１）脉冲反应点中，氧化态催化剂上的甲烷转化率、ＣＯ２选择性显著高于还原态催化剂；从第二个脉冲反应点开始，氧化态催化剂上的甲烷转化率、产物选择性均与还原态催化剂上的基本接近，表明在第一个ＣＨ４／Ｏ２（２／１）脉冲反应点中，氧化态催化剂中的铑氧化物已被甲烷还原至金属态铑；从第二个脉冲反应点开始，ＣＨ４＋Ｏ２反应实际上在还原态的铑位上进行。由此推断。

光致变色液晶萘并吡喃的合成及光致变色性质

在相转移催化剂C18H37N(CH3)3C l的存在下合成了6-十二烷基-2-萘酚;6-十二烷基-2-萘酚分别与3种炔醇进行缩合,得到了3种萘环上有柔性长链的萘并吡喃:8-十二烷基-3,3-二苯基-3H-萘并[2,1-b]吡喃(NP1)、8-十二烷基-3,3-二(4,4′-甲氧基)苯基-3H-萘并[2,1-b]吡喃(NP2)、8-十二烷基-3,3-二(4,4′-甲氧基)苯基-3H-萘并[2,1-b]吡喃(NP3),对它们在溶液中和高分子膜中光致变色性能进行了研究。利用POM与DSC对其液晶性进行了研究,发现NP1和NP3具有液晶性质。

分子筛催化剂上催化裂化汽油掺混甲醇的改质研究

以实现甲醇制取低碳烯烃转化工艺和FCC汽油降烯烃工艺的有效组合为目的,在固定床微型反应装置上,使用SAPO-34、ZSM-5、DOCO以及分子筛组合催化剂,对FCC汽油掺混甲醇改质进行了研究。主要对反应温度、空速和混炼比等影响因素进行了考察。结果表明,SAPO-34分子筛上甲醇制取低碳烯烃效果较好,高烯烃含量汽油在SAPO-34分子筛上的氢转移和芳构化效果显著,ZSM-5分子筛上的芳构化反应效果和DOCO的异构化反应效果较显著,甲醇转化与汽油转化反应间的相互协同作用,既有利于甲醇转化成低碳烯烃又能提高汽油降烯烃转化深度。适宜的混炼条件:反应温度400℃,m(甲醇):m(汽油)=0.05,空速3h^(-1),组合催化剂上,产物汽油中烯烃含量较FCC粗汽油下降23%以上。

色满衍生物的不对称合成

含有色满环(2H-1-苯骈吡喃-3,4-二氢)结构的天然产物有抗氧化,抗病毒,免疫,强壮神经等功能。合成这类中间体结构,很早就为人们所关注。早期根据生源合成理论,将异戊二烯和酚反应,在路易斯酸存在下合成出色满衍生物。此后在这方面作过许多工作。

尿素装置CO_2脱氢催化剂的再生及其工业应用实例

对尿素装置失活CO2脱氢催化剂的研究表明,无论是以煤、天然气还是以渣油为原料的尿素厂,硫都是导致脱氢催化剂失活的主要原因。结合工业应用实例,介绍硫中毒失活的TH-3脱氢催化剂经过再生处理后,可恢复到接近新鲜脱氢催化剂的活性,完全能够满足工业生产的要求,从而节省装置的运行费用。

regeneration of thermally deactivated commercial V-W-Ti catalysts

An effective method for the regeneration of thermally deactivated commercial monolith SCR catalysts was investigated. Two types of regenerated solutions, namely NH4C1 （l mol/L） and dilute H2SO4 （0.5 tool/L）, were employed to treat the used catalyst. The effects of temperature and the regeneration process on the structural and textural properties of the catalysts were determined by X-ray diffraction, scanning electron microscopy, N2 adsorption/desorption, elemental analysis and Fourier transform infrared spectroscopy. The results suggest that the anatase phase of the used catalyst is maintained after exposure to high temperatures. Some of the catalytic activity was restored after regeneration. The catalyst regenerated by aqueous NH4C1 had a higher activity than that of the catalyst treated by dilute H2SO4. The main reason is that the NH3 generated from the decomposition of NH4C1 at high temperatures can be adsorbed onto the catalyst which promotes the reaction. The aggregated V205 were partially re-dispersed during the regeneration process, and the intrinsic oxidation of ammonia with high concentrations of O2 is a factorthat suppresses the catalytic activity.

Pincer iridium(Ⅲ)-catalyzed enantioselective C(sp3)-H functionalization via carbenoid C–H insertion of 3-diazooxindoles with 1,4-cyclohexadiene

The asymmetric carbenoid C–H insertion of 3-diazooxindoles into 1,4-cyclohexadiene has been accomplished in the presence of chiral bis(imidazoline) NCN pincer iridium(Ⅲ) complexes as the catalysts. With a catalyst loading of 0.5 mol%, the reactions proceeded smoothly at 0℃ to afford a variety of chiral 3-substituted oxindoles in good yields with moderate to excellent enantioselectivities(up to 99% ee). The protocol exhibits good functional group tolerance with respect to 3-diazooxindoles and is readily scaled up to 2 mmol scale without any loss in activity and enantioselectivity. Density functional theory(DFT)calculations have been performed to better understand the reaction mechanism and to explain the stereochemical outcome of the reactions.