MgO-supported cluster catalysts with Pt–Ru interactions prepared from Pt3Ru6(CO)21(μ3-H)(μ-H)3

Bimetallic MgO-supported catalysts were prepared by adsorption of Pt₃Ru₆(CO)₂₁(μ₃-H)(μ-H)₃ on porous MgO. Characterization of the supported clusters by infrared (IR) spectroscopy showed that the adsorbed species were still in the form of metal carbonyls. The supported clusters were decarbonylated by treatment in flowing helium at 300 °C, as shown by IR and extended X-ray absorption fine structure (EXAFS) data, and the resulting supported PtRu clusters were shown by EXAFS spectroscopy to have metal frames that retained Pt–Ru bonds but were slightly restructured relative to those of the precursor; the average cluster size was almost unchanged as a result of the decarbonylation. These are among the smallest reported bimetallic clusters of group-8 metals. The decarbonylated sample catalyzed ethylene hydrogenation with an activity similar to that reported previously for γ-Al₂O₃-supported clusters prepared in nearly the same way and having nearly the same structure. Both samples were also active for n-butane hydrogenolysis, with the MgO-supported catalyst being more active than the γ-Al₂O₃-supported catalyst.     

Preparation and cyclisation reactions of 3-Carboxy-4-naphthylbut-3-enoic Acids

The condensation of naphthalene-1- or 2-carbaldehyde with dimethyl 2,2-dimethyl-succinate (Stobbe conditions) gives predominantly the ( Z )-hemiesters 3 and 11a . The hemiester 3 contains a small amount of the ( E )-isomer. Similar condensation of naphthalene-2-carbaldehyde with dimethyl-2-methylsuccinate gave the hemiester ( E )- 12a . Their configuration and the ratios of the ( Z:E )-hemiesters, their derived acids, anhydrides, indenones and phenanthrene derivatives are inferred by high resolution ¹H-n.m.r. spectroscopy.     

Ru Nanoparticles on Pr2O3 as an Efficient Catalyst for Hydrogen Production from Ammonia Decomposition

Catalysis Letters - Development of efficient catalysts for ammonia decomposition is crucial for hydrogen production from ammonia. Herein, Ru nanoparticles (NPs) highly dispersed on Pr2O3 (Ru/Pr2O3)...     

3-羟基丙醛加氢制1,3-丙二醇的研究

以Ni／Al2O3为催化剂，在固定床反应器上考察了3-羟基丙醛(3-HPA)加氢制1，3-丙二醇(1，3-PDO)的反应工艺条件，结果表明，当反应温度为70℃、反应压力为5．0MPa、氢气与3-羟基丙醛摩尔比为7．0,3-HPA液时空速(IHSV)为6．0h^-1时，3．HPA转化率100％，1，3-PDO选择性大于99％。     

微小通道内液体扰流微孔逸出气泡串的迁移行为

对微小矩形通道内,液体扰流下微孔孔口逸出气泡串的迁移行为进行了可视化实验。基于图像处理方法,分别研究了液体流量和通道倾斜角度对气泡串尺寸、运动速度以及运动轨迹的影响。发现了不同工况下通道内的微气泡堆积现象,并对其进行了分析。结果表明：增大液体流量或者通道倾角,使得形成的气泡尺寸减小,气泡运动轨迹与通道壁面夹角减小,气泡运动速度增大。液体流量与通道倾角影响了通道内微气泡堆积的位置及数量。     

A triheterometallic cluster: synthesis and structural characterisation of a cyclopentadienyl-substituted pentanuclear cluster based on an Os3CoRu metal core

The ionic coupling of the carbonyl cluster anion [Os₃Co(CO)₁₃]⁻ (1) with [Ru(η⁵-C₅H₅)(NCMe)₃]⁺ affords the new pentanuclear triheterometallic cluster Os₃CoRu(CO)₁₃(η⁵-C₅H₅) (2) as well as the known bimetallic cluster compounds HOs₃Ru(CO)₁₁(η⁵-C₅H₅) and Os₃Ru₂(CO)₁₁(η⁵-C₅H₅)₂. The crystal structure of cluster 2 shows that the metal framework is based on a trigonal bipyramid (approximate C_s symmetry) with the Ru, Co and an Os atom occupying the equatorial metal plane.     

Synthesis and characterization of new polyamides derived from 1,3-bis[4-(4-aminophenoxy)phenyl]adamantane

Several new polyamides were synthesized by direct polycondensation of the 1,3-bis[4-(4-aminophenoxy)phenyl]adamantane ( I ) with various dicarboxylic acids. The polyamides had inherent viscosities and number-average molecular weights (M_n) of 0.46–0.96 dL/g and 28,000–109,000, respectively. All polyamides III had good solubilities and were soluble in N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), and pyridine. Polyamides had tensile strengths of up to 72.3 MPa, elongation to breakage values of up to 10.2%, and initial modulus of up to 2.1 GPa. Their glass transition temperatures were found to be 228–269°C and 252–307°C using differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA), respectively. The melting temperature of III_f was observed at 318°C using DSC. The temperatures of polyamides III at a 5% weight loss ranged from 395 to 435°C in air and from 400 to 450°C in a N₂ atmosphere. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68:315–321, 1998     

废钌/氧化铝催化剂中钌的回收研究

采用"碱熔—氧化蒸馏"的方法对钌/氧化铝催化剂中钌的回收进行研究。分别讨论了碱熔剂、碱熔温度、碱熔时间及氧化蒸馏时间等对钌氧化铝催化剂中钌回收率的影响。实验表明,以KOH/KNO3作碱熔剂,650℃下反应2.5 h,NaC lO+H2SO4作氧化剂,80℃减压蒸馏1.5 h,得到三氯化钌盐酸溶液,经减压蒸馏至干涸得到β-RuC l3.3H2O晶体。钌/氧化铝催化剂中钌回收率可达到93%。     

Synthesis of vinyl phenyl acetate and an evaluation of vinyl chloride/vinyl phenyl acetate copolymers

The synthesis of vinyl phenyl acetate, by an ester interchange reaction between phenyl acetic acid and vinyl acetate and utilizing a catalyst, is described. Copolymerization with vinyl chloride, in a suspension system and using a peroxide catalyst, is described on a laboratory and pilot plant scale. Monomer/copolymer compositions, for an initial charge consisting of vinyl chloride/vinyl phenyl acetate (80/20 by weight) are presented over a range of conversions, as an indication of reactivity ratios. Discs, molded from unstabilized copolymers, show very good clarity and color stability, which improve with increased comonomer loading. Some retention of unpolymerized vinyl phenyl acetate monomer occurred, and some increase in softening points resulted following two reprecipitations from acetone into excess methanol. Compound from a 96/4 vinyl chloride/vinyl phenyl acetate copolymer has better color stability than does an equivalent vinyl chloride/vinylidene chloride copolymer compound. The enhanced color and heat stability of the copolymers is attributed to the aromatic character of the comonomer vinyl phenyl acetate.     

Heterogeneous cationic polymerization of 1,3-dioxolane and 1,3-dioxepane using grafted BF3 on silica

Summary A BF₃ complex has been grafted onto silica and used as initiator to polymerize 1,3-dioxolane and 1,3-dioxepane. Grafting the active centers leads to a decrease of the reaction rate. The molecular weight increases steadily, parallel to the monomer conversion and the polydispersity is rapidly stabilized at a low value. MALDI-TOF mass spectrometry analysis shows that most of the polymer chains are initiated by a proton and lost a CH₂O unit. An exchange process between polymer chains bound to the silica and those remaining in the reactional medium was proposed. Finally, a semi-continuous process was investigated by adding continuously dioxolane during a 100 hours period. Received: 21 February 2001/ Revised version: 2 November 2001/ Accepted: 6 November 2001     

Kinetics of aqueous phase hydrogenation of maleic acid to succinic acid over an Ru/Al2O3 catalyst

The kinetics of aqueous phase catalytic hydrogenation of maleic acid to succinic acid were studied in a slurry reactor between 323 and 353 K using a hydrogen partial pressure range of 1.03–2.06 MPa, with a 5% Ru/Al₂O₃ catalyst. The initial rate data were analyzed using a power law model. Above 1.72 MPa hydrogen partial pressure, the reaction was zero order with respect to hydrogen. Based on this hydrogen pressure effect, a Langmuir–Hinshelwood rate model was proposed to which the rate data could be fitted well. Copyright © 2003 Society of Chemical Industry     

间甲酚直接氧化合成间羟基苯甲醛

研究了以间甲酚为原料,采用化学氧化法直接合成间羟基苯甲醛,比较了不同氧化剂的性能,以及反应温度,时间,原料配比和介质对反应的影响,发现以三氧化铬为氧化剂,醋酐为介质,反应温度为０￣１０℃,反应８￣１０ｈ,间羟基苯甲醛的选择性为８６％,收率为７０％。     

丁腈橡胶对三元乙丙橡胶包覆剂抗硝化甘油迁移性能的影响

采用夹层法研究了丁腈橡胶含量对三元乙丙橡胶包覆剂抗硝化甘油迁移性能的影响。结果显示：在三元乙丙橡胶包覆剂中丁腈橡胶的含量不同,其抗硝化甘油迁移性能不同;丁腈橡胶含量为20％～25％时,抗硝化甘油迁移性能最佳。     

胎侧字体模板从AutoCAD到CATIA的迁移

介绍将胎侧字体模板从AutoCAD迁移到CATIA并进行参数化的一种解决方案。通过从AutoCAD中读取字体关键点坐标,按高宽比进行缩放,可以实现字体大小的参数化;通过知识工程的应用,可以实现字体的垂直方向定位和扇形变形等功能;通过特征封装固化已有的字形,可以实现比AutoCAD更强大的模板功能。各种字体集合成字体库,可为胎侧字体图的快速设计提供直接的支持。     

苯磺酸-3-硝基对甲苯酯的合成及晶体结构

以对甲苯酚为原料,超声波辅助下高收率得到苯磺酸对甲苯酯,经硝化合成了标题化合物,用IR、1HNMR、元素分析对其进行表征,X-射线分析数据表明苯磺酸-3-硝基对甲苯酯属于单斜晶系,P2(1)/n空间群.     

甲醇在Pt—Ru／WO3电催化剂上的电化学氧化

通过对Ｐｔ－Ｒｕ／ＷＯ３电极的制备及其催化活性研究。在Ｐｔ／ＷＯ３电极的基础上加入钌元素,能较大地提高低温氧化甲醇的活性和稳定性,是一种有潜力的甲醇直接氧化燃料电池的阳极催化剂。     

纸质食品接触材料中甲醛与残留化学物迁移规律的研究

文章对比分析了2种不同纸包装材料与常温水、热水、4%乙酸在不同温度、不同时间浸泡条件下,包装中甲醛及总物质的迁移规律。研究结果表明,甲醛迁移与化学残留物总迁移量的大小受各种浸泡条件影响是一致的,影响因素大小依次为:介质温度时间。采用乙酰丙酮分光光度比色法测定浸泡液中甲醛含量,该法对甲醛检测线性范围为:0~2 ug/mL,相关系数达到0.9990,检测限量为0.07 ug/mL,回收率达到92%以上。     

Isotopic tracing study of K promotion of NH3 synthesis on Ru

There has been much discussion based on indirect evidence about the site heterogeneity of catalysts for ammonia as well as the effect of alkali promotion. This paper presents the results from direct measurements using steady-state isotopic transient kinetic analysis (SSITKA) of surface site heterogeneity on Ru/SiO₂ induced by K promotion. This heterogeneity is caused by the creation of a set of super active sites. It is the high activity of these sites, more than just the increase in number of surface intermediates, which produces the high activity of K promoted Ru for ammonia synthesis.     

3-芳基-1,3-苯并噁嗪的合成及其生物活性研究

以四氯化锡作催化剂,水杨醛、取代苯胺、硼氢化钠、多聚甲醛为原料合成了4种3-芳基-1,3-苯并噁嗪类化合物,收率为63%~73%(以氨甲基苯酚计,n/n)。产物化学结构经IR、1H NMR、13C NMR、MS和元素分析确证。测定了所合成化合物的杀虫和杀菌活性,结果表明合成化合物具有一定的杀菌活性,如5d在500 mg/L浓度下对稻纹枯病菌的防效为80%,5c在25 mg/L浓度下对油菜菌核病菌的抑制率为78.5%。     

胶塞硅油在输液制剂中的迁移研究

通过不同硅化级别胶塞包装的注射用水制剂和不同型号硅油(二甲基硅油)的模拟注射液,进行注射剂瓶倒置的60℃高温加速试验,研究胶塞硅油在输液制剂中的迁移情况。结果表明:注射用水制剂中的硅油量受胶塞硅化级别和硅油型号的影响;胶塞硅化级别越高,硅油残留量越大,注射用水制剂中不溶性微粒越多,硅油挂壁现象越明显;粘度低的硅油更容易迁移。药企应关注胶塞表面的硅油残留量及其在输液制剂中的迁移性,根据药性选择合适的胶塞。