钼体系催化合成1,2－聚丁二烯的研究

本工作通过较系统地研究Ziegler-Natta型钼催化体系对丁二烯聚合的催化作用，发现一类活性很高的钼催化剂。此类催化剂以无毒，资源丰富的加氢汽油为溶剂，活性已接近工业化的Ni、Co、Ti等体系。同时，本工作又找到了大幅度调节聚合物分子量和链结构的方法，发现了具有活性聚合特点的钼催化体系，初步考察了钼体系催化丁二烯聚合的动力学行为；并利用红外光谱，~(13)C-NRM、X-射线衍射和热分析等方法研究了所得聚合物的链结构和聚集态结构，对聚合物的基本性能也进行了初步考察，发现所得聚合物的一些基本性能超过天然橡胶。此类高活性钼催化剂由MoCl_4OR和(i-Bu)_2AlOAr组成，R为C_(8-18)烷基，Ar为芳基。本催化体系在70 ℃下催化丁二烯聚合时，催化剂用量为Mo/J摩尔比等于4 * 10~(-5)时，转化率可达78％。本体系聚合物分子量可用烯丙基卤等调节，其中烯丙基碘的效果最好。在Mo/J = 8 * 10~(-5)时，烯丙基碘/Mo摩尔比为0.1时即可使聚合物分子量下降约50万；烯丙基碘/Mo摩尔比为10时，聚合物重均分子量即小于20万（不加烯丙基碘为270万）。本体系聚合物分子量分布很窄，聚合温度为30 - 70 ℃时，_W/_n为1.5-2.0；_W/_n与聚合温度呈直线关系，利用外推法估计和动力学考察，本体系在－18 ℃左右有可能引发活性聚合。本体系聚丁二烯含有85％以上1,2－链节，其1，2-链节含量也可以用某些极性添加剂来调节。利用烯丙基碘做调节剂，可制得1,2－链节含量高达98％的聚丁二烯。烯丙基碘还可以调节聚合物链节的立体构型和序列分布；随着烯丙基碘用量的增加，间同1,2－链节增多，全同和无规1,2－链节减少，序列分布的有规性增加，链结构趋于规整。根据动力学初步研究结果，本体系催化丁二烯聚合的速度对单体浓度呈一级关系，表现活化能为17.07千卡／摩卡，催化剂利用率为4％，链增长速度常数为: k_(p30℃) = 40 (升／摩尔·分，下同), k_(p40℃) = 97, k_(p50℃) = 267, k_(p60℃) = 508, k_(p70℃) = 12077。本体系聚合物在烯丙基碘/Mo摩尔比小于2时，无论静态或拉伸下均为无定型；烯丙基碘/Mo摩尔比大于2而小于8时，静态下为无定型，而拉伸时产生结晶，与天然橡胶类似；烯丙基碘／Mo摩尔比大于8时，静态下亦有一定程度的结果。

丙烯选择氧化和氨氧化钼铋催化剂作用机理的研究

为了深入研究丙烯选择氧化和氨氧化剂的作用机理。探索不同金属离子的催化作用，催化剂的结构、性质与活性的关系。我们应用共沉淀方法制备了α－钼酸铋，γ－钼酸铋，Bi_3(FeO_4)(MoD_4)_2土业催化剂Mo_(12)BiFe_3Ni_(2.5)Co_(4.5)Pa_5K_(0.107)O_(55)+50%SiO_2，Bi_3FexM_(0.3-x)O_n催化剂体系，浸Bi钼酸铁体系，M_7~(24)Fe_3BiMo_(12)O_(96)(M~(2+) = Mg, Ni, Co, Cu, Pb, Sr)体系的催化剂。测定了这些催化剂的X射线衍射数据、IR，Raman，ESCA，Mossbauer等，研究了这些催化剂的结构、组成、物理化学性质。同时考察了这些催化剂对丙烯氨氧化的催化作用，并试图把催化剂的性质与催化作用关联起来。同时，为了进一步研究催化剂的表面活性相、活性中心的性质，丙烯氧化和氨氧化中的表面中间体的形式和键合情况。我们使用了丙烯、丙烯醇、氨、丙烯胺作为分子探针，研究了这些分子的程序升温脱附情况，以便了解钼铋催化剂的催化作用。浸Bi钼酸铁研究说明，Bi可能是丙烯α氢脱除的活性中心。Mo-O多面体起丙烯吸附、氧或氮插入活性中心的作用。由于钼酸铁晶格的敞开性和弹性。Bi进入了钼酸铁晶格，形成了Bi嵌钼酸铁的表层结构。成为对丙烯选择氧化的催化剂。钼酸铁由于Fe~(3+)的部分填充d电子结构，是一种使双键断裂，进行深度氧化的催化剂。Bi进入Fe_2(MoO_4)_3表层的缺陷，形成Bi = o-O-Mo = o对，使深度氧化中心变成选择氧化中心。Bi_3Fe_xMo_(3-x)O_n体系中，随着Fe的加入，形成了Mo-Bi-Fe三元化合物。该化合物比Bi_2Mo_2O_9具有更高的活性和选择性。晶格中Fe~(3+)的存在，将促进P型电导，这时Fe~(3+)相当于受主杂质杂质，降低了费米能级。而丙烯的吸附活化形成烯丙基是一给电子过程。因此，Fe~(3+)的存在将加快丙烯活化吸附的速度，也就加速了反应。并且，Fe~(3+)/Fe~(2+)的氧化还原对存在，能快速接受Mo或Bi上的电子，保持Mo和Bi的氧化态，有利于反应的进行。同时，Fe~(2+)具有较低的电负性，能起到提供氧吸附、进行再氧化的中心的作用。把催化剂的电子提供给氧，同时把晶格氧输送到还原位上。这种多功能作用的协合，可能是Mo-Bi-Fe体系高活性和高选择性的原因。丙烯吸附中，所有催化剂都存在可连吸附中心和不可逆吸附中心。丙烯的吸附是活化解离吸附。不同催化剂的丙烯和丙烯醛的脱附情况相似。说明不同催化剂的丙烯吸附中心，丙烯醛或（丙烯腈）生成中心可能是相同的。丙烯醛脱附峰的存在，说明催化剂的晶格氧离子确能与丙烯作用生成丙烯醛。丙烯醇和丙烯胺的脱附说明，都存在可逆吸附和不可逆吸附两种类型。它们在催化剂表面的吸附是活化解离化学吸附，其吸附中心可能与丙烯选择氧化和氨氧化中的丙烯醛（或丙烯腈）生成中心相同。丙烯氧化反应中，烯丙基氧插入形成的Q－O键合物中间体，与丙烯醇解离吸附形成的表面吸附物种（Mo-O-CH_2-CH = CH_2）相同。同样，丙烯胺解离吸附形成的表面物种（Mo-NH-CH_2-CH = CH_2），可能与丙烯氨氧化中烯丙基Q－NH键合而成的中间体相同。这两种中间体，对选择性生成丙烯醛和丙烯腈起决定作用。NH_3的吸附存在两种可逆吸附类型。而不可逆吸附在高温区以N_2和H＿2O脱附出来。NH_3在催化剂的解离吸附形成NH_2基。温度升高继续脱氢形成NH基。该NH基会插入烯丙基，形成（Mo-NH-CH_2-CH = CH_2）中间体，其继续反应形成丙烯腈。

NiCrAlYSi涂层与镍基高温合金基体互扩散行为研究

采用电弧离子镀方法在镍基高温合金DZ125上沉积NiCrAlYSi涂层,通过对不同氧化时间后Al和Cr原子浓度分布曲线的分析,运用Boltzmann-matano方法,计算了Al和Cr元素在1373K分别加热0.5,2h和5h的互扩散系数,并拟合了这三个时间段的计算结果。结果表明:相同温度下,Al和Cr的互扩散系数分别随Al和Cr的原子浓度增加而增大。随氧化时间的延长,Al的互扩散系数随原子浓度的变化先增大然后基本不变,Cr的互扩散系数则逐渐减小;伴随着元素间互扩散行为的增强,涂层中的Al和Cr向基体扩散,基体合金元素Ni,Co,Mo,Ti和W则向涂层扩散,但涂层中Mo和Ti的含量相对较少。由于元素间互扩散行为,涂层中各元素的含量将趋向于更加均匀。

Preparation and Electrical Properties of New Oxide Ion Conductors Ce6-xGdxMoO15-delta (0.0 <= x <= 1.8)

A series of oxide ion conductors Ce6-xGdxMoO15-delta (0.0 <= x <= 1.8) have been prepared by the sol-gel method. Their properties were characterized by differential thermal analysis/thermogravimetry (DTA/TG), X-ray diffraction (XRD), Raman, IR, X-ray photoelectron spectroscopy (XPS), and AC impedance spectroscopy. The XRD patterns showed that the materials were single phase with a cubic fluorite structure. The conductivity of Ce6-xGdxMoO15-delta increases as x increases and reaches the maximum at x = 0.15. The conductivity of Ce4.5Gd1.5MoO15-delta is sigma(t) = 3.6 x 10(-3) S/cm at 700 degrees C, which is higher than that of Ce4.5/6Gd1.5/6O2-delta (sigma(t) = 2.6 x 10(-3) S/cm), and the corresponding activation energy of Ce4.5Gd1.5MoO15-delta (0.92 eV) is lower than that of Ce4.5/6Gd1.5/6O2-delta (1.18 eV).

Synthesis and electrical properties of new solid state. Electrolyte materials Ce5.2RE0.8MoO15-delta

A series of solid state electrolytes, Ce-5.2 RE0.8 MoO15-delta (RE = Y, La, Sm, Gd, Dy, Ho, Er), were synthesized by sol-gel method. Their structures and electrical conductivities were characterized by X-ray Diffraction (XRD), Raman and X-ray Photoelectron Spectroscopy (XPS) and AC impedance spectroscopy, respectively. The results show that the concentrations of oxygen vacancy increased with increasing x and their conductivity were improved. And the cell parameters increase as the radius of RE3+ increases. Because the ionic radius of doped Dy3+ (0.0908 nm) is closed to that of Ce4+ (0.0920 nm), their oxide has minimal cell elastic straining between RE3+ and oxygen vacancy, and the system has the least association enthalpy, thus the oxide Ce-5.2 Dy-0.8 MoO15-delta exhibits a higher conductivity (7.02 x 10(-3) S/cm) and lower activation energy (1.056 eV) compared to the other doped compounds.

Roles of oxygen vacancy and lower valence metallic ion in direct decomposition of NO over La-2-x(Sr,Th)(x)CuO4+/-lambda

Two systems of La2-xSrxCuO4+/-lambda and La2-xThxCuO4+/-lambda, mixed oxides with K2NiF4 structure were synthesized. The compositions and structures of the catalysts were characterized by means of XRD, XPS, chemical analysis and so on. The catalytic behavior for the direct decomposition of NO has been investigated. The results show that the catalytic activity is closely related to the oxygen vacancy and lower valence metallic ion in the direct decomposition of NO. The presence of oxygen vacancy is necessary for mixed oxide to have steady activity in NO decomposition.

3,4－聚异成二烯的合成及所得聚合物结构与性能表征

近二十多年来，在异成二烯的络合催化聚合中，由Ni、Co、Ti及稀土等过渡金属元素络合物组成的催化体系，研究报道得很多，有些已投入工业生产。但由最常见的过渡金属元素铁络合物组成的催化体系，对异成二烯聚的聚合却不多见。本工作研究了三乙酰基丙酮铁为主催化剂，烷基铝为助催化剂，添加含氮类给电子试剂组成三元体系，对异成二烯聚合的催化作用。Fe(a cac)_3 - Al(i-Bu)_3二元体系不能引起异成二烯聚合，而加入少量的含氮类给电子试剂如邻菲啰啉、α,α'－联吡啶等，催化活性显著提高。聚合活性与含氮类给电子试剂的性质有关，并随着下列顺序依次递减：邻菲啰啉、α,α'－联吡啶、对苯二胺、邻苯二胺，对硝基苯胺、邻硝基苯胺；吡啶和已二胺对催化活性的提高几乎没有贡献。烷基铝的不同对催化活性也有明显的影响。其活性顺序为：Al(i-Bu)_3 approx Al Eτ_3 > Al(i-Bu)_2H。首次合成了结晶的3,4－聚异成二烯，3,4－链节含量为70％左右时，Tm为121 ℃左右， Tc为65 ℃左右，透射电镜下观察到结晶的3,4－聚异成二烯具有球晶状结构。初步研究了铁系三元催化体系的反应机理，设想铁化合物和烷基铝生成的烷基铁必须与含氮类给电子试剂作用才能形成活性中心；可见光谱和催化活性实验数据证实了含氮类给电子试剂参与活性中心的形成，并起着稳定活性中心的作用。本文详细地研究了Fe(a cac)_3 - phen - Al(i-Bu)_3催化体系对异成二烯的聚合，考察了起始单体浓度、聚合温度，催化剂总用量以及催化剂各组分配比对聚合速率、聚合物的特性粘数和链节结构的影响，从实验结果讨论了Fe(a cac)_3 - phen - Al(i-Bu)_3体系催化异成二烯的聚合机理，并进行了一些动力学的基本计算，得到了与实验结果基本相符的结果，解释了一些实验现象。铁系聚异成二烯橡胶的表征工作未见诸文献，本工作对铁系聚异成二烯生胶的结晶、力学、流变及阻尼性能作了较系统的研究，并对硫化胶的物理机械性能，弹性及阻尼性能作了初步的表征。铁系聚异成二烯橡胶在室温具有较好的阻尼性能，并且生热值和冲击弹性均较低，可作为室温阻尼材料使用。

A STUDY OF SURFACE OXYGEN SPECIES FROM LA-ME-O (ME=MG, CA, SR, BA) CATALYSTS FOR METHANE OXIDATIVE COUPLING

CO2-TPD was used to study the surface basicity of La-Me-O mixed oxides and O-2-TPD, CH4-TPD were employed to study the surface active oxygen species. Comparing the CO2-TPD with O-2-TPD, we can see that the basicity of catalyst is in parallel with the catalystic activity. The stronger basicity is more profitable for the catalyst to adsorb oxygen to form active oxygen species and to activate CH4 by breaking a C-H bond, By comparing the catalytic activity, the results showed that La-Ba-O(La/Ba=7/3) catalyst had the strongest basicity, and it gave the highest CH4 conversion and C-2 selectivity, The results from the pulse reaction showed that the lattice oxygen participated in the OCM reaction without gas oxygen, and it was the selective oxygen species.

分析痕量元素时水样的的保存

本文评述了天然水样品中PPb级的Cu、Pb、Zn、Cd、Cr~(3+)、Cr~(6+)、Ni、Co、Mn、Fe、As~(3+)、As~(5+)、Se~(4+)、Se~(6+)、Hg、F-的保存条件。如水样的pH值,金属离子的初始浓度,容器的材料,保存的时间和温度等等。建议水样经0.45微米泸膜过泸后。用硝酸酸化至pH≤1.5(As、Se用硫酸酸化),对于Hg不仅酸化,还应加入半胱氨酸、氯金酸或重铬酸钾等保护剂。水样贮存在干净的高密度聚乙烯或聚四氟乙烯(特氟隆)容器中,在4℃的条件下为最佳。

Distribution and mobility of metals in agricultural soils near a copper smelter in South China

The distribution and mobility of heavy metals in the paddy soils surrounding a copper smelting plant in south China was investigated. We assessed the degree of metal contamination using an index of geoaccumulation. The metals were divided into two groups: (1) Cu, Zn, Pb and Cd, whose concentrations were heavily affected by anthropogenic inputs, and (2) Ni, Co and Cr, which were mainly of geochemical origin. Concentrations of Cu, Cd, Zn, and Pb in the polluted soils were higher than the Chinese soil quality criteria. The chemical partitioning patterns of Pb, Zn and Cu indicated that Pb was largely associated with the residual and NH2OH HCl extractable fractions. In contrast, Cd was predominantly associated with the MgCl2 extractable fraction. A large proportion of Cu was bound to the acidic H2O2 extractable fractions, while Zn was predominantly found in the residual phase. The fraction of mobile species, which potentially is the most harmful to the environment, was found to be elevated compared to unpolluted soils in which heavy metals are more strongly bound to the matrix. The mobility of the metals was studied by water extraction using a modification of Tessier's procedure, and the order of mobility was Zn > Cd > Cu > Ce > Pb.

Environmental changes reflected by sedimentary geochemistry in recent hundred years of Jiaozhou Bay, North China

Sediment geochemical technique was employed to assess how the sediment records reflect the environmental changes of Jiaozhou Bay, a semi-enclosed bay adjacent to Qingdao, China. In the past hundred years, Jiaozhou Bay has been greatly impacted by human interventions. A dated core sediment by Pb-210 chronology was analyzed for trace metals including Li, Cd, Cr, Pb, Cu, Ni, Co, Zn together with C, N, P and BSi. Based on the research, the development of Jiaozhou Bay environment in the past hundred years can be divided into three stages: (1) before the 1980s characterized by relatively low sedimentation rate, weak heavy metal pollution and scarce eutrophication; (2) from the 1980s to 2000, accelerating in the 1990s, during which high sedimentation rates, polluted by heavy metals and the frequent occurrence of red tide; (3) after 2000, the period of the improvement of environment, the whole system has been meliorated including the heavy metal pollution and hypernutrification. (c) 2006 Elsevier Ltd. All rights reserved.

青藏高原3种秦艽组植物微量元素比较分析

利用全谱直读等离子体发射光谱法（ICP—AES）测定了3种秦艽组植物10种微量元素（Cu，Zn，Fe，Mn，Ni，Co，Sn，V，Al，Ti）的含量，并进行了比较分析。结果表明，所测定元素在3个不同物种内的含量排列顺序基本一致，显示了三者在元素富集方面的相似性。就同一种元素在3个物种内的富集水平而言，以麻花艽根部具有较高含量的元素Cu，Zn，Co，Al和Ti，管花秦艽根部则大量富集了其余5种微量元素，达乌里秦艽对元素的吸收积累能力居中，揭示了不同物种对同一元素富集能力的差异。该研究可为秦艽类植物资源的深入开发利用提供参考。

青藏高原多年冻土区高寒草甸植物群落主要植物化学元素含量特征

分析了青藏高原北麓河地区29种高寒植物15个元素含量的特征。结果表明，这些植物中元素平均含量〉400μg／g的元素有Ca，Mg，Na，K，Fe，10～100μg／g的有Mn，Cr，Zn，Cu，〈10μg／g的有Ni，Co，As,Pb，Cd，Hg；种间同种元素的含量变化规律不统一。相关性分析表明，Cu与Cd，Fe与Cd和Hg，Cr与Ni，Co和Mg极显著正相关，Cr和Ca极显著负相关；聚类分析表明，Na，As元素对本区植物聚类的影响最大，莎草科、禾本科、菊科科内植物元素含量相似。