V2O5-WO3/TiO2-ZrO2脱硝催化剂中 ZrO2和 WO3的促进作用：催化性能、形态及反应机理

商业选择性催化还原(SCR)催化剂成分主要有 V2O5, WO3和 TiO2,但适用温度窗口较窄(300?400℃),使得实际操作过程中活性较低.目前,过渡金属广泛应用于催化剂制备中以提高其催化活性.相比于纯 TiO2和 ZrO2载体, TiO2-ZrO2具有较高的热稳定性以及较多的酸位,虽然有关 TiO2-ZrO2为载体的催化剂研究较多,但未与商业催化剂进行对比研究.而针对 NH3-SCR脱硝机理的实验研究也存在一些争议,主要原因归为以下两方面：(1)多数催化剂不同会直接导致催化剂的活性酸位不同;(2)不同 NH3-SCR脱硝催化剂的起活温度不同.同时, NH3和 NO在反应温度的吸附情况仍需要进一步研究.因此,有必要深入探究 NH3-SCR脱硝机理,以解决现行研究中存在的问题.本文首先采用共沉淀法制备摩尔比为1：1的 TiO2-ZrO2固溶体,并分步浸渍不同质量比的 WO3和1%V2O5,最终得到一系列1%V2O5-x%WO3/TiO2-ZrO2.然后通过 X射线衍射(XRD)和比表面积测试(BET)、程序升温还原(TPR)、原位漫反射红外光谱(in situ DRIFTS)研究了 WO3和 ZrO2对催化性能的影响以及 V2O5-WO3/TiO2-ZrO2催化剂的反应机理. N2物理吸附结果表明, WO3的添加使得催化剂孔结构的热稳定性有所提高,同时随着 WO3含量增加催化剂的比表面积逐渐减小,但仍高于 V2O5/TiO2-ZrO2催化剂; ZrO2对催化剂比表面积增大效果比较明显.结合 XRD结果表明, WO3能促进金属氧化物在载体上的分散;相比于 V2O5-WO3/TiO2催化剂, ZrO2有利于活性组分的分散负载.比较系列 V2O5-x%WO3/TiO2-ZrO2的氨吸附情况,发现 WO3的添加增加了 Br?nsted酸的稳定性,其中以9%WO3的效果最显著.催化剂氨吸附中间物种(–NH2)的发现,证实了 WO3添加促进了 NH3的活化,有利于脱硝反应的进行. SCR反应结果显示, V2O5-9%WO3/TiO2-ZrO2催化剂在300–450oC时 NOx转化效率最优,并发现 O2的存在促进了 NOx的转化.采用in situ DRIFTS研究了 V2O5-x%WO3/TiO2-ZrO2催化剂脱硝机理,300和350oC时 NH3, NO, NO + O2吸附情况表明,在真实的反应温度下,脱硝过程中的活性中心为 Lewis酸中心, Br?nsted酸中心的 NH4+极易从催化剂表面脱附,无法吸附在催化剂表面,且与 NH3相比, NO只能以 NO2的形式弱吸附在催化剂表面.因此,该催化剂遵循 Eley-Ridel脱硝机理.而 V2O5-9%WO3/TiO2-ZrO2催化剂具有相对较高的脱硝效率,因此用来着重研究 NH3-SCR机理.在 NH3吸附过程中, NH3(1204,1602,3156,3264,3347 cm?1)和活性中产物 NH2(1550 cm?1)在催化剂表面的吸附(恒温300oC)是稳定的;随后通入 NO + O2时, NH3吸附过程中的所有吸收峰(包括 NH2)均逐渐减小(NH3吸附态与 NO结合后分解为 N2和 H2O),同时出现 H2O的振动峰,这证明了 V2O5-x%WO3/TiO2-ZrO2催化剂的脱硝反应过程.各类气体吸附情况表明, NO在商业催化剂的吸附状态与 V2O5-x%WO3/TiO2-ZrO2催化剂相同;但 NH3吸附结果表明, Br?nsted酸中心和 Lewis酸中心都是催化剂的活性中心; NO + O2的通入使得催化剂表面的 NH3和 NH4+都逐渐消失.这两种催化剂脱硝反应过程差异主要在于催化剂表面活性中心的不同,导致了不同的 NOx脱除路径.通过in situ DRIFTS比较 O2的存在对脱硝反应产生的不同影响来确定 O2的作用.两类催化剂上 O2均参与了 H2O的形成,促进了催化反应的完成;当 O2不存在时, NO的还原受到了极大地抑制,同时也未出现 H2O;两者的脱硝效率大大降低. H2-TPR和 NH3-TPR结果进一步证实 O2的作用主要是氧化 NO及参与催化过程 H2O的形成.     

Synthesis and applications of mesoporous Cu-Zn-Al2O3 catalyst for dehydrogenation of 2-butanol

A series of mesoporous Cu-Zn-Al2O3 materials have been synthesized at ambient temperature and their structure was characterized by XRD, N2 physical adsorption and TPR techniques. Their catalytic applications for the dehydrogenation of 2-butanol to methyl ethyl ketone (MEK) were evaluated in a fixed-bed flow reactor at atmospheric pressure. It is demonstrated from the XRD patterns that both the as-synthesized samples and calcined samples have the typical XRD patterns of meso-structured materials and the results of N2O chemical adsorption showed that Cu was embedded in the framework of the mesoporous materials and homogeneously dispersed in the mesoporous Cu-Zn-Al2O3 materials. The catalytic activity of 2-hntanol dehydrogenation was varied in the order of CZA(10)相似文献   

CuSO_4/TiO_2催化剂在氨选择性催化还原氮氧化物反应中的性能(英文)

氮氧化物(NO_x)是主要的大气污染物之一.氨气选择性催化还原法(NH_3-SCR)是目前去除固定源排放的氮氧化物的最有效方法,被广泛用于燃煤或者生物质的火电厂中.催化剂是NH_3-SCR法的核心,其中V_2O_5-WO_3/TiO_2催化剂是主要的商业SCR催化剂;但是V_2O_5有毒,对环境的影响很大;另外,该催化剂具有较高的SO_2氧化性能.因而研究者一直在探索新型的SCR催化剂.SO_2是燃煤电厂烟气中的典型气体之一,所以抗硫性能是催化剂的一个重要指标.在SCR反应条件下,SO_2和O_2容易与氧化物催化剂发生反应生成稳定性较高的硫酸盐,覆盖在催化剂表面从而引起催化剂失活.但已有研究发现,硫化会提高K中毒后的V_2O_5-WO_3/TiO_2催化剂的活性.并且,短时间的硫化可以明显提高CuO/Al_2O_3的NH_3-SCR活性.硫酸盐催化剂或许具有较低毒性和较高抗硫性能,应该是一种有前景的SCR催化剂.本文以商业纳米TiO_2为载体,采用湿式浸渍法制备了一系列的CuSO_4/TiO_2催化剂.在自制的活性评价装置上测试了样品的NH_3-SCR活性并且在340℃下连续24 h测试了SO_2、水蒸气及两者共同作用对催化剂活性的影响.使用N_2等温吸附-脱附、X射线衍射(XRD)、X射线光电子能谱(XPS)、H_2程序升温还原(H2-TPR)和NH_3程序升温脱附(NH_3-TPD)对催化剂进行了表征.另外,采用原位红外漫反射光谱研究了CuSO_4/TiO_2催化剂上的NH_3-SCR反应过程.N_2等温吸附-脱附结果表明,负载的CuSO_4没有明显改变载体的孔结构.而XRD结果仅显示锐钛矿TiO_2的衍射峰,说明CuSO_4在载体上有较好的分散度或者CuSO_4的含量低于检测限.XPS结果显示,催化剂中的铜主要以Cu~(2+)形式存在,硫主要以SO_4~(2-)形式存在,而氧主要以晶格氧和吸附氧两种形式存在,并且CuSO_4的存在会增加催化剂中吸附氧的含量.H_2-TPR结果表明,随着CuSO_4含量的增加,催化剂的氧化还原能力逐渐增强.NH_3-TPD结果表明,催化剂表面的酸性位数目随着样品中CuSO_4含量的增加而增加.纯TiO_2的NH_3-SCR活性很差,当温度从300℃增加到450℃时,最高NO_x转化率仅为32.7%.但当CuSO_4负载到TiO_2上以后,催化剂活性明显提高.在反应温度高于340℃时,CuSO_4/TiO_2催化剂的NO_x转化率在94%以上,与商业V_2O_5-WO_3/TiO_2催化剂相当,并且其N_2O生成量低于商业催化剂.不过,当温度低于340℃时,CuSO_4/TiO_2催化剂的NO_x转化率明显低于商业催化剂,说明CuSO_4/TiO_2催化剂的活性仍有待改善.连续24 h测试了SO_2、水蒸汽及两者的共同作用对CuSO_4/TiO_2催化剂活性的影响.结果显示,单独的水蒸气会导致活性轻微下降,但SO_2以及两者共同存在时对催化剂的活性基本没有影响.CuSO_4/TiO_2催化剂的NH_3吸附红外光谱表明,催化剂上存在Lewis和Bronsted两种酸性位,但Bronsted酸性位上的NH_4~+稳定性较差,280℃时即基本消失.在高温时,NH_3主要吸附在Lewis酸性位上且CuSO_4/TiO_2催化剂对NO_x的吸附能力较差,红外光谱未检测到NO_x的吸附峰.380℃下,当NO和O_2通入预吸附NH_3的催化剂样品时,属于Lewis酸性位上NH_3的红外峰明显下降,说明Lewis酸性位上吸附的NH_3参与了反应.CuSO_4/TiO_2显示出高的抗硫抗水性能和比较好的NH_3-SCR活性,应该是一种有应用前景的SCR催化剂.CuSO_4可以增加催化剂的酸性位数目和吸附氧量.根据原位红外漫反射结果,CuSO_4/TiO_2上的SCR反应遵循Eley-Rideal机理.气相的NO与吸附在Lewis酸性位上的NH_3反应生成N_2和H_2O或许是主要的反应途径,并且吸附氧可能会促进这个过程.     

NH4]2Mn3(H2O)4[Mo(CN)7]2.4H2O: tuning dimensionality and ferrimagnetic ordering temperature by cation substitution

[NH(4)](2)Mn(3)(H(2)O)(4)[Mo(CN)(7)](2).4H(2)O (1) has been synthesized by slow diffusion of aqueous solutions containing K(4)[Mo(CN)(7)].2H(2)O, [Mn(H(2)O)(6)](NO(3))(2), and (NH(4))NO(3). Compound 1 crystallizes in the monoclinic C2/c space group. The basic motif of the three-dimensional structure consists of a Mo1-Mn1 gridlike sheet parallel to the bc plane. Two of these sheets are connected through CN-Mn2-NC linkages to form a bilayer reminiscent of the K(2)Mn(3)(H(2)O)(6)[Mo(CN)(7)](2).6H(2)O (2) two-dimensional structure. In 1, [NH(4)](+) cations allow these bilayers to be connected through direct Mo1-CN-Mn1 bridges to form a three-dimensional network, whereas in 2, they are isolated by (H(2)O)K(+) cations. As shown by the magnetic measurements, this increase of dimensionality by counterion substitution induces an enhancement of the ferrimagnetic critical temperature from 39 K in 2 to 53 K in 1.     

Controlled synthesis, characterization, and catalytic properties of Mn(2)O(3) and Mn(3)O(4) nanoparticles supported on mesoporous silica SBA-15

A method established in the present study has proven to be effective in the synthesis of Mn(2)O(3) nanocrystals by the thermolysis of manganese(III) acetyl acetonate ([CH(3)COCH=C(O)CH(3)](3)-Mn) and Mn(3)O(4) nanocrystals by the thermolysis of manganese(II) acetyl acetonate ([CH(3)COCH=C(O)-CH(3)](2)Mn) on a mesoporous silica, SBA-15. In particular, Mn(2)O(3) nanocrystals are the first to be reported to be synthesized on SBA-15. The structure, texture, and electronic properties of nanocomposites were studied using various characterization techniques such as N2 physisorption, X-ray diffraction (XRD), laser Raman spectroscopy (LRS), temperature-programmed reduction (TPR), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The results of powder XRD at low angles show that the framework of SBA-15 remains unaffected after generation of the manganese oxide (MnO(x)) nanoparticles, whereas the pore volume and the surface area of SBA-15 dramatically decreased as indicated by N2 adsorption-desorption. TEM images reveal that the pores of SBA-15 are progressively blocked with MnO(x) nanoparticles. The formation of the hausmannite Mn(3)O(4) and bixbyite Mn(2)O(3) structures was clearly confirmed by XRD. The surface structures of MnO(x) were also determined by LRS, XPS, and TPR. The crystalline phases of MnO(x) were identified by LRS with corresponding out-of-plane bending and symmetric stretching vibrations of bridging oxygen species (M-O-M) of both MnO(x) nanoparticles and bulk MnO(x). We also observed the terminal Mn=O bonds corresponding to vibrations at 940 and 974 cm-1 for Mn(3)O(4)/SBA-15 and Mn(2)O(3)/SBA-15, respectively. These results show that the MnO(x) species to be highly dispersed inside the channels of SBA-15. The nanostructure of the particles was further identified by the TPR profiles. Furthermore, the chemical states of the surface manganese (Mn) determined by XPS agreed well with the findings of LRS and XRD. These results suggest that the method developed in the present study resulted in the production of MnO(x) nanoparticles on mesoporous silica SBA-15 by controlling the crystalline phases precisely. The thus-prepared nanocomposites of MnO(x) showed significant catalytic activity toward CO oxidation below 523 K. In particular, the MnO(x) prepared from manganese acetyl acetonate showed a higher catalytic reactivity than that prepared from Mn(NO(3))2.     

La-Ba-Cu复合氧化物在催化消除NO反应中催化性能的研究

合成了具有钙钛石结构的复合氧化物YBa₂Cu₃O₇、LaBa₂Cu₃O₇、LaBaCu₂O₅、La₂BaCu₃O₇和La₄BaCu₅O₁₂.考察了它们对NO分解和NO+CO反应的催化性能.结合化学分析、XRD、TPD和TPR对催化剂的表征结果,探讨了该系列复合氧化物对NO分解和NO+CO反应的催化机理.     

Copper-linked hexaniobate lindqvist clusters-variations on a theme

Four new one-dimensional materials and one dimer complex based on the linkage of [Nb6O19] clusters and [CuLx] (L=ethylenediamine (en), NH3, H2O) assemble under ambient conditions. These phases include the following: Rb4[Cu(en)2(H2O)2]3[(Nb6O19H2)2Cu(en)2].24H2O (1), space group P; [Cu(en)2(H2O)2]2[(Nb6O19H2)Cu(en)2].14H2O (2), space group P; Rb2[Cu(NH3)2(H2O)4][Cu(NH3)4(H2O)2]2{[Nb6O19][Cu(NH3)]2}(2).6H2O (3), space group P; {[Nb6O19][Cu(NH3)2(H2O)]2[Cu(H2O)4]2}.3H2O (4), space group P2/n; and {[Nb6O19][Cu(NH3)2(H2O)]2[Cu(H2O)4]2} (5), space group C2/m. All structures have been solved by single-crystal methods, and compounds 1-5 were characterized by thermogravimetric analysis, Fourier transform IR, chemical analysis, and magnetic measurements. It has been demonstrated that the conformation, charge, and geometry of the [Nb6O19]-[CuLx] chains can be modulated by varying the type and amount of the [CuLx]2+ species. The charge balance is provided by mixed Rb+/[CuLx]2+ or [CuLx]2+ cations only for structures 1-3, whereas 4 and 5 are neutral chains with no counterions. There are weak antiferromagnetic Cu2+-Cu2+ interactions in all phases. Compounds 2-5 represent the first examples in which the [Nb6O19] Lindqvist ion forms extended solids rather than dimers or decorated monomers when reacted with transition-metal, cationic complexes.     

Effects of Carrier on CuO／TiO2 and CuO／Ti0.5Zr0.5O2 Catalysts in the NO＋CO Reaction

Using TiO2 and Ti0.5Zr0.5O2 as carriers, the CuO/TiO2 and CuO/Ti0.5Zr0.5O2 catalysts were prepared by the impregnation method with Cu(NO3)2 as active component. The catalytic activities in NO CO reaction were investigated using a microreactor-GC system, and structure and reducibility of catalysts were characterized by means of physical adsorption, TPR, XRD, NO-TPD technologies. It was found that the activity of CuO/Ti0.5Zr0.5O2 catalyst was higher than that of CuO/TiO2, probably due to the large specific surface area of Ti0.5Zr0.5O2 that played an important role in NO CO reaction.     

高铜含量中孔Cu-Si二元氧化物的合成和表征

采用CTAB(十六烷基三甲基溴化铵)为模板剂,Na₂SiO₃·10H₂O为硅源,Cu(NH₃)₄(NO₃)₂为铜源,在常温下成功地合成出含铜质量分数高达26%,具有中孔结构的硅基氧化铜复合材料.较系统地研究了反应时间、温度、pH值和铜掺入量等对产物性能的影响.用XRD,HRTEM,FTIR,BET,TG-DTA,ICP和XPS等手段对合成产物的结构进行了表征.     

Synthesis and applications of mesoporous Cu-Zn-Al2O3 catalyst for dehydrogenation of 2-butanol

A series of mesoporous Cu-Zn-Al₂O₃ materials have been synthesized at ambient temperature and their structure was characterized by XRD, N₂ physical adsorption and TPR techniques. Their catalytic applications for the dehydrogenation of 2-butanol to methyl ethyl ketone (MEK) were evaluated in a fixed-bed flow reactor at atmospheric pressure. It is demonstrated from the XRD patterns that both the as-synthesized samples and calcined samples have the typical XRD patterns of meso-structured materials and the results of N₂O chemical adsorption showed that Cu was embedded in the framework of the mesoporous materials and homogeneously dispersed in the mesoporous Cu-Zn-Al₂O₃ materials. The catalytic activity of 2-butanol dehydrogenation was varied in the order of CZA(10)<CZA(CP)<CZA(20)<CZA(30); while the selectivity of MEK was increased in the order of CZA(CP)<CZA(10)<CZA(20)<CZA(30).     

Cu-Bi纳米粉体的制备及其可见光光催化性能研究

以Cu（NO3）2、Bi（NO3）3、COfNH）2为原料,聚乙二醇（PEG）为分散剂,采用均匀共沉淀法制备了Cu-Bi催化剂,用X-射线粉末衍射法、能量色散法、透射电镜和紫外－可见漫反射光谱法对催化剂的组成、粒径大小、表面形貌和光学吸收性能进行了详细表征,并以酸性大红和亚甲基蓝为目标降解物,考察了所制备的Cu－Bi催化剂在可见光下的光催化性能。实验结果表明,该催化剂为类球形纳米粉体,粒度均匀,粒径约50nm。在可见光作用下,该催化剂对酸性大红和亚甲基蓝均表现出良好的光催化性能,且在240min前,对酸性大红的降解率要优于亚甲基蓝;240min后则两者的降解效果相近。     

层状复合氧化物La~4BaCu~5~-~xMn~xO~1~2的表征及在催化消除NO中活性的研究

采用柠檬酸配合法合成了结构呈层状ABO~3的La~4BaCu~5O~1~2复合氧化物, 并以它为基体合成了一系列Mn取代Cu的样品(La~4BaCu~5~-~xMn~xO~1~2, x=1-5)并利用XRD, IR进行了结构表征, 结果表明其均为5层的ABO~3结构。利用H~2-TPR考查了掺杂Mn以后样品的氧化还原性能的变化, 发现由于Mn的掺杂使Cu明显的容易还原。还考查了样品对NO+CO反应的催化活性, 结果表明反应的活性中心是Cu离子,但加入适量的Mn离子可以使活性提高。     

Mesoporous silica SBA-15 modified with copper as an efficient NO2 adsorbent at ambient conditions

Copper oxide particles were synthesized by precipitation in sodium hydroxide and dispersed simultaneously in mesoporous SBA-15 silica. The materials were then submitted to thermal treatment under nitrogen at different temperatures. They were tested as novel NO(2) adsorbents in dynamic condition at room temperature. The surface of the initial and exhausted materials was characterized using N(2) adsorption, XRD, TEM, thermal analysis and FT-IR. The addition of Cu(2)O particles leads to a significant increase in the NO(2) adsorption capacity. However, no trend between the NO(2) capacity and the temperature of the thermal treatment of the materials has been observed. The amount of NO released during the NO(2) adsorption was found to be lower on the materials submitted to a low temperature treatment. On these materials, the formation of copper nitrites is favored, whereas on materials treated at higher temperature, copper nitrates are formed as a predominant species. The results suggest that silanol groups of the silica matrix play an important role in NO(2) adsorption and NO retention at room temperature.     

Novel non-hydrolytic synthesis of a V2O5-TiO2 xerogel for the selective catalytic reduction of NOx by ammonia

A vanadia-titania mesoporous xerogel (10.5 wt% V(2)O(5)) was prepared from chloride precursors using a one-step non-hydrolytic sol-gel route and subsequent drying at ambient pressure; after calcination at 773 K for 5 h no crystalline V(2)O(5) was detected and the resulting mixed oxide exhibited remarkable activity in the selective reduction of NO with NH(3).     

Electrophilic nitration of aromatics in ionic liquid solvents.

Potential utility of a series of 1-ethyl-3-methylimidazolium salts [emim][X] with X = OTf-, CF3COO-, and NO3- as well as [HNEtPri2][CF3COO] (protonated Hünig's base) ionic liquids were explored as solvent for electrophilic nitration of aromatics using a variety of nitrating systems, namely NH4NO3/TFAA, isoamyl nitrate/BF3.Et2O, isoamyl nitrate/TfOH, Cu(NO3)/TFAA, and AgNO3/Tf2O. Among these, NH4NO3/TFAA (with [emim][CF3COO], [emim][NO3]) and isoamyl nitrate/BF3.Et2O, isoamyl nitrate/TfOH (with [emim][OTf]) provided the best overall systems both in terms of nitration efficiency and recycling/reuse of the ionic liquids. For [NO2][BF4] nitration, the commonly used ionic liquids [emim][AlCl4] and [emim][Al2Cl7] are unsuitable, as counterion exchange and arene nitration compete. [Emim][BF4] is ring nitrated with [NO2][BF4] producing [NO2-emim][BF4] salt, which is of limited utility due to its increased viscosity. Nitration in ionic liquids is surveyed using a host of aromatic substrates with varied reactivities. The preparative scope of the ionic liquids was also extended. Counterion dependency of the NMR spectra of the [emim][X] liquids can be used to gauge counterion exchange (metathesis) during nitration. Ionic liquid nitration is a useful alternative to classical nitration routes due to easier product isolation and recovery of the ionic liquid solvent, and because it avoids problems associated with neutralization of large quantities of strong acid.     

Dispersion and reactivity of copper catalysts supported on Al2O3-ZrO2

A series of CuO/Al(2)O(3)-ZrO(2) catalysts with Cu loadings varying from 1.0 to 20 wt % were prepared and characterized by X-ray diffraction (XRD), temperature-programmed reduction (TPR), temperature-programmed desorption (TPD) of CO(2) and NH(3), electron spin resonance (ESR), and Brunauer-Emmett-Teller surface area measurements. The dispersion and metal area of copper were determined by the N(2)O decomposition method. XRD results suggest that the copper oxide is present in a highly dispersed amorphous state at copper loadings < 10 wt % and as a crystalline CuO phase at higher Cu loadings. ESR results suggest the presence of two types of copper species on the Al(2)O(3)-ZrO(2) support. TPR results suggest well-dispersed copper oxide species at low Cu loadings and crystalline copper oxide species at high Cu loadings. Well-dispersed copper oxide species were reduced more easily than large copper oxide species by H(2). The results of CO(2) TPD suggest that the basicity of the catalysts was found to increase with an increase of copper loading up to 5.0 wt % and decreases with a further increase of copper loading. The results of NH(3) TPD suggest that the acidity of the catalysts was found to decrease with an increase of copper loading up to 5.0 wt % and increases with a further increase of copper loading. The catalytic properties were evaluated for the vapor-phase dehydrogenation of cyclohexanol to cyclohexanone and correlated with the results of CO(2) TPD measurements and the dispersion of Cu on the Al(2)O(3)-ZrO(2) support.     

Comparative density functional theory study of the binding of ligands to Cu+ and Cu2+: Influence of the coordination and oxidation state

BP86, B3LYP and MP2 methods, generally used to study large systems containing transition metals, were compared for their ability to accuratly evaluate bond dissociation energies of copper complexes. Various [Cu-L]+ and [Cu-L]2+ complexes in which L are small ligands and the higher coordinated complexes, [Cu(NH3)(4)]+ and [Cu(NH3)4]2+ were studied. For monoligated complexes, the BDEs calculated by the three methods differed by 2 to 60 kcal/mol, the larger differences being obtained for [Cu-L]2+ complexes. The BDEs calculated using the B3LYP functional were in general close to the experimental values whereas the BDEs calculated using the BP86 functional were too high and the BDEs calculated using the MP2 were too low. If we rank the whole ligands according to their increased bond strength, the resulting orders obtained with the three methods are different for the [Cu-L]+ complexes, the B3LYP giving the same order as the experimental one. This result indicates that the BDEs of [Cu-L]+ complexes are better modeled using the B3LYP than using the BP86 and MP2 methods. For [Cu-L]2+, B3LYP also gave the most reliable results whereas BP86 gave too large BDEs and MP2 gave too small BDEs. However, symmetries of ground states can be different using DFT and post-Hartree-Fock methods. For [Cu-N2O]2+ the use of the B1LYP provides a better symmetry of the complex than the B3LYP, as has been recently shown in the literature for [Cu-H2O]2+. MP2 led to an incorrect bent structure for [Cu-N2]2+ in contrast to a linear structure obtained with the other methods, including CCSD(T). However, due to the lack of experimental data for [Cu-L]2+ complexes and to contrasted results for the methods, it is not possible to conclude definitely. For the high coordinated complexes [Cu(NH3)4]+ and [Cu(NH3)4]2+, the PBE calculation method was used in addition to the BP86, B3LYP and MP2. The BDE values were very close to each other when there is no change of the oxidation state during the reaction. On the basis of these calculations, the choice of the method was less crucial for high coordinated complexes [Cu(NH3)4]+ and [Cu(NH3)4]2+ so long as the oxidation state remained the same during the reaction. In contrast, when [Cu(NH3)4]2+ is reduced in [Cu(NH3)3]+ and NH3, the BDE calculated using the four methods were markedly different.     

Determination of copper in coal fly ash in the presence of excess titanium by dynamic reaction cell inductively coupled plasma mass spectrometry

Inductively coupled plasma quadrupole mass spectrometry (ICP-QMS) was used for the accurate determination of copper in coal fly ash samples in the presence of excess titanium, using the reaction of Cu(+) ions with NH(3) in the cell. The method eliminated the effect of polyatomic isobaric interferences at m/z 63 and 65 caused by the formation of (47)Ti(16)O(+), (49)Ti(16)O(+) and (47)Ti(18)O(+) on (63)Cu(+) and (65)Cu(+) by detecting Cu(+) as the product cluster ion Cu(NH(3))(2)(+). As the signal of (63)Cu(NH(3))(2)(+) overlapped with that of (97)Mo(+) which existed in the samples, (65)Cu(NH(3))(2)(+) was detected at m/z 99. The effect of the operating conditions of DRC system was studied in order to obtain the best signal to noise ratio for Cu(NH(3))(2)(+) at m/z 99. The formation of Cu(NH(3))(2)(+) was through the clustering reaction Cu(+)+2NH(3)-->Cu(NH(3))(2)(+) which resulted in the separation of analyte from the interfering oxide. The detection limit for Cu(NH(3))(2)(+) was 0.015 ng mL(-1) as Cu. The method was applied to the determination of copper in NIST SRM 1633a and 1633b coal fly ash reference materials. The precision between sample replicates was better than 2.0% and the analysis results were in good agreement with the certified values.     

Nitrosyl induces phosphorous-acid dissociation in ruthenium(II)

The trans-[Ru(NO)(NH(3))(4)(P(OH)(3))]Cl(3) complex was synthesized by reacting [Ru(H(2)O)(NH(3))(5)](2+) with H(3)PO(3) and characterized by spectroscopic ((31)P-NMR, δ = 68 ppm) and spectrophotometric techniques (λ = 525 nm, ε = 20 L mol(-1) cm(-1); λ = 319 nm, ε = 773 L mol(-1) cm(-1); λ = 241 nm, ε = 1385 L mol(-1) cm(-1); ν(NO(+)) = 1879 cm(-1)). A pK(a) of 0.74 was determined from infrared measurements as a function of pH for the reaction: trans-[Ru(NO)(NH(3))(4)(P(OH)(3))](3+) + H(2)O ? trans-[Ru(NO)(NH(3))(4)(P(O(-))(OH)(2))](2+) + H(3)O(+). According to (31)P-NMR, IR, UV-vis, cyclic voltammetry and ab initio calculation data, upon deprotonation, trans-[Ru(NO)(NH(3))(4)(P(OH)(3))](3+) yields the O-bonded linkage isomer trans- [Ru(NO)(NH(3))(4)(OP(OH)(2))](2+), then the trans-[Ru(NO)(NH(3))(4)(OP(H)(OH)(2))](3+) decays to give the final products H(3)PO(3) and trans-[Ru(NO)(NH(3))(4)(H(2)O)](3+). The dissociation of phosphorous acid from the [Ru(NO)(NH(3))(4)](3+) moiety is pH dependent (k(obs) = 2.1 × 10(-4) s(-1) at pH 3.0, 25 °C).     

8-羟基喹啉铜(Ⅱ)功能化SBA-15的制备、表征及催化性质

利用3-氨丙基功能化的介孔SBA-15(APS-SBA-15)作为载体, 通过C—N共价键将8-羟基喹啉铜(Ⅱ)固定到APS-SBA-15孔道中, 制备了8-羟基喹啉铜(Ⅱ)功能化的SBA-15催化剂[Cu(Ⅱ)-Q-APS-SBA-15], 并将其用于以质量分数30%的过氧化氢为氧化剂的苯酚羟化反应中. 结果表明, Cu(Ⅱ)-Q-APS-SBA-15呈现出较高的苯酚转化率和苯二酚选择性.