Catalytic Dehydration of Ethanol to Ethylene on TiO2/4A Zeolite Composite Catalysts

TiO2/4A zeolite composite catalysts were prepared by coating TiO2 on 4A zeolite via liquid phase deposition. The TiO 2/4A zeolite composite catalysts wtih higher surface weak acidity and lower mediate strong acidity exhibit much better catalytic performance on ethanol dehydration to ethylene compared with 4A zeolite. It is suggested that the TiO2 promoter could improve the effective Lewis acidity of composite catalyst which consequently enhanced the catalytic performance.

Upgrading bio-oil over different solid catalysts

Solid acid 40SiO(2)/TiO2-SO42- and solid base 30K(2)CO(3)/Al2O3-NaOH were prepared and compared with catalytic esterification activity according to the model reaction. Upgrading bio-oil by solid acid and solid base catalysts in the conditioned experiment was investigated, in which dynamic viscosities of bio-oil was lowered markedly, although 8 months of aging did not show much viscosity to improve its fluidity and enhance its stability positively. Even the dehydration by 3A molecular sieve still kept the fluidity well. The density of upgraded bio-oil was reduced from 1.24 to 0.96 kg/m(3), and the gross calorific value increased by 50.7 and 51.8%, respectively. The acidity of upgraded bio-oil was alleviated by the solid base catalyst but intensified by the solid acid catalyst for its strong acidification. The results of gas chromatography-mass spectrometry analysis showed that the ester reaction in the bio-oil was promoted by both solid acid and solid base catalysts and that the solid acid catalyst converted volatile and nonvolatile organic acids into esters and raised their amount by 20-fold. Besides the catalytic esterification, the solid acid catalyst carried out the carbonyl addition of alcohol to acetals. Some components of bio-oil undertook the isomerization over the solid base catalyst.

黄土高原旱区长期施肥条件下土壤钾素形态空间分布特征及有效性研究

在黄土高原南部旱地长期肥料定位试验的基础上研究了土壤钾素空间分布特征及其有效性。结果表明:长期施肥后土壤中特殊吸附性钾(SAK)和非特殊吸附性钾(NSAK)储量增加,但水溶性钾(WSK)和非交换性钾(NEK)则有明显的下降,单施N水溶性钾下降了48.24%,单施P下降32.32%,NP配施和NPK配施分别下降10.61%和17.93%,非交换性钾降幅为8.56%~24.91%。增施钾肥可以缓解因长期施肥作物生长所携出的钾素,增加耕层土壤中的水溶性钾、非特殊吸附性钾及特殊吸附性钾。相关分析结果表明,土壤不同形态钾素对速效钾的重要性依次为WSK>NSAK>SAK>NEK,土壤速效钾与水溶性钾、非特殊吸附性钾呈显著相关,与特殊吸附性钾和非交换性钾无显著相关性。

不同年限蔬菜温室土壤基本化学性质比较研究

本文对沈阳市郊大民屯镇不同年限蔬菜温室土壤化学性质进行研究与分析。得到主要结论如下： 蔬菜温室0～20 cm表层土壤有机质、全氮、速效磷、速效钾、铵态氮、硝态氮均处于较高的养分水平，并且随温室使用年限的延长，呈增加的趋势。土壤有酸化的趋势，土壤电导率呈升高态势。土壤有效态Fe、Mn、Cu、Zn含量分别为8.57～60.30 mg kg-1、2.69～22.43 mg kg-1、0.64～7.52 mg kg-1和0.56～9.29 mg kg-1，变异系数为50%左右；随着温室使用年限的增加，土壤有效态Fe、Mn、Cu、Zn含量总体上呈增加的趋势。土壤Ni、Cd的有效含量随种植年限的延长趋于增加，有效Pb呈现出下降的趋势，土壤重金属Cr的有效态含量与种植年限之间没有明显的相关性。 不同年限蔬菜温室土壤剖面有机质、全氮、速效磷及速效钾含量高于相邻的露地菜田土壤，并随种植年限的延长而增加，随土层深度的增加而下降。温室土壤中铵态氮的含量随温室种植年限的变化相对较小，在土壤剖面不同层次中变化也没有明显的规律性。与露地菜田土壤相比，温室土壤中有效态铁、锰含量下降，有效态铜、锌、铅、镍含量增加。0～30 cm土层土壤交换性Ca呈下降的趋势，交换性Mg呈上升的趋势，土壤Ca/Mg比值呈下降的趋势。

模拟酸雨对马尾松菌根影响研究

本实验表明：外生菌根真菌彩色豆马勃、劣味乳菇、丝膜菌对PH的适应范围较广，最适生长BH呈酸性。模拟酸雨对马尾松幼苗菌根的外部形态和内部结构有明显影响。在温室栽培中，模拟酸雨（PH2.0）显著抑制菌根侵染率，在田间实验中，对菌根侵染率有一定的影响。菌根PH和土壤PH值随模拟酸雨PH下降而逐渐降低，接种菌根菌可略提高菌根PH和土壤PH值。菌根真菌过氧化氢酶对培养基中PH的变化不敏感，模拟酸雨对菌根过氧化氢酶活性影响也不明显。但沙培中，模拟酸雨（PH2.0）显著抑制菌根过氧化氢酶活性。模拟酸雨（PH2.0）显著刺激菌根过氧化物酶活性，接种菌根菌可以降低菌根过氧化物酶活性。不同PH的培养基对菌体硝酸还原酶活性有明显影响，而且菌体生长速度与硝酸还原酶活性呈正相关。模拟酸雨（PH2.0）显著抑制菌根硝酸还原酶活性，而接种菌根菌明显提高根系硝酸还原酶活性。菌体酸性磷酸酶活性对培养基中PH变化不敏感，同样菌根酸性磷酸酶活性对模拟酸雨的影响也不明显，但是接种菌根菌可明显提高根系酸性磷酸酶活性。模拟酸雨对马尾松幼苗茎的高生长影响不显著。但是对幼苗茎、根系的干重和侧根总长度有显著抑制作用。轻度酸雨（PH4.5-3.0）对马尾松幼苗生长有促进作用，接种菌可提高幼苗生长。从菌根形态结构和生理活性上看，接种菌根菌可减轻模拟酸雨对马尾松幼苗根系的危害，增强对模拟酸雨的抗性。4dThe result of experiment showed that ectomycorrhizal fungi Pisolithus tinctorins. Lactarius insulsus. Cortinarius russus can be growth in broad PH rang in pure culture, the optimum growth PH is acidity. The external morphology and internal structure of ectomycorrhiza of P. massoniana are affected with simulated acid rain. In greenhouse, simulated acid rain (PH2.0) treatment caused significant decrease in the percent infection, but it's not marked in field. The PH of mycorrhizal and soil are reduced with reducing rainfall PH. These PH are slight higher for inoculation with ectomycorrhizal fungi. Catalase activity of ectomycorrhizal fungus is not sensitive to medium with different PH. Mycorrhiza catalase activiyt is not affected significantly with simulated acid rain, but it's inhibited significantly with simulated acid rain (PH2.0) in the sand culture. Peroxidase atcivity of mycorrhiza is enhanced significantly with simulated acid rain (PH2.0), but it's universally lower for inoculation with ectomycorrhizal fungus. Ectomycorrhizal fungus nitrate reductase activity is affected significantly to medium with differdnt PH, the rates of these fungi growth and nitrate reductase activity is significant correlation. Nitrate reductase activity of mycorrhiza is inhibited significantly with simulated acid rain (PH 2.0), but it's increased significantly for inocnlation with mycorrhizal fungi. Ectomycorrhizal fungas acid phosphatase activity is not affected to medium with different PH, Mycorrhiza acid phosphatase activity is not affected with simulated acid rain too, the acid phosphatase activity of roots inoculated with mycorrhizal fungas is increased significantly. The highest acidity level simulated rain reduced signhficantly root system biomass and the dry weight of stem. Iower acidity level simulated rain can stimulated the growth of P. massoniana, the growth of seedling inocnlated with mycorrhizal fungus can be increased.

氮杂环化合物的绿色合成研究

氮杂环化合物大多数都是具有生理活性的物质，例如喹喔啉化合物与苯二氮卓类化合物，因此研究氮杂环化合物骨架的构建方法具有一定意义。绿色化学的迅速发展迫切要求化学家发展清洁、经济和环境较友好条件下的有机合成方法。其中，水相反应与绿色固体酸催化剂的使用都是实现绿色有机合成的重要途径，它们非常具有潜力，近些年受到了广泛关注。本论文的主要工作是围绕水相及固体酸催化条件下两类具有生物活性的含氮杂环小分子的合成方法而开展的，具体包括以下内容： 1. 研究和探索出了两类绿色固体酸催化剂蒙脱土（Mont. K-10）和杂多酸(H4SiW12O40), 在水相条件下成功合成出喹喔啉化合物的有效方法。两个催化体系都以无毒无公害的水作反应溶剂，实验条件温和，操作安全简便，反应速度快，底物普适性强，产率高，且产物易分离收集。两类固体酸催化剂，对设备腐蚀性小，可回收循环使用，对环境无公害; 蒙脱土催化大部分底物能得到当量产率的产物，硅钨酸催化催化剂负载量小。 2. 实现了无溶剂条件下，以杂多酸（H3PW12O40）作催化剂，高效合成1,5-苯二氮卓衍生物的合成方法。该催化体系具有以下一些优势：实验条件温和，反应速度较快，底物普适性良好，产物易分离收集，反应过程中没有加入其它有机溶剂，绿色环保。 ‘Green Chemistry’ is currently a major issue of modern chemistry. It is widely acknowledged that there is a growing need for more environmentally acceptable processes in the chemical industry. New green catalysts and green reaction media are the important and efficient strategies in green chemistry. New green catalysts include solid acid catalysts, solid base catalysts, metal catalysts not only possess higher activity and selectivity, but also are easily separated from reaction system. Green reaction media include water, supercritical fluids and ionic liquids can not only substitute traditional toxic and harmed organic solvents, but also improve reaction activity and selectivity. Meanwhile water is a promising green reaction medium for use in modern chemistry because it has a number of advantages such as the cheapest solvent available on earth, being non-hazardous and non-toxic to the environment. Solid acids had also attracted much attention for realizing green chemistry due to their unique acidity, high activity and efficiency as organic catalysts. Nitrogen-containing heterocyclic compounds of different ring sizes such as quinoxaline and benzodiazepine are the important pharmacologically active compounds. Due to the wide biological significance of these compounds, the synthesis of these types of compounds have received a great deal of attention. Despite the large availability of methods to construct nitrogen-containing heterocyclic compounds, there is still a strong need to further explore green methods to efficiently and safely synthesize these compounds. Thus, we aim at developing efficient and green methodology for the synthesis of quinoxaline and benzodiazepine carried out under water condition with solid acid catalysts. The contents of this dissertation are listed as the following: 1. We have developed two catalytic systems for the synthesis quinoxaline via the condensation of an aryl 1,2-diamine with a 1,2-diketone compound in the presence of Mont. K-10 or H4SiW12O40 as a catalyst in water solvent. Both of these two methods can be applied to wide range of substrates, tolerating aryl 1,2-diamine/1,2-diketone with the electron donating/drawing substituent. Operational simplicity, the ambient conditions, use of an economically convenient catalyst, use of water as a desirable solvent, high yields and short reaction times are the key features of these two protocols. 2. We developed a convenient and efficient protocol for the synthesis of a variety of 1,5-benzodiazepines in high yields via condensation of aryl o-phenylenediamine derivatives with a variety of ketones using H3PW12O40 as a green recyclable and heterogeneous catalyst under solvent-free condition. The simple experiment procedure combined with ease of recovery and reuse of this catalyst make this procedure quite simple, more convenient and environmentally benign.

Pd/sulfated alumina - a new effective catalyst for the selective catalytic reduction of NO with CH4

Sulfated alumina (SA) is firstly found to be an effective support for Pd catalyst used in the SCR of NO with methane. The sulfation is important to increase support's acidity which is essential for the reduction of NO over Pd catalysts. On consideration of the lower cost and easier availability of SA, we believe that SA is more promising to act as the commercial support for Pd catalyst used in the SCR of NO with methane.

Catalytic performance of MCM-22 zeolite for alkylation of toluene with methanol

MCM-22 zeolite with mid-strong acidity and openings of 10-membered ring channels may obtain a high catalytic activity and selectivity for alkylation of toluene with methanol. The acidic sites, for catalyzing alkylation of toluene with methanol, are weaker than that for catalyzing toluene disproportionation. Compared with silicon as a modifier, modification of MCM-22 with La(NO3)(3) is a promising way to improve the catalytic selectivity of para-xylene. In addition, the experimental results also clearly indicate the characteristics of MCM-22 structure consisting of large intracrystalline cages, some of which may locate on surface of MCM-22. (C) 2004 Elsevier B.V. All rights reserved.

Effects of zirconia phase on the synthesis of higher alcohols over zirconia and modified zirconia

The catalytic performances of ZrO2-based catalysts were evaluated for the synthesis of higher alcohols from synthesis gas. The crystal phase structures were characterized by X-ray diffraction (XRD) and UV Raman. The results indicated that ZrO2 and Pd modified ZrO2 catalysts were effective catalysts in the synthesis of ethanol or isobutanol, and their selectivities basically depended on the crystal phase of ZrO2 surface. The ZrO2 with surface tetragonal crystal phase exhibited a high activity to form ethanol, while the ZrO2 with surface monoclinic crystal phase exhibited a high activity to form isobutanol. Temperature-programmed desorption (TPD) experiment indicated that the high activity of isobutanol formation from synthesis gas over monoclinic zirconia was due probably to the strong Lewis acidity of Zr4+ cations and the strong Lewis basicity of O2- anions of coordinative unsaturated Zr4+-O2- pairs on the surface of monoclinic ZrO2. (C) 2003 Elsevier B.V. All rights reserved.

不同N素形态对落叶松苗木根/土界面pH值及养分有效性的影响

The effect of different nitrogen and phosphorus sources on pH and the availability of mineral nutrients in the root/soil interface of Larix gmelinii seedlings were studied by means of root-mat method. The results showed that the addition of NH~+_4-N decreased the pH in the root/soil interface, while the addition of NO~-_3-N increased the pH in contrast with the control treatment. The sort of the P sources and the distance from the root plane remarkably influenced the changes of pH in the root/soil interface induced by the addition of the nitrogen sources. Compared with the addition of only NH~+_4-N, the extent to which the pH in the root/soil interface decreased was obviously smaller when treated by NH~+_4-N and rock P. When treated with different P sources, the contents of available P in the root/soil interface were affected by the sort of the N sources. When treated with soluble P, the contents of the available P in the root/soil interface obviously increased for the addition of both NH~+_4-N and NO~-_3-N. When treated with rock P, the contents of the available P increased only in the area 0～3 mm from the root plane for NH~+_4-N, whereas the contents of available P in the root/soil interface changed little for NO~-_3-N. The results above showed that the protons excreted by the roots were the main driving force for the solution of the rock P in the root/soil interface. The availability of Fe in the root/soil interface increased as a result of acidity induced by the NH~+_4-N, whereas the availability of Fe in the root/soil interface decreased because of the pH increase induced by the NO_3~-_N. The effect of different N sources on the availability of Fe in the root/soil interface was also affected by the sort of P sources. The concentrations of P、Fe in the leaves remarkably differed when treated by different N、P sources and concentrations of the P、Fe in the root/soil interface were correlated to those in the leaves of the seedlings.

Production of isobutene from n-butane over Pd modified SAPOs and MeAPOs

Pd modified AlPO-11 and SAPO-5, 11, 34 were used in the direct transformation of n-butane to isobutene. The effect of acidity and porous structure on the supported Pd and the catalytic perfori-nance were discussed. For higher isobutene selectivity, some metals, such as Ti, Fe, Mg, Co and Mn, was incorporated into AlPO-11 framework and isobutene selectivity of 34.86% can be obtained over Pd/MnAPO-11. A combined catalyst system was used for a further improvement of the isobutene selectivity.