氧化铝负载氮化镍钼的制备及其加氢精制性能研究

采用程序升温还原法制备氧化铝载体负载的氮化镍钼。采用XRD、BET、H₂-TPR和XPS等表征方法对氮化物的理化性质进行研究;并以噻吩和四氢萘的环己烷溶液为原料,考察氮化物作为加氢催化剂的加氢精制性能。实验结果表明,制备的负载型氮化镍钼中氮化物的晶型为Ni₂Mo₃N;H₂-TPR表明,氮化镍钼表面钝化层的还原温度为200℃~400℃;氮化物表面Mo离子存在Mo⁶⁺、Mo⁴⁺、Mo^δ+离子,Mo^δ+离子占多数。氧化铝负载氮化镍钼具有较好的加氢脱硫初始活性和稳定性;原料中不含硫时,催化剂的加氢脱芳初始活性较好,但加氢脱芳稳定性差,原料中硫的引入加速了催化剂加氢脱芳活性的失活。     

制备参数对β-Mo2N0.78催化剂加氢脱硫活性影响的研究

以N2与H2的混合气为反应气，和三氧化钼进行多段程序升温反应，制得一种β晶型的氮化钼。以噻吩为模型化合物的常压加氢脱硫反应表明，β-Mo2N0.78具有较强的加氢脱硫活性和强的抗硫化性能。同时考察了预还原、反应温度以及氮化末温、升温速率、反应气中N2-H2比及氮化时间等制备参数对β-Mo2N0.78加氢脱硫活性的影响。研究发现，β-Mo2N0.78的加氢脱硫活性在320 ℃～400 ℃随反应温度的升高增强，而还原预处理会降低催化剂的活性。氮化末温、氮化时间、反应气组成和升温速率等制备参数对催化剂的活性有明显的影响：随着氮化末温的升高，所制备的催化剂催化加氢脱硫活性降低；在氮化末温恒温较长时间，可以引起制备催化剂的加氢脱硫活性下降；存在最佳的反应气组成和各段升温速率。小晶粒的β-Mo2N0.78具有强的加氢脱硫活性。     

络合物分解法制备碳氮夹杂钼基催化剂及其催化性能

通过调变六次甲基四胺与金属钼盐的摩尔比例,以络合物分解法制备了碳氮夹杂钼基催化剂,并将其负载于氧化铝载体上．采用X射线衍射（XRD）、X射线光电子能谱（XPS）、低温氮吸附、元素分析等方法对催化剂进行了表征,发现碳氮夹杂钼基催化剂实为碳化钼（β-Mo2C）与碳氮化钼（M02CxNy）的混合物．以二苯并噻吩（DBT）的加氢脱硫反应（HDS）为探针,比较了负载型碳化钼、氮化钼及碳氮夹钼基催化剂的催化活性,发现由于夹杂催化剂中含有新的活性相Mo2CxNy。而表现出高于碳化钼和氮化钼催化剂的催化活性．     

氮、磷、碳化物比较研究初探

环保法规的日益严格使得研究者越来越重视新型加氢脱硫、脱氮催化剂的开发。国内外学者在对负载型Mo—Co、Mo—Ni和W—Ni等传统硫化物催化剂进行不断改进的同时，新型催化材料尤其是具有贵金属性质的过渡金属间充化合物一氮化物、碳化物和磷化物的研究也受到很大的关注。人们在探索不同的载体或者是不同的助剂对单金属间充化合物-氮化物、碳化物或磷化物催化剂活性组分的表面状态和结构以及其深度加氢脱硫脱氮性能的影响，而对同一载体负载的氮、磷、碳化物催化剂缺乏横向的比较。本研究制备了以γ-Al2O3为载体的负载型氮化钼、磷化钼和碳化钼催化剂，比较了它们的孔结构、比表面积，并初步分析了钼的质量分数为19％，氮化、磷化和碳化温度均为650℃时三类催化剂的二苯并噻吩加氢脱硫性能。     

二苯并噻吩在CoMoNx催化剂上的加氢脱硫

以ＭｏＯ３及沉淀法制得的ＣｏＭｏ氧化物为前驱体,在Ｎ２－Ｈ２混合气中用程序升温反应制得一系列氮化（钴）钼催化剂;用二苯并噻吩加氢脱硫为模型反应,考察了催化剂的催化性能。结果表明：⑴二苯并噻吩在氮化钼催化剂上的加氢脱硫有两条反应途径,即噻吩环直接氢解加氢脱硫;苯环先加氢,然后噻吩环氢解脱硫。⑵氮化钼有高的活性和选择Ｃ—Ｓ键断裂生成联苯的选择性,Ｃｏ的加入明显提高了氮化钼的催化活性。⑶不同预处理条件对     

负载β-Mo2N0.78催化剂上加氢脱硫和加氢脱氮反应行为的研究

在N2-H2下，利用程序升温还原氮化反应制备氧化铝负载的β-Mo2N0.78催化剂，并以苯并噻吩（BT）、二苯并噻吩(DBT)和喹啉为模型化合物，考察该催化剂的加氢脱硫、加氢脱氮活性和选择性。实验结果表明，升高反应温度和压力均提高催化剂的加氢脱硫、加氢脱氮活性；升高温度可同时改善DBT的直接脱硫和氢化脱硫，对选择性没有明显的影响；提高反应压力有利于加氢产物的生成；同时可以使联苯加氢转化为环己基苯。添加喹啉的加氢脱硫反应结果表明，含氮化合物的添加降低了催化剂加氢脱硫反应活性，抑制了氢化脱硫反应的发生。少量硫化合物的添加，使喹啉的转化率提高，还提高了脱氮率。     

β－Mo2N0．78的合成及其对噻吩加氢脱硫反应的催化性能

 以N2－H2混合气为反应气，与三氧化钼进行多段程序升温反应制得了氮化钼．考察了反应气组成和氮化温度等条件对氮化钼结构组成的影响．结果表明，在n（N2）／n（H2）＝0．25～1，θ＝650～750℃的条件下，生成的氮化钼结构组成为β－Mo2N0．78．其生成机理与γ－Mo2N有类似之处．β－Mo2N0．78催化噻吩加氢脱硫反应的结果表明，β－Mo2N0．78催化剂对该反应有较高的催化活性，在360℃下，其活性比硫化钼催化剂高一倍左右．     

负载型钼系超细催化剂的合成,结构与反应性能研究

负载型钼系催化剂广泛用于加氢脱硫、抗硫甲烷化及部分氧化等,其加氢脱硫活性与低温氧的表面吸附量成正比,活性组分受载体性质的影响。超细粒子是近年来兴起的新型催化材料,由于其表面及体积效应,导致其特殊的表面吸附性能。以超临界法合成NiO/Al_2O_3、Fe_2O_3/SiO_2等超细催化剂已有报道,但该法对MoO_3/Al_2O_3的合成尚未见报道。本文以MoO_3/Al_2O_3超临界法合成超细粒子催化剂,根据超细催化剂分散性与粒径的关系选择了活性与钼表面分散性有依赖关系的临氢重整反应为探针,研究了超细MoO_3/Al_2O_3催化剂的性质。     

氧化铝负载氮化钼的表面性质与加氢脱氢性能

 研究了氧化铝负载氮化钼的表面性质及加氢脱氢性能．结果表明：负载型氮化钼处于高度分散状态,钝化态氮化钼表面为氮氧化钼或氧修饰的氮化钼,与真正的氮化钼有很大的区别;在苯、环己烯和环己烷的转化反应中,氮化钼对苯无加氢活性,但对环己烯和环己烷具有很高的脱氢活性和一定的裂化活性;钝化态氮化钼具有一定的苯加氢活性和环己烷裂化活性．实验结果表明,氮化钼的加氢／脱氢活性中心为钼,裂化活性中心与氮原子有关．同时,还考察了Ni（Co）Mo氮化物对苯和环己烷的催化裂化性能．     

NiMo 催化剂上MoS2 形貌与其DBT 加氢脱硫选择性的关系

制备了两个系列不同镍钼负载量的NiMo 催化剂,并用X 衍射、N2 物理吸附和透射电镜进行了表征。以二苯并噻吩
为模型硫化物,在高压固定床微型反应器上对该NiMo 催化剂的加氢脱硫性能进行了评价,研究了MoS2 形貌与催化剂加氢脱
硫选择性之间的关系。结果表明,镍钼负载量对MoS2 形貌有明显的影响。Mo18Ni4 催化剂(含18% MoO3 和4% NiO)上
MoS2 呈多级层状结构,具有较高的加氢脱硫活性和优异的加氢脱硫选择性。加氢选择性与催化剂上活性组分MoS2 的堆积层
数相关联呈很好的线性关系;堆积层数越多,其加氢选择性也越高。     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.