镁改性HZSM-5对Cu-ZnO-Al2O3/HZSM-5催化合成气直接制二甲醚反应的影响

 采用浸渍法制备了一系列MgO改性的HZSM-5分子筛,并以MgO/HZSM-5为甲醇脱水催化剂与Cu-ZnO-Al2O3甲醇合成催化剂组成双功能催化剂,在连续流动加压固定床反应器上考察了其对合成气直接制二甲醚反应的催化性能. 结果表明,以适量MgO改性的HZSM-5分子筛组成的双功能催化剂上,二甲醚选择性可高达64.8%,CO2和烃类副产物的选择性分别为30.2%和0.4%; 由未改性的HZSM-5分子筛组成的双功能催化剂上,二甲醚选择性仅为49.1%,CO2和烃类副产物的选择性则分别高达37.1%和9.3%. 当MgO含量过高时,则CO转化率和二甲醚选择性均降低. 根据实验结果,提出了甲醇在MgO/HZSM-5上脱水的反应机理.     

含有多级孔复合分子筛的复合催化剂上合成气一步制二甲醚

以Beta分子筛为核、Y型分子筛为壳层的多级孔复合分子筛(BFZ)作为甲醇脱水催化剂用于固定床中合成气一步法制备二甲醚,并与纯Y型分子筛进行了比较,研究了二甲醚合成催化反应活性与甲醇脱水催化剂孔道结构和酸性之间的关系.结果表明,复合分子筛HBFZ具有中等强度的酸性和中孔孔道结构,有利于提高合成气制备二甲醚的催化反应活性.二甲醚直接合成催化剂由工业CuO/ZnO/Al₂O₃催化剂(CZA)与分子筛(HBFZ、HY)采用机械混合方法制备;催化评价结果显示,CZA/HBFZ比CZA/HY具有更优的催化活性和稳定性.在250 ℃, 5.0 MPa 和 1 500 h^-1的反应条件下,CZA/HBFZ催化剂上CO的转化率和DME的选择性分别达到94.2%和67.9%.     

甲醇及合成气制二甲醚中不同粒径的 HY 分子筛及复合 Cu-Mn-Zn/HY 催化剂

 通过改变导向剂的老化时间, 制备了一系列不同粒径的 HY 分子筛作为脱水催化剂, 考察了甲醇脱水反应性能; 将其与铜基甲醇合成活性组分 Cu-Zn-Mn 组成双功能催化剂, 考察了催化剂对合成气直接制二甲醚反应的催化性能. 结果表明, 粒径为 820 nm 的 HY 分子筛在甲醇脱水中表现出较高的催化活性; 以其作为脱水组分的双功能 Cu-Zn-Mn/HY 催化剂也表现出较高的催化活性和良好的稳定性.     

氧化铝的改性及其在合成气直接制二甲醚反应中的应用

 采用浸渍法制备了经硼、磷和硫的含氧酸根阴离子改性的γ-Al2O3, 以其为甲醇脱水活性组分,与铜基甲醇合成活性组分CuO-ZnO-Al2O3组成双功能催化剂,并在连续流动加压固定床反应器上考察了催化剂对合成气直接制二甲醚反应的催化性能. 结果表明, SO2-4改性可以显著提高γ-Al2O3的甲醇脱水活性,从而提高产物中二甲醚的选择性和一氧化碳的转化率. 此外,还详细研究了SO2-4改性条件如SO2-4含量、焙烧温度及前驱物种类的影响. 结果表明,当SO2-4含量为10%, 焙烧温度为550 ℃时,二甲醚的选择性及一氧化碳的转化率最高; SO2-4前驱物的种类对其改性效果的影响很小.     

合成气一步法制备二甲醚核壳结构催化剂的制备及其反应性能

以生物质(葡萄糖、蔗糖、淀粉)为模板剂,通过水热合成法制备具有核壳结构的CuO-ZnO-Al₂O₃@Al₂O₃复合催化剂,该催化剂以甲醇合成催化剂CuO-ZnO-Al₂O₃为核,甲醇脱水催化剂Al₂O₃为壳.SEM-EDS对催化剂核壳结构的表征发现,通过改变水热合成温度和合成时间可以调变催化剂中Al₂O₃壳层的厚度.将该复合催化剂用于合成气直接制备二甲醚的反应,在空速1 500 mL/(h·g_cat)、温度260 ℃、压力5.0 MPa的条件下,CO转化率和二甲醚选择性分别达到35.2%和61.1%.     

镁改性HZSM-5对Cu-ZnO-Al2O3／HZSM5-催化合成气直接N-甲醚反应的影响

采用浸渍法制备了一系列MgO改性的HZSM-5分子筛，并以MgO/HZSM-5为甲醇脱水催化剂与Cu—ZnO-Al2O3甲醇合成催化剂组成双功能催化剂，在连续流动加压固定床反应器上考察了其对合成气直接制二甲醚反应的催化性能．结果表明，以适量MgO改性的HZSM-5分子筛组成的双功能催化剂上，二甲醚选择性可高达64.8％，CO2和烃类副产物的选择性分别为30．2％和0．4％；由未改性的HZSM-5分子筛组成的双功能催化剂上，二甲醚选择性仅为49．1％，CO2和烃类副产物的选择性则分别高达37．1％和9．3％．当MgO含量过高时，则CO转化率和二甲醚选择性均降低．根据实验结果，提出了甲醇在MgO／HZSM-5上脱水的反应机理．     

CO2加氢制备二甲醚CuO-ZnO-Al2O3/HZSM-5催化剂的研究

以无水乙醇为溶剂,草酸为沉淀剂,采用悬浮共沉淀法,一步合成CuO-ZnO-Al2O3/HZSM-5双功能催化剂.并研究了该催化剂在CO2加氢合成二甲醚反应中的催化性能,考察了CO2加氢合成甲醇组分(CuO-ZnO-Al2O3)与甲醇脱水组分(HZSM-5)配比对催化剂性能的影响以及催化剂的稳定性.结果表明,双功能催化剂加氢与脱水组分配比为8∶1时,对CO2加氢直接合成二甲醚有较高的催化性能:在固定床反应器中,温度为270℃,压力为3.0 MPa,空速为4 800 h-1的反应条件下,CO2的单程转化率达到29.8%,二甲醚的选择性和收率分别达到53.8%和16%.XRD、BET、TPR和NH3-TPD对催化剂结构表征结果表明,不同组分配比影响双功能复合催化剂中脱水组分的酸性和加氢组分的结晶度、晶粒尺寸、CuO的还原性.     

浆态床中合成气制二甲醚宏观动力学的研究(英文)

以液体石蜡为介质,在合成甲醇催化剂与甲醇脱水催化剂比例为5、催化剂浓度为10 g/300 mL液体石蜡,温度为250℃~280℃,压力为3 MPa~5 MPa,气体空速为4 000 mL/(g(h)~7 000 mL/(g(h)的条件下,建立了浆态床合成气制二甲醚宏观动力学模型。甲醇合成反应和甲醇脱水反应的活化能分别为14.06 kJ/mol和23.53 kJ/mol。甲醇当量生成速率和二甲醚生成速率的计算值与实验值的相对误差在10%和20%以内。     

H4SiW12O40-La2O3/γ-- Al2O3催化甲醇脱水制备二甲醚

用浸渍法制备了负载型复合杂多酸催化剂H4SiW12O40-La2O3/γ-Al2O3,用于甲醇脱水制备二甲醚.用N2吸附、吡啶吸附红外光谱、NH3-TPD、XRD光谱等手段对催化剂进行了表征.考察了杂多酸负载量、浸渍时间、反应温度、质量空速等因素对催化活性的影响.实验结果表明：催化剂中H4SiW12O40负载量为10％～16％时催化剂的活性最好;在常压下反应温度为300℃,质量空速为1.0 h-1时,甲醇转化率达85％,二甲醚的选择性为99.9％;加压可提高催化剂的活性.     

甲醇缩合生成二甲醚的质谱和量子化学研究

利用质谱分析结果结合量子化学abinitio方法,研究甲醇缩合脱水的反应过程.研究表明,在气相中,甲醇分子主要以二聚体和多聚体的形式存在,据此提出甲醇脱水反应的原始反应物是甲醇二聚体,而不是单个甲醇分子.研究了气相甲醇二聚体、过渡态的能量和结构、甲醇脱水生成二甲醚反应的可能反应途径和反应势垒,对甲醇缩合脱水生成二甲醚的反应性及其影响因素作了讨论.     

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.