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以Sm(NO3)3.6H2O和Ce(NO3)3.6H2O为原料,用共沉淀-喷雾干燥法制备了Sm2O3掺杂CeO2(SDC)粉体。通过沉降实验、TG-DSC、XRD、BET、SEM和粒度分布对前驱体的分散性、稳定性及制得的SDC粉体性能进行表征,研究了洗涤方法、分散剂对前驱体及SDC粉体的影响。结果表明:无机陶瓷膜洗涤后前驱体分散性好,经500℃以上温度焙烧后的粉体为立方萤石型结构。加入分散剂后前驱体的分散性明显提高,制得的SDC粉体比表面积显著增加,最终获得了晶粒平均粒径为12.51 nm、团聚态颗粒为球形的SDC纳米粉体。 相似文献
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沉淀温度对CuO/ZnO/Al2O3催化剂前驱体物相及催化水煤气变换反应活性的影响 总被引:4,自引:0,他引:4
用X射线衍射、差热热重测定、程序升温还原、N2吸附、N2O滴定和常压微反活性评价技术考察了沉淀温度对CuO/ZnO/Al2O3系催化剂及其前驱体的物相和催化水煤气变换反应活性的影响. 结果表明,在沉淀温度为60~90 ℃时,催化剂前驱体中主要存在Cu2CO3(OH)2,(Cu,Zn)2CO3(OH)2和(Cu,Zn)6Al2(OH)16CO3·4H2O三种物相. 焙烧后的催化剂样品中形成了较多的CuO-ZnO固溶体,沉淀温度升高有利于CuO-ZnO固溶体的形成及催化剂活性的提高. 水煤气变换反应是一个非结构敏感型反应. 相似文献
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在水中由Na2 WO4 ·2H2 O ,Na2 MoO4 ·2H2 O和KH2 PO4 ·2H2 O反应生成具有半Dawson结构的钨钼混配杂多阴离子Na9PW6Mo3O34 ·1 0H2 O。以阴离子和过渡金属硝酸盐为原料在水溶液中合成了一系列过渡金属二取代的具有Keggin结构的杂多酸四丁基铵盐 [TBA]4 Hn[PW7Mo3M2 O38(H2 O) 2 ]·C3H6O(n =1 ,M =Fe3+;n =3,M =Mn2 +,Co2 +,Ni2 +,Cu2 +) ,用元素分析和波谱进行了表征。 相似文献
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L 苏糖酸作为金属离子的载体,可使金属离子易于与氨基酸或蛋白质结合而被动物吸收和利用[1-3],钒在1971年被确定为生物体必需的微量元素[4],具有多种生理作用和药理活性,与糖尿病的关系十分密切。近年来国内外用于抗糖尿病生物学研究的钒化合物绝大多数为简单的盐类化合物,脂溶性小,难以吸收,同时对胃肠道刺激性大[5]。本文以L 苏糖酸钙与草酸氧钒(VOC2O4)反应后的溶液加无水乙醇制得[VO(C4H6O5)]2·3H2O,并进行等离子发射光谱(ICP)、元素分析、IR光谱、TG DTG表征。1 实验部分1.1 试剂与仪器L 抗坏血酸(Vc),H2C2O4·2H2O… 相似文献
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室温或近室温固相反应要求绿色化、清洁化[1,2]。我们以KMnO4和MnCl2·4H2O为原料,用室温固相氧化还原反应制备氧化锰粉体时,得到了一种对H2O2分解具有较高催化活性的纳米KMn8O16粉体,用XRD、SEM、IR等技术对其进行了表征,发现研磨时间对粉体性能有显著影响。1 实验部分1 1 粉体的制备按摩尔比(2∶3)准确称取一定量的分析纯KMnO4和MnCl2·4H2O,分别置于玛瑙研钵中充分研细,再混合研磨,固相反应立即发生,体系颜色逐渐加深,并有刺激性气体产生,充分研磨后70℃恒温12h,固相产物依次经水洗至中性、醇洗、抽滤,真空干燥得黑色粉… 相似文献
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氨基酸与金属微量元素形成的配合物广泛存在于动植物体中并参与许多生命过程。我们在前文[1 ,2 ] 基础上制备了Na2 [Zn(Cys) 2 ]·5H2 O ,通在2 98 2K用具有恒定温度环境的反应热量计[3] 测定了反应物和生成物在4mol·L- 1 HCl溶液中的溶解焓,过热化学循环计算出配合物的标准生成焓△fH m(Na[Zn(Cys) 2 ]·5H2 O ,s) =- 2 82 8 32 3kJ·mol 1 。1 实验部分1 .1 试剂与仪器L 半胱氨酸(L cys)为生化试剂,纯度>99 0 % ,ZnSO4·7H2 O、C2 H5OH、Na2 SO4、NaOH为分析纯试剂,实验用水均为二次蒸馏水。UV 2 5 0型紫外可见光谱仪(… 相似文献
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纳米氧化铁制备中的团聚问题 总被引:3,自引:0,他引:3
纳米材料是近年来的研究热点。通常的纳米Fe2O3粒子制备过程中处理温度高,粒子易团聚,难于分离[1~4]。本文用溶胶 凝胶 相转移法制得粒径为20-50nm的Fe2O3,胶溶过程控制pH在2左右,煅烧温度降至420℃,用无水氯化钙、无水硫酸钠两级脱水干燥,减小了团聚,使其更具实用性。1 实验取23 8gFeCl3·6H2O溶于500ml蒸馏水,取200ml此三氯化铁溶液,搅拌下逐滴加入10ml氨水与40ml蒸馏水的混合液中直至其显弱碱性。将沉淀过滤,洗涤,在滤液中加硝酸银溶液至无白色沉淀。胶溶剂为0 7~1 5mol/LFeCl3溶液,用量40ml,胶溶温度70℃左右,pH值控制在2… 相似文献
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Uroš Grošelj Mojca Žorž Amalija Golobič Branko Stanovnik Jurij Svete 《Tetrahedron》2013,69(52):11092-11108
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. 相似文献
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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. 相似文献
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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%). 相似文献
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Shashikant U. Dighe Surya K. Samanta Shivalinga Kolle Sanjay Batra 《Tetrahedron》2017,73(17):2455-2467
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. 相似文献
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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. 相似文献
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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. 相似文献
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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. 相似文献
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Jona Mirnik Eva Pušavec Kirar Sebastijan Ričko Uroš Grošelj Amalija Golobič Franc Požgan Bogdan Štefane Jurij Svete 《Tetrahedron》2017,73(24):3329-3337
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 CuI 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). 相似文献
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George E. Magoulas Thomas Garnelis Constantinos M. Athanassopoulos Dionissios Papaioannou George Mattheolabakis Konstantinos Avgoustakis Dimitra Hadjipavlou-Litina 《Tetrahedron》2012,68(35):7041-7049
(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. 相似文献