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1.
Ce掺杂对SnO2薄膜电学及气敏性能的影响 总被引:5,自引:1,他引:5
以无机盐SnCl2.2H2O(N4)3Ce(NO3)6为原料,无水乙醇为溶剂,采用溶胶-凝胶工艺制备了纯SnO2及SnO2:Ce薄膜。研究了SnO2:Ce薄膜的热分解晶化过程和Ce掺杂和SnO2薄膜的及气敏性能的影响,发现SnO2:Ce薄膜在常温下对H2S气体具有较妇的敢敏性能,对SnO2:Ce薄膜的结构进行了表征。 相似文献
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Ce2O—TiO2/SiO2的制备及除氟性能研究 总被引:5,自引:0,他引:5
以SiO2为基质,CeO2TiO2为包覆物质,采用溶胶凝胶法制备CeO2TiO2/SiO2表面复合物,并对所制复合物进行除氟测试。用扫描电镜(SEM)观察表面形貌,讨论实验环境、试剂用量等因素对CeO2TiO2/SiO2制备及除氟性能的影响,结果表明:nTi(OC4H9)4/nCeCl3·7H2O=1、nCH3COOH/nTi(OC4H9)4=45、nC3H8O3/nTi(O4H9)4=03、RH=95%,热处理温度110℃时,所制CeO2TiO2/SiO2对F-的吸附容量(q)为214mg/g,去除率(E)为856%。 相似文献
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水滑石焙烧产物Mg(Al)O为载体的Pt催化剂的正己烷临氢反应性能 总被引:1,自引:1,他引:1
制备了以水滑石焙烧产物-Mg-Al复合氧化物为载体的Pt催化剂,并考察了它在氢存在下的烃类转化反应性能,表明此类催化剂具有比一般的Pt/Al2O3更好的正己烷脱氢环化和异构化反应活性和选择性,更低的氢解反应活性。分别制备了以H2PtCl6、Pt(NH3)4(OH)2和Pt(NH3)4Cl2为浸渍剂的催化剂,其中以用Pt(NH3)4Cl2和Pt(NH3)4(OH)2制备的催化剂的脱氢环化反应和异构化 相似文献
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新型催化剂载体材料—镁铝复合氧化物的制备及其物理化学性质 总被引:39,自引:2,他引:39
以NaOH,Na2CO3混合或以NH4OH,(NH4)2CO3混合液为沉淀制备了Mg/Al=3-6.7的Mg-Al为滑石。将水滑石在500-600℃下焙烧制得了具有与Mgo相同的晶体结构的Mg(Al)L复合氧化物,它们的比表面积大于或接近γ-Al2O3,而且具有良好的热稳定性。 相似文献
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甲醇催化氧化重整反应制氢的研究 总被引:14,自引:1,他引:13
研究了Cu/Zn/Al系列催化剂催化甲醇氧化重整反应制氢,得到活性,选择性及稳定性较好的催化剂Cu60Zn30Al5Ce5;并且考察了Cu60Zn30Al5Ce5为催化剂时,该反应的工艺条件如温度,物料配比等,当压力为0.1MPa,温度为240℃,CH3OH:H2O=1:0.8,CH3OH:O2=4:1时,甲醇的转化率达97.75%,在此反应条件下,反应100h后,甲醇的转化率仍在96%以上。 相似文献
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采用等量浸渍法制备了Co/γAl2O3催化剂,考察了它们对乙烯选择还原NO的反应性能,用XRD和BET方法表征了催化剂.结果表明,在Co/γAl2O3中存在两种钴相,即Co3O4和CoAl2O4,前者是C2H4的完全氧化活性中心,后者是NO的选择性还原活性中心.随焙烧温度的提高,Co3O4向CoAl2O4相的转化是样品对C2H4完全氧化活性下降和对NO选择还原活性升高的主要原因.更高焙烧温度下,样品活性的下降与载体及CoAl2O4相的烧结有关. 相似文献
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标题化合物(Me_2SiSiMe_2)[η ̄5-(3-Me_3SiC_5H_3)Fe(CO)_2]_2/(μ-CO)_2(A)分子中的Fe-Fe键被钠汞齐还原断裂,生成相应的双铁负离子,分别与MeCOCl、PhCOCl、PhCH_2Cl、ClCH_2COOC_2H_5和Ph_3SnCl进行亲核取代反应,生成在铁原子上引入相应取代基的产物(Me_2SiSiMe_2)[η ̄5-(3-Me_3SiC_5H_3)Fe(CO)_2R]_2(R:MeCO(1),PhCO(2),PhCH_2(3),CH_2COOC_2H_5(4),Ph_3Sn(5),I(6))。A在氯仿中与碘反应,得到Fe-Fe断裂的双铁碘化物,但在苯中与过量碘反应,则得到Fe-I-Fe桥联的离子型化合物(Me_2SiSiMe_2)[η ̄5-(3-Me_3SiC_5H_3)Fe(CO)_2]_2I·I(7)。化合物6的晶体和分子结构经X射线衍射测定,6属单斜晶系,P21/c空间群,a=1.7217(4)nm,b=0.7753(2)nm,C=1.3629(7)nm,β=103.80(3)°,V=1.767(2)nm3,Z=4,Dc=1.6299·cm-1,最终偏差因子R=0.054。 相似文献
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用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%. 相似文献
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Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields. 相似文献
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Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction
Laurent Gavara Thomas Boisse Jean-Pierre Hénichart Adam Daïch Philippe Gautret 《Tetrahedron》2010,66(38):7544-5571
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments. 相似文献
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The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula. 相似文献
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Rebecca J. Burton Mandy L. CrowtherNeal J. Fazakerley Shaun M. FilleryBarry M. Hayter Jason G. KettleCaroline A. McMillan Paula PerkinsPeter Robins Peter M. SmithEmma J. Williams Gail L. Wrigley 《Tetrahedron letters》2013
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines. 相似文献
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KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields. 相似文献
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N. A. Nedolya 《Chemistry of Heterocyclic Compounds》2008,44(10):1165-1219
The review contains a concise historical account and information on the most significant researches undertaken by the staff
at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry
of Heterocyclic Compounds.
Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee.
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008. 相似文献
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A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL. 相似文献
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Regiospecific and direct imidation of the methyl C(sp3)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products. 相似文献
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A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions. 相似文献