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1.
采用水溶液离子交换法制备了高Li+交换度的4A、13X和LSX分子筛,并在25 ℃下测定了它们的静态吸附等温线和动态穿透曲线.研究发现,高Li+离子交换度的4A、13X和LSX分子筛都具有较大的氮吸附容量和较高的氮氩分离选择性,说明高Li+离子交换度的4A、13X和LSX分子筛是较好的氮氩分离吸附剂.从动态穿透曲线结果来看,所研究的三种分子筛都有一个最优的吸附分离压力,在本文研究的压力范围内,这个最优压力在0.6 MPa附近.对比高锂交换度的三种分子筛,以高锂交换度的LSX分子筛的氮氩吸附分离性能最好. 相似文献
2.
不同分子筛的氮氩分离性能 总被引:1,自引:0,他引:1
采用水溶液离子交换法制备了不同离子交换的13X和4A分子筛,并在25℃下测 定了它们的静态吸附等温线和动态穿透曲线。研究发现,Ca~(2+)离子和Li~+离子 交换的13X和4A分子筛对氮的吸附性能都明显优于其相应的钠型分子筛,而它们对 氩的吸附量变化不大,说明这两种离子交换的分子筛是较好的氮氩分离吸附剂。从 动态吸附的结果来看,所研究的各种分子筛都有一个最优的吸附分离压力,在本论 文研究的压力范围内,这个最优压力在0.6MPa附近。通过穿透曲线推算出的混合气 体吸附量和纯气体吸附量的对比可以得出,对于氮氩吸附选择性较高的分子筛,氮 的存在对氩的吸附量有较大的影响。 相似文献
3.
Ca2+交换的几种分子筛的氮氩分离性能 总被引:1,自引:0,他引:1
采用水溶液离子交换法制备了Ca2+交换的4A、13X和LSX分子筛,并在25 ℃下测定了它们的静态吸附等温线和动态穿透曲线.研究发现, Ca2+交换的4A、13X和LSX分子筛对氮的吸附性能都明显优于其相应的钠型分子筛,而它们对氩的吸附量变化不大,说明Ca2+交换的这三种分子筛是较好的氮氩分离吸附剂.从动态吸附的结果来看,所研究的各种分子筛都有一个最优的吸附分离压力,在本论文研究的压力范围内,这个最优压力在0.6 MPa附近.由穿透曲线可推算出混合气体的吸附量,通过氮和氩在混合气体中的吸附量和相应纯气体吸附量的对比可以得出,对于氮氩吸附选择性较高的分子筛,氮的存在对氩的吸附量有较大的影响. 相似文献
4.
采用水溶液离子交换法制备了Ca2+交换的4A,13X和LSX分子筛,并在25 ℃下测定了它们的静态吸附等温线和动态穿透曲线.研究发现, Ca2+交换的4A,13X和LSX分子筛对氮的吸附性能都明显优于其相应的钠型分子筛,而它们对氩的吸附量变化不大,说明Ca2+交换的这三种分子筛是较好的氮氩分离吸附剂.从动态吸附的结果来看,所研究的各种分子筛都有一个最优的吸附分离压力,在本论文研究的压力范围内,这个最优压力在0.6 MPa附近.由穿透曲线可推算出混合气体的吸附量,通过氮和氩在混合气体中的吸附量和相应纯气体吸附量的对比可以得出,对于氮氩吸附选择性较高的分子筛,氮的存在对氩的吸附量有较大的影响. 相似文献
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测定了不同温度下氮、氩在5分子筛上的吸附等温线,其中三参数的Langmuir-Freundlich方程和Toth方程在不同温度下都能获得较好的拟合结果;计算了不同温度下氮、氩在5分子筛上吸附的亨利常数,获得了氮、氩选择性和温度的关系。测定了125K温度下氮、氩混合气体在5分子筛吸附柱上的穿透曲线。结果表明:最先流出的5L气体中含有约70%的氩,通过收集5L气体即可实现混合气体中氩的初步分离。 相似文献
8.
测定了不同温度下氮、氩在5分子筛上的吸附等温线,其中三参数的Langmuir-Freundlich方程和Toth方程在不同温度下都能获得较好的拟合结果;计算了不同温度下氮、氩在5分子筛上吸附的亨利常数,获得了氮、氩选择性和温度的关系.测定了125K温度下氮、氩混合气体在5分子筛吸附柱上的穿透曲线.结果表明:最先流出的5L气体中含有约70%的氩,通过收集5L气体即可实现混合气体中氩的初步分离. 相似文献
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本研究采用液相离子交换法,用不同浓度的CuCl2对NH4Y分子筛进行离子交换制得系列CuNH4Y-x分子筛吸附剂,并通过固定床吸附穿透实验及一系列表征手段探究了Cu的价态和负载量对乙烯/乙烷吸附分离性能的影响。吸附穿透实验结果表明,Cu(Ⅰ)NH4Y0.10的乙烯吸附量明显高于Cu(Ⅱ)NH4Y0.10,且Cu(Ⅰ)NH4Y系列吸附剂的乙烯吸附量随着Cu负载量的增加呈现先增加后减小的趋势。H2-TPR和HRTEM表明,当Cu的负载量较低时,高度分散落位于Y分子筛超笼中的Cu(Ⅰ)物种是乙烯有效吸附位点。然而,当Cu的负载量较高时,部分Cu物种发生团聚,造成对乙烯吸附能力的减弱。DFT密度泛函理论计算表明相比于Cu(Ⅱ)NH4Y吸附剂,乙烯更容易吸附在Cu(Ⅰ)NH4Y吸附剂上。该研究结果可为乙烯分离用高效Cu离子改性分子筛吸附剂的开发提供重要理论依据与指导。 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
12.
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
13.
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
14.
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
15.
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
16.
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
17.
An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions. 相似文献
18.
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
19.
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
20.
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