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1.
Crystalline nanoporous materials serve numerous pivotal functions in industrial chemistry. They provide crucial features for in- dustrial applications, such as high surface area, uniform porosity, inter-connected pore/channel system, accessible pore volume, high adsorp- tion capacity, ion-exchange ability, enhanced catalytic activity, and shape/size selectivity. As a well-established family of nanoporous materi- als, zeolites are of vital importance for the chemical and petrochemical industries. An emerging class of porous materials called metal organic frameworks (MOFs) also offer promise in various applications. Both zeolites and MOFs can play significant roles in fields that are critical for the future of our industrialized society. In the quest for raw material change, zeolites serve as catalysts providing the required shape/size selectivity towards base chemicals. In global efforts to transition into other transportation fuels such as Hydrogen, MOFs serve as the energy storage media. In the fight against environmental pollution, zeolites not only take part in capture and abatement of harmful substances, but also offer environmentally benign alternatives for many industrial processes. In this review, an industrial perspective on the synthesis and utilization of zeolites and MOFs for current and future applications is presented.  相似文献   

2.
ZSM-5 zeolite with a hexagonal cubic morphology was synthesized by a hydrothermal method using Triton X-100, a nonionic surfactant. The samples prepared with and without the surfactant were characterized by X-ray diffraction(XRD), Fourier transform infrared spectroscopy, N2 adsorption, high resolution transmission electron microscopy(TEM), high resolution scanning electron mi-croscopy, energy dispersive X-ray analysis, and NH3 temperature-programmed desorption. The XRD patterns confirmed the formation of a pure ZSM-5 crystalline phase without secondary phases. TEM images revealed that the hexagonal cubes were made of peanut-shaped nanoparticles with voids.The catalytic activity of the zeolite samples was evaluated using the selective oxidation of benzyl alcohol with tertiary-butyl hydrogen peroxide as the oxidant at 90 °C. The surfactant-assisted prep-aration yielded a zeolite that gave a higher conversion than the one prepared in the absence of the surfactant. The catalyst was retrieved and reused four times without significant loss in activity and selectivity.  相似文献   

3.
ZSM-5 zeolite with a hexagonal cubic morphology was synthesized by a hydrothermal method using Triton X-100, a nonionic surfactant. The samples prepared with and without the surfactant were characterized by X-ray diffraction(XRD), Fourier transform infrared spectroscopy, N2 adsorption, high resolution transmission electron microscopy(TEM), high resolution scanning electron mi-croscopy, energy dispersive X-ray analysis, and NH3 temperature-programmed desorption. The XRD patterns confirmed the formation of a pure ZSM-5 crystalline phase without secondary phases. TEM images revealed that the hexagonal cubes were made of peanut-shaped nanoparticles with voids.The catalytic activity of the zeolite samples was evaluated using the selective oxidation of benzyl alcohol with tertiary-butyl hydrogen peroxide as the oxidant at 90 °C. The surfactant-assisted prep-aration yielded a zeolite that gave a higher conversion than the one prepared in the absence of the surfactant. The catalyst was retrieved and reused four times without significant loss in activity and selectivity.  相似文献   

4.
分子筛作为一类重要的无机多孔晶体材料,由于其规整的孔道结构以及优异的酸性质等特点,在催化剂、吸附剂和离子交换床等许多领域有着重要而广泛的应用.而现代分子筛制备方法的发展主要得益于有机结构导向剂(OSDA)在分子筛合成中的广泛使用.但是,大部分OSDA都具有剧毒、价格昂贵、制备方法繁琐等缺点,因而限制了其大规模应用.高硅Y型分子筛的合成研究也面临同样的问题.Y型分子筛具有十二元环孔口和三维孔道结构,是目前催化裂化催化剂中的主要活性组分.目前,通过常规合成方法无法获得硅铝比大于6.0的Y型分子筛,无法满足石油化工对其酸性的要求.目前工业上主要通过后处理法得到高硅Y沸石,但该方法繁杂的后处理过程、不均匀的化学分布、大量损失的结晶度以及严重的环境污染促使人们开发直接合成高硅Y型分子筛的新方法以替代后处理过程.此外,使用OSDA一步法合成的高硅铝比Y型分子筛具有优异的热和水热稳定性.因此,使用OSDA一步直接合成高硅Y型分子筛在材料合成和催化领域一直备受关注.然而,目前尚未见关于绿色OSDA用于高硅Y型分子筛合成的报道.本研究首次将氢氧化胆碱或氯化胆碱作为一种新型、绿色、廉价的OSDA引入到高硅Y分子筛的合成凝胶体系,成功合成了高结晶度且硅铝比大于6.0的高硅Y型分子筛.实验详细考察了合成条件对硅铝比的影响,并采用XRD, XRF, NMR,TG以及N2物理吸附等表征手段研究了合成样品的物理化学性质.表征结果证明,胆碱阳离子作为一个稳定的OSDA存在于分子筛的孔结构中,并且取代了部分Na~+以平衡分子筛骨架的负电荷,因此胆碱的使用可使样品的硅铝比提高并具有更加优异的热稳定性和水热稳定性.实验确定了Na~+和OSDA~+在高硅Y分子筛合成中的竞争关系.大量的实验证据表明, Na~+进料比例对FAU骨架硅铝比有决定性的影响.首次提出采用氢氧根离子型OSDA是一种直接有效提高骨架硅铝比的方法.  相似文献   

5.
硅铝分子筛SSZ-13和硅磷铝分子筛SAPO-34已广泛应用于已商业化的催化应用中,如甲醇制烯烃反应(MTO)和氨气选择性催化还原反应(NH3-SCR).目前,已有多种商业化的有机结构导向剂(OSDA)可用于制备SAPO-34,而用于合成SSZ-13的OSDA仍主要依赖经典的N,N,N-三甲基-1-金刚烷基氢氧化铵(TMAdaOH).因此,寻找具有较高性价比且可导向合成高硅铝比(SAR)SSZ-13的OSDAs具有重要意义.本文使用3种可制备SAPO-34的OSDAs[二异丙胺(DIPA)、二丙胺(DPA)、正丁胺(nBA)]替代部分TMAdaOH,发现即使不加入晶种也可合成出SSZ-13.采用粉末X射线衍射(PXRD)和固体核磁共振(ss-NMR)分析方法对制备的SSZ-13进行了系统研究.结果显示,所合成的具有可调变SARs的SSZ-13负载Cu之后,在NH3-SCR性能上与商业化催化剂相当.此外,通过研究DIPA和TMAdaOH合成SSZ-13的晶化机理发现, DIPA的加入可以加快结晶过程、提高产率并防止非晶相的形成.本文提出的观点可为寻找更高效和商业化的SSZ-13结构导向剂及合成具有特定性质的SSZ-13提供参考.  相似文献   

6.
SAPO-34分子筛由于其独特的拓扑结构和适宜的酸性,在以甲醇制烯烃(MTO)和氨气选择性催化还原NOx (NH3-SCR)为代表的系列催化反应中显示了优良的性能,因此吸引了研究者的广泛关注。但是,在合成过程中如何通过选择有机模板和控制硅含量来得到合适酸量的SAPO-34催化剂是极具挑战的。本文中,四个系列的SAPO-34分子筛,即分别由四乙基氢氧化铵(TEAOH)、二异丙胺(DIPA)、正丁胺(nBA)和吗啉(MOR)为有机模板剂合成不同硅含量的样品,通过热重量分析(TG),结构精修和固态核磁进行了研究。TG和结构精修结果显示在TEAOH和DIPA合成的SAPO-34分子筛cha (一种复合结构单元)笼子中只有一个结构导向剂而MOR和nBA合成的SAPO-34分子筛的cha笼中有两个。采用固态核磁氢谱(1H ss-NMR)探究碱性探针分子氘代乙腈(CD3CN)和分子筛骨架之间主客体的相互作用,并对其酸性(酸量和酸强度)进行了系统的研究。例如,TEAOH合成的SAPO-34分子筛随着硅含量的增加酸强度增加而酸量却保持着不变。而DIPA合成的SAPO-34,与前者存在较大的差异,即随着硅含量的上升,酸量显著下降而酸强度只发生了微小的变化。该工作为SAPO-34分子筛催化剂酸性的定向调变提供了理论基础。  相似文献   

7.
硅铝分子筛SSZ-13和硅磷铝分子筛SAPO-34已广泛应用于已商业化的催化应用中, 如甲醇制烯烃反应(MTO)和氨气选择性催化还原反应(NH3-SCR). 目前, 已有多种商业化的有机结构导向剂(OSDA)可用于制备 SAPO-34, 而用于合成SSZ-13的OSDA仍主要依赖经典的N,N,N-三甲基-1-金刚烷基氢氧化铵(TMAdaOH). 因此, 寻找具有较高性价比且可导向合成高硅铝比(SAR)SSZ-13的OSDAs具有重要意义. 本文使用3种可制备SAPO-34的OSDAs[二异丙胺(DIPA)、 二丙胺(DPA)、 正丁胺(nBA)]替代部分TMAdaOH, 发现即使不加入晶种也可合成出SSZ-13. 采用粉末X射线衍射(PXRD)和固体核磁共振(ss-NMR)分析方法对制备的SSZ-13进行了系统研究. 结果显示, 所合成的具有可调变SARs的SSZ-13负载Cu之后, 在NH3-SCR性能上与商业化催化剂相当. 此外, 通过研究DIPA和TMAdaOH合成SSZ-13的晶化机理发现, DIPA的加入可以加快结晶过程、 提高产率并防止非晶相的形成. 本文提出的观点可为寻找更高效和商业化的SSZ-13结构导向剂及合成具有特定性质的SSZ-13提供参考.  相似文献   

8.
Effect of promoters such as Barium and Lanthanum has been investigated on the conventional nanostructured iron catalyst in Fischer-Tropsch synthesis (FTS). The nanosized iron-based catalysts were prepared by a microemulsion method with the general formulation of 100Fe/4Cu, 100Fe/4Cu/2La, 100Fe/4Cu/ 1La/1Ba, and 100Fe/4Cu/2Ba. The phase, structure, and morphology of the catalysts were characterized by X-ray diffraction, N2 adsorption, transmission electron microscopy, temperature-programmed desorption of CO2, and temperature- programmed reduction. The results indicated that the addition of promoters could improve the activity of Fe catalysts for FTS and WGS (water-gas shift reaction) and lower the gas fraction at the outlet. In addition, both Ba- and La-promoted Fe catalysts exhibit the highest activity due to the synergetic effect.  相似文献   

9.
1-苄基咪唑(L)与对苯二甲酸和Zn(NO_3)_2·6H_2O反应生成一维聚合链[ZnL_2(TP)]_n(1),在这个配合物中通过链间的C-H…π相互作用形成了二维超分子层。1-苄基咪唑(L)和CuCl_2·2H_2O反应生成四核配合物[Cu_4(μ_4-O)Cl_6L_4](2),在这个配合物中通过C-H…Cl氢键形成了一维超分子链。测定了L,1和2的荧光发射光谱。  相似文献   

10.
张优  赵灿  温一航 《无机化学学报》2014,30(11):2645-2652
采用3,5-二(4-吡啶)1,2,4-三唑(Hbpt)为配体与钴盐反应,在水热法条件下成功合成了3个配合物,分别是:[Co(Hbpt)2(HCOO)2(H2O)2]n·4nH2O(1),[Co(Hbpt)2(HCOO)2(H2O)2]n(2)和[Co(bpt)2(H2O)4]n·2nH2O(3),并通过X-射线单晶衍射和红外对它们进行了表征。配合物1和2均为三斜晶系,P1空间群,配合物3为单斜晶系,P21/c空间群。中心金属Co(Ⅱ)都是六配位,每个Co(Ⅱ)分别与2个Hbpt配体桥联而形成零维的结构单元,这些结构单元通过氢键和π-π堆积弱作用进一步连接而形成三维超分子网络结构。此外,还对配合物1和3的热稳定性做了分析。  相似文献   

11.
(1S,2S)-N-methyl-pseudoephedrine (MPS) was used as organic structure-directing agent (OSDA) for the synthesis of Mg-doped nanoporous aluminophosphates. This molecule displays a particular conformational behavior, where the presence of H-bond donor and acceptor groups provide a rigid conformational space with one asymmetric conformation preferentially occurring. MPS drives the crystallization of Mg-containing AFI materials. Characterization of these materials shows that the OSDA incorporate as protonated species, arranged as head-to-tail monomers. Combination of three-dimensional electron diffraction with high-resolution synchrotron powder X-ray diffraction allowed to locate both the Mg and the organic species. Interestingly, results showed that the spatial incorporation of Mg is driven by the hydroxyl groups of the organic cation through the development of H-bonds with negatively-charged MgO4 tetrahedra. This work demonstrates that H-bond forming groups can be used to drive the spatial incorporation of low-valent dopants within zeolitic frameworks, a highly desired aim in order to control their catalytic activity and selectivity.  相似文献   

12.
Two complexes CuLCl(H2O) 1 and Ni(L)2 2 (HL = 2-carboxy-1,10-phenanthroline) have been synthesized and characterized by single-crystal X-ray crystallography. The structure of 1 has a monoclinic space group P21/n with a = 7.985(2), b = 16.067(3), c = 9.694(2) A, β = 98.189(30)°, V= 1231.0(4) A^3, Z = 4, Dc = 1.836 g/cm^3,μ =1.998 mm^-1, F(000) = 684, the final R = 0.0301 and wR = 0.0810. The structure of 2 (C26H14N4NiO10) adopts an orthorhombic system, space group Pbea with a = 9.410(2), b = 23.2410(5), c = 23.8680(5) A, V = 5219.9(18) A^3, Z = 8, Mr = 601.12, Dc = 1,530 g/cm^3,μ = 0.809 mm^-1, F(000) = 2448, the final R = 0.0448 and wR = 0.1427. The Cu center of complex 1 exhibits a square pyramidal coordination environment with one oxygen and two nitrogen atoms from deprotonated 2-carboxy-1,10-phenanthroline, one oxygen atom from water and one chloride ion. The Ni center of complex 2 assumes a distorted octahedral coordination geometry consisting of two oxygen atoms and four nitrogen atoms of two deprotonated 2-carboxy-1,10-phenanthroline molecules. Supramolecular assembly has been found via noncovalent bonds, such as hydrogen bonds and π-π stacking interactions.  相似文献   

13.
One common strategy in the search for new zeolites is the use of organic structure-directing agents (OSDA). Typically, one seeks to achieve a high specificity in the structure-directing effect of the OSDA. This study shows, however, that an OSDA lacking strong specificity towards any particular zeolite may provide opportunities for discovery when other synthesis parameters are systematically screened. Thus, 1-methyl-2-ethyl-3-n-propylimidazolium has allowed to crystallize the new large/medium pore zeolite HPM-16 as well as the recently reported extra-large pore -SYT and the medium/small pore and chiral STW . The sophisticated OSDA originally affording -SYT and the new simple OSDA have very little in common, both in terms of size, shape and flexibility, while both may still direct the synthesis of the same zeolite. In fact, molecular simulations show that the new OSDA is located in three different positions of the -SYT structure, including the discrete 8MR where the original organic could not fit.  相似文献   

14.
A novel two-dimensional zinc phosphate Zn4P3O11(OH)·3CN2H4 in which the structure-directing organic amine acts as a ligand has been synthesized hydrothermally. The structure was solved by single-crystal X-ray diffraction analysis. Crystal data: triclinic, space group P1? (No. 2) with lattice parameters a=9.5663(15) Å, b=9.8530(16) Å, c=12.3658(19) Å, α= 77.495(4)°, β=77.893(4)°, γ=68.175(3)°, V=1045.6(3) Å3, Z=2, R1[I>2σ(I)]=0.0309, and wR2[I>2σ(I)]=0.0809. Interestingly the structure involves a network of ZnO4, PO4, PO3(OH), and the unusual ZnO3N and ZnO2N2 tetrahedra with shared vertices. There are 10-membered rings in the layers, in which the structure-directing imidazole molecules reside. The other amine molecules protrude from the Zn centers and occupy spaces between the layers.  相似文献   

15.

A new complex of lanthanum picrate with N,N'-diethyl-N,N'-diphennyl-3-oxapentanediamide (L) was synthesized and its structure determined by X-ray diffraction measurements. It crystallizes as the ten-coordinate complex La(pic)3L2 in the triclinic space group P1 with a = 12.140(2), b = 14.250(2), c = 20.333(2) Å, α = 101.400(10), β = 99.390(10), γ = 102.400(10)°, U = 3289.1(8) Å3, Z = 2, Dc = 1.519 g cm-3. The complex possesses a novel ladder-like 2-D supramolecular structure directed by π-π interactions.  相似文献   

16.
The reaction of 6,7-dicyanodipyridoquinoxaline (DICNQ) with AgNO3 in a 1:1 molar ratio by solution method gave a new complex [Ag(DICNQ)2]NO3 1. Single-crystal X-ray diffraction analysis reveals that the complex crystallizes in the space group Ibca of orthorhombic system with eight formula units in a cell. Crystal data for 1: a = 15.7055(17), b = 18.411(2), c = 20.680(2)A, V = 5979.7(11)A3, Z = 8, C32Hl2AgN13O3, Mr = 734.42, Dc = 1.632 g/cm3, μ= 0.734 mm-1, F(000) = 2928, S = 1.023 and T= 293(2) K. The final R = 0.0659 and wR = 0.1927 for 2118 observed reflections with I 〉 2σ(I), and R = 0.0801 and wR = 0.2196 for all data. The complex builds up a packing structure by π-π stacking interactions and shows a luminescent feature.  相似文献   

17.
在HMI体系中,采用水热动态晶化法,通过对Si/Al比,碱度,晶化温度,晶化 时间等反应条件进行调变,合成出纯相的MOR,ANA,MCM-56,MCM-49和MCM-22 等多种结构的沸石分子筛,发现反应物Si/Al比决定合成产物的物相,通过XRD, TG-DTA,SEM和TEM等方法研究了分子筛的物理化学性质并对HMI体系中合成的MOR 和ANA的晶体特征进行了表征分析。  相似文献   

18.
在微波辐射条件下合成了两种新的离子液体金属配合物[Ni(m-HNDA)2(H2O)4](1),[Zn(m-HNDA)2(H2O)4]·H2O(2),用元素分析、红外光谱、紫外光谱对它们进行了表征,通过X射线单晶衍射测定了它们的晶体结构.在晶体结构中,标题物通过基团间的嵌合作用,π-π相互作用和分子间氢键自组装成了三维网状的多孔结构.由氢键和π-π相互作用的强弱推测标题物的稳定性次序2>1,与实测热稳定性次序完全吻合;电化学性质表明,金属的配位改变了配体的循环伏安性质.另外,两种配合物可在水溶液中高选择性的识别氟离子.  相似文献   

19.
潘兆瑞 《无机化学学报》2011,27(10):2027-2032
由溶液法合成了2个稀土配合物{[Ln(Hmtyaa)3(H2O)2].H2O}n(Ln=Nd,1;Pr,2)(Hmtyaa=2-(5-甲基-1,3,4-噻二唑)-硫乙酸),用X-射线单晶衍射仪测定了配合物的单晶结构,并对其进行了元素分析、红外光谱、热重和粉末X-射线衍射等表征。晶体结构表明:配合物1和2结构相同,都属于三斜晶系,P1空间群。配合物中金属离子均采取九配位模式,金属离子被配体桥连形成一维双链结构,该一维双链被氢键和π-π作用连接成二维层状结构。  相似文献   

20.
利用溶液共混的方法将碳纳米管(CNT)及石墨烯(G)同时加入到热致液晶聚酯中制备纳米复合材料.通过透射电镜(TEM)研究纳米粒子的分散及形貌.采用荧光光谱及拉曼光谱研究碳纳米填料与热致液晶聚酯基体之间存在π-π相互作用.利用电子万能试验机(EUTM)研究了材料的拉伸性能,由于CNT与G与基材之间作用力强,且CNT与G间的协效作用能有效地实现应力转移,同时加入CNT及G有助于提升复合材料的拉伸强度.动态热机械分析(DMA)数据表明,同时添加CNT与G对于复合材料的固定率影响不大,但会降低回复率;同时复合材料的回复应力也得到显著的提升.  相似文献   

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