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1.
激光促进磷酸盐表面甲烷直接氧化合成甲醇的研究   总被引:3,自引:0,他引:3  
以沉淀法合成了FePO4 、AlPO4 和Fe0 .5Al0 .5PO4 三种固体表面材料。采用XRD、IR和TPR方法对各材料进行了表征。以分子探针IR和TPD方法考察了甲烷在固体表面上的吸附性能。以固体表面键激发模式研究了激光促进甲烷直接氧化合成甲醇的表面反应规律。结果表明 ,FePO4 、AlPO4 和Fe0 .5Al0 .5PO4 均具有均一的晶态结构 ,其晶格氧的活泼性顺序为Fe0 .5Al0 .5PO4 >FePO4 >AlPO4 。在 1 0 0℃以上时 ,CH4 能够以分子态吸附于固体表面PO键上 ,各表面材料的吸附能力也遵循Fe0 .5Al0 .5PO4 >FePO4 >AlPO4 的规律。在 1 0 0~ 30 0℃范围内 ,采用 1 0 83cm- 1的激光激发固体表面PO键 ,CH4 直接氧化生成CH3OH的反应明显发生且CH3OH的选择性在 80 %以上。CH转化率的大小与固体表面材料晶格氧活泼性及其对CH4 的吸附能力有关。用 1 0 0 0cm- 1和 91 0cm- 1的激光激发PO键 ,不能有效促进化学反应的发生 ,揭示了激光光能的有效吸收和传递是LSSR过程能否实现的关键因素。  相似文献   

2.
甲烷部分氧化反应是目前催化研究领域的一个热点^[1,2],杂多酸以其确定的化学组成、特定的酸性和氧化性以及空间笼形结构而成为在分子水平上进行催化剂设计的良好选择^[3]。Kasztelan等^[4]曾利用SiO2负载的磷钨酸作为催化剂研究了CH4的氧化过程。激光促进表面反应(LSSR)技术已成为一种充满应用前景的光催化合成方法^[5,6]。本文以磷钼酸和CaF2负载磷钼酸为固体材料,TEA CO2激光器为光源,按固体表面键激发模式,考察了CH4部分氧化反应性能。  相似文献   

3.
CO2和CH3OH直接合成碳酸二甲酯用Cu-Ni/ZrO2-SiO2催化剂   总被引:26,自引:0,他引:26  
 采用表面反应改性法制备了ZrO2-SiO2(ZrSiO)表面复合物,用等体积浸渍法制备了ZrSiO担载的Cu-Ni双金属催化剂,并用IR,TPD,TPSR和微反技术考察了CO2和CH3OH在催化剂表面上的化学吸附及反应性能.实验结果表明:在Cu-Ni/ZrSiO催化剂上存在着Cu-Ni金属位M,Lewis酸位Zrn+和Lewis碱位Zr-O-三类活性中心;CO2在金属位和Lewis酸位的协同作用下可形成CO2卧式吸附态,此吸附态在142℃左右可解离成M-CO和Zr-O-;CH3OH在Lewis酸位和Lewis碱位的协同作用下可形成解离吸附态Zr-OCH3和Zr-OH;CO2和CH3OH在Cu-Ni/ZrSiO催化剂表面上的主要反应产物为碳酸二甲酯(选择性在85%以上),另有少量的CH2O,CO和H2O.  相似文献   

4.
 采用表面改性法制备了负载型Sn2(OMe)4/SiO2双核桥联配合物催化剂,用IR,TPD和微反技术对催化剂的表面结构、化学吸附性质和催化活性进行了研究.结果表明,双核桥联Sn2(OMe)4/SiO2配合物中存在Sn-O-Si双齿配位形式,甲氧基以桥基形式联结两个Sn4+离子;CO2在催化剂表面以桥式吸附态和甲氧碳酸酯基吸附态存在,而CH3OH只以分子吸附态存在.在反应温度413K,压力0.5MPa,反应空速1500h-1以及CH3OH与CO2的摩尔比为2~2.5的反应条件下,CO2和CH3OH在Sn2(OMe)4/SiO2催化剂上生成碳酸二甲酯的选择性达到近100%.根据实验结果,提出了CO2与CH3OH在Sn2(OMe)4/SiO2催化剂表面上的反应机理,反应物分子共吸附于催化剂表面同一活性位上及CO2的甲氧碳酸酯基吸附态的形成是反应顺利进行的关键因素.  相似文献   

5.
用溶胶—凝胶法合成了非晶态Fe0.5Al0.5PO4。用XRD和TPR表征了其结构和晶格氧的活性;用IR和TPD表征了CH4在其表面上的吸附行为;用LSSR方法考察了CH4直接氧化合成CH3OH的反应规律。结果表明,Fe0.5Al0.5PO4具有非晶态的结构,FePO4和AlPO4的微区被均匀地相互隔离,导致固体本身不具有长程有序性。非晶态的Fe0.5Al0.5PO4与晶态的Fe0.5Al0.5PO4相比,其晶格氧的活性大且活性氧的含量高。CH4以分子态吸附于固体表面P=O键上,非晶态Fe0.5Al0.5PO4表面上CH4的吸附强度和吸附量都较晶态Fe0.5Al0.5PO4上大。用1073 cm-1的激光激发固体表面P=O键,在100℃以上CH4的直接氧化反应顺利进行,CH3OH保持高选择性。在相同的反应条件下,非晶态Fe0.5Al0.5PO4能更有效地促进反应的进行,表明在激发相同表面化学键的情况下,固体表面材料的其它性质如粒度、比表面积和晶格氧的活性对反应也有一定程度的影响。  相似文献   

6.
制备了硫酸镍固体材料.采用红外光谱(IR)、程序升温脱附(TPD)和激光促进表面反应(LSSR)技术,研究了乙烯在NiSO4表面上的化学吸附态和激光促进C2H4表面反应性能.实验结果表明,C2H4以H原子与固体材料表面Lewis碱位(S=O键中的端氧)作用,形成分子吸附态.在常压和100 ℃条件下,用1079 cm-1激光激发吸附有C2H4分子中H的S=O键100次, C2H4转化率可达15%,生成丁二烯的选择性为100%.根据表征和反应结果,讨论了C2H4在NiSO4上的LSSR机理和影响LSSR性能的因素.  相似文献   

7.
陶跃武  钟顺和 《催化学报》2001,22(2):129-132
 用共沉淀法制备了Bi和Mo的复合氧化物固体材料.运用XRD,IR,TPD和激光促进表面反应(LSSR)技术研究了其晶体结构、表面构造、化学吸附特性和激光促进异丁烷选择氧化反应性能.结果表明:Bi-Mo-O复合氧化物含有α-Bi2Mo3O12和少量γ-Bi2MoO6晶相;其表面上存在着Lewis碱位(MoO和Mo—O—Bi键中的O)及Lewis酸位(Bi3+);异丁烷的两个甲基H分别吸附在两个相邻的Lewis碱位MoO上,形成双位分子吸附态;在常压和200℃条件下,用一定频率的激光激发MoO键1000次,异丁烷的转化率可达11.2%,其反应产物是异丁烯、甲基丙烯醛和甲基丙烯酸,其中甲基丙烯酸的选择性为90%.根据实验结果,探讨了激光促进异丁烷选择氧化为甲基丙烯酸的表面反应机理.  相似文献   

8.
利用红外光谱和激光表面反应技术,研究了丁醇在SiO_2、γ-Al_2O_3和Fe_2O_3表面上的激光表面反应机理。根据不同固体表面和不同激发模式只影响激光表面反应的能量利用率而反应产物分布类同的实验结果,确定了丁醇在固体表面上的吸附态及受激吸附态分子内键与键间的能量传递是决定反应产物选择性的主要因素。  相似文献   

9.
本文利用红外光谱、化学吸咐和激光表面反应技术,研究了丁烷在H-ZSM-5分子筛、SiO_2和γ-A1_2O_3表面上的激光表面反应规律;研究了不同激发模式、固体表面材料的红外特性及化学吸附能力、激光脉冲次数及脉冲间隔时间等因素对激光光能利用率的影响;证实了固体表面键激发模式的有效性,探讨了激光表面反应过程中能量吸收、积累、传递和损失的途径,提出了激光促进丁烷裂解的表面反应机理。  相似文献   

10.
桑丽霞  钟顺和 《化学通报》2002,65(12):805-810
概述了甲烷直接转化为甲醇的光化学和光促表面反应的研究,分析了不同反应体系、不同光源(可见光、紫外光和激光)及不同固体表面材料对甲烷转化率和甲醇选择性的影响,并讨论了“光-表面”对甲烷活化的协同作用。  相似文献   

11.
[8+12]-metallamacrocycle-based 3D frameworks {[Cu(4)(pbt)(2)(SO(4))(2)(DMF)(2)(CH(3)OH)]·7H(2)O·DMF}(n) (1) and [12]-macrocycle 3D {[Cu(2)(pbt)(SO(4))(DMSO)(CH(3)OH)(2)]·5H(2)O·CH(3)OH}(n) (2) have been obtained. Both complexes display antiferromagnetic couplings and high catalytic activity in the oxidative coupling reaction of 1-ethynylbenzene and oxazolidin-2-one.  相似文献   

12.
用沉淀法制备了Li3PO4、BiPO4和Li3PO4、BiPO4三种固体表面材料,并用XRD、IR、TPD和激光促进表面反应(LSSR)等技术研究了这些固体表面上甲醇氧化偶联生成乙二醇的反应规律。实验结果表明:甲醇在固体材料表面的P=9键上产生C-H端的分子态吸附,在表面的Lewis酸位(金属离子)上产生解离态吸附。Li3PO4和BiPO4的相互作用可促进甲醇在固体表面上的分子态吸附而抑制解离态吸  相似文献   

13.
Hydrothermal reactions of a vanadate source, an appropriate Cu(II) source, bisterpy and an organodiphosphonate, H2O3P(CH2)nPO3H2(n= 1-5), in the presence of HF, yielded a family of materials of the type oxyfluorovanadium/copper-bisterpy/organodiphosphonate. Under similar reaction conditions, variations in diphosphonate tether length n provided the one-dimensional [{Cu2(bisterpy)}V2F2O2{HO3PCH2PO3}{O3PCH2PO3}](1) and [{Cu2(bisterpy)}V2F4O4{HO3P(CH2)2PO3H}](3), the two-dimensional [{Cu2(bisterpy)}V2F2O2(H2O)2{HO3P(CH2)2PO3}2] x 2H2O (2 x 2H2O), [{Cu2(bisterpy)(H2O2}V2F2O2{O3P(CH2)3PO3}{HO3P(CH2)3PO3H}(4) and [{Cu2(bisterpy)}V4F4O4(OH)(H2O){HO3P(CH2)5PO3}{O3P(CH2)5PO3}] x H2O (9 x H2O) and the three-dimensional [{Cu2(bisterpy)}3V8F6O17{HO3P(CH2)3PO3}4]0.8H2O (5 x 0.8H2O), [{Cu2(bisterpy)}V4F2O6{O3P(CH2)4PO3}2](8) and [{Cu2(bisterpy)(H2O)}2V8F4O8(OH)4{HO3P(CH2)5PO3H}2{O3P(CH2)5PO)}3] x 4.8H2O (10 x 4.8H2O). In addition, two members of the oxovanadium/Cu2(bisterpy)/organodiphosphonate family [{Cu2(bisterpy)}V2O4{HO3P(CH2)3PO3}2](6) and [{Cu2(bisterpy)}3V4O8(OH)2{O3P(CH2)3PO3}2{HO3P(CH2)3PO3}2] x 5H2O (7 x 5H2O) cocrystallized from the reaction mixture which provided 5. The overall architectures reveal embedded substructures based on V/P/O(F) clusters, chains, networks, and frameworks. In contrast to the oxovanadium/Cu2(bisterpy)/ organodiphosphonate family, several of the materials of this study also exhibit the direct condensation of vanadium polyhedra to produce binuclear and/or tetranuclear building units.  相似文献   

14.
The hydrothermal reaction of CuSO(4).5H2O, Na2MoO(4).2H2O and 2,2'-bipyridine with the bridging diphosphonate ligand H2O3P(CH2)4PO3H2 yields the one-dimensional chain [(Cu(bpy)2)(Cu(bpy)(H2O)2)(Mo5O15)(O3P(CH2)4PO3)].H2O; the introduction of a second bridging component in the reaction of Cu(MeCO2)2.H2O, MoO3, H2O3PCH2CH2PO3H2 and tetra(2-pyridyl)pyrazine yields the network solid [(Cu2(tpypyz)(H2O)2)(Mo5O15)(O3PCH2CH2PO3)].5.5H2O.  相似文献   

15.
A novel, three-dimensional copper diphosphonate Cu4(CH3C(OH)(PO3)2)2(C4H4N2)(H2O)4 (1) incorporating an organic pyrazine ligand has been hydrothermally synthesized, which exhibits antiferromagnetic ordering below 4.2 K and metamagnetic behavior.  相似文献   

16.
The hydrothermal reaction of phosphonoacetic acid (H2PO3CH2C(O)OH, PAA) with UO3 and Cu(C2H3O2)2 .H2O results in the formation of the crystalline heterobimetallic uranium(VI)/copper(II) phosphonates UO2Cu(PO3CH2CO2)(OH)(H2O)2 ( UCuPAA-1), (UO2) 2Cu(PO3CH2CO2)2(H2O)3 (UCuPAA-2), and [H3O][(UO2) 2Cu2(PO3CH2CO2)3(H2O)2 ( UCuPAA-3). The addition of sodium hydroxide to the aforementioned reactions results in the formation of Na[UO2(PO3CH2CO2)].2H2O (NaUPAA-1). These compounds display 1D (UCuPAA-1), 2D (UCuPAA-2, NaUPAA-1), and 3D (UCuPAA-3) architectures wherein the phosphonate portion of the ligand primarily coordinates the uranium(VI) centers; whereas the carboxylate moiety preferentially, but not exclusively, binds to the copper(II) ions. Fluorescence measurements on all four compounds demonstrate that the presence of copper(II) mostly quenches the emission from the uranyl moieties.  相似文献   

17.
Synthetic mineral libethenite Cu(2)PO(4)OH was prepared by the hydrothermal method, and its structure at 200 K was refined by single-crystal X-ray diffraction. The structure of Cu(2)PO(4)OH is built up from Cu2(2)O(6)(OH)2 dimers of edge-sharing Cu2O(4)(OH) trigonal bipyramids and [Cu1(2)O(6)(OH)(2)] proportional chains of edge-sharing Cu1O(4)(OH)(2) octahedra. Magnetic properties of Cu(2)PO(4)OH were investigated by magnetic susceptibility, magnetization, and specific heat measurements. Cu(2)PO(4)OH is a spin-gap system with a spin gap of about 139 K. It was shown by spin dimer analysis that, to a first approximation, the magnetic structure of Cu(2)PO(4)OH is described by an isolated square-spin cluster model defined by the Cu1-O-Cu2 superexchange J with Cu1...Cu2 = 3.429 A. The fitting analysis of the magnetic susceptibility data with a square-spin cluster model results in J/k(B) = 138 K. Specific heat data show that Cu(2)PO(4)OH does not undergo a long-range magnetic ordering down to 1.8 K. We also report vibrational properties studied with Raman spectroscopy and the thermal stability of Cu(2)PO(4)OH.  相似文献   

18.
A sterically hindered aryl phosphonic acid ArP(O)(OH)2 (2) (Ar = 2,4,6-isopropylphenyl) was synthesized and structurally characterized. ArP(O)(OH)2 forms an interesting hydrogen-bonded corrugated sheet-type supramolecular structure in the solid-state. A three-component reaction involving ArP(O)(OH)2, 3,5-dimethylpyrazole(DMPZH), and Cu(CH3COO)2.H2O produces the tetranuclear Cu(II) compound [Cu4(mu3-OH)2{ArPO2(OH)}2(CH3CO2)2(DMPZH)4][CH3COO]2.CH2Cl2 (3). A similar three-component reaction involving ArP(O)(OH)2, 3,5-dimethylpyrazole, and Zn(CH3COO)2.2H2O yields the tetranuclear Zn(II) compound [Zn4{ArPO3}2{ArPO2(OH)}2{DMPZH}4(DMPZ)2].5MeOH (4). While 3 has been found to have an asymmetric cage structure where two dinuclear copper cores are bridged by bidentate [ArPO2(OH)]- ligands, 4 possesses an open-book tricyclic structure composed of three fused metallophosphonate rings. Magnetic studies on 3 revealed antiferromagnetic behavior.  相似文献   

19.
Hydrothermal reactions of Na3VO4, an appropriate Cu(II) source, bisterpy and an organodiphosphonate, H2O3P(CH2)nPO3H2 (n = 1-6) yielded a family of materials of the type [Cu2(bisterpy)]4+/VxOy(n-)/[O3P(CH2)nPO3]4-. This family of bimetallic oxides is characterized by an unusual structural diversity. The oxides [[Cu2(bisterpy)]V2O4[O3PCH2PO3H]2] (1), [[Cu2(bisterpy)(H2O)]VO2[O3P(CH2)3PO3][HO3P(CH2)3PO3H2]] (4) and [[Cu2(bisterpy)]V2O4[O3P(CH2)6PO3H]2].2H2O (7.2H2O) are one-dimensional, while [[Cu2(bisterpy)(H2O)2]V2O4[O3P(CH2)2PO3][HO3P(CH2)2PO3H]2] (2), [[Cu2(bisterpy)]V4O8[O3P(CH23PO3]2].4H2O (3.4H2O) and [[Cu2(bisterpy)]V2O4(OH)2[O3P(CH2)4PO3]].4H2O (5.4H2O) are two-dimensional. The V(IV) oxide [[Cu2(bisterpy)]V4O4[O3P(CH2)5PO3H]4].7.3H2O (6.7.3H2O) provides a relatively unusual example of a three-dimensional bimetallic oxide phosphonate. The structures reveal a variety of V/P/O substructures as building blocks.  相似文献   

20.
The copper(II) complexes [Cu(4)(1,3-tpbd)(2)(H(2)O)(4)(NO(3))(4)](n)(NO(3))(4n)·13nH(2)O (1), [Cu(4)(1,3-tpbd)(2)(AsO(4))(ClO(4))(3)(H(2)O)](ClO(4))(2)·2H(2)O·0.5CH(3)OH (2), [Cu(4)(1,3-tpbd)(2)(PO(4))(ClO(4))(3)(H(2)O)](ClO(4))(2)·2H(2)O·0.5CH(3)OH (3), [Cu(2)(1,3-tpbd){(PhO)(2)PO(2)}(2)](2)(ClO(4))(4) (4), and [Cu(2)(1,3-tpbd){(PhO)PO(3)}(2)(H(2)O)(0.69)(CH(3)CN)(0.31)](2)(BPh(4))(4)·Et(2)O·CH(3)CN (5) [1,3-tpbd = N,N,N',N'-tetrakis(2-pyridylmethyl)-1,3-benzenediamine, BPh(4)(-) = tetraphenylborate] were prepared and structurally characterized. Analyses of the magnetic data of 2, 3, 4, and [Cu(2)(2,6-tpcd)(H(2)O)Cl](ClO(4))(2) (6) [2,6-tpcd = 2,6-bis[bis(2-pyridylmethyl)amino]-p-cresolate] show the occurrence of weak antiferromagnetic interactions between the copper(II) ions, the bis-terdentate 1,3-tpbd/2,6-tpcd, μ(4)-XO(4) (X = As and P) μ(1,2)-OPO and μ-O(phenolate) appearing as poor mediators of exchange interactions in this series of compounds. Simple orbital symmetry considerations based on the structural knowledge account for the small magnitude of the magnetic couplings found in these copper(II) compounds.  相似文献   

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