Facile Surface Engineering of NiCo_(2)O_(4) to Boost Propane Oxidation Activity

Spinel oxide(NiCo_(2)O_(4))has demonstrated great potential to replace noble metal catalysts for the oxidation reaction of air pollutants.To further boost the oxidation ability of such catalysts,in this study,a facile surface-engineering strategy wherein NiCo_(2)O_(4) was treated with different alkali solvents was developed.The obtained catalyst(NiCo_(2)O_(4)-OH)showed a higher surface alkalinity and more surface defects compared to the pristine spinel oxide,including enhanced structural distortion as well as promoted oxygen vacancies.The propane oxidation ability of NiCo_(2)O_(4)-OH was greatly enhanced,with a propane conversion rate that was approximately 6.4 times higher than that of pristine NiCo_(2)O_(4) at a reaction temperature 193℃.This work sets a valuable paradigm for the surface modulation of spinel oxide via alkali treatment to ensure a high-performance oxidation catalyst.

有机-无机杂化材料[Ag(bpp)]_2(tdc)·8H_2O的合成,结构和光学性能(bpp=1,3-bis(4-pyridyl)propane,tdc=thiophene-2,5-dicarboxylate)(英文)

在室温下,AgNO3、1,3-二(4-吡啶基)丙烷和2,5-噻吩二甲酸在丙酮水溶液中反应,经数周后得到完整无色晶体[Ag(bpp)]2(tdc)·8H2O。该晶体由荷正电的类似正弦曲线形状的配位聚合物链,[Ag(bpp)]∞,和有机负离子tdc2-构成,其间分布着起重要作用的结晶水分子。相邻的阳离子链通过静电作用与tdc2-阴离子堆积构成晶体的三维骨架,结晶水分子分布其间并形成氢键,对晶体堆积起定位作用。[Ag(bpp)]2(tdc)·8H2O的晶体学数据:单斜晶系,空间群C2/c,a=3.5447nm,b=0.92003nm,c=2.4119nm,β=106.56°,V=7.546nm3和Z=8;残差因子R1=0.0463,wR2=0.1142。UV/Vis/NIR漫反射光谱法测定表明其具有很强的选择性光吸收特性。

PtSnNa/SUZ-4:An efficient catalyst for propane dehydrogenation

The structure and catalytic properties of PtSn catalysts supported on SUZ-4 and ZSM-5 zeolite have been studied by using various experimental techniques including XRD,nitrogen adsorption,NH3-TPD,TG,H2-TPR and TPO techniques combined with propane dehydrogenation tests.It has been shown that SUZ-4-supported PtSnNa（PtSnNa/SUZ-4） was determined to be a better catalyst for propane dehydrogenation than conventional catalysts supported on ZSM-5,owing to its higher catalytic activity and stability.Dibenzothiophene poisoning experiments were performed to investigate the detailed structures of the two supported catalysts.The characterization of the two catalysts indicates that the distribution of Pt on the porous support affects the activity.In contrast to ZSM-5-supported catalysts,Pt particles on the PtSnNa/SUZ-4 are primarily dispersed over the external surface and are not as readily deactivated by carbon deposition.This is because that the strong acid sites of the SUZ-4 zeolite evidently prevented the impregnation of the Pt precursor H_2PtCl_6 into the zeolite.In contrast,the weak acid sites of the ZSM-5 zeolite led to more of the precursor entering the zeolite tunnels,followed by transformation to highly dispersed Pt clusters during calcination.In the case of the PtSnNa/ZSM-5,the interactions between Sn oxides and the support were lessened,owing to the weaker acidity of the ZSM-5 zeolite.The dispersed Sn oxides were therefore easier to reduce to the metallic state,thus decreasing the catalytic activity for hydrocarbon dehydrogenation.

Synthesis,Crystal Structure and Characterization of a New Coordination Polymer from the Self-assembly of CoCl_2 Salt and Flexible Ligand 1,3-Bis(4-pyridyl)propane

A new 1D coordination polymer [Co（bpp）3Cl2（H2O）2]n 1 （bpp = 1,3-bis（4-pyridyl）-propane） was synthesized and characterized by elemental analysis,IR spectrum and single-crystal X-ray diffraction. The crystal belongs to the orthorhombic system,space group Ibca with a = 16.569（9）,b = 17.240（10）,c = 27.087（16） ,V = 7738（8） 3,Z = 8,Dc = 1.306 g/cm3,Mr = 760.65,λ（MoKa） = 0.71073 ,μ = 0.623 mm1,F（000） = 3192,the final R = 0.0678 and wR = 0.2011. The Co（II） atom is coordinated in a slightly distorted octahedral CoN4Cl2 geometry by two Cl atoms in the axial positions,four N atoms from the two bridging bpp ligands and two pendant bpp ligands. The CoN4Cl2 octahedra are connected by the bridging bpp ligands to form a 1D neutral coordination polymer chain. The chains are linked by face-to-face π-π interactions between adjacent pendant bpp ligands to give rise to a 3D supramolecular architecture. The photoluminescent investigation indicates that the emission of 1 is attributed to ligand-centered emission. The variable-temperature magnetic susceptibility measurement shows weak antiferromagnetic behavior in the coπmplex.

Synthesis of a new ordered mesoporous NiMoO_4 complex oxide and its efficient catalytic performance for oxidative dehydrogenation of propane

Highly ordered mesoporous NiMoO4 material was successfully synthesized using mesoporous silica KIT-6 as hard template via vacuum nanocasting method. The structure was characterized by means of XRD, TEM, N2 adsorption-desorption, Raman and FT-IR. The mesoporous NiMoO4 with the coexistence of a-NiMoO4 and fl-NiMoO4 showed well-ordered mesoporous structure, a bimodal pore size distribution and crystalline framework. The catalytic performance of NiMoOa was investigated for oxidative dehydrogenation of propane. It is demonstrated that the mesoporous NiMoO4 catalyst with more surface active oxygen species showed better catalytic performance in oxidative dehydrogena- tion of propane in comparison with bulk NiMoO4.

Insight into catalytic properties of Co3O4-CeO2 binary oxides for propane total oxidation

A series of Co3O4-CeO2 binary oxides with various Co/(Ce+Co)molar ratios were synthesized using a citric acid method,and their catalytic properties toward the total oxidation of propane were examined.The activities of the catalysts decrease in the order CoCeOx-70>CoCeOx-90>Co3O4>CoCeOx-50>CoCeOx-20>CeO2.CoCeOx-70(Co/(Ce+Co)=70% molar ratio)exhibits the highest catalytic activity toward the total oxidation of propane,of which the T90 is 310℃(GHSV=120000 mL h^-1 g^-1],which is 25℃ lower than that of pure Co3 O4.The enhancement of the catalytic performance of CoCeOx-70 is attributed to the strong interaction between CeO2 and Co3O4,the improvement of the low-temperature reducibility,and the increase in the number of active oxygen species.In-situ DRIFTS and reaction kinetics measurement reveal that Ce addition does not change the reaction mechanism,but promotes the adsorption and activation of propane on the catalyst surface.The addition of water vapor and CO2 in reactant gas has a negative effect on the propane conversion,and the catalyst is more sensitive to water vapor than to CO2.In addition,CoCeOx-70 exhibits excellent stability and reusability in water vapor and CO2 atmosphere.

Synthesis and Crystal Structure of a One-dimensional Mn(Ⅱ) Coordination Polymer with 1,3-bis(4-pyridyl)propane

A new 1D zigzag chain coordination polymer, { [Mn（bpp）（bac）2]·（CHaCN）}n 1 （bpp = 1,3-bis（4-pyridyl）propane, Hbac = benzoylacetone）, has been synthesized and characterized by FT-IR spectroscopy, thermal analysis and X-ray single-crystal diffraction. In the molecular structure, all Mn atoms locate in an octahedral geometry. The guest CH3CN molecules are included in the 1D channels of the 3D packing structure of 1. Crystal data： C35H35MnNaO4, Mr = 616.60, monoclinic, space group P211c, a = 17.691（4）, b = 18,955（4）, c = 9.712（6） A, β = 93.91（3）°, V = 3249.31（1） A^3, Z = 4, Dc = 1.260 g/cm^3, F（000） = 1292, 20max = 54.9°, μ = 0.447 mm^-1, the final S = 1.020, R = 0.0693 and wR = 0.1497.

A New Two-dimensional Zinc Coordination Polymer Constructed by 1,3-Bis(4-pyridyl)-propane and Terephthalate: Synthesis and Crystal Structure

A new zinc coordination polymer, [Zn2（bpp）（tpa）2H2O] 1 （bpp=1,3-bis（4-pyridyl）-propane and tpa=terephthalate） has been hydrothermally synthesized and characterized by elemental analysis, IR and single-crystal X-ray diffraction. X-ray crystal structure analysis reveals that complex 1 crystallizes in monoclinic, space group P2/c with a=18.348（2）, b=10.9080（14）, c=13.7924（18）, β=98.156（2）°, V=2732.5（6）3 , Z=4, C29H24N2O9Zn2 , Mr=675.24, Z=4, F（000）=1376, Dc=1.641 mg/m3 , μ=1.815 mm-1 , the final R=0.0443 and wR=0.0769 for 2715 observed reflections （I〉2σ（I））. The title complex exhibits a two-dimensional （4, 4） sheet structure which is further stacked through face-to-face π-π interactions between the monodentately coordinated pyridine ring of bpp ligand and the phenyl ring of terephthalate ligand to form a 3-dimensional supramolecular structure. Thermogravimetric analyses show that the host framework of the complex is thermally stable up to ca. 400 ℃.

SYNTHESIS OF THE RING—AND SIDE—CHAIN—^(14)C—LABELED 1,2—BIS—(4—MORPHOLINOMETHYL—3,5—DIOXOPIPERAZIN—1—YL) PROPANE

The ring-and side-chain-14C-labeled probimane, 1,2-bis （4-morpholinomethy1-3,5-dioxopiperazin-1-yl） propane were synthesized from acetic acid-1-14C in 4 steps and from 14C-formaldehyde in 1 step respectively. The radiochemical yeild for the ring labeling was 28.1%; for the side-chain labeling was 18.5%.

纳米Co_(3)O_(4)催化剂用于丙烷催化燃烧性能研究

挥发性有机化合物(VOCs)是臭氧和PM2.5的重要前驱体,其排放对环境和人类健康造成极大的危害。催化燃烧是消除VOCs最有效的方法之一。四氧化三钴(Co_(3)O_(4))作为VOCs催化燃烧活性最高的过渡金属氧化物催化剂之一,最有潜力取代贵金属。本文采用不同方法制备三种不同Co_(3)O_(4)纳米催化剂,选择丙烷作为VOCs模型分子,考察Co_(3)O_(4)对丙烷催化燃烧性能。研究表明采用沉淀法制备出的Co_(3)O_(4)表现出最佳的催化活性,其T_(90)仅为251℃,比直接焙烧出来的Co_(3)O_(4)的T_(90)低33℃,这种较高的活性归因于其较大的比表面积、最低的Co^(3+)还原温度、最多的表面Co^(3+)物种以及活性氧物种。随着焙烧温度的增加,使得Co_(3)O_(4)的晶粒尺寸变大,因而其表观活性降低。

Synthesis and Structural Characterization of a New Hydrogen-bonded Polyrotaxane of [Co(H_2O)_6]_(2+) with 1,1′-(Propane-1,3-diyl)dipyridinium-4-carboxylate

A new double betaine 1,1′-（propane-1,3-diyl）dipyridinium-4-carboxylate L has been synthesized. Reaction of 1, 1′-（propane-1,3-diyl）dipyridinium-4-carboxylate tetrahydrate 1 with Co（ClO4）2-6H2O leads to the formation of a new Co（Ⅱ） coordination compound, namely [Co（H2O）6]-2H2O-2L-2ClO4 2. The crystal structures of 1 and 2 have been determined by single-crystal X-ray diffraction method. Crystal data for 1. monoclinic, space group C2/c, a = 18.945（4）, b = 7.700（2）, c = l 1.888（2）A,β = 101.67（3）°, V = 1698.3（6） A^3, Z = 4, F（000） = 760.0, Dc = 1.402 g/cm^3, the final R = 0.0607 and wR = 0.1607 for 950 observed reflections （1 〉 2σ（I））; and those for 2： monoclinic, space group P21/c, a = 17.982（1）, b = 15.879 （1）, c = 7.0716（5）/A,β= 100.675（1）°, V= 1984.3（3） ,A^3 Z= 4, F（000） = 1010.0, Dc = 1.631 g/cm^3, the final R = 0.0316 and wR = 0.0896 for 3784 observed reflections （1 〉20（I））. Crystal structure analysis indicates that in 1, molecules of L in a ＂V-shaped＂ conformation are linked to chains sustained by O-H…O hydrogen bonds between carboxylate groups and solvent water molecules. The chains are joined by O-H…O and C-H…O hydrogen bonds to further expand into a three-dimensional structure. For 2, molecules of L in a ＂Z-shaped＂ conformation are linked by hydrogen bonds between carboxylate groups and aqua ligands to form a chain of loops running down the b axis. The （2D→2D） polythreading in compound 2 represents the mode of parallel interpenetration of 2D sheets, having polyrotaxane character.

Syntheses and Crystal Structures of Cobalt(II) Chloride Complexes of 1,3-Bis(pyridyl-4-ylthio)propan-2-one

Reactions of 1,3-bis（pyridyl-4-ylthio）propan-2-one L and COCl2·6H2O under different conditions gave two new cobalt（Ⅱ）-chloride-L complexes with distinct structures. Complex [Co（L）2Cl2]·0.5CH3OH}n 1 prepared by solvothermal treatment is a 3D network, whereas complex {[Co3（L）2Cl6（DMF）4]·2CH3OH·H2O} 2 obtained in DMF-diethyl ether system is a discrete acyclic trimer. Crystal data for 1： space group lbca, a = 15.993（4）, b = 18.454（5）, c = 21.506（6）A, V= 6347（3） ,A^3, Z = 8, Dc = 1.462 g/cm^3,μ = 1.005 mm^-1, F（000） = 2864, C26.5H26Cl2CoN4O2.5S4, Mr = 698.58, the final R = 0.0499 and wR = 0.1024. Crystal data for 2： space group P1^-, a = 9.9177（6）, b = 11.0871 （4）, c = 15.5490（12） ,A, α = 83.1834（14）,β = 88.910（13）, γ = 71.096（ 11 ）°, V = 1605.8（2） A^3, Z = 1, Dc = 1.362 g/cm^3,μ= 1.194 mm^-1, F（000） = 677, C40H62Cl6Co3N8O9S4, Mr = 1316.71, the final R = 0.0666 and wR =0.1575.

Co_(3)O_(4)/CeO_(2)催化剂上丙烷完全氧化反应中载体性质影响

采用不同制备方法合成不同性质的CeO_(2)载体,并制备负载型Co_(3)O_(4)/CeO_(2)催化剂应用于丙烷完全氧化反应。结果表明,部分CO_(2)+进入CeO_(2)晶格中形成固溶体,改变了CeO_(2)的晶格结构并产生氧空位。氧空位的数量与不同性质的CeO_(2)密切相关,影响催化剂上氧物种的可还原性,从而对反应行为产生影响。其中,以沉淀法制备的CeO_(2)为载体的5Co/CeO_(2)-C催化剂活性最佳(T_(90)=320℃),可归因于该催化剂中较高氧空位浓度导致的最佳低温可还原性。此外,该催化剂还具有良好的稳定性和抗水性能。

2,2-二(4-羟基-3-硝基苯基)丙烷的合成

双酚A经硝化可制得合成阻燃剂的中间体 2 ,2 二 (4 羟基 3 硝基苯基 )丙烷。最佳硝化条件为 :w(HNO3 ) =2 2 % ,反应温度 30℃ ,反应时间 3h ,目标产物的产率最高达到 87 5 %。产物经柱色谱纯化后 ,其元素分析、红外光谱。

2,2-二(4-羟基-3-氨基)苯基丙烷的合成

在乙醇介质中 ,以Fe(OH) 3 /C为催化剂 ,用 80 %水合肼将 2 ,2 二 ( 4 羟基 3 硝基 )苯基丙烷还原为 2 ,2 二 ( 4 羟基 3 氨基 )苯基丙烷。产率 99.0 % ,纯度 98.5 %。考察了 1 0种金属离子对催化剂活性的影响 ,结果发现Pb2 + 会引起催化剂中毒 ;Mg2 + ,Cu2 + 和Zn2 + 钝化了催化剂的催化活性 ;Ba2 + 和Cr3 + 不影响催化剂的活性 ;Al3 + ,Ni2 + ,Ti3 + 和Ti4+ 能活化催化剂 ,使反应速度加快 ,但它们单独使用时无催化活性。

2.2-二(3-氨基-4-羟基苯基)丙烷的合成

用氯化亚锡、锡、浓盐酸和乙醇的还原体系 ,将 2 .2 二 (4 羟基 3 硝基苯基 )丙烷还原为阻燃剂的中间体 2 .2 二 (3 氨基 4 羟基苯基 )丙烷 .产物经重结晶纯化后 ,其元素分析、红外光谱、核磁共振和质谱数据与结构相符 .

2,2-二(4-羟基-3,5-二硝基苯基)丙烷和2,2-二(4-羟基-3-硝基苯基)丙烷的合成

双酚A在不同的w(HNO3 )溶液中硝化可得到不同的产物。在w(HNO3 ) =2 2 %的硝酸溶液中硝化 ,反应温度 30℃所得产物为 2 ,2 二 (4 羟基 3 硝基苯基 )丙烷 ,在w(HNO3 ) =6 3%的硝酸溶液中硝化 ,采用三段温度控制法 (0℃ - 30℃ - 5 0℃ )所得产物为 2 ,2 二 (4 羟基 3,5 二硝基苯基 )丙烷。产物经柱色谱纯化后 ,其元素分析、IR ,1HNMR ,13

多官能环氧树脂/2,2,-双(3-氨基-4-羟基苯基)六氟丙烷体系的固化反应动力学研究

采用差示扫描量热法(DSC)研究了N,N,N',N'-四缩水甘油基-4,4’-二氨基二苯甲烷(TGDDM)与新型含氟固化剂2,2,-双(3-氨基-4-羟基苯基)六氟丙烷(BAHPFP)的固化反应动力学。结果表明:固化反应过程中出现两个明显的放热峰,第一放热峰所对应的反应活化能Ea1为65.7kJ/mol,反应级数n1为0.91;第二放热峰所对应的反应活化能Ea2为120.2kJ/mol,反应级数n2为0.93。

2,2-二(3-氨基-4-羟基)苯基丙烷的合成与结构表征

分别在Pd/C、FeOOH和FeCl3·6H2O/C三种不同催化剂存在下,由水合肼还原2,2 二(4 羟基 3 硝基)苯基丙烷(1)合成了2,2 二(3 氨基 4 羟基)苯基丙烷,筛选出成本低、收率高的理想催化剂为FeCl3·6H2O/C。当物料配比n(水合肼):n(1)=5:1,反应起始温度为70℃,反应时间为80min时,收率为93 0%。产物经重结晶纯化后,由元素分析、红外光谱、核磁共振谱和质谱对其结构进行了表征,确证了产物的结构。

FeCl_3·6H_2O/C催化水合肼还原制备2,2-二(4-羟基-3-氨基)苯基丙烷

以ω(Fe)=5%的FeCl3·6H2O/C为催化剂,用ω(NH2NH2)=80%的水合肼,在乙醇溶剂中将2,2-二(4-羟基-3-硝基)苯基丙烷还原成为阻燃剂的中间体2,2-二(4-羟基-3-氨基)苯基丙烷.实验条件:用0.3g的催化剂(每10mmol反应物),反应物与水合肼的摩尔比为1∶4.5,控制反应温度为70℃,反应时间为3.5h,目标产物的产率为93.0%,纯度为98.5%,考察9种金属离子对催化活性的影响.结果表明:Pb2+会引起催化剂中毒;Mg2+、Cu2+和Zn2+钝化了催化剂的催化活性;Ba2+和Cr3+对反应几乎不影响;只有Al3+、Ni2+、Ti4+3种离子能活化催化剂,从而使反应速度加快,但这3种金属离子单独作为催化剂时都没有催化活性.