CrOx/ SBA-15介孔催化剂上丙烷在二氧化碳气氛中脱氢反应的研究

The structure and catalytic properties based on Chromium Oxide supported on mesoporous SBA-15 for oxidative dehydrogenation of propane by CO₂ have been studied by using X-ray diffraction (XRD), ultraviolet-visible diffuse reflectance spectra (UV-Vis DRS), electron spin resonance (ESR), X-ray photoelectron spectroscopy (XPS) and propane pulsing experiments in the absence of gas-phase O₂. It has been shown that propane conversion and propene yield increase with Cr loadings. The propane conversion and propene yield on CrO_x(Cr: 10wt%)/SBA-15 catalyst for oxidative dehydrogenation of propane by CO₂ at 550 ℃ reach 24.8% and 21.8%, respectively .The results of ESR, UV-Vis DRS and propane pulsing experiments indicate that Cr^Ⅲ in the CrO_x/ SBA-15 catalyst is the main active species in oxidative dehydrogenation of propane by CO₂ and Cr^Ⅵ, Cr^Ⅴ is inactive in dehydrogenation.     

烯烃歧化催化剂Bu~4N[Mo(CO)~5Cl]-RAlCl~2活性衰减原因的探讨

考察了影响Bu_4N[Mo(CO)_5Cl]-RAlCl_2烯烃歧化催化剂活性的一些因素和反应过程中的动力学行为,并着重讨论催化剂活性衰减的原因。催化剂失活主要是由于形成的金属卡宾活性物种分解所引起。最后分析了烯烃加入顺序对催化剂活性的影响。     

2,2'-二乙炔基-1,1'-联萘为模板构筑的新的环芳化合物的合成及其光学性质

基于2,2'-二取代的联萘衍生物在手性构型上高度稳定的特点,分别以光学活性的(R)-和(S)-2,2'-二乙炔基-1,1'-联萘为模板,设计了2个有趣的拓扑环芳分子四联萘笼状对映异构体(R,R,R,R)-2和(S,S,S,S)-2.其合成路线涉及保护基的控制导入、苯连接桥的链接、保护基的脱去以及偶合成环反应4个步骤.用MS,IR,UV-Vis,1HNMR,13CNMR和元素分析等技术对其进行了表征,并比较了其光学性质.研究结果表明,采用这种模板合成方法能够有效地获得具有单一手性的目标化合物.镜像特征的圆二色(CD)谱和比旋光度[α]D的测定结果清楚地反映了它们的对映异构关系.     

气化炉渣的碱活性研究

目前混凝土骨料资源短缺问题突显,气化炉渣是潜在资源.若采用气化炉渣作细骨料,首先需要判别气化炉渣的碱活性.试验按照砂浆棒快速法研究气化炉渣的碱活性,用三个主要粒级的气化炉渣替代天然砂制作砂浆棒,测定各龄期砂浆棒的长度.试验结果表明天然砂砂浆棒28 d的膨胀率为0.09%,而含有气化炉渣的各组砂浆棒膨胀率均小于0.06%,且0.63 mm粒级是碱硅酸型碱骨料反应的敏感粒级.作为混凝土细骨料使用时,气化炉渣不属于碱活性骨料,反而对碱骨料反应膨胀有一定抑制作用.应用于混凝土时,不必担忧气化炉渣会引起碱骨料反应危害.     

N,N,N′′-三取代氨基甲酰脲类化合物的合成

N，N－二取代脲和取代三氯乙酰胺反应合成了10种未见文献报道的标题化合物，产物结构经元素分析、IR和^1H NMR确证。初步生物活性测定表明多数化合物具有明显的除草活性。     

新型螺环六氢山酮素-氧化吲哚-苯并呋喃酮类拼接物的合成及其抗白血病细胞增殖活性

以色酮-氧化吲哚合成子与3-烯基苯并呋喃酮为原料,在催化剂1,8-二氮杂二环十一碳-7-烯作用下,在二氯甲烷中发生Michael/Michael加成关环反应,合成了6个未见文献报道的螺环六氢山酮素-氧化吲哚-苯并呋喃酮类拼接物(3a^3f),产率75%~87%,dr值3/1~5/1,其结构经1H NMR,13C NMR和HR-MS(ESI-TOF)表征。采用MTT法研究了3a^3f对人白血病细胞(K562)的体外抗增殖活性。结果表明:化合物3c,3e和3f对K562增殖有一定的抑制活性。     

Ab Initio Study on the Anti-HIV Activities of Hydroxyflavones

1 INTRODUCTION AIDS, in other words, Acquired Immunodefici-encysyndrome, is a viral contagious disease withhigh death rate. However, effective treatment againstit has not appeared so far. At present, about 100kinds of natural compounds that could be extractedfrom natural products or artificially synthesized havebeen found to have anti-HIV activities to some ex-tent. They belong to flavonoid, terpenoid, steroid, cou-marin, peptide, alkaloid etc., respectively. Previousstudies show that…     

Theoretical Study on the Antioxidant Activity of Curcumin

The computational results for curcumin at the B3LYP/6-31G(d,p) level show that the enol form of curcumin is more stable than the diketo form because of an intramolecular hydrogen bond, which extends the conjugation effect in the enol chain, formed in the enol structure. Cis-diketone form can not be obtained, presumably due to the strong repulsion between the carbonyl dipoles aligned in parallel. According to the phenolic O-H bond dissociation enthalpy, curcumin in its most stable form can be suggested to be a relatively good antioxidant. In order to avoid overcoming H-bond interaction and to improve the antioxidant activity of curcumin, a catechol moiety was incorporated into curcumin for designing a novel antioxidant. It is found that the designed molecule is much more efficient to scavenge radical than curcumin, comparable to vitamin E. Moreover, the ionization potential of the designed molecule is similar to that of curcumin, indicating that the designed molecule can not display the prooxidant effect.     

2-甲基-6-对甲苯基-1,6-庚二烯的合成

以对甲苯乙酮(1)为原料,经烯醇硅醚化,Lewis酸催化Michael加成反应和Wittig反应,合成了新倍半萜烯化合物2-甲基-6-对甲苯基-1,6-庚二烯。