MnO2/γ-Al2O3催化尿素与1,2-丙二醇合成碳酸丙烯酯

以γ-Al2O3为载体,采用超声浸渍法制备了MnO2/γ-Al2O3催化剂,结合X射线衍射、X射线光电子能谱和CO2程序升温脱附的表征,考察了催化剂对尿素与1,2-丙二醇合成碳酸丙烯酯反应的影响。结果表明,以Mn(NO3)2为锰源经焙烧后形成的MnO2表面碱性最强,对尿素醇解反应的活性最高;采用超声浸渍法,当Mn在γ-Al2O3上的负载量(质量分数,下同)为30%时,Mn在γ-Al2O3表面主要以Mn4+的形式存在,且分散度高,催化剂表面的碱中心的碱性最强。当其催化尿素醇解时,碳酸丙烯酯收率达65.0%。     

催化剂MnyCezOx/Al2O3催化氧化乙酸乙酯的性能

采用浸渍法制备了Mn基负载型催化剂,测定了它们催化氧化乙酸乙酯的活性以及水蒸气对其催化性能的影响,研究结果表明所制备的催化剂对乙酸乙酯都具有明显的催化活性,其中催化剂Mn0.8Ce0.2Ox/Al2O3催化氧化乙酸乙酯的活性最高,其T90仅为225℃。催化剂Mn0.8Ce0.2Ox/Al2O3的抗水蒸气影响的能力也要高于催化剂MnOx/Al2O3。     

CoTiO_3/堇青石催化剂催化KBH_4水解析氢性能研究

堇青石(2Mg O2·Al2O3·Si O2)比表面积高、规整性强,以此为载体,涂敷Ti O2后,通过水热合成负载氯化钴,然后经过500℃焙烧及硼氢化钾(KBH4)浸渍,合成了负载型Co Ti O3/堇青石催化剂。利用X射线衍射(XRD)及X射线光电子能谱(XPS)对催化剂进行表征。催化实验研究表明,该催化剂经KBH4溶液浸渍后催化KBH4溶液水解析氢性能优良。     

Pd-Co/Hopcalite混合氧化物催化苯酚氧化羰基化合成碳酸二苯酯的研究

以Hopcalite氧化物作为载体,浸渍后得到Pd-Co/Hopcalite混合氧化物负载型催化剂,用于氧化羰基化合成碳酸二苯酯(DPC)。通过扫描电子显微镜(SEM)、X射线衍射(XRD)和X射线光电子能谱(XPS)对催化剂进行表征,结果表明:催化剂颗粒大小均匀,具有良好的孔结构;稳定晶相Cu Mn2O4、Co Mn2O4和Pd0.5Pd3O4的形成使反应前后催化剂表面活性组分Mn、Co的价态保持不变,有利于催化剂的重复使用;Pd0.5Pd3O4产生晶格缺陷,增加了晶格中的氧空位,可促进气相氧的吸附,加速整个催化循环,有利于活性组分再生,催化活性进一步提高。通过合成实验,DPC收率和选择性分别达到43.5%和99.6%。     

浸渍方法对CuO-CeO_2/Cord.整体式催化剂性能的影响

用20%的草酸溶液预处理大小适当的堇青石载体,采用分步浸渍法与共浸渍法分别制备了Cu OCe O2/Cord.整体式催化剂。利用气相色谱仪对催化剂的性能进行了测试,并且利用X射线衍射(XRD)等技术手段对样品进行了表征。结果表明,采用共浸渍法制得的催化剂活性更优,且催化剂的选择性在150℃时仍能达到90%。     

甲烷联合重整反应镍基尖晶石催化剂的制备与性能

采用传统浸渍法和溶胶凝胶法分别制备了Ni/MgAl2O4催化剂,并采用氢气程序升温还原(H2-TPR)、X射线衍射(XRD)、透射电镜(TEM)和程序升温脱附(TPD)对催化剂进行表征,考察了催化剂在甲烷联合重整(CSCRM)反应中的催化性能.结果表明:与传统浸渍法制得的Ni催化剂相比,采用溶胶凝胶法制备的Ni/MgAl2O4催化剂中Ni物种与载体之间的作用力更强,在CSCRM反应中表现出更高的催化活性和稳定性.进而,基于溶胶凝胶法探究了Ni/MgAl2O4催化剂中Ni负载量对反应性能的影响,探讨了溶胶凝胶法制备的Ni/MgAl2O4催化剂的构-效关系,为CSCRM反应的非贵金属Ni基催化剂设计与优化提供借鉴.     

H3PW12O40-TiO2/SiO2超声光催化降解罗丹明B的研究

以硅胶为载体,采用浸渍法制备了H3PW12O40-TiO2/SiO2催化剂.通过对染料罗丹明B的超声光催化降解,探讨了催化剂的组成、用量、酸度、催化剂重复使用次数等因素对罗丹明B降解率的影响.结果表明:含4gH,PW12O40的TiO2溶胶浸渍在11gSiO2上的催化效果最佳.催化剂最佳用量为0.2g.初始罗丹明B溶液的pH为1时,反应速率最快.催化剂经活化处理后,重复使用6次,对罗丹明B的降解率仍达95.65%.相同条件下比较H3PW12O40-TiO2/SiO2和TiO2/SiO2对罗丹明B的降解效果发现,H2PW12O40可显著提高TiO2超声光催化降解罗丹明B的降解率.     

超重力法制备Cu-Mn/ZSM-5催化剂及其催化燃烧甲苯的研究

ZSM-5分子筛负载复合过渡金属催化剂(Cu-Mn/zeolite)兼具分子筛和复合过渡金属的双重优势,在催化燃烧消除VOCs领域具有良好的催化性能。通过超重力技术制备了ZSM-5负载复合过渡金属催化剂,系统地研究了超重力环境下制备的Cu-Mn/ZSM-5催化剂的催化活性,并与传统浸渍法制备的催化剂进行比较。通过BET比表面积测试法、X射线衍射、程序升温还原、扫描电子显微镜和X射线光电子能谱分析等技术对催化剂进行表征,结果表明,超重力法制备的催化剂具有更高的催化活性,活性组分在ZSM-5上均匀分散,且负载量较高。     

MnK/Al2O3催化苯甲醇液相氧化制苯甲醛

采用共浸渍法制备Mn1K1/Al2O3催化剂,并以分子氧为氧化剂考察了其在苯甲醇液相氧化制苯甲醛反应中的催化性能。实验结果显示,焙烧温度和负载量对催化剂性能有重要影响,773 K焙烧的10%(wt)Mn1K1/Al2O3具有最高的催化活性,373 K下反应3 h时,苯甲醇转化率为72.9%,苯甲醛选择性为99%,且该催化剂可循环使用6次以上而其催化活性无明显降低。粉末X射线衍射(XRD)、N2物理吸附、拉曼光谱、X射线吸收光谱(XAS)、程序升温还原(H2-TPR)结果表明,负载在Al2O3表面的非晶态或小晶粒α-Mn O2是催化活化分子氧发生醇氧化反应的高活性物种。     

钴锰整体式催化剂的电沉积法制备及NO催化氧化性能

整体式催化剂性能高效、应用广泛,而制备方法是影响其性能的关键因素,因此探究简单高效的制备方法对整体式催化剂的工业应用至关重要。本研究以碳纤维布为载体,采用电沉积方法制备了一系列钴锰整体式催化剂,在固定床反应装置上考察了其催化氧化NO性能,并借助拉曼光谱仪、X射线衍射仪和扫描电镜等分析技术对催化剂进行表征。结果表明,采用电沉积法制备的钴锰二元催化剂比相同方法制备的氧化钴或氧化锰一元催化剂的粒径小,且钴锰比例对催化剂粒径影响很大,最小粒径为3～4nm。不同摩尔比例的钴锰二元催化剂焙烧之后物相差别较大,Mn/Co较高的催化剂的主要组成为Mn₃O₄,Mn/Co较低则趋向Co₃O₄,其中Mn/Co=2时,催化剂为(CoMn)(CoMn)₂O₄。电沉积法制备的钴锰整体式催化剂催化氧化NO的性能要远优于相同方法制备的氧化锰催化剂,在50℃下转化率均接近100%。     

多卤代吡啶选择性合成醚类的反应

以KOH为碱,DMSO为溶剂,在空气中,温度为50℃的条件下,多卤代吡啶和苯酚类化合物反应,形成相应的醚类化合物,该反应具有很好的收率以及区域选择性,是一种有效构建C-O键的方法;以K_2CO_3为碱,DMSO和H_2O为溶剂,在空气中,室温下,多卤代吡啶和苯硫酚类化合物反应,形成相应的的吡啶硫醚化合物,该反应也具有很好的收率以及区域选择性,是一种有效构建C-S键的方法。     

Electronic Structure and Properties of the O2+2, SO2+ and S2+2 Diatomic Dications

Multiply charged ions show novel energetic features which can potentially have useful photophysical properties. In order to investigate these interesting type systems, energy interaction curves for the ground and excited electronic states of O²⁺₂, SO²⁺, and S²⁺₂ have been generated by the ab initio complete active space multiconfiguration self-consistent field (CAS-MCSCF) method. The calculations were carried out in a triple-zeta sp plus double-zeta d Gaussian function basis set using compact effective potentials to replace the core electrons. In order to gauge the accuracy of the results, analogous calculations were carried out on the valence isoelectronic N₂ and NO⁺ systems for which experimental information is available for comparison of geometric and spectroscopic properties. Diverse high energy spectroscopy experiments on O²⁺₂ are interpreted and reconciled using the calculated ground and excited state energy interaction curves. Special attention is paid to the ₃Σ₊^u state, whose location and character have been particularly puzzling. Almost all the dication molecular states studied show the characteristic avoided crossing of diabatic states which gives a trapped equilibrium structure and a barrier to dissociation. These features make the dication kinetically stable, but thermodynamically unstable with an exothermic dissociation energy. The spectroscopy experiments on O²⁺₂ show that these states are experimentally attainable.     

生产乙炔对电石的要求及乙炔清净

目前国内外乙炔大部分仍是由电石制得。然而由于工业电石除CaC2 外还含有很多杂质 ,所以生产乙炔不仅要求电石的纯度、粒度 ,还要求水温。一般电石的块度采用 8～ 2 5mm ,发生器温度控制在 85± 5℃ ,乙炔气体中含H2 S、H3 P、NH3 等气体会使氯乙烯合成氯化催化剂活性下降。因此 ,必须对乙炔气体进行清洁。采用次氯酸钠液体的氧化性将乙炔中的杂质氧化成酸性物质而除去。     

Thermal Expansion of HfO2 and ZrO2

The thermal expansion of a low symmetry crystal can be much more interesting than the lattice parameter expansion would suggest. Here, the complete thermal expansion tensors for monoclinic and tetragonal phases of ZrO₂ and HfO₂ have been measured in air, by high‐resolution, high‐temperature X‐ray diffraction. These results reveal the highly anisotropic nature of thermal expansion in the monoclinic phase as well as a cooperative movement of ions and the existence of a zero thermal expansion plane.     

Separation and purification of aflatoxins B1, B2, G1 and G2, and comparison of semi-synthetic aflatoxins B2 and G2 with naturally-occurring aflatoxins B2 and G2

A method is described for the isolation of highly purified aflatoxins B₁, B₂, G₁ and G₂ from extracts ofAspergillus flavus. The four aflatoxins, isolated from background impurities by rapid passage of the extracts through an acid alumina column, are separated from each other by chromatography on a silica gel column. Aflatoxins B₂ and G₂ are prepared by hydrogenation of the mixture of aflatoxins B₁, B₂, G₁ and G₂ and then separated by elution from a silica gel column with chloroform containing 0.7% ethanol. A comparison of semi-synthetic aflatoxins B₂ and G₂ with naturally-occurring aflatoxins B₂ and G₂ shows no significant difference in physical properties. Presented at the AOCS-AACC Meeting, Washington, D.C. April, 1968.     

Melting and dilatometric behavior of 2-Oleopalmitostearin and 2-Oleodistearin

The glycerides, 2-oleopalmitostearin and 2-oleodistearin, which are important components of confectionery fats, were synthesized, and their melting behavior and dilatometric properties were determined. Each glyceride was found to have four melting points: 18.2, 24.5, 33.0, and 37.4°C, for 2-oleopalmitostearin; 22.8, 30.0, 37.7, and 42.8°C, for 2-oleodistearin. The rate of transformation of the thermodynamically unstable polymorphs at temperatures just below their melting points was found to vary from a few seconds to more than eight days. For each glyceride, expansivities were determined for three polymorphs and melting dilations for two polymorphs. Mixtures of the two glycerides were examined dilatometrically and found to behave in some respects as single components. The mixtures were readily tempered so that both components were in the same polymorphic form, and expansivities and melting dilations were obtained for mixtures in three polymorphic forms. Dilatometric data also were obtained for a sample of cocoa butter and a sample of sweet milk chocolate of the coating type. Presented at the 32nd Fall Meeting, American Oil Chemists’ Society, Chicago, Ill., October 20–22, 1958. Fellow, National Confectioners’ Association. One of the laboratories of the Southern Utilization Research and Development Division, Agricultural Research Service, U. S. Department of Agriculture.     

纳米TiO2和微米SiO2改性及分散性能的研究

采用不同的分散工艺和改性剂对纳米TiO2和微米SiO2粉体进行处理,使用激光粒度仪、红外光谱(IR)、热失重(TG)等手段对粉体粒径,粉体表面结构进行表征,探讨了超微粉体在乙二醇(EG)中分散的最佳工艺.结果表明:钛酸酯偶联剂(NDZ-201)可在纳米TiO2表面接枝,接枝率约为6%;硅烷偶联剂(KH570)可在微米S...     

氢氧直接合成法制过氧化氢技术进展

氢气和氧气直接合成过氧化氢是典型的原子经济性反应，因过程简单、产品清洁、生产成本低而成为催化领域研究开发的一个热点。总结了该法近年来在催化剂活性组分的选取及载体方面的进展；详细介绍了溶剂的选取和反应机理；讨论了各种反应器的安全性。指出今后的研究重点是提高氢气利用率、开发新型的反应器、提高过程的安全性。     

Eu~(2+)掺杂SrSi_2O_2N_2和Sr_(0.37)Ba_(0.60)Si_2O_2N_2荧光粉的发光性能及应用

采用高温固相法合成Sr_(0.97)Eu_(0.03)Si_2O_2N_2和Sr_(0.37)Ba_(0.60)Eu_(0.03)Si_2O_2N_2荧光粉,通过X射线衍射、激发光谱、发射光谱及转换后LED器件的性能等研究了荧光粉的结构、发光性能和稳定性。结果表明:在稀土Eu2+掺杂的Sr Si2O2N2荧光粉中,当部分Sr2+被Ba2+取代后,形成三斜晶系的Sr_(0.37)Ba_(0.60)Eu_(0.03)Si_2O_2N_2荧光粉,激发和发射光谱红移,在近紫外-蓝光区具有更高的激发效率。将2种荧光粉与Ga(N)In芯片封装,Sr0.37Ba0.60Eu0.03Si2O2N2荧光粉转换的白光LED器件,在光效、显色指数和光效维持特性方面均高于Sr_(0.97)Eu_(0.03)Si_2O_2N_2转换的LED器件。     

三氟乙醇的生产和应用前景

介绍了三氟乙醇的性质，生产方法和应用前景。