氯苄基官能化和氯苄基甲基双官能化介孔分子筛MCM-41的合成与表征

首先比较了氯苄三乙氧基硅烷和氯苄基三氯硅烷硅烷化介孔分子筛MCM-1的差异性,进而采用氯苄基三氯硅烷和甲基三氯硅烷混合试剂硅烷化介孔分子筛,一步得到氯苄基甲基双官能化介孔分子筛MCM-41,并用固体核磁予以证实.发现甲基三氯硅烷一方面可以作为一种“稀释剂”调节氯苄基的负载量,另一方面甲基的引入可增强介孔分子筛的水热稳定性.     

氨丙基官能化HMS介孔分子筛的合成及表征

沿S0I0路径,以十六胺为模板剂,以3-氨丙基三乙氧基硅烷为有机硅源,通过与TEOS共水解沉淀合成了氨丙基官能化HMS介孔分子筛.采用粉末X-射线衍射分析、N2吸/脱附、扫描电镜分析、高分辨透射电镜分析、傅立叶变换红外分析以及元素分析等表征手段,对所合成的材料进行表征.氨丙基官能化HMS介孔分子筛具有worm-like孔道结构,且较为均一的孔径分布.研究了前体硅源中3-氨丙基三乙氧基硅烷含量的变化对氨丙基官能化HMS介孔分子筛的相结构及织构性能的影响.傅立叶变换红外分析表明,NH2-CH2-CH2-CH2有机基团分布在杂化HMS介孔孔道中.     

乙二胺基和2,4-戊二酮官能化介孔分子筛固载钼(VI):新型的环己烯环氧化催化剂

通过对介孔分子筛HMS和MCM 41表面修饰 ,将乙二胺基和 2 ,4 戊二酮引入到介孔分子筛孔道内 ,制备出乙二胺基和戊二酮官能化介孔分子筛 .首次将烯烃环氧化均相催化剂MoO2 (acac) 2 固载到乙二胺基和戊二酮官能化介孔分子筛孔道内 ,制备出新型的、易回收、可重复使用的烯烃环氧化多相催化剂 .环己烯催化环氧化表明 ,该催化剂的催化活性与均相催化剂MoO2 (acac) 2 相当 ,选择性大于 80 %.     

不同硅烷对HMS介孔分子筛甲基接枝的对比研究

通过气相沉积法,分别用三甲基氯硅烷(TMCS)和六甲基二硅氮烷(HMDSZ)对HMS介孔分子筛表面进行甲基接枝改性;分别采用XRD、N2-吸附、FTIR、29SiNMR和TG等手段对样品进行表征,并测定了样品的亲水性能.结果表明,两种硅烷都可以在HMS表面接枝,接枝后分子筛的介孔结构依然保持;但是,HMDSZ的接枝效果...     

苯官能化MCM-41的合成、表征、磺酰化及与二胺的反应

以三乙氧基硅基苯((C₂H₅O)₃Si-Ph，（(triethoxysilyl)benzene，TESB)以及正硅酸乙酯（TEOS）的混合液为硅源，以溴代十六烷基吡啶(CPBr)为模板剂，在HCl介质中合成了苯官能化的有机-无机杂化介孔分子筛MCM-41。对合成的分子筛用FT-IR、PXRD、TEM、N₂吸附-脱附等手段进行了表征。结果表明，合成的苯官能化的有机-无机杂化介孔分子筛具有良好的介孔孔道结构。用三甲基氯硅烷对分子筛表面的Si-OH进行了封端处理，用氯磺酸对合成的苯官能化的有机-无机杂化介孔分子筛进行了磺酰化，并与各种二胺进行了反应。     

氩吸附法研究多级孔分子筛的孔结构

采用不同方法分别制备了双介孔分子筛、介微孔分子筛及介孔沸石材料,利用氩吸附法并结合XRD技术表征了多级孔分子筛的孔结构。探讨了适用于多级孔分子筛的孔径分布计算方法,揭示了不同类型吸附等温线与孔径分布、孔型及孔容等之间的关系。研究表明,对于多级孔分子筛、微孔和介孔的孔径分布分别用SF法和BJH法计算较适宜,全孔分析可用NLDFT法计算。通过对TS-1介孔沸石的孔结构分析发现, TPAOH 在改性制备介孔TS-1的过程中起到了生成介孔及促进二次晶化的双重作用。     

前驱体组装高水热稳定性介孔分子筛MSU-S

采用硅铝基微孔分子筛前驱体,组装合成出高水热稳定性的介孔分子筛MSU-S,并采用XRD、SEM、FT-IR、BET等考察了硅铝基前驱体的晶化时间对MSU-S有序度和水热稳定性的影响.结果表明,利用晶化一定时间的前驱体,可以组装出有序度高、水热稳定性好的介孔分子筛MSU-S,该分子筛经800℃水热处理2 h后,还可以保留完整的介孔结构.     

介孔分子筛MCM-41表面的有机胺功能化及其应用

采用γ-胺丙基三甲氧基硅烷与表面硅羟基的反应,对介孔分子筛MCM-41进行了有机胺功能化.并对其进行了表征.XRD、比表面积测定、元素分析、TG、FT-IR和TEM的测定结果均表明,MCM-41表面成功地接枝上了有机胺功能基团而六方结构特征基本保持.在有机胺功能化的MCM-41上固载Ru基催化剂,并将其用于CO2加H2合成HCOOH反应,所显示的活性优于相应的均相催化剂,并且该催化剂具有较好的回收再用性能.     

微孔-介孔复合结构分子筛的合成及表征研究

以工业现有的ZSM-5作为原料,经一定化学处理的ZSM-5作为部分硅铝源,与介孔分子筛的凝胶在水热条件下进行组装得到具有微孔、介孔双孔分布的复合分子筛,并采用XRD、N2吸附脱附、IR、SEM、TEM等测试手段对合成样品进行分析表征,考察了主要合成条件对分子筛性能的影响.结果表明,合成过程中微孔与介孔结构之间会相互转化,样品中微孔与介孔特征峰存在此消彼长的关系.非临氢反应结果表明,复合分子筛具有较高的异构化选择性.     

MCM—48介孔分子筛的合成研究

利用水热法合成了ＭＣＭ－４８介孔分子筛,通过ＩＲ,ＴＧ－ＤＴＡ,ＸＲＤ,ＸＲＤ,ＴＥＭ,Ｎ２吸附等方法对产物进行了表征,并系统地研究了晶化温度、晶化时间、凝胶组成等对合成ＭＣＭ－４８介孔分子筛的影响。     

浅谈影响循环冷却水浊度的因素

简述了影响辽阳石化硝酸厂循环冷却水的因素。指出影响循环水浊度的主要原因是系统泄漏,提出泄漏带来的危害及应采取的防范措施。     

单笼形水分子簇中心水分子对类型关系

随机产生单笼形水分子簇(H2O)n(n=8~36),经分类统计后发现,在笼形水分子簇中,其1221,1212,2121和2112四类氢键的个数与水分子和氢键总数之间有定量关系,且1212类氢键的个数与2121类的氢键始终相等.如果笼形水分子簇中某一类氢键数已知,则它的其余三类氢键的个数也随即确定.     

Molecular electric properties in electronic excited states: multipole moments and polarizabilities of H2O in the lowest1 B 1 and3 B 1 excited states

Summary The dipole and quadrupole moments and the dipole polarizability tensor components are calculated for the¹ B ₁ and³ B ₁ excited states of the water molecule by using the complete active space (CAS) SCF method and an extended basis set of atomic natural orbitals. The dipole moment in the lowest¹ B ₁ (0.640 a.u.) and³ B ₁ (0.416 a.u.) states is found to be antiparallel to that in the ground electronic state of H₂O. The shape of the quadrupole moment ellipsoid is significantly modified by the electronic excitation to both states investigated in this paper. All components of the excited state dipole polarizability tensor increase by about an order of magnitude compared to their values in the ground electronic state. The present results are used to discuss some aspects of intermolecular interactions involving molecules in their excited electronic states.     

竹炭对饮用水中氟离子的吸附条件研究

研究了竹炭对饮用水中氟离子的吸附能力以及pH值、投料量、吸附作用时间、再生方法、再生效果等因素对除氟效果的影响。结果发现，竹炭对氟具有较好的吸附效果，是较为理想的饮水除氟材料。     

煤质因素对水煤浆性质的影响

采用多元线性回归分析的方法研究了煤质因素对水煤浆成浆性、流变性及稳定性的影响。并采用多元逐步回归分析的方法对影响水煤浆性质的煤质因素进行了综合分析,以确定影响水煤浆性质的主要煤质因素,并建立了相关的经验方程。结果表明,与煤成浆性有关的主要煤质因素为煤的碳质量分数、空气平衡水分、可磨性指数以及压汞仪所测煤的比表面积,复相关系数达0.988;与煤浆流变性有关的主要煤质因素为煤的灰分质量分数、煤中可溶矿物离子的溶出量、压汞仪所测煤的孔体积以及煤表面的动电位性质,复相关系数为0.917;与煤浆稳定性有关的主要煤质因素为煤岩显微组分分析中丝质组分的质量分数和煤灰成分分析中SiO2的质量分数,复相关系数为0.779。     

Quantum-chemical study of structurization of water in the cavity of cucurbit[6]uryl

Structurization of water in the cavity of cucurbit[6]uryl was studied using the highly effective PRIRODA quantum-chemical program package, the PBE functional, and the TZ atomic basis. The structural and energy characteristics of the formation of small water clusters in the cavitand void were calculated. The maximum possible number of molecules in the void was found to be six.     

Dipeptide-catalyzed direct asymmetric aldol reactions in the presence of water

The l-proline-based dipeptide has been discovered and developed as an efficient catalyst for the direct asymmetric aldol reactions of unmodified ketones with various aldehydes including aromatic, aliphatic, heteroaromatic, and unsaturated aldehydes in the presence of water at 0 °C. The resulted methodology and optimal conditions led to the corresponding aldol products with high yields (up to 94%) and good enantioselectivities (up to 97% ee).     

需氯量试验对净水消毒的指导作用

在一定试验条件下，对使用液氯作净水消毒的水进行需氯量试验，所得结果作为加氯量的参考，取得了良好的效果。     

Ab initio study of tautomerism and hydrogen bonding of β-carbonylamine in the gas phase and in water solution

All the possible conformations of the three tautomeric isomers of simple β-carbonylamine were fully optimized at ab initio MP2/6-31G** and B3LYP/6-31G** levels in order to determine the conformational equilibrium and the energies of the O—H···N and O···H—N hydrogen bridges. For the most interesting conformations, further calculations in water solution were also carried out. It was found that carbonylamine is the most stable tautomer, followed by enolimine and carbonylimine. This order of stability does not change in solution. O—H···N is the strongest hydrogen bridge, but in solution its energy as well as that of the O···H—N one are dramatically lowered. The deprotonation energy was also calculated and discussed. Received: 16 September 1999 / Accepted: 3 February 2000 / Published online: 5 June 2000     

Phase equilibria in polymer/solvent systems. Part V: Thermodynamic theory of the swelling pressure equilibrium of a crosslinked substance with a solvent in various phases

A thermodynamic theory has been developed to define the swelling pressure equilibrium between a homogeneous gel and a pure solvent, where phase transitions of the solvent, such as evaporation and crystallization can occur. It is shown that the equilibrium curve, which describes the temperature dependence of the composition in the gel phase under the condition of a constant swelling pressure, has distinct bends at the transition temperatures. These bends are related to the enthalpies of transition of the pure solvent at the transition temperatures. As a consequence of the phase transition of the solvent the swelling pressure-temperature curve at constant composition of the gel shows a discontinuous behavior at the transition point. Numerical calculations with a modified Flory-Huggins expression, based on results of swelling and deswelling measurements of the system crosslinked PEG/water, are presented.The discussion includes natural systems, which are in the gel state, where water may crystallize in the extracellular space.