FT合成沉淀Fe／Cu／K催化剂有效因子的计算Ⅰ．工业颗粒催化剂有效因子的计算

用包括水抑制作用的动力学方程，根据建立的反应扩散模型和ＦＴ合成化学计量关系，计算了工业原颗粒ＦＴ合成沉淀Ｆｅ／Ｃｕ／Ｋ催化剂在工业操作条件下的有效因子。根据不同的产物组成，建立了三种化学计量关系式，比较了气相反应和气液反应的有效因子，确立了ＦＴ合成沉淀Ｆｅ／Ｃｕ／Ｋ催化剂有效因子的计算方法。在ＦＴ合成反应条件下，产物蜡充满了催化剂的微孔，各组分在蜡中的扩散系数要比纯气相中的扩散系数小得多。在工况操作条件下（５２３Ｋ，２．５ＭＰａ，５００ｈ￣（－１），尾气循环比３．０），工业原颗粒（ｄ＿ｐ＝２．５ｍｍ，ｌ＿ｐ＝５～１０ｍｍ）催化剂的实际有效因子是纯气相反应的一半左右，计算的平均有效因子分别为０．４０和０．４２。     

Shortcut method for evaluation and design of a hybrid process for enantioseparations

Hybrid processes for enantioseparations have a considerable potential for reducing investment and operational costs. An example is the combination of simulated moving bed (SMB) chromatography and selective crystallisation. However, the design of integrated processes is a difficult task. A shortcut method is presented that can serve as a tool for design and estimation of the potential of such processes. The approach requires only limited experimental data and thus allows for systematic parameter studies. The method is based on the determination of the purity-performance characteristic of the SMB process and rigorous application of mass balances. The use of relative mass fluxes allows derivation of simple algebraic expressions for essential process parameters. The significant potential of combining SMB and crystallisation is demonstrated for the example of the separation of mandelic acid enantiomers.     

INTRAPARTICLE DIFFUSION EFFECTS IN FISCHER-TROPSCH SYNTHESIS Ⅰ. MODELING OF DIFFUSION AND REACTION

IntroductionCatal}ticrcactionsaffcctcdb}'diffosionaIlimitationincatal}'stporcshavcbccnextensive1}dcaltx`ithinlit.rat.rcll~5I.Scvcraltcchniqucsonthcspccialcase0fFischcr-Tropschs}'nthcsis(FTS)t\crcapplicdtocxplorcthebchaviorofthiscatal}ticrcactionundercxpcrimcntalandopcrationaIconditionsI3~5l.It`"ouldbeofvaluctoindicatchcrcthatthcseinvcstigationsx"ercmainl}'bascdonthesimplcstkineticsofthcfirstordcrinH2proposedbyAndersonl6]attheearIystages.However-thesetboents,striCtlyspeaking,areinvalidfor…     

Infrared Spectroscopy and Structure of Trigonal Zirconium Orthophosphates with Lanthanides and Actinides

Binary zirconium orthophosphates R_1/3Zr₂(PO₄)₃ and M_1/4Zr₂(PO₄)₃, where R = Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu; M = Th, U, have been synthesized and studied by IR spectroscopy [structural family of NaZr₂(PO₄)₃ (NZP)]. Vibrational analysis for the PO₄ tetrahedron and investigation of symmetry relations among trigonal NZP phases showed that ordering of lanthanide atoms in structures of NaZr₂(PO₄)₃ type with space group R c leads to symmetry reduced to P c. The lanthanide atoms occupy the 2b sites. The phosphorus atoms occupy two independent sites: 6f with C ₂ symmetry and 12g with C ₁ symmetry. Factor group analysis admits that the IR spectrum can contain eight v₃ bands and two v₁ bands of the stretching vibrations of the PO₄ ions. The M atoms of actinides occupy statistical positions in the structure, and space group R c is retained.Original Russian Text Copyright © 2004 by V. S. Kurazhkovskaya, D. M. Bykov, and A. I. Orlova__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 6, pp. 1013–1019, November–December, 2004.     

表皮生长因子受体和抑制剂之间分子对接的研究

研究了表皮生长因子受体(EGFR)和4-苯胺喹唑啉类抑制剂之间的相互作用模式，表皮生长因子受体的三维结构通过同源蛋白模建的方法得到，而抑制剂和靶酶结合复合物结构则通过分子力学和分子动力学结合的方法计算得到。从模拟结果得到的抑制剂和靶酶之间的相互作用模式表明范德华相互作用、疏水相互作用以及氢键相互作用对抑制剂的活性都有重要的影响，抑制剂的苯胺部分位于活性口袋的底部，能够与受体残基的非极性侧链产生很强的范德华和疏水相互作用，抑制剂双环上的取代基团也能和活性口袋外部的部分残基形成一定的范德华和疏水性相互作用，而抑制剂喹唑啉环上的氮原子能和周围的残基形成较强的氢键相互作用，对抑制剂的活性有较大的影响，计算得到抑制剂和靶酶之间的非键相互作用能以及抑制剂和靶酶之间的相互作用信息能够很好地解释抑制剂活性和结构的关系，为全新抑制剂的设计提供了重要的结构信息。     

The static dielectric constant of solutions of water inn-alcohols at 15, 25, 35, and 45°C

Dielectric constants (measured at 1 MHz) are reported for solutions of water (concentration range 0 to 0.2 mole fraction) in 1-propanol at 25°C, and in 1-butanol, 1-pentanol, and 1-hexanol at 15, 25, 35, and 45°C. These results, together with literature values for solutions of water in methanol, ethanol, 1-heptanol, and 1-octanol, show that water interacts with alcohols in at least two ways: (1) it can participate in the formation of dynamic hydrogen-bonded chains, thereby raising the polarizability; (2) it can form relatively stable structures such as H₂O(ROH)₄ which have zero net dipole moment and consequently diminish volume polarizability. For C _n H _2n+1 OH alcohols,n≥4, most of the initially added water forms complexes: consequently, addition of water to these alcohols lowers the dielectric constant.     

Interaction of blockcopolymer micelles as probed by small-angle neutron and by small-angle X-ray scattering

 The analysis of the interaction of micelles formed by a blockcopolymer is given by means of small-angle X-ray (SAXS) and small-angle neutron scattering (SANS). The blockcopolymer consists of poly(styrene) and poly(ethylene oxide) (molecular weight of each block: 1000 g/mol) and forms well-defined micelles (weight-association number: 400, weight-average diameter: 15.4 nm) in water. The internal structure has been studied previously (Macromolecules 29:4006 (1996)) by SAXS. There it has been shown that the micelles are spherical objects. The structure factor S(q) as a function of the scattering vector q (q=(4π/λ) sin (θ/2); λ: wavelength of the radiation in the medium; θ: scattering angle) can be extracted from both sets of small-angle scattering data (SANS: q≤0.4 nm^-1; SAXS: q≤0.6 nm^-1). It is shown that particle interaction in the present system can be described by assuming soft interaction which is modeled by a square-step potential. Received: 12 May 1997 Accepted: 9 July 1997     

Dissociation of Fumaric Acid: Spectrophotometric Investigation in Aqueous Solutions from 10 to 90 <Superscript>∘</Superscript>C and Theoretical Considerations

The dissociation constants of fumaric acid were extracted from UV-vis spectra in the 10–90 ^∘C range. These values were used to extract thermodynamic parameters that showed the temperature effects on the dissociations reactions to be dominantly driven by the solvent. The molar absorption coefficients for the fumaric acid, the bifumarate and fumarate species, can be accurately reproduced with the two-term Gauss–Lorentz equation. Deconvolution of these bands showed strong π–π^∗ transitions for all species and weaker charge-transfer-to-solvent transitions for the charged species. TD-DFT calculations were used to identify the most important molecular orbitals involved in the vertical excitations of the fumaric acid species. The electron population and their states of delocalization were also estimated with topological analyses of the electron density and of the Becke–Edgecombe Electron Localization Function.     

Description of the Structure and Properties of Atactic Polystyrene Melt Using Integral Equation Theory

The polymer reference interaction site model （PRISM） integral equation theory was used to describe the structure and thermodynamic properties of atactic polystyrene （aPS） melt, in which the monomer of aPS is represented with an eight-site model to characterize its microstructure. The intramolecular structure factors needed in the PRISM calculations were obtained from single chain MD simulations. The calculated results indicate that the results by the integral equation method agrees well with experiments, and can reflect the fine microscopic structure of real aPS melt. This work shows that the PRISM theory is a powerful tool for investigating the structure and properties of complex polymers.     

New (1R,4R)-2-arylidene-p-menthan-3-ones with a bridging ester group in the arylidene fragment. Synthesis and behavior in liquid-crystalline systems

(1R,4R)-2-(4-Hydroxybenzylidene)- and (1R,4R)-2-(4"-hydroxybiphenyl-4-yl)methylene-p-menthan-3-ones were synthesized by condensation of (–)-menthone with O-tetrahydropyran-2-yl derivatives of 4-hydroxybenzaldehyde and 4"-hydroxy-4-formylbiphenyl, respectively, in a DMSO—base medium followed by the removal of the protective group. The reactions of these hydroxy derivatives with 4-alkylbenzoic, 4-alkyloxybenzoic, trans-4-alkylcyclohexane-4-carboxylic, and 4"-alkylbiphenyl-4-carboxylic acids afforded three series of new chiral esters. Compounds containing the arylidene moiety with three benzene rings were found to exhibit liquid-crystalline properties. The characteristic features of these compounds are discussed based on the results of studies by polarizing microscopy, differential scanning calorimetry, and small-angle X-ray scattering. It was found that the mesomorphic compounds under study can form a smectic A mesophase, twist grain boundary mesophases (TGBA), and blue phases in a wide temperature range. Upon dissolution of certain of chiral compounds in 4"-cyano-4-pentylbiphenyl, a rather high twisting power and the thermal stabilizing effect on mesophases were observed.