Catalytic Cracking of Naphtha to Light Olefins

A catalytic process that produces light olefins from naphtha was developed to improve the yield of the conventional steam cracker. In laboratory-scale tests, a newly developed zeolite-based catalyst at a reaction temperature of 650°C produced an ethylene-plus-propylene yield of about 60%, which is about 10% higher than the conventional process operated at around 820°C. A feasibility study carried out for a catalytic cracking process using the developed catalyst, that cracks 3000 tons-naphtha/day, indicated an energy saving of about 20% compared with the conventional process.     

Distribution of Elements among Fractions of Petroleum Tars and Bitumens from West Siberian Industrial Oil

Distribution of C, H, N, S, and O among polar and nonpolar components of malthenes and asphaltenes of initial tars and quality and substandard bitumens obtained from them is studied by chemical and elemental analyses and ¹H and ¹³C NMR.     

汽油中气体组分含量的快速分析

采用美国HP6890炼厂气分析多维填充柱色谱仪,建立了汽油中气体组分含量快速分析方法。采用汽油直接进样,校正归一化法定量,测定汽油中CO2、H2S和各气体烃组分的含量,完成一个样品的分析仅需22min。实验表明,该方法有很好的精密度,各气体组分浓度值的相对标准偏差均小于4．5％。     

Liquid-Vapor Phase Equilibria in Binary and Ternary Subsystems Constituted by Pyrocondensate Components from the Pyrolysis of Straight-Run Naphtha

Liquid-vapor equilibrium in the binary subsystems of the ethylbenzene-o-xylene-α-methylstyrene-p-vinyltoluene-dicyclopentadiene-indene system was predicted using UNIFAC group model and studied experimentally. To assess the reliability of parameters, the liquid-vapor equilibrium was studied experimentally in the ternary systems and compared with the calculated data.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 3, 2005, pp. 403–407.Original Russian Text Copyright © 2005 by Prikhod’ko, Komarova, Gorelova, Gorlova, Bondaletov.     

Continued Fractions and Upper and Lower Bounds in the Brillouin-Wigner Perturbation Scheme

A derivation of approximants to a continued fraction development of the energy is presented. It is based on the techniques of infinite order perturbation theory and inner projection of operators. The approximants have been introduced before; here their formal nature is clarified and conditions under which they exhibit extremal properties are presented. The oscillatory behaviour about the true eigenvalue, observed previously in the Mathieu problem, is explained. Une dérivation des approximations successives pour un développement en fraction continue de l'énergie est presentée. Elle est fondée sur les méthodes de la théorie des perturbations d'ordre infini. Ces approximations sont déjà connues; ici leur nature formelle est clarifiée et des conditions pour qu'ils aient des propietées extrémales sont données. Le comportement oscillatoire autour de la valeur propre exacte, observé auparavant, est expliqué. Es wurde eine Ableitung von Annäherungen einer Entwicklung der Energie in Kettenbrüchen beschrieben. Sie ist auf Methoden der Störungstheorie unendlicher Ordnung gegründet. Diese Annäherungen sind schon früher eingeführt worden; hier wurde ihre formale Natur abgeklärt und Bedingungen, unter welchen sie Extremaleigenschaften besitzen, wurden hergeleitet. Die Schwingungem um den exakten Eigenwert, die früher in dem Mathieuproblem beobachtet worden sind, wurder hier erklärt.     

The Pyrolysis of Azides in the Gas Phase

The chemistry of the non-metallic elements has in recent years passed through a period of rapid development, often referred to as its “renaissance”. To emphasize just one of the key facets: numerous short-lived molecules containing multiple bonds to elements of the third and higher periods have been discovered, often accompanied by the planned synthesis of derivatives which are sterically shielded by bulky groups and thus kinetically stabilized. Thus today molecules such as silabenzenes H₆C_6?nSi_n and silaethenes H₂Si?CH₂ or R₂Si?CR₂, disilenes R₂Si?SiR₂ and diphosphenes RP?PR, silaphenylisonitrile H₅C₆? N?Si, or methylidyne-phosphanes R? C?P, are all well-known species. Sandwich compounds with P₆ rings or silicon centers demonstrate that there are now hardly any barriers to impede the imagination of the non-metal chemist. In sharp contrast is our lack of knowledge regarding the “microscopic” pathways of chemical reactions: thus apart from information provided for example by molecular beam experiments, or from exact numerical calculations involving species consisting of only a few atoms, it remains largely unknown from which directions medium-sized molecules must approach each other to successfully collide and form a “reaction complex”, in which way their structures are changed in such a process or which role is played by molecular dynamics in the energy transfer.–The pyrolysis of azides X? N₃, i.e. compounds which tend to explode violently when ignited in the condensed phase but can be heated in low-pressure gas flow systems without much risk, illustrates that studies of reactive intermediates are of interest not only because novel molecules may be discovered and isolated, and thereby possibilities for synthesis expanded. Moreover, some aspects of the “microscopic” pathways of these azide pyrolyses can be described satisfactorily on the basis of calculated energy hypersurfaces, and the influence of molecular dynamics becomes experimentally visible in the “chemical activation” of intermediates which leads to their “thermal explosion”.     

气相色谱—裂解炉联用分析硅氨烷高温裂解逸出气体

以气相色谱与高温裂解炉联用，对用于制备Ｓｉ－Ｃ－Ｎ微粉的前体「ＳｉＣｘＮｙＨｚ」ｎ在Ａｒ气条件下高温裂解过程中所逸出的ＣＨ４、Ｈ２气体进行了分析。     

Divinyl Sulfoxide: XI. Selective Addition of Carbonodithioate Anions to Divinyl Sulfoxide in the Water-Benzene System

Selective monoaddition of carbonodithioate anions to divinyl sulfoxide gives rise to O-alkyl S-[2-(vinylsulfinyl)ethyl] carbonodithioates [ROC(S)SK, R = Et, Bu; 42–50°C, 6 h, NaHCO₃, aqueous benzene].     

Kinetics of Isothermal Pyrolysis of Iodomethanes in the Gas Phase

The limiting step of the isothermal pyrolysis of gaseous iodomethane (CH₃I → 3/4CH₄ + 1/2I₂ + 1/(4n)C _n ) and diiodomethane (CH₂I₂ → 1/2CH₄ + I₂ + 1/(2n)C _n ) are the reactions 2CHI → C₂ + 2HI and 2CI₂ → C₂ + 2I₂, respectively. The rate constants of these reactions were determined.     

Phosphine-Catalyzed Reactions of Imides and Hydrophosphoryl Compounds Addition to Divinyl Sulfone

Russian Journal of General Chemistry - An efficient method for the phosphine-catalyzed bisaddition of P(O)H compounds and cyclic imides to divinyl sulfone has been developed. The reaction proceeds...     

Changes in the Composition,Structure, and Activity of Catalysts in Hydrogenation of Diene Hydrocarbons of the C5-C9 Fraction of Pyrolysis Naphtha

A comparative study was performed of changes in the composition, structure, and catalytic activity of catalysts in selective hydrogenation of C₅-C₉ fraction of pyrolysis naphtha. The main reasons for catalyst deactivation in the course of industrial exploitation were considered.     

Development and Applications of an Automated In-Column Pyrolysis Gas Chromatography-Mass Spectrometry System

A novel system for sample introduction into a Gas Chromatograph (GC) using an automated in-column pyrolysis device has been developed. The in-column pyrolysis device is suitable for use with any GC or GC-MS system. Solid samples are dissolved or emulsions can be diluted and injected into the system. Because the system is designed for introducing liquid samples, a better control of the injected sample amounts is achieved. This leads to high reproducibility of the peak areas, offering new opportunities for quantitation of polymers or other high molecular weight materials. In addition, a better statistical representation of the material to be analyzed is given if the samples are dissolved in a solvent. The system can be operated both in a normal GC injection mode, and in the pyrolysis mode. As a conventional GC injector working in on-column or Programmed Temperature Vaporization (PTV) injection mode, (without the pyrolysis function), information on the volatile fraction of a sample can be obtained. Once the volatile materials in the sample have been separated, a second analysis on the non-volatile matrix can be performed by initiating the pyrolysis sequence, yielding information on the non-volatile fraction of the sample. Both features, on column or PTV injection mode and in-column pyrolysis can be used separately or in combination. This new technology is expected to be useful for the determination of additives, monomers, solvents and other volatile components in a non volatile matrix, such as polymers, as well as in the characterization of the non-volatile matrix itself, in a single run. Revised: 20 June and 21 July 2005     

热裂解气相色谱-质谱研究阻燃纤维的结构及烟雾毒性

随着高分子材料的不断开发,涌现出一大批用于阻燃和热辐射防护的耐高温纤维,如Basofil、Kermel、visil、Nomex、P84、PBI和PBO等纤维,除了在衣着领域的应用外,在消防服、工业用阻燃防护服以及汽车等的内装饰物和家用防火材料等方面,具有更优异的防护功能和穿着舒适性。在实践中,人们发现有的阻燃纤维织物,虽然有阻燃效果,但在燃烧时烟雾很大,在火灾中有相当一部分人不是被烧死而是窒息死亡;有的阻燃织物燃烧时烟雾密度很低,但含有极毒化合物如HCN,因此研究阻燃纤维的烟雾成分从而研究其毒性具有重要的意义。     

Gas Evolution from the Pyrolysis of Jordan Oil Shale in A Fixed-bed Reactor

Jordan oil shale from El-Lajjun deposit was pyrolysed in a fixed-bed pyrolysis reactor and the influence of the pyrolysis temperature between 400 to 620°C and the influence of the pyrolysis atmosphere using nitrogen and nitrogen/steam on the product yield and gas composition were investigated. The gases analysed were H₂, CO, CO₂ and hydrocarbons from C₁ to C₄. The results showed for both nitrogen and nitrogen/steam that increase the pyrolysis bed temperature from 400 to 520°C resulted in a significant increase in the oil yield, after which temperature the oil yield decreased. The alkene/alkane ratio including ethene/ethane, propene/propane, and butene/butane ratios, can be used as an indication of pyrolysis temperature and the magnitude of cracking reactions. Increasing alkene/alkane ratio occurring with increasing pyrolysis temperature. The alkene/alkane ratio for nitrogen/steam pyrolysis atmosphere was lower than the one found under nitrogen atmosphere. This revised version was published online in July 2006 with corrections to the Cover Date.     

Composition and Microstructure Determination of the Syndiotactic Copolymer of para-Methylstyrene and Styrene by Pyrolysis Gas Chromatography

The composition and microstructure of syndiotactic para-methylstyrene/styrene copolymer was determined by a pyrolysis gas chromatography (Py-GC) method. This method uses the styrene and para-methylstyrene monomer peak intensities to determine the styrene and para-methylstyrene composition in the copolymer. The number average sequence length of styrene was calculated by using the triad peak intensities. Because of the low concentration of para-methylstyrene in the copolymer, the number average sequence length of para-methylstyrene was determined with formulas that incorporate the copolymer composition and the number average sequence length of styrene. The distribution of para-methylstyrene defined by the terms “percent of single units” and “percent of desired distribution” was calculated by the number average sequence of para-methylstyrene. This method has been tested with copolymers containing up to 24 mole% of para-methylstyrene. The composition results from Py-GC of para-methylstyrene and styrene copolymers used in this study were in excellent agreement with ¹H-NMR results.     

热解/红外光谱联用技术用于热解反应的快速检测

详细介绍了快速热解装置CDS2000／红外联用仪(Py／FTIR)的特点。带有样品的热解探头插入并固定在接口装置上，接口装置可直接置于FTIR的光路中，对热解产物进行直接、快速检测，并且可分析重质热解产物。CDS2000热丝裂解器具有极快的升温速度，升温速度从0．01℃／min到20000℃／s，可以有效避免热解过程中的二次反应，有助于推断结构和热解机理；另外，本文对CDS2000／FTIR热解／红外联用仪使用过程中的有关参数进行了分析，如分辨率的选择。本文应用CDS2000／FTIR联用仪对PVC、生物质和模型化合物进行了热解实验，取得了满意的结果。     

气相色谱智能优化在卤代烃分析中的应用

本文研究了气相色谱柱温智能优化软件在卤代烃毒物分析中的应用。智能优化使得包含多个卤代烃与烃的混合样品达到了满意的分离效果，保留值预测误差在１．１％以内，吻合程度很好。