Porphyrins of Sakhalin crude oils

• 1.1. The quantitative distribution and the composition of porphyrins in North Sakhalin crude oil were examined. The concentration of vanadylporphyrins was shown to decrease and the content of nickel complexes in crude oils was shown to increase in southerly and westerly directions.
• 2.2. All the crude oil examined had similar vanadylporphyrin structural-group composition.
• 3.3. Sakhalin crude oils differ from those in Western Ekhabi in the relative content of porphyrin isomers most likely to be retained in ivnerted-phase chromatography (molar mass values 487, 501 and 515).

     

N-2-pyridyldialkylthioamides as additives to lubricating oils

• 1.1. New compounds — N-2-pyridyldialkylthioamides — have been synthesized.
• 2.2. These compounds are effective anticorrosion additives to M-11 oil and in this respect are superior to additive ABS-2 (a compound of similar structure) and equivalent to thioformpiperidine.
• 3.3. N-2-Pyridyldialkylthioamide has greater antiscuff properties than thioformpiperidine and additive ABS-2.
• 4.4. Increase in the number of thiocarbonyl groups (C=S) in the thioamide molecules leads to an improvement in their antiscuff properties.

     

Distribution of vanadium and vanadyl porphyrins in petroleum distillates of different chemical types

• 1.1. The greater part of atomic vanadium and vanadyl porphyrin molecules present in crude oils from all producing layers of the Samotlor deposit is concentrated in the petroleum resin, although the absolute concentration of V is maximum in asphaltene fractions. Vanadium atoms associate mainly with hetero-aromatic fragments of crude oil resin-asphalt substances. Up to 98% vanadium is contained in asphaltenes and almost all V atoms in petroleum fractions are contained in non-porphyric compounds.
• 2.2. Using Samotlor crude oils a clear is observed with: a) a reduction in overall vanadium concentration in all fractions, b) in the content of vanadyl porphyrins in malthene fractions, c) according to the paraffinicity of crude oils, particularly in relation to intensification of catagenic transformations with increasing depth and age of the surrounding deposits.

     

Structural features of vanadyl porphyrins of petroleum of West Kazakhstan

• 1.1. Homologous of two main series: alkylporphyrins and monocycloalkylporphyrins are present in vanadyl porphyrins of petroleums of West Kazakhstan.
• 2.2. Vanadyl porphyrins of petroleums of Karazhanbas, Arman and Zhalgyz-Tyube deposits and subsalt petroleums of the Western (near Caspian Sea) region contain cyclic substituents attached to porphyrin rings: two five-membered rings, or benzene and a five-membered ring.
• 3.3. Spectroscopic and thermodynamic investigations of vanadyl porphyrins enabled the presence of two structural groups to be established: monomesoetioporphyrins and desoxophylloerythroetioporphyrins.

     

Study of the chemical nature of petroleum components of high molar mass from Russian fields

• 1.1. Adsorption chromatography on wide-pore adsorbent-Silochrome-was used to segregate components of native petroleum asphaltenes into fractions with very different oxygen and sulphur contents, average molecular weights and aromaticity.
• 2.2. Russian petroleum resin molecules contain aromatic (tri- or tetracyclic on average) blocks containing one or more nitrogen atoms. Polar substances which form the main part of resins contain long, slightly branched aliphatic chains. Low-polarity compounds form a smaller proportion of resin components, their molecules probably contain large, polycyclane fragments which are not condensed with aromatic nuclei.
• 3.3. Asphaltene components, on the whole, are more aromatic than the resinous components and independent of the molar mass of the fractions, contain aromatic nuclei of similar average dimensions, differing mainly in the number of such nuclei in molecules.

     

Petroleum isoprenanes with a non-regular “head-to-head” link

• 1.1. A homological series of C₂₉-C₃₉ isoprenanes having a non-regular “head-to-head” link has been found in oil of the North-Tol'kin field (West Siberia). The structure of the hydrocarbons has been demonstrated by chromato-mass spectrometry and synthesis of a standard C₃₃ hydrocarbon.
• 2.2|It has been shown that the hydrocarbons under examination were formed by means of bacterial combination of pristane radicals and different regular C₁₀-C₂₀ isoprenoids.
• 3.3|The mass spectra and retention indices of the isoprenanes identified are given.

     

High-boiling arenes of Paleozoic petroleum of West Siberia

• 1.1. Thin-layer chromatography and mass-spectrometric analysis established the presence of 15 isobaric-homologous series of aromatic hydrocarbons and 5 series of sulphur-aromatic compounds in fractions from Maloich petroleum. Overall concentrations of arenas in this petroleum show a regular reduction with the increase of the number of aromatic and (with the same aromaticity) napthenic rings in molecules.
• 2.2. Molar mass distributions of monocyclo-aromatic hydrocarbons in Maloich petroleum are characterized by the presence of broad plateau-like maxima in the range of C₁₂-C₂₄. Distributions of members of the remaining arene series are unimodal, maxima in these distributions are more clearly expressed and are usually due to hydrocarbons with three-to-six carbon atoms in alkyl substituents.
• 3.3. The general hydrocarbon type of the system is reflected by the group composition of petroleum arenes, which are enriched in alkyl-aromatic compounds in paraffinic petroleums and in napthenic aromatic compounds, in naphtenic petroleums.

     

Carbazoles of Surakhan crude oil

• 1.1. A carbazole concentrate was separated from the acid extract of a heavy residue b.p.>350°C of Surakhan crude oil by thin-layer and adsorption chromatography on silica gel.
• 2.2. Carbazole, C₁–C₆-alkylcarbazoles, C₁–C₄-alkylbenzocarbazoles and C₁–C₂-alkylphenylcarbazoles were identified by GC MS in the sample separated.

     

Microelements in chromatographic fractions of petroleum resins and asphaltenes from Russian crude oil

• 1.1. Neutron-activation analysis was used to determine 13 microelements in resin-asphalt components of Russian petroleum and products of extraction-chromatographic separation. The concentration of almost all microelements is much higher in asphaltenes than in resins. Vandium atoms are concentrated mainly in non-porphyrinic molecules with moderate polarity and increased aromaticity; during chromatographic separation the other micro-elements accumulate mainly in high-polarity fractions of increased oxygen and sulphur contents.
• 2.2. Fe- and Na-containing components of Russian petroleum are of low stability and easily break down on contact with the active surface of adsorbents; as a result 77–98% of these elements are eliminated from the organic phase during chromatograpy. V, Ag, Hg, Mn, Ni, Co and Zn form much stronger complexes with asphaltenes and resins; some 70% are retained in compounds of high molar mass after adsorption.

     

Study of the structure of petroleum bitumens by the electrical conductivity method

• 1.1. By the measurement of electrical conductivity information may be obtained about the structure and properties of residual petroleum products, in spite of the presence in the latter of conducting impurities.
• 2.2. Using electrical conductivity rheological properties or tar oil and bitumen may be evaluated, structural transitions examined and the degree of ordering of the system and the degree of oxidation, controlled.

     

Experimental particle size distributions and their representation by log—hyperbolic functions

Following previous studies by Bagnold and Barndorff-Nielsen et al., the present work employs the log—hyperbolic function to fit experimentally measured particle size distributions originating from quite different experiments. It is shown that the log—hyperbolic function permits a satisfactory representation of all size distributions studied in this work. Hence, it appears that experimental particle size distributions are well described by the four characteristic parameters occurring in the log—hyperbolic function. These parameters can therefore be employed to study similarities or differences between particle size distributions and/or to describe temporal and spatial variations of distributions. The function was applied to the following particle size distributions:

1. 1.— Mass—size distribution of a sand sample
2. 2.— Size distribution of diamonds
3. 3.— Size distribution of river bed sediments
4. 4.— Size distribution of glacio-fluvial sediments
5. 5.— Measurements of aerosol distributions
6. 6.— Particle size distributions in sprays
7. 7.— Molecular weight distributions

A brief account of previous work is given and the major properties of the log—hyperbolic function are described. Experimental particle size distributions of sand, diamonds, river bed sediments, spray droplets, aerosols, and polymer molecules are fitted by the log—hyperbolic function and it is shown that it satisfactorily applies to all distributions.     

Oxidation studies of various petroleum cokes

In situ scanning transmission electron microscopy has been used to evaluate various coke samples ranging from very Isotropic to ultrapremium needle-like in terms of their oxidation characteristics. Three major modes of attack were identified:

• 1.a) low-temperature (375°C) shallow pitting, which predominated in isotropic materials
• 2.b) high-temperature (525°C) deep pitting, which appeared to be associated with highly anisotropic structures and
• 3.c) edge recession, which occurred with all cokes but was most apparent with anisotropic structures.

A rationale is presented which accounts for the behavior of isotropic and anisotropic cokes in oxygen     

Preparation of sulphide concentrates from petroleum distillates by extraction with organic solvents

• 1.1. A system was developed from a study of the selectivity of extraction agents and conditions selected for the isolation of sulphide concentrates from straight-run diesel fractions by two-stage sequential extraction with furfural and phenol.
• 2.2. From fractions of Arlan crude sulphide concentrates with an overall sulphur content of 8:9% and sulphide content of 7:8.3% were obtained. The method proposed for extraction enables 38–45% sulphides contained in the fraction to be isolated, which is comparable with results of single-stage sulphuric acid extraction.
• 3.3. A study was made of advantages of furfural-phenol extraction to sulphuric acid extraction and methods of further improvements as a result of the optimization of process parameters and the use of extraction reagents of increased selectivity.

     

Fresh water from the sea,a new process

• 1. 1. The process is designed to produce ice crystals uniform in shape and size, without the formation of other new nuclei.
• 2. 2. Nucleation and crystal growth are separate operations; the former is batch-wise; the latter is continuous.
• 3. 3. The predetermined number of nuclei charged to the crystal chamber is equal to the production per unit divided by crystal weight.
• 4. 4. The refrigerant is supplied along the flow path in the chamber at a rate equivalent to the crystal growth rate.
• 5. 5. Separation of the uniform crystals from the residual sea water is a true gravity operation - the less dense ice floating away from the more dense residual sea water.

     

Esters of α-branched acids (synthetic oils)

• 1.1. Esters of neopentylpolyols and α-branched monocarboxylic acids were synthesized and their physical and chemical and operational properties examined.
• 2.2. Synthetic esters with an increased content of quaternary carbon atoms were characterized by an increased temperature of solidification and improved lubricating properties.
• 3.3. With and increase of the number of α-branches in the structure of esters, oxidizing properties improve.

     

Chemical modification of polymers I. Applications and synthetic strategies

This paper does not claim to be an exhaustive review of chemical modification but rather aims to illustrate with some examples the vast possibilities offered by this method of synthesis. Grafting and crosslinking reactions as such, which lie outside the present concept of chemical modification (defined as the application of macromolecules in the traditional reactions of organic chemistry) as well as reactions in heterogeneous media do not form part of this review. Five aspects of main interest are:

• •—synthesis of copolymers not accessible by classical means,
• •—comparison of polymer modification and polymerization of functional monomers,
• •—aids to the analysis of polymer microstructures,
• •—introduction of reactive sites along a polymer chain,
• •—fixation of active molecules.

Chemical modification of polymers is generally undertaken to synthesize polymers for well defined applications as can be seen in the case of supported catalysts and reagents, phase transfer catalysts, supported syntheses, and pharmacological use. The synthetic strategies will be described in more detail in Part II (fixation of acids on a polymeric chain). Part III will emphasize the kinetic aspects of the chemical modification of polymers and Part IV will deal with complex reactions.     

Preparation of p-isopropylphenol by selective oxidation of p-di-isopropylbenzene

• 1.1. A method was developed for preparing p-isopropylphenol by oxidation of p-di-isopropylbenzene with a monohydroperoxide yield of 90%.
• 2.2. In acidic decomposition of monohydroperoxide of p-di-isoprophybenzene in the presence of cation exchange resins p-isopropylphenol yield was 98–99%. Kinetic studies of acidic decomposition of monohydroperoxide of p-di-isoprophylbezene show that the rate of acidic decompositon in the presence of catalysts containing a nitro-group is doubled.

     

Materials in brief

• Clariant Corporation
• Expancel Inc

     

Study of cycloparaffins by GC/MS

• 1.1. A GC/MS method was developed for the structural differentiation of cyclo-parffins, based on a dehydrogenation reaction in the GC/MS system (catalyst 20% Pt/C; reaction temperature 320°C; chromatographic separation in a mixture of 95% helium and 5% hydrogen).
• 2.2. Transformation of cycloparaffins into aromatic hydrocarbons during GC/MS analysis permits the presence and the number of cyclohexane rings in the molecule and the type of substituent to be evaluated.

     

In brief

Including brief stories on:

• Chinaplas 2003
• NPE 2003