Dissertations / Theses on the topic 'Saturated hydrocarbon'

Polyolefin blends represent a vital material field due to their economic and commercial importance. Potential new properties such as lighter weight, lower cost and higher strength, motivate research to investigate blends of saturated hydrocarbon polymers. However, many questions remain concerning how polymer chain structure and packing influence local thermodynamics, or more specifically, the interplay between enthalpy and entropy, which ultimately control bulk phase behavior. Solid-state NMR has proven to be an essential tool in these studies due to its ability to selectively observe molecular level conformations and dynamics without isotopic labeling. Combinations of basic and advanced variable temperature studies such as 1D and 2D 13C cross-polarization exchange experiments, static 2H lineshape analysis, 1H relaxation/spin-diffusion measurements, and 129Xe experiments were applied in this work. Several systems were studied, including 50/50 weight percent blends of polyisobutylene with polyethylene-co-1-butene, polyisobutylene with head-to-head polypropylene, and atactic polypropylene with the same polyethylene-co-1-butene samples. The results were used to determine a relationship between miscibility, length scales of mixing, and timescales/length scales of the glass transition.

A number of novel hydrocarbon cage systems have been designed and characterized using ab initio molecular orbital calculations at the MP2 and B3-LYP levels. In particular,equilibrium structures for five families of molecules, hemialkaplanes, hemispiroalkaplanes, alkaplanes, spiroalkaplanes and dimethanospiroalkaplanes, have been examined in detail with the aim of designing a saturated hydrocarbon with a planar-tetracoordinate carbon atom and with a view to identifying appropriate synthetic targets. ¶ The hemialkaplanes and hemispiroalkaplanes are constructed from a spiropentane or neopentane subunit, respectively, which is capped by a cyclic hydrocarbon. The hemispiroalkaplanes are predicted to contain a pyramidal-tetracoordinate carbon atom possessing a lone pair of electrons. Protonation at this apical carbon atom is found to be highly favorable, resulting in a remarkably high basicity for a saturated hydrocarbon. The proton affinities of the hemispiroalkaplanes are calculated to be more than 1170 kJ mol[superscript -1] , even greater than those for the diamine "proton sponges". ¶ The alkaplanes and the spiroalkaplanes, which are constructed by bicapping a neopentane or spiropentane subunit, respectively, with a pair of cyclic hydrocarbons, show unprecedented flattening of a tetracoordinate carbon atom. Linking the spiroalkaplane caps with methano bridges gives the dimethanospiroalkaplanes, two of which, dimethanospirooctaplane and dimethanospirobinonaplane, achieve exact planarity at the central carbon atom. They are the first neutral saturated hydrocarbons predicted to contain an exactly planartetracoordinate carbon atom. This has been achieved through structural constraints alone. The electronic structure at the central carbon atom results in a highest occupied molecular orbital corresponding to a p-type lone pair. Consequently, the adiabatic ionization energies for octaplane, spirooctaplane and dimethanospirooctaplane (approximately 5 eV) are predicted to be similar to those of lithium and sodium - incredibly low for a saturated hydrocarbon. ¶ Some consideration has been given to likely pathways for unimolecular decomposition for all species. Predicted structures, heats of formation and strain energies for all the novel hydrocarbons are also detailed. Tetramethylhemispirooctaplane and dimethanospirobinonaplane are identified as the preferred synthetic targets.

Dans les coupes pétrolières ou gazoles, le dépôt solide cristallise lors de baisses sensibles de la température est constitué en partie de solutions solides de n-alcanes. Compte tenu de la complexité de ces mélanges, la connaissance de leur comportement est nécessaire pour une analyse thermodynamique permettant d'approcher une modélisation du point de trouble des coupes pétrolières paraffiniques ou gazoles. Dans ce travail nous avons détermine les diagrammes de phases des deux systèmes binaires (nc₂₃: nc₂₄ nc₂₃: nc₂₂par l'utilisation conjointe de l'analyse thermique différentielle, de l'analyse enthalpimétrique, de l'analyse thermomécanique et de la diffraction des rayons X. Ceci nous a permis de mettre en évidence plusieurs phases intermédiaires et une systématique dans le comportement de n-alcanes pour les systèmes binaires pairs-impairs. L'étude thermodynamique comporte le représentation des mesures de la variation d'enthalpie en fonction de la température par un modèle du solide d'Einstein, les expressions analytiques des fonctions thermodynamiques sont exploitées pour le calcul des diagrammes de phases en représentant les grandeurs d'excès pour un modèle de margules à deux paramètres

ABSTRACT FUNCTIONALIZATION OF SATURATED HYDROCARBONS: HIGH TEMPERATURE BROMINATION Gü
nbaS, Duygu Deniz M.S., Department of Chemistry Supervisor: Prof. Dr. Metin Balci June 2006, 174 pages Although saturated hydrocarbons are readily available and extremely cheap starting materials, they can not be used in synthetic chemistry without prior activation. Efficient functionalization of alkanes leading to the production of useful organic chemicals in an industrial scale is of considerable interest for the chemical and pharmaceutical industries and remains a long-term challenge for chemists. In this respect, halogenations of hydrocarbons which leads to a variety of useful synthetic intermediates is an open avenue which deserves special attention. It is also noteworthy to mention that efficient methods for selective functionalization of saturated bicyclic hydrocarbons still remains elusive, albeit a number of methods employing various reagents have been developed for the C&
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H bond activation of open chain and monocyclic alkanes. Herein, we will investigate the high temperature bromination reactions as a method for functionalization of saturated bicyclic hydrocarbons such as octahydropentalene (1), octahydro-1H-indene (2) and 1a,2,7,7a-tetrahydro-1H-cyclopropa[b]naphthalene (3). The scope and the limitations of the reaction will reveal the regio-and stereoselectivity. Furthermore, formation mechanism of the products will be discussed and the chemistry of these compounds will be extended for further functionalization

ABSTRACT FUNCTIONALIZATION OF SATURATED BICYCLIC HYDROCARBONS: HIGH TEMPERATURE BROMINATION Ö
zer, Melek Sermin M.Sc., Department of Chemistry Supervisor: Prof. Dr. Metin Balci January 2011, 139 pages Although hydrocarbons are readily available and extremely cheap starting materials, they cannot be used in synthetic chemistry without prior activation. The selective functionalization of saturated hydrocarbons under mild conditions is of both biochemical and industrial importance. Initially, saturated hydrocarbons such as octahydro-1H-indene 80, octahydro-1H-4,7-methanoindene 81 and bicyclo[4.2.0]octan-7-one 82 were synthesized as starting materials. Then high temperature bromination reactions of these saturated hydrocarbons as a method for C-H bond activation have been investigated and the synthetic application of the formed intermediates has been searched. Furthermore, the role of the alkyl substituents in tricyclic systems and the effect of carbonyl group in bicyclo[4.2.0] octan-7-one 82 have been studied and the mechanism for the formation of the products have been discussed. Finally, whole products were conscientiously purified and characterized.

Dans le cadre d'un contrat européen sur la modélisation du transport des polluants à travers des sols contaminés, des expériences en colonne de laboratoire ont été réalisées afin de déterminer les propriétés de rétention de deux hydrocarbures polyaromatiques (naphtalène et phénanthrène) à travers des sables de contenu en matière organique variable en nature et en quantité. Il a ainsi été confirmé que la matière organique jouait un rôle prépondérant dans le processus de rétention. Il a été montré que le polluant le plus hydrophobe (phénanthrène) s'adsorbait également sur la partie minérale des sables même si cette interaction linéaire, est de faible intensité comparée à celle obtenue sur les sables organiques. Le naphtalène nous a permis de montrer que le type et l'intensité de la rétention d'un polluant hydrophobe dépendaient de la nature de la matière organique. L’étude menée jusqu'au voisinage de la solubilité a mis en évidence d'importants effets non-linéaire. La modélisation a montré la nécessité de prendre à la fois en compte la non-linéarité des isothermes et la cinétique de transfert de matière entre phase. La confrontation modèle/expérience a conduit à l'estimation des temps caractéristiques de transfert par diffusion au sein des agrégats poreux. Le rôle joué par la matière organique sur la rétention d'un tensioactif anionique pur (le n-paraoctylbenzène sulfonate de sodium) a été mis en évidence et quantifié. Un modèle de transport couplant les mécanismes d'échange cationique, de micellisation, de précipitation et d'adsorption a été proposé.

This thesis reports the results of investigations carried out into the composition of the saturate and aromatic unresolved complex mixtures (UCMs) in crude oils. It is divided into two sections. Section A reports on studies of the saturate UCM and Section B reports on studies of the aromatic UCM. UCMs are mixtures of very large numbers of compounds of low individual abundances, hence structural information on individual components is difficult or impossible to obtain using conventional GC or GC-MS techniques. The investigations reported in this thesis used a combination of GC-MS techniques (Section A) and oxidations of UCMs followed by GC-MS characterisation of the oxidation products (Section B) to develop a more detailed picture of the structures of components of the saturate and aromatic UCMs. UCMs are present in all crude oils, and may account for the vast majority of the material present in heavily weathered or biodegraded oils. An understanding of the types of compounds present may have a bearing on the refining processes an oil is subjected to, as well as assessing its potential environmental and toxicological effects.Single branched C(subscript)18 isomers were prepared to establish the chromatographic behaviour and mass spectral fragmentation patterns of open chain compounds with ethyl-, propyl-, butyl- and pentyl- substituents. All open chain structural isomers with a single n-alkyl branch larger than methyl in the range C(subscript)10 to C(subscript)20 were identified at each carbon number in a series of crude oils of varying ages, source types and depositional environments. Also, C(subscript)21 to C(subscript)25 structural isomers containing an ethyl branch were identified in all of these samples. This represents a total of 163 compounds. These monoalkylalkanes comprise approximately 3 % of the alkanes in these oils, with the n-alkanes (35-60 %) and methylalkanes (10 %) being the most abundant compound classes present. Isoprenoids, alkylcyclohexanes and other branched and/or cyclic alkanes make up the remainder of the material.Rock samples from a sedimentary sequence of Late Cretaceous age were analysed for ethylalkanes using GC-MS techniques. In the less mature samples, 3- and 5-ethylalkanes were in higher abundance relative to the other isomers at odd carbon numbers from C(subscript)17 to C(subscript)23. In the more mature samples, this odd preference was no longer apparent. Several other low maturity sediment samples were analysed and found to have a similar ethylalkane distribution to the shallow sample from the sedimentary sequence. A mature crude oil which was also analysed exhibited a distribution similar to the deeper sample from the sedimentary sequence. Tetralin pyrolysis of a low maturity lignite sample yielded only the 3- and 5-substituted ethylalkanes, providing supporting evidence that the initial odd preference is the result of defunctionalisation of specific natural product precursors containing a 3- or 5-ethylalkyl structural moiety. With increasing maturity this preference is diluted by input of ethylalkanes without preference. A mechanism involving acid-catalysed rearrangement of n-alkenes to form monoalkylalkanes is proposed to account for the loss of preference in ethylalkane relative abundances.Investigations into the composition of aromatic unresolved complex mixtures were conducted by oxidising the total aromatic fraction of a moderately biodegraded crude oil (biodegradation level 4) using potassium permanganate. This reagent cleaves the alkyl substituents attached to aromatic rings between the alpha and beta carbons and oxidises the alpha carbon to a carboxylate group. A biodegraded crude oil was chosen because the majority of the resolved components have been removed by biodegradation, leaving a complex mixture of compounds almost completely unresolved by gas chromatography. The oxidation product was separated into dichloromethane-soluble monocarboxylic acids (both aliphatic and aromatic) and water-soluble polycarboxylic acids (aromatic only). GC-MS analysis of these oxidation products gave the proportions of monosubstituted:disubstituted:trisubstituted:tetrasubstituted monoaromatic rings as 29:59:12:0.1, of which from one to three substituents were carboxylic acid groups with the remainder of the substituents being unoxidised methyl groups. Of the disubstituted monoaromatic oxidation products, 53 % were dicarboxylic acids with the most sterically hindered 1,2-substitution pattern. This observation was interpreted as evidence for the presence of significant amounts of naphthenoaromatic systems such as tetralins and indanes in the crude oil aromatic fraction. Analysis of the permanganate oxidation products also enabled a quantitative measure of the proportion of methyl substituents to be made. It was found that methyl groups accounted for a significant proportion of the alkyl substituents attached to aromatic systems. Of the disubstituted monoaromatic oxidation products, 59 % had a methyl group as one of the substituents, while of trisubstituted monoaromatic systems, 41% had one methyl and 37 % had two methyls. Compounds containing a biphenyl carbon skeleton comprised 3 % of the aromatic oxidation products, with isomers containing from one to four substituents of which one was a carboxylic acid group and the remainder were unoxidised methyls. This indicates that biphenyls containing more than one alkyl (>C(subscript)1) substituent were not present. Of the monosubstituted biphenylcarboxylic acids, the ratio of ortho:meta:para substituted isomers was 0:65:35, which correlates well with literature reports of the relative abundances of methylbiphenyl isomers, and suggests that the overall distribution of all monosubstituted biphenyls has not been significantly affected by biodegradation to level 4.The monoaromatic, diaromatic and triaromatic fractions of the same biodegraded crude oil (level 4) were separately treated with ruthenium tetroxide, which cleaves aromatic rings so that the ring carbon bearing the substituent is oxidised to become the carbonyl carbon of a carboxylic acid. These oxidation products represent the alkyl moieties that were attached to aromatic rings in the initial crude oil aromatic fractions. Identification of these alkyl side chains provides an insight into the nature of the components of the aromatic crude oil UCM. The oxidation products were separated into dichloromethane-soluble monocarboxylic acids, which were subsequently reduced to monodeuterated hydrocarbons for characterisation using gas chromatography-mass spectrometry (GC-MS) techniques, and water-soluble dicarboxylic acids which were analysed as dimethyl esters. n-Alkanes, methylalkanes, alkylalkanes, alkylcyclohexands, methylalkylcyclohexanes, isoprenoids and bicyclic alkanes were identified in the monodeuterated hydrocarbon samples derived from all three aromatic fractions. Most of these compounds had carbon skeletons strikingly similar to those observed in the saturate fractions of unbiodegraded crude oils, with the only differences being the addition of a carbon from the aromatic ring, and the presence of a deuterium atom attached to that carbon. Because the electron-withdrawing nature of carboxylic acid groups prevents further aromatic ring oxidation, numerous aromatic monocarboxylic acids were also identified in the acidic products of the oxidation of the crude oil diaromatic and triaromatic fractions. These included C(subscript)1 to C(subscript)3 alkyl-substituted benzoic acids derived from compounds containing a biphenyl or phenylnaphthalene structural moiety, as well as omega-phenylalkanoic acids with chain lengths up to C(subscript)11, derived from compounds in which two aromatic systems are connected by an alkyl chain. The main components of the dicarboxylic acid oxidation products of all three aromatic fractions were alpha, omega-dicarboxylic acids and alkylcyclopentane-dicarboxylic acids and alkylcyclohexane-dicarboxylic acids, with phthalic acids also present in the oxidation products of the diaromatic and triaromatic fractions. The observation that 1,5-pentanedicarboxylic acids and 1,6-hexanedicarboxylic acids were the only alpha, omega-dicarboxylic acids in the oxidation products of the crude oil monoaromatic fraction, and were present in high abundance relative to other alpha, omega-dicarboxylic acids in the oxidation products of the diaromatic and triaromatic fractions indicated that substituted indanes and/or tetralins were quantitatively important constituents of the overall crude oil aromatic fraction. This finding is supported by the results of the analysis of the mass spectra of the crude oil aromatic fractions.These studies of aromatic UCMs have provided new insights into the origins of the aromatic components of petroleum. The presence of a pronounced odd-over-even predominance in the C(subscript)25, C(subscript)27, and C(subscript)29 monodeuterated n-alkanes (CPI = 1.07), which corresponds to the odd-over-even predominance observed in the n-alkane components of unbiodegraded crude oils from the same basin, suggests that the n-alkyl side chains and the n-alkanes have a common source. Evidence is presented to support the hypothesis that the n-alkylaromatics are formed in part by geosynthetic processes involving alkylation of aromatic systems by electrophilic species such as carbocations and acylium ions formed from carboxylic acids. This hypothesis is then extended to explain the formation of other groups of compounds, including aromatic systems with isoprenoidal-, methylalkyl- and monoalkyl-branched side chains. Because isoprenoids, methylalkanes and alkylalkanes are well-known components of petroleum, these results suggest that these alkylaromatic components of petroleum may share a common source with the corresponding alkane components. It is suggested that aromatic unresolved complex mixtures arise due to the very large number of structurally related compounds present, which are formed by geosynthetic processes such as alkylation of aromatic rings.

This thesis reports the results of investigations carried out into the composition of the saturate and aromatic unresolved complex mixtures (UCMs) in crude oils. It is divided into two sections. Section A reports on studies of the saturate UCM and Section B reports on studies of the aromatic UCM. UCMs are mixtures of very large numbers of compounds of low individual abundances, hence structural information on individual components is difficult or impossible to obtain using conventional GC or GC-MS techniques. The investigations reported in this thesis used a combination of GC-MS techniques (Section A) and oxidations of UCMs followed by GC-MS characterisation of the oxidation products (Section B) to develop a more detailed picture of the structures of components of the saturate and aromatic UCMs. UCMs are present in all crude oils, and may account for the vast majority of the material present in heavily weathered or biodegraded oils. An understanding of the types of compounds present may have a bearing on the refining processes an oil is subjected to, as well as assessing its potential environmental and toxicological effects.Single branched C(subscript)18 isomers were prepared to establish the chromatographic behaviour and mass spectral fragmentation patterns of open chain compounds with ethyl-, propyl-, butyl- and pentyl- substituents. All open chain structural isomers with a single n-alkyl branch larger than methyl in the range C(subscript)10 to C(subscript)20 were identified at each carbon number in a series of crude oils of varying ages, source types and depositional environments. Also, C(subscript)21 to C(subscript)25 structural isomers containing an ethyl branch were identified in all of these samples. This represents a total of 163 compounds. These monoalkylalkanes comprise approximately 3 % of the alkanes in these oils, with the n-alkanes (35-60 %) and ++
methylalkanes (10 %) being the most abundant compound classes present. Isoprenoids, alkylcyclohexanes and other branched and/or cyclic alkanes make up the remainder of the material.Rock samples from a sedimentary sequence of Late Cretaceous age were analysed for ethylalkanes using GC-MS techniques. In the less mature samples, 3- and 5-ethylalkanes were in higher abundance relative to the other isomers at odd carbon numbers from C(subscript)17 to C(subscript)23. In the more mature samples, this odd preference was no longer apparent. Several other low maturity sediment samples were analysed and found to have a similar ethylalkane distribution to the shallow sample from the sedimentary sequence. A mature crude oil which was also analysed exhibited a distribution similar to the deeper sample from the sedimentary sequence. Tetralin pyrolysis of a low maturity lignite sample yielded only the 3- and 5-substituted ethylalkanes, providing supporting evidence that the initial odd preference is the result of defunctionalisation of specific natural product precursors containing a 3- or 5-ethylalkyl structural moiety. With increasing maturity this preference is diluted by input of ethylalkanes without preference. A mechanism involving acid-catalysed rearrangement of n-alkenes to form monoalkylalkanes is proposed to account for the loss of preference in ethylalkane relative abundances.Investigations into the composition of aromatic unresolved complex mixtures were conducted by oxidising the total aromatic fraction of a moderately biodegraded crude oil (biodegradation level 4) using potassium permanganate. This reagent cleaves the alkyl substituents attached to aromatic rings between the alpha and beta carbons and oxidises the alpha carbon to a carboxylate group. A biodegraded crude oil was chosen because the majority of the resolved components have been removed by biodegradation, ++
leaving a complex mixture of compounds almost completely unresolved by gas chromatography. The oxidation product was separated into dichloromethane-soluble monocarboxylic acids (both aliphatic and aromatic) and water-soluble polycarboxylic acids (aromatic only). GC-MS analysis of these oxidation products gave the proportions of monosubstituted:disubstituted:trisubstituted:tetrasubstituted monoaromatic rings as 29:59:12:0.1, of which from one to three substituents were carboxylic acid groups with the remainder of the substituents being unoxidised methyl groups. Of the disubstituted monoaromatic oxidation products, 53 % were dicarboxylic acids with the most sterically hindered 1,2-substitution pattern. This observation was interpreted as evidence for the presence of significant amounts of naphthenoaromatic systems such as tetralins and indanes in the crude oil aromatic fraction. Analysis of the permanganate oxidation products also enabled a quantitative measure of the proportion of methyl substituents to be made. It was found that methyl groups accounted for a significant proportion of the alkyl substituents attached to aromatic systems. Of the disubstituted monoaromatic oxidation products, 59 % had a methyl group as one of the substituents, while of trisubstituted monoaromatic systems, 41% had one methyl and 37 % had two methyls. Compounds containing a biphenyl carbon skeleton comprised 3 % of the aromatic oxidation products, with isomers containing from one to four substituents of which one was a carboxylic acid group and the remainder were unoxidised methyls. This indicates that biphenyls containing more than one alkyl (>C(subscript)1) substituent were not present. Of the monosubstituted biphenylcarboxylic acids, the ratio of ortho:meta:para substituted isomers was 0:65:35, which correlates well with literature reports of the relative abundances of methylbiphenyl ++
isomers, and suggests that the overall distribution of all monosubstituted biphenyls has not been significantly affected by biodegradation to level 4.The monoaromatic, diaromatic and triaromatic fractions of the same biodegraded crude oil (level 4) were separately treated with ruthenium tetroxide, which cleaves aromatic rings so that the ring carbon bearing the substituent is oxidised to become the carbonyl carbon of a carboxylic acid. These oxidation products represent the alkyl moieties that were attached to aromatic rings in the initial crude oil aromatic fractions. Identification of these alkyl side chains provides an insight into the nature of the components of the aromatic crude oil UCM. The oxidation products were separated into dichloromethane-soluble monocarboxylic acids, which were subsequently reduced to monodeuterated hydrocarbons for characterisation using gas chromatography-mass spectrometry (GC-MS) techniques, and water-soluble dicarboxylic acids which were analysed as dimethyl esters. n-Alkanes, methylalkanes, alkylalkanes, alkylcyclohexands, methylalkylcyclohexanes, isoprenoids and bicyclic alkanes were identified in the monodeuterated hydrocarbon samples derived from all three aromatic fractions. Most of these compounds had carbon skeletons strikingly similar to those observed in the saturate fractions of unbiodegraded crude oils, with the only differences being the addition of a carbon from the aromatic ring, and the presence of a deuterium atom attached to that carbon. Because the electron-withdrawing nature of carboxylic acid groups prevents further aromatic ring oxidation, numerous aromatic monocarboxylic acids were also identified in the acidic products of the oxidation of the crude oil diaromatic and triaromatic fractions. These included C(subscript)1 to C(subscript)3 alkyl-substituted benzoic acids derived from compounds containing a biphenyl ++
or phenylnaphthalene structural moiety, as well as omega-phenylalkanoic acids with chain lengths up to C(subscript)11, derived from compounds in which two aromatic systems are connected by an alkyl chain. The main components of the dicarboxylic acid oxidation products of all three aromatic fractions were alpha, omega-dicarboxylic acids and alkylcyclopentane-dicarboxylic acids and alkylcyclohexane-dicarboxylic acids, with phthalic acids also present in the oxidation products of the diaromatic and triaromatic fractions. The observation that 1,5-pentanedicarboxylic acids and 1,6-hexanedicarboxylic acids were the only alpha, omega-dicarboxylic acids in the oxidation products of the crude oil monoaromatic fraction, and were present in high abundance relative to other alpha, omega-dicarboxylic acids in the oxidation products of the diaromatic and triaromatic fractions indicated that substituted indanes and/or tetralins were quantitatively important constituents of the overall crude oil aromatic fraction. This finding is supported by the results of the analysis of the mass spectra of the crude oil aromatic fractions.These studies of aromatic UCMs have provided new insights into the origins of the aromatic components of petroleum. The presence of a pronounced odd-over-even predominance in the C(subscript)25, C(subscript)27, and C(subscript)29 monodeuterated n-alkanes (CPI = 1.07), which corresponds to the odd-over-even predominance observed in the n-alkane components of unbiodegraded crude oils from the same basin, suggests that the n-alkyl side chains and the n-alkanes have a common source. Evidence is presented to support the hypothesis that the n-alkylaromatics are formed in part by geosynthetic processes involving alkylation of aromatic systems by electrophilic species such as carbocations and acylium ions formed from carboxylic acids. This hypothesis is then extended to ++
explain the formation of other groups of compounds, including aromatic systems with isoprenoidal-, methylalkyl- and monoalkyl-branched side chains. Because isoprenoids, methylalkanes and alkylalkanes are well-known components of petroleum, these results suggest that these alkylaromatic components of petroleum may share a common source with the corresponding alkane components. It is suggested that aromatic unresolved complex mixtures arise due to the very large number of structurally related compounds present, which are formed by geosynthetic processes such as alkylation of aromatic rings.

Mestrado em Engenharia Alimentar - Instituto Superior de Agronomia
Mineral oil is a by-product derived from petroleum distillation, applicable in the areas of cosmetics, pharmaceuticals and food, used as food additive when in the proper grade of purity for this propose. However, it can also be considered a contaminant, especially important in sunflower oil, due to the episode of the 100.000 tons of highly contaminated Ukrainian sunflower oil. This experimental work aims at implementing a method for the determination of saturated aliphatic hydrocarbons in sunflower oil by capillary gas chromatography with on column injection and FID detector. For such purpose parameters like linearity, working range, thresholds, precision, accuracy and robustness of the method were evaluated. The results show that the method is linear in the range between 15 and 60 mg.kg-1, with a repeatability limit of 6,11 mg.kg-1 and a variability of results obtained by this method of 0,48 mg.kg-1. The method allows to detect and quantify the analyte from 21 mg.kg-1 and 24 mg.kg-1, respectively. Considering the results obtained in recovery tests and Z-score of 0,5 and 0,04 obtained in inter-laboratory tests, the method is accurate. The robustness of this method is also verified, although it is sensible to the way the integration is performed

Crude oil leakages often give rise to in situ contamination with both oil and salt. In this study, the biodegradation of model alkanes and of saturated hydrocarbons in whole crude oil by hydrocarbon-degrading bacteria was investigated at different salt (NaCl, KCl, Na2SO4) concentrations. Changes in cell surface hydrophobicity at different NaCl concentrations were also investigated. The results show that with increasing NaCl concentration, the lag phase for strain growth on hydrocarbons was prolonged; however, the total degradation efficiency was not influenced greatly. The formation of different sizes of cell aggregates at different salt concentrations indicated that salt could indirectly influence mass transfer of hydrocarbons from the medium to the interior of the cells. The results also showed that KCl had a less inhibitory effect on biodegradation than NaCl, and changes of Na2SO4 concentration did not greatly affect biodegradation. In addition, cell surface hydrophobicity increased with increasing NaCl concentration when the cultures were grown on hydrocarbons.

L'etude experimentale de l'oxydation du butane et du butene-1 a ete effectuee en reacteur auto-agite par jets gazeux dans un large domaine de conditions experimentales (900-1200 k, 1 a 10 atm, rapports d'equivalents oxygene-hydrocarbure 0,1-4)

Utilisation du formalisme des fonctions adaptées à la symétrie pour développera les différentes densités de probabilité intéressant les cristaux à désordre d'orientation. Obtention des sections efficaces de diffusion neutronique en fonction d'un petit nombre de coefficients independants, reflétant les propriétés de symétrie du cristal et de la molécule. Application à l'analyse des facteurs de structure de diffraction de monocristaux de néopentane et de perchlorate de potassium.

The increased use of alcohols as gasoline additives, and possible substitutes, has prompted the investigation of the fate of gasoline/alcohol mixtures in the environment. In situ bioremediation is one technique that can successfully be applied to remove ground water contaminants particularly in situations where the adsorptive capacity of the soil plays a major role. Frequently, enhanced in situ bioremediation techniques rely on indigenous microorganisms to degrade ground water contaminants; this technique may sometimes include the addition of acclimated bacteria.

In this study, soil microcosms were constructed in order to simulate the conditions found in a saturated aerobic aquifer. The biodegradation potential of methanol, benzene, and m-xylene was investigated. Uncontaminated soil from the surface, 12, 16.5, and 18 foot depths was utilized to observe the differences in microbial responses throughout the soil profile. The biodegradation potential of the indigenous microbiota was determined and compared to that of benzene acclimated bacteria, for all the compounds in the mixture. To observe the impact that chemical and physical soil characteristics may have on microbial responses, soils from each depth were classified on the basis of their particle size, moisture content and pH.

Substantial methanol, benzene, and m-xylene biodegradation by the indigenous microorganisms occurred in all subsurface soils. While methanol was readily biodegradable over concentrations ranging from about 80 mg/L to about 200 mg/L, benzene inhibited methanol biodegradation at about 125 mg/L in all soil depths. The addition of benzene acclimated bacteria considerably increased the biodegradation rates of all compounds in the mixture. Such increases in biodegradation rates may be attributed to the activities of both groups, the indigenous microorganisms and the benzene acclimated bacteria. The results obtained by this study suggest that biodegradation of methanol, benzene, and m-xylene can readily occur in a saturated aerobic subsurface environment. The physical and chemical properties of a ground water aquifer seem to have a marked effect on microbial responses, and consequently on the biodegradation potential of water contaminants.

Master of Science

Sous pression elevee d'hydrogene (>10 bar) les catalyseurs platine mordenite sont tres selectifs pour l'isomerisation de l'hexane et presentent une tres grande stabilite. Un maximum d'activite est observe pour une valeur du rapport si/al de la charpente zeolithique voisine de 10. Un modele cinetique a ete propose pour rendre compte de l'effet des parametres operatoires sur la vitesse d'isomerisation

Etude theorique des phases plastiques des cristaux moleculaires. La premiere partie se propose d'expliquer le profil spectral raman de certains modes de vibrations internes en utilisant la technique des fonctions rotateurs symetriques pour exprimer d'une facon generale, l'interaction vibrationnelle entre modes appartenant a diverses molecules. Les resultats sont ensuite appliques aux modes internes detectables par diffusion raman et qui sont, simultanement, fortement actifs en absorption ir. La seconde partie contient une simulation par dynamique moleculaire d'un modele realiste d'un cristal de neopentane dans sa phase plastique

On compare le comportement de differents oxydes non reductibles en isosynthese. Cette reaction conduit a partir de co+h::(2) ou de ch::(3)oh+h::(2) a la formation d'hydrocarbures ramifies (isobutane), d'aromatiques ainsi que de composes oxygenes (methanol, isobutanol). Les produits formes presentent une distibution originale qui s'ecarte d'une repartition de schulz-flory. Les schemas reactionnels proposes pour la formation des iso c::(4) sont la voie acetate, la condensation aldolique et l'hydrogenation d'especes chimisorbees de co du type (co)::(n). La formation des aromatiques est susceptible d'emprunter cette derniere voie a partir des rhodizonates (co)::(6) fixes a la surface des catalyseurs

La composition de la couche adsorbee a l'interface de systemes diphasiques : eau+nacl; dodecane, dodecylsulfate de sodium ou dodecylbenzenesulfonate comme agent de surface et butanol, pentanol ou alcool benzylique comme coagent de surface, est determinee par application de la loi de gibbs

L'oxydation de l'éthylène, du propane et du propène a été étudiée dans un large domaine de température (900 à 1200 Kelvin), de pression (0,1 à 1 MPa) et de richesse (0,15 à 4) au moyen d'un réacteur auto-agité par jets gazeux. L'analyse chromatographique d'échantillons du milieu réactionnel permet de suivre la réaction d'oxydation dans son ensemble. Un mécanisme cinétique détaillé comportant 278 réactions et faisant intervenir 47 espèces chimiques, a été développé grâce à l'utilisation d'une technique d'analyse de sensibilité, et permet de modéliser correctement nos résultats expérimentaux.

Etude de l'interaction entre les terres rares et les metaux de transition en jouant sur le mode d'impregnation, la nature des sels precurseurs des metaux de transition et des lanthanides et traitement thermique d'activation. Etude sur la dispersion et sur l'etat d'oxydation

Using a combination of micromechanical force and flowloop measurements, hydrate deposition on a pipe wall surface was investigated for ‘dry’ hydrates formed in the bulk phase and for hydrates growing on the pipe surface. Cyclopentane ‘dry’ hydrates (without a free water phase) were used to predict whether hydrates, formed in a bulk condensate phase, would adhere to a pipe wall. Adhesion forces between cyclopentane hydrates and steel were measured using a micro-mechanical force apparatus. The average force of adhesion was measured to be very small, less than 0.01 N/m. This force was used in a particle force balance, predicting that hydrates formed in the bulk phase would not deposit on the pipe wall. It was hypothesized than in the presence of a water saturated hydrocarbon, hydrates would grow on the pipe wall as the fluid cooled below its equilibrium temperature. This hypothesis was confirmed using a single pass condensate flowloop. Water was continuously dissolved into the flowloop inlet stream as water deposited in the flowloop test section, resulting in both a pressure drop and fluid temperature increase. This work illustrates the need for a hydrate wall growth model.

A number of novel hydrocarbon cage systems have been designed and characterized using ab initio molecular orbital calculations at the MP2 and B3-LYP levels. In particular,equilibrium structures for five families of molecules, hemialkaplanes, hemispiroalkaplanes, alkaplanes, spiroalkaplanes and dimethanospiroalkaplanes, have been examined in detail with the aim of designing a saturated hydrocarbon with a planar-tetracoordinate carbon atom and with a view to identifying appropriate synthetic targets. ¶ ... ¶ Some consideration has been given to likely pathways for unimolecular decomposition for all species. Predicted structures, heats of formation and strain energies for all the novel hydrocarbons are also detailed. Tetramethylhemispirooctaplane and dimethanospirobinonaplane are identified as the preferred synthetic targets.

The work described herein is related to gas-phase ion-molecule reactions studied by using mass spectrometry. Chapter 2 describes density functional theory, a method used in chapters 4 and 5 to propose reaction mechanisms for reactions previously observed by others by using mass spectrometry. Chapter 3 describes a study that demonstrates that the fragmentation of saturated hydrocarbons occurs due to proton-transfer reactions that occur between these species and protonated molecules generated from molecules present in air such as nitrogen and water. Saturated hydrocarbons are studied in a wide variety of fields, and better methods to analyze complex mixtures of these compounds would facilitate their analysis. Chapter 4 discusses mechanisms of reactions for previously studied ion-molecule reactions of pyridynes studied by others by using mass spectrometry. Reactions of pyridynes are important to study arynes have been previously used in organic synthesis, and pyridine moieties are particularly common in biological compounds. Chapter 5 discusses density functional theory calculations used to determine why some organic polyradical undergo hydride abstractions from cyclohexane while others do not. The study discusses reactions taking place between both singlet and triplets states of the 2,5-didehydropyridinium cation and cyclohexane as a model, which are compared to reactions of the 2-pyridyl cation and 2-dehydropyridinium cation with cyclohexane. These studies may help improve our understanding of the reactivity-controlling factors of organic polyradicals, which may help improve toxic drug candidates like cytostatic enediynes.

Submitted in fulfillment of the requirements for the Master's of Technology: Chemistry, M L Sultan Technikon, 1999.
Saturated long chain hydrocarbons, such as paraffin waxes, have a large variety of applications. These applications may, however, be restricted by certain properties of the wax such as brittleness and in compounding. Cross-linking of the long chains in waxes may provide improved physical properties and hence a wider application of these waxes
M

碩士
國立臺北科技大學
環境規劃與管理研究所
95
This research is to use Hexane gas for reduction of nitrogen oxide by zero-valent iron fluidized bed reactor. Five different parameters: temperature (623, 673, 723 and 773K), Hexane concentrations (0, 1000, 1500 and 2000ppm), ZVI dosages (0.5, 1.0 and 2.0g), flux (0.4, 0.6 and 0.8 L/cm2-min), and O2 concentrations (3, 5 and 7%) were tested in the fluidized bed reactor to study 400ppm of NO. Under the ZVI dosages of 2.0g at flux 0.6 L/cm2-min at the temperature 773K, when the Hexane concentration is increased to 1000ppm from 0, the capacity of ZVI for De-NO decreases to 25.49 from 39.42 mg-NO/g-Fe. The capacity of ZVI for De-NO is the same when Hexane concentration is 1000 ,1500 or 2000ppm. When temperature is increased from 623K to 773K with 1500ppm Hexane, the capacity of ZVI for De-NO increased to 26.04 from 2.01 mg-NO/g-Fe. As the results, the increase of temperature can make the capacity of ZVI for De-NO to increase, but the increase of Hexane concentration will not affect the capacity. The capacity of ZVI for De-NO and breakthrough time can be affected by both ZVI dosage and flux variation. A parameter ZVI weight/flux (WFe/F) was developed to assess the breakthrough time of NO removed by ZVI and higher breakthrough time can be measured from higher WFe/F value. XRD and GC/MS were conducted to analyze the crystal structure and reacted gas. Several elements were determined from the spectrum：Hexane, Fe0(ZVI), Fe2C, FeCO3, Fe2O3, and Fe3O4. There are three chemical mechanisms among ZVI, nitric oxide, and Hexane, (1) 3Fe＋4NO→ Fe3O4＋2N2 (2)4Fe3O4＋2NO→ 6Fe2O3＋N2 (3)3Fe3O4＋C6H14→4Fe2C＋FeCO3＋7H2O＋CO2. Last, compared with removal efficiency of CO/ZVI/NO and Hexane/ZVI/NO, we found that the ecffectiveness of removal efficiency of CO was better.

Crude oil is a mixture of hydrocarbons so complex that it is predicted to comprise as many compounds as there are genes in the human genome. Developing methods to not only recover crude oil from the ground but also to convert crude oil into desirable products is challenging due to its complex nature. Thus, the petroleum industry relies heavily on analytical techniques to characterize the oil in reservoirs prior to enhanced oil recovery efforts and to evaluate the chemical compositions of their crude oil based products. Mass spectrometry (MS) is the only analytical technique that has the potential to provide elemental composition as well as structural information for the individual compounds that comprise petroleum samples. The continuous development of ionization techniques and mass analyzers, and other instrumentation advances, have primed mass spectrometry as the go-to analytical technique for providing solutions to problems faced by the petroleum industry. The research discussed in this dissertation can be divided into three parts: developing novel mass spectrometry-based methods to characterize mixtures of saturated hydrocarbons in petroleum products (Chapters 3 and 5), exploring the cause of fragmentation of saturated hydrocarbons upon atmospheric pressure chemical ionization to improve the analysis of samples containing these compounds (Chapter 4), and developing a better understanding of the chemical composition of crude oil that tightly binds to reservoir surfaces to improve chemically enhanced oil recovery (Chapter 6).