Alkylaromatic Hydrocarbons Research Articles

Production of higher alkylaromatic hydrocarbons from ethylene and toluene or o-xylene in the presence of bifunctional complex catalysts

Production of higher alkylaromatic hydrocarbons from ethylene and toluene or o-xylene in the presence of bifunctional complex catalysts

Relationship between rank and distribution of methylaromatic hydrocarbons for condensates of different origins

Aromatic hydrocarbon fractions from thirty gas condensates have been analysed by capillary GC and high resolution Shpol'skii spectroscopy for the determination of the relative distribution in methylphenanthrene (MP), dimethylphenanthrene (DMP) and methylpyrene (MPy) series. The measured maturity indices, MPI, DMPI and MPyI which appeared previously suitable for rocks, coals and crude oils have been tested for the recognition of rank levels of condensates. MPI and DMPI exhibit a remarkedly similar evolution which allows the differentiation of the samples analysed in these works. Such studies extend the applicability of alkylaromatic hydrocarbon ratios to the characterization of maturity level of condensates which range from immature-marginally mature to overmature samples, partially biodegraded or not.

Oxidation catalysis in a supercritical fluid medium

The supercritical fluid (SCF) extraction technique was extended by its application to SCF-solid catalyzed reactions that otherwise take place in a two-fluid-phase reactor. Using CO/sub 2/ as a solvent, an alkylaromatic hydrocarbon such as toluene was contacted with air in the presence of solid metal redox or acid catalysts, and underwent partial oxidation to benzaldehyde, benzyl alcohol, and cresols. This process should result in more rapid rates of mass transfer and intrinsic reaction than is customary for such reactions at conventional conditions, and more efficient quenching of the oxidation at the desired products; in addition it should allow an easier product separation and a decrease in reaction temperature that will improve the yield to desired products.

Catalytic synthesis of alkylaromatic hydrocarbons from ethane and benzene

Catalytic synthesis of alkylaromatic hydrocarbons from ethane and benzene

ChemInform Abstract: Dealkylation of Alkyl‐Aromatic Hydrocarbons. Part 2. Dealkylation of m‐Xylene and a C9 Industrial Aromatic Fraction on Metal Oxide Catalysts.

ChemInformVolume 18, Issue 26 Isocyclic Compounds ChemInform Abstract: Dealkylation of Alkyl-Aromatic Hydrocarbons. Part 2. Dealkylation of m-Xylene and a C9 Industrial Aromatic Fraction on Metal Oxide Catalysts. G. GARDOS, G. GARDOS Dep. Org. Chem., Univ., 6525 ED Nijmegen, NetherlandsSearch for more papers by this authorT. KUN SZABO, T. KUN SZABO Dep. Org. Chem., Univ., 6525 ED Nijmegen, NetherlandsSearch for more papers by this authorM. KOVACS, M. KOVACS Dep. Org. Chem., Univ., 6525 ED Nijmegen, NetherlandsSearch for more papers by this authorE. ALMASINE BUZAS, E. ALMASINE BUZAS Dep. Org. Chem., Univ., 6525 ED Nijmegen, NetherlandsSearch for more papers by this author G. GARDOS, G. GARDOS Dep. Org. Chem., Univ., 6525 ED Nijmegen, NetherlandsSearch for more papers by this authorT. KUN SZABO, T. KUN SZABO Dep. Org. Chem., Univ., 6525 ED Nijmegen, NetherlandsSearch for more papers by this authorM. KOVACS, M. KOVACS Dep. Org. Chem., Univ., 6525 ED Nijmegen, NetherlandsSearch for more papers by this authorE. ALMASINE BUZAS, E. ALMASINE BUZAS Dep. Org. Chem., Univ., 6525 ED Nijmegen, NetherlandsSearch for more papers by this author First published: June 30, 1987 https://doi.org/10.1002/chin.198726128AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume18, Issue26June 30, 1987 RelatedInformation

AIPO 4-supported nickel catalysts : VII. Adsorption of alkylaromatic hydrocarbons by gas chromatography

The adsorption of alkylaromatic hydrocarbons (normal series: Me, Et, n-Pr, and n-Bu; α-methylated series; Me, Et, i-Pr and t-Bu) has been studied, with 20 wt% nickel supported on AlPO 4, SiO 2, and Al 2O 3 catalysts by using a gas-solid chromatographic technique. Isosteric adsorption heats at low (zero) coverage (Δ H ads o), determined by measuring the retention volume of the adsorbate at different column temperatures, show that the adsorption process is exothermic (δ H ads o < 0). The Gibbs standard adsorption free energies (Δ G ads o) and standard molar adsorption entropies (Δ S ads o) are determined from the values of the Henry's law adsorption constants and show that the adsorption process is nonspontaneous (Δ G ads o > 0) and that the alkylaromatic hydrocarbons lose vibrational and rotational freedom in their adsorption on the catalyst surface (Δ S ads o < 0). In all cases the relative Henry's adsorption constants fit the Taft-Pavelich equation: log [ ( K Γ , p ) i / ( K Γ , p ) 0 ] = ρ * σ * + δ Es .

Solvation of alkylaromatic hydrocarbons towards a paramagnetic relaxation reagent, tris(acetylacetonato)chromium(III)

AbstractA 13C electron–nuclear spin–lattice relaxation study showed that the interaction between alkyl‐substituted aromatics and a paramagnetic relaxation reagent, tris(acetylacetonato)chromium(III), is purely electrostatic, i.e. of a dipole–dipole or dipole–induced dipole type. Except for aromatics having bulky alkyl groups, the preferred chelate position is close to the positive end of the dipole, i.e. close to the α‐position. However, the major electron–nuclear mechanism is non‐specific, and the relaxation rate is mainly controlled by the mutual translational/rotational diffusion of the two species. Paramagnetic shifts induced on addition of Cr(acac)3 support the suggested interaction mechanism.

Adsorption of alkylaromatic hydrocarbons on AlPO 4, Al 2O 3, and SiO 2 catalysts

The adsorption of alkylaromatic hydrocarbons (normal series (R = Me, Et, n-Pr, and n-But) and α-methylated series (R = Me, Et, i-Pr, and t-But)) on AlPO 4, Al 2O 3, and SiO 2 catalysts have been studied using a gas-solid chromatographic technique. Adsorption heats at low (zero) coverage have been determined by measuring the retention volume of the adsorbate at different column temperatures while Δ G and Δ S values were calculated from the Δ H together with the adsorption constants ( K Γp). The adsorption process was exothermic (Δ H < 0) and nonspontaneous (Δ G > 0). In both cases, the relative adsorption constants fit the Taft equation log(K Γp ) i (K Γp ) 0 = ρ ∗σ ∗ + δE s , electrical effects being the primary influence in the α-methylated series while steric effects went into action only in the normal series.

A Review of Unique Male Rat Hydrocarbon Nephropathy

There is a diverse group of hydrocarbons that induce a specific spectrum of nephropathic alterations. Examples include decalin, an alicyclic hydrocarbon; JP5 jet fuel, a mixture of C12-15 straight and branched chain hydrocarbons; C10-11 isoparaffinic hydrocarbons; Stoddard solvent, a mixture of straight and branched-chain paraffins, naphthenes, and alkyl aromatic hydrocarbons; 2,2,4-trimethylpentane, a branched chain hydrocarbon and d-limonene, an aromatic hydrocarbon. Only male rats develop kidney alterations upon exposure to these chemicals. Other mammals such as female rats, mice, guinea pigs, dogs and monkeys evidently are refractory to kidney injury upon exposure. The primary effect of decalin is to specifically exacerbate the accumulation of alpha 2 mu-globulin, a unique protein occurring spontaneously in proximal convoluted tubular epithelial cells only in the mature male rat. Thus, the male rat hydrocarbon nephropathy should not be predictive of a normal human renal response.

The synthesis of alkyl aromatic hydrocarbons and its geochemical implications

In the present study clay minerals have been shown to catalyse alkylation at 200–270°C of substituted benzenes and naphthalenes by alcohols and esters that are known to occur naturally in sediments. It has also been demonstrated that the formation of CC and CO bond linkages under these experimental conditions is accompanied by some dealkylation of alkyl aromatic products. It therefore seems likely that alkyl aromatic compounds may be synthesized during the thermal treatment of coal. Consequently the significance, in relation to coal structure, of the occurrence of such compounds in the products of coal liquefaction, in artificial maturation experiments and in situations where pyrolytic analytical techniques are used requires re-examination. The value of alkyl aromatics as biomarkers for sedimentary maturation processes is questionable when thermal processes have been used in their separation and identification.

4555311 Integrated fractionation in the recovery of alkylaromatic hydrocarbons : Dennis Ward assigned to UOP Inc

4555311 Integrated fractionation in the recovery of alkylaromatic hydrocarbons : Dennis Ward assigned to UOP Inc

New aromatic biomarkers and possible maturity indicators found in New Albany Shale extracts

Aromatic hydrocarbons from benzene extracts of New Albany Shale were characterized. A biomarker that has a molecular weight of 546 and a structural configuration consistent with that of an alkyl-aromatic hydrocarbon (C 40H 66) was tentatively identified. It was found that the relative concentrations of the biomarker are indicative of differing levels of thermal maturity of the shale organic matter. A 40-carbon bicyclic carotenoid (C 40H 48) is proposed as the geochemical precursor of this biomarker. Thermal maturity of the shale organic matter can also be differentiated by observing differences in “fingerprints” as obtained by field-ionization mass spectrometry on the aromatic hydrocarbon fraction. Using this technique, we found that the more mature shale samples from southeastern Illinois contain more low molecular weight extractable aromatic hydrocarbons and the less mature shale samples from northwestern Illinois contain more high molecular weight extractable aromatic hydrocarbons. It was demonstrated that field-ionization and tandem mass spectrometric techniques through fingerprint and individual compound identification, are useful for shale aromatic hydrocarbon fraction characterization and for thermal maturation interpretation.

Uranium-bearing stratiform organic matter in paleoplacers of the lower Huronian Supergroup, Elliot Lake--Blind River region, Canada.

The Elliot Lake-Blind River, Ontario, paleoplacer deposits in the basal Matineda Formation, lowermost member of the 2.25-2.45 Ga old Huronian Supergroup, contain organic matter chemically consistent with kerogen. This substance is also referred to as thucholite. Uranium ores and some gold occur here, and these minerals may be in close association with the kerogen. Two uraniferous and auriferous stratiform kerogens, obtained from the Denison Mines Limited's Denison mine and Rio Algom Limited's Stanleigh mine, have been analyzed by combined high-vacuum pyrolysis--gas chromatography--mass spectrometry and by neutron activation. The reflectances of these samples have also been determined. Related samples containing dispersed kerogen have been examined by backscattered scanning electron microscopy. The polymer-like matrix of the two stratiform kerogens consists of aromatic, alkyl aromatic hydrocarbon, and sulphur moieties and contains 20 and 32% uranium with gold abundances in the parts per billion range. The reflectances of the two kerogens are generally higher than those of the dispersed kerogens; the atomic H/C ratios of the former are approximately 0.6 and approximately 0.4. Backscattered scanning electron microscopy and petrographic observations reveal a complex diagenetic history. Stratigraphic position and supportive analytical data suggest that the stratiform kerogens were probably derived from ancient mats of cyanobacteria, subjected to various radiation-induced reactions, and, at least in part, were affected in a manner similar to the surrounding rocks. The latter experienced physical and chemical diagenetic reactions, which often caused repeated mineral fracturing and led to the local development of authigenic carbonates and feldspar. Some of the chemical nature and history of the stratiform kerogens resemble those of the Witwatersrand carbon seam kerogen.

AC conductivity of alkylarenelithium complexes in aromatic solvents

Polyamine chelates have been made of the lithium derivatives of a number of alkylaromatic hydrocarbons and the conductivities of their solutions measured. The dependence of the specific conductivity of toluene solutions of chelated benzyllithium on the nature of the amine, and the relation between the p K a of the parent hydrocarbon and the specific conductivity in benzene solution of the chelates of its lithium derivative have been examined. The structures of the conducting species are discussed.

Studies on the Regioselectivities in the Oxidation of Simple Alkyl Aromatic Hydrocarbons by Molecular Oxygen

AbstractThe products of the autoxidation of various simple alkyl aromatic hydrocarbons were reduced by LiAlH4, and the alcohols formed were determined by gas chromatography. In the cases of 2‐phenylbutane, 3‐phenylpentane, and 2‐p‐tolylbutane a considerable fragmentation of the intermediate tertiary alkoxy radicals was proved. On the basis of the analytical results relative reaction rates of the various C–H‐bonds in the hydrocarbons studied were calculated. It is shown that the attack at C–H bonds which are not activated by the aromatic nucleus cannot be neglected and may be of great importance for the kinetics of the oxidation of alkyl aromatic hydrocarbons.

Isomerization of alkylaromatic hydrocarbons of aluminosilicate catalysts modified with composite compounds of nickel and copper: N. S. Kozlov, Ye. S. Osinovik, N. Ya. Pryakhina, G. M. Sen'kov and M. F. Gorbatse vich, Neftekhimiya 25, No. 2, 163–166, 1985

Isomerization of alkylaromatic hydrocarbons of aluminosilicate catalysts modified with composite compounds of nickel and copper: N. S. Kozlov, Ye. S. Osinovik, N. Ya. Pryakhina, G. M. Sen'kov and M. F. Gorbatse vich, Neftekhimiya 25, No. 2, 163–166, 1985

Determination of relative Autoxidation Rates of Simple Alkylaromatic Hydrocarbons by competitive reactions

Relative rates of oxidative attack at the CH bonds in α‐position to the aromatic nucleus were determined for 10 simple alkylaromatic hydrocarbons. The results obtained by competitive oxidations of binary mixtures were shown to be consistent. From these results and the regioselectivity data already published, relative reactivities referring to the tertiary CH bond of cumene were calculated for all CH bonds of the hydrocarbons studied.As expected, p‐alkyl groups increase the reactivity of CH bonds in α‐position to the aromatic nucleus. On the other hand, large alkyl groups, bound to the α‐C atoms, decrease the reactivity of the α‐CH bonds.

Role of structural factors and acidity in conversions of alkylaromatic hydrocarbons on high-silica zeolites

1. On high-silica zeolites of the pentasil family, xylenes are converted to isomerization products with high selectivity. In the presence of wider-pore zeolites, the isomerization is accompanied with a considerable degree of disproportionation, the contribution of which increases with increasing diameter of the zeolite pores. 2. The hydroxyl cover in the pentasils has a far higher thermal stability than in the mordenites; and as a consequence, the pentasils retain high catalytic activities even when heat-treated at 700°C. 3 The acidic centers of zeolites of the pentasil and mordenite types are similar in heats of ammonia adsorption and in their specific activity in xylene conversion.

Long chain alkyl heteroaromatics in coal identified by tandem mass spectrometry

The presence of a series of long chain alkyl aromatic and heteroaromatic hydrocarbons was confirmed in a Utah boghead coal using tandem mass spectrometry. Parent and neutral loss scans were utilized to characterize the complex mixture and daughter scans were used to identify individual components.

Changes in composition of atmospheric resid upon hydrodesulpurization

This article examines an atmospheric resid from Romashkino crude before and after hydrodesulfurization in order to show how high-resolution mass spectrometry (HRMS) can be applied to high-molecular-weight organic sulfur compounds and aromatic compounds. The original atmospheric resid and a hydrodesulfurized boiler fuel were subjected to adsorptive separation into fractions. Results are presented from an investigation of the fractions that are the most complex in composition, the ''heavy aromatic'' concentrates, the yields of which before and after hydrodesulfurization were 35% and 25.8% by weight on the original atmospheric resid. The data indicate that in the process of hydrodesulfurization, the hydrogenation of aromatic rings is followed by the splitting of the naphthenic rings. The homologue composition was determined along with the group composition. The distribution curves were investigated for the alkyl ions C /SUB n/ H/sup +/ /SUB 2n+1/ in the singlet monoisotope mass spectra. The number of alkyl substituents on the ring from the structure of the mass spectrum in the region of pseudomolecular ions is calculated. It is concluded that in the hydrodesulfurization of an atmospheric resid from Romashkino crude, hydroaromatic hydrocarbons and polythiaalkanes are removed, and alkylaromatic hydrocarbons and derivatives of pyrene, chrysene, benzothiophene, and dibenzothiophene are accumulated.