Showing papers on "Aromatic hydrocarbon published in 1992"

Preparation of methylaluminoxanes

Abstract: Soluble methylaluminoxane is prepared by reacting water with a solution of an alkylaluminum compound, wherein at least about half the alkyl groups are methyl groups, in a 1:4 to 4:1 by volume aliphatic hydrocarbon/aromatic hydrocarbon solvent mixture, wherein the aliphatic hydrocarbon solvent has a lower boiling point than the aromatic hydrocarbon solvent, so as to form a product solution of methylaluminoxane in said solvent mixture along with insoluble reaction products which can be removed by filtration. The aliphatic solvent can be removed by vaporization to give a concentrated solution of aluminoxane in the aromatic solvent.

Hydroformylation process and bisphosphite compound used therein

Abstract: A hydroformylation process for preparing a hydroformylated product by reacting an olefinic compound with hydrogen and carbon monoxide in the presence of a Group VIII metal catalyst, in the reaction of which there is present a phosphite compound having the formula (I), A¹⁅O-P(OR¹)(OR²)]n (I) wherein R¹ and R² are respectively an aromatic hydrocarbon group which may be the same or different and the aromatic hydrocarbon group has at least a hydrocarbon group on a carbon atom adjacent to a carbon atom bonded with an oxygen atom as a substituent; A¹ is an n-valent organic group having an aliphatic hydrocarbon group, a cycloaliphatic hydrocarbon group or an aromatic hydrocarbon group bonded with an adjacent oxygen atom, which may respectively have a substituent; n is an integer of from 2 to 4; and the respective ⁅O-P(OR¹)(OR²)] group may be the same or different.

Infrared emission spectra of benzene and naphthalene : implications for the interstellar polycyclic aromatic hydrocarbon hypothesis

Abstract: Emissions from the fundamental region (∼3050 cm −1 , 3.3 μm) of the C-H stretching modes in the small aromatic hydrocarbon benzene (C 6 H 6 ) and naphtalene (C 10 H 8 ) were observed following ultraviolet laser excitation. These two molecules respectively represent the prototype and smallest members of the polycyclic aromatic hydrocarbon (PAH) chemical family, proposed as likely carriers of a set of infrared features widely observed in various dust-containing astronomical sources

Process for the regioselective conversion of aromatics to para-disubstituted benzenes

Abstract: Processes for converting a wide variety of aromatic hydrocarbons, such as polyalkylaromatics, into commercially useful para-substituted aromatics such as para-xylene are disclosed. The aromatic hydrocarbon feed stream is first partially converted into toluene which is then subjected to a highly para-selective methylation process. The present invention therefore provides novel processes and catalysts for increasing the para-selectivity in the selective production of para-substituted aromatic compounds. From the description provided herein, those skilled in the art will appreciate that the catalysts and processes of the present invention provide greater para-selectivity at conversion rates unattained by previously known methods.

Process for producing alkylaromatic lubricant fluids

Abstract: The thermal and oxidative stability of HVI-PAO olefin oligomers is improved by alkylation in the presence of a solid, porous, acidic alkylation catalyst defined by a specific X-ray diffraction pattern. A preferred catalyst is the synthetic zeolite MCM-22. The olefinic oligomers used as alkylating agents are prepared from 1-alkene oligomerization in contact with a reduced metal oxide, preferably reduced chromium oxide, catalyst on support such as silica. Aromatics which may be used in the reaction include monocyclic aromatics such as benzene and toluene as well as bicyclic aromatics such as naphthalene. Substituted aromatics may be used in order to introduce functional groups such as hydroxyl groups into the products, for example by the use of hydroxyaromtics such as phenol or naphthaol. The alkylated aromatic hydrocarbon products retain the unique features of the alkylating olefinic oligomer and exhibit high viscosity index and low pour point as well as improved thermal and oxidative stability and additive solvency characteristics.

Diene polymers and copolymers terminated by reaction with fused-ring polynuclear aromatic compounds

Abstract: A terminally functionalized liquid polymer is prepared by reacting a low molecular weight living diene polymer or copolymer obtained by anionic polymerization of a diene monomer or mixture of a diene monomer and a vinyl aromatic hydrocarbon monomer with a fused-ring polynuclear aromatic compound. The resultant terminally functionalized liquid diene polymers or copolymers can be utilized as dispersants for particulates such as carbon black or graphite and may also be employed as viscosity modifiers for lubricating oils or in electrorheological devices or damping devices.

Diene polymers and copolymers terminated by reaction with aromatic nitriles

Abstract: A terminally functionalized polymer is prepared by reacting a living polymer obtained by anionic polymerization of a diene monomer or mixture of a diene monomer and a vinyl aromatic hydrocarbon monomer with an aromatic nitrile compound. Especially useful aromatic nitriles are the unsubstituted and substituted benzonitriles. The resultant terminally functionalized polymers have reduced hysteresis in the carbon black reinforced and cured state and can be utilized to form elastomer compositions for tire treads having reduced rolling resistance.

Radical cation complexes formed by {pi}-lone pair interactions

Abstract: Time-resolved fluorescence-detected magnetic resonance (FDMR) is used to observe radical cations of thioethers in alkane and aromatic hydrocarbon solvents. Monomeric sulfide radical cations are stabilized at temperatures less than {approximately} 250 K in aromatic solvents such as toluene by electron donation from the solvent. The resulting arene-thioether complex radical cations are examples of mixed complex radical cations involving the interaction between lone-pair and {pi}-orbitals. The solvent interaction inhibits reactions of thioether radical cations (dimer formation and probably proton loss) and retards other radical cation reactions, such as dimer exchange. 39 refs., 7 figs., 4 tabs.

Alkyl aromatic hydrocarbon dehydrogenation catalyst and method for producing the catalyst

Abstract: In order to increase performances of an iron oxide-potassium oxide system catalyst to be used for an alkyl aromatic hydrocarbon dehydrogenation reaction in the presence of steam, there is provided an alkyl aromatic hydrocarbon dehydrogenation catalyst wherein a little amount of titanium oxide is added by the mixing and kneading method or by the preceding addition to iron oxide in the production of the iron oxide-potassium oxide system catalyst to be used for the alkyl aromatic hydrocarbon dehydrogenation reaction in the presence of steam. The iron oxide-potassium oxide system catalyst is allowed to contain a little amount of titanium oxide, whereby an activity can be remarkably increased, as well as a selectivity in the same conversion ratio can also be improved in the alkyl aromatic hydrocarbon dehydrogenation reaction, and further the obtained catalyst exhibits stable performances with time on stream.

High-pressure vapor-liquid equilibrium data for binary mixtures containing molecular nitrogen, carbon dioxide, hydrogen sulfide and an aromatic hydrocarbon or propylcyclohexane in the range 313-473 K

Abstract: Experimental binary vapor-liquid equilibrium data were obtained for mixture of on light component, among nitrogen, carbon dioxide, and hydrogen sulfide, and one heavy component, among tulene, m-xylene, mesitylene, n-propylcyclohexane, and n-propylbenzence. Three static analytical methods differing by the sampling technique and one static synthetic method were used about 313, 393, and 473 K

Process for isomerizing endo-form of aromatic group-containing norbornenes to exo-form thereof, isomer mixture of aromatic group-containing norbornenes and process for preparing same, and ethylene/aromatic group-contain ng norbornene copolymer and process for preparing same

Abstract: A process for isomerization of an endo-form of aromatic group-containing norbornenes represented by the following formula (I) to an exo-form which comprises bringing the endo-form into contact with a solid acid catalyst. wherein p is 0 or an integer of 1 or more, q and r are each 0,1 or 2, R1 to R15 are each independently hydrogen or halogen atom, aliphatic hydrocarbon group, aromatic hydrocarbon group or alkoxy group, R5 (or R6) are R9 (or R7) may be linked together through an alkylene group of 1-3 carbons or may be directly linked together.

Catalyst for the production of aromatic hydrocarbons and process for producing aromatic hydrocarbons by the use thereof

Abstract: There are disclosed a catalyst obtainable by the simple manufacturing process, having a high and persistent catalytic activity for a long-term production of aromatic hydrocarbon and a process for efficiently producing aromatic hydrocarbons from nonaromatic hydrocarbon by the use of the catalyst. The catalyst comprises L-type zeolite with both platinum components and halogen components simultaneously supported thereon, and is capable of producing aromatic hydrocarbons over a long-term stable operation with a high yield and high activity.

Hydrogenated vinyl aromatic hydrocarbon polymer composition and optical disc substrate

Abstract: A hydrogenated vinyl aromatic hydrocarbon polymer comprising: (a) 5 to 90% by weight of a vinyl aromatic hydrogenated polymer (A) obtainable by hydrogenating a hydrocarbon-conjugated diene block copolymer in such an amount that substantially all the double bonds derived from the conjugated diene bonds and from 60 mol% to 80 mol% of the double bonds in the aromatic rings have been hydrogenated, the content of the conjugated diene polymer units in the block copolymer being from 1 to 50 wt%; and (b) 10 to 95% by weight of a hydrogenated polymer (B) obtainable by hydrogenating a vinyl aromatic hydrocarbon polymer in such an amount that from 60 mol% to 80 mol% of the double bonds in the aromatic rings have been hydrogenated.

Method for converting light hydrocarbon

Abstract: PURPOSE: To convert a light hydrocarbon consisting essentially of a paraffin into a lower olefin and a monocyclic aromatic hydrocarbon in high yield. CONSTITUTION: Catalytic cracking is carried out by using a zeolite selected from ZSM-5s and ZSM-11 containing an alkaline earth metal in 0.01-0.6 atomic ratio to Al in the zeolite as a catalyst. COPYRIGHT: (C)1994,JPO&Japio

Method of synthesis of block copolymers of vinyl aromatic hydrocarbons and polydimethylsiloxane

Abstract: A method for producing, in the presence of both monomers, a block copolymer of a polymer block of a vinyl aromatic hydrocarbon (and/or a conjugated diene) and a block of polydimethysiloxane which comprises adding a vinyl aromatic hydrocarbon, an organo alkali metal promoter, hexamethylcyclotrisiloxane and a polar promoter to a solvent (or to the styrene if no solvent is to be used) at a temperature of 0° to 60° C., allowing the polymerization of the vinyl aromatic hydrocarbon to proceed until the color of the vinyl aromatic hydrocarbon - Li+ species which is initially produced fades, then raising the temperature to 60° to 120° C. wherein the hexamethylcyclotrisiloxane polymerizes at the end of the polystyrene polymer blocks and then terminating the polymerization.

Swelling characteristics of polymer membranes in the presence of aromatic hydrocarbon liquids

Abstract: Swelling properties of some engineering polymer membranes in the presence of monocyclic aromatic hydrocarbons have been studied from the solvent immersion experiments. The liquids were chosen with varying methyl and methoxy substitutions to study the effect of substitutions on their transport properties. Diffusion coefficients have been extracted from the swelling results. The concentration dependence of diffusion coefficients has been investigated

Preparation of adipic acid by hydrocarboxylation of pentenic acids

Abstract: Adipic acid is selectivity prepared by reacting water and carbon monoxide with at least one pentenic acid, in the presence of a catalytically effective amount of an iridium-based catalyst and at least one iodinated promoter therefor at an elevated temperature, at a pressure greater than atmospheric and in at least one solvent medium which comprises a saturated aliphatic or cycloaliphatic hydrocarbon or halogenated derivative thereof, an aromatic hydrocarbon or halogenated derivative thereof, or an aliphatic, aromatic or mixed ether, and wherein the I/Ir atomic ratio is less than 20.

Excess volume of mixtures of alkanes with aromatic hydrocarbons

Abstract: The excess volumes of 22 binary mixtures of aromatic hydrocarbons and alkanes are reported. The excess volume of systems with the same alkane decreases with increasing size and number of substituents on the benzene ring. For systems with the same aromatic hydrocarbon it increases with the length of the alkanes

Heat-resistant positive photoresist composition

Abstract: PURPOSE:To obtain a heat-resistant positive type photoresist composition, composed of a heat-resistant polyimide-based polymer containing eliminative protecting group and a compound capable of inducing eliminating reaction of the protecting groups and capable of regulating physical properties of the resultant films within a wide range. CONSTITUTION:A positive type photoresist composition is obtained by blending (A) a polymer, prepared by protecting OH groups and, as necessary, COOH groups in an imide-based polymer obtained from a tetracarboxylic acid dianhydride, an OH group-containing aromatic diamine and, as necessary, an aromatic or an aliphatic diamine without OH group with eliminative protecting groups (preferably tetrahydropyranyl group or t-butyl group) under acidic or alkaline conditions and consisting essentially of structural units expressed by the formula [R is tetravalent aromatic hydrocarbon group or aliphatic hydrocarbon group; R is (2+n)-valent aromatic hydrocarbon group having one or more OH groups protected with the aforementioned protecting groups; (n) is 0-5] with (B) 5-50wt.% compound (e.g. a diallylsulfonium salt) capable of inducing the eliminating reaction of the aforementioned protecting groups by irradiation with active rays.

Substituted 1-oxy-4-acyloxypiperidine and 1-oxy-4-acylaminopiperidine stabilizers

Abstract: Substituted 1-oxy-4-acyloxypiperidines or 1-oxy-4-acylaminopiperidines of formula I ##STR1## wherein R1, R2, R3 and R4 are independently hydrogen, alkyl or substituted alkyl, R5 is hydrogen, alkyl, cycloalkyl, allyl or benzyl, X is --O-- or --NE--, E is hydrogen, alkyl or cycloalkyl, A is an n-valent aliphatic or aromatic hydrocarbon radical, and n is 1 to 4 are effective in providing melt flow stabilization to polymeric materials during processing.

Catalytic process for selective alkylation of aromatic hydrocarbons

Abstract: A catalytic process for the selective alkylation of mono- and polycyclic aromatic hydrocarbons is described. The aromatic hydrocarbon is reacted with an alkylating agent in the presence of an acid form of a dealuminated small pore mordenite catalyst having an atomic ratio Si/Al of at least 10:1 to thereby yield the desired alkyl substituted derivative with improved selectivity and improved yield.

Jodoniumsalze und verfahren zu deren herstellung.

Abstract: The invention concerns iodinium salts of the general formula A-J-B X, in which A is a group of the general formula (1) in which C is a monovalent aromatic hydrocarbon group with 6 to 14 carbon atoms or a monovalent aromatic hydrocarbon group containing at least one oxygen and/or sulphur atom and with 5 to 14 atoms in the aromatic ring, D, E and F are each substituents of C, D being a group of the formula -(0)x-(R)y-SiR1/3, E being a group of the formula -OR, F being a group of the formula -R, a being 1, 2, or 3, b being 0, 1 or 2, c being 0, 1 or 2, x being 0 or 1 and y being 0 or 1, and R, R, R and R are as defined in claim 1; B is a group of the formula (2) in which E and F, which are as defined above, may each be bound to the 2, 3, 4, 5 or 6 position in the benzene ring, d is 0, 1 or 2, e is 0, 1 or 2 and X is a tosylate anion or a weakly nucleophilic or non-nucleophilic anion Y selected from the group comprising CF3C02, BF4, PF6, AsF6, SbF6, Cl04, HS04 and CF3S03.