Showing papers on "Aromatic hydrocarbon published in 1993"

Method of removing gel forming materials from methylaluminoxanes

Abstract: Gel and gel forming materials are removed from methylaluminoxane by mixing an aromatic hydrocarbon solvent solution of the methylaluminoxane with an aliphatic hydrocarbon solvent and then separating the precipitated solids from the methylaluminoxane solution.

Oxidation of biphenyl by a multicomponent enzyme system from Pseudomonas sp. strain LB400.

Abstract: Pseudomonas sp. strain LB400 grows on biphenyl as the sole carbon and energy source. This organism also cooxidizes several chlorinated biphenyl congeners. Biphenyl dioxygenase activity in cell extract required addition of NAD(P)H as an electron donor for the conversion of biphenyl to cis-2,3-dihydroxy-2,3-dihydrobiphenyl. Incorporation of both atoms of molecular oxygen into the substrate was shown with 18O2. The nonlinear relationship between enzyme activity and protein concentration suggested that the enzyme is composed of multiple protein components. Ion-exchange chromatography of the cell extract gave three protein fractions that were required together to restore enzymatic activity. Similarities with other multicomponent aromatic hydrocarbon dioxygenases indicated that biphenyl dioxygenase may consist of a flavoprotein and iron-sulfur proteins that constitute a short electron transport chain involved in catalyzing the incorporation of both atoms of molecular oxygen into the aromatic ring.

Comprehensive absorption, photophysical/chemical, and theoretical study of 2-5-ring aromatic hydrocarbon diones

Abstract: Absorption spectra, laser flash transient and emission spectroscopy, and all-electron theoretical have been caried out for 16 parent ortho and para aromatic hydrocarbon diones. Also eight variously substituted benz[α]anthracene-7,12-diones have been examined. The effect of ring annelation and geometry and type of dione (ortho or para) has been evaluated for all the areas of concern noted above. Assignment of the orbital nature of the lowest triplet state has been accomplished based on hydrogen atom extraction from the solvent

Process for the Production of Polyethylene

Abstract: A process for the polymerization of ethylene or a mixture comprising ethylene and one or more alpha-olefins and, optionally, a diene, comprising passing, under polymerization conditions, the aforementioned monomer(s) into contact with a catalyst system comprising: (a) the reaction product of (i) a titanium based catalyst precursor having the formula MgaTi(OR)bXC (ED)d wherein ED is an electron donor R is an aliphatic or aromatic hydrocarbon radical having 1 to 14 carbon atoms or COR' wherein R' is an aliphatic or aromatic hydrocarbon radical having 1 to 14 carbon atoms; each OR group is the same or different; each X is independently chlorine, bromine, or iodine; a is 0.5 to 56; b is 0, 1, or 2; c is 2 to 116; and d is 2 to 85; and (ii) at least one activator having the formula Al(R')eX'fHg wherein X' is Cl or OR" R' and R" are the same or different and are saturated hydrocarbon radicals having 1 to 14 carbon atoms f = 0 to 1.5 g = 0 or 1 e+f+g = 3; and (iii) an alkyl, alkoxy, aryl, or aryloxy phosphine oxide, or mixtures thereof, in an amount sufficient to replace about 1 to about 80 mole percent of the electron donor in the precursor, and in a molar ratio of phosphine oxide to titanium of 0.1:1 to 8:1 wherein component (a) is impregnated into an inorganic support; and (b) a hydrocarbyl aluminum cocatalyst.

Aromatic hydrocarbon‐degrading bacteria in the petroleum‐rich sediments of the guaymas basin hydrothermal vent site: Preference for aromatic carboxylic acids

Abstract: Hydrocarbon‐degrading bacteria in freshly collected petroleum‐rich Guaymas Basin sediments were enumerated on mineral base media separately containing naphthalene, biphenyl, or the aromatic carboxylic acids benzoate, p‐hydroxy‐benzoate, mandelate, salicylate, phenylacetate, phthalate, or hydrocinnamate. The total numbers of bacteria were about 2 orders of magnitude higher on the carboxylic acid media than on the two aromatic hydrocarbons, averaging 105 versus 103 bacteria per gram of sediment. Of 151 isolates of aerobic, mesophilic marine bacteria, 124 grew exclusively on one or more of the aromatic carboxylic acids. The remaining 27 isolates used either naphthalene, biphenyl, dibenzofuran, toluene, or phenanthrene and various combinations of aromatic carboxylic acids. A similarity analysis of 135 of the isolates on the basis of substrate use, sodium chloride requirement, and growth on complex organic marine media identified 91 metabolically different bacterial strains: 21 belonging to the group ...

Phenol terminated diester compositions derived from dicarboxylic acids, polyester polymers or alkyd polymers, and curable compositions containing same

Abstract: The present invention is directed towards a process for preparing non-liquid crystalline phenol-terminated diester compositions characterized by the structure of formula 1: ##STR1## wherein R is an aliphatic divalent hydrocarbon radical containing 2 to 40 carbon atoms or a mixture of such radicals, provided however that R contains at least about 8 carbon atoms when n is 0 and p is 0, R1 is an aliphatic or cycloaliphatic hydrocarbon radical containing 2 to 40 carbon atoms or a mixture of such radicals, R2 is an aliphatic, aromatic or a mixture of aliphatic and aromatic hydrocarbon radicals having from 2 to 40 carbon atoms, A is divalent aromatic radical selected from the group consisting of phenylene, naphthylene or his phenylene, p is 0 or 1, n is 0 or an integer ranging from 1 to about 40, provided however, that p is 0 when n is 0 and p is 1 when n is an integer. The invention is also directed to a single stage direct esterification or multi stage esterification processes for producing the aforementioned diesters of formula 1 either with or without the use of esterification catalysts, and is particularly directed to such processes for preparing diesters of reduced color using a low temperature process in combination with catalyst systems containing a phosphorous acid or derivative thereof.

Polysila analogs of aromatic hydrocarbon ions: Structures and energies of Si3H3+, Si4H 42+, and Si5H5−

Abstract: Silicon analogs of aromatic monocyclic ions, (SiH) 3 + (4), (SiH) 4 2+ (5), and (SiH) 5 - (6) have been studied ab initio at Mp2(full)/6-31G * . The D 3h structure of Si 3 H 3 + is the global minimum, whereas other two ions are nonplanar. The D 2d structure of (SiH) 4 2+ is less folded than the carbon analog and possesses a higher stabilization energy. Stabilization energies for the monocharged ions are diminished with respect to the corresponding carbons

Method for partially hydrogenating a monocyclic aromatic hydrocarbon

Abstract: Disclosed is a method for partially hydrogenating a monocyclic aromatic hydrocarbon to produce a cycloolefin, comprising reacting a monocyclic aromatic hydrocarbon with hydrogen in the presence of a particulate hydrogenation catalyst comprised mainly of metallic ruthenium, in a reaction system comprising a continuous aqueous phase having the particulate hydrogenation catalyst suspended therein, an oil phase containing the monocyclic aromatic hydrocarbon, and a gaseous phase comprising hydrogen gas, while applying a shearing force to the reaction system at a specific maximum shear rate. By the method of the present invention, not only can a cycloolefin be produced at high selectivity and in high yield, but also the catalytic activity can be stably maintained at a high level for a prolonged period of time.

Variable-temperature study of aromatic hydrocarbon triplet-state quenching by molecular oxygen in solution

Abstract: The temperature dependence of the bimolecular rate constant for O 2 ( 3 Σ g ) quenching of a series of aromatic hydrocarbon triplet states, κ T ox , has been determined in toluene. Highly curved Arrhenius plots were obtained, indicating a change in rate-determining step over the available temperature range. At low temperatures, κ T ox of all hydrocarbons approached a common limiting slope that was consistent with 4 / 9 κ d . At higher temperatures, low positive or negative activation energies were observed, indicating the involvement of exciplex intermediacy in the overall quenching process

Mordenite catalysts in toluene synthesis

Abstract: In accordance with the the present invention, there is provided a process for the conversion of aromatic hydrocarbons including benzene to hydrocarbon components comprising primarily toluene. According to the invention, a catalyst reaction zone is established having a metal-loaded mordenite catalyst. A mixed feedstock of aromatic hydrocarbons, including benzene, xylene(s) and, optionally, ethylbenzene is introduced into the reaction zone and hydrogen is used as a cofeed to provide a reductive environment. The feedstock is contacted with the metal-loaded mordenite catalyst and the conversion of the aromatic hydrocarbon components is conducted under temperature and pressure conditions sufficient to effect the conversion of the feedstock to hydrocarbon components containing primarily toluene. Finally, the conversion product containing primarily toluene is recovered from the reaction zone.

Grease composition for high-temperature, high-speed and high-load bearings

Abstract: A grease composition for high-temperature, high-speed and high-load bearings comprises (i) a lubricating base oil composed of an alkyldiphenyl ether lubricant as an essential ingredient and having a kinematic viscosity of 90-160 cSt at 40° C., and (ii) 22-30 wt. %, based on the grease composition, of a diurea compound as a thickener. The diurea compound is represented by the following formula: ##STR1## wherein R 2 means an aromatic hydrocarbon group having 6-15 carbon atoms, R 1 and R 3 denote an aromatic hydrocarbon group having 6-12 carbon atoms or a linear alkyl group having 8-20 carbon atoms, and the proportion of aromatic hydrocarbon groups in R 1 and R 3 is 70-95 mole %. The NLGI thickness grade of said composition is in a range of from No. 1 to No. 3.

Method for producing coupled asymmetric polymers

Abstract: A process for preparing a coupled asymmetric block copolymer of a vinyl aromatic hydrocarbon and a conjugated diene which comprises: (a) adding sufficient anionic polymerization initiator to the vinyl aromatic hydrocarbon monomer to start polymerization of the vinyl aromatic hydrocarbon, (b) polymerizing the vinyl aromatic hydrocarbon for a time sufficient to form a first set of vinyl aromatic hydrocarbon blocks having a desired molecular weight, (c) adding sufficient anionic polymerization initiator to start polymerization of a second set of vinyl aromatic hydrocarbon blocks, (d) completing the polymerization of the vinyl aromatic hydrocarbon for a time such that the first set of vinyl aromatic hydrocarbon blocks continues to grow to the desired molecular weight and the second set of vinyl aromatic hydrocarbon blocks grows to a desired smaller molecular weight, (e) adding a conjugated diene and polymerizing it on the ends of the vinyl aromatic hydrocarbon blocks for a time sufficient to form vinyl aromatic hydrocarbon-conjugated diene arms of the desired molecular weight, and (f) adding a coupling agent and coupling the arms to form the asymmetric block copolymer.

Excess Volumes of Mixtures of Alkanols with Aromatic Hydrocarbons

Abstract: The excess volumes of twenty binary mixtures of four aromatic hydrocarbons (benzene, toluene, ethylbenzene, and p-xylene) and five linear alkanols (methanol, ethanol, 1-propanol, 1-butanol, and 1-pentanol) at 20 °C are reported. The excess volume of systems with the same alkanol increases 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 alkanols. The dependence of ∆V/φ1ϑ2 values on composition is noticeably asymmetric. Systems with benzene as one of the component show larger ∆V/φ1ϑ2 values than other systems and systems with methanol show different compositional dependence patterns.

Process for producing monoalkenyl aromatic hydrocarbon compound

Abstract: There is disclosed a process for producing a monoalkenyl aromatic hydrocarbon compound (e.g. 5-(o-tolyl)-2-pentene) which comprises the steps of alkenylating a side chain of an aromatic hydrocarbon compound having at least one hydrogen atom bonded to α-position of the side chain (e.g. alkylbenzene) by the use of a conjugated diene having 4 to 5 carbon atoms (e.g. 1-3 butadiene) in the presence of an alkali metal-based catalyst supported on a carrier; removing at least part of the catalyst from the resultant reaction product by separating the same; inactivating and optionally removing the catalyst contained in the reaction product; and thereafter distilling the reaction product in liquid form to separate and recover the objective monoalkenyl aromatic hydrocarbon compound. By virtue of using the above specific method, the process can prevent the change in quality and property of the objective product even during atmospheric distillation, produce the objective product with high purity in high recovery rate and operate a distillation column during a long stable period of time.

Curing agent for epoxy resin and epoxy resin composition

Abstract: PURPOSE:To provide the subject composition composed of a synthetic resin having a specified structure and capable of producing a cured material excellent in water resistance. CONSTITUTION:The objective curing agent is composed of a synthetic resin obtained by adding H on the aromatic ring of (A) an aromatic hydrocarbon (e.g. phenol or 2-naphthol) containing a phenolic hydroxyl group to alpha-position carbon of (B) a compound (preferably divinylbenzene) containing two or more ethylenic unsaturated double bonds and adding beta-position carbon of the opened ethylenic unsaturated double bond of the component (B) to the carbon on the aromatic ring becoming empty following addition of the ethylenic unsaturated double bond of the component (B) to the alpha-position carbon. This curing agent is obtained by blending the component (B) preferably in an amount of 0.5-0.8mol based on the component (A), adding styrene, etc., thereto and reacting the resultant mixture in the presence of a catalyst such as hydrochloric acid in an organic solvent such as toluene.

Fluorine-modified silicone derivative, its production and cosmetic containing the same derivative

Abstract: PURPOSE: To readily and simply produce a new fluorine-modified silicone derivative exhibiting high water and oil repellency and useful, e.g. for a cosmetic excellent in feeling in use by reacting a polysiloxane partly containing SiH groups with a perfluoroalkyl group-containing unsaturated compound. CONSTITUTION: A silicone derivative containing polysiloxane units respectively represented by formula I (R 1 is 1 to 20C aliphatic hydrocarbon, a 5 to 10C alicyclic or aromatic hydrocarbon; p is 1 to 200) and formula II (R 2 and R 3 are the same kind as R 1 ; q is 0 to 200) is reacted with a perfluoroalkyl compound expressed by formula III [Rf is a 1 to 20C perfluoroalkyl or an ω- perfluoroalkyl represented by formula H(CF 2 ) r (r is 1 to 20); X is single bond, CO, a 1 to 6C divalent hydrocarbon, etc.; Y is CO, a 1 to 6C divalent hydrocarbon, etc.; m is 2 to 16], thus readily and simply producing the objective fluorine- modified silicone derivative containing polysiloxane units respectively represented by formulae IV and I and exhibiting high water and oil repellency. COPYRIGHT: (C)1994,JPO&Japio

Grease composition for bearing used under high-temperature, high-speed and high-load conditions

Abstract: PURPOSE:To obtain the title composition prevented from undergoing initial leakage under high-temperature and high-speed conditions and early seizure under high-load conditions by mixing an alkyldiphenyl ether oil with a specified lubricating base oil and a thickener to obtain a mixture of a specified consistency. CONSTITUTION:A lubricating base oil (e.g. mineral oil) having a kinematic viscosity of 90-160cSt at 40 deg.C and consisting essentially of at least 50wt.%, based on the base oil, alkyldiphenyl ether oil (obtained by the addition reaction of diphenyl ether with a 10-22C alpha-olefin) is mixed with 22-30wt.% diurea compound of the formula (wherein R2 is a 6-15C aromatic hydrocarbon groups; R1 and R3 are each a 6-12C aromatic hydrocarbon group or an 8-20C linear alkyl group, and the content of R1 and R2 which are aromatic hydrocarbon groups is 70-95mol%) (e.g. one obtained from TDI, p-toluidine and octylamine), and 0.1-10wt.% each of an organic sulfonate as a rust preventive, a nitrate and a nonionic surfactant of an HLB of 1.5-9 to obtain a mixture of an NLGI consistency in the range of No.1 to No.3.

A method of producing a 2,4'-dihydroxydiphenylsulfone

Abstract: High purity 2,4'-dihydroxydiphenylsulfones useful as developers for thermal recording paper can be produced efficiently and with high selectivity by reacting one or more phenols and sulfuric acid in the presence as of at least one of phosphonic acid, phosphinic acid and salts thereof, in the absence of a solvent or in the presence of an aromatic hydrocarbon solvent having a boiling point at atmospheric pressure of 130° to 200° C, and then purifying the thus-produced crude 2,4'-dihydroxydiphenylsulfones using a mixed solvent containing (1) 5 to 20 weight % of at least one lower aliphatic alcohol and 95 to 80 weight % of at least one aromatic hydrocarbon which does not contain halogen, (2) 10 to 40 weight % of at least one ketone and 90 to 60 weight % of at least one aromatic hydrocarbon which does not contain halogen or (3) 10 to 40 weight % of at least one ester of acetic acid and 90 to 60 weight % of at least one aromatic hydrocarbon which does not contain halogen

Method of comprehensive utilization of condensed oil

Abstract: This invention uses the gas condensate in petroleum production as raw material to make various hydrocarbon solvents, especially to extract solvent oil, to develop the usage of gas condensate, to increase the yield of hydrocarbon solvents and to realize industrial production of fine extracting solvents (No.6-A), (No.6-B), and (No.6-C). The features of this invention are: the fractionation refining is carried out at normal pressure and lower temperature and the gas-phase fraction of extracting solvent is hydrogenated. Unsaturated hydrocarbon and aromatic hydrocarbon may be removed by hydrogeration reaction which can convert them into cyclohexane under the presense of highly octive and highly selective catalyst "NI". After it is washed the qualified product is yielded.

Process for producing a monoalkenyl aromatic hydrocarbon compound

Abstract: There is disclosed a process for producing a monoalkenyl aromatic hydrocarbon which comprises alkenylating a side chain of an aromatic hydrocarbon compound having at least one hydrogen atom at the α-position of a side chain (such as o-xylene) with a conjugated diene having 4 or 5 carbon atoms in the presence of a catalyst slurry prepared by adding an aromatic hydrocarbon compound to a catalyst comprising a alkali metal and an alkali metal compound. In the aforementioned process, it is particularly effective that the catalyst slurry is prepared by adding the aromatic hydrocarbon compound after the aromatic hydrocarbon compound has been deoxygenated and dehydrated by distillation, and the catalyst slurry thus prepared is supplied to the reaction system. According to the aforementioned process, an industrially useful monoalkenyl aromatic hydrocarbon compound, such as a monoalkenylbenzene, can be produced at a high selectivity, in a high yield, and with enhanced safety and stability for a long time.

Method of producing an oxygen barrier coating containing trimethoxysilyl functional pentadienoate

Abstract: A composite films which exhibit low oxygen transmission rates. The film comprises a silane resin coated on a plastic substrate then cured by ultraviolet radiation. For the silane coating, this invention relies on a class of organosilicon compounds derived from 1) organohydrogensilanes or organohydrogensiloxanes and 2) propargyl esters of carboxylic acids containing a terminal aromatic hydrocarbon radical, where the carbopropynoxy group of the ester and the aromatic hydrocarbon radical are separated by at least two adjacent ethylenically unsaturated carbon atoms. If more than two of these carbon atoms are present they form a sequence of conjugated ethylenic double bonds which allows the polymer to cross-link upon exposure to ultraviolet radiation.

Kinetics of the reactions of carbene (CH2) (X3B1) with selected polycyclic aromatic hydrocarbons at temperatures between 296 and 690 K

Abstract: The kinetics of the reactions of CH 2 radicals in their X~ 3 B 1 ground electronic state with the aromatic hydrocarbon molecules benzene (1), naphthalene (2), phenanthrene (3), anthracene (4), and biphenyl (5) have been studied. Experimental measurements were carried out for reactions 2-5 at temperatures between 445 and 690 K using an isothermal discharge flow system with far-infrared laser magnetic resonance (FIR-LMR) detection of the CH 2 radicals. The results of these investigations as well as those of an earlier study of the rate constant of reaction 1 in the temperature range 296 K≤T≤683 K were analyzed in light of recent temperature-dependent data on the competing reactions of CH 2 (a 1 A 1 )

Process for decreasing chlorine content of chlorinated hydrocarbons

Abstract: The chlorine or halide content in a chlorinated hydrocarbon or halogenated aromatic hydrocarbon in an environment which admits to the presence of air and moisture can be reduced by bringing the chlorinated hydrocarbon or halogenated aromatic hydrocarbon into contact with a reagent which comprises (i) a complex of a substantially nontoxic metal having at least two oxidation states and (ii) a reducing agent which reductively returns the complex from its second oxidation step to its first oxidation stage. A representative embodiment involves bis-(θ5-cyclopentadienyl)titanium dichloride and sodium tetrahydridoborate. Optionally, the reaction is conducted in the presence of an aliphatic or aromatic amine, optionally in the presence of an inert organic solvent.

Method for optical resolution of 2-arylpropionic acid compound

Abstract: PURPOSE:To obtain an optically active 2-arylpropionic acid by optical resolution of a racemic 2-arylpropionic acid compound using a specific optical antipode as a resolving reagent. CONSTITUTION:A racemic 2-arylpropionic acid compound of the formula [Ar is (substituted) aromatic hydrocarbon] is reacted with an optical antipode, as resolving reagent, selected from 1-phenylethylamine and 1-(4-methylphenyl) ethylamine in a solvent (e.g. an acetic ester-water) under cooling to heating. After reaction, the system is agitated at room temperature and the crystal deposited is collected, and the resolving reagent is removed from the crystal through decomposition, thus obtaining the objective optically active 2- arylpropionic acid compound. With a single resolving operation, the aimed compound with highly excellent optical purity can be obtained.