Abstract: A process for the manufacture of stockable dense road asphalt that is comprised of materials, having elements of a diameter from essentially zero to 10-30 mm, coated in a cutback or fluidified bitumen-based binder. The materials are separated into at least two granulometries. The first group is a grouping of the smallest elements. The second group is a grouping of the remaining elements. The first group is coated with a first bituminous binder emulsion which is a cationic cutback or fluidified bitumen emulsion with a fracture index greater than zero and having a residual binder viscosity measured on a Standard Tar Viscosimeter (10 mm, 25.degree. C.) of less than 50 seconds. The second group is coated with a second bituminous binder emulsion which is a cationic cutback or fluidified bitumen emulsion with a residual binder viscosity measured on a Standard Tar Viscosimeter (10 mm, 25.degree. C.) of between 1000 and 2000 seconds. Both the coated groups are then mixed together for a few seconds.

Abstract: A process for increasing the content of mesophase in a pitch includes using a high molecular aromatic fraction based on a material selected from the group consisting of coal tar, crude oil and their mixture in molten form, thermally treating the fraction in form of a thin, continously moving film, and removing volatile components by degassing during the thermal treatment. The process distinguishes in using a high molecular aromatic fraction which may contain mesophase, shaping the fraction continuously mechanically to a thin film with a layer of thickness of between substantially 0.

Abstract: A plasticizer for use in the manufacture of pitch which forms a fluid at room temperature consisting essentially of a tar composed of low molecular weight and polymerized aromatic hydrocarbons having a molecular weight distribution characteristic which is bimodel. The plasticizer is formed by reacting a tar or distillate precursor with oxygen under controlled conditions of temperature and time.

Abstract: A process for the production of high quality petroleum tar pitch for use as a binder in the manufacture of electrodes for the aluminum and steel industries from a highly aromatic feed comprises fractionating the feed in an oxygen-free environment under controlled conditions so as to obtain a specific quality petroleum tar pitch.

Abstract: Binder pitch is prepared by combining a petroleum aromatic mineral oil thermal tar and super finely subdivided calcined premium coke particles. The petroleum aromatic mineral oil thermal tar is obtained by hydrotreating, thermally cracking and vacuum distilling an aromatic mineral oil. Additionally, the aromatic mineral oil thermal tar may be subjected to heat soaking.

Abstract: Contrary to known alkylation of pitches, it is disclosed that pitches are modified with particular aromatically substituted and activated C.sub.1 to C.sub.4 alkyl groups. The resulting modified pitches are easily polycondensed and give high coking residues and good mesophase formation. This is achieved on the one hand by dispensing with catalysts, which can be only incompletely removed from the pitch and, on the other hand, by employing reactive short chain alkyl aromatic compounds.

Abstract: A process for co-production of a pitch for the manufacture of HP carbon fibers and a pitch for the manufacture of GP carbon fibers is proposed. The pitch for the manufacture of GP carbon fibers is prepared from the spent fraction not used in the production of an optically anisotropic pitch suitable for the manufacture of HP carbon fibers. The spent fraction has hitherto been discarded as a valueless material. According to the present process, a pitch for the manufacture of so-called ultra HP carbon fibers with tensile strength of over 400 Kg/mm.sup.2 and modulus of elasticity of over 60 ton/mm.sup.2 and a pitch for the manufacture of GP carbon fibers can be produced simultaneously. Both pitches have very excellent spinnability and when they are spun, they cause no fiber cut-off even at a high spinning rate of, for example, 500 m/min or 700 m/min.

Abstract: A process for selectively producing middle distillate fuel products from paraffin waxes such as slack wax and Fischer-Tropsch wax by hydroisomerizing the wax to convert 60-95 weight percent per pass of the 700.degree. F..sup.+ fraction contained in said wax. The catalyst employed is a fluorided Group VIII metal-on-alumina catalyst where the fluoride within the catalyst is present predominately as aluminum fluoride hydroxide hydrate. The preferred Group VIII metal is platinum.

Abstract: A method for the hydrogenation of coal tar pitch which comprises subjecting said coal tar pitch containing toluene insolubles to slight hydrogenation in the presence of a hydrogenation catalyst having carried on a refractory inorganic oxide carrier at least one member selected from the class consisting of elemental metals, belonging to Groups VI B and VIII in the Periodic Table and oxides and sulfides thereof, under the conditions of 280.degree. to 400.degree. C. of reaction temperature, 20 to 200 kg/cm.sup.2. G of hydrogen pressure, 0.1 to 10 hr.sup.-1 of LHSV, and 500 to 2,000 Nl/liter of hydrogen to liquid ratio, and a catalyst therefor. The "slight" hydrogenation is hydrogenation to a degree such that the difference of hydrogen to carbon atomic ratio between the untreated coal tar pitch and the hydrogenated coal tar pitch falls in the range of 0.03 to 0.5.

Abstract: A method for producing graphite structures which are of light weight and excel in elasticity from a carbonaceous material comprises in succession the steps of: (a) treating said carbonaceous material with nitric acid or a nitric-sulfuric acid mixture, (b) bringing the acid-treated carbonaceous material into contact with a basic aqueous solution to make it soluble, (c) adding an acidic aqueous solution to the obtained soluble matter to regulate the pH of said soluble matter to 3 or less, thereby precipitating a carbonaceous component therefrom, and (d) graphitizing the thus precipitated carbonaceous component at 2,400.degree. C. or higher temperature.

Abstract: Asphalt used for road paving containing catalytic cracking catalyst particles which have been burned to remove hydrocarbons deposited thereon during a petroleum catalytic cracking process. The catalyst particles may be present in the asphalt in amounts of from 0.1% to 5.0% by weight of the asphalt, but more preferably from 0.2% to 2.0% by weight of the asphalt. The particles, which are comprised of crystalline and amorphous silica and alumina and silica-alumina combinations, function to prevent oxidative condensation of the asphalt, thus preventing hardening of the asphalt.

Abstract: An improved process for producing an anisotropic pitch product suitable for carbon fiber manufacture. A carbonaceous feedstock substantially free of mesophase pitch is heated for a period of time at an elevated temperature while passing an oxidatively reactive sparging gas such as a mixture of oxygen and nitrogen through the feedstock. The oxidatively treated feedstock is then subjected to a heat soak, for a longer period of time in the absence of a sparging gas. Thereafter the heat soaked feedstock is heated at an elevated temperature in the presence of a non-oxidative sparging gas for a time period equal to or less than the heat soak to produce an anisotropic pitch having from 50 to 100% by volume mesophase which is suitable for producing good quality carbon fibers.

Abstract: In a process for the production of carbon fibers from high boiling bituminous substances in which a purified and polymerized concentrated carbon fiber precursor is spun into fibers which are oxidized and then carbonized and optionally graphitized, the improvement comprising adding to the carbon fiber precursor just before spinning 2 to 10% by weight of a solvent in which the precursor is insoluble or only slightly soluble under normal conditions and mixing the resulting mixture under hypercritical conditions for the solvent for at least 10 minutes without gas or solid inclusions formed in the fiber and neoformatgion of solids is prevented.

Abstract: A method of purification for anethole which involves forming an aqueous emulsion of crude anethole and crystallizing anethole from the emulsion. The process provides a purified anethole having improved odor and taste.

Abstract: A process for preparing a baseoil blend of predetermined coking tendency, and for measuring the effectiveness of additives for reducing coking tendency in baseoils, utilizing the relationship of the content of volatile fractions and how boiling fractions in baseoil to the onset and/or progression of asphaltene formation.

Abstract: An improved process for producing an anisotropic pitch product suitable for carbon fiber manufacture. A carbonaceous feedstock substantially free of mesophase pitch is heated at elevated temperature while passing an oxidatively reactive sparging gas such as air through the feedstock. The oxidatively treated feedstock, which contains isotropic pitch, is solvent fractionated to recover a solid pitch which on fusion becomes an anisotropic pitch product having from 50 to 100 percent by volume mesophase. In one aspect of the invention the carbonaceous feedstock is oxidatively treated in a melt phase at a lower temperature and the resulting isotropic pitch is then heated at a higher temperature in a melt phase in the presence or absence of a non-oxidative sparging gas prior to solvent fractionation.

Abstract: An improved process for producing an anisotropic pitch product suitable for carbon fiber manufacture. A carbonaceous feedstock substantially free of mesophase pitch is heated at elevated temperature while passing an oxidatively reactive sparging gas such as air through the feedstock. The oxidatively treated feedstock, which remains substantially free of mesophase pitch, is then heated at a higher temperature in the presence of a non-oxidative sparging gas to produce an anisotropic pitch having from 50 to 100% by volume mesophase which is suitable for producing good quality carbon fibers.

Abstract: Pitch that is obtained from a condensed polycyclic aromatic hydrocarbon and the content of an optically anisotropic phase in which is substantially 100% is disclosed. This mesophase pitch has a H/C atomic ratio of 0.5-1.0, contains naphthenic carbon in an amount of at least 7% of the total carbon, and has a softening point of 180.degree.-400.degree. C. Fibers melt-spun from this mesophase pitch can be converted to carbon or graphite fibers having high strength and modulus of elasticity by a heat treatment which consists of heating to a temperature of 250.degree.-300.degree. C. in an air atmosphere, then heating to 1,000.degree. C. or higher in an inert gas atmosphere. Such mesophase pitch is produced by polymerizing a condensed polycyclic aromatic hydrocarbon for 5-300 minutes at a temperature of 180.degree.-400.degree. C. and at a pressure of 5-100 atmospheres in the presence of 0.1-20 moles of HF and 0.05-1 mole of BF.sub.3 per mole of the condensed polycyclic aromatic hydrocarbon.

Abstract: Method of producing a baseoil having a reduced coking tendency by removing precursors from the baseoil. Baseoil having reduced coking tendencies which comprises a substantially no coking precursors therein.

Abstract: In a process for the production of carbon fibers from high boiling bituminous substances in which a purified and polymerized concentrated carbon fiber precursor is spun into fibers which are oxidized and then carbonized and optionally graphitized, the improvement comprising just before spinning a supercritical gas is dissolved in mesophase pitch at a pressure of 100 to 350 bars and a temperature up to 150.degree. K. below the melting temperature of the mesophase pitch to form a low viscosity melt, separating the latter into an isotropic phase and an anisotropic carbon fiber precursor and spinning the latter into fibers whereby the spinning temperature is lowered and the mesophase contact is increased due to the viscosity lowering activity of the supercritical gas.

Abstract: A process for improving the deasphalting of a heavy hydrocarbon feedstock with a solvent by subjecting the feedstock to shearing alternatively after and/or before the addition of at least a portion of the solvent to the feedstock is disclosed. Alternative means for effecting the shearing and desired ranges of shear are also disclosed.

Abstract: A method of removing salts from coal tar and coal pitches comprising washing coal tar or coal pitch in a pressure container with water and a carbon dioxide containing gas at a temperature and pressure near the critical point of the gas in the optional presence of at least one member of the group consisting of a solvent and an entraining agent, removing the liquid or dissolved tar or pitch to obtain tar or pitch with a low salt content and removing the aqueous phase whereby all the resins remain in the tar or pitch.

Abstract: A mesophase pitch suitable for carbon fiber production is produced by heat soaking a heavy aromatic hydrocarbon feedstock at conditions such that a substantial part of the feedstock is converted to mesophase pitch. The mesophase pitch is separated from the heat soaked material by settling at a pressure higher than the pressure of the heat soaking step. In one embodiment, separate mesophase pitches having different properties can be recovered from the heat soaked feedstock.

Abstract: A process for the preparation of an excellent mesophase pitch suitable for use as a spinning pitch for the production of high performance carbon fibers is disclosed. The mesophase pitch can satisfy the four remarkable characteristics at the same time, i.e., a softening point of below 320.degree. C. as determined by Mettler method, a mesophase content of above 90% as examined on a polarized microscope, a quinoline insoluble content of less than 20%, and a xylene soluble content of less than 20%. The mesophase pitch is particularly homogeneous and is easily spinnable. The process can be characterized by a preliminary extraction step, a continuous heat treatment step, and an extraction step. In some cases, the preliminary extraction step can be omitted. Graphite fibers having a tensile strength of about 400 Kg/mm.sup.2 and a modulus of elasticity of above 60 ton/mm.sup.2 can be obtained from the mesophase pitch. Further, even carbon fibers prepared at a carbonization temperature of 1000.degree. C.

Abstract: There is disclosed pitch prepared from petroleum pitch, which is normally considered to be inferior to coal tar pitch, which petroleum pitch has properties to equal that of coal tar pitch. That is to say, that the softening points, the Conradson carbon, the toluene insolubles and the quinoline insolubles can be matched with those obtained from coal tar pitch. In addition the properties of the petroleum pitch can be varied to meet end user specifications.

Abstract: A novel optically anisotropic pitch is provided which is produced by thermal modification of a polymer having a structure of an alkylbenzene and a condensed aromatic compound with two to four fused rings bonded to each other via a methylene group.In preferred embodiments, the optical anisotropy is 80% or more. As the alkylbenzene there may be used xylene, trimethylbenzene or tetramethylbenzene. As the condensed aromatic compound with two to four fused rings, there may be used naphthalene, anthracene, phenanthrene, or naphthacene. The polymer starting material may be obtained by the reaction of a xylene formalin resin, mesitylene formalin resin or alkylbenzene and a condensed aromatic compound with two to four fused rings in the presence of a protonic acid as a catalyst.

Abstract: A process for producing an optically anisotropic pitch for use in the production of high performance carbon fibers, wherein a compound represented by the formula (1) as a raw starting material is mixed with one of heavy oils and subjected to thermal modification: ##STR1## wherein m is an integer of 2 or more; R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.6, R.sub.7, R.sub.8, R.sub.9 and R.sub.10 each represents a hydrogen atom, a methyl group or an ethyl group; and R.sub.5 represents a hydrogen atom or a methyl group. The pitch has a softening point which can be set at discretion and excellent molecular orientation.

Abstract: A process for an efficient preparation of a mesophase pitch is disclosed. The process is suitable for the production of high performance carbon fibers, from a coal tar or a petroleum residual oil. More particularly, the present invention relates to a process for the preparation of a homogeneous mesophase pitch which comprises a continuous thermal treatment of a heavy oil or a pitch which does not contain quinoline insoluble fractions, in the presence or absence of an aromatic oil, subsequent distillation of the thermally treated product, recovery of a pitch with extremely low quinoline insoluble contents, hydrogenation of the pitch by continuous thermal treatment in the presence of a hydrogen-donating solvent, distillation and recovery of a hydrogenation pitch, and thermal treatment of the hydrogenated pitch. The mesophase pitch prepared by the process of the present invention is suitable for the production of high performance carbon fibers.

Abstract: A process for producing pitch useful as a starting material for the manufacture of a carbon material is provided. The pitch is produced by polymerizing a condensed nuclear aromatic compound or a material containing the same. The polymerization is carried out in the presence of a hydrogen fluoride/boron trifluoride catalyst system. The condensed nuclear aromatic compounds which may be used in this process are naphthalene, anthracene, phenanthrene, acenaphthene, acenaphthylene, pyrene and mixtures thereof.

Abstract: Mesophase formation is optimized in graphite and coke precursors by a process which includes determining the values of critical chemical parameters for proposed precursors, modifying the precursors by adjusting such critical chemical parameters as oxygen content, aromaticity and functionality to within certain predetermined optimal limits and treating the resulting modified precursors to form mesophase. Oxygen content can be adjusted by oxidation or reduction of the precursor. Aromaticity can be adjusted by suitable heat treatment. Functionality can be adjusted by derivatization.

Abstract: A new composition is disclosed which comprises pellets of asphalt coated with a solid layer of sulfur. The sulfur shell provides a meltable container for the asphalt core while protecting it from contact with the atmosphere. The relative quantities of sulfur and asphalt in the pellets of the invention may be varied over a wide range to provide sulfur-to-asphalt ratios commonly used in both sulfur-asphalt-sand mixes and sulfur-extended asphalt binders. The advantages of pelletizing are virtual elimination of the danger of dealing with hot materials and significant reduction in energy costs associated with keeping asphalt and sulfur hot and pumpable. To produce an asphalt paving mix, the sulfur-coated asphalt pellets may simply be mixed with heated aggregate.

Abstract: A process for producing a pitch useful as a raw material for carbon fibers, which comprises(1) heat-treating at least one starting material selected from the group consisting of a heavy oil obtained by fluid catalytic cracking of a petroleum, a distillate or a residual oil obtained by distilling the heavy oil, and a pitch obtained by heat-treating any of the foregoing materials at a temperature of 350.degree. to 550.degree. C.,(2) separating and removing insoluble substances from the reaction mixture obtained in step (1) to obtain a first treated mixture,(3) heating the first treated mixture obtained in step (2) at a temperature of 250.degree. to 400.degree. C. and removing light fractions which distill at said temperature to obtain a second treated mixture, and(4) treating the second treated mixture obtained in step (3) at a temperature of 430.degree. to 550.degree. C.

Abstract: A method of producing a precursor pitch suitable for the production of carbon fibers, which method includes dissolving a coal tar pitch in a particular solvent to remove a solvent insoluble matter, distilling off the solvent to obtain a purified pitch containing no free carbon, and heat-treating the purified pitch to obtain an objective precursor pitch.

Abstract: A carbonaceous feed, such as a heavy hydrocarbonaceous oil or coal and mixtures thereof, is upgraded by a combination coking and catalytic slurry hydroconversion process which may be integrated with a deasphalting process.

Abstract: A method of producing high quality, homogenous asphalt comprising the steps of mixing and heating a hydrocarbon feedstock not normally suited for asphalt production with elemental sulfur and agitating the resulting mixture. A halide catalyst may be added to the mixture to promote the reaction of the hydrocarbon feedstock with the sulfur. If desired, the agitated mixture may be air blown in any conventional manner to increase its hardness.

Abstract: The present invention provides a process for reducing the pour point of a crude oil by adding a pour-point depressant selected from the group consisting of raw bitumen and hydrotreated bitumen to form a blend possessing a relatively lower pour point.

Abstract: A delayed coking process and a solvent deasphalting process are combined so that an asphalt mix of asphalt and solvent from the solvent deasphalting process is sent as feedstock to the delayed coking process to form coke and intermediate hydrocarbon vapor and liquid products. The vaporization of the solvent in a delayed coker heater assists the flow of the asphalt mix through the heater, and a portion of the asphalt mix is directed to a delayed coking fractionator so that the flow of solvent through the delayed coking heater can be adjusted by varying the relative amounts of asphalt mix sent to the delayed coker heater and to the fractionator. A deasphalted oil mix of deasphalted oil and solvent from the solvent deasphalting process is heated by hotter fluid products from a fractionator in the delayed coking process, and makeup solvent to a solvent deasphalting section is heated by vapors in the fractionator overhead.

Abstract: Disclosed herein is an improved pitch for making readily stabilizable, substantially nonmesophasic carbon fibers. The pitch has a softening point of about 250.degree. C.(480.degree. F.) or above and is produced from an unoxidized thermal petroleum pitch by selectively reducing or eliminating a portion of the low molecular weight materials in a very short period of time so that the tendency to produce mesophase pitch is eliminated or reduced and so that the chemical integrity of the components of the higher molecular weight fractions is preserved as much as possible. Also disclosed is a method of producing carbon fibers therefrom and rovings or mats from such fibers.

Abstract: A pitch having optical anisotropy for use in production of carbon fibers, wherein the pitch is prepared using a compound represented by the formula (I) as a raw starting material and subjecting the compound to thermal modification and then removing light fractions ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.6, R.sub.7, R.sub.8, R.sub.9 and R.sub.10 each represents a hydrogen atom or a methyl group or an ethyl group; R.sub.5 represents a hydrogen atom or a methyl group; the total number of carbon atoms of R.sub.1, R.sub.2, R.sub.3 and R.sub.4 is from 2 to 4 and the total number of carbon atoms of R.sub.6, R.sub.7, R.sub.8 and R.sub.9 is from 2 to 4; and m is at least 3. The pitch is substantially homogeneous in quality, has a low softening point and has excellent molecular orientation.

Abstract: A novel coal tar based, low solids content, pitch is produced by oxidizing a selected coal tar distillation fraction with air to oxygen at elevated temperatures. This pitch is applicable to end use in which low solids content is desirable. Specifically it may be advantageously applied to the impregnation of carbon electrodes. The oxidized selected coal tar based low solids material described is characterized by high carbon yield and higher product density and has a higher in situ coking value and lower sulfur content which make it particularly beneficial when it is used as an impregnating pitch as compared to the currently commercially used petroleum based pitch.

Abstract: A continuous process for the production of carbonaceous pitch, including heat-treating an aromatic heavy oil in a first thermal cracking zone for obtaining a first cracked product, and introducing the first cracked product into a second thermal cracking zone where it is thermally cracked by direct contact with a gaseous heat transfer medium to form distillable cracked components and a mesophase-containing pitch. The liquid phase in the second thermal cracking zone, including the mesophase-containing pitch, is discharged therefrom and separated into a mesophase-rich pitch and a matrix pitch having a low concentration of mesophase. The mesophase-rich pitch is recovered while at least a portion of the matrix pitch is recycled to the second thermal cracking zone.

Abstract: A continuous process of producing carbonaceous pitch, including heat-treating an aromatic heavy oil for obtaining a first cracked product, and thermally cracking the first product in a cracking zone by direct contact with a gaseous heat transfer medium to obtain distillable cracked components and a mesophase-containing pitch. A first portion of the liquid phase in the cracking zone, including the mesophase-containing pitch, is separated into a mesophase-rich pitch and a matrix pitch having a low concentration of mesophase. The mesophase-rich pitch is recovered while at least a portion of the matrix pitch is recycled to the cracking zone. The distillable cracked components are withdrawn from the cracking zone and separated into light, middle and heavy fractions. At least a portion of the heavy fraction is heat treated and is recycled to the cracking zone.

Abstract: In a process for producing an optically anisotropic carbonaceous pitch having a low softening point for the production of carbon material starting oil to be used is a tar-like substance which is a mixture of compounds not substantially containing chloroform insolubles but containing components having a boiling point of 540.degree. C. or more as principal components and consisting principally of carbon and hydrogen. The tar-like substance has a content of n-heptane insolubles of up to 1 wt % and contains an aromatic oil fraction and a resin fraction as the principal components of n-heptane soluble components. The aromatic carbon fraction, fa, is at least 0.7, the number-average molecular weight is up to 1,000 and the maximum molecular weight is up to 2,000 for each of the aromatic oil and resin fractions.

Abstract: Method and device for manufacturing of asphalt bulk masses where a substantial part of the heat energy of the furnace gases from the drying and mixing process is transferred to the bulk mass fractions before those are supplied to the drying and mixing process and where the furnace gases by this process at the same time are cleaned for pollutions. Bulk masses are directed downwards between two parallelly arranged inclined planes (1, 5) where the lower inclined plane (1) comprising horizontally arranged downwards directed ribs (2) directing the furnace gases to the lower side of the bulk masses and where the second inclined plane (5) comprising vertically arranged ribs (4) suctioning the cleaned furnace gases up from the bulk masses after a substantial part of the heat energy being transferred to the bulk masses. At the lower and upper ends of the inclined planes accumulations of the bulk masses (7, 11) are maintained for preventing air from the atmosphere to penetrate into the system.

Abstract: Pitch free from quinoline insoluble components is prepared by heat-treating coal tar or coal tar pitch in the absence or in the presence of carbonaceous particles and centrifuging at a high temperature the reaction product resulting from the heat treatment or a mixture of the reaction product from the heat treatment and coal tar-type light or middle oil.

Abstract: Disclosed is a one-step method of producing an industrial asphalt from a bituminous material which comprises mixing together without air-blowing:(a) a feed material comprising a bituminous material having a viscosity of at least 50 centistokes at 350 degrees Fahrenheit and wherein the feed petroleum residuum forms a single phase when mixed with 5 percent ferric chloride; and(b) from about 0.1 to 20.0 percent by weight of ferric chloride, said mixing being done at a temperature in the range of 351 to 600 degrees Fahrenheit, whereby the softening point of the feed is substantially increased and the penetration is significantly decreased.

Abstract: A road asphalt composition having a penetration at 25.degree. C. in the range of 85 to 100 is made by blending together: (a) a pitch having an initial boiling point of at least 520.degree. C. obtained as a residue in the visbreaking of crude oil, and (b) a distillation residue having a penetration at 25.degree. C. in the range of 150 to 500 obtained in the distillation of crude oil.

Abstract: A mesophase pitch suitable for carbon products, particularly for carbon fibers, which has a mesophase content of at least 40%, preferably at least 60%, and a larger mesophase domain, is produced by adding at least one part by weight of at least one of an alcohol and a phenol to 100 parts by weight of heavy bitumens, subjecting the resulting mixture to pretreatment by heating at least at 250.degree. C., and then subjecting the pretreated mixture to heat treatment until mesophases are formed.

Abstract: Pitch for the production of carbon fibers which contains from 5 to 40% of the optically anisotropic region which is insoluble in organic solvents having a solubility parameter from 7.4 to 9.0 but is soluble in organic solvents having a solubility parameter from 9.2 to 11.0.

Abstract: .[.In a hydrogenation operation employing an ebullated catalytic bed, recycle is recovered from the hydrogenated product with at least 25%, by volume, of the recycle boiling above 950.degree. F. The recycle is cooled to a temperature of from 350.degree. to 600.degree. F. to separate coke precursors, prior to recycle to the hydrogenation. Higher conversion levels can be achieved by effecting recycle in such manner..]..Iadd.Disclosed is a hydrogenation process using at least one fluidized catalytic stage and a recycle material of heavy hydrogenated effluent. The heavy effluent material is cooled to a temperature within 350.degree.-600.degree. F. to separate toluene and heptane insoluble coke precursors prior to recycle. This separation may be enhanced by the use of centrifugation, filtration or a bed of particulate material (e.g. calcined coke). .Iaddend.