Abstract: Disclosed is a method for separating aromatic compounds using a simulated moving bed adsorptive chromatography and a crystallization process, comprising a sulfolan process that is a non-aromatic compound removing process, a benzene/toluene fractionation process, an aromatic compound fractionation process, a selective toluene disproportionation process, a transalkylation process, a crystallization process for para-xylene separation, a simulated moving bed para-xylene separation process and a xylene isomerization process, wherein the method is characterized by further comprising a simulated moving bed xylene mixture pre-treatment process and an additional xylene isomerization process. The separation method of aromatic compounds according to the present invention can make significant improvement in para-xylene and benzene production in the overall process, as compared to the conventional aromatic compound separation process.

Abstract: High-purity 2,6-dimethylnaphthalene is prepared by (1) subjecting a dimethylnaphthalene isomer mixture rich in 1,5-dimethylnaphthalene, high boiling point materials, unreacted 1,5-dimethyltetralin, and low boiling point materials, which are produced from a dehydrogenation reaction of 1,5-dimethyltetralin, to separation, using a distillation column; subjecting the dimethylnaphthalene mixture separated by the distillation column to liquid state isomerization in the presence of an isomerization catalyst; (3) a first crystallization (melt crystallization process) by cooling the product of liquid state isomerization with a refrigerant without a solvent to form crystals; and (4) a second crystallization (solution crystallization process) of mixing the crystals of the first crystallization step with a solvent to form crystals.

Abstract: A pressure swing adsorption process to separate para-xylene and ethylbenzene from C8 aromatics which uses a para-selective, non-acidic, medium pore molecular sieve of the MFI structure type and is operated isothermally in the vapor phase at elevated temperatures and pressures is integrated with crystallization to produce para-xylene product. A fixed bed of adsorbent is saturated with pX and EB, which are preferentially adsorbed, the feed is stopped, and lowering the partial pressure desorbs the pX and EB. The process effluent, which is rich in pX and EB, is crystallized to obtain para-xylene product.

Abstract: A process for production of paraxylene from a charge containing C7-C9 aromatic hydrocarbons in which a first fraction is enriched to at least 30% weight with paraxylene and this fraction is purified by at least one high-temperature crystallization in at least one crystallization zone. Said first fraction is crystallized in a crystallization zone at high temperature T1 and advantageously between +10 and −25° C., crystals in suspension in a mother liquor are recovered, the crystals are separated from the mother liquor in at least a first separation zone, the crystals obtained are partially melted in at least a zone for partial melting and a suspension of crystals is recovered, the crystals in suspension are separated and washed in at least one separation and washing zone and pure paraxylene crystals and washing liquor are recovered, and pure crystals are optionally completely melted and a liquid stream of melted paraxylene is collected.

Abstract: A continuous process for integrated processing of a C8+ aromatic hydrocarbon stream is disclosed for recovery of a high purity meta-xylene product in conjunction with efficient separation and recovery of purified para-xylene and, optionally, purified ortho-xylene products.

Abstract: Herein is disclosed a method of crystallization with the particle size distribution being controlled, characterized in that while crystals are being precipitated by vacuum concentration crystallization, the temperature of the slurry is periodically varied up and down during the concentration of the crystallization mother liquor (i.e., the slurry), which method is an excellent one free from the defects of the conventional methods.

Abstract: A process for producing paraxylene of very high purity from a charge containing a mixture of aromatic hydrocarbons having 7 to 9 carbon atoms in which at least a portion of the charge is made to circulate in a zone suited to enrich a first fraction of paraxylene and at least a portion of said first fraction is purified by at least one high-temperature crystallization in at least one crystallization zone, the process being characterized in that said first paraxylene-enriched fraction is crystallized in a crystallization zone comprising at least two crystallization stages (50,70) at high temperature, and advantageously between +10 and -25 .degree. C.The paraxylene enriching zone can be a crystallization at very low temperature, a selective adsorption or a toluene disproportionation zone.

Abstract: A process for production of paraxylene from a charge containing C7-C9 aromatic hydrocarbons in which a first fraction is enriched to at least 30% weight with paraxylene and this fraction is purified by at least one high-temperature crystallization in at least one crystallization zone. Said first fraction is crystallized in a crystallization zone at high temperature T1 and advantageously between +10 and -25.degree. C., crystals in suspension in a mother liquor are recovered, the crystals are separated from the mother liquor in at least a first separation zone, the crystals obtained are partially melted in at least a zone for partial melting and a suspension of crystals is recovered, the crystals in suspension are separated and washed in at least one separation and washing zone and pure paraxylene crystals and washing liquor are recovered, and pure crystals are optionally completely melted and a liquid stream of melted paraxylene is collected.

Abstract: A process for producing highly pure 2,6-dimethylnaphthalene in a high yield from a mixture of dimethylnaphthalene isomers in the presence of a solvent, such as an aliphatic or alicyclic saturated hydrocarbon. Highly pure 2,6-dimethylnaphthalene can be produced steadily for a long time by filtering the 2,6-dimethylnaphthalene crystal precipitated by the crystallizing by using a filtration apparatus, such as a rotary vacuum filter, peeling-off the filtered cake from a filter cloth and cleaning the filter cloth with a solvent, at a temperature not lower than a filtration temperature.

Abstract: Improved process and apparatus for purifying paraxylene from mixed C8-aromatic feedstocks are disclosed in which the use of at least two crystallization stages operated at different temperatures in combination with a final product separator improves purity and recovery while reducing capital and energy costs.

Abstract: After being subjected to a melt crystallization operation, a crystal-containing melt is formed into particles of the same size and shape and then conducted in counter-flow relationship to washing liquid in a washing column. The crystal-containing melt can be formed into particles by a device which deposits the crystal-containing melt as identically sized drops onto a cooling belt. The particles can be completely hardened or only partially hardened when entering the washing column.

Abstract: The present invention relates to a process for the production of collagen foams in the form of continuous tapes, characterized in thata) solved or dispersed collagen is cast into disk molds,b) the collagen solution or dispersion is frozen in the disk mold and subsequently is freeze-driedc) continuous tapes are produced from the freeze-dried disks by mechanical processes. Furthermore, the present invention relates to the use of said tapes so obtained in medicine, cosmetic and hygiene.

Abstract: A process for purifying 1,1,3,4,4,6-hexamethyltetralin is disclosed comprising melting crude 1,1,3,4,4,6-hexamethyltetralin in methanol with heating, cooling the resulting suspension, and adding seed crystals at a temperature of 45.degree.-60.degree. C.; as well as a process for purifying 1,1,3,4,4,6-hexamethyltetralin comprising recrystallizing crude 1,1,3,4,4,6-hexamethyltetralin from a mixed solvent of methanol and a solvent capable of easily dissolving 1,1,3,4,4,6-hexamethyltetralin, the proportion of this solvent being 10 to 25% by weight based on the weight of methanol. These processes make it possible to obtain 1,1,3,4,4,6-hexamethyltetralin of high purity easily with high recovery by purifying crude 1,1,3,4,4,6-hexamethyltetralin.

Abstract: In a process for selective crystallization of 2,6-dialkyl-naphthalene selected from the group consisting of methyl-n-propyl-naphthalene, methyl isopropyl-naphthalene, ethyl-isopropyl-napthalene, ethyl-n-butyl-naphthalene, di-n-propyl-naphthalene, diisopropyl-naphthalene, methyl-amyl-naphthalene, ethyl-amyl-naphthalene, propyl-amyl-naphthalene, di-n-butyl-naphthalene and diisobutyl-naphthalene from their isomer mixtures from a polar solvent solution, the improvement comprising effecting the crystallization with constant stirring at a temperature from 25.degree. to -30.degree. C. to obtain the 2,6-dialkyl-naphthalene at least 95% pure.