Abstract: The present invention relates to a novel method for preparing a catalyst of the formula (1), WOx wherein, W represents tungsten atom, O represents oxygen atom x represents a value determined by oxidative state of W, for partial oxidation of methylbenzenes, the method comprising: (a) a step of preparing tungsten oxide slurry by wet milling; (b) a step of supporting the slurry obtained in the step (a) on fire-resistance inorganic carrier by impregnation; (c) a step of drying the catalyst obtained in the step (b); and (d) a step of calcining the dried catalyst obtained in the step (c), and can reduce the reaction temperature on the basis of equivalent yield in the preparation of corresponding aromatic aldehyde from methylbenzenes since the catalyst has increased the surface areas compared to the conventional one, and thus has high conversion rate.

Abstract: The present invention relates to a method and an apparatus for continuously separating aromatic dialdehyde from a reaction mixture obtained by gas-phase oxidation of dimethylbenzene. The method for continuously separating aromatic dialdehyde includes the steps of congealing aromatic dialdehyde by cooling the gas-phase reaction mixture including the aromatic dialdehyde, which is obtained by gas-phase oxidation of dimethylbenzene, to 5-70° C. and separating the congealed aromatic dialdehyde from the remaining reaction mixture. Using the method and apparatus in accordance with the present invention, aromatic dialdehyde can be effectively and selectively separated from a reaction mixture obtained by gas-phase oxidation of dimethylbenzene in high yield.

Abstract: A catalyst for gas phase oxidation of methylbenzenes in the presence of molecular oxygen to produce corresponding aromatic aldehydes, a method for preparing the catalyst, and a method for producing aromatic aldehydes from methylbenzenes by using the catalyst. The catalyst comprises a compound represented by the following formula (1): WaXbYcOx ??(1) wherein W represents a tungsten atom, X represents one or more alkali metals selected from the group consisting of Li, Na, K, Rb, and Cs, Y represents one or more elements selected from the group consisting of Fe, Co, Ni, Cu, Mn, Re, Cr, V, Nb, Ti, Zr, Zn, Cd, Y, La, Ce, B, Al, Sn, Mg, Ca, Sr, and Ba, O stands for an oxygen atom, and the ratio of a:b:c is 12:0.001˜1:0˜5.

Abstract: The present invention relates to a method for preparing an aromatic dialdehyde, comprising, a) a step of gas phase oxidation reaction for preparing aromatic dialdehyde from dimethyl benzene; b) a step of separation for selectively recovering crude aromatic dialdehyde of molten phase from the reaction product of the step (a); and c) a step of purification for obtaining highly pure aromatic dialdehyde by purifying said crude aromatic dialdehyde, and a manufacturing system used for the preparation method. The method for preparation of the aromatic dialdehyde according to the present invention is simple, effective, and advantageous in that highly pure aromatic dialdehyde can be continuously prepared.

Abstract: The present invention relates to a method and an apparatus for continuously separating aromatic dialdehyde from a reaction mixture obtained by gas-phase oxidation of dimethylbenzene. The method for continuously separating aromatic dialdehyde includes the steps of congealing aromatic dialdehyde by cooling the gas-phase reaction mixture including the aromatic dialdehyde, which is obtained by gas-phase oxidation of dimethylbenzene, to 5-70° C. and separating the congealed aromatic dialdehyde from the remaining reaction mixture. Using the method and apparatus in accordance with the present invention, aromatic dialdehyde can be effectively and selectively separated from a reaction mixture obtained by gas-phase oxidation of dimethylbenzene in high yield.

Abstract: A catalyst for gas phase oxidation of methylbenzenes in the presence of molecular oxygen to produce corresponding aromatic aldehydes, a method for preparing the catalyst, and a method for producing aromatic aldehydes from methylbenzenes by using the catalyst. The catalyst comprises a compound represented by the following formula (1): WaXbYcOx ??(1) wherein W represents a tungsten atom, X represents one or more alkali metals selected from the group consisting of Li, Na, K, Rb, and Cs, Y represents one or more elements selected from the group consisting of Fe, Co, Ni, Cu, Mn, Re, Cr, V, Nb, Ti, Zr, Zn, Cd, Y, La, Ce, B, Al, Sn, Mg, Ca, Sr, and Ba, O stands for an oxygen atom, and the ratio of a:b:c is 12:0.001˜1:0˜5.

Abstract: The present invention relates to a hydrocarbon cracking catalyst in which zeolite is fixed in the pores of metal oxide and a method for preparing the same. The method of the invention comprises the steps of a) vacuumi zing a container including metal oxide; b) adding zeolite powder in water and stirring it to obtain a slurry solution; c) spraying the slurry solution of step (b) into the vacuous container to penetrate it into the pores of the metal oxide support; and d) drying the catalyst prepared, in step (c) and calcining it to fix zeolite powder in the metal oxide support. The hydrocarbon cracking catalyst of the present invention can improve production yield of such olefins as ethylene and propylene and such aromatic compounds as BTX, reduce pressure drop inside the reactor without forming the zeolite catalyst and has superior rigidity.

Abstract: The present invention relates to a method for preparing high-purity terephthalaldehyde from terephthalaldehyde crystal containing impurities by recrystallization using an antisolvent. Low-purity terephthalaldehyde prepared by a conventional method, which contains a small amount of impurities, is dissolved in a solvent and recrystallized using water as antisolvent to obtain high-purity terephthalaldehyde. The invention is significantly advantageous in using water only as antisolvent. Also, the purification process takes short time and is economical and environment-friendly.

Abstract: The present invention provides a pyrolysis tube for enhancing the yield of olefins and reducing a coking tendency in steam cracking of hydrocarbons. According to the present invention, the pyrolysis tube is characterized in that a plurality of mixing blades made by twisting two ends of a plate in opposite directions are included therein. The yield of ethylene is thereby improved and the coking tendency is reduced by mixing a fluid flow, improving a heat transfer rate and shortening a residence time of the reactants therein.

Abstract: The present invention relates to a method and an apparatus for continuously separating aromatic dialdehyde from a reaction mixture obtained by gas-phase oxidation of dimethylbenzene. The method for continuously separating aromatic dialdehyde includes the steps of congealing aromatic dialdehyde by cooling the gas-phase reaction mixture including the aromatic dialdehyde, which is obtained by gas-phase oxidation of dimethylbenzene, to 5-70° C. and separating the congealed aromatic dialdehyde from the remaining reaction mixture. Using the method and apparatus in accordance with the present invention, aromatic dialdehyde can be effectively and selectively separated from a reaction mixture obtained by gas-phase oxidation of dimethylbenzene in high yield.

Abstract: The present invention relates to a method for preparing high-purity terephthalaldehyde from terephthalaldehyde crystal containing impurities by recrystallization using an antisolvent. Low-purity terephthalaldehyde prepared by a conventional method, which contains a small amount of impurities, is dissolved in a solvent and recrystallized using water as antisolvent to obtain high-purity terephthalaldehyde. The invention is significantly advantageous in using water only as antisolvent. Also, the purification process takes short time and is economical and environment-friendly.

Abstract: The present invention relates to a process for pyrolysis of hydrocarbons for olefin preparation, and particularly to a process for pyrolysis of hydrocarbons comprising pyrolyzing paraffin hydrocarbons in the presence of steam to prepare olefins, where the pyrolysis is conducted in a pyrolysis reaction tube in which a porous inorganic substance with a pore diameter of 1 ?m˜5 mm, a porosity of 10˜80%, and a maximum specific surface area of 0.1 m2/g is inserted or filled. According to the present invention, in the hydrocarbon pyrolysis process, the porous inorganic substance is inserted or filled into the pyrolysis reaction tube, and thus the olefin yield can be improved compared to the conventional pyrolysis processes, a continuous operation period can be prolonged, and a life cycle of the pyrolysis reaction tube can be prolonged.

Abstract: Provided is a catalyst for partial oxidation of methylbenzenes comprising the compound represented by the following formula 1 and, optionally, a fire-resistant inorganic support: WOx??(1) where W stands for a tungsten atom, O stands for an oxygen atom and x is a number determined by the oxidation state of W. Also provided is a method for producing aromatic aldehydes from partial oxidation of methylbenzenes in gas phase using molecular oxygen using the afore-mentioned catalyst. The catalyst of the present invention can be prepared easily compared with conventional multi-component oxide catalysts. And, aromatic aldehydes can be produced from methylbenzenes with high selectivity and yield.

Abstract: The present invention relates to a catalyst for steam cracking of hydrocarbons, which steam cracks hydrocarbons to improve a yield of olefins such as ethylene and propylene, reduces produced coke, and has superior thermal stability at a high temperature. Particularly, the present invention provides a catalyst for steam cracking of hydrocarbons comprising potassium phosphate as a catalyst component, preparation thereof, and olefin preparation by steam cracking of hydrocarbons using the same.

Abstract: The present invention relates to a catalyst for steam cracking of hydrocarbons, which steam cracks hydrocarbons to improve a yield of olefins such as ethylene and propylene, reduces produced coke, and has superior thermal stability at a high temperature. Particularly, the present invention provides a catalyst for steam cracking of hydrocarbons comprising potassium phosphate as a catalyst component, preparation thereof, and olefin preparation by steam cracking of hydrocarbons using the same.

Abstract: The present invention relates to a process for pyrolysis of hydrocarbons for olefin preparation, and particularly to a process for pyrolysis of hydrocarbons comprising pyrolyzing paraffin hydrocarbons in the presence of steam to prepare olefins, where the pyrolysis is conducted in a pyrolysis reaction tube in which a porous inorganic substance with a pore diameter of 1 &mgr;m˜5 mm, a porosity of 10˜80%, and a maximum specific surface area of 0.1 m2/g is inserted or filled.

Abstract: The present invention provides a pyrolysis tube for enhancing the yield of olefins and reducing a coking tendency in steam cracking of hydrocarbons. According to the present invention, the pyrolysis tube is characterized in that a plurality of mixing blades made by twisting two ends of a plate in opposite directions are included therein. The yield of ethylene is thereby improved and the coking tendency is reduced by mixing a fluid flow, improving a heat transfer rate and shortening a residence time of the reactants therein.

Abstract: An improved production method of aromatic carboxylic acid products of significantly improved yield and quality by oxidizing alkyl aromatic substrates or their partially oxidized intermediates in a conventional MC-type catalyst system modified to contain additional components such as alkali metal or alkaline earth metal in an acetic acid medium in a feed gas containing oxygen and optionally carbon dioxide. Since carbon dioxide functioned as a co-oxidant along with oxygen in the oxidation reaction, the oxidation reaction proceeds more selectively to produce the carboxylic acid product much faster under milder reaction conditions over the conventional MC-type oxidation. In particular, the oxidation of para-xylene carried out by the novel present method enabled production of terephthalic acid of higher yield and enhanced quality, which were improved far more than the extent that generally could be expected by current PTA producers.