Hyosung Corporation

Young-Gyo Choi

Ik-Hyun Kwon

Yang-Ho Chenon

Hyun-Soo Kim

Yang-Ho Cheon

Byoung-Whan Soh

Byung-Jun Song

Jong-Cheul Ji

Woo-Sung Kim

The present invention relates to a method for separating and refining high purity 2,6-naphthalene dicarboxylic acid having an excellent color and purity of 99.9% or more by using crude 2,6-naphthalene dicarboxylic acid. And more particularly, the present invention relates to a method for separating and refining 2,6-naphthalene dicarboxylic acid, in which adjustment of pressure and temperature during multiple-step crystallization process enables controlling nucleation and the crystal growth rate, thereby allowing a particle size distribution and form to be controlled.

Method and apparatus for separating and refining high purity 2,6-naphthalene dicarboxylic acid using crystallization

The present invention relates to a method for preparing 1,5-dimethyltetralin using a dealuminated zeolite beta catalyst. The preparation method of 1,5-dimethyltetralin according to the present invention has the effects of not only showing high conversion and high selectivity of 1,5-dimethyltetralin but also of suppressing deactivation of a zeolite beta catalyst so as to enhance the catalyst life, by using the dealuminated zeolite beta catalyst.

Preparation method of 1,5-dimethyltetralin using dealuminated zeolite beta catalyst

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.

Method for obtaining 2,6-dimethylnaphthalene using isomerization and crystallization processes

Disclosed herein is a process of producing high purity and high yield dimethylnaphthalene by dehydrogenating a dimethyltetralin isomer using a metal catalyst for dehydrogenation. The metal catalyst contains a carrier selected from alumina (AlO), silica (SiO), a silica-alumina mixture and zeolite. The metal catalyst also contains 0.05 to 2.5% by weight of platinum (Pt), 0.1 to 3.0% by weight of tin (Sn) or indium (In), 0.5 to 15.0% by weight of at least one selected from the group consisting of potassium (K), magnesium (Mg) and cesium (Cs), 0.3 to 3.0% by weight of chlorine, and 0.01 to 3.0 % by weight of zinc (Zn) or gallium (Ga) as active components based on an element weight of the final catalyst.

Dehydrogenation process of dimethylnaphthalene using metal catalyst

A method for separating and purifying 2,6-dimethylnaphthalene, is provided in which 2,6-dimethylnaphthalene of high purity is obtained from a mixture of dimethylnaphthalene isomers with a high yield, by means of a combined process of column melt crystallization and sweating operation.

Method for separating and purifying 2,6-dimethylnaphthalene

An apparatus and a method for effectively recovering acetic acid and catalyst from a mother liquor discharged from a series of processes including an oxidation process, a crystallization process and a solid-liquid separation process, in a continuous process for preparing naphthalenedicarboxylic acid by oxidizing dimethylnaphthalene in the presence of an oxygen-containing gas and an acetic acid solvent, using a catalyst system comprising a transition metal such as cobalt or manganese, and a bromine-based compound, are provided.

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Gyeonggi-do, South Korea

Young-Gyo Choi