Kobe Steel, Ltd.

Kabushiki Kaisha Kobe Seiko Sho

Takeharu Tanaka

Koji Yamamoto

Shingo Yoshida

Masahiro Motoyuki

Seiichi Yamamoto

Maki Hamaguchi

Yoshiyuki Nagase

Disclosed is a polyvinyl chloride recovering method for recovering polyvinyl chloride from waste including polyvinyl chloride by a continuous operation, and an system for carrying out the method, wherein the method comprises: an insoluble solid matter removing process of removing insoluble solid matters from a hot mixture of a solvent capable of dissolving polyvinyl chloride, and the waste; a solidifying process of solidifying polyvinyl chloride in water by bringing hot water into contact with a solution obtained by removing the insoluble solid matters from the hot mixture to remove the solvent; and a separating process of separating the solidified polyvinyl chloride from the water.

Method of recovering polyvinyl chloride and apparatus therefor

An object of the present invention is to provide a method for manufacturing 2,6-DMN, in which even when a mixture containing DMN isomers which includes 5 wt % or more of 2,7-DMN is used, a highly pure 2,6-DMN can be obtained. The method for manufacturing the highly pure 2,6-dimethylnaphthalene of the present invention comprises performing cooling crystallization of a mixture containing dimethylnaphthalenes which includes 2,6-dimethylnaphthalene, performing solid-liquid separation to obtain a solid component, and washing the solid component using a solvent, wherein the solid-liquid separation performed after the cooling crystallization includes press filtration. In the present invention, the pressure of the press filtration is preferably 10 kg/cmor more, and according to the method of the present invention, even when a DMN mixture containing 5 wt % or more of 2,7-DMN is used as a feedstock, a highly pure 2,6-DMN can be manufactured, and in addition, even when a DMN mixture containing less than 25 wt % of 2,6-DMN is processed by cooling crystallization, a highly pure 2,6-DMN can be manufactured.

Method for producing 2,6-dimethylnaphthalene

A method for purifying crude 2,6-naphthalenedicarboxylic acid includes a reduction step of reducing crude 2,6-naphthalenedicarboxylic acid containing 6-formyl-2-naphthoic acid with hydrogen and a cleaning step of cleaning the reduction product with alcohol. Preferably, in the reduction step, the crude 2,6-naphthalenedicarboxylic acid and the hydrogen is brought into contact with a hydrogenation catalyst in a liquid phase, and particularly in water. The method makes the purification process less complex and makes it possible to produce high-purity 2,6-naphthalenedicarboxylic acid without damaging equipment or increasing cost.

Method for purifying crude 2,6-naphthalenedicarboxylic acid

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Kobe, Japan

Takeharu Tanaka