Showa Denko K.k.

Takashige Miyanari

Hiroshi Uchida

Wataru Oguchi

Tomoyoshi Higashi

Etsuko Kadowaki

Masayuki Fujimoto

Hiroshi Nishino

Takaharu Sasaki

A process for producing an ester comprising reacting a carboxylic acid and ethylene in the presence of an acid catalyst in a vapor phase, wherein the concentration of olefin having 3 or more carbon atoms in the starting materials is controlled to 10,000 ppm or less in terms of the molar ratio to the total of the olefin and ethylene. The deterioration of the catalyst can be remarkably prevented from proceeding and a continuous and stable operation can be performed for a long time.

Process for producing esters

A process for purifying acetic acid which comprises: introducing a feedstock aqueous solution of acetic acid having an acetic acid concentration of from 10 to 50% by weight into an extractor; supplying an extracting medium containing isopropyl acetate in an amount from 0.6 to 3.0 times by weight the amount of the feedstock solution thereinto in such a manner that the extracting medium is made in contact with the feedstock solution; extracting acetic acid into the extracting medium; separating the extracting medium containing acetic acid from an extraction residue; supplying the extraction medium containing acetic acid into an azeotropic distillation column; distilling off the isopropyl acetate contained in the extraction medium from a top of the azeotropic distillation column via azeotropic distillation with water; condensing a distillate from the top of the azeotropic distillation column, to divide the distillate into a water-poor phase being rich in isopropyl acetate and a water-rich phase being rich in water; returning at least a portion of the water-poor phase into the extractor as the extracting medium; and recovering the acetic acid, which has been thus dehydrated and purified, from a bottom of the azeotropic distillation column.

Process for purifying acetic acid

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Oita, Japan

Takashige Miyanari