Showa Denko K.k.

Showa Denko Kabushiki Kaisha

Masayuki Fujimoto

Hiroshi Uchida

Tsuneo Tajima

Takashige Miyanari

Kazuhiko Ohga

Hiroshi Nishino

Shigeru Hatanaka

Takaharu Sasaki

Provided is a method for producing n-propyl acetate capable of suppressing the deterioration of a hydrogenation catalyst to such an extent that the catalyst can be industrially used, for example, in the case where n-propyl acetate is produced by performing a hydrogenation reaction in the presence of the hydrogenation catalyst using, as a raw material liquid, a liquid containing allyl acetate or the like which has been produced from propylene, oxygen and acetic acid and obtained using a purification process such as distillation. In such a method for producing n-propyl acetate, the concentration of a formyl group-containing compound (such as acrolein, propionaldehyde or 2-methylcrotonaldehyde) and the concentration of an acryloyloxy group-containing compound (such as acrylic acid or allyl acrylate) in the raw material liquid are respectively set to 100 ppm by mass or less. As a result, the deterioration of the hydrogenation catalyst can be suppressed to such an extent that the catalyst can be industrially used.

Method for producing n-propyl acetate

A process for producing a hydrogenated ester by hydrogenating an unsaturated group-containing ester having a specific structure by using a hydrogenating catalyst so as to obtain a hydrogenated ester with a high selectivity. It is preferred that the unsaturated group-containing ester as the raw material is diluted with an inert solvent and/or the concentration of carboxylic acid contained in the raw material is made 1 wt. % or less so as to effect a hydrogenation reaction. The hydrogenating catalyst to be used for the above hydrogenation may preferably be one comprising at least one metal selected from Group 8 elements, Group 9 elements, and Group 10 elements in the periodic table according to, 1989,, and preferably has an acidity of 1.0&#xd7;10mmol/g or less.

Process for producing hydrogenated ester, hydrogenating catalyst used therefor and process for producing the catalyst

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

Masayuki Fujimoto