The present invention provides a method of producing/purifying highly unsaturated fatty acids and/or derivatives thereof while suppressing deterioration of a silver salt aqueous solution, in production/purification of highly unsaturated fatty acids and/or derivatives thereof using the aqueous solution of silver salt. The present invention also contacts or mixes a mixture having a peroxide value (POV) of 10 or smaller with an aqueous solution of silver salt, in a method of purifying highly unsaturated fatty acids and/or derivatives thereof from a mixture comprising highly unsaturated fatty acids and/or derivatives thereof.

A production method of highly unsaturated fatty acids with a high purity/high yield that compensates for shortcomings of conventional techniques is provided.

A purification method of highly unsaturated fatty acids and/or derivatives thereof comprising (a) contacting and stirring first raw materials comprising the substances with a first silver salt aqueous solution to collect a first oil layer and a first aqueous layer; (b) separating the first aqueous layer into a second silver salt aqueous solution and the substances; and (c) contacting and stirring the first oil layer with the second silver salt aqueous solution for separation into an oil layer and an aqueous layer to obtain a second aqueous layer comprising the substances.

A production method of highly unsaturated fatty acids with a high purity/high yield that compensates for shortcomings of conventional techniques is provided.

A purification method of highly unsaturated fatty acids and/or derivatives thereof comprising (a) contacting and stirring first raw materials comprising the substances with a first silver salt aqueous solution to collect a first oil layer and a first aqueous layer; (b) separating the first aqueous layer into a second silver salt aqueous solution and the substances; and (c) contacting and stirring the first oil layer with the second silver salt aqueous solution for separation into an oil layer and an aqueous layer to obtain a second aqueous layer comprising the substances.

Disclosed is a method for purifying an ester compound, including: adding a base to a resultant reaction mixture comprising a plasticizer of an ester compound synthesized by an esterification reaction of an acid and an alcohol so as to neutralize unreacted acids; applying steam to the resultant reaction mixture which has been neutralized; adding diatomite to the resultant reaction mixture which has been steamed, prior to filtration through a filter, and then subjecting the resultant reaction mixture to which the diatomite has been added to a primary filtration; and adding an activated white clay to the resultant reaction mixture, and then subjecting the resultant reaction mixture which has been primarily filtrated to a secondary filtration through a filter.

Disclosed is a method for purifying an ester compound, including: adding a base to a resultant reaction mixture comprising a plasticizer of an ester compound synthesized by an esterification reaction of an acid and an alcohol so as to neutralize unreacted acids; applying steam to the resultant reaction mixture which has been neutralized; adding diatomite to the resultant reaction mixture which has been steamed, prior to filtration through a filter, and then subjecting the resultant reaction mixture to which the diatomite has been added to a primary filtration; and adding an activated white clay to the resultant reaction mixture, and then subjecting the resultant reaction mixture which has been primarily filtrated to a secondary filtration through a filter.

Disclosed is a method of purifying terephthalate-based ester compounds, including: adding a base to a resultant reaction mixture comprising terephthalate-based ester compounds synthesized by esterification of terephthalic acid and alcohol so as to neutralize unreacted acids; applying steam to the resultant reaction mixture which has been neutralized; adding a filter aid to the resultant reaction mixture which has been steamed prior to filtration through a filter; and filtering through a filter the resultant reaction mixture to which the filter aid has been added, wherein the filter aid comprises diatomite particles having an average particle size of 50 m to 90 m.

Disclosed is a method of purifying terephthalate-based ester compounds, including: adding a base to a resultant reaction mixture comprising terephthalate-based ester compounds synthesized by esterification of terephthalic acid and alcohol so as to neutralize unreacted acids; applying steam to the resultant reaction mixture which has been neutralized; adding a filter aid to the resultant reaction mixture which has been steamed prior to filtration through a filter; and filtering through a filter the resultant reaction mixture to which the filter aid has been added, wherein the filter aid comprises diatomite particles having an average particle size of 50 m to 90 m.

A process for the production of butyl acrylate by direct esterification of acrylic acid with butanol, the reaction being catalyzed by sulfuric acid. More specifically, the present invention relates to an improved process for producing butyl acrylate comprising a step of upgrading the heavy by-products generated during this production, leading to a high productivity of a product meeting the standards as regards purity and acidity, under optimized energy conditions.

A process for the production of butyl acrylate by direct esterification of acrylic acid with butanol, the reaction being catalyzed by sulfuric acid. More specifically, the present invention relates to an improved process for producing butyl acrylate comprising a step of upgrading the heavy by-products generated during this production, leading to a high productivity of a product meeting the standards as regards purity and acidity, under optimized energy conditions.

The invention relates to a method for separating a mixture containing at least one carboxylic acid vinyl ester of general formula RC(O)OCHCH.sub.2 and at least one carboxylic acid of general formula RCOOH, wherein R in either case can be an aliphatic group having 12 to 22 C atoms or a cycloaliphatic group having 12 to 22 C atoms, or an aromatic group having 12 to 22 C atoms, and R can be identical or different, characterized in that the carboxylic acid is converted to its anhydride RC(O)OC(O)R and the carboxylic acid vinyl ester is subsequently separated.