There is disclosed a process for the separation of long chain amino acid and long chain dibasic acid, comprising: (1) cooling the hydrolysis solution to crystallize and separate alkali salt of long chain dibasic acid to provide an aqueous solvent solution; (2) distilling the aqueous solvent solution of step (1) to recover the solvent and to recover alkylamine; (3) cooling the residual solution of step (2) to precipitate and separate alkali salt of long chain amino acid to provide a mother liquor; (4) adding an acid to the mother liquor of step (3) to yield alkanoic acid; (5) adding an acid to an aqueous solution of the alkali salt of long chain dibasic acid of step (1) to obtain long chain dibasic acid; and (6) neutralizing the alkali salt of long chain amino acid of step (3) with an acid to obtain long chain amino acid.

There is disclosed a process for the separation of long chain amino acid and long chain dibasic acid, comprising: (1) cooling the hydrolysis solution to crystallize and separate alkali salt of long chain dibasic acid to provide an aqueous solvent solution; (2) distilling the aqueous solvent solution of step (1) to recover the solvent and to recover alkylamine; (3) cooling the residual solution of step (2) to precipitate and separate alkali salt of long chain amino acid to provide a mother liquor; (4) adding an acid to the mother liquor of step (3) to yield alkanoic acid; (5) adding an acid to an aqueous solution of the alkali salt of long chain dibasic acid of step (1) to obtain long chain dibasic acid; and (6) neutralizing the alkali salt of long chain amino acid of step (3) with an acid to obtain long chain amino acid.

There is disclosed a process for the separation of long chain dibasic acid and fatty acid, comprising: (1) reacting a mixture of long chain dibasic acid and fatty acid with ammonium hydroxide to form an insoluble ammonium salt of fatty acid and a soluble ammonium salt of long chain dibasic acid; (2) recovering the insoluble ammonium salt of fatty acid; and (3) adding an acid to the mother liquor of step (2) to obtain the long chain dibasic acid.

There is disclosed a process for the separation of long chain dibasic acid and fatty acid, comprising: (1) reacting a mixture of long chain dibasic acid and fatty acid with ammonium hydroxide to form an insoluble ammonium salt of fatty acid and a soluble ammonium salt of long chain dibasic acid; (2) recovering the insoluble ammonium salt of fatty acid; and (3) adding an acid to the mother liquor of step (2) to obtain the long chain dibasic acid.

There is disclosed a process for the separation of long chain dibasic acid and fatty acid, comprising: (1) reacting a mixture of long chain dibasic acid and fatty acid with ammonium hydroxide to form an insoluble ammonium salt of fatty acid and a soluble ammonium salt of long chain dibasic acid; (2) recovering the insoluble ammonium salt of fatty acid; and (3) adding an acid to the mother liquor of step (2) to obtain the long chain dibasic acid.

The present invention relates to a method of recovering (meth)acrylic acid and an apparatus used for the recovery method. The recovery method according to the present invention discharges each (meth)acrylic acid aqueous solution of different concentrations at a (meth)acrylic acid absorption tower, and uses an extraction solvent of a specific ratio in the step of extracting (meth)acrylic acid, thus enabling the operation of a continuous process of recovering (meth)acrylic acid that can secure a high (meth)acrylic acid recovery rate, and can simultaneously significantly reduce purification energy cost.

The present invention relates to a method of recovering (meth)acrylic acid and an apparatus used for the recovery method. The recovery method according to the present invention discharges each (meth)acrylic acid aqueous solution of different concentrations at a (meth)acrylic acid absorption tower, and uses an extraction solvent of a specific ratio in the step of extracting (meth)acrylic acid, thus enabling the operation of a continuous process of recovering (meth)acrylic acid that can secure a high (meth)acrylic acid recovery rate, and can simultaneously significantly reduce purification energy cost.

The present invention relates to a method of recovering (meth)acrylic acid and an apparatus used for the recovery method. The recovery method according to the present invention discharges each (meth)acrylic acid aqueous solution of different concentrations at a (meth)acrylic acid absorption tower, and uses an extraction solvent of a specific ratio in the step of extracting (meth)acrylic acid, thus enabling the operation of a continuous process of recovering (meth)acrylic acid that can secure a high (meth)acrylic acid recovery rate, and can simultaneously significantly reduce purification energy cost.

A process for the recovery of polymer-grade (meth)acrylic acid, in the absence of organic solvent, from a gaseous reaction mixture comprising (meth)acrylic acid obtained by gas-phase oxidation of a precursor of the (meth)acrylic acid, the process carried out in a plant comprising at least one dehydration column and one finishing column, being characterized by the presence of at least one chemical treatment agent targeted at reducing the content of residual aldehydes. (Meth)acrylic acid obtained according to the invention meets criteria of high quality allowing it to be used in the manufacture of acrylic polymers, in particular for superabsorbents. This grade is also known as glacial acrylic acid GAA.

A process for the recovery of polymer-grade (meth)acrylic acid, in the absence of organic solvent, from a gaseous reaction mixture comprising (meth)acrylic acid obtained by gas-phase oxidation of a precursor of the (meth)acrylic acid, the process carried out in a plant comprising at least one dehydration column and one finishing column, being characterized by the presence of at least one chemical treatment agent targeted at reducing the content of residual aldehydes. (Meth)acrylic acid obtained according to the invention meets criteria of high quality allowing it to be used in the manufacture of acrylic polymers, in particular for superabsorbents. This grade is also known as glacial acrylic acid GAA.