Process for the preparation of purified dicarboxylic acids
AssigneeNovamont S.p.A.
InventorsLuigi Capuzzi, Francesca Digioia
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Abstract
This invention relates to a process for the purification of dicarboxylic acids obtained from the hydrolysis of carboxylic acid triglycerides having more than one acid functional group. The process comprises in particular the separation of at least some of the glycerine from the hydrolysis product in an aqueous phase, evaporating and/or distilling the resultant organic phase and recovering at least some of the evaporated and/or distilled dicarboxylic acids through at least one crystallisation operation.
Claims20
A process for the preparation of purified dicarboxylic acids from a mixture containing triglycerides of carboxylic acids having more than one acid functional group comprising the steps of:
- a) hydrolysing said mixture containing triglycerides in the presence of water, obtaining a reaction product comprising dicarboxylic acids and glycerine;
- b) separating out an aqueous phase comprising at least a part of the glycerine from the remaining reaction product from step a) organic phase;
- c) evaporating and/or distilling the organic phase obtained from step b), separating out a residue;
- and
- d) recovering at least a part of the dicarboxylic acids from the organic phase evaporated and/or distilled in step c) by means of at least one crystallisation operation, said step comprising the operations of:
- d1) extracting the organic phase evaporated and/or distilled in step c) with water in the presence of an organic solvent, obtaining an aqueous phase containing said dicarboxylic acids
- d2) crystallising out said dicarboxylic acids from said aqueous phase obtained in step d1), wherein said step d1) comprises at least one counter-current extraction operation.
A process for the preparation of purified dicarboxylic acids from a mixture containing triglycerides of carboxylic acids having more than one acid functional group comprising the steps of:
- a) hydrolysing said mixture containing triglycerides in the presence of water, obtaining a reaction product comprising dicarboxylic acids and glycerine;
- b) separating out an aqueous phase comprising at least a part of the glycerine from the remaining reaction product from step a) organic phase;
- c) evaporating and/or distilling the organic phase obtained from step b), separating out a residue;
- and
- d) recovering at least a part of the dicarboxylic acids from the organic phase evaporated and/or distilled in step c) by means of at least one crystallisation operation, said step comprising at least one melt crystallisation of said dicarboxylic acids.
A process for the preparation of purified dicarboxylic acids from a mixture containing triglycerides of carboxylic acids having more than one acid functional group comprising the steps of:
- a) hydrolysing said mixture containing triglycerides in the presence of water, obtaining a reaction product comprising dicarboxylic acids and glycerine;
- b) separating out an aqueous phase comprising at least a part of the glycerine from the remaining reaction product from step a) organic phase;
- c) evaporating and/or distilling the organic phase obtained from step b), separating out a residue;
- and
- d) recovering at least a part of the dicarboxylic acids from the organic phase evaporated and/or distilled in step c) by means of at least one crystallisation operation, wherein the triglycerides of carboxylic acids mainly comprise azelaic acid and higher dicarboxylic acids and said recovery step d) comprises at least one crystallisation of said dicarboxylic acids from an organic solvent selected from aliphatic hydrocarbons.
Dependencies are inferred from the claim text.