The disclosed methods for preparing and isolating carboxylic esters ensure a high product purity and minimize technical complexity. These methods are based on the reaction of a carboxylic acid with an alcohol in an aqueous medium. In some examples, the alcohol is used both for the esterification and for the precipitation of the salts, preferably ammonium salts, formed in the synthesis.

The disclosed methods for preparing and isolating carboxylic esters ensure a high product purity and minimize technical complexity. These methods are based on the reaction of a carboxylic acid with an alcohol in an aqueous medium. In some examples, the alcohol is used both for the esterification and for the precipitation of the salts, preferably ammonium salts, formed in the synthesis.

The present technology relates to the production and recovery of acetic acid. The recovery processes may include providing a first process stream including acetic acid and greater than 250 ppm of propionic acid; separating at least a portion of the propionic acid from the acetic acid within the first process stream to provide an acetic acid stream including acetic acid and less than 250 ppm of propionic acid and a bottoms stream including propionic acid and acetic acid; reacting the bottoms stream to form a product stream including components of respectively lower boiling points than corresponding components in the bottoms stream; and separating components of the product stream to form an overhead stream including one or more acetates and a bottoms stream including one or more propionates.

The present technology relates to the production and recovery of acetic acid. The recovery processes may include providing a first process stream including acetic acid and greater than 250 ppm of propionic acid; separating at least a portion of the propionic acid from the acetic acid within the first process stream to provide an acetic acid stream including acetic acid and less than 250 ppm of propionic acid and a bottoms stream including propionic acid and acetic acid; reacting the bottoms stream to form a product stream including components of respectively lower boiling points than corresponding components in the bottoms stream; and separating components of the product stream to form an overhead stream including one or more acetates and a bottoms stream including one or more propionates.

The present technology relates to the production and recovery of acetic acid. The recovery processes may include providing a first process stream including acetic acid and greater than 250 ppm of propionic acid; separating at least a portion of the propionic acid from the acetic acid within the first process stream to provide an acetic acid stream including acetic acid and less than 250 ppm of propionic acid and a bottoms stream including propionic acid and acetic acid; reacting the bottoms stream to form a product stream including components of respectively lower boiling points than corresponding components in the bottoms stream; and separating components of the product stream to form an overhead stream including one or more acetates and a bottoms stream including one or more propionates.

Disclosed herein are methods for forming ammonium salts of C4 diacids in a fermentation process with simultaneous removal of divalent metal carbonate salts. The pH of fermentation broths obtained during the production of fumaric, maleic, malic, and/or succinic acid by a microorganism is controlled by using alkaline oxygen containing calcium or magnesium compounds in the hydroxide, oxide, carbonate or bicarbonate formsforming divalent metal salts of the diacids that are partially or wholly insoluble in the broth. The calcium or magnesium salts of the diacids are substituted with ammonium by introduction of ammonium salts at elevated temperature and pressure dissolving precipitated divalent metal cation salts of the diacids and forming soluble ammonium salts thereof. Carbonate in the form of CO.sub.2 or bicarbonate is simultaneously added to the fermentation media at the elevated temperature and pressure. The temperature and pressure are then reduced forming insoluble divalent metal carbonate salts that are separated from the solubilized ammonium diacid salts. The recovered metal carbonate salts can be recycled as pH control materials in subsequent fermentation reactions. Also disclosed is use of the solubilized ammonium diacid salts directly as a reagent for hydrogenation to form the derivatives N-methyl-2-pyrrolidone (NMP) gamma-butyrolactone (GBL) and 1,4-butane-diol (BDO) in single pot reactions.

Disclosed herein are methods for forming ammonium salts of C4 diacids in a fermentation process with simultaneous removal of divalent metal carbonate salts. The pH of fermentation broths obtained during the production of fumaric, maleic, malic, and/or succinic acid by a microorganism is controlled by using alkaline oxygen containing calcium or magnesium compounds in the hydroxide, oxide, carbonate or bicarbonate formsforming divalent metal salts of the diacids that are partially or wholly insoluble in the broth. The calcium or magnesium salts of the diacids are substituted with ammonium by introduction of ammonium salts at elevated temperature and pressure dissolving precipitated divalent metal cation salts of the diacids and forming soluble ammonium salts thereof. Carbonate in the form of CO.sub.2 or bicarbonate is simultaneously added to the fermentation media at the elevated temperature and pressure. The temperature and pressure are then reduced forming insoluble divalent metal carbonate salts that are separated from the solubilized ammonium diacid salts. The recovered metal carbonate salts can be recycled as pH control materials in subsequent fermentation reactions. Also disclosed is use of the solubilized ammonium diacid salts directly as a reagent for hydrogenation to form the derivatives N-methyl-2-pyrrolidone (NMP) gamma-butyrolactone (GBL) and 1,4-butane-diol (BDO) in single pot reactions.

Provided herein is a process of ion exchange comprising malonic acid or a salt thereof and a cation or an anion cation exchange resin. The ion exchange is accomplished, e.g., and without limitation by continuous ion exchange. A valve and resin bed configuration is useful in this regard. The malonic acid separated by ion exchange is esterified, e.g., by Fisher esterification by using an acid and an alcohol.

Provided herein is a process of ion exchange comprising malonic acid or a salt thereof and a cation or an anion cation exchange resin. The ion exchange is accomplished, e.g., and without limitation by continuous ion exchange. A valve and resin bed configuration is useful in this regard. The malonic acid separated by ion exchange is esterified, e.g., by Fisher esterification by using an acid and an alcohol.

Methods for the preparation and isolation of malonic acid, a salt or a diesters thereof, preferably bio-based versions of the foregoing are provided.