E.O. Lawrence Berkeley National Laboratory

APPLICATION OF TECHNOLOGY: Carboxylic acids are important chemicals of commerce. They are among the most attractive products for manufacture from biomass, such as corn starch fermentation. Carboxylic acids are also stable oxidation products and therefore frequently appear as by-products or in aqueous waste streams. Carboxylic acids have many commercial applications such as:

• Raw material for manufacturing nylon and biodegradable plastics
• Builders in detergents
• Acidulents and buffers in food
• Chemical intermediates for the pharmaceutical industry

ADVANTAGES:

• Recovers low-volatility and low- to moderate-solubility carboxylic acids, such as adipic and succinic acids.
• Works simply, inexpensively, and with low energy consumption.
• Removes co-extracted water by stripping.
• Lessens the solubilities of carboxylic acids, allowing precipitation and recovery of most of the dissolved acid.
• Successful with commonly used solvents, such as ketones, esters, alcohols, and ethers.
• Recovers carboxylic acids from fermentation broths and other industrial streams.
• Effectively removes and recovers carboxylic acids from effluent streams.

ABSTRACT:

• A new technique for the recovery of carboxylic acids from solution in organic solvents has been developed by scientists at Berkeley National Laboratory. The approach is easy to execute and consumes less energy than current recovery methods. It is particularly well suited for low- to moderate-solubility carboxylic acids, such as adipic, succinic and fumaric acids. The invention also enhances the recovery of carboxylic acids from aqueous solutions, such as fermentation broths. Berkeley National Laboratory's new technique offers a definite economic advantage over present recovery methods: it saves energy and reduces waste products.

  REFERENCE NUMBER: IB-800

• C. Judson King III and John Starr's invention uses solvent extraction to remove carboxylic acid from aqueous solution. The addition of an organic solvent allows carboxylic acid and a small amount of water to co-extract from the aqueous phase into the solvent. Water, having a high volatility in organic media, is then easily stripped, distilled, or otherwise removed from the solvent extract. The removal of the co-extracted water lowers the solubility of the carboxylic acid, causing it to precipitate in product form. Once the water and precipitated carboxylic acid are removed, the remaining solvent is ready to recycle and recover more carboxylic acid from aqueous solution. Berkeley National Laboratory's invention is energy-efficient. It removes the small amount of co-extracted water without substantially evaporating the solvent phase.

  REFERENCE NUMBER: IB-841, 851

• Another process uses solvent extraction and is particularly well-suited for recovery of low- to moderate-solubility carboxylic acids from dilute and complex aqueous mixtures, such as waste streams and some fermentation brothes. The addition of an organic solvent allows the carboxylic acid and a small amount of water to co-extract from the aqueous phase into the solvent . Water, having a high volatility in organic media,is then easily stripped, distilled,or otherise removed from the solvent exytract. The removal of the co-extracted water lowers the solubility of the carboxylic acid, causing it to precipitate or form a concentrate in product form. Once the water and precipitated carboxylic acid are removed, the remaining solvent is ready to recycle. Berkeley National Laboratory's inventions energy-efficient. It removes the small amount of co-extracted water.

  REFERENCE NUMBER: IB-1206

• In a new invention, Berkeley Lab researchers Judson King and Scott Husson use carbon dioxide as an acidulent to sustain uptake capacity for sorption of carboxylic acids from aqueous solutions at pH>pKa1 of the acid. This approach addresses the problem of loss of uptake capacity due to pH-swing. In this approach, and Husson acidify the carboxylate salt solution with carbon dioxide gas and use solid sorbents, rather than liquid extractants, for the recovery of the carboxylic acid(s). The role of CO2 is to supply protons to convert the carboxylate salt into its corresponding carboxylic acid. The free acid can then be recovered by reversible reaction with a basic sorbent. Sorption is used to avoid potential problems of emulsion formation and aqueous-phase contamination that exist with extraction. An advantage of this sorption-regeneration scheme is that it avoids chemical consumption and waste salt generation; all materials are recoverable and recylable, including carbon dioxide, without substantially evaporating the solvent phase.

  REFERENCE NUMBER: IB-1360

STATUS:

• US Patents #5,104,492; #5,132,456; #5,412,126; #5,965,771, #6,316,668
• Available for licensing

REFERENCE NUMBER: See above

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