Lactic acid, the most widely occurring hydroxycarboxylic acid, is an enigmatic chemical. It was discovered a long time ago and its use in food preservation and processing and as a specialty chemical has grown over the years with current production of about 120 000 t yr −1 . Its potential as a major chemical feedstock, derived from renewable carbohydrates by sustainable technologies, to make plastics, fibers, solvents and oxygenated chemicals, had also been recognized. Recently, new technologies have emerged that can overcome major barriers in separations and purification and processing. Advances in electrodialysis (ED) and bipolar membranes and one particular process configuration termed the 'double ED' process, a specific combination of desalting ED followed by 'water-splitting' ED with bipolar membranes, has given very promising results, showing a strong potential for an efficient and economic process for recovery and purification of lactic acid without generating a salt waste. For the production of polymers, several advances in catalysts and process improvements have occurred in the technology to produce dilactide and its polymerization to produce plastics and fibers by Natureworks LLC, which is the leader in lactic polymer technology and markets. Other advances in esterification technology with pervaporation and development of biosolvent blends also have a high potential for 'green' solvents in many applications. Recently, a considerable amount of pioneering effort in technology, product development and commercialization has been expended by several companies. To overcome the barriers to replace long-established petroleum-derived products, further real support from consumer, regulatory and government organizations is also needed.

Lactic acid has been an intermediate‐volume specialty chemical (world production ∼ 40,000 tons/yr) used in a wide range of food processing and industrial applications. Lactic acid has the potential of becoming a very large volume, commodity‐chemical intermediate produced from renewable carbohydrates for use as feedstocks for biodegradable polymers, oxygenated chemicals, plant growth regulators, environmentally friendly ‘green’ solvents, and specialty chemical intermediates. The recent announcements of new development‐scale plants for producing lactic acid and polymer intermediates by major U.S. companies, such as Cargill, Ecochem (DuPont/ConAgra), and Archer Daniels Midland, attest to this potential. In the past, efficient and economical technologies for the recovery and purification of lactic acid from crude fermentation broths and the conversion of lactic acid to the chemical or polymer intermediates had been the key technology impediments and main process cost centers. The development and deployment of novel separations technologies, such as electrodialysis (ED) with bipolar membranes, extractive distillations integrated with fermentation, and chemical conversion, can enable low‐cost production with continuous processes in large‐scale operations. The use of bipolar ED can virtually eliminate the salt or gypsum waste produced in the current lactic acid processes. Thus, the emerging technologies can use environmentally sound processes to produce environmentally useful products from lactic acid. The process economics of some of these processes and products can also be quite attractive. In this paper, the recent technical advances in lactic and polyactic acid processes are discussed. The economic potential and manufacturing cost estimates of several products and process options are presented. The technical accomplishments at Argonne National Laboratory (ANL) and the future directions of this program at ANL are discussed.

Lactic acid has been an intermediate-volume specialty chemical (world production ~50,000 tons/yr) used in a wide range of food processing and industrial applications. Lactic acid has the potential of becoming a very large volume, commodity-chemical intermediate produced from renewable carbohydrates for use as feedstocks for biodegradable polymers, oxygenated chemicals, environmentally friendly "green" solvents, plant growth regulators, and specialty chemical intermediates. The recent announcements of plant expansions and building of new development-scale plants for producing lactic acid and/or polymer intermediates by major U.S. companies, such as Cargill, Chronopol, A.E. Staley, and Archer Daniels Midland (ADM), attest to this potential. In the past, efficient and economical technologies for the recovery and purification of lactic acid from crude fermentation broths and the conversion of lactic acid to the chemical or polymer intermediates had been the key technology impediments and main process cost centers. The development and deployment of novel separations technologies, such as electrodialysis (ED) with bipolar membranes, extractive distillations integrated with fermentation, and chemical conversion, can enable low-cost production with continuous processes in large-scale operations. The use of bipolar ED can virtually eliminate the salt or gypsum waste produced in the current lactic acid processes. Thus, the emerging technologies can use environmentally sound processes to produce environmentally useful products from lactic acid. The process economics of some of these processes and products can also be quite attractive. In this paper, potential products and recent technical advances in lactic and polylactic acid processes are discussed. The technical accomplishments at Argonne National Laboratory (ANL) and the future directions of this program at ANL are discussed.

Hydroxycarboxylic acids are an important group of chemicals, with several members that are commercially manufactured in large volumes and have a wide range of applications. Two α‐hydroxycarboxylic acids, lactic and glycolic, and a derivative of γ‐hydroxycarboxylic acid γ‐butyrolactone are discussed in detail because of their relative commercial importance, both current and future. General classes of reactions that these acids undergo are also discussed, with specific examples of those reactions that are or could become commercially important. Current manufacturing processes for lactic and glycolic acids and γ‐butyrolactone are briefly outlined, with estimates of the production volume and market size for various applications. For lactic acid production and manufacture of its derivatives for biodegradable polymers, new processes are emerging, and some of the recent patents and emerging technologies are highlighted. Some of the important uses of hydroxycarboxylic acids are related to environmentally friendly products and processes such as biodegradable plastics for consumer products and nontoxic and easily degradable solvents, cleaning agents, plasticizers, etc. The emergence of new technologies for efficient and economical manufacture of these chemicals, combined with these product opportunities, could make these hydroxycarboxylic acids very large‐volume chemicals of global commercial importance.

Hydroxycarboxylic acids are an important group of chemicals, with several members that are commercially manufactured in large volumes and have a wide range of applications. Two α‐hydroxycarboxylic acids, lactic and glycolic, and a derivative of γ‐hydroxycarboxylic acid γ‐butyrolactone are discussed in detail because of their relative commercial importance, both current and future. General classes of reactions that these acids undergo are also discussed, with specific examples of those reactions that are or could become commercially important. Current manufacturing processes for lactic and glycolic acids and γ‐butyrolactone are briefly outlined, with estimates of the production volume and market size for various applications. For lactic acid production and manufacture of its derivatives for biodegradable polymers, new processes are emerging, and some of the recent patents and emerging technologies are highlighted. Some of the important uses of hydroxycarboxylic acids are related to environmentally friendly products and processes such as biodegradable plastics for consumer products and nontoxic and easily degradable solvents, cleaning agents, plasticizers, etc. The emergence of new technologies for efficient and economical manufacture of these chemicals, combined with these product opportunities, could make these hydroxycarboxylic acids very large‐volume chemicals of global commercial importance.