Lactic acid, environmentally benign

Ethyl lactate is another lactic acid derivative that has recently been commercialized. An environmentally benign solvent with properties superior to many conventional petroleum-based solvents, it can be blended with methyl soyate derived from soybean oil to create custom-tailored solvents for various applications. 

Tsuneizumi et al. [13] studied the chemical recycling of poly(lactic acid)-based polymer blends using environmentally benign catalysts, clay catalysts, and enzymes. Poly(L-lactic acid) (PLLA)-based polymer blends (e.g., PLLA/polyethylene [PE] and PLLA/poly(butylenes succinate) [PBS]) were degraded into repolymerizable oligomer. 

These halogenated solvents, especially chloroform, pose a high risk not only to the environment, but also to the personnel working with them. In order to avoid leaving the patterns of sustainability in biopolymer production, it will be indispensable to concentrate the development of new extraction processes on such recyclable solvents that are also of an environmentally benign nature, such as lactic acid esters [73]. 

Eco-friendly biodegradable polymers and biocomposites are relatively novel materials that can contribute to reduce the dependence on fossil sources. Because of their renewable nature and biodegradability, environmentally benign composite materials with properties comparable to those of some widely used commodities can be produced. Py-GC/MS has developed as a useful tool for the study of thermal degradation of such polymers and composites, and many studies have recently been published for biodegradable polymers, such as polycaprolactone (PCL), polyhydroxyalcanoates (PHAs) and their copolymers,poly(lactic acid) (PLA), and carbohydrates, including starch and cellulose. 

Lehermeier, H.J., Dorgan, J.R., 2000. Poly(lactic acid) properties and prospect of an environmentally benign plastic melt rheology of linear and branched blends. In Fourteenth symposium on thermophysical properties. 

Ethyl lactate (ethyl 2-hydroxypropionate) is a nontoxic biodegradable compoxmd naturally found in a variety of food and industrially produced via esterification of lactic acid with ethanol [149]. Both of the components for the production of ethyl lactate are derived from renewable raw material (including low-cost agricultural waste) mainly by the fermentation process. This environmentally benign solvent with high boiling point (154 °C) and low volatility has properties superior to many conventional petroleum-based solvents and can substitute them as an eco-friendly alternative in many reactions [150,151]. The applications of ethyl lactate as a medium for the multicomponent heterocyclic synthesis are exemplified below. 

Ethyl lactate is another lactic acid derivative that has been commercialized. An environmentally benign solvent with properties better than that of many conventional petroleum-based solvents, it can be mixed with methyl soyate obtained from soybean oil to produce custom-tailored solvents for various applications. The utilization of ethyl lactate has been limited due to its high manufacturing costs selling prices for ethyl lactate have varied between 3.30 and 4.40/kg, as compared with 2.00 and 3.75/kg for conventional solvents. Owing to advancements in lactic acid fermentation, separations, and conversion technologies, retail costs have been reduced to as low as 1.87/kg (Carole et al., 2004). 

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