Renewable Solvents 2 Chemical Examples

Fermentation-derived organic acids and their esters are potentially important chemical feedstocks for polymers and specialty polymers, but most significantly as alternative solvents for industrial and consumer applications. For example, lactate esters are derived from renewable carbohydrate raw materials such as cornstarch. They exhibit much lower toxicity compared with halogenated hydrocarbons and ethylene glycol ethers and are environmentally benign. Some studies suggested that lactate ester solvents have the potential of replacing petroleum-based solvents... 

The metal-catalyzed oxidation of carbohydrates with molecular oxygen is a remarkable example of green chemistry because reactants are obtained from renewable resources, processes are conducted under mild conditions with air as oxidizing agent and water as solvent, and reaction products are environmentally benign because of their biodegradability. In addition oxidized carbohydrate derivatives can often be obtained with high selectivity, and the catalysts are recyclable. These catalytic processes are, therefore, potentially very attractive for the preparation of specialties or intermediates employed in the food, cosmetic, pharmaceutical, and chemical industries. 

The ionic liquids described here are reported to be extremely fast and efficient media with which to dissolve bacterial cellulose. In addition, due to the large number of potential combination of anions and cation, it is likely that increasing numbers of ionic liquids that can dissolve this high molecular weight cellulose will be found. For example, it has been suggested that ionic liquids with acetate counter ions will be extremely effective for this task. [141]. The ability to dissolve and recover bacterial cellulose, as well as the environmental benefits of using renewable and recyclable solvents, creates further possibilities to chemically modify this molecule to alter its properties in order to use bacterial cellulose to create composites. 

The example presented here illustrates the fact that supercritical technologies may have huge potential for a variety of chemical processes, although the supercritical solvent as such would not be needed. In light of this example, another current hot topic, biodiesel processing from renewable resources, could presumably also benefit from this technology. 

As an answer to the growing demand for products made from renewable resources and with (modified) starch as a reference in mind, a lot of these starches have been devoted to the chemical modification of inulin [3]. Hydrophobization of inulin, e.g. grafting of alkyl chains on to the inulin backbone and as such obtaining an inulin derivative showing the wanted amphiphilic character, can be done in several ways by esterification, by etherification or by carbamoylation. The reactions are usually performed in solvents like pyridine, dimethylformamide or dimethylsulfoxide, using catalysts like, for example, sodium acetate, potassium carbonate or triethylamine. 

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