Environmentally benign chemical processing in expanded solvents

Concerns about public health and the environment are pushing the chemical industry to cleaner and more environmentally friendly processes. Acid catalysts require neutralization and disposal, and chlorinated organic solvents must be completely removed from products and recovered. In this work, these concerns are addressed with benign alternatives to conventional chemical processing that avoid hazardous solvents and eliminate waste byproducts. Hazardous solvents and catalysts have been replaced with more benign solvents at elevated temperatures and pressures that can be tuned to act as the solvent and catalyst while being easily separable from final products.; Water and acetic acid were used to replace environmentally undesirable catalysts and solvents while improving mass transfer by changing from heterogeneous to homogeneous systems. The solvent power of dimethyl ether was tuned to remove a desired reaction intermediate selectively from a reactant catalyst mixture before subsequent reaction to byproducts could take place. This selective extraction was followed by facile separation of the product from dimethyl ether by depressurization. Along with the scouting of potential reactions and processes where expanded solvents offer strong technical and economic advantages, the elements necessary for industrial scale-up such as the phase equilibria, reaction rates, and reaction equilibria have been measured.