Chemical process industries solvent substitution

Spent solvents constitute a major source of pollution in the chemical and pharmaceutical industries. Much of this pollution can be prevented by solvent substitution using solvents that are more environmentally compatible or possess higher performance. This can lead to a reduction in the amount used. However, identifying replacement solvents is often a difficult process performed in an ad hoc manner. 

The Simons ECF process was subsequently developed to an industrial production process by the 3M Company. It currently provides the precursors to the palette of more than 250 large-scale fluorine-containing compounds produced by this company [27]. These products include fluorotensides, fire-fighting chemicals, per-fluorinated solvents, and artificial blood substitutes. 

Most organic liquids can act as a solvent in industrial processes. Solvents are an important component in the chemical industry processes and in the application industries that utilize solvents as ingredients in their products. Many of the organic solvents described in this book also serve as chemical intermediates in preparation of other valuable organic chemicals. The data on the solvents included in this book was extracted from product literature given to the author by the various solvent producers. This data reflects the most current physical properties as well as the current use opportunities for the solvents and the most recent environmental and safety data. Environmental concerns often mandate solvent substitution. 

In the petroleum industry, dewaxing solvents are separated by ultrafiltration from dewaxed oils by chemically resistant membranes made from polysulfone or polyimide. In a related process, pentane is separated from deasphalted heavy oil under conditions intermediate between reverse osmosis and ultrafilttation (ca. 15 bar applied pressure). High-molecular-weight hydrocarbons in the oil form a gel layer on the surface of a polysulfone support membrane. This gel restricts passage of heavier hydrocarbons but not pentane, which is recovered as permeate. To separate other hydrocarbon mixtures that do not contain gel-forming components, polymeric additives would be used as a rejecting barrier substitute. 

Surely, the concepts and paradigms of ionic liquids are new and still not fully accepted in the wider community many chemists consider with some skepticism the possibility of applying ILs as substitutes of common solvents in large-scale processes. Moreover, as has been recently evidenced,there are several prerequisites that determine the choices of development chemists working in the fine chemical industry ... 

Even though there are so many advantages to using enzymes as substitutes for chemical catalysts, practical applications of enzyme catalysis are few and far between. This is largely due to their relatively poor stabilities and catalytic activities under the conditions that characterize industrial processes high temperatures, extremes of pH or non-aqueous solvents. Enzymes evolved for the survival benefit of an organism may not exhibit features essential for in vitro application (30). 

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