Enantiomerically pure b-amino acids are key building blocks for the synthesis of pharmaceuticals. Special consideration will be given to the production of (S)-3-aminobutanoic acid. Mass balancing is encouraged and highlighted to support the decision-making process in early stages of synthesis design when alternative routes are available. Though the overall yield of a chemical approach is twice as good as a chemoenzymatic route, the latter is more convincing regarding raw material consumption and costs as well as health issues. The energy flow analysis in early process development could not yet be carried out but principles concerning the modeling of energy demand were briefly exemplified by a comparative study of two processes with respect to decanoic acid methyl ester.

An improved, greener process for the enantioselective chemoenzymatic synthesis of (S)-3-aminobutanoic acid has been developed. Reaction steps comprise an initial aza-Michael addition starting from cheap prochiral compounds, subsequent enzymatic resolution via aminolysis using commercially available Candida antarctica lipase B in a solvent-free one-pot process, hydrolysis of the resulting ester and removal of the N-benzyl moiety via hydrogenation. After isolation, the desired (S)-3-aminobutanoic acid was obtained in an overall yield of 28% and with an excellent enantiomeric excess of 99% ee. Notably, this reaction sequence does not require column chromatography with organic solvents and only one purification step of an intermediate is needed. The environmental impact of this optimized process has been evaluated and an E-factor of 41 has been calculated for the overall process. A comparative assessment with the previous process was done via mass balancing using the E-factor, the selectivity index S -1 as well as an SHE assessment.

No abstract

Application of Metrics in Early Stages of Process Development -Two Case StudiesIt is reasonable to use methods from the environment, health and safety management as well as from life cycle assessment already in early stages of process development. Against the background of poor data availability and data quality applications of metrics in early stages of process development are presented for two case studies. A comparative assessment of two alternative synthesis routes to the production of an enantiomerically pure b-amino acid has been realized. In addition to the analysis of the mass flows, material costs and different health assessment methods were explored. Using the example of the glutaraldehyde production it is demonstrated how the cumulated energy demand can be calculated with software tools in early stages of process development.

No abstract

Biotechnical technologies are often viewed as generally green processes, since they operate at low temperatures and pressures. However, as shown by various comparative studies of chemical and biotechnical engineering processes, this view cannot be generalized. It is clear that sustainable assessment should be carried out in the early stages of process development, since these stages have a major influence on the economic and ecological performance of processes later at the industrial scale. One option to use as a basis for evaluating the potential advantages to developing a biotechnical process can be a material and energy flow analysis (MEFA) at an early stage. This article provides an understanding of MEFA in general and illustrates its successful application by means of two case studies.

No abstract

No abstract