How to Measure the Greenness of Chemicals? A Case Study on Butadiene Production Applying Green Metrics and Life Cycle Assessment

The greenness of naphtha‐ and bioethanol‐based butadiene was compared using green metrics (GM) and life cycle assessment (LCA). GM provide predominantly qualitative results, showing advantages for bioethanol‐based butadiene. LCA indicates benefits of bioethanol‐based butadiene in terms of global warming and fossil resource consumption, but drawbacks in acidification, eutrophication, radiation, land use, ozone depletion, particulate matter, ozone formation, metal depletion, and freshwater consumption. When comparing both assessment approaches used, LCA offers a more comprehensive environmental assessment while GM is limited to a smaller section of the value chain but address additional aspects such as safety of chemicals. Green metrics and life cycle assessment as two alternatives in the greenness evaluation of chemical products and processes were applied in a case study comparing bioethanol‐ and naphtha‐based butadiene production. The findings of this paper reveal methodological and results‐related differences between both assessment approaches.