Life Cycle Sustainability Assessment for the Bioeconomy: The Case of the Production of Tramadol from 2-Methyltetrahydrofuran

Abstract

In the context of the bioeconomy, the transition from fossil-based to bio-based chemicals holds promise in reducing dependence on non-renewable resources and mitigating the impacts of climate change. However, the sustainability performance, encompassing environmental, social, and economic aspects, still needs to be demonstrated for emerging bio-based chemicals. Here, we undertake an integrated life cycle sustainability assessment (LCSA) to evaluate and compare a bio-based solvent with its fossil-based counterpart. Our methodological approach integrates the assessment of all three dimensions of sustainability at the inventory level within the LCSA framework to enhance its operationality. Therefore, this publication compares the environmental and social impacts as well as the costs related to the use of 2-methyltetrahydrofuran from bagasse (2-MeTHF B) and from corncobs (2-MeTHF C) and tetrahydrofuran to solvate the reaction media for producing 1 kg of tramadol, an opioid analgesic medication. The results reveal a complex trade-off. 2-MeTHF demonstrates lower environmental impacts (∼7574 μPts for 2-MeTHF B, ∼8961 μPts for 2-MeTHF C, and ∼21490 μPts for THF) and more particularly less climate change impacts (3.24 kg of CO₂ equiv for 2-MeTHF B, 4.4 kg of CO₂ equiv for 2-MeTHF C, and 14.9 kg of CO₂ equiv for THF). However, it has worse social aspects (∼558 medium-risk hours for 2-MeTHF B, ∼840 medium-risk hours for 2-MeTHF C, and ∼173 medium-risk hours for THF) and costs (10.44 USD for 2-MeTHF B and C and 5.4 USD for THF). Geographical aspects of the value chain drive most of the impacts and risks showcased in this study. Optimizing the value chain would help to mitigate life cycle environmental impacts and socio-economic risks associated with 2-MeTHF. Energy optimization in synthesis processes is identified as a key strategy to reduce potential environmental impacts. The level of implementation of the 10 principles of the Life Cycle Initiative is discussed, revealing complete alignment with 5 of the 10 principles. In contrast, four principles exhibit medium alignment, and one is not implemented. Data availability and confidentiality challenges are recognized as hindrances to transparency and replicability. In conclusion, the study emphasizes the necessity of involving diverse stakeholders in enhancing the relevancy of sustainability assessments. Companies in the bioeconomy are encouraged to implement Environmental Management Systems and Corporate Social Responsibility approaches to infuse sustainability practices within their value chains.