Chemical industry and Life Cycle Assessment

1. Introduction Chemical industry represents one of the sectors with major consumptions in Europe. An energy demand of 2,159 PJ was accounted for 2021, corresponding to 21% of the whole industrial sector request [1]. The same amount is also confirmed at global level [2]. Oil and gas represent the main feedstocks [3], either for the material and energy [2] production confirming its lower grade of renewability. However, starting from 90’s, the adoption of the green chemistry principles [4] allowed to increase the environmental sensitivity and several goals were achieved: -54% on greenhouse gases emissions, -33% on waste production and -50% of the polluted water discharged [5]. Green and environmental chemistry are those disciplines that encourage the minimization of waste, avoiding unnecessary derivatization and designing for degradation; the utilization of renewable sources, in replacement of the more consolidated; the development of safe reactions, by also designing safer chemicals; the online control of processes, for pollution and accidents prevention. 2. Results and Discussion Green and environmental chemistry need some tools to address the environmental and social feasibility of a reaction under study. Among these, Life Cycle Assessment (LCA) is an analytical branch of the "Life Cycle Thinking" approach, which can provide important information about the consequences of anthropic activities from a systemic point of view. It is aimed at quantifying environmental impacts starting from the collection of many inventory data; thus, similarly to any other scientific analytical methodologies, data quality requirements should address many features, like precision, completeness, representativeness, consistency, reproducibility, uncertainty. LCA is a standardized approach (ISO 14040-14044) and worldwide recognized by the sector as one of the key methods [6]. In these years, LCA was applied to several reactions briefly described below. The production of acrylonitrile to identify the most suitable reagent between propylene and propane. The synthesis of acrolein from glycerol to compare the usage of rapeseed oil vs beef tallow as starting materials. The production of bio-butadiene to counterpose the single-step pathway with the two-steps route. The sildenafil citrate synthesis to underline the benefits from the application of the green chemistry principles from the fist preparation up to the commercialization of an active pharmaceutical ingredient. The recovery of glycidol from a reaction waste streams of the Epicerol® process. The preparation of acetonitrile from bio-ethanol, combining LCA with process simulation. The synthesis of 100% bio-PET, one of the major commodities worldwide. The bio-based routes to maleic anhydride at pilot scale, for selecting the best building block (furfural or butanol). The methyl methacrylate production, to evaluate the potentialities of substituting formaldehyde with its production in situ. And, finally, the Guerbet reaction for the preparation of bio-based butanol from second generation alcohol. 3. Conclusions Life Cycle Assessment can integrate, from a systemic standpoint, data concerning the environmental effects of chemical substances monitored by the classical approach of environmental analytical chemistry. A LCA is always recommended when the chemical sector is under study. Reactions can be studied at laboratory scale as well as at pilot and industrial level to select the best precursors, evaluate different catalytic systems and compare several conditions. These achievements were obtained thanks to a strict cooperation with many colleagues, undergraduate and PhD students to whom I should express my greatest appreciation. References [1] eurostat 2023, “Final energy consumption in industry - detailed statistics”. [2] IEA (International Energy Agency) 2023, https://www.iea.org/fuels-and-technologies/chemicals. [3] IEA (International Energy Agency), https://www.iea.org/reports/chemicals. [4] P.T. Anastas, J.C. Warner, Green Chemistry: Theory and Practice, Oxford University Press, 1998. [5] Cefic (the European Chemical Industry Council) 2023 https://cefic.org/a-pillar-of-the-european-economy/facts-andfigures-of-the-european-chemical-industry/environmental-performance/. [6] Green Chem., 2018, 20, 1929-1961.