Identification by Life Cycle Assessment of the critical stage in the synthesis of nopol

What is it about?

Nopol is a fine chemical obtained from Prins reaction between β-pinene that is a pine derivative and paraformaldehyde; this alcohol has several applications in the aromas and fragrances industry, agrochemicals, pharmaceuticals and household products. The current knowledge gap with this contribution is evaluate the environmental impacts of nopol synthesis by two alternative processes using the Life Cycle Assessment approach, which was developed according to the methodological structure of ISO standards with a “cradle-to-gate” scope, analysis that has not been reported so far in the literature. The Life Cycle Inventory was carried out according to primary and secondary data, where Aspen Plus® was used. Hierarchist ReCiPe v1.13 (2008) was used as a methodology for the Life Cycle Impact Assessment using the Umberto LCA+ software with the Ecoinvent v3.6 database. The results showed that, in general, raw materials extraction contributes to a much greater extent in the environmental burdens than production process phase. It was found that the hotspot of the process is the solvent; greater environmental benefits were obtained when ethyl acetate was recirculated to the process, despite the additional required unit operations such as distillation tower and heat exchanger. The fossil depletion potential was the impact category with the highest score in points followed by climate change potential and agricultural land occupation potential. The carbon footprint of nopol catalytic synthesis was 13.0 and 37.4 kg CO2-Eq for system with solvent recirculation and without recirculation, respectively, which are less than reported values for a fine chemistry product as an active pharmaceutical ingredient. As options to decrease the environmental burdens of the studied nopol production process, it is proposed to optimize the fossil resources, evaluate the recirculation, replace or decrease solvent amount; also the evaluation of other heterogeneous catalytic systems and appropriate reaction conditions is proposed.

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Why is it important?

There are some reports about the pharmaceutical industry and its sustainability, that highlight the limitation for the integration of LCA studies in this kind of industry owing mainly to: the lack of incorporation of social sustainability and process economics in available tools, and lack of uniform data due to that facilities are dispersed, i.e., batch processes in different locations, making energy inventories very difficult. Sustainable development is the creation of economic and social development by means of preservation of natural fundamentals of life and an achievement of economic and social welfare for present and future generations, for us and globally. Life cycle sustainability assessment refers to the evaluation of all environmental, social and economic negative impacts and benefits in decision-making processes towards more sustainable products throughout their life cycle. This contribution is addressed to contribute with the twelfth goal of the Sustainable Development Goals, related with the responsible consumption and production. The efficient management of natural resources and the way of toxic wastes and pollutants disposal, are important targets to achieve this goal. This manuscript reports a LCA for a chemical process where a component of an essential oil, such as β-pinene, is used to obtain high-added value product such as nopol, information that is unavailable in existing literature. The goal of this contribution is to develop a first approximation of LCA study for nopol catalytic synthesis from βpinene by comparison between two alternative processes, identifying its environmental impacts and evaluating the unit processes that give the most significant environmental input-output flows, i.e., hotspots. Results of this research will give relevant information for future LCA studies in chemical processes and particularly, in the synthesis of fine chemical products. By identification of the main environmental burdens, processes could be optimized by modifications or improvements that make it more environmental friendly.