Matthias Kunze, Business Development Manager, LANXESS
Preservatives containing green toluene pass practical testing in life cycle assessment
How can you measure a product’s sustainability?
The most common method to date is to calculate a product’s CO2 footprint. This method focuses exclusively on greenhouse gas emissions and their impact on climate change and global warming. This includes CO2 emissions from the company’s own production and emissions from the energy purchased for that purpose, as well as the CO2 content of the raw materials used and emissions caused by logistics.
However, Life Cycle Assessment (LCA) is also increasingly being used—a method already employed by numerous companies in the chemical, packaging, and consumer goods industries. This method considers a significantly broader spectrum of environmental impacts to determine a product’s environmental footprint. LCA is based not only on a single metric but on multiple indicators—each specific to the environmental category under consideration. These categories include, for example:
- Resource use
- Ecotoxicity, i.e., the impact of substances on freshwater ecosystems
- Acidification of soil or water
- Ozone Layer Depletion
- Eutrophication of water bodies
- Land use
The CO2 footprint is therefore well-suited for quantifying progress toward climate goals using a single metric; Life Cycle Assessment, on the other hand, takes a more holistic view of sustainability and provides a metric for each category examined.
How sustainable is a product according to Life Cycle Assessment?
Matthias Kunze, Business Development Manager at the speciality chemicals company LANXESS, examined how LCA criteria affect the evaluation of a specific product using the example of the sodium benzoate “Purox S Scopeblue.” The product is used as a preservative in personal care products, food, and pharmaceuticals. In the manufacturing process, conventional toluene is replaced with “green” toluene made from 100 per cent used cooking oil. This alone significantly reduces the product’s CO2 footprint. LANXESS’s “Scopeblue” products either contain at least 50 per cent sustainable raw materials or have a CO2 footprint that is at least 50 per cent lower than that of conventional products.
When evaluated according to LCA criteria, conventional sodium benzoate also performs very well. In nearly all LCA categories, the use of “green” toluene derived from used cooking oil in the production of sodium benzoate has a significantly positive impact. Particularly in the categories “resource use” and “acidification,” the values are lower compared to sodium benzoate made with conventional toluene. Matthias Kunze: “Preservatives such as sodium benzoate sometimes carry disproportionate weight in specific environmental categories within the LCA, even though they often make up less than one percent of a formulation. ”
In some categories, however, there are also opposing effects, albeit at a low level. Plant based products sometimes perform significantly worse than petrochemical products. In the case of sodium benzoate with “green” toluene, the value increases by about 30 percent in the “eutrophication of water bodies” category. However, it is still significantly lower than that of sustainable products based on plants grown specifically for that product. Even in the “land use” category—that is, environmental impacts resulting from the use or conversion of land— the use of “green” toluene has only a slightly negative effect.
Determination of the Life Cycle Assessment
When conducting the LCA, LANXESS follows the “cradle-to-gate” approach, which includes the raw materials used, transportation to the production site, and production—including the energy used for this purpose—in the life cycle assessment of the respective product. Additionally, the output of the manufacturing process—such as water and air emissions—is factored into the assessment.
Matthias Kunze adds: “Beyond the aspects of traditional LCA analysis, there is another factor to consider with preservatives: they extend a product’s shelf life both in retail and during use by consumers. Ultimately, this helps prevent waste and conserve resources—a positive factor for the life cycle assessment that is becoming increasingly important in holistic sustainability evaluations.”
Conclusion
Life Cycle Assessment (LCA) does not merely determine a single sustainability metric for a product, as is the case with the CO2 footprint. It examines a wide range of environmental categories. Manufacturers or consumers must therefore select the categories that are relevant to their decisions and their assessment of a product.
Purox sodium benzoate performs well in both analysis methods. The already low CO2 footprint of the conventional product variant is reduced even further through the use of a recycled raw material—toluene derived from used cooking oil.
Within the life cycle assessment, the conventional sodium benzoate already achieves a good result in all categories compared to other preservatives. The “green” variant delivers even better values in almost all LCA categories. Exceptions are the aspects “land use” and “eutrophication of water bodies”; here, the environmental performance deteriorates slightly. However, compared to other preservatives, the values in these categories remain at a very low level. Purox S Scopeblue is therefore already well-equipped today for a holistic sustainability assessment, which will become increasingly important in the future.
