Towards a more virtuous synthesis?

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Although natural raw materials, attributed with all sorts of virtues, are particularly popular in perfumery and extensively promoted, the history of the sector has been rooted in chemistry since the late 19th century, and the perfumers’ palette is still mostly composed of molecules derived from synthesis. However, in the face of growing environmental concerns over the past decade, chemistry has become undesirable in the eyes of consumers – and therefore brands – who see it as polluting, toxic, energy-intensive and a major source of waste. However, this perception does not always match reality: a natural absolute, which requires a lot of space to grow, the use of petrochemical solvents and has a low yield, can be considered less sustainable than some synthetics which combine good yield, little waste and less impact on the environment. But in order to further reduce their compounds’ footprint on the planet, synthetic producers have adopted a greener approach to research and development. 

The idea of sustainable chemistry first emerged in 1998 under the name of Green Chemistry in a book by Americans John C. Warner and Paul T. Anastas. It is based on twelve principles that can be grouped into four overarching aims: resource management, waste prevention, safety and security, and energy saving. These are all areas of progress that guide the perfume industry in developing new molecules or obtaining existing ones in a more environmentally friendly manner. 

The first criterion by which these more sustainable ingredients are judged is their biodegradability, to ensure minimal pollution. “This is a problem we discovered for instance with Galaxolide, a cheap, resistant and therefore widely used musk^[1]Discovered in 1962,” explains Sylvain Antoniotti, research director at the CNRS [French national centre for scientific research] and director of the Flavours, Perfumes and Cosmetics Institute for Innovation and Partnerships at Université Côte d’Azur. “The trouble with this molecule is that, while it is not toxic, it accumulates in the environment, particularly in marine organisms. Today, we prefer to develop ingredients that have a longevity that corresponds to how long they are used.” This has resulted in the appearance over recent years of new molecules springing from industry research designed to tackle the problem. Two examples are IFF’s Cristalfizz, with its zesty notes, and Firmenich’s Dreamwood, inspired by Mysore sandalwood, which are biodegradable.

Natural in support of synthesis

Dreamwood also has the distinction of being made from 100% renewable carbon – the new hobbyhorse of composition houses in their work on sustainable synthesis. Carbon, the main component of fragrance compounds, has traditionally been obtained from fossil fuels, which are polluting and vanishing, and therefore hardly compatible with the notion of sustainable development. However, the industry is increasingly working with natural raw materials, which can form all or some of the synthons, i.e. the building blocks used as the foundation for producing the final ingredient. “When we reach 80% renewable carbon in a molecule, that’s a really good score,” says Cyril Gallardo, ingredients director at Mane. 

While all companies have made great strides in this direction in recent years, Japan’s Takasago is a pioneer in the field. It has specialised in pine oil chemistry, which gives it an extensive portfolio of synthesised ingredients thanks to the carbon the oil contains, particularly L-citronellol and L-cis-rose oxide, rose-like notes that are widely used in fine fragrances. As early as 2014, Takasago was the first to indicate the percentage of renewable carbon in all its raw materials with its Biobased index. In 2019, Givaudan implemented the FiveCarbon Path programme, which uses a number of green chemistry principles applied to carbon and, notably, plans to prioritize the use of bio-sourced carbon (i.e. obtained from organic and renewable matter) to create ingredients. To further reduce the environmental impact, this renewable carbon can be derived from waste or by-products, in line with the upcycling principle: Symrise’s Lilybelle, with its lily of the valley fragrance, is produced from limonene extracted from fruit juice industry waste, while Givaudan’s Akigalawood, with its peppery woody nuances, is obtained using biotechnologies from a fraction of patchouli essence that has no olfactory interest.

Fermentation replacing chemical reagents

Biotechnologies represent the other major tool the perfume industry uses to manufacture sustainable molecules. This involves drawing on the properties of micro-organisms (enzymes, bacteria, etc.), sometimes genetically modified, to transform a natural raw material into one or more odorous compounds by means of a fermentation process that replaces part of the chemical reagents, or even all of them, in which case the molecule is then considered natural by IFRA. This process has led to the development of Clearwood in 2014 by Firmenich to replace patchouli oil, Biomuguet by Takasago, and various lactones by Mane. “Biotechnologies are extremely compatible with sustainable chemistry,” stresses Sylvain Antoniotti. “They use renewable materials, consume little energy, are very efficient, produce little or no waste, and they are completely safe for the technician and the environment.”

An impressive list of benefits, but how big a part do they play in the perfumers’ palette? Although we hear a lot about these “green” molecules, whose development certainly is in full swing, they are still very much in the minority compared to those derived from traditional chemistry. At Mane, for example, the ratio is a few dozen out of 2,000 in the ingredients portfolio. However, Xavier Fernandez, professor at the Nice Institute of Chemistry and director of the Foqual (formulation, analysis, quality) chemistry master’s degree at Université Côte d’Azur, observes that “there is a real desire on the part of companies to shift towards sustainable synthesis. In a few years’ time, their products will probably be given an environmental rating, rather like the Nutri-Score, and they know they will have to be ready. In addition to the ecological benefits, this approach is good for their image and will soon be profitable from a financial point of view, when this is not already the case.”

Musks and solvents in the firing line

It is true that sustainable synthesis currently produces molecules that are on average more expensive than their conventional equivalents. “It varies greatly depending on the yield, the number of processing stages, the need (or not) for purification, and so on,” explains Cyril Gallardo. In the case of Vinyl Guaiacol, with its whisky and clove flavour, the molecule obtained by biotech is less expensive than that produced by conventional synthesis: it therefore now replaces it in all formulas. But some ingredients can be up to ten times more expensive. “Few of our customers are willing to follow suit, unless they make naturalness a sine qua non,” says the ingredients director. But these price differences could soon be reduced or even disappear. “Technical progress and the increasing scarcity of oil will make sustainable processes more and more profitable, and perfumers’ palettes will “naturally” tend towards 100% bio-based products,” Sylvain Antoniotti predicts. “Today, we are able to obtain all molecules through biotechnology or from renewable carbon. But sometimes petrochemical synthesis is still the most efficient: if it only involves one step, replacing it with a natural process that requires dozens of steps would not be appropriate for the environment. These different methods will therefore continue to coexist,” says Cyril Gallardo. The research undertaken by composition houses currently focuses on musks and 100% renewable solvents. If they manage to replace the classic solvents – such as dipropylene glycol, which is often petrochemical-based – used extensively to dilute raw materials and, consequently, formulas, they could contribute to drastically changing the environmental footprint of fragrance concentrates. “Given the place that solvents occupy in formulas, these formulas will soon be composed of more than 50% sustainable molecules, once they have been developed,” predicts Cyril Gallardo.

This new approach to chemistry, while still marginal, should gain ground in the coming years, gradually erasing the age-old frontier between natural and synthetic.

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Summary

• Is sustainable perfumery possible?, by Jeanne Doré
• Natural raw materials: plants, essences and people, by Jessica Mignot
• Towards a more virtuous synthesis?, by Anne-Sophie Hojlo
• Responsible formulation: different tools, one ideal, by Sarah Bouasse
• Inside the lab: rationalising, not rationing!, by Aurélie Dematons
• When packaging goes green, by Delphine de Swardt
• Scents in circulation: perfume life cycles, by Clément Paradis