We described the first synthesis of biobased ethyl and methyl formates. The synthetic strategy is based on the transesterification of natural geranyl and citronellyl formates derived from Pelargonium species essential oils with ethanol or methanol, promoted by an ecocatalyst (R). Good yields (up to 80%) were obtained with an excellent selectivity.

This chapter is dedicated to the starting point of ecocatalysis: the conservation and restoration of terrestrial and aquatic ecosystems. An assessment of the phytoremediation programmes conducted by the Grison group in the last two decades is presented here. Pioneering endemic plant species, such as Noccaea caerulescens, Anthyllis vulneraria, Geissois pruinosa and various species of Grevillea, have been reintroduced on large-scale open fields in severely degraded areas of South of France and New Caledonia for removal of trace elements (mainly Zn, Ni and Mn) by phytoextraction. Aquatic plant species, such as Eichhornia crassipes, Ludwigia peploides and Pistia stratiotes, were used for rhizofiltration experiments and root-based filters were derivatised for the biosorption of many trace elements and rare-earth elements (As, Cd, Ce, Co, Cu, Eu, Fe, Ir, Ni, Pb, Pd, Pt, Rh, Ru, Sc, and Yb). The Grison group focus not only concerns the restoration of polluted areas but also the management of invasive alien species, such as Fallopia japonica and Arundo donax, to assist both conservation and restoration efforts in wetlands.

Pollution is one of the 5 key factors responsible for the decline of biodiversity. Metal pollution caused by human activities is particularly serious, because metals are not biodegradable. This chapter is an introduction to the development of solutions from Nature, on which the concept of ecocatalysis is based. The rehabilitation and restoration of degraded and polluted terrestrial and aquatic ecosystems are the starting point of ecocatalysis. Phytoextraction, rhizofiltration and biosorption, which are phyto-based techniques using adaptative capacities of terrestrial and aquatic plant species, were introduced here, since they have been mainly developed for use in ecocatalysis (see Chapter 2). In each case, plant biomasses, which are full of metals, were valorized in organic chemistry catalysis, implementing a new field of green and sustainable organic chemistry (see Chapters 3 and 4). This valorisation of biomass generates a socio-economic dimension to ecological solutions and is based on the pillars of sustainable development and the preservation of biodiversity.

Ecocatalysis is an emerging area of catalysis that has been well-developed over the past 20 years. Ecocatalysis displays a wide toolbox of biosourced mineral catalysts with high performances, selectivity and adjustable reactivity, while respecting the principles of sustainable and green chemistry for the preparation of ecocatalysts® and for the synthesis of compounds of interest. Ecocatalysis has successfully revisited most of the main mechanisms in organic synthesis that are presented in this chapter: Lewis and Brønsted acid catalysis, base catalysis, and reduction, oxidation, and cross-coupling reactions.

Ecocatalysts® are powerful catalysts that are derived from different types of biomasses (leaves, roots or seeds). The biomasses correspond to plant species that, in some cases, can accumulate metals by phytotechnologies (phytoextraction, rhizofiltration or biosorption). A crucial feature of ecocatalysts® is hence their polymetallic composition due to their natural origin: a mineral matrix made up of physiological elements, containing an accumulated transition element if a phytotechnology was used. This chapter is dedicated to the materials chemistry of ecocatalysts®: analysis of their composition, morphology, and structure. The vegetal footprint of the ecocatalysts® and the unexpected mineral biodiversity were discussed in relation to their structure and method of preparation.

In the last 30 years, the use of herbicides worldwide has doubled and these products were dispersed in soil and water. Many cases of contamination of tropical aquatic ecosystems were reported such as the case of diuron in South East Asia, Pacific and Africa for food crops such as pineapple. In parallel, taro (Colocasia esculenta or C. esculenta) large-scale cultivation is well established and the C. esculenta tubers consumption falls within local culinary uses. Here we propose a nature-based solution to mitigate the impact of diuron herbicide on tropical aquatic ecosystem. The aim of this perspective article is to illustrate the ability of cultivated plant C. esculenta to phytoaccumulate diuron pollutant by rhizofiltration. The resulting C. esculenta underwent several treatment steps to be suitable for precise diuron quantification. Analyses showed that the heart of the tubers contained less diuron than the recommended European standards and thus, could be still edible by local population which confirms the compatibility of the uses.

The production of bio-based mineral acids, using hydrochloric acid as a model, was revisited here. Simple, affordable, renewable and non-hazardous reactants-namely sodium chloride and oxalic acid-enabled the preparation of concentrated solutions of hydrochloric acid (6 N) in good yields and in mild conditions, including at pilot scale. The process was easily implemented by mixing the two reactants in refluxing water, followed by azeotropic distillation of the reaction mixture. This approach was extended to other mineral acids such as HBr, HI and HNO3, using the corresponding sodium salt. The described process was compared with current industrial methods for HCl production, highlighting its efficiency, improved safety through the elimination of hazardous substances such as chlorine or concentrated sulfuric acid and its precursors, and enhanced sustainability through reduced of energy consumption and the exclusive use of bio-based reactants. This process exemplifies how green chemistry can contribute to cleaner production by addressing both environmental and sustainability challenges.

Cu-based ecocatalyst for CO 2 electroreduction.

Le dernier rapport de l’IPBES a clairement montré que la pollution et la multiplication des espèces exotiques envahissantes constituaient deux des cinq facteurs majeurs responsables du déclin de la biodiversité. Face à cette situation, nous présentons dans cette brève revue le développement de solutions fondées sur la nature pour répondre à ces deux défis. Cette approche a tout d’abord permis de progresser dans la compréhension des stratégies d’adaptation des plantes et des microorganismes associés, pour répondre à des agressions telles que celle de la pollution. Ainsi, il a pu être démontré que certaines espèces végétales sont capables de se développer dans des milieux contaminés par des éléments métalliques, voire de séquestrer les polluants toxiques dans leurs feuilles ou leurs racines. Ces recherches ont permis d’apporter des solutions originales pour la restauration écologique des sols et la décontamination des systèmes aquatiques à l’aide d’espèces végétales exotiques envahissantes mortes. Afin de les rendre pérennes et économiquement viables, ces solutions ont été valorisées à travers le concept de l’écocatalyse, à l’interface de l’écologie et de la chimie.

Substituted cyclohexenones are well-known building blocks for the synthesis of numerous natural products and bioactive compounds. Despite their widespread use, they are prepared under conditions that are not compatible with the principles of green chemistry. Here the synthesis of substituted cyclohexenones was revisited using a tandem annulation-decarboxylation strategy, in an eco-friendly process without compromising on efficiency. To meet this challenge, environmental catalysts, named ecocatalysts (R), which derived from biomass wastes were used. Under microwave activation, ecocatalysis assisted by statistical tools led to excellent yields, as well as remarkable green metrics for the whole synthetic process, which both exceeded those previously reported. The reaction was scaled-up allowing the recycling assessment of the best ecocatalysts (R). The reaction was also extended to other substrates. The catalytically active species within the best ecocatalyst (R) was identified through extensive characterisation by MP-AES, XRPD, SEM, XPS and solid-state NMR, allowing to depict a mechanism confirmed by DFT calculations.

The latest IPBES report clearly showed that pollution and proliferation of invasive alien species constituted two of the five major factors responsible for the biodiversity decline. Faced with this situation, we present here the development of nature-based solutions in response to these two challenges. This approach has firstly made it possible to progress in understanding the adaptation strategies of plants and associated micro-organisms to respond to attacks such as pollution. Thus, relevant studies showed that certain plant species are able to grow in environments contaminated with metallic elements, or even to sequester toxic pollutants in their leaves or their roots. This research has made it possible to provide original solutions for the ecological restoration of soils and the decontamination of aquatic systems using dead invasive exotic plant species. The promotion of these solutions through the concept of ecocatalysis, at the interface of ecology and chemistry, contributed to make them sustainable and economically viable.

A new generation of ecocatalysts (R) (R) derived from Invasive Alien Species (IAS) ( Fallopia japonica and Arundo donax) ) was used as starting material for the preparation of novel biosourced catalysts. The preparation of these ecocatalysts (R) (R) is a new way to support the management of IAS. These catalysts were characterized by microwave plasma atomic emission spectrometry (MP-AES) and X-ray powder diffraction (XRPD), which revealed basic properties. After calculating Pearson's correlations to evaluate the relative importance of reaction parameters, a design of experiments (DoE) was implemented to synthesize glyceryl caprylate and oleate with a high selectivity. These molecules constitute emollients and non-ionic emulsifiers of high industrial interest. The ecocatalysts (R) (R) were efficient and recyclable for the transesterification of methyl and ethyl fatty esters, leading to high yields (66-83%). These ecocatalysts (R) (R) are an alternative to usual base catalysts previously reported for the transesterification of methyl caprylate, methyl oleate and ethyl caprylate with glycerol, which are often non- recyclable, not systematically selective and require questionable preparation conditions.

Among the causes of disruption of aquatic ecosystems, pollution and the development of invasive alien species are factors of concern. This chapter presents natural solutions for preserving water resources in the light of such problems through an interdisciplinary approach combining: (1) strong and sustainable support in the management of invasive alien aquatic plants; (2) early depollution of industrial effluents using biosorbent plant filters; (3) a solution to avoid the formation of undesirable industrial sludges; and (4) chemical and economic valorization of the phytotechnologies implemented.

p-Menthane-3,8-diol (PMD) is gradually dethroning the synthetic golden standard mosquito repellent, N,N-diethyl-m-toluamide (DEET), as PMD is natural and considered safer while displaying an excellent repellent activity. In this study, we revisited the synthetic route of PMD from citronellal in greener conditions, while maintaining the highest yield, and developed a sustainable post-reaction process. Biosourced ammonium salts were tested to catalyze the carbonyl-ene reaction-hydration transforming citronellal and essential oils rich in citronellal into PMD. Ammonium salts led to excellent conversions and selectivities toward PMD, better than previously reported, even at low catalytic loading and rapidly. Catalytic solution of ammonium salts could be directly reused, up to six times without any loss of activity. The sustainability of the methodology was evaluated using a holistic approach which gave excellent green metrics, such as the PMI (6), TON (708), TOF (17), and E-factor (0.68) in comparison to other processes. The repellent activities of PMD synthesized from citronellal and from essential oils were evaluated against Aedes albopictus, the most invasive mosquito in the world, and were as much or even more repellent than pure PMD.

Persistent and emerging organic pollutants represent a serious and global threat to human health and ecosystems. We describe here a simple, efficient and affordable technology for removing such organic pollutants from aquatic systems. Biosorption process was chosen, meeting these three criteria, and so that biosorbents should be biomass wastes combining the following characteristics: natural, cheap and abundant. Powdered dead roots from invasive alien species (Eichhornia crassipes, Pistia stratiotes and Fallopia japonica), and wastes rich in tannins such as coffee grounds and green tea grounds were tested as biosorbents for removing extensively used organic pollutants: organic UV-filters, insecticides and herbicides. The elemental composition and morphology of the biosorbents were fully determined. The biosorption kinetics for each pair of biosorbent/pollutant was described by a pseudo-second order model. Excellent biosorption efficiency was obtained for 10 μM solution of oxybenzone (89 ± 1%), octocrylene (90 ± 2%), lindane (88 ± 0%) and diuron (90 ± 1%) in only 2 h. And total removal of 10 μM of chlordecone (100 ± 0%) could be achieved, which could be of high concern for the population living in chlordecone-contaminated areas. As such pollutants can be found in aquatic ecosystems, an interference study with salts showed that biosorption efficiency remained as efficient in reconstituted seawater. A principal component analysis was performed as an attempt to rationalise the biosorption results. The solubility of the organic pollutants in water and the concentration of tanins in the biosorbents were key parameters.