CITRATE PERHYDRATES AND THEIR USES

Description

[0001] The invention relates to perhydrate citrates, as well as the uses of perhydrate citrates, particularly as biocides, especially pesticides, more particularly phytopharmaceuticals.

[0002] The invention also relates to a process for preparing these new bio-based organic molecules, which are in the form of a stable, soluble crystalline powder and which contain at physiological pH a new solid form of hydrogen peroxide.

[0003] Biocides refers to a broad family of chemical substances which includes pesticides, in particular plant protection products, and antimicrobials for medical, veterinary, domestic or industrial use, as well as disinfectants for fluids and surfaces, in particular water, air, soil, swimming pools, work surfaces, toilets, etc.

[0004] Antimicrobials and disinfectants can minimize the risk of infection in humans and animals. Since certain bacteria, molds, yeasts, and viruses can lead to serious illnesses, disinfection is a crucial part of daily life, especially in the medical field and in homes. The importance of disinfection for human well-being is often underestimated. In previous centuries, more people died from major epidemics (plague, cholera, smallpox, or influenza) than from wars. Until the early 20th century, severe bacterial infections were often fatal even in industrialized countries. In less developed countries, infectious diseases, most of which stem from inadequate hygiene, still cause numerous deaths today.There is therefore a strong demand for effective and inexpensive antimicrobials and disinfectants, particularly in the medical sector.

[0005] This demand also exists in the agricultural sector for pesticides, particularly fungicides. Indeed, pesticides such as fungicides, insecticides, and herbicides are important auxiliary agents for agriculture, protecting and increasing crop yields. Agricultural personnel work to optimize production by maximizing growing conditions while minimizing pest attacks on seeds, seedlings, plants, and fruits. Such pests include bacteria, fungi, and others. Considerable attention has been paid to antimicrobial compounds that attack bacteria and fungi on seeds, seedlings, growing plants, and fruits. The use of fungicides in agriculture is necessitated by the losses caused by a wide variety of plant pathogenic microorganisms.To be economical, the costs of controlling plant diseases through the application of bactericides and fungicides must be offset by significantly greater potential gains. Large tonnages of fungicides are required in the cultivation of apples, pears, bananas, cereals, cocoa, coffee, cotton, potatoes, tobacco, table and wine grapes, and other common fruits and vegetables such as celery, leeks, onions, lettuce, potatoes, garlic, shallots, peppers, beans, tomatoes, almonds, peanuts, and many others.

[0006] In particular, according to 2016 figures, the global market for plant protection fungicides is estimated at over 9.7 billion euros, including 3.9 billion euros in Europe and 3.6 billion euros in America.

[0007] Within this market, there is strong demand for fungicides in the wine sector. For example, in France, the total consumption of fungicide products for treating vines is estimated at €400 million for a total area of ​​792,000 hectares.

[0008] Conventional biocides are often toxic, carcinogenic, mutagenic, teratogenic, expensive, and / or ineffective. Furthermore, to achieve a powerful disinfectant effect, highly persistent chemicals have been used in the past as disinfectants to provide effective and long-lasting protection against microorganisms. However, this persistence leads to significant environmental problems. Indeed, highly persistent biocides accumulate in groundwater and / or the food chain, causing major ecological and health issues. For example, ecological problems can arise when high concentrations of biocides reach biological wastewater treatment plants. In the case of high biocide concentrations, the microorganisms necessary for the treatment process are affected in their growth, which can lead to partial or complete failure of the wastewater treatment plant.Furthermore, persistent composites can accumulate in sewage sludge.

[0009] To overcome the health and environmental drawbacks of conventional persistent biocides, the use of less hazardous substances has been considered in the past, particularly natural substances with potential disinfectant properties. However, their improved environmental compatibility has come at the expense of their effectiveness and protective capacity against microorganisms. Because of this drawback, less emphasis has been placed on these environmentally friendly disinfectants, and the use of environmentally hazardous compounds has become prevalent.

[0010] Peracetic acid is a powerful oxidizing agent known for its virucidal, bactericidal, fungicidal, and algicidal properties. It was patented in the 1950s for the treatment of plant tissues, particularly those intended for processing, especially fruits and vegetables, to reduce spoilage by bacteria and fungi (US patent 2,522,640). Today, peracetic acid is commonly used in food processing and handling as a disinfectant for food contact surfaces, as well as for fruits, vegetables, meat, and eggs. In fruit and vegetable production, aqueous peracetic acid solutions have been suggested for controlling pathogenic organisms on growing plants.However, one of the major problems associated with liquid aqueous peracetic acid solutions is that these solutions are corrosive, highly acidic, very reactive, and strongly odorous, making their use difficult and dangerous, both for users and for treated plants.

[0011] New, zero-residue, bio-based compounds of the citrate perhydrate type, which are the subject of this application, have now been developed. These compounds release active agents, namely hydrogen peroxide and citrates, which can act synergistically. They have an efficacy equivalent to reference biocides and are all classified as GRAS (Generally Recognized As Safe) by the Food and Drug Administration. Indeed, the degradation products of the citrate perhydrates of the invention are food additives such as, for example, sodium citrates (E331), potassium citrates, zinc citrates, etc.

[0012] Furthermore, the compounds of the invention can be in powder form, which can be easily synthesized using an economical process, packaged, transported, and handled. These powders are physically and chemically stable, meaning that there is no significant change over time (for example, after one year at room temperature, i.e., at a temperature between 20 and 25°C) in their physical state and chemical composition, particularly their active oxygen concentration. They are also odorless, highly soluble in water, and the corresponding aqueous solutions have a wide pH range, between 4 and 8. Indeed, the pH obtained by dissolving other compounds containing hydrogen peroxide (for example, a pH of 11 for sodium percarbonate) may not be suitable for plant treatment.These compounds are easy to implement, in particular because they eliminate the need for concentrated hydrogen peroxide solutions, which are well known to be oxidizing, irritating and likely to cause a fire or explosion.

[0013] Furthermore, these compounds allow for easy application and safe handling. In addition, upon drying, these solutions form a protective antimicrobial biofilm, making the treated surface more resistant, particularly to bacterial and / or fungal contamination.

[0014] Quite surprisingly, the perhydrate citrates of the invention are physically and chemically stable. In contrast, concentrated solutions of citric acid and hydrogen peroxide, when mixed, do not crystallize as perhydrates and are not chemically stable, particularly with regard to the concentration of active oxygen. The compounds of the invention therefore make it possible to stabilize solid concentrated hydrogen peroxide in the form of new perhydrate citrate molecules.

[0015] For example, a solution containing 37.5% hydrogen peroxide and 25% citric acid loses an average of 34.4% of its hydrogen peroxide content after 20 days. This instability results from the oxidation of citric acid by hydrogen peroxide to dicarboxylic acetone, which is in turn oxidized to formaldehyde, formic acid, and carbon dioxide. A second epoxidation of citric acid also occurs, leading to the formation of percitric acid (example 7).

[0016] Thus, according to a first aspect, the invention relates to an alkali metal perhydrate citrate, the perhydrate citrate is a disodium perhydrate citrate, in particular an anhydrous disodium monoperhydrate citrate.

[0017] According to one embodiment, alkali metal citrate perhydrate is in the form of a crystal consisting of alkali metal citrate, hydrogen peroxide, and optionally water.

[0018] According to one embodiment, said citrate perhydrate is in the form of a hydrate, in particular a monohydrate or a dihydrate.

[0019] According to one embodiment, said citrate perhydrate is a citrate monoperhydrate or a citrate diperhydrate, in particular a citrate monoperhydrate.

[0020] According to a particular embodiment, said citrate perhydrate is a disodium citrate monoperhydrate co-crystallised with urea perhydrate.

[0021] According to a particular embodiment, said citrate perhydrate is a non-hydrated disodium citrate perhydrate.

[0022] The hydrates of the invention are advantageously easily soluble in water, particularly at 25°C, their solubility being in particular greater than or equal to 850 g / l at 25°C.

[0023] In one embodiment, the citrate perhydrate is in the form of a crystal, in particular a crystalline hydrate. In another embodiment, the citrate perhydrate is used in the absence of N-acyl compounds intended to acylate the hydrogen peroxide.

[0024] According to one embodiment, said citrate perhydrate is used in the presence of urea perhydrate.

[0025] According to a particular embodiment, said citrate perhydrate is co-crystallised with urea perhydrate.

[0026] According to an advantageous embodiment, said citrate perhydrate is used in the presence of urea perhydrate in crystal form, these two crystals being in particular in the form of co-crystals.

[0027] According to an advantageous embodiment, said citrate perhydrate is a disodium citrate perhydrate co-crystallized with urea perhydrate.

[0028] In particular, urea perhydrate is in the form of a urea-hydrogen peroxide cocrystal. The combined use of urea perhydrate has the advantage of providing a nitrogen source while increasing the hydrogen peroxide concentration. In one embodiment, said citrate perhydrate is used in the presence of water.

[0029] According to one embodiment, said citrate perhydrate is used in the presence of at least one additional compound selected from anti-caking agents, surfactants, in particular biosurfactants, wetting agents, anti-foaming agents, anti-drift agents, thickeners, foaming agents, fertilizers, plant protection products, stabilizers and mixtures thereof, the additional compound being selected in particular from glycolipids, disodium pyrophosphate, sodium cocoyl isethionate, heptamethyltrisiloxane, disodium silicate, zinc oxides or peroxides and silicon dioxide.

[0030] According to a particular embodiment, said citrate perhydrate is used in a mixture with water and optionally at least one additional compound selected from anti-caking agents, surfactants, in particular biosurfactants, wetting agents, antifoaming agents, anti-drift agents, thickeners, foaming agents, solidifying agents, fertilizers, plant protection products, stabilizers and mixtures thereof, the additional compound being selected in particular from glycolipids, disodium pyrophosphate, sodium cocoyl isethionate, heptamethyltrisiloxane, disodium silicate, zinc oxides or peroxides and silicon dioxide, the percentage by weight of said alkali, alkaline earth, transition or poor metal citrate perhydrate relative to the total weight of said mixture being in particular from 0.05 to 5%.

[0031] More specifically, the percentage by weight of said citrate perhydrate relative to the total weight of said mixture is from 0.1 to 2, 2.5, 3, 3.5, 4 or 4.5%.

[0032] Such additional compounds are well known to those skilled in the art. They can be preformulated as a mixture with citrate perhydrate, or added to the mixture obtained by contacting citrate perhydrate with water.

[0033] According to a particular embodiment, said at least one additional compound is selected from the group comprising urea citrate, a co-crystal of citric acid and urea, optionally perhydrated, and urea perhydrate, particularly in crystalline form. The compounds in this group allow, in particular, the adjustment of pH and / or the adjustment of hydrogen peroxide concentration and / or the adjustment of nitrogen supply when using the perhydrate citrates of the invention.

[0034] When the compound of the invention is used in the presence of a compound comprising magnesium, these compounds are further used as fertilizers, in particular foliar fertilizers, or as amendments.

[0035] Stabilizers include peroxide stabilizers. These stabilizers are well known to those skilled in the art, particularly as hydrogen peroxide stabilizers.

[0036] The addition of a foaming agent can produce a mixture according to the invention in the form of a foam. These foams can be used on surfaces.

[0037] The addition of a thickener can produce a mixture according to the invention in the form of a gel. These gels can be used on the skin of humans or animals, particularly the hands.

[0038] The addition of a solidifying agent can produce a mixture according to the invention in solid form. These solids can be used to treat water, particularly in swimming pools and toilets.

[0039] According to an advantageous embodiment, said additional compound is selected from glycolipids, in particular rhamnolipids.

[0040] These rhamnolipids can be obtained using techniques well known to those skilled in the art, particularly by culturing bacteria of the genus Pseudomonas in the presence of molasses.

[0041] Within the compositions of the present invention, glycolipids, in particular rhamnolipids, possess advantageous eliciting and biosurfactant properties.

[0042] In another aspect, the invention relates to the use of a citrate perhydrate according to the invention as a biocide. According to one embodiment, the use as defined above is a use to inhibit the growth of a pathogen on or in a plant.

[0043] Thus, the present invention also relates to the use of a compound as described above or of a composition as described above as an inhibitor of the growth of a pathogen on or in a plant.

[0044] Without wanting to limit ourselves to any particular theory, the aforementioned citrate perhydrate causes oxidative, ionic, and osmotic stress to the targeted pathogen and leads to the constriction of its cellular contents in the case, for example, of the pathogen Erysiphe slayer, as illustrated in the figure 7 .

[0045] According to one embodiment, the use as defined above is a use to prevent the growth of a pathogen on or in a plant.

[0046] The present invention relates to the use of a compound as described above or of a composition as described above in the prevention of the growth of a pathogen on or in a plant.

[0047] Without wanting to limit ourselves to any particular theory, prevention is achieved through the sticky properties attributed to citrates and / or any added sticky agents, which results in the formation of a protective barrier around the treated surface, preventing, for example, the spread of spores.

[0048] In particular, said citrate perhydrate is applied to the surface of the plant, in particular at a rate of 25 to 1000 ng.dm -2.

[0049] According to one embodiment, said citrate perhydrate, possibly used in the presence of water, is applied to the surface of the plant by spraying, vaporizing, soaking, brushing, fumigating or electrostatic spraying, preferably by spraying, in particular by foliar spraying.

[0050] In one embodiment, the citrate perhydrate, optionally used in the absence of water, is applied to the plant roots or to the soil in contact with the plant roots. In another embodiment, the pathogen is selected from viruses, bacteria, fungi, and pseudofungi.

[0051] According to a particular embodiment, the pathogen is a fungus or a pseudofungus selected from Albugo spp., Alternaria spp., Armillaria spp., Aspergillus spp., Athelia spp., Bipolaris spp., Botryosphaeria spp., Botryotinia spp., Botrytis spp., Bremia spp., Candida spp., Capnodium spp., Ceratobasidium spp., Ceratocystis spp., Cercospora spp., Choanephora spp., Claviceps spp., Corynespora spp., Cronartium spp., Cryphonectria spp., Cylindrocladium spp., Cytospora spp., Diaporthe spp., Diplodia spp., Dreschlera spp., Elsinoe spp., Erexohilum spp., Erysiphe spp., Eutypa spp., Exobasidium spp., Fusarium spp., Gaeumannomyces spp., Gliocladium spp., Gymnosporangium spp., Heterobasidium spp., Hypoxylon spp., Kutilakesa spp., Lophiodermium spp., Magnaporthe spp., Melampsora spp., Monilinia spp., Mycosphaerella spp., Myrothecia spp., Nectriella spp., Nematospora spp., Oïdium spp., Olpidium spp., Ophiostoma spp., Penicillium spp., Peronospora spp., Phakospora spp., Phoma spp., Phomopsis spp., Phragmidium spp., Phyllactinia spp., Physoderma spp., Phytophthora spp., Plasmodiophora spp., Plasmopara spp., Pseudoperonospora spp., Puccinia spp., Pythium spp., Rhizoctonia spp., Rhizopus spp., Rhytisma spp., Sclerotinia spp., Sclerotium spp., Spongospora spp., Synchytrium spp., Taphrina spp., Thanatephorus spp., Thielaviopsis spp., Tilletia spp., Uncinula spp., Urocystis spp., Ustilago spp., Valsa spp., Venturia spp., Verticillium spp., Xylaria spp., Fomitiporia spp., Stereum spp., Phaeoacremonium spp. And Phaeomoniella spp.

[0052] According to an even more specific embodiment, the pathogen is a fungus or a pseudofungus selected from Plasmopara spp., Erysiphe spp., Botrytis spp., Aspergillus spp.And Candida spp.

[0053] According to a particular embodiment, the pathogen is a bacterium selected from bacteria of the genus Pseudomonas, Escherichia, Staphylococcus, Enterococcus, And Legionella.

[0054] According to a particular embodiment, the pathogen is one or more microorganisms selected from Candidatus phytoplasma, Fomitiporia punctata, F. mediteranea, Stereum hirsutum, Phaeoacremonium aleophilium, Phaeomoniella chlamydospora, Botryosphaeria obtusa, Botryosphaeria dothidea parva and stevensii, And Eutype broad.

[0055] According to one embodiment, the plant is chosen from among fruit-producing plants, vegetable-producing plants, ornamental plants, turf and cereals.

[0056] An ornamental plant is understood to be, in particular, a plant cultivated for its aesthetic qualities.

[0057] The term "lawn" refers in particular to all fine grasses, especially grasses, that constitute or are included in lawns.

[0058] According to a particular embodiment, the plant produces fruits selected from apple, apricot, banana, blackberry, blueberry, cherry, cranberry, currant, table grape, wine grape (the plant being in particular the vine), pomegranate, gooseberry, melon, lemon, mandarin, melon, orange, peach, pear, pineapple, plum, raspberry, strawberry, tomato, watermelon, grapefruit, pepper, olive, lime, almond, walnut, Brazil nut, cashew nut, chestnut, hazelnut, macadamia nut, pecan nut and pistachio.

[0059] According to a particular embodiment, the plant produces vegetables selected from artichoke, beans, beetroot, broccoli, cabbage, carrot, cauliflower, celery, chicory, chives, cress, cucumber, kale, eggplant, kohlrabi, lettuce, onion, pepper, parsnip, parsley, pea, potato, pumpkin, radish, shallot, soybean, spinach, turnips and peanuts.

[0060] According to a particular embodiment, the plant is a cereal, especially in the form of stubble.

[0061] According to a particular embodiment, the plant is a cereal chosen from amaranth, barley, buckwheat, fonio, kamut (Khorasan wheat), millet, oats, quinoa, rice, rye, sorghum, spelt, triticale, wheat, or rapeseed.

[0062] According to one embodiment, the present invention also relates to the use of a compound as described above or of a composition as described above as a biocontrol element.

[0063] According to one embodiment, the present invention relates to the use of a perhydrate citrate to disinfect a fluid or a surface, in particular water, air, soils, swimming pools, work surfaces, toilets.

[0064] According to one embodiment, the present invention relates to the use of citrate perhydrate for disinfecting a fluid, in particular water or air, by reducing the number of viable bacterial cells, the bacterial cells being in particular of the genus Legionella, more specifically L. pneumophila.

[0065] Thus, the said citrate perhydrate can be used as a disinfectant for a fluid or a surface.

[0066] Facilities such as spas, swimming pools, cooling towers, food production facilities, and hospital environments are likely to be disinfected by a compound as described above or a composition as described above.

[0067] According to another embodiment, the present invention relates to the use of a perhydrate citrate to disinfect a surface, particularly in communities, in hospital settings or in agri-food production facilities, especially floors, work surfaces, toilets.

[0068] According to one embodiment, the present invention relates to the use of citrate perhydrate to disinfect a surface, notably by reducing the number of viable bacterial cells or fungi, the bacterial cells being in particular selected from Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Enterococcus hirae, and the mushrooms being specifically selected from Candida albicans And Aspergillus niger.

[0069] According to one embodiment, the present invention relates to the use of a citrate perhydrate as defined above, as an elicitor.

[0070] According to one embodiment, the present invention relates to a citrate perhydrate for its non-therapeutic use as an antimicrobial in humans or animals.

[0071] It should be noted that all the embodiments mentioned above with regard to citrate perhydrate also apply here, alone or in combination.

[0072] According to a particular embodiment, citrate perhydrate is used in dentistry.

[0073] According to another particular embodiment, citrate perhydrate is used in animals, especially for the treatment of udders, particularly in cows, or feet, particularly in horses.

[0074] According to another aspect, the present invention relates to a method of teeth whitening by bringing the teeth into contact with a citrate perhydrate.

[0075] According to another aspect, the present invention provides a citrate perhydrate as previously described, for its use in dentistry, particularly in teeth whitening.

[0076] It should be noted that all the embodiments mentioned above with regard to citrate perhydrate also apply here, alone or in combination.

[0077] According to one embodiment, the present invention relates to a citrate perhydrate for use as a bactericide or bacteriostatic agent, particularly against selected bacteria from Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Enterococcus hirae.

[0078] According to one embodiment, said use is by topical route.

[0079] According to another aspect, the present invention relates to a pharmaceutical composition consisting of or comprising a citrate perhydrate and a pharmaceutically acceptable excipient.

[0080] It should be noted that all the embodiments mentioned above with regard to citrate perhydrate also apply here, alone or in combination.

[0081] According to the invention, alkali metal citrate perhydrate is a disodium citrate monoperhydrate.

[0082] According to one embodiment, alkali metal citrate perhydrate is in the form of a crystal consisting of citric acid and / or alkali metal citrate, hydrogen peroxide, and optionally water.

[0083] According to one embodiment, the alkali metal perhydrate citrate is in the form of a hydrate.

[0084] The perhydrate citrates of the invention can be unique crystals. Indeed, the signature obtained by X-ray diffraction measurement is specific to them. These crystals are distinguished in particular by the number and nature of the alkali metals, by the number of hydrogen peroxide molecule adducts, and by the number of water molecule adducts.

[0085] According to one embodiment, alkali metal perhydrate citrate is a disodium perhydrate citrate exhibiting an X-ray diffraction spectrum with the following characteristic lines at angles 2Θ (in °), in particular the characteristic lines whose relative intensity is greater than or equal to 15: Pictures 2Θ Relative intensity Index hkl 1 7,10442 2,42 0 1 1 2 6,53808 6,93 1 1 1 3 6,19763 11,5 0 2 0 4 5,03008 18,94 2 2 0 5 4,83206 0,76 1 2 1 6 4,45527 10,07 3 1 1 7 4,34762 32,9 2 2 1 8 4,29193 11,19 4 0 0 9 4,21333 17,21 3 2 0 10 3,97003 19,47 1 1 2 11 3,85293 13,47 4 0 1 and 2 0 2 12 3,78756 19,04 3 2 1 13 3,67804 12,75 4 1 1 14 3,53769 100 4 2 0 15 3,47303 5,61 1 2 2 16 3,42705 7,44 2 3 1 17 3,32368 6,66 3 1 2 18 3,2801 32,86 2 2 2 19 3,13095 31,11 3 3 1 20 3,09689 19,5 5 1 1

[0086] According to an advantageous embodiment, said citrate perhydrate is a disodium citrate perhydrate co-crystallized with urea perhydrate, in particular a disodium citrate perhydrate co-crystallized with urea perhydrate.

[0087] According to another aspect, the invention also relates to a composition consisting of or comprising citrate perhydrate as defined above and urea perhydrate.

[0088] In particular, urea perhydrate is in the form of a urea-hydrogen peroxide co-crystal.

[0089] According to an advantageous embodiment, the invention relates to a composition comprising crystals of disodium citrate perhydrate and crystals of urea perhydrate, particularly in the form of a urea-hydrogen peroxide co-crystal. The crystals of disodium citrate perhydrate and those of urea perhydrate are, in particular, co-crystallized.

[0090] According to another aspect, the invention relates to a process for preparing an alkali metal perhydrate citrate as defined above, said process comprising: (i) a step of contacting a disodium citrate with hydrogen peroxide, to obtain said alkali metal perhydrate citrate.

[0091] Preferably, the amounts of disodium citrate and hydrogen peroxide are stoichiometric, according to the composition of the desired alkali metal perhydrate citrate.

[0092] Stoichiometric quantities are implemented, for example, using a gravimetric doser.

[0093] According to an advantageous embodiment, disodium citrate is in solid form, particularly anhydrous, and hydrogen peroxide is in the form of an aqueous solution of hydrogen peroxide at a concentration of 30 to 80% by weight.

[0094] Step (i) is carried out in particular at a temperature of 30 to 90°C, in particular 40 to 80°C, more particularly 50 to 70°C, in particular 55 to 65°C.

[0095] According to a very advantageous embodiment, the contact is made by means of an extruder, for example a twin-screw extruder.

[0096] According to another advantageous embodiment, the composition obtained in step (i) is admitted into an alcohol or an alcoholic solution, said alcohol being in particular a C1 to C5 alcohol. The use of this alcohol can in particular allow the precipitation of the desired citrate perhydrate, which can be isolated by well-known liquid / solid separation techniques.

[0097] According to a very advantageous embodiment, the contact is made by mixing an aqueous solution containing disodium citrate and hydrogen peroxide; and alcohol or alcoholic solution, the volume ratio of alcohol or alcoholic solution to aqueous solution being in particular between 3.7:1 and 8:1.

[0098] According to one embodiment, step (i) is preceded by a step of neutralizing citric acid with sodium hydroxide, carbonate or citrate, in order to obtain disodium citrate as mentioned in step (i).

[0099] This neutralization step can be total or partial.

[0100] According to another embodiment, a step of neutralizing citric acid with sodium hydroxide, carbonate or citrate, in order to obtain disodium citrate as mentioned in step (i), is carried out concurrently with this step (i).

[0101] In particular, the invention relates to a process for preparing an alkali metal perhydrate citrate as defined above, said process comprising: (i') a step of contacting citric acid; a sodium hydroxide, carbonate or citrate; and hydrogen peroxide, to obtain said alkali metal perhydrate citrate. Sodium hydroxide, carbonate, or citrate is notably a sodium citrate

[0102] Preferably, the amounts of citric acid / citrate, alkali metal, and hydrogen peroxide are stoichiometric, according to the composition of the desired alkali metal perhydrate citrate.

[0103] According to a particular embodiment, step (i) or (i') as defined above is followed by a drying and / or grinding step.

[0104] These steps can be carried out using techniques well known to those skilled in the art.

[0105] According to another aspect, the invention relates to a method for preparing a composition consisting of or comprising a citrate perhydrate according to the invention, and urea perhydrate, as defined above, said method comprising a step (a) of co-crystallization by contacting a disodium citrate; urea; and hydrogen peroxide.

[0106] Preferably, the amounts of disodium citrate and hydrogen peroxide are stoichiometric, according to the composition of the desired alkali metal perhydrate citrate.

[0107] Preferably, the amount of urea is from 1 to 5 moles of urea per mole of citric acid salt, preferably from 2 to 4 moles of urea per mole of citric acid salt, in particular from 3 moles of urea per mole of citric acid salt. According to an advantageous embodiment, the disodium citrate and urea are in solid form, and the hydrogen peroxide is in the form of an aqueous solution of hydrogen peroxide at a concentration of 30 to 80% by weight.

[0108] Step (a) is carried out in particular at a temperature of 30 to 90°C, in particular 40 to 80°C, more particularly 50 to 70°C, in particular 55 to 65°C.

[0109] According to a very advantageous embodiment, the contact is made by means of an extruder, for example a twin-screw extruder.

[0110] According to one embodiment, step (a) is preceded by a step of neutralizing citric acid with sodium hydroxide, carbonate or citrate, in order to obtain disodium citrate as mentioned in step (a).

[0111] This neutralization step can be total or partial.

[0112] According to another embodiment, a step of neutralizing citric acid with sodium hydroxide, carbonate or citrate, in order to obtain disodium citrate as mentioned in step (a), is carried out concurrently with this step (a).

[0113] In particular, the invention relates to a process for preparing a composition consisting of or comprising citrate perhydrate as defined above, and urea perhydrate, as defined above, said process comprising: (a') a step of contacting citric acid; sodium hydroxide, carbonate or citrate; urea; and hydrogen peroxide, to obtain said alkali metal citrate perhydrate.

[0114] Sodium hydroxide carbonate or sodium citrate is notably a sodium citrate.

[0115] Preferably, the amounts of sodium citrate and hydrogen peroxide are stoichiometric, according to the composition of the desired alkali metal perhydrate citrate.

[0116] Preferably, the amount of urea is between 1 and 5 moles of urea per mole of citric acid salt, preferably between 2 and 4 moles of urea per mole of citric acid salt, and in particular 3 moles of urea per mole of citric acid salt.

[0117] According to a particular embodiment, step (a) or (a') as defined above is followed by a drying and / or grinding step.

[0118] These steps can be carried out using techniques well known to those skilled in the art. Definitions

[0119] As used in this description, the term "approximately" refers to a range of values ​​within ±10% of a specific value. For example, the expression "approximately 120 mg" includes values ​​within 120 mg ±10%, that is, values ​​from 108 mg to 132 mg.

[0120] For the purposes of this description, percentages refer to percentages by weight relative to the total weight of the formulation, unless otherwise stated.

[0121] As understood here, value ranges in the form of "xy," "from x to y," or "between x and y" include the bounds x and y as well as the integers between them. For example, "1-5," "from 1 to 5," or "between 1 and 5" denotes the integers 1, 2, 3, 4, and 5. Preferred embodiments include each integer individually within the value range, as well as any subcombination of these integers. For example, preferred values ​​for "1-5" might include the integers 1, 2, 3, 4, 5, 1-2, 1-3, 1-4, 1-5, 2-3, 2-4, 2-5, and so on.

[0122] By "citrate" is meant a salt of citric acid, that is to say, at least one of the three carboxylic acid groups of citric acid, in particular two of the three or all three carboxylic acid groups of citric acid, is in salt form, in particular as an alkali, alkaline earth, transition or poor salt.

[0123] Examples of salts include salts with alkali metals (sodium, potassium, lithium), with alkaline earth metals (magnesium, calcium), with transition metals, with low-grade metals (zinc), ammonium salt, urea salt, nitrogenous base salts (ethanolamine, diethanolamine, trimethylamine, triethylamine, methylamine, propylamine, diisopropylamine, NN-dimethylethanolamine, benzylamine, dicyclohexylamine, N-benzyl-p-phenethylamine, NN'-dibenzylethylenediamine, diphenylenediamine, benzhydrylamine, quinine, chlorine, arginine, lysine, leucine, dibenzylamine).

[0124] The term "citrate perhydrate" (or citrate perhydrate, or citrate peroxyhydrate, or citrate peroxyhydrate, or citrate peroxosolvate, these terms being equivalent here) refers in particular to an adduct between a citrate and hydrogen peroxide, the citrate and hydrogen peroxide being linked, more specifically, within the same solid, and even more specifically within the same crystal, by hydrogen bonds. Thus, preferably, the term "citrate perhydrate" does not refer to a percitrate that may be hydrated.

[0125] Thus, a citrate perhydrate has, in particular, the following formula (I): in which x is strictly greater than 0, x being in particular 1 or 2, and M 1 , M 2 and M 3 independently represent H or an atom or compound capable of forming a salt with a carboxylic acid group, in particular an alkali, alkaline earth, transition or poor metal, in particular an alkali metal, at least one of M 1 , M 2 and M 3 not representing H. It is to be noted that this formula (I) can be combined with any other definition or embodiment above.

[0126] A "poor metal" is defined as a metallic chemical element located in the periodic table between the transition metals to their left and the metalloids to their right. Zinc is an example of a poor metal.

[0127] In particular, only one of the groups M1, M2 and M3 represents H. If for example M=Na, we speak of disodic.

[0128] In particular, none of the groups M1, M2 and M3 represent H. If for example M=Na, we speak of trisodic.

[0129] In particular, two of the groups M1, M2 and M3 represent H. If for example M=Na, we speak of monosodic.

[0130] When M 1 , M 2 and / or M 3 represent an alkaline earth, transition or poor metal, this metal may also be linked to another carboxylate, present on the same citrate or on another citrate of formula (I).

[0131] For example, one of M1, M2 and M3 represents an alkaline earth metal, the other two being H. In this case, the corresponding citrate of formula (I) is notably of formula (C6H7O7)(alkaline earth metal) ½ .x H2O2.

[0132] By "biocide" we mean pesticides, as well as antimicrobials for medical, veterinary, domestic or industrial use, and disinfectants for fluids and surfaces, in particular water, air, soil, swimming pools, work surfaces, toilets, etc.

[0133] Unless otherwise specified, "surface" includes, in particular, the surfaces of living tissues, especially the surface of plants (e.g., leaf surfaces), and skin (in humans or animals), as well as inert surfaces, including organic or inorganic inert surfaces, e.g., soils and work surfaces.

[0134] In the case of pesticides, the surface area considered is notably that of a plant.

[0135] In the case of antimicrobials, the surface considered is in particular that of the skin, in humans or in animals.

[0136] In the case of disinfectants, the surface in question is notably an inert surface.

[0137] The term "pesticide" refers to a chemical substance that can be used to control organisms considered harmful. It is a generic term encompassing insecticides, fungicides, herbicides, and parasiticides. These substances target, respectively, insect pests, fungi, weeds, and parasitic worms.

[0138] The term "phytopharmaceutical composition" refers to a plant protection product, that is, any product intended to: to protect plants or plant products against all harmful organisms or to prevent their action; to act on the vital processes of plants, provided that it is not a matter of nutrients (for example, growth regulators); to ensure the preservation of plant products; to destroy unwanted plants; and / or to destroy parts of plants, to slow down or prevent unwanted plant growth.

[0139] By "antimicrobial" we mean a substance that kills or slows the growth of microbes such as bacteria, fungi, viruses, or parasites, particularly in humans or animals.

[0140] By "disinfectant" we mean a product that kills or inactivates microorganisms, such as bacteria, viruses and protozoa, on inert surfaces or within fluids such as water and air.

[0141] The term "hydrate" refers to a compound formed, in particular, by the union of citrate perhydrate and water. The hydrate is specifically a crystalline salt. This is then referred to as the water of crystallization.

[0142] By "non-hydrated", we mean a compound devoid of water of crystallization.

[0143] By "biosurfactant" we mean a surfactant synthesized by a living organism.

[0144] By "pseudofungi", we mean organisms chosen in particular from among the Oomycetes, the Hyphochytridiomycetes and the Labyrinthulomycetes.

[0145] By "stubble" we mean a crop residue consisting of the part of the cereal stalks that remains on the ground after harvest.

[0146] An "elicitor" is a compound or composition that triggers plant defense mechanisms, resulting in the production of defensive substances. It is a stimulator of the plant's natural defenses (NDS).

[0147] As used here, the term "pharmaceutically acceptable" refers to compounds, compositions and / or dosage forms that are, within the scope of sound medical judgment, suitable for use in contact with human and lower animal cells without toxicity, irritation, undue allergic response and the like, and are proportionate to a reasonable benefit / risk ratio.

[0148] The terms "sodium, disodium, trisodium citrate" are, throughout this description and unless otherwise stated, interchangeable with the terms "sodium, disodium, trisodium citrate," respectively. The same applies to the other metals.

[0149] The term "co-crystallized" refers specifically to two crystals of different compounds, obtained from a solution, notably by evaporation of that solution, containing these two compounds. At least one of these two compounds may be in the form of a co-crystal.

[0150] Thus, in particular, co-crystallized crystals form a composition where two crystals of different nature coexist, unlike a co-crystal, which is a single crystal comprising or made up of two different compounds. FIGURES

[0151] There figure 1 represents the distribution diagram of citric acid and its salts. figure 2 corresponds to the powder diffraction pattern of trisodium citrate monoperhydrate dihydrate from Example 2 (λ = 1.5418 Å). The figure 3 represents the asymmetric unit and schematic labeling of trisodium citrate monoperhydrate dihydrate from Example 2. The figure 4 corresponds to the powder diffraction pattern of disodium citrate perhydrate from Example 3 (λ = 1.5418 Å). The figure 5 illustrates the diffractogram of the co-crystallization of one mole of disodium citrate perhydrate and three moles of urea perhydrate (λ = 1.5418 Å), according to example 4. The figure 6corresponds to the logarithmic concentration of the different pathogenic strains initially present and the logarithmic decrease in strains after treatment with formulation 3 at a hydrogen peroxide concentration of C1 (= 0.5%) and C2 (= 3%). figure 7 corresponds to microscopic images of the fungus Erysiphe killer. Figure 7A : in water. Figure 7B : in the presence of citrate perhydrate (10 mg / ml). The figure 8 illustrates the results obtained during the evaluation of the effectiveness of formulation 3 of the invention in the field, for the treatment of powdery mildew, according to example 5.5. The percentage of incidence and severity of the disease is recorded, whether on the leaves ( figure 8A ) or on the grapes ( figure 8B ). EXAMPLES Example 1: Synthesis of citrate perhydrates

[0152] One process for preparing perhydrate citrates involves crystallizing hydrogen peroxide with a salt of citric acid.

[0153] The perhydrate citrates that are the subject of the present invention can be produced from the preparation process shown below.

[0154] The equipment that can be used consists of a gravimetric feeder for the raw materials, a twin-screw extruder for the slurry crystallization reaction, followed by a fluidized bed dryer, or a vacuum microwave dryer, and a granulator.

[0155] The raw materials for the process are hydrogen peroxide, in the form of a concentrated aqueous solution of 30 to 80%, and a salt of citric acid. The citric acid salt can, among other methods, be obtained by partial or total neutralization of citric acid with a carbonate, a hydroxide, or one of its own salts, the cations of which are selected from alkali, alkaline earth, transition, or depleted metals suitable for the production of the desired citrate perhydrate of the present invention. The neutralization of the citric acid can, among other methods, be carried out prior to the crystallization reaction by mixing the powders or directly within the extruder by individual injection of each component. Stage 1 : Crystallization reaction

[0156] Using a gravimetric feeder, the raw materials are injected into a twin-screw extruder. The quantity of raw materials injected conforms to the stoichiometry of the desired citrate perhydrate of the present invention. For example, in the case of the preparation of anhydrous disodium citrate monoperhydrate, one possible production method is the crystallization of 2 moles of trisodium citrate and 1 mole of citric acid with 3 moles of hydrogen peroxide.

[0157] The raw materials are mixed within the twin-screw extruder and begin to crystallize at a controlled temperature and residence time to produce a solid at the extruder outlet. For example, in the case of the production of anhydrous disodium citrate monoperhydrate, the crystallization temperature is 55–65°C and the residence time is approximately 1 minute when the solid raw materials used are anhydrous. It should be noted that the use of hydrated solid raw materials requires an extruder equipped with a degassing system, significantly reduces the exothermic nature of the reaction, and can considerably prolong the residence time in the extruder.

[0158] At this stage, the solid obtained at the extrusion output is thixotropic and can be easily shaped, such as into granules for example, without agglomerating.

[0159] To finalize the crystallization of the desired citrate perhydrate of the present invention, the solid obtained at the extruder outlet is cooled by natural convection to 15-25°C. The rejection of excess water during the crystallization reaction is visually observable on the surface of the solid. Step 2 : Drying and grinding

[0160] Once crystallized, citrate perhydrate can be dried at a controlled temperature using a fluidized bed dryer or a vacuum microwave dryer, and then ground to the desired particle size, since the product is no longer thixotropic at this final stage. For example, in the case of producing anhydrous disodium citrate monoperhydrate, the drying temperature is 40–60°C. Variant for the production of a co-crystallized citrate perhydrate with urea perhydrate.

[0161] A citrate perhydrate according to the present invention can be produced by co-crystallization with urea to form a co-crystal of citrate perhydrate and urea perhydrate.

[0162] To achieve this, urea is also injected by gravimetric dosing into the twin-screw extruder. The molar ratios to be respected range from 1 to 5 moles of urea per mole of citric acid salt, preferably 3 moles of urea per mole of citric acid salt.

[0163] The amount of hydrogen peroxide must be adjusted to maintain the stoichiometry of the desired crystals of citrate perhydrate produced according to the present invention and urea perhydrate. For example, in the case of co-crystallizing 1 mole of trisodium citrate monoperhydrate dihydrate and 3 moles of urea perhydrate, 4 moles of hydrogen peroxide crystallize with 1 mole of trisodium citrate and 3 moles of urea.

[0164] This production method offers significant advantages compared to the independent production of urea perhydrate, which would then be mixed in solid form with the produced citrate perhydrates. Indeed, urea perhydrate available on the European market sells for approximately €20 / kg, while urea is sold for less than €1 / kg. Furthermore, independently produced urea perhydrate is generally stabilized by the addition of stabilizers that are more or less toxic, making it incompatible with a bio-based, zero-residue biocide such as the citrate perhydrates of the present invention. In contrast, urea perhydrate produced by co-crystallization with citrate perhydrate is stable without the addition of stabilizers. This is likely due to the presence of citrate as a natural and non-toxic stabilizer. Variant for producing a citrate perhydrate from an alcoholic solution.

[0165] A citrate perhydrate can be obtained by crystallization in alcoholic solution.

[0166] To this end, a first solution is prepared containing the salt of citric acid and hydrogen peroxide in quantities that respect the stoichiometric ratio of the desired citrate perhydrate produced by the present invention. The citric acid salt can, among other methods, be obtained by partial neutralization of citric acid with a carbonate, a hydroxide, or one of its own salts, the cations of which are selected from alkali, alkaline earth, transition, or depleted metals suitable for the production of the desired citrate perhydrate produced by the present invention.

[0167] A second solution is prepared: an alcoholic solution, in which the alcohol contains, in particular, 1 to 5 carbon atoms and which may most specifically be ethanol. This solution may also be the alcohol itself.

[0168] These two solutions are then mixed. The volume ratio of the alcoholic solution is between 3.7:1 and 8:1 relative to the first aqueous solution containing citrate and hydrogen peroxide.

[0169] The perhydrate citrates produced precipitate as crystals and are recovered using liquid / solid separation techniques known to those skilled in the art (filtration, centrifugation, etc.) and are possibly dried at 40-60°C. Example 2 (comparative) : Trisodium citrate monoperhydrate dihydrate

[0170] Trisodium citrate monoperhydrate dihydrate was prepared as shown in Example 1. 2.1. Crystalline structure Materials and methods X-ray diffraction on powder

[0171] The samples were gently ground into a fine powder using a pestle and mortar. Powder X-ray diffraction data were collected using a PANalytical XPERT-PRO diffractometer (Bragg-Brentano geometry, Cu Kα radiation (λ = 1.5418 Å), generator settings: 45 kV and 30 mA). Powder diffraction patterns were measured from 4° to 40° in 2θ, and the measurement time was 6 to 15 minutes. Results

[0172] The resulting diffractogram, presented to the figure 2 , as well as the characteristic lines in Table 1, show an unknown crystalline structure, which differs from the starting product, tri-sodium citrate, and all its hydrated forms: Table 1: Characteristic lines of trisodium citrate monoperhydrate dihydrate Pics 2Θ Relative intensity index hkl 1 9,924509 100 0 0 1 2 8,740994 5,95 0 1 0 and 0 1 -1 3 6,148828 0,87 1 0 0 4 5,519614 15,76 -1 0 1 5 5,483783 36,95 0 -1 2 6 5,372527 51,54 -1 1 0 7 4,959513 16,42 -1 -1 1 and 0 0 2 8 4,871902 5,55 0 -2 1 9 4,740059 4,39 1 1 0 10 4,413263 36,26 -1 1 1 11 4,381867 6,14 0 -2 2 12 4,364081 19,23 0 2 0 13 4,094722 2,37 -1 0 2 14 4,000887 38,77 1 -2 1 and 1 -1 2 15 3,679708 4,92 0 -1 3 16 3,660295 10,8 1 0 2 and -1 -2 1 17 3,62327 22,99 1 -2 2 18 3,514807 11,02 -1 -2 2 19 3,483591 3,3 0 -2 3 20 3,466081 14,3 0 2 1

[0173] The characteristics of trisodium citrate monoperhydrate dihydrate crystals are listed in the following table 2: Table 2: Crystal structure characteristics of trisodium citrate monoperhydrate dihydrate Chemical formula C6 H11 O11 Na3 Molecular weight 328.12 g / mol Sodium citrate % mass 78,7 molar ratio 1 Hydrogen peroxide % mass 10,4 molar ratio 1 Water % mass 10,9 molar ratio 2 Space group P-1 Crystalline system Triclinic Mesh length (a) 6.2400 (4) Å Mesh length (b) 9,8204(5) Å Mesh length (c) 11.1233(7) Å α 115,846(6) Å β 93,600(5) Å γ 95,350(5) Å Mesh volume 606,69(7) Å ρ calculated 1.796 cm³

[0174] The asymmetric unit contains a fully deprotonated citrate anion, three sodium cations, two water molecules, and two half-molecules of hydrogen peroxide. Thus, the given chemical formula is Nα 3 C 6 H 11 O 11, as presented below and at the figure 3 . HO - OH H 2 O H 2 O Molecular structure of trisodium citrate monoperhydrate dihydrate 2.2 Water solubility

[0175] The solubility of the compounds of the invention is determined by experiments at increasing concentrations of the compound of the invention in deionized water. The results show that trisodium citrate monoperhydrate dihydrate is completely soluble in water (> 900 g / l at 20°C). 2.3. pH of an aqueous solution of the compound

[0176] pH measurements (using a pH meter) show that an aqueous solution of trisodium citrate monoperhydrate dihydrate diluted 20x is 7.6 (± 0.3). Example 3 (invention) : Disodium citrate monoperhydrate anhydrous

[0177] Anhydrous disodium citrate monoperhydrate was prepared as shown in Example 1. 3.1. Crystalline structure

[0178] Powder X-ray diffraction data were collected using a Cu Kα diffractometer as described above and supplemented by synchrotron radiation measurements.

[0179] The resulting diffractogram, presented to the figure 4, and its characteristic lines, recorded in Table 3, shows a crystal structure unknown to the databases, which differs from citric acid, trisodium citrate and all its hydrated forms, disodium citrate and all its hydrated forms, as well as trisodium citrate perhydrate. Table 3: Characteristic lines of anhydrous disodium citrate monoperhydrate Pics 2Θ Relative intensity Index hkl 1 7,10442 2,42 0 1 1 2 6,53808 6,93 1 1 1 3 6,19763 11,5 0 2 0 4 5,03008 18,94 2 2 0 5 4,83206 0,76 1 2 1 6 4,45527 10,07 3 1 1 7 4,34762 32,9 2 2 1 8 4,29193 11,19 4 0 0 9 4,21333 17,21 3 2 0 10 3,97003 19,47 1 1 2 11 3,85293 13,47 401 and 202 12 3,78756 19,04 3 2 1 13 3,67804 12,75 4 1 1 14 3,53769 100 4 2 0 15 3,47303 5,61 1 2 2 16 3,42705 7,44 2 3 1 17 3,32368 6,66 3 1 2 18 3,2801 32,86 2 2 2 19 3,13095 31,11 3 3 1 20 3,09689 19,5 5 1 1

[0180] The characteristics specific to the disodium citrate perhydrate crystal are recorded in Table 4. Table 4: Crystalline structure characteristics of anhydrous disodium citrate monoperhydrate Crystalline system Orthorhombic #61 Pbca Mesh length (a) 8.6396(25) Å Mesh length (b) 12,433(4) Å Mesh length (c) 17,199(5) Å Mesh volume 1847,5(8) Å 3<

[0181] The measurements concerning hydrogen bonds are recorded in Table 5 below: Table 5: Hydrogen bonds in the crystal structure of anhydrous disodium citrate monoperhydrate (*intramolecular) Link H DA, Å H···A, Å D ... A, Å DH ... A, Å Recovery, e E, kcal / m O12-H21···O13 1,041 1,507 2,546 175,0 0,092 16,6 017-H18···O22 0.976 1,852 2,770 155,7 0,041 11,1 017-H18···O13 0.976 2,557* 3,063 112,5 0,009 5,2 O22-H24···O13 1.015 1,585 2,598 174,7 0,080 15,5 O23-H25···O13 0.994 1,605 2,596 174,8 0,064 13,8 C4-H10···O13 1.094 2,340 3,270 141,8 0,015 C2-H7···O13 1.095 2,482* 3,199 121,9 0,012

[0182] The asymmetric unit corresponds to the formula Na₂HC₆H₅O₇(H₂O₂), and thus contains a citrate anion, two sodium cations, and a hydrogen peroxide molecule, as shown below. There are no voids in the structure to accommodate a water molecule. 3.2. Water solubility

[0183] Disodium citrate perhydrate is totally soluble in water (> 800 g / l at 20°C). 3.3. pH of an aqueous solution of the compound

[0184] pH measurements (using a pH meter) show that diluted (20x) in water, the obtained disodium citrate perhydrate crystals have a pH of 5.2 (± 0.3). 3.4. Thermogravimetric Analysis (TGA)

[0185] Thermogravimetric analyses of a crystalline powder of disodium citrate perhydrate according to example 1 were carried out to evaluate its behavior at a temperature of 100 to 220°C.

[0186] Mass loss curves for TGA were obtained using a TA instruments (Waters) under a nitrogen atmosphere and within a temperature range of 30 to 250°C. A temperature ramp of 10°C / min was applied, followed by an isotherm at the final temperature (250°C for this analysis) for a period of 10 minutes. A mass loss of less than 1% occurred below 140°C, likely corresponding to a loss of water of crystallization. The powder then lost between 2 and 3% of its mass between 140 and 220°C.

[0187] These results show excellent stability at high temperatures. Example 4: Co-crystallization of one mole of anhydrous disodium citrate monoperhydrate and three moles of urea perhydrate 4.1. Crystalline Structure

[0188] The resulting diffractogram is presented to the figure 5 .

[0189] The diffraction spectrum obtained shows that the powder produced is a co-crystallization of anhydrous disodium citrate monoperhydrate and urea perhydrate, the most characteristic peaks of which are highlighted. 4.2 pH of an aqueous solution of the compound

[0190] The pH of an aqueous solution of co-crystals of one mole of anhydrous disodium citrate monoperhydrate and 3 moles of urea perhydrate diluted 20x is 5.2 (± 0.3). Example 5: Performance 1. Formulation 1 based on co-crystallized trisodium citrate monoperhydrate dihydrate and urea perhydrate (comparative) 1.1. Formulation Preparation

[0191] 200 g of a co-crystallization containing 1 mole of trisodium citrate monoperhydrate dihydrate and 4 moles of urea perhydrate are mixed with 21 g of urea and 55 g of anhydrous citric acid. The powder mixture is then dissolved in deionized water at various concentrations. 1.2. Biocidal performance on bioassays

[0192] Formulation 1 was tested in a bioassay on various pathogens. The results are presented in Table 6. Table 6: Effective concentration [mg / ml] of formulation 1. Plasmopara viticola 24 Botrytis cinerea <5 Guignardia bidwellii 5 Helminthosporium solani 25 Collelotrichum coccodes 25 Monilia laxa strain 623 18 Monilia laxa strain INRA 50 Serpula lacrimens 18 Staphylococcus aureus 0,064 Pseudomonas aeruginosa 0,256 Erwinia amylovora 1,024 Ralstonia strain 06 0,512 Ralstonia strain R1 0,512 2. Formulation 2 based on anhydrous disodium citrate monoperhydrate 2.1. Formulation Preparation

[0193] The powder in example 3 is dissolved in deionized water at different concentrations. 2.2. Antifungal performance

[0194] Formulation 2 was tested in a bioassay on various pathogens. The results are presented in Table 7. Table 7: Effective concentration [mg / ml] of formulation 2. Erysiphe necator 10 Botrytis cinerea 5-10 Monilia laxa strain 623 10-20 Monilia laxa strain INRA 34-50 Monilia fructigena 34-50 3. Formulation 3 based on anhydrous disodium citrate monoperhydrate and co-crystallized urea perhydrate 3.1. Formulation Preparation

[0195] The powder in example 4 is dissolved in deionized water at different concentrations. 3.2. Antifungal performance

[0196] Formulation 3 is tested in a bioassay on fungi Plasmopara viticola, Erysiphe necator, Guignardia bidwellii and Monilia fructigena. The result is presented in Table 8. Table 8: Effective concentration [mg / ml] of formulation 3. Plasmopara viticola 30 Erysiphe necator 10 Botrytis cinerea 1-5 Guignardia bidwellii 25-50 Monilia laxa strain 623 10-20 Monilia laxa strain INRA 17-25 Monilia fructigena 17-25 4. Formulation 4 based on anhydrous disodium citrate monoperhydrate and co-crystallized urea perhydrate 4.1. Formulation Preparation

[0197] 62 g of the powder described in Example 4 are mixed with 10 g of anhydrous citric acid, 3 g of lactic acid, 2 g of anhydrous calcium lactate, 1.5 g of a surfactant, and 1.5 g of a desiccant. The powder mixture is then dissolved in deionized water at various concentrations. 4.2. Antibacterial performance

[0198] Formulation 4 is tested in a bioassay on six pathogenic strains according to the EN1040 standard. The results are presented at the figure 6 . 5. In vitro tests

[0199] The effectiveness of formulations 2 and 3 as described above was assessed using bioassays on the fungus. Botrytis cinerea on conidia germination (Table 9) and mycelium development (Table 10) compared with the reference chemical fungicide (Teldor, Bayer), as well as bioassays on the fungus Venturia inaequalis on the germination of conidia (Table 11) in comparison with the reference chemical fungicide (Merpan, Adam France). Botrytis cinerea Table 9: Efficacy (%) of formulations 2 and 3 against (conidia germination) formulation / concentration (mg / ml) 2 5 10 Formulation 2 - 100 100 Formulation 3 100 100 100 Teldor (reference) 79 81 81 Botrytis cinerea Table 10: Effectiveness (%) of formulations 2 and 3 with respect to (mycelium development) formulation / concentration (mg / ml) 5 10 15 20 30 Formulation 2 25-49,99 50-74,999 50-74,999 50-74,999 75-100 Formulation 3 75-100 75-100 75-100 75-100 75-100 Teldor (reference) 50-74,999 50-74,999 50-74,999 50-74,999 - Venturia inaequalis Table 11: Efficacy (%) of formulations 2 and 3 against the fungus (conidia germination) Formulation / concentration (mg / ml) 2 5 10 Formulation 2 100 100 100 Formulation 3 100 100 100 Merpan (reference) 100 100 100 6. Antifungal performance: another full-field validation

[0200] The experiment is being conducted in a Swiss vineyard in accordance with Good Agricultural Practices (GAP) standards as defined in Article R 253-1 of the French Rural Code (FR) for data relating to the biological evaluation of plant protection products. The trial aims to assess the development of powdery mildew on both leaves and grape clusters. The vines are treated weekly with a spray solution of 200 L / ha. The trial plots are described as follows: An untreated plot (TNT); A plot treated with formulation 3 at 30g / l, to which 1% of SiO2 and 0.5% of heptamethyltrisiloxanes (wetting agent, De Sangosse - Agridyne) have been added, which corresponds to 6 kg per hectare of vine (Biogel solo); A plot treated with a conventional reference chemical fungicide (conventional program); A plot treated with a reference fungicide authorized in organic farming (organic program).

[0201] The evaluation of the effectiveness of the tested formulation is based on 2 criteria; the percentage of incidence and severity of the disease, whether on the leaves ( figure 8A ) or on the grapes ( figure 8B ). Example 6: Instability of concentrated solutions of citric acid and hydrogen peroxide

[0202] The stability of a concentrated solution of hydrogen peroxide and citric acid is studied.

[0203] To do this, a solution containing 37.5% hydrogen peroxide and 25% citric acid is prepared. The hydrogen peroxide concentration is then measured by permanganometric titration three times over two months. The peracid content is also measured using a colorimetric strip method.

[0204] The results are presented in Table 12: Table 12: Results of the evolution of a solution containing 37.5% hydrogen peroxide and 25% citric acid Date of measurements %w. Hydrogen peroxide %w. Peracids J0 37,5 0 Day 0 + 16 days 32,6 5 Day 0 + 2 months 24,6 5

[0205] These results show that the solution loses 34.4% of its hydrogen peroxide concentration after 2 months. A 5% concentration of peracids is also observed in the solution after 18 days. Furthermore, an increase in pressure followed by gas release is observed over time. Example 7: Comparative performance of the perhydrated citrates of the invention against aqueous solutions of hydrogen peroxide, citrates and citric acid 1. Action on Botrytis cinerea

[0206] Tests were conducted according to a standard protocol on various fungal targets, including Botrytis cinerea, have shown that at equivalent concentrations, neither citrate alone nor hydrogen peroxide alone has a fungicidal or fungistatic effect, unlike the compound of the invention (see table 13 below).

[0207] This is also confirmed by Gil-ad et al. (FEMS Microbiology Letters 1999, 176, 455-461), indicating that Botrytis cinerea can germinate in the presence of hydrogen peroxide at concentrations up to 180 mM (6 mg / mL), and its mycelium can develop at even higher concentrations.

[0208] Disodium citrate perhydrate crystallizes preferentially with hydrogen peroxide, rather than with water, and forms a reactive biocidal barrier. Indeed, when disodium citrate perhydrate is dissolved in an aqueous solution for spraying—that is, when disodium citrate and hydrogen peroxide are sprayed onto a surface—the water evaporates and the disodium citrate perhydrate re-crystallizes to form a reactive biocidal barrier, whereas a hydrogen peroxide solution simply evaporates. This allows for a persistent effect of the product of the invention. 2. Action on Staphylococcus aureus

[0209] Tests were carried out according to a standard protocol on Staphylococcus aureus MRSA, comparing the disodium citrate perhydrate of the invention to sodium citrate, hydrogen peroxide, and a reference antiseptic.

[0210] The results of these tests are recorded in Table 14: Staphylococcus aureus MRSA Table 14: Comparative results of bioassays on MIC value % mM Sodium citrate (pH 5->8) 3.20 mg / ml 0,320 12,40 -> 13,56 Hydrogen peroxide 0.94 mg / ml 0,094 27,58 PVPI (Povidone-iodine) 6.25 mg / ml 0,625 17,13 Ethanol 87.5 mg / ml 8,750 1899,35 disodium citrate perhydrate of the invention 0.03 mg / ml 0,003 0,12

[0211] Given the molecular structure of disodium citrate perhydrate, comparing the effectiveness of the compound of the invention with respect to sodium citrate and hydrogen peroxide is easy (in equimolar).

[0212] It is worth noting that disodium citrate perhydrate has an inhibitory effect on the development (MIC) of Staphylococcus aureus MRSA 230 times greater than that of hydrogen peroxide alone and 103 times greater than sodium citrate.

Claims

1. An alkali metal citrate perhydrate, which is a disodium citrate monoperhydrate, preferably an anhydrous disodium citrate monoperhydrate.

2. The alkali metal citrate perhydrate according to claim 1, in powder form, the powder being physically and chemically stable without significant change in its physical state or chemical composition after one year at a temperature of 20 to 25°C, in particular its active oxygen concentration.

3. The alkali metal citrate perhydrate according to any one of claims 1 to 2, soluble in water, in particular having a solubility greater than or equal to 850 g / l at 25°C in water.

4. The alkali metal citrate perhydrate according to any one of the preceding claims, having a pH between 4 and 8 in aqueous solution.

5. The alkali metal citrate perhydrate according to any one of claims 1 to 3, in the form of a crystal consisting of disodium citrate and hydrogen peroxide.

6. A composition comprising a perhydrate citrate as defined in any one of claims 1 to 2 or 5, and perhydrate urea, in particular in the form of a urea-hydrogen peroxide co-crystal, said composition comprising in particular crystals of disodium citrate perhydrate and crystals of urea perhydrate, in particular in the form of a urea-hydrogen peroxide co-crystal.

7. A pharmaceutical or phytopharmaceutical composition consisting of or comprising disodium citrate perhydrate according to any one of claims 1 to 5.

8. A non-therapeutic use of disodium citrate perhydrate according to any one of claims 1 to 5 as a biocide.

9. The use according to claim 8, wherein said disodium citrate perhydrate is used in the presence of water and / or in the presence of at least one additional compound selected from pH regulators, anti-caking agents, surfactants, wetting agents, anti-foaming agents, anti-drift agents, thickening agents, foaming agents, solidifying agents, fertilizers, phytopharmaceutical products, stabilizers, and mixtures thereof, the additional compound being selected in particular from glycolipids.

10. The use according to claim 8 or 9, to inhibit or prevent the growth of a pathogen on or in a plant, said citrate being in particular applied to the surface of the plant, more particularly at a level of 25 to 1000 ng / dm2, where the pathogen is preferably selected from viruses, bacteria, fungi, and pseudo-fungi, and wherein the plant is preferably selected from fruit-producing plants, vegetable-producing plants, ornamental plants, turf, and cereals.

11. The use according to any one of claims 8 to 12 for disinfecting a fluid or surface, in particular water, air, soils, swimming pools, work surfaces, toilets.

12. A method for preparing an alkali metal citrate perhydrate according to any one of claims 1 to 5, said method comprising: (i) a step of contacting disodium citrate with hydrogen peroxide to obtain said disodium citrate perhydrate, said step (i) optionally being preceded by a step of neutralizing citric acid with a sodium hydroxide, carbonate or citrate to obtain the disodium citrate as mentioned in step (i), or (i') a step of contacting citric acid; a sodium hydroxide, carbonate or citrate; and hydrogen peroxide, to obtain said disodium citrate perhydrate.

13. The method for preparing a composition according to claim 6, said method comprising a step (a) of co-crystallization by contacting disodium citrate; urea; and hydrogen peroxide, said step (a) optionally being preceded by a step of neutralizing citric acid with a sodium hydroxide, carbonate or citrate, to obtain the disodium citrate as mentioned in step (a), or (a') a step of contacting citric acid; a sodium hydroxide, carbonate or citrate; urea; and hydrogen peroxide, to obtain said disodium citrate perhydrate.