Metal complexes of b-diketones and/or polyphenols by green chemistry, preparation method thereof, sunscreen thereof, skin or hair tone concealer thereof, hair dyeing thereof and other uses thereof

Abstract

The present invention relates to a method to synthesize with high yield a colored metal complex of β-diketones and/or polyphenols by mechanochemistry without using aqueous or organic solvents and covers new complexes obtained therefrom. In an embodiment, only the reactants, a metal alkoxide and a β-diketone and/or a polyphenol, are present and react at different molar ratios to form a metal complex in the form of a homogeneous colored material (i.e. powder) with high yield. If curcumin is used, the color of the final metal complex dye depends on several factors such as the curcuminoids, the metal, the type of alkoxide used, the stoichiometric molar ratio of both reactants and the additives used. If titanium alkoxide and any additive is used, a red or violet colored titanium curcumin complex in powder form is produced. The production process of the metal complex in powder form is characterized by facility of scale up. The entire product is ready to be used in several applications. If polyphenols such as ferulic acid, quercetin, ellagic acid or lignin are used instead of curcumin, other colored complexes are obtained using mechanochemistry. In addition, the product comprising metal complexes of β-diketones and/or polyphenols is characterized by green chemistry manufacture. Besides, these metal complexes of β-diketones and/or polyphenols in several formulations are characterized by improved stability under storage conditions and improved sun protection against UV rays for human skin and human hair. The product is ready to be used alone or in combination with other additives or active ingredients in different formulations. The invention also covers the use of these metal β-diketones/polyphenol complexes in food, cosmetics, the pharmaceutical field and in the creativity field, as sunscreen, skin and hair concealer or foundation in powder form or cream, keratinous dye, textile dye, food dye, dye emulsions, miniemulsions, polymer colloids and catalysts. The production process of these novel metal-complex dyes is also characterized by rapid production of colored compounds without using solvents and, thus, ecofriendliness. The process of the production of metal β-diketone and/or polyphenol complexes is characterized by the non-formation of toxic by-products and high yield. In addition, the present invention comprises a hair dyeing molecule or formulation and procedure combining excellent dyeing properties with reduced risk of development cancer or allergies, while being ecological and of the natural origin.

Dependencies are inferred from the claim text.