Octanohydroxamic Acid (Caprylhydroxamic Acid) is an important multifunctional compound with a hydroxamic acid functional group. It can be used as a preservative, chelating agent and extractant in a wide range of biological, pharmaceutical, chemical and cosmetic applications. It is reported to be used as a growth-promoting feed additive; a biomedical therapeutic agent; in agriculture as an insecticide, antibacterial agent and plant growth regulator; in industry, it can be used as an antioxidant, corrosion inhibitor, extractant of toxic elements, mineral flotation agent, and redox switch for electronic devices.

Chemical Properties

Octanohydroxamic Acid is a white to brown crystalline solid that is stable under normal environmental and use conditions. Its dissociation constant (pKa) is estimated to be 9.56, however, it may hydrolyze to octanoic acid and hydroxylamine at very high or low pH values. The decomposition products at high temperatures are ammonia and

carbon and nitrogen oxides. In addition, it forms strong complexes with oxidized transition metals almost instantly and may react with oxidants and acids.

Synthesis

Octanohydroxamic Acid is synthesized by transamidation of methyl or ethyl octanoate with hydroxylamine. Methanol or ethanol is a byproduct of the process. Depending on the octanoate used, the reaction is carried out in methanol or ethanol under reflux conditions. Octanohydroxamic Acid is then isolated and purified by recrystallization from ethyl acetate, followed by washing and drying of the crystalline Octanohydroxamic Acid to obtain a component with a purity of more than 99%. Its synthesis route is shown in the figure below:

Application in Skin Care

Octanohydroxamic Acid is a commonly used preservative in skin care products, especially those for sensitive skin, with multiple functions such as antibacterial, antibacterial, moisturizing and softening skin. In addition, it is also used in a variety of cosmetic formulations. Octanohydroxamic Acid is permitted in body and hand products at a maximum leave-on concentration of 0.25% and 0.3% for rinse-off, and in bath soaps and detergents at a maximum leave-on concentration of 0.9%. It can be used in products around the eyes (eyebrow pencils and "other" eye makeup) at a maximum of 0.2%, in formulations in contact with mucous membranes (bath soaps and detergents) at a maximum of 0.3%, and in baby lotions, oils and creams at a maximum of 0.15%. The use of octanohydroxamic acid is not subject to any restrictions under EU cosmetic regulations.