Ionic Liquids Derived from Vitamin C as Multifunctional Active Ingredients for Sustainable Stored-Product Management

Abstract

This study is focused on the utilization of naturally occurring ascorbic acid (vitamin C) in the synthesis of biologically inspired ionic liquids with attractive application potential. The ionic liquids with the ascorbate anion were obtained in high yield (>90%) via a simple, "green" two-step procedure using well-known, cost-effective, and commercially available alkyltrimethylammonium, dialkyldimethylammonium, and alkylmethylbis(2hydroxyethyl)ammonium cations. Three positive ions in this group used for syntheses are derived from renewable resources, such as vegetable oil or animal fat. The study confirmed the strong influence of the chemical structure of the cation on the stability of the compounds obtained in the air, as well as in aqueous solutions. In addition, the synthesized ionic forms of vitamin C exhibited very good antibacterial and antifungal properties against different microorganisms, including pathogens. The tests also revealed the excellent or good deterrent activity toward common stored-grain insects (granary weevil, confused flour beetle, and khapra beetle), reaching the values determined for azadirachtin, known as the reference antifeedant. The best results were achieved with products containing two long alkyl substituents in the cation (dimethyldioctylammonium and didecyldimethylammonium) that proved to be extremely effective against all the organisms tested. The results of the biological activity indicate that the products synthesized belong to the third generation of ionic liquids. In conclusion, ascorbate-based ionic liquids with multifunctional (antibacterial, antifungal, antifeedant, and antioxidant) properties have substantial potential to be used in the storage of crop protection products.

Physical Properties of an Ionic Liquid Composed of Two Water-Soluble Vitamins and Enhanced Skin Permeation of Both Vitamins

“…It was surprising that the combined solubility of VC and VB 6 in 1,3-butanediol was about 87% (weight ratio). The solubility of VC in 1,3-butanediol was 41.9%, which was much higher than the advertised value (ca 25%) for the highest concentration of VC using polyethylene glycol from the patent information [26]. On the other hand, the IL prepared in this study was not freely soluble in diethyl sebacate.…”

Use of ammonium salts or binary mixtures derived from amino acids, glycine betaine, choline and indole-3-butyric acid as plant regulators

“…These results are in agreement with previous reports of no change in l max for either ascorbic acid or its anion. 30 The 1 H and 13 C NMR spectra were analysed to identify changes in the chemical shis of the products relative to the initial substrates. Chemical shis in the 1 H NMR spectrum can be used to identify ionic or acidic forms of IBA.…”

Third-generation ionic liquids with N-alkylated 1,4-diazabicyclo[2.2.2]octane cations and pelargonate anions

“…24 The methodology used and described above has been successfully used in previous studies regarding ionic liquids. [39][40][41] 33 Potassium hydroxide (0.05 mol) was then added to the precursor solution, which was previously dissolved in 50 mL of anhydrous methanol. The reaction proceeded at ambient temperature with continuous stirring for 1 h. The by-product (potassium bromide) was separated from the solution by ltration on a funnel equipped with a uted lter.…”