Functionalized ionic liquids and their applications
Inventors
Hariprakasha, Humcha Krishnamurthy • Rangan, Krishnaswamy Kasthuri • Sudarshan, Tirumalai Srinivas
Assignees
Publication Number
US-9871270-B2
Publication Date
2018-01-16
Expiration Date
2034-03-14
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Abstract
Disclosure of functionalized ionic liquids. Use of disclosed ionic liquids as solvent for carbon dioxide. Use of disclosed ionic liquids as flame retardant. Use of disclosed ionic liquids for coating fabric to obtain flame retardant fabric.
Core Innovation
The invention discloses new functionalized ionic liquids characterized by having both amine and alcohol groups within the same molecule, specifically with a hydroxyl group located within 2 or 3 carbons of the amine functionality. These ionic liquids are represented by specific chemical formulas (Formula 1, Formula 2, and Formula 3) which define the possible variations in cationic and anionic structures, accommodating a range of alkyl, aryl, and functional substituents, and various anions.
The core problem addressed is the need for improved solvents for carbon dioxide capture and flame retardants for textile articles. Conventional ionic liquids, while promising, often have high viscosity and limited chemical absorption capacity for CO2, and current flame retardant treatments for fabrics are either non-durable, ineffective, or introduce undesirable properties. Moreover, durable, non-toxic, and multifunctional flame retardant solutions are sought for articles like NYCO fabrics.
The disclosed functionalized ionic liquids demonstrate enhanced properties for carbon dioxide absorption, showing much higher capture capacity than unfunctionalized ionic liquids, and exhibit excellent flame retardant qualities when applied as coatings to various textiles. The invention also describes methods for synthesizing these compounds and their use as electrolytes or additives in batteries and as antistatic coatings, among other potential uses.
Claims Coverage
The patent includes one independent claim covering the central inventive features of the disclosed functionalized ionic liquids and seven additional dependent claims specifying particular applications and compositions.
Functionalized ionic liquid core structure
An ionic liquid represented by the structure of Formula 1, wherein: - R1 and R2 are each independently H, or a C1 to C12 straight-chain alkyl group or branched alkyl group or aryl group; - m is an integer from 1 to 6; - X is —N(R3)—(CH2)q—OH, where R3 is H or C1 to C6 straight-chain or branched alkyl group and q is an integer from 2 to 4; - A− is an anion selected from [BF4]−, [PF6]−, [CH3CO2]−, [HSO4]−, [CF3SO3]−, [(CF3SO2)2N]−, [(CF3SO2)3C]−, [SO4]2−, Cl−, Br−, I−, [N(CN)2]−, [(PO4)(C4H9)2]−, [(PO4)(C2H5)2]−, [(PO4)(C6H5)2]−, [CH3CH2OSO3]−, [CH3OCO2]−, and amino acid.
The main inventive feature is the novel class of ionic liquids with a combined amine and hydroxyl functionality at precise positions, as defined in Formula 1, with specific allowable cation and anion structures. All claimed applications and compositions in dependent claims are based on this core structure and its properties.
Stated Advantages
Amino-alcohol functionalized ionic liquids show much higher carbon dioxide absorption capacity (up to 20×) than unfunctionalized ionic liquids at low CO2 pressures.
The ionic liquids exhibit high thermal stability, being stable up to approximately 280°C in both nitrogen and air.
Flame retardant coatings using these ionic liquids provide durable fire resistance to fabrics and are not removed after repeated washing.
The ionic liquids are colorless and do not interfere with other properties of treated fabrics, such as camouflage.
The ionic liquids can impart multiple functionalities to textiles, including antistatic, conductive, and antimicrobial properties.
The flame retardant property is effective for both cotton and nylon-based fabrics.
The CO2 absorption by the functionalized ionic liquids is reversible and stable over multiple absorption/desorption cycles.
The viscosity increase of these ionic liquids after CO2 absorption is significantly less than that observed for anion-functionalized ionic liquids.
Documented Applications
Use of the ionic liquids as solvents for carbon dioxide capture.
Use of the ionic liquids as flame retardant coatings for textile fabrics, including cotton, cellulose, rayon, nylon, polyester, polyurethane, polyamide, and aramid.
Use of the ionic liquids as electrolytes in lithium ion batteries.
Use of the ionic liquids as flame retardant additives to electrolytes in lithium ion batteries.
Use of the ionic liquids as electrolytes in metal air batteries.
Use of the ionic liquids as flame retardant additives to electrolytes in metal air batteries.
Use of the ionic liquids as antistatic coatings.
Use of ionic liquids as desiccants to remove moisture and chloride and other corrosive chemicals.
Use as solvents in organic reactions.
Use as a medium for electrodeposition of metal coatings including nickel and cobalt coatings.
Use as a solvent or medium for coating powders and preparing nano metal and nanometal oxide powders.
Use as a scrubbing material for desulfurization.
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