Fullerene purification is the art of obtaining a fullerene compound free of contamination. In fullerene production mixtures of C₆₀, C₇₀ and higher homologues are always formed. Fullerene purification is key to fullerene science and determines fullerene prices and the success of practical applications of fullerenes. The first available purification method for C₆₀ fullerene was by HPLC from which small amounts could be generated at large expense. Fullerene C540 Fullerenes are one of only four types of naturally occurring forms of carbon (the other three being diamond, graphite and ceraphite). ... Fullerene C540 Fullerenes are one of only four types of naturally occurring forms of carbon (the other three being diamond, graphite and ceraphite). ... Chromatography is a family of analytical chemistry techniques for the separation of mixtures. ...

Experimental purification strategies

• A recent kilogram scale fullerene purification strategy was demonstrated by Nagata et al ^[1]. In this method C₆₀ was separated from a mixture of C₆₀, C₇₀ and higher fullerene compounds by first adding the amidine compound DBU to a solution of the mixture in 1,2,3-trimethylbenzene. DBU as it turns out only reacts to C₇₀ fullerenes and higher which reaction products separate out and can be removed by filtration. C₆₀ fullerenes do not have any affinity for DBU and are subsequently isolated. Other diamine compounds like DABCO do not share this selectivity.
• C₆₀ but not C₇₀ forms a 1:2 inclusion compound with cyclodextrin (CD). A separation method for both fullerenes based on this principle is made possible by anchoring cyclodextrin to colloidal gold particles through a sulfur - sulfur bridge ^[2]. The Au/CD compound is very stable and soluble in water and selectively extracts C₆₀ from the insoluble mixture after refluxing for several days. The C₇₀ fullerene component is then removed by simple filtration. C₆₀ is driven out from the Au/CD compound by adding adamantol which has a higher affinity for the cyclodextrin cavity. Au/CD is completely recycled when adamantol in turn is driven out by adding ethanol and ethanol removed by evaporation. 50 mg of Au/CD captures 5 mg of C₆₀ fullerene.

An amidine is a functional group or type of chemical compound that has two amine groups attached to the same carbon atom with one carbon-nitrogen double bond,exactly its derivate of acid,when suspended the double bond is protonized: HN=CR-NH2. ... DBU or 1,8-diazabicyclo(5. ... DABCO or 1,4-diazabicyclo[2. ... In host-guest chemistry an inclusion compound is a complex in which one chemical compound the host forms a cavity which molecules of a second compound the guest are located. ... Cyclodextrins are cyclic oligomers of glucose which typically contain 6-8 monomers in a ring. ... Colloidal gold, or more precisely gold nanoparticles are sub-micrometre sized particles of gold, usually found in the form of a suspension in water (hence colloid), in which case the liquid usually appears to be either an intense red colour (for particles less than 100 nm), or a dirty yellowish... General Name, Symbol, Number sulfur, S, 16 Chemical series nonmetals Group, Period, Block 16, 3, p Appearance lemon yellow Atomic mass 32. ... Diagram of typical reflux apparatus. ... The article is about the separation process. ... Adamantane (Tricyclo[3. ... The international symbol for recycling. ... Ethanol, also known as ethyl alcohol or grain alcohol, is a flammable, colorless chemical compound, one of the alcohols that is most often found in alcoholic beverages. ... The milligram (symbol mg) is an SI unit of mass. ...

References

1. ^  Kilogram-scale [60]Fullerene Separation from a Fullerene Mixture: Selective Complexation of Fullerenes with 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) Koichi Nagata, Eiji Dejima, Yasuharu Kikuchi, Masahiko Hashiguchi Chemistry Letters Vol. 34 2005, No. 2 p.178. Abstract
2. ^  Thio[2-(benzoylamino)ethylamino]--CD fragment modified gold nanoparticles as recycling extractors for [60]fullerene Yu Liu, Ying-Wei Yang and Yong Chen Chemical Communications, 2005, (33), 4208 - 4210 Graphical abstract Suppl. data Full text