Mechanical activation of fullerene containing soot during extraction of higher and endohedral metallofullerenes

Abstract

For extraction of higher fullerenes and endohedral metallofullerenes (EMF) with yttrium from fullerene-containing carbon soot (soot) obtained by combined spraying of graphite and yttrium oxide powders in an arc plasma, we developed a device (Extractor*) that provides mechanical activation effects on agents combined with filtration. It has been shown that the soot recovery percentage of a mixture of higher fullerenes and EMF with different solvents (carbon disulfide, o-xylene, pyridine) and the EMF mass fraction in the mixture is significantly higher than in the extraction with a Soxhlet apparatus traditionally used for these purposes. The time spent on the extraction process is reduced significantly. Due to a known reaction with titanium chloride (TiCl4) and removal of a solution of empty fullerenes, subsequent bonding of EMF with yttrium into an insoluble complex directly in the extractor allows the product to be significantly enriched with EMF. In general, we were able to significantly reduce both the duration of extraction of the fullerenes mixture and EMF and the production of EMF separately.

Highlights

1. A mechanical extractor (Extractor*) developed by us, which allows processing a larger amount of carbon black and, accordingly, extracting more fullerenes per unit of time, has been applied.

2. The percentage of extraction from the soot of a mixture of higher fullerenes and EMF with various solvents was significantly higher than with extraction using the Soxhlet apparatus.

3. It has been shown that mechanical extractor using makes it possible to increase the coefficient of mass transfer from the surface of the particles to the extracting agents.

4. The Extractor* was first used for the non-HPLC separation of endohedral metallofullerenes with TiCl4. The use of the new device made it possible to isolate a product significantly enriched in endohedral metallofullerenes.

Keywords:

• Fullerenes
• endohedral metallofullerenes
• extraction
• enrichment
• titanium chloride

Availability of data and material (data transparency)

Not applicable. The authors confirm that the data supporting the findings of this study are available within the article.

Acknowledgements

The authors thank Dudnik A.I., Osipova I.V. for conducting the synthesis of carbon soot and atomic emission spectroscopy using the equipment of the Kirensky Institute of Physics FRC KSC SB RAS.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The reported study was funded by RFBR according to the research project № 18-29-19003.