METHOD OF OBTAINING CARBON NANOTUBES Russian patent published in 2008 - IPC C01B31/00 B82B3/00 

FIELD: chemistry.

SUBSTANCE: mixture of gaseous hydrocarbon and a gas diluent are brought into contact with a catalyst at 800-1000°C, with catalyst heating rate of 100-1000 °C/min. The time for holding the catalyst at the reaction temperature is 1.00-45.00 min with accuracy of controlling the holding time in the pyrolisis zone of 0.10-0.50 min. The catalyst can be in flat substrate form or in powder form or in granular form. The carbon product obtained on the catalyst before extraction from the reactor is cooled in the current of the mixture of the gaseous hydrocarbon and the gas diluent at a rate of 50-200 °C/min. Methane is used as the gaseous hydrocarbon and hydrogen is used as the gas diluent, at a volume ratio of (10-50):(90-50). The catalyst can be: Mo_xFe_yMg_1-x-yO, Mo_xNi_yMg_1-x-yO, where x:y:(1-x-y)=(0.0075-0.1000):(0.0025:0.100):(0.8000-0.9900); Mo_xCo_yMg_1-x-yO, where x:y:(1-x-y)=(0.0025-0.1000):(0.0025:0.100):(0.8000-0.9950); Co_xMg_1-xO, Fe_xMg_1-xO, Ni_xMg_1-xO, where x=(0.0100-0.1000). The catalyst can also be one of Co, Fe or Ni. MgO, SiO₂ or Al₂O₃ can be used as the carrier.

EFFECT: obtaining quality carbon nanotubes with minimum content of nanofibres and other impurities.

1 tbl, 14 ex, 8 dwg