Direct reduction with carbon is thermodynamically impossible at all temperatures; instead, titanium(IV) oxide is reduced directly using hydrogen gas ($H_2$) at high temperatures.

Direct reduction with carbon produces titanium carbide ($TiC$), which makes the metal extremely brittle; instead, titanium(IV) oxide is converted to titanium(IV) chloride ($TiC{l}_4$) and reduced with magnesium or sodium.

Direct reduction with carbon is highly exothermic and leads to uncontrollable thermal runaway; instead, titanium(IV) oxide is dissolved in molten cryolite ($N{a}_{3}Al{F}_6$) and extracted via electrolysis.

Direct reduction with carbon is too slow to be industrially viable; instead, titanium(IV) oxide is reacted with scrap iron ($Fe$) in a displacement reaction to yield pure titanium.