Electrochemical reduction of titanium tetrabromide in a hydrophobic room-temperature molten salt

The electrochemical reduction of tetravalent titanium species was investigated in hydrophobic l-n-butyl-l-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (BMPTFSI) room-temperature molten salt (ionic liquid). Titanium tetrabromide was soluble in BMPTFSI regardless of the presence of BMPBr as a Lewis base. The stepwise reduction from Ti(IV) to Ti(III) and probably Ti(II) was observed in BMPTFSI containing TiBr₄ without BMPBr. The potentiostatic cathodic reduction gave some deposits at 180°C. The reduction of Ti(IV) species at -2.3 V led to the deposition of some Ti compounds containing TFSI^- anions. The electrodeposit containing Ti without TFSI^- anions was obtained by the potentiostatic cathodic reduction below - 3.0 V.