Abstract: Rare earth thiolates, lanthanum tri(isooctyl thioglycolate) and lanthanum tri(dodecyl thiolate), were prepared from lanthanum oxide by utilizing exchange reaction of rare earth alkoxide. The products were characterized via TGA, FTIR, ¹H NMR, ICP and element analysis. The optimization of synthesis condition was made. The optimal synthesis condition of lanthanum isopropoxide is at the temperature of 80 ℃ for 2 h; the optimal synthesis condition of lanthanum tri(dodecyl thiolate) is at the temperature of 110 ℃ for 2 h and the dodecyl thiol overdoses by 24％; and The optimal synthesis condition of lanthanum tri(isooctyl thioglycolate) is at the temperature of 60 ℃ for 2 h and the isooctyl thioglycolate overdoses by 32％.

Key words: Thiolate, Lanthanum, Isooctyl thioglycolate, Dodecyl thiol