A process for producing a high-purity hafnium amide includes the steps of (a) adding a compound which contains a carbonyl group or sulfonyl group and is represented by the formula of A(O.sub.yXO.sub.nR.sub.f).sub.m (e.g., CF.sub.3SO.sub.3H, Hf(CF.sub.3SO.sub.3).sub.4, (CF.sub.3SO.sub.2).sub.2O, CF.sub.3CO.sub.2H, CH.sub.3SO.sub.3H, C.sub.6H.sub.5SO.sub.3H, and (CH.sub.3SO.sub.2).sub.2O), to a crude hafnium amide which is represented by the formula of Hf[N(R.sub.1)(R.sub.2)].sub.4, where each of R.sub.1 and R.sub.2 independently represents a methyl group or ethyl group, and which contains a zirconium component as an impurity; and (b) subjecting a product of the step (a) to a distillation under reduced pressure, thereby removing the zirconium component from the crude hafnium amide.
Disclosed are first to sixth processes for respectively producing hafnium tetra-tertiary-butoxide, tetrakis(acetylacetonato)hafnium, tetrakis(1-methoxy-2-methyl-2-propanolato)hafnium, hafnium tetra-tertiary-amyloxide, tetrakis(3-methyl-3-pentoxy)hafnium, and tetrakis(hexafluoroacetylacetonato)hafnium. The first process includes the steps of (a) adding a compound A(O.sub.yXO.sub.nRf).sub.m (e.g., CF.sub.3SO.sub.3H) to a crude hafnium amide Hf[N(R.sub.1)(R.sub.2)].sub.4; (b) subjecting a product of the step (a) to a distillation under reduced pressure; (c) adding a lithium alkylamide Li(NR.sub.3R.sub.4) to a fraction obtained by the step (b); (d) subjecting a product of the step (c) to a distillation under reduced pressure; (e) adding tertiary butanol to a fraction obtained by the step (d); and (f) subjecting a product of the step (e) to a distillation under reduced pressure. The tertiary butanol of the step (e) is replaced with acetylacetone, 1-methoxy-2-methyl-2-propanol, tertiary amyl alcohol, 3-methyl-3-pentanol, and hexafluoroacetylacetone in the second to six processes, respectively.
