Patent ID: 7518008

Claim:
A process for producing hafnium tetra-tertiary-butoxide Hf(OC 4 H 9 ) 4 , comprising the steps of: (a) adding a compound containing a carbonyl or sulfonyl group, the compound being represented by the formula of A(O y XO n Rf) m , wherein A is a hydrogen, oxygen, or hafnium atom, X is a carbon or sulfur atom when A is a hydrogen atom or oxygen atom, X is a sulfur atom when A is a hafnium atom, each of m, n and y is 1, when A is a hydrogen atom and X is a carbon atom, m, n and y are respectively 1, 2 and 1, when A is a hydrogen atom and X is a sulfur atom, m, n and y are respectively 2, 1 and 0, when A is an oxygen atom and X is a carbon atom, m, n and y are respectively 2, 2 and 0, when A is an oxygen atom and X is a sulfur atom, m, n and y are respectively 4, 2 and 1, when A is a hafnium atom, Rf is a C 1 -C 12 alkyl group, C 1 -C 12 perfluoroalkyl group, C 6 -C 12 aryl group, or C 4 -C 12 heteroaryl group, when A is a hydrogen atom or oxygen atom, Rf is a C 1 -C 12 perfluoroalkyl group when A is a hafnium atom, to a crude hafnium amide which is represented by the formula of Hf[N(R 1 )(R 2 )] 4 , where each of R 1 and R 2 independently represents a methyl or ethyl group, and which contains a zirconium component as an impurity; (b) subjecting a product of the step (a) to a distillation under reduced pressure, thereby removing the zirconium component from the crude hafnium amide; (c) adding a lithium alkylamide represented by the formula of Li(NR 3 R 4 ), where each of R 3 and R 4 independently represents a methyl or ethyl group, 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 C 4 H 10 O to a fraction obtained by the step (d); and (f) subjecting a product of the step (e) to a distillation under reduced pressure.