直鎖アルキルアミン-AlCl_3系を用いる多孔質アルミナ前駆体の合成と構造

概要

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Porous alumina precursors have been prepared from an aqueous solution of AlCl_3 by an addition of various n-alkylamines (C_nH_<2n+1>NH_2) at pH 6.2 and pH 9.6. Alkylamines with n≧6 produced the unknown phase, which showed a single X-ray reflection at 2 θ=4-5゜. The corresponding d values (1.99-2.42 nm) depended on the carbon number of alkylamines. The XRD, FT-IR and TG measurements suggested that the precipitate with the long periodicity is an intercalation composite between Al hydroxide, alkylamine, and water. The thermal decomposition of the precipitate obtained at pH 6.2 gave rise to the maximum BET surface area (374 m^2/g) at 500℃. The dependence of the surface area on the carbon number showed that the precipitate containing alkylarnines of n≧6 is quite effective in producing porous alumina structure after calcination at 350-600℃. Gas evolution by the thermal decourposition of alkylamines incorporated into the structure of the precipitate appears to play a key role in the formation of the micropores.
社団法人日本セラミックス協会の論文
1998-06-01