Al-isopropoxide dispersed into isopropanol was heated in an autoclave above the critical point of propanol(23$5^{circ}C$, 4.7MPa). Propanol coexisting Al-isopropoxide produced some water during the condensation reaction to isopropul ether, while only propanol did not change under that conditions. This water hydrolyzed Al-isopropoxide to form an alumina at 30$5^{circ}C$ and 11.0MPa. This alumina had a similar X-ray diffraction pattern of $chi$-alumina. The heating treatment showed the aluminal transformed directly to ${alpha}$-alumina around 110$0^{circ}C$, not to pass via any other intermediate aluminas. The aluminal was named pseudo $chi$-alumina as a new phase. As-prepared alumina was fine powder of about 20nm, and had about 5% weight loss in the temperature range from 30$0^{circ}C$ to 65$0^{circ}C$, and the IR spectral showed no constitutional water.