Standardization of Solid Superacid of Sulfated Zirconia Prepared Using Zirconia Supplied by Catalysis Society of Japan

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A recommended preparation procedure and applying method for some catalytic reactions were proposed based on the results of this investigation.As the starting material for catalyst preparation, JRC-ZRO-2 and-5 supplied by Catalysis Society of Japan are recommended. Zirconia gel should be well dried before sulfation at 300 ℃ or below.Two preparation methods of equilibrium adsorption method and ammonium sulfate kneading method had been investigated. The zirconia gel was sulfated with high reproducibility in both procedure. The sulfated zirconia with high surface area and high sulfate content was obtained when the non crystallized gel was used. The reproducibility of sulfate content on the surface was high in the ammonium sulfate kneading method. However, there was a tendency that unnecessary sulfate ions, which did not relate to the formation of active sites, remained on the surface. The recommended calcinations temperature is 650 ℃. From the reason of temperature distribution in a furnace, the calcinations at 600 ℃ is strongly recommended.The sulfated zirconia can be kept without care because this was calcined at high temperature. This can be applied for several reactions without pretreatment. It is desirable to remove adsorbed water by heating before use. The pretreatment at 500 ℃ is avoided because the decrease of acid amount was observed in some cases.Thermogravimetry is recommended as the method to confirm the sulfated zirconia production. The temperature of weight decrease accompanying the decomposition of sulfated ions should be checked.