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本文研究了在活性 MgO 上进行的异丙醇的催化氧化反应和其晶粒长大及烧结的关系。把异丙醇加到由 Mg(OH)_2经500℃煅烧90min 得到的活性 MgO 中,并和未加异丙醇的试样同时在130℃、230℃、350℃和700℃等温度下再热处理70min。用 X 射线宽化法测定晶粒尺寸,发现在350℃热处理以后,加异丙醇的试样的晶粒尺寸比未加异丙醇的大。透射电镜观察亦得相同的结果。在加异丙醇的试样的非等温粒长大过程中,发现在300～400℃的温度范围内晶粒长大速度特别快。同时此温度范围内有一明显的吸热谷出现在差热曲线上。显微镜测得加异丙醇的烧结块的晶粒尺寸比未加的大。根据催化理论提出了一个可能的机理,即在 MgO 表面上进行的异丙醇的氧化反应产生-OH 根。当这些-OH 从 MgO 表面上脱附时产生氧空位或者形成“氧桥”。
In this paper, we studied the catalytic oxidation of isopropanol over activated MgO with its grain growth and sintering. Isopropyl alcohol was added to the active MgO obtained by calcining Mg (OH) _2 at 500 ° C for 90 min and added to the sample without isopropyl alcohol at 130 ° C, 230 ° C, 350 ° C and 700 ° C Heat treatment 70min. The grain size was measured by X-ray broadening. It was found that the grain size of the sample with isopropanol was larger than that without isopropanol after the heat treatment at 350 ℃. Transmission electron microscopy also had the same result. During the growth of non-isothermal grains of isopropanol samples, it was found that the grain growth rate was very fast in the temperature range of 300-400 ℃. At the same time there is a significant endothermic valley in this temperature range in the differential thermal curve. The crystallite size of the agglomerate plus isopropanol measured by the microscope was larger than that without addition. A possible mechanism is proposed according to the catalytic theory that the oxidation reaction of isopropanol on the surface of MgO produces -OH radicals. Oxygen vacancies or “oxygen bridges” are created when these -OHs are desorbed from the MgO surface.