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huijieyu

新虫 (初入文坛)

[求助] 求助最基本的sol gel制备gamma alumina.

happy new year.
COuld I ask for some advice on sol gel preparationi of Al2O3?
According to one paper: mesoporous gamma-Al2O3:
The mesoporous Al2O3 materials have been prepared using the following procedure: 4.2 g of aluminium i-propoxide and 3.6 g of glucose were dissolved in 54 ml of distilled water, the resultant solution was stirred at room temperature for 30 min. The molar ratio of Al3+:glucose:H2O in the solution was 1:1:75. Then a diluted aqueous nitric acid (10 wt.%) solution was added dropwise to adjust the pH value. After standing for 5 h, the mixture was heated at 100 °C in open air to remove water and all other volatiles. The resulted solid was then calcined at 600 °C for 6 h to remove the template.
My questions:
1. 这个制备是要用什么反应器? 80度水解和缩聚时, 很多水会从烧杯中流失. 我用三颈瓶加回流冷凝管, 也发现很多水在瓶壁和管口. 所以没法控制水的molar ratio啊?
2. 水解的pH5.5, 如何控制啊? 80度时, 用pH meter插到反应液中连续检测吗?
我从没看到过无机材料制备, 请指教.
THANKS
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banditi

木虫 (职业作家)

【答案】应助回帖

感谢参与,应助指数 +1
1. 一般用三口烧瓶即可;如果想回流水,冷凝管加冷水肯定是差事。若想尽量地冷凝,还是用低温恒温槽,用乙二醇冷凝水蒸气吧;
2. 水解的pH值可用精密试纸来测定,没用过PH计。看看说明书吧,能不能在高温下测。但是我认为不需要连续测;
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2楼2012-01-25 21:49:57
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huijieyu

新虫 (初入文坛)

引用回帖:
2楼: Originally posted by banditi at 2012-01-25 21:49:57:
1. 一般用三口烧瓶即可;如果想回流水,冷凝管加冷水肯定是差事。若想尽量地冷凝,还是用低温恒温槽,用乙二醇冷凝水蒸气吧;
2. 水解的pH值可用精密试纸来测定,没用过PH计。看看说明书吧,能不能在高温下测。但 ...

thanks
3楼2012-01-26 19:24:57
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