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甲马小

铁虫 (小有名气)

[求助] 合成柠檬酸根修饰的磁性纳米粒子时遇到的问题

文献上的制备方法:
Magnetite(Fe3O4) particles were prepared by co-precipitation of FeCl2 and FeCl3 (1:2 molar ratio) by the addition of NH4OH. In a typical reaction, 0.86 g FeCl2 and 2.35 g FeCl3 were mixed in 40 ml water and heated to 80º C under argon in a three-necked flask. While vigorously stirring the reaction mixture, 5 ml of NH4OH was introduced by syringe and the heating continued for thirty minutes. After that, 1g of citric acid (CA) in 2ml water was introduced, the temperature raised to 95º C and the stirring continued for an additional ninety minutes. A small aliquot of the reaction mixture was withdrawn, diluted to twice its volume and placed on a 0.5 Tesla magnet in a vial. At the point when the particles did not settle down under the influence of the magnet, the colloidal solution was stable. The as-formed reaction product contained an excess of citric acid. Therefore, the nanoparticle dispersion was subjected to dialysis against water in a 12-14 kD cut-off cellulose membrane (Spectrum Laboratories, Inc., USA) for 72 hours to remove the excess unbound CA. The citric acid coated magnetic particles are abbreviated as MP-CA.
我的疑问:
反应在较高温度下进行了很长时间(至少2小时),体系一直在通氩气,为了保证内部气压不至于过高,肯定要有出气孔,这这么高温度和这么长时间下,体系的水几乎都挥发没了,请问这个问题如何处理?
谢谢,盼指导!
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hgxy2010

铜虫 (正式写手)

【答案】应助回帖

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感谢参与,应助指数 +1
甲马小: 金币+1 2012-05-10 08:25:15
高温,一直通气肯定会增加溶液的浓度,反应条件就改变了,我觉得你不必要一直通气,可以使氩气充满即可,再或者考虑回流,不过溶液体积还是会变。
7楼2012-05-08 08:44:04
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refnew

专家顾问 (知名作家)


【答案】应助回帖

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感谢参与,应助指数 +1
甲马小: 金币+1 2012-05-10 08:24:48
加个冷凝管

就可以了
2楼2012-05-05 10:13:33
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甲马小

铁虫 (小有名气)

引用回帖:
2楼: Originally posted by refnew at 2012-05-05 10:13:33:
加个冷凝管

就可以了

您好,感谢您的回复!
我加上冷凝管再尝试一下。

另外,想问一下:这个反应进行过程中需要一直通保护气吗?气流大小对反应是否有影响?
3楼2012-05-05 10:22:48
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refnew

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甲马小: 金币+1 2012-05-10 08:24:59
气体是在液面下鼓泡还是在液面上对着液面吹,还是在瓶子里面朝上吹,气流速度;这几个因素对尺寸影响非常大
4楼2012-05-05 10:46:12
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