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djl2006

至尊木虫 (正式写手)

[求助] 制备出的铬配合物,为什么要进行零下80度冷冻呢?这一步的作用是什么?

A suspension of nicotinic acid (3.60 g, 29.24 mmol)
in DI water (120 mL) was heated to 70-80' C. Glutamic acid
(2.22 g, 15.1 mmol) was added to it and continued heating.
Once the whole material was dissolved a solution of Chromium
chloride (CrC1,.6H20, 4.05 g, 15.2 mmol) in DI water
(20 mL) was added to it. The mixture was stirred at 70-80' C.
for 9h and cooled to room temperature, frozen at -80' C. and
lyophilized.
上述过程中,制备出的铬配合物,为什么要进行零下80度冷冻呢?这一步的作用是什么?
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xiaoshuchong

金虫 (正式写手)

那不是写着了吗,冷冻干燥。
2楼2012-10-14 21:43:43
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djl2006

至尊木虫 (正式写手)

引用回帖:
2楼: Originally posted by xiaoshuchong at 2012-10-14 21:43:43
那不是写着了吗,冷冻干燥。

为什么在那么低的温度下,冷冻干燥呢?而且此配合反应应该调pH值才能进行,步骤中也没有提。
3楼2012-10-15 09:39:13
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