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Topic: How to dry K3PO4?  (Read 7088 times)

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Offline Telamond

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How to dry K3PO4?
« on: August 01, 2011, 10:37:31 AM »
Wasn't sure where to put this (inorganic or organic). But the question is in the subject line "How do I dry K3PO4?". I think the one that I use absorbed some water.


Offline enahs

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Re: How to dry K3PO4?
« Reply #1 on: August 01, 2011, 10:55:50 AM »
Heat it in a crucible to drive water off.


Offline Telamond

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Re: How to dry K3PO4?
« Reply #2 on: August 02, 2011, 01:28:15 AM »
How high temperature would I usually need?

Offline enahs

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Re: How to dry K3PO4?
« Reply #3 on: August 02, 2011, 09:40:38 AM »
Hot fast. Make the bottom of the crucible red hot. Not super bright red all over, but have it glowing red a little.

Offline cheese (MSW)

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Re: How to dry K3PO4?
« Reply #4 on: August 18, 2011, 08:22:55 PM »
The CRC lists the mp of K3PO4 as 1340 °C without dec.  But it is hygroscopic!  Cooling after heating in an open crucible will cause it to reabsorb moisture.
You need to put it into a Schlenk tube and heat it on on a high vac line at say 150 °C (silicone oil bath) overnight and dry to const weight (check IR for O-H).
And keep your dried product under N2. You might even get away with putting the sample under high vac at RT in a desiccator over P2O5.  Good luck!   

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