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Vosoryx
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Registered: 18-6-2017
Location: British Columbia, Canada
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A few years ago I synthesized a small amount of POCl3, IIRC I planned on using it as a catalyst for something, clearly never got around to it and that
experiment got lost.
I can't recall the exact procedure, but it involved passing chlorine gas over a mixture of Trisodium Phosphate and (I think?) activated carbon in a
quartz tube heated to a few hundred degrees. The resulting mess of chemicals were condensed and then distilled, I had to do the reaction a few times
to generate enough to distill as my quartz tubes are very small in diameter.
The exact procedure I got from here but all my chemistry books are on my old hard drive at home...
That reaction would only really work for small scale amounts, and I hate doing anything with chlorine gas.
"Open your mind son, before someone opens it for you." - Dr. Walter Bishop
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draculic acid69
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A pound for $21, problem solved. U can make all the pocl3 or poly phosphoric acid you'd ever need.
This deal sounds like a logical choice.
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draculic acid69
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Quote: Originally posted by Vosoryx  | A few years ago I synthesized a small amount of POCl3, IIRC I planned on using it as a catalyst for something, clearly never got around to it and that
experiment got lost.
I can't recall the exact procedure, but it involved passing chlorine gas over a mixture of Trisodium Phosphate and (I think?) activated carbon in a
quartz tube heated to a few hundred degrees. The resulting mess of chemicals were condensed and then distilled, I had to do the reaction a few times
to generate enough to distill as my quartz tubes are very small in diameter.
The exact procedure I got from here but all my chemistry books are on my old hard drive at home...
That reaction would only really work for small scale amounts, and I hate doing anything with chlorine gas. |
This also sounds doable for the more adventurous members
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zed
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Location: Great State of Jefferson, City of Portland
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Ummm. Things get lost. This has been on the site for years. Once upon a time, a poster here wrote a book.
It's a good book. Not cheap... About 70-80 Bucks in Paperback. Gotta search for it too! POCl3 prep is included. Though Chemplayer's/Querty
Querty's Acetyl Chloride prep, and The Benzoyl Chloride Chlorination are very useful, sometimes you gotta have the fancy stuff... PCl3, PCl5, POCl3,
Oxalyl Chloride.
........................................................................................
See Lerner, Leonid (2011). Small-Scale Synthesis of Laboratory Reagents with Reaction Modeling. Boca Raton, Florida: CRC Press. pp. 169–177. ISBN
9781439813126. PDF available from libgen.
Quote:
19.3.1 Preparation from P2O5
The best reaction vessel for this preparation is a test tube with a quickfit joint, a capacity of at least 100 mL, and at least 22 mm in diameter. If
this is not available, a 100-mL, single-neck flask can be used instead with a slight loss of yield. Scaling the reaction requires proportionally
larger vessels.
First, 35.1 g (0.25 mol) of phosphorus pentoxide is rapidly introduced into the reaction vessel, ensuring that as little atmospheric moisture as
possible reacts with the P2O5, as it subsequently generates HCl and HPO3, which attacks the glass. The transfer is best done by inverting a powder
funnel inserted into the reaction vessel, over the mouth of the reagent bottle, and tilting until approximately the right amount of reagent is
transferred into the flask. Next, 34 g (0.58 mol) of finely ground and thoroughly desiccated (1 h at 250°C) NaCl is added, and the reagents
thoroughly mixed. The approximately twofold excess of NaCl improves the yield by about 10%. Finally, about 10 g NaCl is poured in a layer on top of
the mixture, which serves to convert unreacted P2O5 subliming from the reaction zone (bp 360°C). The reaction vessel is placed in an air oven and
connected to a bend leading through a Liebig condenser to a receiver flask immersed in cold water. The outlet from the flask is vented through a CaCl2
protection tube with a bubbler optionally attached for observation of reaction progress.
The oven is rapidly heated to 270°C, from where the temperature is raised more slowly to 450°C at about 65°C/h. A distillation conducted more
rapidly than this will serve both to reduce yield by excessive sublimation of P2O5, and increase the possibility of the reagent vessel bursting due to
excessive buildup of HCl and POCl3 pressure inside the reactor, as these do not have sufficient time to percolate through the viscous sodium
metaphosphate medium (the reagents liquefy during the reaction). About 8.2 g (0.053 mol) POCl3 collects in the receiver at the end of the reaction
while the reactor tube loses 9.3 g (the difference is due to losses in the distillation setup), corresponding to a yield of 76% (86% with respect to
reactor weight loss) based on P2O5.
[Edited on 3-7-2020 by DavidJR]
[Edited on 17-3-2021 by zed]
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FrenchChemist
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Registered: 25-1-2021
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Good preparation of POCl3, I did mine with PCl3 which made the process a bit easier.
It is known that having access to pcl3 - pocl3 synthesis may seem strange and wasteful but I did it on a very small scale purely experimental.
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