Guys, do not fall for the cult of the holy reflux. Refluxing has no worth in itself except for the illusion of something happening which it creates.
With H2SO4 and Oxalic acid (best) but Phosphoric Acid and about any organic acid like Acetic or Formic or Citric work one gets next to quantitative yields if one heats up the mixture slowly over two hours to NOT MORE then 95 °C, holds it there for 30 minutes and then let it cool down. Add a small amount of solvent other then DCM (Toluene, Xylene, Ether) as organic acid may fall out and so collecting from top is advised. Petrol Ether 40/60 can be used and not much is needed but you get THREE layers in the end: Top layer is Pet-Ether with P2P dissolved. Middle layer is P2P with Pet-Ether dissolved*. And below is the acid mix (which can be re-used btw. without problems).
*Sounds funny but thats how it is: Both, Pet-Ether and P2P dissolve some of the other one but thex are not freely miscible. And so you get the three layers which drove me next to nuts already a long time ago. Until I figured this out.......
200 g Oxalic Acid Dihydrate
300 ml Water
100 ml H2SO4 37% (battery acid)
not all Oxalic Acid will dissolve - no problem
With this one can process a minimum 200 ml 20230 red oil
Really strong stirring all the time is needed.
The water/acid mix can be re-used.
Not over 95 °C gives light yellow P2P directly without steam or other distillation.
When you use a sep-funnel you best separate as long its still hot and the oxalic does not drop out.Or you put it in a beaker in the freezer with the bottom of the beaker touching the cold so it starts to crystallize from there. If you do this you need no solvent at all, the acid and watere crystallizing from the bottom will drive the P2P to the top and you can just pour it out after two or three hours and NO P2P will be left back.
I did a lot of work on this one, lol
With H2SO4 and Oxalic acid (best) but Phosphoric Acid and about any organic acid like Acetic or Formic or Citric work one gets next to quantitative yields if one heats up the mixture slowly over two hours to NOT MORE then 95 °C, holds it there for 30 minutes and then let it cool down. Add a small amount of solvent other then DCM (Toluene, Xylene, Ether) as organic acid may fall out and so collecting from top is advised. Petrol Ether 40/60 can be used and not much is needed but you get THREE layers in the end: Top layer is Pet-Ether with P2P dissolved. Middle layer is P2P with Pet-Ether dissolved*. And below is the acid mix (which can be re-used btw. without problems).
*Sounds funny but thats how it is: Both, Pet-Ether and P2P dissolve some of the other one but thex are not freely miscible. And so you get the three layers which drove me next to nuts already a long time ago. Until I figured this out.......
200 g Oxalic Acid Dihydrate
300 ml Water
100 ml H2SO4 37% (battery acid)
not all Oxalic Acid will dissolve - no problem
With this one can process a minimum 200 ml 20230 red oil
Really strong stirring all the time is needed.
The water/acid mix can be re-used.
Not over 95 °C gives light yellow P2P directly without steam or other distillation.
When you use a sep-funnel you best separate as long its still hot and the oxalic does not drop out.Or you put it in a beaker in the freezer with the bottom of the beaker touching the cold so it starts to crystallize from there. If you do this you need no solvent at all, the acid and watere crystallizing from the bottom will drive the P2P to the top and you can just pour it out after two or three hours and NO P2P will be left back.
I did a lot of work on this one, lol
↑View previous replies…
- By w2x3f5
indicate the yield of the substance p2p please.
do you have red oil? strangely, I had yellow oil under the same number.
do you have red oil? strangely, I had yellow oil under the same number.
↑View previous replies…
- By OrgUnikum
How does it smell? But anyways it should be light yellow to golden at most (lighter color is better), it is really quite easy, red oil + water + oxalic acid + 38% H2SO4, heat to a max. of 95°C hold at this temp for some time and let cool down. STRONG STIRRING is most important! Until it is finished and let cool down of course.
Theoretical max. yield is about 45g P2P from 100g 20320-59-6, my yield was never less then ~40g of high quality P2P from 100g starting material after I had figured the method out, which is btw. very close to the method the inventor of the synthesis used and published in the article he wrote about it.
Theoretical max. yield is about 45g P2P from 100g 20320-59-6, my yield was never less then ~40g of high quality P2P from 100g starting material after I had figured the method out, which is btw. very close to the method the inventor of the synthesis used and published in the article he wrote about it.
