[Ion.liq]

Hi,
I need to prepare pyridinium acetate. I thought that I use pyridine and glacial acetic acid mixing togehther. But I'm not sure this reaction. I think, that acetic acit may be too week to protonate pyridine. What do you think?

[clarkstill]

pKa of AcOH is about 5, as is the pKa of protonated pyridine, so at equilibrium you'd expect around a 1:1 mixture. Could you live with it being trifluoroacetate and use TFA?

Otherwise, you could generate the HCl salt of pyridine, then treat it with silver acetate - it should precipitate AgCl and generate pyridinium acetate.

(there might be other ways, this is just off the top of my head)

[AWK]

Hi,
I need to prepare pyridinium acetate. I thought that I use pyridine and glacial acetic acid mixing together. But I'm not sure this reaction. I think, that acetic acid may be too week to protonate pyridine. What do you think?

This works. Add the stoichiometric amount of acetic acid dropwise to dry pyridine, and ionic protic liquid is ready to work up to 110°C.

[Ion.liq]

pKa of AcOH is about 5, as is the pKa of protonated pyridine, so at equilibrium you'd expect around a 1:1 mixture. Could you live with it being trifluoroacetate and use TFA?

Otherwise, you could generate the HCl salt of pyridine, then treat it with silver acetate - it should precipitate AgCl and generate pyridinium acetate.

(there might be other ways, this is just off the top of my head)

I thought about conversion Cl anion to acetic anion but I wanted use ion exchange resin Dowex Monosphere but this proces is time-consuming 

This works. Add the stoichiometric amount of acetic acid dropwise to dry pyridine, and ionic protic liquid is ready to work up to 110°C.

How long I must heating this mixture in 110°C?

[AWK]

No heating is needed. But you may use this mixture for synthesis up to 110°C (b.p. 115°C).
Tetrahedron 68 (2012) 4813-4819
doi:10.1016/j.tet.2012.03.114

[Ion.liq]

No heating is needed. But you may use this mixture for synthesis up to 110°C (b.p. 115°C).
Tetrahedron 68 (2012) 4813-4819
doi:10.1016/j.tet.2012.03.114

Thank you very much for helping me