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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: lukas.stib on April 23, 2021, 01:49:50 AM

Title: 85% solution of orthophosphoric acid as catalyst
Post by: lukas.stib on April 23, 2021, 01:49:50 AM

Hello chemists,

can I use an 85% orthophosphoric acid solution as a catalyst in the Fischer esterification? I know H2SO4 is used, but I don't have it.

Thank you, Lukáš.

Title: Re: 85% solution of orthophosphoric acid as catalyst
Post by: rolnor on April 23, 2021, 02:19:03 PM

No, its not strong enough.

Title: Re: 85% solution of orthophosphoric acid as catalyst
Post by: Babcock_Hall on April 23, 2021, 02:31:49 PM

I wonder whether or not the amount of water in phosphoric acid is also a problem.

Title: Re: 85% solution of orthophosphoric acid as catalyst
Post by: rolnor on April 23, 2021, 05:09:21 PM

If you look at pKa its a big differens, water does not make it any better for sure. -2.8 for H2SO4 and 2.15 for H3PO4

Title: Re: 85% solution of orthophosphoric acid as catalyst
Post by: lukas.stib on April 24, 2021, 09:44:07 AM

So this means that I don't have to use phosphoric acid for F. esterification at all...