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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: doublek1229 on March 12, 2010, 08:54:09 AM

Title: Synthesis of Luminol
Post by: doublek1229 on March 12, 2010, 08:54:09 AM
In our organic chemistry lab with synthesized luminol.  I understand the mechanism of the reaction, however I don't understand the purpose of triethylene glycol.  Why would the reaction of 3-Nitropthalic acid and hydrazine require triethylene glycol?  (It says it is "conveniently" carried out in a high boiling point solvent.  Also what does the Na2S2O4 do to the 5-Nitropthalhydrazide to convert it into luminol.  Thanks for any *delete me*
Title: Re: Synthesis of Luminol
Post by: sjb on March 12, 2010, 01:26:37 PM
In our organic chemistry lab with synthesized luminol.  I understand the mechanism of the reaction, however I don't understand the purpose of triethylene glycol.  Why would the reaction of 3-Nitropthalic acid and hydrazine require triethylene glycol?  (It says it is "conveniently" carried out in a high boiling point solvent.  Also what does the Na2S2O4 do to the 5-Nitropthalhydrazide to convert it into luminol.  Thanks for any *delete me*

Why should any reaction require solvent?

What is the difference between 5-nitropthalhydrazide and luminol?
Title: Re: Synthesis of Luminol
Post by: Babcock_Hall on June 07, 2011, 01:06:07 PM
In our organic chemistry lab with synthesized luminol.  I understand the mechanism of the reaction, however I don't understand the purpose of triethylene glycol.  Why would the reaction of 3-Nitropthalic acid and hydrazine require triethylene glycol?  (It says it is "conveniently" carried out in a high boiling point solvent.  Also what does the Na2S2O4 do to the 5-Nitropthalhydrazide to convert it into luminol.  Thanks for any *delete me*
The solvent is just there to control the temperature.  When a solvent is refluxing, it is at its boiling point.  I am not sure about the salt you mentioned.  Do you have a reference to the synthesis?
Title: Re: Synthesis of Luminol
Post by: TMS lover on June 18, 2011, 11:36:33 PM
The reason DEG is used as a solvent is because the temperature the reaction is carried is very high, and as a result, a high boiling point solvent is required, so that while the reaction is being refluxed, the solvent still remains there and it is not fully evaporated.
Title: Re: Synthesis of Luminol
Post by: BobfromNC on June 22, 2011, 04:37:57 PM
The TEG is just a solvent, other solvents should work, but that allows easy heating to high temps.   The Sodium Dithionate is a reducing agent, which reduces the 3-nitro group to a 3-amino group.  This could also be done with hydrogenation, tin or iron in HCl, or a variety of other reducing agents, but Sodium Diothionate is very safe and easy to use, with no heavy metals or major fire hazards.  I did that reaction many years back myself.   Gotta love glowing stuff.  Do you oxidize the luminol with NaFe(CN)6 and hydrogen peroxide?

Bob