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For the chemists: Luminol from a pyro chem


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Posted

I don't have the ability to figure this out. But Luminol looks pretty neat. And it looks like it could be potentially made from something some of us have in our pyro kit - Terephthalic Acid (TPA).

 

Does anyone think they could figure out how to make it from TPA? I think quite a few of us would be interested in making it.

 

Thanks!

Posted

...heating of these acids does not generally lead to cyclic anhydrides, though this conversion sometimes can be accomplished by using special techniques. Upon heating, phthalic acid readily yields phthalic anhydride (with a five-membered ring), but isophthalic and terephthalic acids do not undergo this reaction.

 

source: http://www.britannica.com/EBchecked/topic/458421/phthalic-anhydride

 

phthalic anhydride can be used in the preparation of luminol.

terephthalic acid has carboxyl groups at the 1 and 4 position on the ring while phthalic is at 1 and 2. my access to resources is limited so i'm not sure how or if they can be adjusted. time to dig out the books...

Posted

Interesting .... so what is this Luminol ? I have the phthalic anhydride, and you have my interest.... :-)

Posted

it's one of those things you see in CSI used for finding blood residue. It's so sensitive that you can wash a surface repeatably yet it will still show blood stains.

Posted

From what I've seen it is a 2 part mix that you mix in a spray bottle and spray around and it will actually luminesce and glow in the presence of blood or, I believe more accurately, hemoglobin.

 

The product I've seen glows a faint blue. I'm not sure how long it lasts once mixed. I originally read something about making it from plastic bottles and breaking them down to form terepthalic acid as a step in the process which plastic is about the only commercial/industrial use of TPA. Bluestar is one name brand and can actually be purchased at some hunting stores to track wounded game. Making it would be cool but as with most things, buying it is probably easier.

Posted

You can make luminol using this method from nurdrage

Posted

Interesting .... so what is this Luminol ? I have the phthalic anhydride, and you have my interest.... :-)

 

This will probably be most to your interest then. You know, real scientific procedures and all. There is another prep from phthalimide as well for other interested parties.

 

http://www.orgsyn.org/demo.aspx?prep=cv1p0408

 

There are plenty of preps to get from 3-nitrophthalic acid to luminol. It's a pretty common college chem lab, but most will start from this point. Not a lot will have you make a shitty impure material from gloves. There are listed preps for the dihydro phthalazinedione and luminol itself as well.

 

http://www.orgsyn.org/demo.aspx?prep=CV3P0656

http://www.orgsyn.org/demo.aspx?prep=CV3P0069

 

Anyway, terephthalic acid is unfortunately useless for this. It's the wrong isomer of phthalic acid. Phthalate plasticizers or o-xylene are the most OTC starting materials. Although just purchasing phthalic acid or phthalic anhydride or phthalimide are not that difficult either.

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Posted

all of the articles i find relating to the isomerization of carboxylic acids use very exotic materials and processes. i'm seeing palladium catalysts and supercritical CO2 that requires very specialized equipment. like mumbles said, tpa is probably useless for this. at least in a home lab setting and even if you could do it, it wouldn't be worth the cost and weak yields to justify the trouble you'd have to go through.

Posted
Well I tried to go back and find where I thought I saw mention of TPA in the process but can't find it. It is something I read weeks or even months ago and that popped in my head when I posted. It also seems like I read about breaking down plastic bottles to get the needed chemical which made sense in my head since TPA is used almost exclusively to make plastic (PET?) bottles.
Posted

I read the same thing too ...!!!! It was on one of those lengthy pyro formulation lists right at the end. I have scoured my bookmarks and have concluded the site it was on has changed or updated... sorry I wish I had better news'

Posted

I have seen that but what I saw was producing luminol by breaking down PET bottles. Maybe the chemical obtained wasn't Terephthalic acid and I made the connection in my head thinking TPA was a component. My memory isn't quite what it used to be after high dose chemo and years of pain control.

 

I also think it must have been a different source because I haven't looked at an online pyro formulary in a few years.

 

Oh well, I thought it would be neat if we could run around playing CSI.

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