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Topic: Help identifying FTIR Spectrum  (Read 4594 times)

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Offline Furanone

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Help identifying FTIR Spectrum
« on: July 18, 2014, 11:39:19 PM »
Hi folks,

I am having difficult identifying this compound mainly because I do not have anything like it in my ATR-FTIR spectral database, so I was hoping someone may have seen something like it before and can recognize it.

What I do know about it is it's the brominated powder compound used in hot tubs to help disinfect the tub, and it turns a yellowish color upon dissolving in water.

Thanks for any insight you can offer..

« Last Edit: July 19, 2014, 01:05:42 AM by Furanone »
"The true worth of an experimenter consists in pursuing not only what he seeks in his experiment, but also what he did not seek."

--Sir William Bragg (1862 - 1942)

Offline Furanone

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Re: Help identifying FTIR Spectrum
« Reply #1 on: July 19, 2014, 08:33:51 AM »
I strongly suspect it may be DBDMH (1,3-Dibromo-5,5-dimethylhydantoin) based on the usage as a biocide in water treatment, but if someone could confirm I would greatly appreciate. Structure of DBDMH below:
"The true worth of an experimenter consists in pursuing not only what he seeks in his experiment, but also what he did not seek."

--Sir William Bragg (1862 - 1942)

Offline kriggy

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Re: Help identifying FTIR Spectrum
« Reply #2 on: July 19, 2014, 02:59:55 PM »
Sigma has the spectra for this compound:

http://www.sigmaaldrich.com/spectra/ftir/FTIR001507.PDF

If its yours compound, I cant tell

Offline Furanone

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Re: Help identifying FTIR Spectrum
« Reply #3 on: July 19, 2014, 03:05:21 PM »
Thank you for the link.

No, it is not a match for the spectra as the peaks in the hydrocarbon range 2800-3000 cm-1 are much too large compared to the spectra for my unknown. My search continues....
"The true worth of an experimenter consists in pursuing not only what he seeks in his experiment, but also what he did not seek."

--Sir William Bragg (1862 - 1942)

Offline mjc123

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Re: Help identifying FTIR Spectrum
« Reply #4 on: July 21, 2014, 05:36:23 AM »
And the strongest bands are between 1700-1800 cm-1, while yours are 1600-1700. But just a caution - in ATR, the sample penetration is proportional to the wavelength, therefore is less for high frequencies. Thus, compared to transmission spectra (like the Sigma one), CH stretching bands in ATR are weaker compared to lower frequency bands. But I agree that you ought to see something in your spectrum if those methyl groups are there.

Offline Furanone

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Re: Help identifying FTIR Spectrum
« Reply #5 on: July 21, 2014, 06:41:15 PM »
Thanks folks,

I think it might be sodium bromide as research shows this is also a disinfectant for water although I cannot find a spectrum for sodium bromide online. It kinda makes sense though since there is very little absorbance in the OH stretching 3000-3600 cm-1 or the aliphatic reagin 2800-3000 cm-1 like many other salts; however, I never thought the fingerprint range would be so rich with peaks for such a simple molecule as so many other simple salts I have run have far fewer and broader peaks in the fingerprint region. Maybe this is because it can be in the form NaBr or in the form N2Br2.

If anyone does have a spectrum for sodium bromide I'd appreciate to know if it is a match so I can get some sleep at night  ;D

cheers!

"The true worth of an experimenter consists in pursuing not only what he seeks in his experiment, but also what he did not seek."

--Sir William Bragg (1862 - 1942)

Offline mjc123

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Re: Help identifying FTIR Spectrum
« Reply #6 on: July 22, 2014, 05:06:45 AM »
It's definitely not NaBr; simple ionic salts tend to have few and broad bands. It looks like a complex organic molecule, though the apparent absence of CH stretching bands is puzzling. Could it be a fluoroorganic - I'm trying to think what 1294 could be, apart from C-F. There's definitely OH present - see my remarks on intensity in ATR. What about an amide - there are strong bands between 1600-1700 but not above 1700, and there may be a hint of NH at ca. 3250.

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