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Offline zeshkani

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Re: Unknown
« Reply #15 on: April 18, 2007, 04:06:44 PM »
the mass spec gave me this , and the last peak was at 150, therefore the molar mass is 150
« Last Edit: April 18, 2007, 04:57:34 PM by zeshkani »

Offline zeshkani

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Re: Unknown
« Reply #16 on: April 19, 2007, 12:29:33 AM »
here is the Mass spec

Offline Sam (NG)

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Re: Unknown
« Reply #17 on: April 19, 2007, 04:24:32 AM »
The compound is L-tartaric acid:

IR


So much for disregarding OH groups.

Mass Spec


Peak Table
      14.0       1.1
      15.0       4.3
      17.0       1.4
      18.0       6.7
      19.0      10.7
      28.0       6.8
      29.0      24.2
      30.0      12.8
      31.0      19.9
      32.0       1.4
      41.0       1.4
      42.0      10.8
      43.0      11.1
      44.0      12.2
      45.0      10.6
      46.0       1.2
      47.0       1.5
      49.0       3.1
      58.0      33.5
      59.0      20.3
      60.0       5.9
      61.0       3.3
      69.0       6.8
      70.0      21.3
      71.0       4.1
      75.0       1.7
      76.0     100.0
      77.0      18.0
      78.0       1.0
      87.0       2.3
      88.0      10.6
     105.0      19.8

Mass spec data looks pretty much identical, and i would say that IR was a pretty good match.  (IR and Mass Spec from SDBS)

Offline Dan

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Re: Unknown
« Reply #18 on: April 19, 2007, 07:52:38 AM »
The compound is L-tartaric acid:

Nicely done. This is a bit pedantic, but you can't assert the enantiomer/enantiomeric excess with the data provided so far. However, considering how cheap the L enantiomer is, I expect you're right.

zeshkani, do you have an optical rotation for your sample?
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Offline Sam (NG)

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Re: Unknown
« Reply #19 on: April 19, 2007, 08:27:54 AM »
The compound is L-tartaric acid:

Nicely done. This is a bit pedantic, but you can't assert the enantiomer/enantiomeric excess with the data provided so far. However, considering how cheap the L enantiomer is, I expect you're right.

zeshkani, do you have an optical rotation for your sample?

I was tempted not to put the optical isomer, but the intesities on the MS were different for the dl and d compounds (not that i'm suggesting that you can tell these things by MS, but rather that i offered the closest match).

Offline zeshkani

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Re: Unknown
« Reply #20 on: April 19, 2007, 01:58:48 PM »
no but i can get the optical rotation, ill post as soon as i get it, and thanks for all the help

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