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Topic: I am looking for mechnism using thionl chloride and DMF.  (Read 1948 times)

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Offline Banny

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I am looking for mechnism using thionl chloride and DMF.
« on: March 11, 2014, 03:12:05 AM »
I experiment below method.

I wast to make pentadecafluoro-octanoyl chloride.

4.3. Synthesis of 2 (pentadecafluoro-octanoyl chloride)
In this study, a convenient method was described for the
preparation of Pentadecafluoro-octanoyl chloride with high
yield (97.1%) from pentadecafluoro-octanoic acid and thionyl
chloride by using DMF as catafyst.

A mixture containing 10 g
(0.024 mol) of pentadecafluoro-octanoic acid 1.7 g
(0.014 mol) of thionyl chloride and 0.5 mL of DMF were
placed into a three-necked flask with a magnetic stirrer, a
reflux condenser and a thermometer.

The reaction solutbn was kept at 70–758C for 2 h.
The resulting product consisted of a yellow liquid upper layer and a white liquid lower layer.
The aqueous phase (i.e., lower layer) was first separated, and then,
distilled under reduced pressure to remove the thionyl chbride.

 Finally, 10.07 g of clear liquid were obtained, that
is compound 2. FTIR spectrum of Compound 2 was shown in
Fig. 7 (curve b). The characteristic peak at 1802 cm1 was
attributed to caibonyl stretching, the appearances of C–F
stretching band of compound 2 at 1250, 1215 and 1149 cm1
were also observed, respectively. These results are in good
agreement with the data published [15]. Elemental analysis
results are listed below: Calcd for C8F15OC1: C, 19.42.
Found: C, 19.38.



Q1, DMF must be added?

Q2, 70~75 degree is right?

Q3, additionally, Should I make aqueous phase? ex)added water?

Q4, After reaction, i don`t observe yellow phase..


Offline AlphaScent

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Re: I am looking for mechnism using thionl chloride and DMF.
« Reply #1 on: March 11, 2014, 10:37:14 AM »
Please, as per forum rules, show your attempt and thoughts on the 4 posted questions and the mechanism.
If you're not part of the solution, then you're part of the precipitate

Offline orgopete

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Re: I am looking for mechnism using thionl chloride and DMF.
« Reply #2 on: March 11, 2014, 04:17:52 PM »

Q1, DMF must be added?

Q2, 70~75 degree is right?

Q3, additionally, Should I make aqueous phase? ex)added water?

Q4, After reaction, i don`t observe yellow phase..

1) It looks like a literature procedure that give 97.1% yield. Why would you want to improve on it?

2) Y

3) It's an acid chloride. Won't it react with water?

If mechanism, start with Vilsmeier-Haack reaction.
Author of a multi-tiered example based workbook for learning organic chemistry mechanisms.

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