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Topic: substitute for methanesulfonic acid  (Read 3964 times)

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Offline chpa12

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substitute for methanesulfonic acid
« on: February 16, 2010, 07:34:04 PM »
I have to make two fluorescent dyes from resorcinol, 1-6 dihydroxynapthalene and trimellitic anhydride. I have to dissolve the resorcinol in methanesulfonic acid and add trimellitic anhydride then heat to 80-85 degrees over night to give the compound in the attachment as a crude yellow solid (R=H in the diagram).

There isn't any methanesulfonic acid left in the lab and it would take around a week to arrive so i'm looking for an acid that would work in its place, i know there's trifluoromethanesulfonic acid available. would the triflic acid be suitable? i know it's a much stronger acid in comparison to methanesulfonic acid (pKa of -15 compared to -2 i think). i'm not really an organic chemist so i'm pretty unsure of this stuff. any suggestions are much appreciated, thanks.

Offline orgopete

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Re: substitute for methanesulfonic acid
« Reply #1 on: February 16, 2010, 09:31:20 PM »
I am reminded of the conflicting adages, "Five minutes in the lab will save you five days in the library," or "Five minutes in the library will save you five days in the lab" (or something like that). This is what I would do if I had those reagents and wanted to know if it worked before I ordered the reagents, I'd just try it.
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Offline chpa12

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Re: substitute for methanesulfonic acid
« Reply #2 on: February 17, 2010, 12:09:08 PM »
yeah that's what i was hoping to do,but the triflic acid has also run out and the p-toluenesulfonic acid is much too weak,thanks for the reply.

Offline orgopete

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Re: substitute for methanesulfonic acid
« Reply #3 on: February 17, 2010, 02:05:41 PM »
If you don't want to give up as easily, you just might try something anyway. Look as this 90% yield of fluorescein, http://www.patentstorm.us/patents/5637733/description.html

An acid can help. Add some sulfuric acid.
Author of a multi-tiered example based workbook for learning organic chemistry mechanisms.

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