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 on: Today at 08:00:06 AM 
Started by wanzharif - Last post by Enthalpy
Welcome, wanzharif!

My first thought is that the biggest flame or explosion risk doesn't come from the residue, but from the gases evolved when the residue is created.

Castor oil isn't expect to decompose at 160°C.

Then, if you want to determine a flash point, the simplest way is to bring a sample of your tar to the chemistry lab of a university. If not, try to reproduce the standard method:

 on: Today at 07:27:21 AM 
Started by wildfyr - Last post by wildfyr
I actually don't care too much at this point about the substitution pattern. It could be something worth investigating, but this is for an application in a polymeric material where I don't think it will matter. I'd rather block the para position and simplify synthesis. My first pathway was just based on the starting material I had.

 on: Today at 06:49:24 AM 
Started by kateoik - Last post by kateoik
Two deactivates group like CN and CHO in position 1,4 what product will give me in an aromatic sulfonation?

 on: Today at 06:49:02 AM 
Started by wildfyr - Last post by Dan
Why would you go with 3-aminophenol? the 4 allows me to block the para position and ensure the best regioselectivity.

Because the N and O are meta to each other in the product, not para - wouldn't 4-aminophenol give you 2-hydroxy-5-(sulfonamide) benzaldehyde (i.e. not your target)? Or have I misunderstood something?

 on: Today at 06:22:09 AM 
Started by kea1118 - Last post by sjb
Perhaps I am wrong. Methoxy ion should be strong enough to pluck that alpha hydrogen.

I'd think so - having carried out work similar to that described in WO2007054254A1 in the past.

 on: Today at 06:17:37 AM 
Started by Qaiphyx - Last post by Qaiphyx
I suppose I should correct myself I meant arsenic trioxide not trichloride, I was assuming that the arsenic impurities would react with hydrochloric acid which is inaccurate.

If anyone has any input on this please let me know. Thanks.

Also if anyone could correct my math on how much arsenic that is per ounce of tin it would be appreciated. But what I have come up with is that there are 28000 milligrams per ounce, and thus at .008% weight it would be 2.2mgs per ounce, correct?

 on: Today at 05:39:53 AM 
Started by khaza - Last post by Babcock_Hall
What about testing the membrane in an ultrafiltration experiment with PEGs of various molecular weights?

 on: Today at 05:09:56 AM 
Started by ervays - Last post by Borek
Without a reference you can measure voltage difference, but not the absolute value.

 on: Today at 05:06:54 AM 
Started by catarina1998 - Last post by Borek
I didnt understand your answer ???

Don't worry, it was a spammer quoting abstract of some random paper on the subject ( J. Chem. Soc., Perkin Trans. 2, 1983, 1079-1086).

 on: Today at 04:30:21 AM 
Started by fa911662 - Last post by Babcock_Hall
P. 230 of Robyt and White's textbook states, "The color yields for the different amino acids, however, are not the same and must be taken into consideration when different amino acids are being quantitatively determined."  Sounds to me that even if you were comparing, say alanine and leucine, you could not make a comparison of the two, unless you prepared a standard curve for each.

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