Attachment: Methyl Orange.pdf (210kB) This file has been downloaded 2017 times
bfesser - 28-7-2009 at 15:25
Yet another excellent writeup from your group. Have you taken the melting point of your isolated solid?Ozonelabs - 28-7-2009 at 15:27
We would have done, however it decomposes before melting. bfesser - 28-7-2009 at 15:31
Could you seal a capillary and take the decomp point, at least? Please? Ozonelabs - 28-7-2009 at 15:33
Sure, we'll grab an IR spec too.
Picric-A - 28-7-2009 at 15:43
Nice clear write-up on a extremly usefull indicator!
well done!Klute - 28-7-2009 at 15:47
Very nice! It's always a pleasure to read such report, good organic chemistry!
ANy other color indicators in view? Phenolphtaleine?Ozonelabs - 28-7-2009 at 15:55
We are exploring azo-dyes.
PDF's upcoming are Luminol (Finally!), Oxalyl Chloride and then swern oxidation, Dichloromethyl methyl ether (far future), Vilsmeier Haack
formylation.
[Edited on 28-7-2009 by Ozonelabs]pantone159 - 28-7-2009 at 19:48
A similar reaction should give methyl red, using anthranilic acid instead of sulfanilic acid, unfortunately this is much more a problem to get! The
prep in Vogel also looks more finicky than for methyl orange.
Do you know of any other azo dyes to make with dimethylaniline? Ozonelabs - 29-7-2009 at 01:16
We have around a kilo of Anthranilic acid- Methyl Red is next on the list. Nernst - 29-7-2009 at 04:19
Thanks! I'm fascinated by dye chemistry, partly because that was the beginning of the entire organic chem industry.
But I don't enjoy the bleach showers I have to take every time I synthesize a dye.
JohnWW - 29-7-2009 at 08:33
I remember synthesizing some methyl orange years ago, in my stage 2 Chemistry (Organic) laboratory class. I am not sure what became of the product.a_bab - 31-7-2009 at 23:25
Can't wait for luminol/oxalyl chloride.Ozonelabs - 7-8-2009 at 04:41
The decomp point was 314 C through an open tube.
This was in line with a 99.9% AnalR sample from BDH. Magpie - 27-10-2010 at 21:08
Here's the results of my synthesis of methyl orange using homemade sulfanilic acid and N,N-dimethylaniline. I followed the procedure of Brewster,
circa 1962. Basis was 5g of sulfanilic acid and 3mL of N,N-dimethylaniline.
I used a 600mL beaker on a magnetic stirrer. The procedure was pretty much the same as that of Ozonelabs except HCl was used instead of acetic acid.
Also, 30g of salt (NaCl) was added to the final mix just prior to crystallizing the product. A 95% ethanol wash was used on the Buchner funnel.
The expected yield was 8-9g per Brewster. My yield was 2.14g, or 22.6%, which is quite disappointing, and without apparent explanation. It seemed
like a lot of the product went right through the Buchner funnel paper.
