Sciencemadness Discussion Board

M-toluic Acid Chlorination

Meltonium - 2-11-2016 at 11:57

I've wanted to make DEET for a while now to explore the chemistry of it; I know it's not cost effective, but whatever. Industrially, it's produced from m-toluic acid. The acid first needs to be chlorinated. Industry uses thionyl chloride, but as I don't really want to go through the process of making this, is there some other way to get the acyl chloride? If I was to bubble HCl through the toluic acid and bind up the water, would that work?

[Edited on 2-11-2016 by Meltonium]

[Edited on 2-11-2016 by Meltonium]

Metacelsus - 2-11-2016 at 14:53

No, probably not. You could try cyanuric chloride.

Alternatively, you could esterify it and try reacting the ester with diethylamine.

[Edited on 11-2-2016 by Metacelsus]

Maroboduus - 2-11-2016 at 17:55

This is not all that different from making LSD. You could always look into clandestine LSD syntheses to get some ideas.

Those guys can't get thionyl chloride, or phosphorus oxychloride, so they make mixed anhydrides to react with the diethylamine.

It's not really my thing, but I recall that one popular method used SO3 in dimethylformamide.
I think acetic anhydride and propionic anhydride have been used as well. (don't remember which solvents though)

The ester and diethylamine approach would be a lot easier. It's surely worth a try first. It must not work with lysergic acid, or they wouldn't have all these other funkier routes. I mean who wants to mess with SO3 if you can avoid it? Ever heard of alpha explosions?

I think diethylamine is considered to be a rather suspicious chemical, and since people make LSD with it the purchase thresholds are probably very low. Probably best to make your own if you don't want people to think you're doing something illegal.

(as a matter of fact, I believe some acid cooks hydrolize DEET to get their Diethylamine rather than going out and buying it)

CuReUS - 3-11-2016 at 03:45

you can do a one pot conversion of carboxylic acid to amide using TCT.
Quote:
Sodium hydroxide (9.75 mL of a 1 M solution, 9.75 mmol) was added to a slurry of 3,5-dichloro-4-methylbenzoic acid (2.0 g, 9.75 mmol) in acetonitrile (40 mL). A 4 C endotherm was observed. The reaction mixture was stirred for 2 h, and then 2,4,6-trichloro-1,3,5-triazine (0.59 g, 3.22 mmol) was added. The resulting slurry was stirred for 2 h and treated with 3-amino-3-methylpentyne (1.34 g of a 74% solution in water, 10.24 mmol); a 3 C exotherm was observed. The reaction was stirred at 23 C for 2 h and worked up as described in the general procedure to give the amide as a white solid (2.09 g, 75%)

http://chemistry.mdma.ch/hiveboard/novel/000372508.html

another way to convert m-toluic acid to DEET -https://www.thieme-connect.com/products/ejournals/abstract/1...

you could also convert the acid to the nitrile(using urea/sulphamic acid),then do this -http://www.sciencedirect.com/science/article/pii/S0040403905...

if you want to avoid using diethylamine,you can make Ν,Ν-diethyl carbamoyl chloride from disulfiram-http://www.tandfonline.com/doi/full/10.1080/0039791090353733...
OTC disulfiram -http://www.pharmacyrx.org/otc-antabuse-over-the-counter.html
and then react diethyl carbamoyl chloride with m-toluic acid to get DEET
Quote:
Preparation of Ν,Ν-Diethyl m-toluamide (DEET)

136 g ( 1 Mole) of m-toluic acid (3-methyl benzoic acid) and 136 g (÷- 127 ml, 1 Mole) N.N-diethylcarbamoyl chloride are taken in a 1 liter two-necked round-bottom flask fitted with air condenser which is placed over a magnetic stirrer. To this, 121 g ( 167 ml, 1.2 Mole) of triethylamine, which is a organic base is added using a pressure-equalizing funnel fitted in the side neck of the round bottom flask at room temperature. After complete addition, the reaction mixture is stirred constantly for 20 minutes at room temperature. The reaction mixture is then treated with 250 ml of water and the two layers are separated. Pure and colourless N.N-Diethyl m-toluamide (DEET) is obtained by vacuum distillation of organic layer which is the product.

Purity of the compound is analyzed using GC-MS which is more than 99.5%. The yield of the product is 186 g (97.5%).

http://www.freepatentsonline.com/WO2013065059A1.html

[Edited on 3-11-2016 by CuReUS]