Sciencemadness Discussion Board

preparation of salicylic acid from anthranilic acid

falala - 29-1-2009 at 06:57

how can SA be synthesized from AA?
by diazo replacement? how's that?

any help will be really appreciated! thank you!

[Edited on 29-1-2009 by falala]

sparkgap - 29-1-2009 at 07:17

Seriously? I know a number of people who'd rather use the anthranilic acid for other purposes as it is not too easy to come by, and also because salicylic acid can easily be had with no fuss.

sparky (~_~)

falala - 29-1-2009 at 07:22

that's the thing. they want us to synthesize SA with AA
the reaction's diazotization and hydrolysis. do you know the intermediates of this reaction?

panziandi - 29-1-2009 at 07:45

Anthranilic acid would be diazotised with sodium nitrite/hydrochloric acid mixture at 0*C, the solution would then be hydrolysed by increasing the temperature. If you look up a reation for making a phenol from a diazonium compound and follow that but with your reactants.

Google "reactions of diazonium compounds" and do some reading. Look in the library section of this site (www.sciencemadness.org) specifically look up experiments in Practical Organic Chemistry by A. I. Vogel or take a look on www.orgsyn.org for diazonium reactions.

Research is an important technique to learn, just as important as experimental technique.. try this before you get attacked for incompetence by some older members of this board! ;)

falala - 29-1-2009 at 08:07

I've done my research and I know that SA is prepared by common rxns such as oxidation from aglycone and kolbe rxn with phenol. no reference shows AA--> SA very well, that's why I'm trying to ask.

thanks anyway

sparkgap - 29-1-2009 at 08:12

As to diazotizing anthranilic acid (even though I still think better things can be done with diazotized anthranilic acid), do look at this. Presumably, carefully warming the aqueous solution should give you salicylic acid.

sparky (~_~)

falala - 29-1-2009 at 08:25

thanks! :D

panziandi - 29-1-2009 at 08:45

Well what I'm saying is you research the GENERAL reaction that converts an aromatic amine to a phenol. You then have your answer!

For example: http://www.orgsyn.org/orgsyn/prep.asp?prep=cv1p0404 details preparation of m-nitrophenol from m-nitroaniline. Follow this procedure but using anthranilic acid instead of m-nitroaniline and work up the product with an acidification and extraction with diethyl ether etc.

falala - 29-1-2009 at 18:42

right. thanks. someone gave me that link too. thanks again

Sauron - 29-1-2009 at 19:02

I completely agree that salicylic acid is a whole lot easier to come by than anthranilic acid.

So the question ought to be how to make anthranilic acid from salicylic acid and not the other way round.

chemrox - 29-1-2009 at 19:48

Use the AA for something more fun and extract the SA from headache tablets.

sparkgap - 29-1-2009 at 19:58

I'm inclined to think that the "they" alluded to in the third post in this thread must be some academic institution; no one else can be that impractical. :P

sparky (~_~)

Sauron - 30-1-2009 at 06:55

It does sound like homework or an open book exam question, doesn't it?

Intermediates in diazotization?

Sophomore, first year of organic course?

Hard for me to judge, I'm 40 years beyond all that, I despair when I am told of how they teach undergrads these days.

panziandi - 30-1-2009 at 07:26

Well I thought it looked like a pre-lab exercise that is why I gave a vague outline and suggested some sources to take a look at for the general procedure that he could adopt and interpret to this particular and specific example...rather than spoon feeding someone their homework answers.

sparkgap - 30-1-2009 at 07:33

Quote:
Originally posted by Sauron
I despair when I am told of how they teach undergrads these days.


You say that; I on the other hand despair of having had to saponify concentrated grape flavoring because #@$&*! company would not sell the acid without a fair amount of paperwork back in the day (I never did like supposedly needless extra steps). I almost wept at reading his proposal.

sparky (~_~)

Sauron - 30-1-2009 at 10:22

You mean, to get methyl anthranilate?

Anthranilic acid is not that hard to make, from phthalimide, and phthalimide is dead easy to make from phthalic anhydride and urea, or ammonium hydroxide (conc) or ammonium carbamate.

If I were to do it again I'd judt buy the potassium phthalimide.

falala - 3-2-2009 at 03:36

Quote:
Originally posted by sparkgap
I'm inclined to think that the "they" alluded to in the third post in this thread must be some academic institution; no one else can be that impractical. :P

sparky (~_~)


yeah it's because i'm in high school.

falala - 3-2-2009 at 03:38

Quote:
Originally posted by Sauron
It does sound like homework or an open book exam question, doesn't it?

Intermediates in diazotization?

Sophomore, first year of organic course?

Hard for me to judge, I'm 40 years beyond all that, I despair when I am told of how they teach undergrads these days.


no, no. I'm in my last year of high school. We're supposed to perform this in our lab class next week. :D

Sauron - 3-2-2009 at 03:42

In what country?

Nicodem - 5-2-2009 at 01:02

Falala, the diazonium zwitterion prepared from anthranilic acid decomposes to benzyne (and this immediately further) on heating: http://sciencemadness.org/talk/viewthread.php?tid=8898
Please, next time use the search engine before posting. Also when opening new threads without providing any references, please do so in the Beginnings section where I'm moving it anyway.