Sciencemadness Discussion Board

MCA sulponation

pawan - 27-4-2009 at 21:40

Sir,
I am trying to understand the product when I do sulphonation of meta chloro aniline using chlorosulfonic acid.
Some books are stating that we get 1-amino 3-chloro sulphonic acid while some are stating that we get 1-amino 3-chloro sulfonyl chloride.

How it is possible without using SOCl2 to get second derivative.

Nicodem - 27-4-2009 at 23:21

Please state the references claiming different products, particularly since the names of the products you stated make no sense (how can you have 1-substituted benzenesulphonic acid or chloride?). Without knowing the experimental, how is anybody to guess what product you get?

You don't need thionyl chloride to transform a arylsulfonic acids into a arylsulfonyl chlorides. PCl<sub>5</sub> works better.

Also, when opening threads without stating references or by asking unanswerable questions, please do so in the Beginnings section where this is tolerated. Otherwise, like in this case, I will move the thread there anyway.

PS: It is "sulfonation" and not "sulponation" or "sulphonation". Using proper spelling is crucial when doing a literature search. The electrophilic aromatic substitution using chlorosulfonic acid is called "chlorosulfonation".

Sauron - 28-4-2009 at 00:15

Thr ptoduct depends on the workup.

Cl-SO2-OH reacts at the -OH with the aryl compound end and gives the sulfonyl chloride

If you hydrolyze that during workup uou have the free sulfonic acid.

No mystery.

pawan - 28-4-2009 at 00:51

Sorry sir,
I am a student & doing my summer training in a plant where company is producing this intermediate product. I may be wrong in interpreting the name.

The product is having SO2Cl group at one location on benzene ring, at ortho position to it is chlorine & at para position is NH2 group - Yes so it becomes 2-chloro-4-amino sulfonyl chloride. Then they do amination to convert it to sulfonamide.

The reference I found from Kirk Othmer Vol-6 but could not understand. It is given on page-86 Vol-6. Both the reactions of below type are there

Ar-H + ClSO3H = Ar-SO3H + HCl
Ar-H + 2 ClSO3H = Ar-SO2Cl + H2SO4 + HCl

Situation

1. Company is using 8 times of theoretical value of chlorosulfonic acid to do first step.

2. Then they are using SOCl2 gas to make the above mentioned sulfonyl chloride.

My actual question is?
1. Do they need so much excess chlorosulfonic acid for meta chloro aniline (They are adding MCA in CSA)

2. Still they are using SOCl2 to make sulfonyl chloride while according to second reaction only CSA is sufficient if it is in excess.

3. If I do other way Add CSA in MCA then what will be the CSA consumption generally?

Thanks sir for your help.
pawan



Paddywhacker - 28-4-2009 at 02:36

Quote: Originally posted by Nicodem  
...

PS: It is "sulfonation" and not "sulponation" or "sulphonation". Using proper spelling is crucial when doing a literature search. The electrophilic aromatic substitution using chlorosulfonic acid is called "chlorosulfonation".


Please ignore the language imperialism. "sulphonation" is quite acceptable. Some people take the spelling simplifications introduced by Noah Webster as gospel.

Nicodem - 28-4-2009 at 10:29

Quote: Originally posted by Paddywhacker  

Please ignore the language imperialism. "sulphonation" is quite acceptable. Some people take the spelling simplifications introduced by Noah Webster as gospel.

I'm afraid you will not get far if searching the literature for "sulphonation". For example, searching the ACS journals with this keyword gives exactly 0 articles containing this word in the tittle and 55 hits for this keyword anywhere in the article text (and if you check you will note the authors mostly mispelled it, because you can find "sulfonation" in the same article as "sulphonation"). The same search for "sulfonation" gives 187 hits for containing in the tittle and 3900 hits for anywhere in text. This is just an example on how important it is to use proper chemical nomenclature when doing a literature search.
But anyway, "sulphate" and all its derived words come from UK English and are nowadays not allowed to be used any more. The IUPAC Blue book now made "sulfate" and its derived words the terms to be used in chemical nomenclature: http://www.acdlabs.com/iupac/nomenclature/93/r93_503.htm

DJF90 - 28-4-2009 at 11:02

Nicodem is right. "Sulphur" is an english spelling (incorrect if I may add), and "sulphate" etc. branch from it. Now I'm at uni and I've noticed how everything is spelt with the "f" instead of the "ph". At first I was a little reluctant to change to sulfate etc. but then I realised how silly "Sulphuryl" looks when I wrote it and hence adopted the IUPAC accepted nomenclature.

Paddywhacker - 28-4-2009 at 12:45

Great thread hijack ;-)

When you say "sulphur" is the English spelling you are correct. It is the English-speaking world's spelling. Only America and it's clients use Noah Webster's spelling.

You do understand. When Webster simplified English spelling, he took America out of the mainstream.

And Nicodem, using ACS to support American spelling is rather disengenuous.

Edit: attached "sulph" lines filtered from local chemical catalogue.

[Edited on 28-4-2009 by Paddywhacker]

Attachment: Ajax.txt (15kB)
This file has been downloaded 1284 times

Nicodem - 28-4-2009 at 13:03

You seem to fail to comprehend the authority IUPAC has over chemical nomenclature. No chemist care about any Noah Webster (I did not even knew who this guy was before I checked due to your mention), but he is bound to obey the rules set out by IUPAC. This is not something that has to do with dictionaries, not even with the English orthography (which is anyway a pain in the ass due to its hybrid nature even without considering its minor differences between the UK and USA). It only has to do with the Blue book, the highest authority in organic nomenclature.
And if you think it was disingenuous to use ACS journals as an example, check the RSC journals and you will see there is not a single paper published with "sulphonation" in the tittle since the ban on its use. You get 91 hits but they are all old papers from before 1990's.

Edit: Just to dehijack the thread...
Quote: Originally posted by pawan  
Sorry sir,
My actual question is?
1. Do they need so much excess chlorosulfonic acid for meta chloro aniline (They are adding MCA in CSA)

2. Still they are using SOCl2 to make sulfonyl chloride while according to second reaction only CSA is sufficient if it is in excess.

3. If I do other way Add CSA in MCA then what will be the CSA consumption generally?

Thanks sir for your help.
pawan

1. I'm sure they optimized their process since nobody likes to throw money and chemical waste out of the window. So the logical answer is yes. Besides that is not such a terrible excess for chlorosulphonic acid.

2. You never described the process they use so it is kind of naive to expect a reasonable answer from anybody here. Why don't you ask your boss there?

3. I don't think it would make much of a difference except for the exothem from neutralization which might cause charring if the order of addition is reversed, because you would have a lower initial amount of the reaction mixture and thus more problems with heat dissipation.

PS: Please do not use acronyms. Instead use chemical names or comprehensible rational formulae. For example, "MCA" means completely nothing to us. On the the other hand "CSA" has a use in organic synthesis as the acronym for camphorsulfonic acid, a widely used acid for chiral resolutions. But you seem to use it for chlorosulfonic acid aka ClSO3H (you see, it is not difficult to use a full name for a chemical or its rational formula).
Also, since you are communicating through an internet forum you should not use hierarchical titles like Sir or Mr. and such. It just looks too weird and humiliating. It makes me nervous every time I see it. Otherwise, welcome to the forum.

[Edited on 28/4/2009 by Nicodem]