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Author: Subject: paradiclorobenzene - possible degradation of
Nicodem
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[*] posted on 12-8-2013 at 07:06


Quote: Originally posted by Nicodem  
Under rather extreme conditions it can even be acylated via the Friedel-Crafts reaction (for example with phthaloyl chloride and AlCl3 at 120°C, or acylation with MeCOCl at 150°C!).

An example of the Friedel-Crafts benzoylation of 1,4-dichlorobenzene can be found at Synthetic Pages: 2,5-Dichlorobenzophenone (DOI: 10.1039/SP584).




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[*] posted on 20-10-2017 at 15:23
Synthesis of substituted aromatics from paradichlorobenzene


Recently, while going through some old boxes, I found a bunch of old bottles of pesticides. I also found some moth killing crystals that claim to be pure paradichlorobenzene. They seemed just too good not to use for some chemistry, the crystals are clear and appear to be pure, so I thought I'd have a go at synthesizing some double substituted aromatics. (I don't know anything beyond very basic organic chemistry). Anyhow, perhaps someone here can help. I am now unsure what to make (no guaiacol), but can I convert the paradichlorobenzene to a bromo or iodo compound?

Edit: removed mentions of guaiacol synthesis, for obvious (but apparently not obvious enough to me) reasons.

The can ;):


IMG_0086.JPG - 1.2MB IMG_0087.JPG - 1MB

[Edited on 21-10-2017 by Elemental Phosphorus]
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[*] posted on 20-10-2017 at 16:17


Right, I'm a complete idiot. I'll have to settle for something para-substituted then. How could I have made such a lapse as to suggest the synthesis of an ortho-substituted compound. But perhaps it could be converted to the iodide by treatment with sodium iodide (of any other alkali iodide) in acetone solution. Anyway I'd honestly have this thread deleted at this point.

Edit: The route with sodium iodide I described will not work. The reaction only works when the organic iodide is insoluble in the reaction solvent, but the chloride is. Also, it should not work on compounds where the chlorine is on the benzene ring directly and not a side chain.

[Edited on 21-10-2017 by Elemental Phosphorus]
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clearly_not_atara
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[*] posted on 20-10-2017 at 17:42


:p I think you could substitute the chlorines with something, but because they're chlorines, you'd need a copper catalyst and ligands. If this sounds like your cup of tea, keep at it, but if making pyridine or 2,2'-bipyridine or 1,10-phenanthroline or maybe ethyl nicotinate all sounds like too much trouble, then you may not find success.

The first hydrolysis should be pretty fast, so maybe you could make p-chlorophenol or p-chloroanisole?

http://www.orgsyn.org/demo.aspx?prep=cv5p0102

I wonder if Urushibara nickel can be used?

EDIT: No Finkelstein on aryl halides, sorry.

EDIT2: The diol used here:

http://pubs.acs.org/doi/abs/10.1021/jo900438e?journalCode=jo...

can be prepared by the rxn of maleic anhydride with anthracene and reduction with LAH

Someone did it with palladium and sodium methoxide under PTC:

http://onlinelibrary.wiley.com/doi/10.1002/anie.201000576/fu...

I've looked high and low for substitutions of aryl chlorides and the only practical methods go by the intermediacy of organometallic reagents.

EDIT3: Let's follow up on the organometallic for a minute. Anhydrous chromium (II) salts and nickel halide catalyst make aryl Nozaki reagents:

http://en.wikipedia.org/wiki/Nozaki_reaction

These condense with aldehydes or maybe some other moieties of interest...

[Edited on 21-10-2017 by clearly_not_atara]
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[*] posted on 20-10-2017 at 19:14


Chemically, p-dichlorobenzene is not useful for very much because of its lack of reactivity. That being said, however, it can be mononitrated which then renders the chlorine ortho to the nitro group readily displaceable. For example, the chlorine can be displaced by amines, sulfur (eg, mercaptans) and oxygen (eg alcohols). If you are interested, I can dig up a reference to the nitration which is in an undergrad lab manual that I have stashed somewhere. You could also do a google search on the nitration of p-dichlorobenzene and find the procedure.

Another use if your sample is pure enough is for molecular weight determination by melting point lowering. This was a pretty standard procedure and a description of it can be found in older organic qualitative analysis textbooks. Its not used anymore since mass spec is so easily available.

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Nicodem
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[*] posted on 21-10-2017 at 06:22


Actually, I searched for mononitration of paradichlorobenzene, and I didn't find much, so the reference would be appreciated.

Edit: I found a procedure. I am not sure if it is similar to yours, but I can't imagine it is much different, so here it is (from PubChem):

Nitration of 1,4-dichlorobenzene with mixed acid at 35-65 deg C results in a 98% yield of essentially pure 1,4-dichloro-2-nitrobenzene.
Booth G; Ullmann's Encyclopedia of Industrial Chemistry. 7th ed. (1999-2012). New York, NY: John Wiley & Sons; Nitro Compounds, Aromatic. Online Posting Date: June 15, 2000

[Edited on 21-10-2017 by Elemental Phosphorus]

[Edited on 21-10-2017 by Elemental Phosphorus]
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[*] posted on 21-10-2017 at 21:02


For the nitration procedure of p-dichlorobenzene and some reactions of the nitro compound search on Google:

"Fundamental Processes of Dye Chemistry" for a free download.

Examine pages 108ff for the pertinent information. Actually, the entire book is quite interesting and useful.

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[*] posted on 22-10-2017 at 00:09


Quote: Originally posted by Elemental Phosphorus  
Actually, I searched for mononitration of paradichlorobenzene, and I didn't find much, so the reference would be appreciated.

You must have misspelled something. It took me 1 minute to find the articles for mono- and dinitration using the forum search engine:

mononitration of p-dichlorobenzene
dinitration of p-dichlorobenzene




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[*] posted on 23-10-2017 at 12:00


Alright, so I nitrated 5 grams of paradichlorobenzene in mixed acid at about 50-100 degrees Celsius (I accidentally went a little overboard on the heating) for about an hour. I got a yellow, water insoluble product. I'll have to weigh it and do some tests on it soon. Anyway, here are some photos of the reaction.

The starting paradichlorobenzene:


The reaction itself:


The final product:

IMG_0088.JPG - 1.2MBIMG_0100.JPG - 1.4MBIMG_0106.JPG - 1.1MB
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[*] posted on 23-10-2017 at 15:49


Intergalactic_Captain made some of this back in 2005 and reported it to be very irritating to eyes mouth and nose.
He got a little on his hands and it was transferred to his face later inadvertently.

So be careful to wash up and you might want to consider gloves.

I just saw this one report, so it could be erroneous.

It's in the
paradichlorobenzene -> chlorobenzene?
thread



[Edited on 23-10-2017 by SWIM]
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[*] posted on 25-10-2017 at 07:11


Once you have nitrated it (p-DCB) the chlorine in the ortho position to the nitro group should be activated towards substitution as is the case with 2,4 dinitrochlorobenzene, though I suspect its not quite as active but enough to replace the ortho Cl with OH, SH or NH2 groups. The chloro group in the para position can then be removed by hydrogenation (see US 4207261 Preparation of o-phenylenediamine from p-dichlorobenzene).

It may also be possible to reduce the nitro group to give 2,5-dichloroaniline and then nitrate this further, though the result may be a mixture of isomers and mono and dinitro substituted compounds. Someone with reaxsys may want to have a look and see if they can find a reference to such a nitration.

I have done a bit more digging and found a Chinese patent that claims that 2,5-dichloroaniline can be nitrated as its acetylated derivative to give the 4-nitro aniline that is then reduced to 2,5-dichloro-p-phenylenediamine.

I also found a University of Iowa dissertation on the uses of p-dichlorobenzene from 1919. So most of the reactions are reasonably repeatable for a well equipped amateur apart from the ones that require oleum but you may be able to get away with alkali nitrate and excess conc sulphuric acid at higher temperatures.

Elsewhere on this forum I saw a reference to an Org Synth reaction for dechlorinating chlorobenzene to benzene. Has anyone ever tried this with pDCB?

Attachment: Manufacture of 2,5-dichloro-p-phenylenediamine Chinese Patent CN 1974540 B.docx (20kB)
This file has been downloaded 85 times

[Edited on 25-10-2017 by Boffis]

Attachment: A study of paradichlorobenzene IowaUni Dissertation J H Crowell 1919.pdf (4.8MB)
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[*] posted on 25-10-2017 at 10:04


Yes, I would like to substitute the ortho chlorine with an alcohol. Perhaps someone knows of a procedure? Also in response to SWIM, I do use gloves when conducting most reactions, so I did not experience any irritation. Unfortunately, I am not set up to hydrogenate, so that's not an option.
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[*] posted on 1-3-2018 at 14:41


Late update, but I found my nitrated paradichlorobenzene product to be soluble in acetone and anhydrous isopropyl alcohol. All of the product was dissolved in about 30mL of 50/50 isopropyl alcohol-acetone mixture. 5 grams of sodium hydroxide was added, a large excess, and heated with strong stirring.

The solution's color changed from yellow (like the starting nitrated paradichlorobenzene) to a dark crimson red that was relatively opaque. After about 15 minutes, the solution was almost boiling. 20mL of water was added, and the solution was brought to a boil. Then, all of the remaining water and solids were transferred to a large beaker, more water was added, and everything water-soluble was discarded. The remaining solids were broken up, washed again, and then recrystallized by dissolving them in hot acetone and boiling it off.

This yielded a brown (dark crimson red in solution) solid that did not form large crystals. It was not hard and relatively easy to remove from the flat bottomed flask in which it was dissolved in acetone and recrystallized. It had a smell like paradichlorobenzene, but mustier.

This was all in an attempt to replace the chlorine next to the nitro group with a hydroxyl group.

I can post pictures of the product, weigh it, test its solubility, etc. if necessary. Was this sufficient to replace the chlorine with an OH group?
Thanks to Nicodem, AvBaeyer, Boffis, clearly_not_atara and SWIM for the suggestions.


[Edited on 1-3-2018 by Elemental Phosphorus]
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[*] posted on 2-3-2018 at 10:23


Well, the first problem I see is the presence of acetone as a solvent in the presence of sodium hydroxide which is likely to cause the acetone to turn into resinous crap if the reaction mention in my second point below does react with it first.

When some nitrohalobenzenes are heated with alcoholic hydroxide solutions they yield the appropriate halophenyl ether. Unfortunately many are reduced to azo or azoxybenzene compounds. There is a paper posted on SM that details these compounds and I believe it reducing agent too under these forcing conditions. As you can see from these comments there is a lot of scope for side reactions. The desired product 4-chloro-2-nitrophenol should be colourless when pure.

I would suggest trying this reaction with a strong potassium hydroxide solution. Although the nitrohalo compound isn't soluble in KOH the reaction product is. I am sure I have a reference to the preparation of 2-nitro-4-chloroaniline by fusing the nitrohalo compound with urea.

I'll see if I can find these references.
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[*] posted on 12-3-2018 at 14:52


Yes, there were a lot of problems with my process. Right now I only have fuming nitric acid, and while I could obviously dilute it, will it create a di-nitro product if I use it directly in mixed acid nitration?

Anders Hoveland posted a graph:

Here is a graph which shows that the paradichlorobenzene is mostly consumed after 15 minutes using 12M (molar concentration) HNO3, at only 10 °C.
http://www.chem.uiuc.edu/weborganic/arenes/Nitration/diClben...

Is it possible that at higher temperatures and using concentrated sulfuric acid as well that some of the di-nitro derivative may have been produced?
I will try again using the method you outline, but would you suggest using KOH in water, or alcohol (which alcohol, I have anhydrous methanol and isopropanol, but not ethanol) and if so, under reflux, or at room temp, etc. Naturally I would tend to think that reflux would be best, but I don't know.
(Polverone or woelen, can I have access to references?)



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[*] posted on 14-3-2018 at 05:39


Hi Elemental Phosphorus; I prepared a large amount of the mononitro compound using standard 68% nitric acid some years ago and now have rather a lot of it. I looked into dinitration and if you have fuming nitric acid this is possible, however, the the process yields a difficult to separate mixture of of 2,3; 2,5 and 2,6 dinitro compounds. There is a good deal of literature available on this nitration and the subsequent separation. If you are interested I can dig out and bundle up the papers but some have already been linked to above (Nicodem).

These papers also contain a fair amount of information about preparing the diamino derivatives too.
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[*] posted on 4-8-2018 at 12:37


Sulfonation of p-dichlorobenzene occurs in 10% oleum:

https://books.google.com/books?id=eopPAQAAMAAJ&pg=PA152&...

The resulting 2,5-dichlorobenzenesulfonic acid is very strong, comparable to perchloric acid, but much more stable.




[Edited on 04-20-1969 by clearly_not_atara]
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