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p-hydroxybenzonitrile synthesis
Hello everybody,
I m trying to synthesize p-hydroxybenzonitrile using following route-->p-hydroxybenzoic acid--> Methyl paraben
-->p-hydroxybenzamide-->p-cyanophenol. I have succesfully synthesized o-hydroxybenzonitrile using the same route but the process doesn't works
for p- cyanophenol.The reaction proceeds after purging ammonia to methyl paraben but the formed amide gets converted to paraben after some time. Dont
suggest me Oxime route & Urea route;coz i have used those succesfully 
Just wanna know whats exactly wrong when p-hydroxybenzoic acid is used instead of salicylic acid for methyl paraben route  ...Any Idea Guys??
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fledarmus
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I'm not sure exactly what you're saying - does the methyl paraben form the amide but the reaction spontaneously reverses to reform the ester when you
remove the ammonia atmosphere? In that case, how are you detecting product formation? If you are actually forming the amide, and you suspect that the
methanol which is formed is driving the reaction back to the ester when you purge the ammonia, you might be able to add 4A or 5A molecular sieves to
remove the MeOH as it is formed.
Or is the reaction just giving you none of your expected amide product? If that is the case, what are your conditions for going from the ester to the
amide? My guess would be that either you are forming an ammonium phenoxide salt which in the ortho case positions the ammonium right next to your
ester for the addition reaction, but in the para case keeps it on the opposite side of the ring; or that hydrogen bonding between the ortho hydroxy
and the ester stabilize the ammonia addition while the para hydroxy is unable to do that.
In the first case, it is possible that increasing the concentration of your methyl paraben would allow intermolecular reaction, where you don't need
such high concentrations in the ortho case because it is an intramolecular reaction. In the second case, you may have to prepare a more active ester
to get the ammonia to react.
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Resonance frequency
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Thanks a lot friend!!
I think you are ryt , i was trying to monitor formation of amide by TLC where presence of spot other than methyl paraben was assumed to be amide coz i
wasnt having external standard for amide. I was quite prejudice about the reaction mechanism coz i was trying to attack lone pair of Nitrogen from
ammonia gas on carbonyl carbon from methyl paraben to form a gem diol which on dehydration supposed to give amide. But formation of ammonium phenoxide
seems to be a promising explanation to describe abnormal behaviour of the methayl paraben route. Thanks once again.
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hemrajpatil
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I want to make 4 hydroxy benzonitrile by using para hydroxy benzoic acid ,urea and sulphamic acid any idea about this route?
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forgottenpassword
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Quote: Originally posted by hemrajpatil  | | I want to make 4 hydroxy benzonitrile by using para hydroxy benzoic acid ,urea and sulphamic acid any idea about this route? |
What do you mean? Do you need the experimental procedure? I recall seeing something similar. It seems reasonable enough to try it,
at least.
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hemrajpatil
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Procedure for manufacturing of para cyano phenol by using Para hydroxy benzoic acid as a raw material
Hi Everybody,
I want to make 4 hydroxy benzonitrile by using para hydroxy benzoic acid ,urea and sulphamic acid any idea about this route?
Tell us laboratory experimental procedure
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forgottenpassword
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You're the one who keeps mentioning this procedure. You must know SOMETHING about it. What sources do you have already? I wouldn't want to replicate
what you already have! It would waste both of our time. If you could list the papers that you have, I shall look to see if there are any others that
discuss the same reaction. You posted your first question over a week ago. You could have tried the reaction and TOLD US whether it works, by now.
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CuReUS
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what about this route
nitrobenzene to Phenyl hydroxyl amine using Zn/aq NH4Cl
http://www.orgsyn.org/demo.aspx?prep=cv1p0445
rearragement of Phenyl hydroxyl amine to para amino phenol by bamberger rearrangement
http://en.wikipedia.org/wiki/Bamberger_rearrangement
treat para amino phenol with NaNO2 +HCl, followed by CuCN to get para hydroxy benzonitrile
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Nicodem
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And where do you have the reference to this unusual transformation?
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Metacelsus
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Nicodem, isn't that just a Sandmeyer reaction with cyanide as the nucleophile? Why is it "unusual"?
Anyway, here's a reference: http://www.orgsyn.org/demo.aspx?prep=cv1p0514
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Nicodem
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Because the nitrosation of p-hydroxyaniline gives the quinone diazide product. But never mind, meanwhile I actually checked the literature
and the quinone diazide formation is reversible so that p- and o-hydroxyanilines can be used in the Sandmeyer reactions.
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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CuReUS
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instead of using CuCN ,one can also use copper powder in the presence of excess aqueous KCN
see page 89 https://books.google.co.in/books?id=35xwBwjhe2MC&pg=PA87...
acoording to the orsyn page, nickel cyanide ( NiCN2 ) gives better yield than CuCN
also in the mechanism for sandmeyer reaction ,Cu first acts as reducing and then as oxidizing agent
so instead of CuCN ,can I2 and excess KCN be used
although the active species for the formation of the nitrile is K3Cu(CN)4
since para amino phenol oxidizes rapidly to benzoquinone imine
http://pubs.rsc.org/en/Content/ArticleLanding/1979/P2/P29790...
the diazotization reaction has to be done very quickly,and in the presence of highly acidic conditions,to minimize the oxidation of para amino phenol
also in the wiki sandmeyer page
http://en.wikipedia.org/wiki/Sandmeyer_reaction#Variations
there is a reaction involving an alkyl nitrite with an aromatic amine in the presence of a halogenated solvent ,which reaction is that ?
Nicodem -really clever of you to think about that possibility,i envy your knowledge and your brain 
could you please tell more about the quinone dizide reversal ?
how would the quinone structure look for o-hydroxy aniline?
also ,would the diazotization reaction take place faster or give better yields as there is an electron donating OH group para to the NH2
in the ring ?
it would be really helpful if you could post a link to the literature you referred (about the quinone diazide)
[Edited on 10-12-2014 by CuReUS]
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CuReUS
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| Quote: Originally posted by CuReUS |
nitrobenzene to Phenyl hydroxyl amine using Zn/aq NH4Cl
rearragement of Phenyl hydroxyl amine to para amino phenol by bamberger rearrangement
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no need to make the phenyl hydroxylamine from nitrobenzene
nitrobenzene can directly be converted to para aminophenol
http://www.sciencemadness.org/talk/viewthread.php?tid=27849#...
[Edited on 7-1-2015 by CuReUS]
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Yugen
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| Quote: Originally posted by hemrajpatil | Hi Everybody,
I want to make 4 hydroxy benzonitrile by using para hydroxy benzoic acid ,urea and sulphamic acid any idea about this route?
Tell us laboratory experimental procedure
|
Likely the simplest way to do this reaction is through electrosynthesis. First reduce the acid at a lead cathode. Next reflux Benzyl alcohol with HCl and Zinc chloride to get its Benzoyl chloride. Nucleophilic substitution with a large excess of ammonia in a basic ethanol solution will get you the 4-hydroxybenzylamine (if you don't use enough ammonia you will get secondary and tertiary amines, bad for this synth). Finally oxidize the benzylamine at a
nickel hydroxide anode to get your product. I haven't tried this, but it seems straight forward enough. Here's the reference for that nickel
oxidation.
Attachment: Oxidation of primary amines to nitriles at the nickel hydroxide electrode.pdf (108kB)
This file has been downloaded 477 times
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Loptr
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| Quote: Originally posted by Yugen | | Quote: Originally posted by hemrajpatil | Hi Everybody,
I want to make 4 hydroxy benzonitrile by using para hydroxy benzoic acid ,urea and sulphamic acid any idea about this route?
Tell us laboratory experimental procedure
|
Likely the simplest way to do this reaction is through electrosynthesis. First reduce the acid at a lead cathode. Next reflux Benzyl alcohol with HCl and Zinc chloride to get its Benzoyl chloride. Nucleophilic substitution with a large excess of ammonia in a basic ethanol solution will get you the 4-hydroxybenzylamine (if you don't use enough ammonia you will get secondary and tertiary amines, bad for this synth). Finally oxidize the benzylamine at a
nickel hydroxide anode to get your product. I haven't tried this, but it seems straight forward enough. Here's the reference for that nickel
oxidation.
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Where do you get nickel hydroxide electrodes?
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Yugen
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Nickel hydroxide electrodes
You get nickel hydroxide electrodes from a nickel nitrate solution, a plain nickel electrode anode, and an inert cathode of some other material type.
Probably a graphite cathode would work. Running a current through the solution will reduce the nickel nitrate to nickel hydroxide and nitric acid. As
this happens the nickel hydroxide will cover the graphite cathode in a thin film of NiOH, forming the desired electrode for the nitrile synthesis.
Also the reaction likely benefits from the nitric acid entering the solution because the acid will react with the nickel anode to generate more nickel
nitrate. Since electrosynthesis works on the surface of the electrode you don't need a thick layer on the graphite. You will have to experiment to see
how much NiOH you will need to deposit, but it is safe to say that you won't need a thick NiOH cake for the reaction to work.
Source:
From the Handbook of Inorganic Chemicals by Pradyot Patnaik (page 618)
| Quote: |
Nickel hydroxide in high purity is prepared by an electrolytic process using metallic nickel as the anode and nickel nitrate solution as the
electrolyte. Nickel hydroxide is electrodeposited at an inert cathode.
Nickel nitrate may be prepared by several methods based on the reaction of dilute nitric acid on nickel powder, nickel oxide or nickel carbonate. The
reaction is exothermic and requires controlled cooling during production. |
Enjoy
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CuReUS
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don't you mean benzyl chloride ? are you sure ZnCl2 will be necessary? since the benzylic carbocation is stabilized by resonance,the
substitution should take place easily.
| Quote: | | Nucleophilic substitution with a large excess of ammonia in a basic ethanol solution will get you the 4-hydroxybenzylamine(if you don't use enough
ammonia you will get secondary and tertiary amines, bad for this synth) |
you could also do the delepine reaction to get only primary amine
http://en.wikipedia.org/wiki/Del%C3%A9pine_reaction
for making p-hydroxybenzonitrile from p-hydroxybenzoic acid
you could either convert the COOH to COCl ,treat it with NH3 and then dehydrate the amide using P2O5 to get nitrile
or you could esterify the COOH,treat it with DIBAL to get CHO and then react it with HN3 to get the p-hydroxybenzonitrile
http://en.wikipedia.org/wiki/Diisobutylaluminium_hydride#Use...
http://en.wikipedia.org/wiki/Schmidt_reaction
[Edited on 10-1-2015 by CuReUS]
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Yugen
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| Quote: Originally posted by CuReUS |
don't you mean benzyl chloride ? are you sure ZnCl2 will be necessary? since the benzylic carbocation is stabilized by resonance,the
substitution should take place easily.
| Quote: | | Nucleophilic substitution with a large excess of ammonia in a basic ethanol solution will get you the 4-hydroxybenzylamine(if you don't use enough
ammonia you will get secondary and tertiary amines, bad for this synth) |
you could also do the delepine reaction to get only primary amine
http://en.wikipedia.org/wiki/Del%C3%A9pine_reaction
for making p-hydroxybenzonitrile from p-hydroxybenzoic acid
you could either convert the COOH to COCl ,treat it with NH3 and then dehydrate the amide using P2O5 to get nitrile
or you could esterify the COOH,treat it with DIBAL to get CHO and then react it with HN3 to get the p-hydroxybenzonitrile
http://en.wikipedia.org/wiki/Diisobutylaluminium_hydride#Use...
http://en.wikipedia.org/wiki/Schmidt_reaction
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Ah you are right, Benzoyl chloride should be corrected to be Benzyl chloride... damned old school names, I always add a vowel that shouldn't be in
there IPAC names are better but nobody uses them for some reason...
Anyways, benzyl chloride probably can be made easily from benzyl alcohol without Zinc chloride, but why not strive for higher yields? Even textbooks
recommend more vigorous conditions in their protocols for benzyl chloride prep. For instance Vogel's 5th edition calls for the powerful chlorination
agent SO2Cl2... even when they go to that extreme they only get a 79% yield. If adding a little zinc dust to the reflux boosts
one's yield even a couple percentage points it still seems like a win to me. It's not exactly like zinc is rare or anything, scratch a U.S. penny and
you'll see what I mean.
And yes, you could get your desired product through a number of ways (which is why O-chem interests me). For instance the Wikipedia page for toluene describes an easier way to benzyl chloride than using electrosynthesis from benzoic acid. I just find electrosynthesis to be interesting
so it jumps to mind first.
As for the amine reaction, I agree, amine alkylation is a terrible idea. I admit that totally. It just doesn't take a whole lot of forethought to do
things that way. That is you can walk into most home labs and do an experiment without calling on Sigma Aldrich and the like. Buying
hexamethylenetetramine for a Delépine reaction or buying phthalimide for a Gabriel synthesis is just too much work in a totally different way (the
problem of stocking a lab). Plus buying reagents which have no other use than to form amines is bound to attract unwanted attention from NSA and DEA
authority types. Even if you aren't doing anything bad, nobody enjoys that kind of harassment and invasion of privacy.
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Loptr
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| Quote: Originally posted by Yugen | You get nickel hydroxide electrodes from a nickel nitrate solution, a plain nickel electrode anode, and an inert cathode of some other material type.
Probably a graphite cathode would work. Running a current through the solution will reduce the nickel nitrate to nickel hydroxide and nitric acid. As
this happens the nickel hydroxide will cover the graphite cathode in a thin film of NiOH, forming the desired electrode for the nitrile synthesis.
Also the reaction likely benefits from the nitric acid entering the solution because the acid will react with the nickel anode to generate more nickel
nitrate. Since electrosynthesis works on the surface of the electrode you don't need a thick layer on the graphite. You will have to experiment to see
how much NiOH you will need to deposit, but it is safe to say that you won't need a thick NiOH cake for the reaction to work.
Source:
From the Handbook of Inorganic Chemicals by Pradyot Patnaik (page 618)
| Quote: |
Nickel hydroxide in high purity is prepared by an electrolytic process using metallic nickel as the anode and nickel nitrate solution as the
electrolyte. Nickel hydroxide is electrodeposited at an inert cathode.
Nickel nitrate may be prepared by several methods based on the reaction of dilute nitric acid on nickel powder, nickel oxide or nickel carbonate. The
reaction is exothermic and requires controlled cooling during production. |
Enjoy |
Interesting. I never really got into electrochemistry in college, and didn't use my head before asking that question!
Electroplating, of course!
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AvBaeyer
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I wish to comment on Yugen's statements about the preparation of benzyl chloride from benzyl alcohol. There is no need for zinc chloride or any exotic
chlorinating agents or reaction conditions. Benzyl alcohol reacts cleanly with concentrated hydrochloric acid (12M) to give the chloride in very good
yields after distillation [Ref: JF Norris, American Chemical Journal 1907, v38, 647-642]. I have run this reaction several times on several different
scales. An example preparation I have done follows (do with with gloves and good ventilation!):
60 ml of 12M hydrochloric acid is added to 20.0 g benzyl alcohol whereupon one obtains a clear solution. The reaction mixture is slowly heated to 60C
(oil bath) during which it becomes cloudy and an oil begins to separate. After about 20 minutes at 60C the reaction, which is now biphasic, is removed
from the heating bath and cooled to ambient. The mixture is transferred to a separatory funnel (use caution) and the upper layer (benzyl chloride)
isolated. The aqueous layer is extracted 1x25 ml hexanes and the extract is conbined with the crude benzyl chloride. The combined organic layers are
washed 2x25ml water, 1x25ml 5% sodium bicarbonate and 2x25 ml brine then dried over calcium chloride. Removal of the hexanes by distillation affords
21.7 g (92%) of a colorless product. Distillation affords 19.4 g (83%, bp 51-52 C @ 5 mm) pure benzyl chloride. A small pot residue remains.
Note: This reaction also works with hardware store muriatic acid (ca 10M) but is not so clean as the benzyl alcohol is not completely soluble.
However, addition of 1 ml 12M HCL for each 10ml of 10M HCl gives a reasonable result similar to the above procedure. It just takes a bit longer.
Although I have not yet tried, I assume that the used 12M HCl could be recycled after "fortifcation" with a small amount of fresh 12M HCl.
Hope this is of interest,
AvB
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CuReUS
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| Quote: Originally posted by Yugen | | Buying hexamethylenetetramine for a Delépine reaction or buying phthalimide for a Gabriel synthesis is just too much work in a totally different way
|
I am sure our energetic forum friends will agree that making Hexamine is easier than making instant coffee
https://www.youtube.com/watch?v=d2N0zAoVYew
IIRC,chemosynthesis was talking about an OTC source for phthalimide,
http://www.sciencemadness.org/talk/viewthread.php?tid=45844#...
but personally I don't prefer the gabriel synthesis because hydrolysing the intermediate can be quite difficult
| Quote: | | Even textbooks recommend more vigorous conditions in their protocols for benzyl chloride prep. For instance Vogel's 5th edition calls for the powerful
chlorination agent SO2Cl2... even when they go to that extreme they only get a 79% yield. |
is it SO2Cl2 or SOCl2 ?
| Quote: | | For instance the Wikipedia page for toluene describes an easier way to benzyl chloride than using electrosynthesis from benzoic acid.
|
if you are talking about using HCl/H2O2 for making benzyl chloride,I dont think that will work.
http://chemwiki.ucdavis.edu/Organic_Chemistry/Hydrocarbons/A...
using TCCA or passing Cl2 in boiling toluene is the answer
| Quote: | | Anyways, benzyl chloride probably can be made easily from benzyl alcohol without Zinc chloride, but why not strive for higher yields? .... If adding a
little zinc dust to the reflux boosts one's yield even a couple percentage points it still seems like a win to me... |
in chemistry,less is more 
[Edited on 14-1-2015 by CuReUS]
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CuReUS
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| Quote: Originally posted by hemrajpatil | | I want to make 4 hydroxy benzonitrile by using para hydroxy benzoic acid ,urea and sulphamic acid any idea about this route? |
This thread might help you
http://www.sciencemadness.org/talk/viewthread.php?tid=38017
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riyaaz98
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i need some more information on
treat para amino phenol with NaNO2 +HCl, followed by CuCN to get para hydroxy benzonitrile
any articles of patents??
thanks for the help !!
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DraconicAcid
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Hmmm....This seems like an accessible way to convert an acid into an aldehyde without expensive borohydrides or LiH4.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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