Questions tagged [electrophilic-substitution]
use for reactions where an electrophile (electron-deficient species) displaces a substituent. Reactions like nitration fall under this category
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When does the isotope of hydrogen in benzene effect the rate of electrophilic aromatic substitution?
Replacing hydrogens in benzene by deuterium slows down halogenation and sulphonation but not nitration. I am not able to figure this out by their mechanisms. Why does this happen?
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Why doesn't aromatic substitution add at multiple positions in one reaction?
When you do aromatic substitutions, you usually see the major products with one substituent added. My question is why can't you add multiple substituents in one reaction? For example, the image below ...
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Aromatic Substitution in acidic medium
Find product A.
I tried solving but why isn't the answer this
The answer is given this
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What is the electrophile in Perkin's condensation reaction?
In Perkin's reaction, an aromatic aldehyde reacts with an acid anhydride to give an alpha-beta unsaturated aromatic acid. Which reactant is the electrophile and which one is the nucleophile?
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Hell-Volhard-Zelinski Reaction [closed]
What is the role of red phosphorus in hvz reaction?
Initially I think that red phosphurus is nothing but a catalyst. But it is not a catalyst.
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Electrophilic Aromatic substitution reactions of aromatic compounds [closed]
Benzene and substituted benzene (phenols, aromatic ethers, benzaldehyde, aromatic ketones like acetophenone, benzoic acid, aniline and nitrobenzene) generally can undergo electrophilic Aromatic ...
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What happens when FeF3 is reacted with benzene? [closed]
My text book says that halobenzenes can be prepared by aromatic substitution on benzene ring by using Fe or FeX3 as Lewis acid but this method isn't useful for preparation of fluoro benzene because of ...
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The main difference between using AlCl3 and FeCl3 in Friedel-Crafts alkylation
What is the main difference between using $\ce{AlCl3}$ and $\ce{FeCl3}$ in Friedel-Crafts alkylation?
Is that $\ce{FeCl3}$ disfavors carbocation rearrangement in Friedel-Crafts alkylation?
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Electrophilic Substitution with Ceric Ammonium Nitrate and Lithium Bromide as reagents
The 2020 IChO Preparatory Problem List (source here) had the following reaction as part of the solution to the first question:
(CAN = Ceric Ammonium Nitrate).
What is the mechanism for this '...
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Why don't phenol behave like aniline in electrophilic substitutions?
As far as I know, many electrophilic aromatic substitution reactions fail to undergo the usual way in aniline. This is due to $\ce{-H2N}$ group being basic (pKa of $\ce{NH3}$ = 38), even it is ...
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1answer
80 views
Acids used in Friedel-Crafts alkylation
I am learning adding alkyl groups to benzene using Fridel-Crafts alkylation:
I know that it is very common to use $\ce{AlCl3/AlBr3}$ as Lewis acid catalyst in this reaction. But I am just wondering ...
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734 views
activating and deactivating groups and directing effect
In electrophilic aromatic substitution:
I have just learnt a 'rule' about benzene with more than 1 substituents attached (excluding the effect on steric hindrance):
if a strong activating group (EDG) ...
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1answer
263 views
Electrophilic substitution on Borazole
As Borazole ($\ce{B3N3H6}$) is aromatic, it shows electrophilic aromatic substitution. Now, my question is when borazole undergoes electrophilic aromatic substitution reaction, on which atom does the ...
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1answer
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Regioselectivity in Electrophilic Aromatic Substitution of Pyrrole and Indole
If we look into the structures of Pyrrole and Indole, they are very similar. Only Indole has one extra Benzene ring attached to it, i.e. if we attach one Benzene ring to Pyrrole, what we'll have is ...
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1answer
115 views
Nitro-substitution [closed]
Here I expected (b) to happen via nucleophilic substitution, but contrary to that (a) is the one occuring. What exactly is happening here?
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Steric Effects in Friedel-Crafts Reactions
I recently came across a Friedel-Crafts reaction happening between benzoyl chloride and mesitylene with $\ce{AlCl3}$ as a catalyst. Apparently this reaction doesn't occur due to steric effects even ...
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227 views
Which is the major product of bromination of 3-(dimethylamino)benzamide, ortho or para?
I know that A will most probably not happen because of high steric hindrance. However between B and C, will B become the major product? Because $\ce{-N(CH3)2}$ is less bulky compared to $\ce{C=O-NH2}$,...
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When we cannot use Friedel-Crafts acylation to insert alkyl group?
Questions:
Show a probable synthethic pathway to obtain the first molecule, I.
Will the same strategy be used to insert the alkyl group for J. Explain.
My answers (please tell me if there is any ...
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Friedel-Crafts's alkylation of Toluene [duplicate]
In the Friedel-Craft's alkylation of Toluene with $\ce{CH3Cl}$ in the presence of $\ce{AlCl3}$, the major product was meta - substituted. My teacher gave it to me as an exception. Is there any ...
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Will ipso substitution work in both cases of vanillic and isovanillic acids here or not?
What will be the product of the 2 reactions when bromine is taken in excess?
I think ipso substitution will work here and there will be two $\ce{Br}$ substituting in both products, but in the book it ...
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1answer
51 views
Order of activating ability in electrophilic aromatic substitutions
From A Guidebook to mechanism in organic chemistry by P. Sykes [1, p. 155]:
The activating effect of $\ce{Y}$ on the nucleus is found to increase, i.e.
the overall rate of substitution increases, in ...
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1answer
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Does the first step in electrophilic aromatic substitution follow equilibrium? If so, can equilibrium constant be calculated?
Using chlorine (a Lewis base) and ferric chloride (a Lewis base) as an example, the first step I saw in the textbook looks like this:
The picture above depicts the Step 1 in the EAS mechanism using ...
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1answer
85 views
Electrophilic attack of X+ on double bond
Is it the double bond attacking the $\ce{X+}$ ion or the other way around?
Also, does it form a cyclic transition state if it isn't bromine or chlorine?
Eg. cyclohexene $+ \,\ce{Cl+ ->}$ cyclic ...
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1answer
220 views
What happens to the NMR of an alcohol when D2O is added?
What difference you expect in the 1H NMR spectrum of phenol in $\ce{CDCl3}$ after a drop of $\ce{D2O}$ is added to the test tube?
1) Since the $\ce{-OH}$ of the phenol is quite acidic, it undergoes ...
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2answers
136 views
Bromination on the aromatic ring vs aliphatic chain
I thought that the answer would be a simple electrophillic aromatic substitution and as the carbonyl is a meta director, the bromine would be present meta to the group.
But the given answer was the α-...
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418 views
Kolbe Schmitt followed by methylation
The first step in this synthesis is a Kolbe Schmitt process, but why is two equivalents of base needed? Also, what is the purpose of the two equivalents of methyl iodide? I assumed that there will be ...
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Meta product in the nitration of aniline [duplicate]
I recently read that nitration of aniline yields significant meta product. The text also mentions that in reaction mixture almost all of the aniline exists as anilinium ion.
However, the anilinium ...
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2answers
310 views
Why are Friedel Crafts reaction not possible for molecules less activated than benzene?
I know that Friedel Crafts alkylation reaction are not possible for aniline and phenol since they form complexes with Lewis Acids. But our teacher told us that Friedel Crafts reactions aren't possible ...
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1answer
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Major product of mononitration of 3-methylphenol
From NCERT Class Chemistry Part 2:
Example 11.5
Write the structures of the major products expected from the following reactions:
(a) Mononitration of 3-methylphenol
(b) Dinitration of 3-methylphenol
...
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1answer
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Reactivity in electrophillic substitution [closed]
When comparing maximum reactivity of a compound in electrophillic addition, what factors are kept in mind while comparing propene and trans-2-butene?
Why is trans-2-butene more reactive in this case ...
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How far does the delocalisation (resonance) effects for substituents extend for a conjugated system?
Let's say we have a conjugated system like this one:
Now, the delocalisation of the benzene electrons with the nitrate system means that the ortho, and para positions on the immediate benzene ring ...
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1answer
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Reimer-Tiemann reaction on indole
According to me net reaction should be at $\ce{C3}$ when Reimer-Tiemann reaction is done on indole (see image), since in the resonance structure, negative charge is on this carbon.
But, the answer ...
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1answer
179 views
Validity of the leveling effect of water in nitration reactions
Wikipedia gives this as the levelling effect of water
Any acid that is stronger than $\ce{H3O+}$ reacts with $\ce{H2O}$ to form $\ce{H3O+}$. Therefore, no acid stronger than $\ce{H3O+}$ exists in $\...
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Directing effect in Intramolecular Friedel Crafts Alkylation
This reaction should cause ring closure at either the $o-$ or $p-$ position relative to the methyl substituent on the ring (as methyl is an $o,p-$directing group), giving the following products:
The ...
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Explanation of the third ortho effect
The third ortho effect is, according to Wikipedia, the phenomenon where in a ring with a meta and an ortho-para director both meta to each other has the incoming nucleophile go ortho to the meta ...
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1answer
387 views
How does a halogen react in an electrophilic substitution reaction
From what I understand, electrophiles are electron deficient and therefore would be attracted to the electron-rich benzene ring. So would the correct answer be A?
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1answer
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Solvent Effects in Friedel–Crafts Reaction
While reading about the factors affecting the product of Friedel–Crafts acylation with acetyl chloride, I came across a reaction involving napthalene in two different solvents: in nitrobenzene ...
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1answer
371 views
Is m-cresol or p-cresol more reactive towards electrophilic substitution?
Which is more reactive towards electrophilic substitution, meta-cresol or para-cresol?
Both oxygen and methyl are activating groups. I don't know on what basis do I compare their reactivity. There's ...
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979 views
Electrophilic substitution of benzene with conc. HNO₃ and HNO₂
The following question was given in my FIITJEE study material:
$$\ce{Benzene + \text{conc.} HNO_3 + HNO_2 ->}$$ Final product of the reaction is:
,
,
,
I started with the solution by deciding ...
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1answer
204 views
Effect of chloromethyl substituent vs methyl substituent on yields of nitration
The effects of $\ce {-CH3}$ and $\ce {-CCl3}$ substituents on the product distribution of an electrophilic aromatic substitution reaction are unambiguous. The $\ce {-CH3}$ group exhibits a clear ...
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1answer
456 views
Lactone acylation
Can anyone propose/draw a mechanism for Method A, below, from this paper? Almost all other literature use method B and reagents such as SOCl2.
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Can anyone please help me how do you determine kinetically the fastest product of sulphonation of $\beta$ napthol?
I was asked a question in a paper where I was asked to identify the kinetically fastest product of sulphonation of $\beta$ naphthol.
Can anyone please help me how do you determine kinetically the ...
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1answer
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Why is formyl chloride unstable while higher acyl chlorides are stable?
Source: Paula Bruice Ed. 2017 Pg.877
From this excerpt, we infer that formyl chloride is unstable.
But how does that affect the reaction in any way? Is it just mentioned as a point to note or does it ...
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1answer
497 views
When does ipso attack occur in electrophilic aromatic substitution?
My textbook doesn't mention the conditions required for an ipso attack to occur. It just describes some examples where groups like $\ce{-C(CH3)}$ and $\ce{-SO3H}$ are replaced by $\ce{Br}$ using ...
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Nitrobenzene - Aromatic Substitution Reactions
Which EAS (electrophilic aromatic substitution) reactions does nitrobenzene show?
We know that nitrobenzene is particularly deactivated towards most such reactions, as the nitro group is strongly ...
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Find the increasing order of formation of ortho product
Find the increasing order of ortho product formation when Y is (i) F, (ii) Cl, (iii) Br, (iv) I.
We know that halides are ortho, para directing for EAS reactions and we consider the electronic ...
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Distinguishing between a nucleophilic substitution and an electrophilic substitution
Why don't we consider all nucleophilic substitution reactions as electrophilic reactions and vice versa?
For example, look at this reaction I found in my textbook. (See picture)
This is an ...
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Isoptope effect on electrophilic aromatic substitution
My book reads
Sulphonation will be the most effected electrophilic aromatic substitution reaction when benzene is replaced by hexadeutrobenzene.
I am not able to figure out how. All EAS reactions ...
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598 views
Kinetic and thermodynamic control of sulphonation of toluene
Sulfonation of toluene with conc. $\ce{H2SO4}$ at room temperature gives ortho- and para-toluenesulphonic acid (with $95 \%$ yield), whereas sulfonation of toluene with conc. $\ce{H2SO4}$ at $\pu{150-...
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1answer
451 views
Reaction between phenylamine and halogens
I understand that phenylamine is considerably more reactive than benzene, meaning that it is able to react with bromine water to give 2,3,6-tribromophenylamine. But I was then wondering why I haven't ...
