Questions tagged [phenols]

Use this tag for questions about phenols, their synthesis, analysis, properties and more. Do not use the 'alcohols' tag for phenols due to the differences between the two classes.

Filter by
Sorted by
Tagged with
23
votes
4answers
31k views

Why is acetic acid more acidic than phenol?

Acetic acid (ethanoic acid, $\mathrm pK_\mathrm a \approx 5$) is more acidic than phenol ($\mathrm pK_\mathrm a \approx 10$), which is reflected in their reactivity with a weak base such as sodium ...
13
votes
3answers
32k views

Friedel–Crafts reaction of phenol

Does phenol undergo Friedel–Crafts reactions or does it react with Lewis acids like aniline does?
13
votes
1answer
49k views

What is the product of the chemical reaction between phenol and ferric chloride?

The chemical reaction between phenol and ferric chloride is a test for the presence of phenol. They react with each other to produce a violet complex. However, the reaction is given differently in ...
32
votes
1answer
51k views

Acidity of substituted phenols

Phenol has a $\mathrm pK_\mathrm a$ approximately equal to $9.9$. When one studies the acidity of chlorophenols, one notices the following: First of all, chlorophenols are more acidic than phenol, ...
18
votes
4answers
28k views

Acidity order of nitrophenols

As in other posts I have seen and learnt that, if one is given four compounds, namely para-nitrophenol, ortho-nitrophenol, meta-nitrophenol and phenol and is told to arrange them in order of acidity, ...
24
votes
2answers
4k views

Electrophilic Aromatic Substitution: Are protonated OH-groups ortho-/para- or meta-directing?

In Electrophilic Aromatic Substitution ($\text{S}_{\text{E}}\text{Ar}$) reactions groups that can donate an electron pair into the aromatic ring, e.g. $\ce{-OH}$ or $\ce{-NH2}$, are ortho-/para-...
13
votes
3answers
18k views

Why is a hydroxyl group more activating than a methoxy group in electrophilic aromatic substitution?

Why is phenol more reactive towards electrophilic substitution than methoxybenzene? Isn't the lone pair on the methoxy group oxygen more available for participating in resonance into the ring than the ...
9
votes
2answers
10k views

Inductive vs resonance effects and the acidity of phenol

A lot of people rationalize the acidity of phenol by saying that resonance is responsible for much of phenol's acidity as opposed to aliphatic alcohols. However, this image suggests that in fact the ...
40
votes
1answer
87k views

Differences between phenols and alcohols

I know phenols are more acidic as compared to alcohols, but are they considered different from alcohols? Sure, you can study something as a subset, but are phenols considered a subset of alcohols, or ...
10
votes
1answer
6k views

Why is picric acid more acidic than carbonic acid?

I just had a question in a test asking to compare the relative acidity of picric acid (TNP) and carbonic acid, $\ce{H2CO3}$ (not phenol). It turns out that TNP is more acidic. I have no idea why? Is ...
23
votes
4answers
66k views

Reason for the stronger acidic property of phenol than alcohol

In phenol, pulling the $\mathrm{p}_z$ electrons from the oxygen atom into the ring causes the hydrogen atom to be more partially positive than it is in aliphatic alcohols. This means it is much more ...
7
votes
1answer
2k views

Synthesis of 2-methyl-4-nitrophenol from benzene?

Benzene first reacts with the reagents $\ce{CH3Cl/AlCl3}$, to attach a methyl ($\ce{CH3}$) group to the benzene ring. Then I suggested reacting with $\ce{OH-}$. Because the methyl group is an ...
7
votes
1answer
12k views

Reaction of phenol and zinc dust

There is a reduction reaction of phenol with zinc dust which is found in many books. $\ce{Ph-OH + Zn -> Benzene + ZnO}$ However, a simple google search fails to explain anything about the ...
6
votes
1answer
2k views

Can the hydroxyl group of 4-hydroxybenzoic acid react with phosphorus pentachloride?

I learned that, a phenol will not react (or react very slowly) with $\ce{PCl5}$ due to its stabilized structure. How about the $\ce{-OH}$ group on the benzene ring of 4-hydroxybenzoic acid? Will that ...
6
votes
2answers
4k views

How do we know whether we will get a mono substituted or tri-substituted product during electrophilic aromatic substitution?

For example consider the bromination of phenol we get the tri-substituted product (even though bromine is deactivating so I suppose it should deactivate the ring with each addition) while sulphonation ...
1
vote
1answer
1k views

Reactions of phloroglucinol

Does phloroglucinol respond to the iodoform test? cerric ammonium nitrate test? 2,4-DNP test? I couldn't find any good sources that answer any of these. I thought of this: Tautomerism can "change" ...
0
votes
2answers
434 views

Organic problem: acidity of benzene substituents

Ortho nitro benzoic acid is more acidic than para benzoic acid since intermolecular H bonding comes into play in the latter compound. But why is that among para nitro phenol and ortho nitro phenol, ...
13
votes
3answers
47k views

Gattermann-Koch Reaction with Phenol Substrates

The Gattermann-Koch Reaction involves the formation of an aryl aldehyde using carbon monoxide and hydrochloric acid as reactants. The reaction is catalyzed by aluminium trichloride in the presence of ...
2
votes
3answers
35k views

Why is meta-nitrophenol less acidic than para-nitrophenol? [closed]

My professor said while explaining the acidic nature of phenol that meta-nitrophenol is less acidic than para-nitrophenol, and gave the reason that resonance doesn't play on meta, but I didn't get it.
9
votes
2answers
11k views

Can phenol be detected with a ceric ammonium nitrate test?

Today, I came across a question which asked name three reagents can be used for identification of phenol. The answer given was: Neutral $\ce{FeCl3}$ $\ce{ NaNO2 +HCl}$ $\ce {(NH4)2[Ce(NO3)...
8
votes
1answer
132 views

Why is quinone mono oxime more stable than 4-nitrosophenol?

When we do nitrosation of phenols, we get para-nitrosophenol as the major product, which tautomerises to quinone mono oxime. This article states that it largely exists in the quinonoid form. My ...
6
votes
1answer
2k views

Nomenclature of benzene derivatives with two functional groups

In several places, I have seen that while naming benzene derivatives, no priority for substituents is followed. For example, I've seen both 2-hydroxyaniline and 2-aminophenol being used. Is there an ...
6
votes
0answers
2k views

Why is o-fluorophenol a stronger acid than p-fluorophenol?

The $\mathrm{p}K_\mathrm{a}$ value of o-fluorophenol is $8.7$, while that of the p-fluorophenol is $9.9$. It's obvious that the inductive effect is more dominant at ortho-position, which results in a ...
4
votes
0answers
559 views

Diazo Coupling reaction with para-substituted phenol?

Usually Diazo coupling occurs at para-position unless the para-position is occupied, in which case coupling occurs at ortho-position. While solving questions I found in both the cases as shown, the ...
1
vote
1answer
1k views

Physical properties of phenols

Order of increasing boiling point is p-nitrophenol > m-nitrophenol > o-nitrophenol. The difference between bp of p- and o-nitrophenol is that one form intermolecular hydrogen bonding while other form ...
0
votes
3answers
670 views

Is there an intramolecular hydrogen bond in guaiacol?

Is there a hydrogen bond between the $\ce{H}$ atom of $\ce{-OH}$ group and the $\ce{O}$ atom of the $\ce{-OCH3}$ group in ortho-methoxyphenol? I was told no. But I want to know why.
0
votes
1answer
8k views

Which Phenols give the colours blue, green or violet in the neutral FeCl3 test?

I have read about the neutral FeCl3 test for Phenols, where a positive test is indicated by the colour of the solution which ranges from green to blue to violet. But which specific derivatives of ...