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.

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40
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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 ...
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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, ...
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2answers
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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-...
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4answers
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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 ...
23
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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 ...
18
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5answers
9k views

Strength of hydrogen bonding in phenol or methanol

I wanted to know whether hydrogen bonding is stronger in phenol or methanol. I saw on Wikipedia about the enthalpies of hydrogen bonding in various cases. but could not find the answer to this ...
18
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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, ...
13
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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
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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 ...
13
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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 ...
13
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3answers
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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 ...
12
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3answers
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How can we synthesize para-nitrophenol

During nitration of phenol, both para- and ortho-nitrophenols will be formed. Is there any way in which we can synthesize para-nitrophenol only?
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2answers
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Why isn't 4-hydroxybenzoic acid formed along with salicylic acid in Kolbe's reaction?

I've read that in Kolbe's reaction of phenol, i.e. reaction of phenol $(\ce {C6H5OH})$ with $\ce{NaOH}$ forming sodium phenoxide $(\ce {C6H5O^{-}Na^{+}})$, followed by reaction with $\ce{CO_2}$ and ...
11
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2answers
791 views

Alkylation of 1-naphthol in trifluoroethanol versus in DMSO

I am supposed to work out which product is formed in which solvent when naphthalen-1-olate is treated with benzyl iodide. DMSO is a polar aprotic solvent, as it does not possess an acidic hydrogen. ...
10
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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 ...
9
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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)...
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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 ...
9
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1answer
143 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 ...
9
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1answer
3k views

Reaction between phenol and nitrous acid

My question is about the products formed when phenol reacts with nitrous acid. I googled it and reached this PubChem paper (DOI: 10.1016/S0045-6535(02)00857-3), which states: It was found that ...
8
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3answers
951 views

Reaction mechanism of rearrangement

I am currently studying for my organic chemistry exam, but there is one problem I do not understand. Unfortunately, I do not have any solutions. See image for the problem. My first thought was the ...
8
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2answers
3k views

Aromatic ether to phenol reagents

I have been asked to identify suitable reagents for the following transformation: (Apologies it's back to front - the question is a map of reactions and I took a snapshot). I really have no idea ...
8
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2answers
6k views

Reimer–Tiemann-like reaction of catechol with diiodomethane

I have studied the Reimer–Tiemann reaction of phenol with chloroform in presence of aqueous strong alkali. It takes place with intermediate dichlorocarbene. I have also studied the Reimer–Tiemann "...
8
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1answer
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Phenol smell from hands

It is a question which I faced when I was in Senior year in high school, I used my hands to handle phenol which has turned pink due to oxidation, I washed my hands with all kind of soaps but smell in ...
8
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1answer
1k views

What is the mechanism of oxidation of phenol to benzoquinone?

I looked up the mechanism in a lot of organic chemistry books, including Clayden, Klein, Solomons, McMurry but I couldn't find the mechanism of oxidation of a phenol. I also looked it up in ...
7
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1answer
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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 ...
7
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1answer
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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
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1answer
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Selective alkylation of carboxylic acid versus phenol

Starting from the ketone shown, I plan to use a haloform reaction to transform the acetyl group into a carboxylic acid. Following that, there are two alkylations to be carried out: one esterification ...
7
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1answer
5k views

How does the solvent determine whether mono- or tribromination of phenol occurs?

In phenol, the $-\ce{OH}$ group activates the benzene ring towards electrophilic substitution. But why is it that the electrophilic bromination of phenol gives trisubstitution (forming 2,4,6-...
7
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1answer
2k views

Evaluation of a synthesis from aspirin to paracetamol from this Nile Red video

Recently the YouTube chemist Nile Red performed an interesting conversion from aspirin to paracetamol Aspirin to Acetaminophen - Part 1 of 6: Extracting Aspirin from Pills using the following steps: ...
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Mechanism of Hypervalent Iodine Phenolic Coupling

I need some help understanding the hypervalent iodine phenolic coupling reaction taking place in this synthesis of morphine, the reaction uses $\ce{PhI(OAc)2}$ as the hypervalent reagent and ...
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3answers
7k views

How are phenols made?

What is the equation and conditions for the synthesis of phenols? Would it work if we added $\ce{NaOH}$ to benzene and then refluxed?
6
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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
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1answer
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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
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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 ...
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0answers
616 views

Why does phenol react on oxygen in the Gattermann–Koch reaction?

When discussing the Gattermann–Koch reaction on phenol substrates, it has been said that O-acylation is a problematic competing reaction as in a phenol, there's high electron density on the O atom [...
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0answers
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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 ...
5
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2answers
1k views

Suggestion for a Synthesis of Paracetamol — plausible?

I have seen a number of different plausible syntheses for paracetamol but they suffer from problems such poor regioselectivity of aromatic substitution (usually when nitrating phenol getting a mixture ...
5
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3answers
5k views

Why does the -OH group in β-naphthol direct the incoming diazonium salt towards the ortho position? [duplicate]

In the following reactions, the major product W is I was doing this question which asks me the product of a diazotisation coupling reaction between diazonium chloride and β-naphthol. I know that the ...
5
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1answer
297 views

Partial oxidation of toluene

While reading the preparation of phenol from cumene by reaction with $\ce{H2O2}$ or partial oxidation, I was curious to find out why toluene wasn't used. I checked the literature and found that ...
5
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1answer
156 views

pKa of phenols using UV-Vis spectroscopy

I have done an experiment where I dissolved four different substituted phenols in acidic, basic, and buffer solutions, and recorded the UV-Vis spectra for each. I'm supposed to pick a wavelength where ...
5
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1answer
2k views

Reaction of chloroform, resorcinol and strong base

A common reaction used to identify resorcinol (benzene-1,3-diol) in the laboratory is to react it with chloroform in presence of 30% sodium hydroxide (NaOH). A red coloured solution (or precipitate) ...
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2answers
880 views

How to esterify phenol with oxalic acid?

Is it possible to fully esterify phenol with oxalic acid in order to get diphenyl oxalate? What catalyst should I use and is the synthesis possible to perform at home with hobby equipment?
5
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2answers
860 views

Phenol and Deuterated Sulphuric Acid

What happens when phenol reacts with $\ce{D2SO4}$ in presence of $\ce{D2O}$? How many hydrogens in total are replaced by deuterium? Is the hydrogen of the hydroxyl group and three hydrogens ortho ...
5
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3answers
2k views

Why is the para product major in the nitrosation of phenol?

When phenol reacts with nitrous acid ($\ce{NaNO2 + \mathrm{conc}\ H2SO4}$), 4-nitrosophenol and not 2-nitrosophenol is formed. I cannot understand why the para-isomer should be preferred over the ...
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0answers
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How much oxygen is used up by the browning of an apple?

This is inspired by a recent popular question on Cooking. Let's assume that I take some apples, cut them up, and place them in a hermetically sealed container. Then the container goes into the fridge. ...
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2answers
1k views

Benzene to phenol in a single step

My teacher told me we can convert benzene to phenol within a single step using $\ce{V2O5}$/ $\ce{O2}$ at 300 ⁰C (not 500 ⁰C). Later I searched for that reaction but I couldn't find it in all over ...
4
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2answers
5k views

Hyperconjugation in cresol

In cresol both $+I$ effect as well as hyperconjugation work together to determine its acidity. When the methyl group is present in the ortho- and para-position both of them can act upon phenol. ...
4
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1answer
3k views

Activity of different positions in phenol with respect to electrophilic aromatic substitution

Which of the statements below is correct? a) The ortho and para positions are more active than the meta position. or b) The ortho and para positions are activated while the meta position is ...
4
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1answer
229 views

Why does orthocresol behave as a skin irritant?

o-Cresol or ortho-Cresol or 2-methylphenol is a constituent of tobacco smoke, and, like most other phenols, behaves as a skin irritant, causing a burning sensation when it comes in direct contact, or ...
4
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0answers
563 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 ...