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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Stability and Reactivity of Phenoxide

Phenoxide is supposed to be more stable than phenol because it has more stable resonance structures. And stable stuff is supposed to be less reactive. But my textbook says that Kolbe's Reaction of ...
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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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Fries Rearrangement Products

During Fries Rearrangement, oxygen donates its lone pair to $\ce{AlCl_3}$ forming $\ce{-O^+-AlCl3}$. Since this is a strong electron withdrawing group, shouldn't the final product be meta-substituted?
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Phenoquinone vs benzoquinone [closed]

Are phenoquinone and benzoquinone the same thing? When I searched for the colour of benzoquinone I found that it's yellow. But when I searched oxidation of phenol in air. It states that it turns pink/...
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ortho/para-Selectivity in the Reimer-Tiemann Reaction [duplicate]

I can't figure out why the dichlorocarbene molecule produced in the Reimer-Tiemann reaction gets attached to the ortho position of phenol. The ortho position is sterically slightly more hindered due ...
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191 views

Why does p-nitrophenol give sodium bicarbonate test, but o-nitrophenol does not?

Both ortho- and para-nitrophenol are less acidic than carbonic acid. But still paranitrophenol reacts with sodium bicarbonate to give carbonic acid and sodium paranitrophenoxide. However, this is not ...
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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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2answers
923 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 ...
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1answer
50 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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102 views

Why does cinnamaldehyde pass the ferric chloride test?

I was given some data to determine what the unknown compound was and figured out that it was cinnamaldehyde. After reviewing the classification test given to me by my professor, I was a bit confused ...
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55 views

Are Phenol and Alchohol both hydrocarbons? [closed]

In many books there are said that Alchohols are hydrocarbons, and some says they are not. On the other hand Phenols are said aromatic hydrocarbons. It is well known that Phenols are not Alchohol. ...
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Acidity order of o-nitrophenol vs. o-chlorophenol [closed]

It is given that the above statement is true. Why does o-nitrophenol, in spite of intramolecular hydrogen bonding, have a lower $\mathrm{p}K_\mathrm{a}$ than o-chlorophenol?
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How does the relative acidity of 2,3-dinitrophenol compare to that of 2,4-dinitrophenol?

I am assuming that the -I inductive effect in 2,3-dinitrophenol is stronger than in 2,4-dinitrophenol since it operates through less bonds, therefore on inductive grounds it should have a lower $\...
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1answer
103 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 ...
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Acidic strength of phenol derivatives

While comparing the strengths of o-nitrophenol and p-nitrophenol, p-nitrophenol is found to be more acidic. The reason I studied for this is $\ce{H}$-bonding in o-nitrophenol which makes the acid more ...
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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 ...
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259 views

Which compounds react positively in the aniline dye test?

I read that to test for the presence of phenol groups in an organic compound the aniline dye test can be performed. If the solution has phenol present it gives a red or orange precipitate to confirm ...
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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 ...
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2k views

what is mechanism for reaction phenol + dimethylsulphate -> anisole

Dimethyl sulphate breaks the oh bond and forms anisole. How does the reaction proceed?? is it oxygen lone pair attacks on sulphur which has partial positive charge?? the reaction takes place in ...
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Extraction between cyanex 923 and phenol

I want to remove phenol from wastewater so I used the cyanex923 as an extractant or carrier to extract phenol from the wastewater (the name of the process is non-dispersive solvent extraction) but the ...
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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 ...
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1answer
257 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 ...
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1answer
294 views

Equilibrium Constants For Phenol Tautomers

I encountered the following equilibrium constant values for the keto-enol interconversions of phenol in Organic Chemistry (Solomons, Fryhle, Snyder, 3rd Edition): I wonder what could explain the ...
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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 ...
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Reaction of orthocresol with butyrolactone in presence of AlCl3 and heat

What will be the major product of the following reaction? Please also help me with the mechanism. I'm not sure whether C- acylation or O- acylation will occur here. And if O- acylation does occur, I ...
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Can benzene ring be the part of a acyl group

Can benzene ring attached to c=o i.e carbonyl group be considered as a acyl group?
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Mechanism of oxidation of phenol to quinone by chromium(VI)

In the supplementary information for Org. Lett. 2005, 7 (19), 4297–4300, the following experimental method for the synthesis of 2-bromo-6-methylcyclohexa-2,5-diene-1,4-dione is given: To a ...
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732 views

Converting phenol to para-nitrophenol via nitrosophenol

Our class 12 text book says that if we treat phenol with mixture of concentrated $\ce HNO_3$ and $\ce H_2SO_4$, instead of nitration, the ring is oxidized to quinone. So, the book proposes that we ...
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Addition of NaBH4 and LiAlH4

NaBH4 and LiAlH4 will be a source for the hydride ion and reaction will begin with addition of hydride by displacing the carbonyl group. But I am not sure will it attack both the carbonyl or only one....
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48 views

Are polyhydroquinones considered to be polyphenols?

Looking at the Wikipedia article for polyphenol, I was struck by how the monomer units shown are all substituted meta or ortho for the hydroxyl groups. https://en.wikipedia.org/wiki/Polyphenol#...
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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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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 ...
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Reactivity comparison of phenol and toluene towards electrophilic substitution

Which aromatic compound is more reactive towards electrophilic substitution? benzene chlorobenzene phenol toluene Correct answer: phenol But, according to me, the answer should ...
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797 views

How to determine the order of acidity of the following dimethyl nitrophenols

This is how I went about it, although I got a wrong answer: 3,5-Dimethyl-4-nitrophenol (2) shows the nitro group to be sterically hindered, due to which it should go out of plane and this will be an ...
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342 views

Out of the given reagents, find the ones to be used to convert benzene to p-aminophenol

$\ce{Br2/FeBr3}$ $\ce{CH3Cl/AlCl3}$ $\ce{KMnO4}$ $\ce{HNO3/H2SO4}$ $\ce{NBS}$/hv $\ce{NaOH}$ $\ce{Sn/HCl}$ $\ce{NH4SH}$ $\ce{NaBH4}$ I'm able to get the amino group onto the ring by using 4 and 7. ...
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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 ...
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1answer
753 views

Strong activation of phenoxide ion compared to others

I was told that in phenoxide ion, benzene ring is very strongly activated. The order my teacher told me was phenol < amine < $2^\circ$-amine < $3^\circ$-amine < phenoxide (for activation ...
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reimer tieman reaction only one ortho product [closed]

why we cannot have two reimer tiemann substitutions on the same phenol as CHO- group is electron withdrawing it wont disturb electron concentration at its meta which is phenol's ortho- product
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312 views

Reaction of carbonyl cyclic diene with Grignard reagent

Predict the major product of this reaction: The two compounds on the right are the possibilities that I thought of (weren't given in the question). According to me: attack on carbonyl carbon by $\ce{...
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5k views

Phenol preparation from Grignard reagent

Reaction: Phenyl magnesium bromide in presence of excess oxygen, on acidification yields phenol, as below. My instructor told me that the above reaction occurs, and if the reagent is in excess then ...
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1answer
25k views

Halogenation of Phenol [closed]

Why does only one $\ce{Br+}$ ion get generated in a non-polar solvent (such as $\ce{CS2}$), while more $\ce{Br+}$ ions are generated in aqueous or polar solvent (such as $\ce{H2O}$)?
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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 ...
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2answers
7k views

What is the order of acidic strength among phenol, catechol, resorcinol and hydroquinone?

This question is from a book that gives the answer as $$ \text{hydroquinone} < \text{resorcinol} < \text{phenol} < \text{catechol} $$ but does not provide any explanation for the answer. If ...
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Why is phenol more acidic than aniline?

I find that there are two contradicting factors at play here: 1) On removing proton, negative charge on oxygen is more stable than it is on nitrogen (because of greater electronegativity of oxygen). ...
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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 "...
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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 ...
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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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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 ...
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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. ...
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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)...