Questions tagged [alcohols]
For questions about saturated and unsaturated alcohols, their physical properties, their reactions, etc. For questions about phenol, use the [phenols] tag instead.
71
questions
27
votes
2
answers
122k
views
Reaction of alcohols with PCl5 and PCl3
The reaction of alcohols $\ce{ ROH }$ with $\ce{ PCl5 }$ and $\ce{ PCl3 }$ yields an alkyl halide $\ce{RCl}.$ With $\ce{ PCl5 }$, the reaction is quite simple leading to the formation of $\ce{ RCl }$ ...
- 2,044
14
votes
4
answers
13k
views
Why can't alcohols form hydrogen-bonded dimers like carboxylic acids?
Carboxylic acids such as acetic acid are capable of forming dimers:
I'm wondering why alcohols like ethanol don't generally form dimers. In the diagram below, the oxygen atom on the left ethanol ...
- 467
22
votes
3
answers
49k
views
Migratory aptitude in pinacol-pinacolone rearrangement
I am confused about the migratory aptitude of various groups, as there are many different orders for the same given in different places, especially about -Ph and -H. I would like to know if someone ...
- 3,846
17
votes
2
answers
49k
views
Reactions of alcohol with sulfuric acid
I knew two chemical reactions of alcohol with sulfuric acid
$\ce{CH3CH2OH + H2SO4 -> CH2CH2}$
Here product is having a double bond (ethene) and this reaction happens at 443 K temperature.
$\ce{...
- 734
5
votes
1
answer
11k
views
Mechanism for oxidation of primary alcohols to carboxylic acids
My teacher told me that the following is the mechanism for oxidation of primary alcohols to carboxylic acids:
I've searched in books and online and didn't find a similar mechanism. For example, in ...
- 393
13
votes
2
answers
2k
views
How do I predict the solubility of a compound in a mixture of water and an organic co-solvent?
I'm trying to predict the solubility of long alcohols (e.g. 1-octanol, 1-decanol or 1-dodecanol) in a mixture of water and an organic co-solvent such as DMSO, acetonitrile or ethyl acetate.
For ...
11
votes
2
answers
4k
views
Is methanol really more acidic than water?
The question Why is methanol more acidic than water? deals with the reasoning of why methanol is more acidic than water. However, as mentioned in the comments of that question, the acidity constant of ...
- 1,438
4
votes
1
answer
1k
views
Is Pinacol rearrangement the source for the ring expansion?
I have no idea what's happening as in the product (the answer is (a)) there is a new ring being formed on the left benzene. But as I studied after $\ce{H2O}$ leaves, a carbocation is then formed on ...
8
votes
2
answers
3k
views
Saturation of multiple solutes
Can a liquid which is saturated with a single solute, dissolve a different solute, or is saturation a universal thing? I ask because I’ve seen that different solutes have different points (amounts) at ...
- 191
5
votes
2
answers
5k
views
Reaction of ethylene glycol with PI₃ (P + I₂)
We know that $\ce{2P + 3I2 -> 2PI3}$
Ethylene glycol reacts with $\ce{PCl3}$ to give ethylene dichloride, but why does it gives ethylene when it reacts with $\ce{P + I2}$?
I don't really know ...
- 1,429
4
votes
1
answer
4k
views
Halogenation of alcohols in the presence of ZnCl2
I know that $\ce{OH-}$ is usually a bad leaving group, but why does the following reaction occur via SN1 in presence of anhydrous $\ce{ZnCl2}$?
- 853
44
votes
1
answer
89k
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 ...
- 559
17
votes
1
answer
961
views
Can we synthesize alcohols by the photolysis of hydrogen peroxide?
As I was going through my revision of organic chemistry, I came across free radical substitution of alkanes with halogens. In a similar process where we use hydrogen peroxide, instead of chlorine, so ...
13
votes
1
answer
19k
views
Reaction of secondary alcohol with ammoniacal silver nitrate (Tollens' reagent)
What are the products of the reaction of 2-butanol with silver nitrate?
For the moment, I am a bit stumped as I only have $\ce{AgNO3}$ as an oxidizing agent to form a carboxylic acid from an aldehyde....
- 565
13
votes
4
answers
29k
views
Why do hydroxyl groups only produce a singlet in proton NMR?
Take, for example, methanol ($\ce{CH3OH}$). The hydroxyl proton ($\ce{-O$\color{red}{\ce{H}}$}$) is three bonds away from three more protons ($\ce{-C$\color{blue}{\ce{H}}$_3}$), which aren't ...
- 443
12
votes
3
answers
12k
views
Why do tosylation and mesylation of alcohols follow different mechanisms?
Why do the tosylation and mesylation of an alcohol proceed via different mechanisms?
More specifically,
In tosylation, the lone pair of the alcohol attacks the sulfur in TsCl, but why does it not ...
- 651
12
votes
2
answers
4k
views
Why is the melting point of tert-butyl alcohol 140 °C higher than that of sec-butyl alcohol?
This is one of the most drastic differences in a physical property I've ever seen for two such similar molecules, and in a simplistic sense anyway the difference lies in the opposite direction from ...
- 17.4k
10
votes
3
answers
477
views
Have "molecular clusters" for azeotropes been identified?
A different question about azeotropes got me thinking about this point again. Azeotropes have a very specific composition so it seems that the azeotrope ought to have some sort of physical structure. ...
- 22.3k
8
votes
2
answers
2k
views
False positive in lucas test for primary alcohol due to formation of tertiary carbocation by rearrangement?
From Wikipedia:
The Lucas test in alcohols is a test to differentiate between primary, secondary, and tertiary alcohols. It is based on the differences in reactivity of the three classes of alcohols ...
- 193
7
votes
2
answers
2k
views
Benzene from cyclopropane-1,2,3-triyltrimethanol in acidic medium
What is the mechanism of the conversion of cyclopropane-1,2,3-triyltrimethanol to benzene in in acidic medium?
After performing E1 thrice I was expecting 1,2,3-trimethylidenecyclopropane to form ...
- 5,375
7
votes
4
answers
47k
views
How does the inductive effect, explain the reactivity of tertiary alcohols with halogen acids?
The reactions of primary and secondary alcohols with halogen acids ($\ce{HX}$, where $\ce{X}$=halogen) require the presence of a catalyst, $\ce{ZnCl_2}$. With tertiary alcohols, the reaction is ...
- 2,326
7
votes
4
answers
13k
views
Why don't alcohols undergo nucleophilic substitution with ammonia?
Alcohols can undergo nucleophilic substitution with $\ce{PCl5, POCl3, HCl}$. Halogenoalkanes can undergo nucleophilic substitution with $\ce{NH3}$. The $\ce{C-O}$ (in alcohol) and $\ce{C-Cl}$ (in ...
- 639
6
votes
2
answers
707
views
Formation of toluene from (cyclobutane-1,2,3-triyl)trimethanol using conc. sulphuric acid
In my book this reaction is given without any mechanism:
I thought that simple dehydration reaction is going to take place with rearrangement of the carbocation but I have no idea as to how toluene ...
- 363
5
votes
1
answer
2k
views
Phenol or ethanol as a nucleophile for ether formation?
If we react phenol with $\ce{C2H5I}$ in $\ce{C2H5O- Na+}$ (excess), $\ce{C2H5OH}$ (anhydrous) solutions .
In this reaction why is diethyl ether not formed and the actual product is phenyl ethyl ...
- 493
5
votes
5
answers
4k
views
What is the OH in alcohol?
What is the $\ce{OH}$ functional group in alcohol (ethanol)? My teacher told me it isn't the same as the $\ce{OH-}$ ion or hydroxide.
But it does donate one electron to the respective carbon chain and ...
- 983
4
votes
2
answers
1k
views
Why and how does ring expansion occur in the dehydration of (cyclobut-3-ene-1,2-diyl)dimethanol?
Can someone explain how does this ring expansion occur with the mechanism? I do understand that the hydride shift occurred because of carbocation stability but why did the ring expand? Can you please ...
- 141
3
votes
2
answers
452
views
Rate of dehydration of alcohols having keto group
The following question was asked in IITJEE-Screening 2000,
Which of the following will be most readily dehydrated in acidic conditions?
I thought that the answer would simply be (c), as its ...
- 3,033
2
votes
1
answer
2k
views
Oxidation of alcohols by Ceric Ammonium Nitrate
I have realized that reaction with ceric ammonium nitrate essentially results in coordination of alcohol with $\ce{Ce(IV)}$ and my teacher referred that we should be able to proceed it to form ketone ...
- 1,514
1
vote
1
answer
1k
views
What is more important, to have the parent chain be the cycle or the chain that has an hydroxyl group
I know how to name alcohols, I just don't know what I should chose as the parent chain. Should I chose the cycle or the chain with the hydroxyl group. Here is an example:
My current algorithm tells ...
- 177
1
vote
1
answer
1k
views
Why does the reaction of the primary alcohol cyclopentylmethanol with hydrogen bromide follow SN1 mechanism?
Example 2: Identify all the products formed in the following reaction and indicate the major product.
Solution: Three products will be formed in the given reaction as shown below:
In this reaction ...
- 67
-2
votes
1
answer
128
views
Rearrangement of 8a-ethyl-1,3,4,8a-tetrahydronaphthalen-4a(2H)-ol [closed]
really sorry for that previous post. I was actually half-asleep when I posted that q, hence the q was unclear. I am again reposting that question
The answer is given as A. Can anyone please explain ...
- 159
14
votes
4
answers
63k
views
How do you create primary amines from alcohols?
By a primary amine I mean a compound where the hydroxyl group of the corresponding alcohol is replaced with an amine group.
- 2,443
13
votes
1
answer
9k
views
Ring contraction in pinacol rearrangement of cyclohexane-1,2-diol
I came across this question in three different textbooks.
The question was: What is the major product obtained on dehydration (treatment with concentrated $\ce{H2SO4}$) of cyclohexane-1,2-diol.
I ...
- 1,112
11
votes
1
answer
303
views
Which electronic effects are responsible for the reduction of nucleophilicity of a hydroxy group orthogonal to an ester?
I am facing a similar synthetic problem as Boekman Jr. et al noted in their synthesis of Tetronolide.[1] I will quote their’s rather than disclosing my actual synthetic problem, but note that the key ...
- 67.3k
10
votes
2
answers
30k
views
Why is thionyl chloride preferred for preparing alkyl chlorides from alcohols?
Why is thionyl chloride ($\ce{SOCl2}$) preferred for preparing alkyl chlorides from alcohols, as opposed to say $\ce{PCl5}$ or $\ce{PCl3}$ ?
- 123
9
votes
1
answer
2k
views
How could alcohol be made into a powder?
In the news recently is 'Palcohol', powdered alcohol, that you add to water or existing liquids to make it alcohol. Presumably this would dissolve and break apart into alcohol and {some other compound}...
- 532
8
votes
2
answers
1k
views
Producing ketones from secondary alcohols using hydrogen peroxide
Usually, to produce ketones from secondary alcohols (e.g. propanone from 2-propanol), people use a solution of potassium or sodium dichromate with a small amount of sulfuric acid. Can other oxidizers ...
- 1,473
8
votes
1
answer
1k
views
Mechanism for bromoetherification of olefinic alcohol
Propose a mechanism for the following reaction showing the relevant stereochemistry of intermediates and the final product.
I am confused as to what is going on here. I guess there's some sort of ...
- 1,451
8
votes
2
answers
4k
views
How does SO2Cl2 react with alcohols?
Is the mechanism similar to the reaction of $\ce{SOCl2}$ with alcohols?
If not, then how is it different? We have been taught about the latter at school but my friend quizzed me about $\ce{SO2Cl2}$.
...
- 89
7
votes
2
answers
1k
views
Do amines or alcohols have stronger intermolecular hydrogen bonds?
Which has stronger hydrogen bonding, $\ce{CH3OH}$ or $\ce{CH3NH2}$
I think it comes down to which has more dominance; number of hydrogens, number of lone pairs, or electronegativity.
- 1,021
6
votes
1
answer
2k
views
Protonation of tetrahydrofurfuryl alcohol
I think the ethereal oxygen in THFA gets protonated. Due to greater +I effect, the electron density on it is higher, hence it is more likely to behave as a Lewis base. Consequently, the product formed ...
- 69
6
votes
2
answers
216
views
How to find trace methanol content in fermented fruit/distillate?
Suppose we have some fermented (optionally also distilled) fruit/fruit juice. The sample therefore contains water, sugars, ethanol etc. Which analysis method is the simplest to find out whether the ...
- 61
6
votes
1
answer
10k
views
Why are 1,3-diols protected with aldehydes but 1,2-diols are protected with ketones?
1,3 diols are usually reacted with benzaldehyde when protection of the OH groups is desirable, but acetone is used when the relation between the hydroxyl groups is 1,2. Why is it so?
- 14.2k
6
votes
1
answer
2k
views
Electrolysis of Beer
Electrolysis of water, means that the water is separated into hydrogen and oxygen. As beer also includes water, I initially thought electrolysis of beer would cause the water to separate, and the ...
- 161
6
votes
2
answers
3k
views
Why is the Lucas test not recommended to differentiate higher alcohols?
I read about the Lucas test for alcohols in which a cloudy precipitate is produced with a tertiary or secondary alcohol. However, on a side note it was mentioned that this test is useful only for ...
user78585
5
votes
3
answers
12k
views
RO (alkoxide) as a leaving group
Why is RO (alkoxide) a better leaving group than OH, despite RO being more unstable due to the electron donating effect of the alkyl group on RO?
I read that the suitability of leaving groups is ...
- 1,451
5
votes
3
answers
8k
views
Solubility of methanol and ethanol in water
Which substance is the most soluble in water?
$\ce{CH3OH}$
$\ce{CH4}$
$\ce{C2H6}$
$\ce{C2H5OH}$
I wasn't able to decide between 1 and 4, as both have hydroxides, but the answer is 1. ...
5
votes
1
answer
1k
views
Purification of Ethanol
In Vogel's organic book, they have mentioned that in the Lund and Bjerrum method of purification of ethanol, magnesium is added, which forms ethanolate. But they said to activate the magnesium first ...
user14874
5
votes
2
answers
1k
views
Rate of O exchange with H2O
We have to find the order of rate of exchange of O with H2O of the following compounds
$\ce{CCl3CHO}$
$\ce{CH3CHO}$
$\ce{CH3COCH3}$
$\ce{CF3CHO}$
According to me, higher rates of exchange would be ...
- 493
4
votes
6
answers
7k
views
Storage of Urine
Not all may be favorable to this project, but I will explain what I am trying to do. I work at home, and instead of walking a moderate distance to the bathroom and loosing my focus, I've been, at ...
- 151