New answers tagged alcohols
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A basic principle in OChem says that stability of intermediate is the key factor in deciding the major product, in general. Another factor is stability of final product.
Will a kinetically favoured (minor) product (c) form?
It will form, as far as it's intermediate is known to exist (and it exists). However, that will be present in very minor amount, as ...
1
Pathway 2 is unlikely. The tert-butyl group stays put, i.e., it remains attached to the same carbon throughout the reaction. It is the rest of the molecule that rearranges. The mechanism of this reaction was demonstrated 70 years ago. Compare this reaction with Possible nonclassical ion from a bicyclic system on ChemSE. There is information at the link on ...
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I'd say your mechanism is acceptable. However, the final product, pentafulvene (PIN: 5-Methylidenecyclopenta-1,3-diene) is said to be not stable at room temperature. Generally, fulvenes are thermally unstable, sensitive to oxygen and photosensitive (Ref.1). They are also prone to acid- and cation-catalysed polymerisations. For example, there have been ...
2
You have misinterpreted what Wikipedia has said. I'd put whole quote here:
Cyclobutadiene is an organic compound with the formula $\ce{C4H4}$. It is very reactive owing to its tendency to dimerize. Although the parent compound has not been isolated, some substituted derivatives are robust and a single molecule of cyclobutadiene is quite stable. Since the ...
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In real-life, Cyclobutadiene dimerizes at temperatures above 35 K by a Diels-Alder reaction (source: Wikipedia). However, this seems more like a theoretical reaction rather than a practical one, so treat it as such and stick to the task of finding the dehydration product of this cyclobutadiene derivative.
Yes, this step is correct (although the arrow-pushing ...
0
Dissolve non iodine table salt into a known amount and let it sit, measure the amount of water that sits in the bottom compared to the amount of alcohol that is in the top after about 10-15 minutes of sitting. You can then extrapolate what percentage of alcohol you bought. Example would be about half water and half alcohol if you got 50% isopropyl alcohol.
3
The mechanism should provide for the successive processes of carbocation formation, rearrangement and proton loss.
Observations(Points to consider):
The tendency to attain stablity by aromaticity.
The high ring strain in the cyclobutane ring.
The first step step should involve protonation of each hydroxy group attached. Protonation produces hydronium ion ...
10
Seeing the reaction given here, I assume that is an on-paper reaction that takes place and that all three alcoholic groups are dehydrated.
The mechanism (on paper) seems to be as follows
Dehydration $1$
For the first dehydration, the carbocation formed is stabilised via ring expansion and then forms a double bond as follows:
Dehydration $2$
Similar to the ...
10
Nilay's answer, as well as the comments, do a great job of explaining why methanol is toxic (and ethanol is comparatively less toxic). I'll take a different approach here: I'll explain why ethanol is the major component of alcoholic drinks. To start off, ethanol is not the only alcohol in alcoholic drinks1. Other alcohols such as Glycerol, Tryptophol, Tert-...
27
The problem arises from the metabolized products of methanol. Methanol oxidizes in the liver by an enzyme called alcohol dehydrogenase to formaldehyde which is further metabolized to formic acid by another enzyme called aldehyde dehydrogenase. This formic acid is the source for acute toxicity associated with methanol poisoning. Accumulation of this chemical ...
0
In a typical acid-catalyzed dehydration, the reaction goes by an SN1 mechanism, and the rate-limiting step is
$$\ce{R-OH2+ -> R+ + H2O}$$
The rate of this step is typically a function of the stability of the cation product. In your case, the secondary cation formed from isopropanol is more stable than the primary cation formed from n-propanol.
I'm using &...
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The other answer by permeakra is sufficient and complete. But, I'd like to add an explanation on how
"A carbonyl group normally destabilizes carbocations but stabilizes carbanions"
For instance, someone can think that the carbocation would resonate with the carbonyl group as what we've learnt earlier, I'd also thought in that way, initially. But, ...
7
A carbonyl group normally destabilizes carbocations but stabilizes carbanions.
In this particular case, the rate of dehydration isn't guarded by carbocation stability, but by CH- acidity. In acidic conditions, OH group in alcohols is relatively easily protonated. Then, if there is a relatively acidic hydrogen in $\beta$-position it immediately dissociates, ...
2
Polyethylene (polythene, to some) may have plasticizers, such as adipates, terephthalates, or phthalates, but they are not inherently needed in all cases. Hopefully, the supplier of those alcohols does not bottle them in cntainers with plasticizers, but a wash bottle, purchased separately, might very well have them added to the plastic, particularly because ...
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Be aware that alcohol has 2 main meanings:
alcohol(1) = ethanol / ethylalcohol / drinking alcohol
alcohol(2) = organic compound containing alcoholic group $\ce{-OH}$ bound to non aromatic carbon atom. Such compounds have usually names ending by -ol, unless empirical names take preference.
Similarly as palm oil is just one of many kinds of fat ( esters of ...
1
Ethanol is the compound that goes against teetotaling. Otherwise, all sugary foods are alcoholic, carbohydrates are alcoholic and what else.
Alcohols are defined as organic hydrocarbons containing the hydroxyl group ( the OH group.). So sugar is an alcohol; it has a hydroxyl group.
Thus, only ethanol is the compound responsible for intoxication and going ...
4
For this question, given the lack of initial information, I'm making the following assumptions:
Butane-2,3-diol dehydrates to give butan-2-one
2-butanol dehydrates to give but-2-ene
Butane-2,3-diol dehydration is nicely described in this paper from Emerson1:
Aqueous 2,3-butanediol was shown to react in a pseudo-first-order reaction in the presence of ...
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