Questions tagged [halogenation]
For reactions involving the formation of a C-X bond.
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Why does Fluorine react differently than other halogens during Hydrohalogenation/Halogenation and also substitution with Alkanes?
From what I understand, during halogenation with an alkene or alkyne, diatomic gaseous halogen molecules can effectively 'break' the pi bond to produce a haloalkane/haloalkene. However I discovered ...
1
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1answer
42 views
Why do radical inhibitors inhibit a reaction by creating a "more stable" radical, but for monohalogenation, we WANT to form the most stable radical?
According to my notes, radical inhibitors tend to turn a more reactive radical into a less reactive radical by making it more stable. For instance, the hydroquinone reacts with a radical species, ...
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0answers
22 views
Why we can use ΔH to determine reaction rate in free radical bromination reaction steps?
I am trying to understand why we can use ΔH to determine reaction rate in this a free radical halogenation reaction.
Given:
(CH3)2CH2 + Br• → (CH3)2CH• + HBr = 397 - 368 = +29 kJ/mol = ΔH
(CH3)2CH• + ...
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2answers
192 views
What is the major product of the reaction between 1‐methylcyclohex‐1‐ene and BrCl? [closed]
Would the bromine add to the more substituted carbon due to selectivity?
2
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1answer
91 views
Product of reaction between cyclohexene and bromine in methanol at 273 K
What product could we expect when we let cyclohexene react with an equivalent of bromine in methanol at 0 °C? Is it just the trans-addition of bromine (rac.) or also the SN1-susbtitution on a carbon ...
3
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1answer
141 views
Why is carbon tetrachloride more stable than methane?
When a mixture of methane and chlorine is exposed to ultraviolet light – typically sunlight – a substitution reaction occurs and the organic product is chloromethane. However, the reaction doesn't ...
2
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0answers
46 views
Why aren't both alpha-carbons halogenated when acetone reacts with chlorine under UV?
My book shows the following reaction:
Why is only one alpha carbon halogenated? I googled, but couldn’t find anything on it.
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42 views
Number of products formed in radical chlorination on a chiral center
If an organic compound with a chiral center of a specific (R) or (S) configuration, is chlorinated on that carbon center through a radical mechanism, will one product be formed or two? Basically will ...
7
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1answer
102 views
Possibility of further chlorination of hexachlorocyclohexane
The reaction of benzene with excess of chlorine in the presence of sunlight produces 1,2,3,4,5,6-hexachlorocyclohexane as the major product. This is also given in the preparation section of the ...
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107 views
Why is chlorosulfite a good leaving group?
I came across the following website article[1]:
I understand the mechanism and also get the fact that this is nothing but an experimental result but why does the $\ce{ClSOO-}$ group departs ...
1
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1answer
254 views
Bond Polarity vs bond length's effect on reactivity of haloalkanes
My textbook says:
Carbon acquires partial positive charge whereas halogen acquires partial negative charge. Halogen becomes nucleophilic in character, which can be replaced by another nucleophile on ...
1
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2answers
183 views
Why do resorcinol and iodine react to give 2-iodobenzen-1,3-diol?
I am supposed to perform the above shown reaction in the lab soon, but I don't really understand the mechanism behind it. I got told by my lab assistant that the mechanism is an electrophilic aromatic ...
3
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0answers
50 views
What happens when tran-2-butene reacts with aqueous bromine in the presence of chloride?
$\ce{Br2-H2O}$, containing some $\ce{NaCl,AlCl3}$ ?
I initially though that there would be anti addition of Br and OH to give 3-Bromobutan-2-ol but then I also got the intuition that NaCl might ...
4
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0answers
52 views
Does the chlorination of 4-methylcyclopentene generate two enantiomers or two diastereomers?
Does the chlorination of 4-methylcyclopentene generate two enantiomers or two diastereomers?
I think it makes two enantiomers (or one pair of enantiomer) since the starting compound is achiral, but ...
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1answer
167 views
What would be the major products of this reaction?
Obviously, A would be 3-Bromoo 3-methyl cyclo hexene:
as the stable free radical intermediate would be formed.
But B is what I am having problems with. I read that $\ce{LiAlH4}$ forms alkenes with ...
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1answer
67 views
Is the polarisation of halogens of higher atomic number easier because the electrons are further away from its core?
This question concerns the dihalo addition reactions. I've learned that a halogen molecule (which, of course, consists of two atoms of the respective halogen) is more easily polarised by the double ...
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Exception to haloform reaction
While explaining haloform reaction my teacher told me that Me3C-(C=O)-CH3 does not give haloform reaction.
What is the reason behind it since it does have a CH3 group?
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Halogenation by Phosphorous tribromide vs using HBr
My textbook introduced PBr3 by stating that it leads to an inversion in stereochemistry since it always goes through an SN2 pathway, unlike using HBr.
My question is that since Br- is a reasonably ...
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1answer
58 views
Halogens chemical reactions with each other [closed]
https://en.wikipedia.org/wiki/Halogen
Can Halogens react with each other?
Examples :
Chlorine + Flourine
Flourine + Iodine
Iodine + Bromine
Chlorine + Bromine
and so on.
Permutations and Combinations.
...
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0answers
70 views
What makes a good chlorinating agent?
From what I know, good inorganic chlorinating agents, $\ce{SOCl2, PCl3, PCl5}$ are able to substitute a poorer leaving group (like $\ce{OH-}$) for chlorine. For example, for substitution of the ...
4
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1answer
501 views
Safest way to conduct a reaction with bromine under reflux conditions
I am conducting an electrophilic aromatic bromination reaction according to literature. The substrate and intended substitution pattern do not matter, but the reported procedure requires the dropwise ...
1
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1answer
241 views
sp2 hybridisation of alkyl radicals causing formation of racemic mixture
What I know about $\ce{^{.}CR3}$ radical is that it has both $\ce{sp^2}$ and $\ce{sp^3}$ character but the $\ce{sp^2}$ character dominates and so the radical is $\ce{sp^2}$ in nature.
So, suppose we ...
1
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0answers
81 views
Problem encountered during high school unsaturated fats experiment
To get straight to the point, my chemistry experiment was looking at the amount of unsaturated fats in avocado oil with respect to temperature. I did this by testing for the $\ce{C=O}$ bonds using ...
2
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0answers
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why the terminal Br/Cl is an electrophile in AlBr5/AlCl5 complex? [closed]
In halogenation of benzene, e.g. bromination, $\ce{AlBr3}$ and $\ce{Br2}$ is added in order to make $\ce{Br+}$ by forming delivery agent $\ce{AlBr5}$ (step 2 of picture).
Why is the terminal (...
3
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1answer
627 views
Total number of isomers formed on monobromination of 2-methylbutane
What is the total number of isomers formed on monobromination of 2-methylbutane (including configurational and stereoisomers)?
I tried working it out. However, I found only five:
According to the ...
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1answer
79 views
Why 4‐methylidenespiro[2.4]heptane cannot be converted to 1‐chlorobicyclo[3.2.0]heptane? [closed]
According to the solution, the following reaction is not correct:
But why? I have tried solving in the following steps:
Forming a carbocation by breaking the double bond.
Expanding the ring.
...
2
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0answers
99 views
Where will halogenation take place?
In the following halogenation reaction:
At which position will halogenation take place?
It is obvious that the halogenation will take place at a 3° Carbon atom (the rates of halogenation for ...
1
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1answer
171 views
Reaction Mechanisms: Free Radical Halogenation
In Free Radical halogenation using chlorine and sunlight, why does the chlorine-free radical get attached to the allylic carbon?
Will it be correct to say that it follows the anti-Markovnikov rule?
...
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1answer
100 views
Can iodine replace other halogen as well?
While reading about halogen family I encountered the reaction:
$$\ce{NaClO3 + I2 -> NaIO3 + Cl2}$$
I know that that the oxidizing tendency of halogens decreases down the group, so I think that the ...
1
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2answers
468 views
In free radical substitution of propane with halogens, how do you know which carbon ends up with an unpaired electron after fission of C-H bond? [duplicate]
In free radical substitution of propane with a halogen (eg- chlorine), how do you know which carbon out of the three ends up with an unpaired electron after fission of C-H bond?
This image shows ...
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2answers
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Does halogen addition occur without sunlight [closed]
Can this reaction occur;
(2-Bromopentane) + Br2 --(300°C)--> (2,3-Dibromopentane)
As far as I know, halogenation can only occur in UV or sunlight, not with just a high temperature. So how does this ...
2
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1answer
83 views
Reaction of octahydroazecine with iodine crystals [closed]
I really don’t understand why the following reaction would take place first of all.
So this is a sub part of a question wherein we have to compare the basicity of the compounds formed through some ...
3
votes
2answers
421 views
Deriving rate law from a reaction mechanism for a chain reaction using steady-state approximation
I am trying to derive the overall rate equation for the photocatalysed halogenation (chlorination) of an alkane that proceed via this 4 step chain reaction:
$\ce{Cl2->2Cl^. \quad(1) initiation}$
$\...
4
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2answers
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Halogenation of 4‐methylcyclohex‐1‐ene
My problem is with the methyl group. If it wasn't there, I had no problem.
When the halonium bridge is made does the methyl group shift to give a more stable transition state or not?
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1answer
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What is the mechanism for trans-stilbene to stilbene dibromide?
What is the mechanism for trans-stilbene to stilbene dibromide?
This is what I know:
The bond between the hydrogen and bromine is broken and the bromine is given a negative charge, while the $\ce{H}$...
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1answer
1k views
Can sulfuric acid attack a hydrocarbon/paraffin? Under what conditions? [closed]
Sulfuric acid can attack benzene and other hydrocarbons (when mixed with hydrogen peroxide). Also, chlorine gas and bromine can replace hydrogen(s) in hydrocarbons like methane, ethane, propane,butane ...
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1answer
438 views
Bromination of an alkene in presence of water
Bromination of an alkene in presence of water results in its mechanism in a cyclic bromonium ion and "afterwards $\ce{H2O}$ binds to the carbon atom surrounded by more electron donating groups."
This ...
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38 views
Will a Lewis acid catalyze the reaction of HBr with primary alcohols?
It is well-established that a Lewis acid catalyst (popularly $\ce{ZnCl2})$ is necessary to form an alkyl chloride when reacting $\ce{HCl}$ with a primary alcohol. This actually changes the mechanism: ...
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1answer
311 views
Mechanism of 5‐(iodomethyl)oxolan‐2‐one synthesis from 4‐pentenoic acid and iodine in acetonitrile [closed]
There is a question in my organic chemistry textbook with an answer. What it doesn't explain (and neither does my theory textbook, I checked) is the mechanism involved in the reaction. The reaction is ...
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1answer
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How many products does this reaction yield?
How many products can we get from the monochlorination of 2,4-dimethylpentane including stereoisomerism? I have seen someone say that it yields 3 structural isomers one of which has two enantiomers ...
2
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1answer
986 views
Di-alpha-halogenation of ketones in acidic medium
I was studying alpha-halogenation of ketones from LibreTexts Chemistry,
Under acidic conditions the reaction occurs through the formation of an enol which then reacts with the halogen${^1}$.
1) ...
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0answers
279 views
Does acetophenone show haloform reaction?
Although acetophenone is a methyl ketone, as it is aromatic, it is immiscible in H2O so the last step in the haloform reaction should not occur?
I couldn't find any source regarding the haloform ...
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1answer
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What happens when HCl is added to acetylene in presence of mercuric ions?
Normal addition of Hydrochloric Acid to acetylene would give me a 1,1 Dichloro product.
But I read that in presence of mercuric ions only one molecule of HCl is added to give Vinyl Chloride.
Why does ...
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1answer
570 views
Reaction between phenylamine and halogens
I understand that phenylamine is considerably more reactive than benzene, meaning that it is able to react with bromine water to give 2,3,6-tribromophenylamine. But I was then wondering why I haven't ...
5
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3answers
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Mechanism with hypohalite in haloform reaction
The haloform reaction is usually done in a solution of NaOH and $\ce{I2}$ (or indeed, any halogen). Now the first part of the reaction mechanism in the wikipedia page and in the most organic books ...
4
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2answers
139 views
Finding major product when bromonium compound is acted upon by a nucleophile
The original question is:-
The major product obtained in the following conversion is:-
(Note that Me here means methyl group)
The initial step would be the formation of a bromonium ...
1
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1answer
3k views
Which will be the major monochlorination product? [closed]
Which of these compounds represents the major monochlorination isomer formed in the following reaction?
According to selectivity theory, the answer should be (c). However, the given answer is (b).
4
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1answer
7k views
What is the rate-determining step in free radical halogenation?
Recently, we were learning about free radical halogenation in school. A set of notes given to us wrote that the rate-determining step is the propagation step. This seems to go against my understanding ...
2
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1answer
628 views
Bromination with NBS on cyclic structures
I found this question and the answer as shown in my book. I didn't understand why the bromine particularly entered the position shown in the answer.
First of all, if a free radical was generated ...
7
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1answer
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Why is free radical chlorination exothermic whereas bromination is endothermic?
In the energy profile diagrams below, it can be clearly seen that the free radical chlorination of an alkane
$$\ce{RH + Cl2 -> RCl + HCl}$$
is exothermic. However, the corresponding bromination
$...
