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Questions tagged [reaction-mechanism]

The detailed (and as complete as possible) description of plausible or observable pathways leading from reactants to products of a chemical process. This tag should be applied to questions about these processes. It may be applied to hypothetical and/or proposed mechanisms.

365 questions with no upvoted or accepted answers
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14
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1answer
442 views

Why does a Diels–Alder reaction not occur here?

I have recently come across this organic chemistry problem. I thought it would undergo simple Diels–Alder reaction But it didn't turn out to be. The product to me looks like a nucleophilic attack ...
9
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0answers
2k views

Synthesis of Anthracene: Mechanism

Recently, I happened to find a problem that involved the synthesis of anthracene from bromobenzene in the presence of tert-butyl lithium, using THF as the solvent, and at room temperature. I am ...
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158 views

Does a cationic 1,3-triphosphinane react with a methyl cation?

The question is: Reaction of $\ce{Et2P(CH2)3PEt2}\text{ with }\ce{PCl3}$ ($1:1$) in the presence of $\ce{SnCl2}$ gives a ring system A, which exhibits two phosporus NMR resonances, a doublet and a ...
9
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0answers
724 views

Can I make Ferrofluid without evaporating Ammonium?

I want to make ferrofluid, which is ferromagnetic particles suspended in a carrier fluid. Three methods I have seen involve using magnetic ink (for MICR codes), cassette tapes, or ferric chloride as ...
8
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0answers
358 views

Why are two three-membered rings preferred to a single five-membered ring in the reaction of a dihalide with alcoholic KOH?

The given answer is 1,1-dicyclopropylmethanone: Step 1 is abstraction of acidic H by the strong base. Then, there's surely going to be anchimeric assistance. But there can be two places where the ...
8
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1answer
2k views

Role of methanol in NaBH4 reduction

In reduction of carbonyls (aldehyde and ketones) to alcohols using NaBH4/Methanol, alkoxides are formed with the Boron which usually gets protonated on addition of water/acid. My question is what is ...
8
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15k views

Mechanism for an Étard reaction (chromium complex)

In the following reaction, a chromium complex is formed during the Étard reaction: I have the following questions: How is this complex formed? How does its hydrolysis take place? (What's the ...
8
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0answers
278 views

Grubbs, Wittig & hydroboration reactions and Woodward-Hoffmann rules

Several organic mechanisms I know involve [2+2] cycloadditions and retro-[2+2] cycloadditions, namely: The Wittig reaction Hydroboration of an alkene Olefin metathesis (using Grubbs' catalyst) How ...
7
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0answers
741 views

Kinetic Isotopic Effect in EAS

It is observed that rate of reaction of two isotopologues of benzene, $\ce{C6D6}$ and $\ce{C6H6}$, is the same for electrophilic aromatic reactions, as the deprotonation is not the rate limiting step. ...
6
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809 views

Finding theoretical mechanism of sodium thiosulphate and hydrochloric acid

In class we conducted an experiment where we timed reactions between sodium thiosulphate and hydrochloric acid. We kept the concentration of the $\ce{HCl}$ constant, while changing the concentrations ...
6
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0answers
416 views

Treatment of ketones with excess Tebbe reagent

The reaction in black below was presented in a set of lecture notes as an example of the use of the Tebbe reagent, however it's not immediately obvious (to me, at least) that the product should be the ...
6
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0answers
721 views

Mechanism for the decomposition of HI

I've been trying to find the mechanism for the gas phase decomposition of hydrogen iodide: $$\ce{ 2 HI (g) <=> H2 (g) + I2 (g)} $$ Anyone know of sources where I can get information on this? I ...
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296 views

Lemieux-Johnson oxidation on cycles

Consider 5-cyano-2,2-dimethylpentyl 4-methylbenzene-1-sulfonate: What would it yield by a Lemieux-Johonson oxydation ($\ce{OsO4}$, $\ce{NaIO4}$)? My first guess would have been that $\ce{OsO4}$ was ...
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197 views

Solve this chemical or biological mystery

I hope this is the best place to pose this unique question. Please forgive me if it's not. I went into a closet to get a prescription medication that was filled about a year ago. The label on the ...
6
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0answers
387 views

Is there a bifurcation node in the potential energy as a function of reaction progress equation of chemical reactions?

I originally posted a similar question on math.stackexchange.com, but I believe I might have a better chance of having my question answered here after giving it some time. I was thinking about the ...
5
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0answers
302 views

Reaction of cyclopropane with hot potassium permanganate

Hot potassium permanganate is usually used as an oxidising agent, and cyclopropane being an unstable three membered ring undergoes reaction with several reagents such as bromine, $\ce{HBr}$, metal ...
5
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0answers
129 views

How to account for the interface between two different phases in a discretized diffusion model?

I have tried to set up a model for the diffusion of a gas into a liquid. The two media are next to each other and the geometry is spherical because the system should simulate the diffusion out of a ...
5
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0answers
4k views

Oxidation of naphthalene with KMnO4

What is the product when naphthalene is oxidized by alkaline (or acidic) solutions of $\ce{KMnO4}$? Some possible reactions show up in a google search, but they have no references: Naphthalene to ...
5
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0answers
119 views

Which site is more favorable for EAS in O-Acetotoluidide?

Which site is more favorable for electrophilic aromatic substitution in O-Acetotoluidide? The answer given in my textbook says the site para to acetamide group is more favorable, however I believe ...
5
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0answers
7k views

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 ...
5
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106 views

Why does the presence of EWG's on the aryldiazonium ring increase the yield of a Meerwein arylation?

In my textbook, Strategic Applications of Named Reactions in Organic Synthesis, the author says the following regarding properties of the Meerwein arylation: The general features of this reaction ...
5
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0answers
89 views

How to theoretically predict thermodynamic stability?

Let's say we have $\ce{CH3-NH2}$ undergoing Hoffman's exhaustive methylation with $\ce{CH3-Cl}$. In which case side reactions such as $\ce{CH3-NH2 + CH3-NH2 -> CH3NHCH3 + NH3}$ would also occur. ...
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306 views

Cannizzaro reaction of furan

I encountered this question in a competitive exam. Can furan undergo Cannizzaro reaction? I though it can only happen with aldehydes.
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252 views

Compounds that Liberate Hydrogen from Water, Reversibly

I'm working on a paper which provides an overview of all the current methods for storing hydrogen gas as part of a renewable energy system, and I understand compressed gas and metal hydride storage ...
5
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0answers
2k views

Why does reduction of naphthalene with nickel/hydrogen lead to trans-decalin?

Is there any reason why $\ce{H2/Ni}$ leads to trans-decalin? I knew from high school that catalytic hydrogenations are always syn.
5
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0answers
9k views

Mechanism of toluene oxidation with CrO3

What is the mechanism for the following oxidation of toluene with $\ce{CrO3}$ in acetic anhydride? Use of chromic oxide ($\ce{CrO3}$): Toluene or substituted toluene is converted to benzylidene ...
5
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0answers
619 views

Formose reaction - mechanism of first step

The following image was taken from wikkipedia's article about the Formose reaction. What is the mechanism of the first step of the reaction sequence? How do the two formaldehyde molecules condense?
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690 views

Why PI3 is not used in HVZ reaction?

With the help of HVZ reaction, we can get alpha-chloro or alpha-bromo carboxylic acid. But can we make alpha-iodocarboxylic acid with the help of HVZ reaction? I could not find any reference of HVZ ...
5
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0answers
1k views

Mechanism of reaction between substituted aniline and potassium thiocyanate in presence of bromine and glacial acetic acid

Im currently doing this project where in we are synthesizing 2-amino-6-substituted benzothiazole by using p-substituted aniline with potassium thiocyanate in presence of bromine and glacial acetic ...
5
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0answers
392 views

What is the degradation mechanism of pyrrole?

A vial of pyrrole (that was occasionally exposed to air) changed its color while degrading from pale yellow to dark orange. What is the mechanism of pyrrole degradation? What are the resulting ...
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709 views

How does the Kucherov reaction work if the alkyne is aromatic?

I know how the Kucherov reaction works for aliphatic alkynes, but what if the alkyne has a phenyl attached? How will the aromatic ring affect the reaction of alkynes with water?
5
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1answer
2k views

Relationship between auto-ignition temperature with pressure and fuel

Experimentally it appears that increase in pressure, fuel concentration, and chain length causes AIT to decrease until a minimum where even further increase in these parameters increases the AIT. ...
5
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1answer
2k views

Orientation in benzene rings with more than one substituent

Why is it that the chlorination of 1-chloro-3-nitrobenzene (18) gives 1,4-dichloro-2-nitrobenzene (19) as the major product, 1,2-dichloro-3-nitrobenzene (20) as a minor product and 1,2-dichloro-4-...
5
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1answer
790 views

Bromination of alkenes

In regard to the mechanism of halogen addition, consider the situation when we add a halogen (say, bromine) to an unsymmetrical alkene about the double bond (say, propene) in the presence of $\ce{CCl4}...
5
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1answer
2k views

Protonation of Carbonyl oxygen in Fischer Esterification

In the Fischer Esterification, why is it the acid's carbonyl oxygen getting protonated and not the hydroxyl oxygen? This protonation occurs in Step 1 of the mechanism below. I read in some textbooks ...
4
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0answers
245 views

Mechanism of DPD (N,N-diethyl-p-phenylenediamine) reaction with free chlorine

NOTE: As I've been finding new informations about the question, I've been editing the question to keep it up to date. If some comment doesn't make sense just check the Edit History. DPD (N,N-diethyl-...
4
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0answers
56 views

An unconventional decarboxylation to form bullatenone

I recently had an assessment which required me to draw the mechanism of decarboxylation of a $\beta$-ketoacid. However, it is slightly peculiar because there is the presence of $\alpha$, $\beta$-...
4
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0answers
119 views

Mechanisms of Birch and Bouveault-Blanc Reductions

The question is all about the sequence of a possible Birch- and Bouvault-Blanc-Reduction in this exemplary substrate. With which reduction the mechanism begin? My first attempt was to classify the ...
4
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0answers
45 views

Meaning of electrochemical vs nonelectrochemical steps

Can someone please explain to me what is meant by an electrochemical reaction step and how it differs from a nonelectrochemical reaction step in the same overall reaction in the context of ...
4
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0answers
206 views

Reaction of alpha hydroxyketone with KOH

What happens when 2-hydroxycyclohexan-1-one (an alpha hydroxyketone) reacts with aqueous $\ce{KOH}$? I tried something like Favorskii rearrangement, but it's wrong because OH isn't a good enough ...
4
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0answers
247 views

Mechanism for reaction of enol ether with HBr

Please refer to the image for the question. I tried two different mechanisms for the reaction (1 and 2) and ended up with two different products. Now I can't decide which of the two mechanisms would ...
4
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0answers
332 views

Textbook suggests secondary alkyl halides do not undergo SN1 reaction

The 8th edition of Organic Chemistry by Paula Bruice suggests that secondary alkyl halides do not undergo SN2 reactions. However, many other sources state the opposite. So, what is the correct answer? ...
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0answers
2k views

Reaction mechanism for reduction of alkyl halide to alkane

Alkyl halides are reduced by zinc and dil. $\ce{HCl}$ into alkanes $$\ce{ CH3Cl + H2 ->[Zn][dil\text{.} HCl]CH4 + HCl}$$ What I don't understand is the underlying mechanism behind this ...
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0answers
85 views

Rationalise the Relative Reactivity of Borane and DIBAL as Reductants

In Clayden's Organic Chemistry (Second Edition) it is written that borane is useful in chemoselectively reducing the most nucleophilic carbonyl to its corresponding alcohol. It is later said that ...
4
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1answer
1k views

Reaction of amines with diethyl oxalate (Hofmann Separation Method)

Why does only one molecule of secondary amine react with diethyl oxalate and two molecules of primary amine react with diethyl oxalate? I feel secondary amine also should have reacted similar to ...
4
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0answers
146 views

Why is this step exothermic?

From Wade's "Organic Chemistry" [1, p. 1003-1004]: MECHANISM 21-7 Conversion of an Ester to an Amide (Ammonolysis of an Ester) Step 2, loss of a poor leaving group is justified by claiming ...
4
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0answers
148 views

Reaction of bicyclic diol with periodic acid

I'm in an organic 1 class, and we learned about using periodic acid (HIO4) to cleave a glycol into two carbonyl groups, oxidizing the glycol. However, in the given reaction (see picture below), I'm ...
4
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0answers
328 views

Number of intermediates and transition states in hydration of given alkene

What is the number of transition states and intermediates formed in the following reaction? My thought: First the alkene extracts $\ce {H^+}$ from the acid to form a carbocation. This step ...
4
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0answers
398 views

Friedel–Crafts alkylation of benzene with propyl chloride

This is a question from my textbook: Why does the alkylation of benzene with 1-chloropropane give (propan-2-yl)benzene and not (propan-1-yl)benzene? The book shows the reaction with chloromethane ...
4
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0answers
75 views

What happens when I divide two molar flow rates in a chemical equation?

I don't quite know how summarize my question in the title. I have a combustion process given by this equation: $$\ce{C10H22 + 15.5 O2 + 58.25 N2 -> 11 H2O + 10 CO2 + 58.25 N2}$$ This process ...