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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.

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700 views

Neighbouring group participation with and without retention of configuration in nucleophilic substitution of 2,6-dichloro-9-thiabicyclo[3.3.1]nonane

Treatment of the dichloride A under the conditions indicated gives B with retention of configuration, while treatment of dichloride C gives D with inversion of configuration. I am having ...
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199 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 ...
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18k views

Reaction of phenol with Zinc dust

I have seen this reaction many times: $\text {Phenol}+\text{Zn}\ce {->}\text{Benzene}+\text{ZnO} $ But what is the mechanism?! Tried a lot but couldn't cook up one... Thanks for any help...
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1k 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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152 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 ...
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650 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 ...
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606 views

Birch reduction of anisole

Hepworth, Waring and Waring (2002) mentions that: In general, electron-withdrawing substituents make the arene more susceptible to reduction, while the opposite applies for electron-donating ...
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143 views

Why would a reaction favor one isotope over another?

In my instrumentation class last semester, we were asked to read a short paper. The paper described a technique for determining whether dinosaurs were cold-blooded or warm-blooded based on the amount ...
8
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252 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 ...
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1k views

Product of Friedel-Crafts cyclisation of (3-methylpent-4-en-1-yl)benzene

My proposed mechanism and final product is: But the book says the answer is: I know that a 6 membered ring is more stable than a 5 membered ring so I made the product with the 6 membered ring (...
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589 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. ...
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75 views

Compare rate of hydrohalogenation between 1,2-diphenylethene and 1-phenylpropene

Consider the compounds, (I) - 1,2-diphenylethene and (II) - 1-phenylpropene. Compare their rate of hydrohalogenation (HX addition) I feel that the answer should be (II) > (I), but to my surprise it's ...
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164 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 ...
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611 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 ...
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360 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 ...
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633 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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257 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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174 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 ...
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352 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 ...
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166 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 ...
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152 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 ...
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118 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 ...
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2k 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 ...
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89 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 ...
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106 views

On the mechanism of the nitrogen-removal step of the Wharton olefin synthesis

In today’s reaction seminar, the Wharton transposition made an appearance. In our practice case it started from the epoxide as in scheme 1 below as on Wikipedia; Kürti/Csakó (page 482) begin from the ...
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298 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 ...
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74 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 ...
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81 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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241 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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71 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 ...
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92 views

Side chain formation in polymerisation of ethylene

I am having difficulty understanding (or at least need confirmation of my understanding) of this diagram regarding the formation of sidechains of polyethylene. If someone could explain it, that would ...
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109 views

Benzyl (3,4-difluorophenyl)carbamate reaction with epoxide in basic conditions

I attempted this mechanism, however I am uncertain if I am correct.
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579 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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903 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 ...
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342 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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623 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?
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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. ...
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51 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 ...
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39 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 ...
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140 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 ...
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146 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 ...
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218 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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66 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 ...
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101 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 ...
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113 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 ...
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216 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 ...
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57 views

What is the mechanism of hydroperoxide reduction by bisulfite?

I am using bisulfite to quench allylic hydroperoxide products from a singlet oxygen ene reaction, to the corresponding alcohols. What is known about the mechanism of this reaction, and in particular ...
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93 views

Expedient phosponium synthesis (for Wittig)

I have been making ethyltriphenylphosphonium bromide (somewhat of a time crunch, would have used iodoethane instead of bromoethane if we didn't have to wait for it). All the syntheses I see of Wittig ...
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0answers
932 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.
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125 views

[3+1]-Cycloadditions of Sulfur Ylides and 1,3-Dipoles(?)

My question is basically regarding the stereoselectivity of the situation. I am not being able to decide on the positioning of the sulfur ylide with proper justification. In the attached hand-drawn ...