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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4
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2answers
195 views

Mechanism of ring formation of an epoxide under acidic aqueous conditions

I am trying to figure out the mechanism of this reaction: I think the $\ce{H+}$ will first attack the oxygen of the epoxide and another $\ce{OH-}$ will be added to the most substituted carbocation, ...
9
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1answer
244 views

Mechanism of the formation of peracetic acid

Wikipedia says that the equilibrium $$\ce{H2O2 + CH3COOH ⇌ CH3COOOH + H2O}$$ occurs. What is its mechanism? The following is my speculation. The first possibility is that $\ce{CH3COOH}$ is ...
3
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1answer
160 views

How do I decide whether ring will expand in this reaction or not?

Attempt: After forming the carbocation adjacent to the cyclopropyl ring I had two options, $\ce{Cl-}$ then and there without any changes Expand ring, form a new carbocation and add $\ce{Cl-}$ ...
3
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1answer
141 views

Which is easier, the nitration of toluene or the nitration of mesitylene (1,3,5-trimethylbenzene)?

Does the toluene can undergo nitration easier than mesitylene (1,3,5-trimethylbenzene), due to the high repulsion that will occur between $\ce{NO2}$ and the two adjacent methyl groups (in mesitylene ...
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1answer
46 views

2-step reaction mechanism for the decomposition of NO2Br

I need to propose a 2-step reaction mechanism for the following reaction: $$\ce{2NO2Br -> 2NO2 +Br}$$ And prove the mechanism is consistent with: $$v=k[\ce{NO2Br}]^2$$ For the mechanism to be ...
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1answer
8k views

Chlorination of propene at 773 K

The first step of preparation of glycerol with propene involves the chlorination of of propene at 773 K. It results to form allyl chloride. However the halogenation of alkenes generally give vicinal ...
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1answer
94 views

Mechanism of oxidative dearomatisation with hypervalent iodine

The following step was taken from the synthesis of Kinamycin C on SynArchive. It employs the use of a peculiar reagent, that is, bis(acetoxy)iodobenzene (BAIB), also known as phenyliodine(III) ...
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0answers
148 views

Mechanism for Friedel-Crafts Acylation in Synthesis of Sertraline

In the first step of the synthesis of Sertraline, aluminium chloride catalyst was used in a Friedel-Craft's reaction to give the following product. My question is how does the exact mechanism work? 1-...
3
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1answer
983 views

Tert-butoxide in SN2 reactions

Can Tert-butoxide displace bromide via SN2 reaction? I read that Tert-butoxide is bulky and has steric hindrance, even with primary substrates. How is this reaction (picture below) possible? Source: ...
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1answer
36 views

Do all reactants have appear in the first mechanism of the rate law?

I have the following reaction, $$\ce{CO + NO2 -> CO2 +NO}$$ The "second" mechanism is given: $$\ce{NO3 + CO -> NO2 + CO2}$$ So when searching for the first mechanism, I found this one to work: ...
12
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1answer
525 views

What are the key chemical characteristics that determine the octane rating of fuel?

The octane rating of petrol (gasoline) is a measure of the how much compression a fuel air mixture can have before detonating (which in petrol engines is a bad thing as you want the mix to combust ...
3
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1answer
222 views

LDA and an aldehyde

Compounds A and B both react with LDA (lithium diisopropylamide, a strong base) to form the same anion C with the formula $\ce{C4H5O^-Li^+}$. I am unfamiliar with LDA. My first thought was that ...
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1answer
66 views

Why do metals form cations?

metals that have a low number of occupied shells such as lithium and potassium should have a stronger electrostatic attraction to their nuclei, so what causes them to always lose their electrons ...
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0answers
41 views

How is a ring formed when a carbon atom in an aliphatic chain attached to benzene ring has a positive charge?

This is my approach towards this problem. First off, a positive charge would appear in the C atom at the end of the chain, and then that carbocation would rearrange into a tertiary carbocation. But I ...
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1answer
61 views

What happens in this reaction! Some hints needed

I understand step A involves reductive ozonolysis. and that step B is addition involves addition of ammonia to the carbonyl site to form imines. But what does the sodium salt of trichloroacetic acid ...
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1answer
1k views

What is the correct product of the Diels-Alder reaction between 2-ethoxybuta-1,3-diene and (Z)-acrylaldehyde-3-d?

What is the correct product of the Diels-Alder reaction between 2-ethoxybuta-1,3-diene and (Z)-acrylaldehyde-3-d? It keeps mentioning that my regio-selectivity is incorrect. And that I should ...
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1answer
60 views

Why doesn't open-chain glucose react with water readily in aqueous solution?

Though the exact number given varies from 0.02% to 3%, it's well agreed that glucose spends a very small percentage of its time in aqueous solution as a linear aldehyde. Glucose's overwhelming ...
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0answers
44 views

What constitutes something being designated as big, bulky in terms of SN2 vs E2

When deciding between $\mathrm{S_N2}$ and $\mathrm{E2}$ for primary and secondary alkyl halides, is there a particular method or molecular size or any other threshold, which allows us to designate ...
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2answers
32 views

Negative charges in acid-catalyzed reactions [closed]

Whenever my professor draws a mechanism in an acid-catalyzed reaction, he always says you can't form negative charges. Why is that?
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2answers
68 views

What happens when mixing elemental mercury with sodium hypochlorite solution [closed]

Say you spilled elemental mercury from a thermometer and used household bleach on it, what would be the reaction if any?
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59 views

Converting hydrogen to methane

I am in need of small amount of pure methane for laboratory purpose. I have hydrogen generator in the lab. Is there a possibility of generating methane from hydrogen ? May be make hydrogen flow ...
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1answer
91 views

Hydrate decomposition equation steps

When a hydrate decomposes it loses water molecules in steps. Does each step have a chemical equation? If so is the following equations for decomposition of cupric sulfate hydrate correct? $$ \begin{...
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55 views

method to certify the number of chiral carbons in fischer and haworth projection of glucose

While reading some notes about Glucose and its various projections: Fischer Projection: 4 chiral centres Haworth Projection: 5 chiral centres My doubt is that is there any (specific) method (...
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1answer
34 views

Aldehyde and ketone reactions

Reagents to carry out above conversion, P, Q, R respectively are: (a) $\ce{H2C=CH-CH2-Br}$, $(\ce{HO-})$, $[\ce{HO-}, Δ]$, Wacker process. (b) $\ce{H2C=CH-CH2-Br(HO^-)}$, Wacker process, $\...
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1answer
472 views

The major product of the following reaction

Here,1,2-dibromobutane is reacted with i) alc. $\ce{KOH}$ ii) $\ce{NaNH2}$ in liq. $\ce{NH3}$ According to me, since alc. $\ce{KOH}$ causes dehydrohalogenation, using Saytzeff's rule the product ...
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1answer
41 views

What is the minimum operating temperature of chemical hand warmers?

I have been looking at chemical hand warmers such as Hot Hands, Grabber and HotSnapZ. Unfortunately, I cannot find a minimum operating temperature for these types of devices. Logic tells us that they ...
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2answers
6k views

Do alcohols react with alkyl halides?

I wonder if alkyl halides react with alcohols or not. I searched on Google but could only find reaction of alcohols with hydrogen halides
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1answer
258 views

What is the mechanism of azulene synthesis?

In the Organic Syntheses preparation of azulene (http://www.orgsyn.org/demo.aspx?prep=CV7P0015) there are two reactions. First is a clevage of the C-N bond in pyridine and the second one is the ...
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21 views

Kinetics for E1cb reactions

We were taught that the kinetics of a reaction is determined by the reactions ‘rate determining step’ which is also the slowest step of the reaction. For E1 as well as E2 reactions the slowest steps ...
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1answer
48 views

What do electrons usually do when lead acid battery is idle?

Lead acid batteries operation are governed by Redox reactions for charging and discharging. But, what do electrons usually do when lead acid battery is idle? And why? Assumptions: Say more ...
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2answers
2k views

Mechanism for ring contraction from 2-methylenecyclobutanol to 1-methylcyclopropanecarbaldehyde

I am stuck between two paths. I was going to protonate the alcohol to give a better leaving group, leaving a 2 degree carbocation and then go on with a hydride shift. But, I'm not sure what that may ...
4
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2answers
450 views

Finding all Chemical Reactions Given Products and Reactants

Suppose only a set of chemical formulas is given. How can you find all mathematically possible chemical equations whose educts and products are only from this set? Take e.g. the set $\{ \ce{C, H2, O2,...
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1answer
513 views

Active methylene group nucleophilic substitution

The first product formed after reaction with $\ce{^-CH(COOEt)2}$ followed by hydrolysis is [2-(naphthalen-1-yl)ethyl]propanedioic acid: But is the reaction $\mathrm{S_N1}$ or $\mathrm{S_N2}$? On ...
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1answer
32 views

Influence of protic and aprotic solvents on SN reactions [closed]

How does protic and aprotic solvents influence reaction mechanism considering SN1 vs SN2?
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1answer
142 views

How is energy released when a chemical bond is formed? [closed]

Chemical reactions are classed as endothermic or exothermic. Defn: exothermic (of a reaction or process) accompanied by the release of heat. The heat is released when the chemical bonds in the ...
13
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1answer
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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3answers
52 views

Effect of concentration on rate of reaction

I came across this problem: The $\ce{2NO + Br2 -> 2NOBr}$ follows the mechanism below: $$ \begin{align} \ce{NO + Br2 &-> NOBr2} & &\text{fast} \tag{1} \\ \ce{NO + NOBr2 &-...
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0answers
47 views

Will hydrogen chloride dissolved in ethanol react with magnesium?

Magnesium will react with aqueous HCl to form magnesium chloride and hydrogen gas. Simple. But I've just read in my textbook that HCl in a solution of ethanol no reaction will take place. There is no ...
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1answer
92 views

Confusion about the Sn1 and Sn2 Mechanism

My book says, and I understand, that the Sn1 mechanism is much faster for tertiary alkyl halides than primary. And the opposite for Sn2. This all makes sense. What I don't get is the conclusion it ...
3
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1answer
165 views

Gibbs free energy of formation vs. Gibbs free energy of reaction?

Consider the following reaction: $$\ce{A(s) + B(s) <=> AB(s)}.$$ I know there might be kinetic limitations but I am only interested in thermodynamic relations. In general, the Gibbs free ...
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0answers
67 views

Victor Mayer test for 2° alcohol

In the last step in Victor Mayer test for 2° alcohol, why do we need to add an alkali like NaOH? Isn't pseudo nitrolic acid that is formed already blue in colour? What would be the reaction of alkali ...
1
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1answer
501 views

Nucleophilic attack on cyclic intermediates in dibromination and oxymercuration reactions of alkenes

Why does the nucleophile attack the most substituted carbon after the formation of a cyclic intermediate (three membered ring) in the cases of halogenation and oxymercuration of alkenes, as if there ...
2
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0answers
118 views

Kinetic and thermodynamic control of sulphonation of toluene

Sulfonation of toluene with conc. $\ce{H2SO4}$ at room temperature gives ortho- and para-toluenesulphonic acid (with $95 \%$ yield), whereas sulfonation of toluene with conc. $\ce{H2SO4}$ at $\pu{150-...
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0answers
33 views

Naive question on the SN1 mechanism

I was teaching the $S_N1$ mechanism to a friend. He asked a question a subtle question I can't shake off. Take a tertiary alkyl halide and aqueous sodium hydroxide. The first step is the formation of ...
19
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3answers
5k views

Which compound reacts faster in the Cannizzaro Reaction?

Which reacts faster in the Cannizzaro Reaction? a) $\ce{OHC-C6H4-NO2}$ b) $\ce{OHC-C6H4-OCH3}$ Obviously, a better hydride releasing group will react faster. Therefore my answer was b, as $\ce{-...
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3answers
4k views

How is it that the equilibrium constant does not depend on the mechanism?

For a reaction of the form $$\ce{aA + bB <=> cC + dD}$$ the equilibrium constant is $$K_c=\frac{[\ce{C}]^c[\ce{D}]^d}{[\ce{A}]^a[\ce{B}]^b}$$ regardless of the mechanism of the reaction. ...
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0answers
39 views

Equilibrium Constant and Reaction Mechanism [duplicate]

How is it possible for the equilibrium constant to not depend on a reaction's mechanism? For the elementary reaction $$aA + bB \rightleftharpoons dD + eE$$ I understand that the rate of the ...
9
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2answers
149 views

Which chemical reactions don't involve bond breaking?

I recently came across a question in which an option is 'Breaking a chemical bond is the first step in any chemical reaction', which lead me to think of reactions which do not involve bond breaking. ...
2
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1answer
34 views

Pseudoelementary reactions in the Briggs-Rauscher oscillatory reaction mechanism

In this paper on the Briggs-Rauscher mechanism (JACS, 1982, paywalled), Noyes and Furrow propose an explanation of the oscillatory behaviour of the reaction based off of about eleven reactions from a ...
2
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1answer
2k views

Converting cyclic compounds to linear compounds (possible ?)

Can one convert from cyclic convert to linear compound? Like $Cyclohexane$ $+$ $?=Hexane$ Even in High Temp and Pressure? I know it is very tough since we are going from a stable compound to a ...