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.

Filter by
Sorted by
Tagged with
2
votes
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 ...
1
vote
1answer
1k views

Chemical software for solving reactions [closed]

I'm looking for a software which can solve chemical equations. For example something like this (given with result): \begin{align} \ce{CH4 + 2O2 & → CO2 + 2H2O} \\ \ce{C3H6 + HCl & → ...
1
vote
2answers
4k views

Alllylic bromination of 1-butene

My book asks me to consider reacting 1-butene with NBS and light. I know that NBS and light leads to radical formation, and this is an allylic/benzylic bromination problem. However, my book only ...
0
votes
1answer
737 views

Why does a hydride shift take place in the cannizzaro reaction?

Hydride is a poor leaving group so a hydride shift should not take place and instead the attacking hydroxyl should leave the carbonyl group. I don’t understand why this doesn’t happen?
0
votes
1answer
1k views

Computing the concentration of a reactant given formation of products

At high temperatures nitrogen dioxide decomposes into nitrogen oxide and oxygen gas according to $$\ce{2 NO_2 -> 2 NO + O_2}$$ I have a question now. Let's say at a certain temperature I'm given ...
-2
votes
1answer
91 views

Rearrangement of 8a-ethyl-1,3,4,8a-tetrahydronaphthalen-4a(2H)-ol [closed]

really sorry for that previous post. I was actually half-asleep when I posted that q, hence the q was unclear. I am again reposting that question The answer is given as A. Can anyone please explain ...
-2
votes
1answer
6k views

SN1 like reaction acid-cataylzed hydrolysis of epoxide [closed]

What would be the reaction mechanism for the reaction between epoxide and $\ce{H2SO4}$?
63
votes
4answers
17k views

How does Walter White make pure crystal meth using a non-stereospecific reaction?

In the fantastic TV series Breaking Bad, Walter White, the dying chemistry teacher, takes to making crystal meth (d-methamphetamine) by several routes. Initially, he uses the common small-scale route ...
16
votes
1answer
36k views

Why concentrated sulfuric acid for dehydration and dilute for hydration?

To dehydrate ethanol one uses concentrated sulfuric acid: $$\ce{C2H5OH ->[\text{conc.} H2SO4] C2H4 + H2O}$$ but to go in the reverse direction, dilute sulfuric acid is used: $$\ce{C2H4 + H2O -&...
13
votes
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...
29
votes
1answer
533 views

How does Palladium dissociate H₂ so easily?

If I understand correctly, $\ce{H2}$ in the presence of $\ce{Pd}$ readily dissociates as it dissolves into the metal. With the dissociation energy for the $\ce{H—H}$ bond being so large, how is this ...
12
votes
3answers
5k views

Comparing SN2 reaction rates

I've read in a book that the main factor for determining SN2 reaction rate is steric hindrance. The lesser it is, the faster the reaction. So consider this question: $\ce{KI}$ in acetone undergoes ...
32
votes
1answer
807 views

Why does hyperconjugation help for ring cleavage?

The question was to rationalize it the ring cleavage happens concerted or non-concerted. The papers "The Mechanism of the Thermal Decomposition of 1-Pyrazolines and Its Relationship to ...
25
votes
2answers
348 views

Why does a mixture of siloxene and cerium(IV) sulfate luminesce?

I performed an experiment where siloxene and cerium(IV) sulphate were mixed together: when I did so the mixture produced an orange-yellow glow. Why does it glow? What is it about the two chemicals in ...
10
votes
1answer
3k views

How does the HCl-KCl Buffer work?

I have just been studying the $\ce{HCl}$-$\ce{KCl}$ 'buffer', but there are still quite a few things I am uncertain about. I would appreciate any help in clearing up some questions I have. What I ...
10
votes
1answer
4k views

What is the directive influence of the tert-butyl group in electrophilic aromatic substitution?

We know that hydrocarbon side-chains on a benzene ring influence electrophilic substitutions by directing the incoming electrophile to attack at ortho and para positions. The following ...
14
votes
2answers
10k views

Reduction of glucose to hexane with hydroiodic acid

My book (NCERT India) states that n-hexane is formed when glucose is heated in the presence of hydrogen iodide. That is, the following reaction takes place: $$\ce{C6H12O6 + HI ->[{\Delta}] C6H14}$$ ...
10
votes
1answer
169 views

Is isobutyl chloride or ethyl chloride more reactive in an SN1 reaction?

Compare the rate of $\mathrm{S_N1}$ reaction in the following compounds: We see that both compounds form primary carbocations. However, there is more hyperconjugation in the second compound as ...
4
votes
2answers
552 views

α,β-unsaturated carbonyl compounds and alkyl addition

In my book it is suggested that in order to add alkyl groups in α,β-unsaturated carbonyl compounds we use organometallic reagents such as organolithium reagents. In the previous chapters it was ...
22
votes
2answers
10k views

The acidity of boric acid

The “real way” boric acid behaves as an acid in water is first by acting as a Lewis acid (bottom reaction, in black). In fairness to the undergrads, I’d bet >25% of graduate students around the ...
17
votes
2answers
839 views

Mechanism of a dephenylation reaction

I recently came across this reaction in my undergraduate labs. The experiment is taken from this article: J. Chem. Educ., 2008, 85, 413. The condensation of 2-methoxynaphthalene with cinnamoyl ...
12
votes
2answers
56k views

Nitrobenzene reduction with (tin) Sn catalyst: Why is C-H bond cleavage preferred over O-H bond cleavage?

I am trying to understand this mechanism for nitrobenzene reduction with $\ce{Sn/HCl}$. I do not understand why it implies that you pull off the $\ce{C-H}$ hydrogen instead of the $\ce{O-H}$ hydrogen ...
11
votes
4answers
2k views

Does radioactivity affect chemical reactions?

Do compounds of radioactive elements show a different behaviour? What happens when the radioactive part of the given compound decays? e.g. Radium chloride; what happens to it when radium decays?
11
votes
1answer
1k views

Resonance in carbocation derived from allenes

During a reaction if addition on one of the $\pi$ bonds of an allene (containing even number of $\pi$ bonds like $\ce {H2C=C=CH2}$) takes place then a carbocation is formed. To decide the position of ...
11
votes
1answer
2k views

Purpose of ammine in Tollens' reagent

In this previous question the mechanism for the reaction of Tollens' reagent was outlined. As I understand it the oxidising agent in Tollens' is the diamminesilver(I) complex $\ce{[Ag(NH3)2]+}$ but ...
11
votes
3answers
39k views

Gattermann-Koch Reaction with Phenol Substrates

The Gattermann-Koch Reaction involves the formation of an aryl aldehyde using carbon monoxide and hydrochloric acid as reactants. The reaction is catalyzed by aluminium trichloride in the presence of ...
9
votes
3answers
7k views

Why do we use ethanol in SN2 reaction?

Solomons and Fryhle has an example in which they have showed a very simple substitution reaction. The question was to synthesize methyl iodide. What they have done is taken methyl chloride and ...
8
votes
0answers
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 ...
6
votes
1answer
1k views

Rate and order confusion

I just learned about rate and order... I just want to confirm if these three ideas are correct: If the first elementary step is the slow step, will the stoichiometric coefficients of the reactants in ...
5
votes
1answer
4k views

Why is the addition of a singlet carbene to an alkene stereospecific?

Why is the addition of a singlet carbene to an alkene stereospecific, but not when a triplet carbene is added?
5
votes
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
votes
1answer
4k views

Ring contraction in pinacol rearrangement of cyclohexane-1,2-diol

I came across this question in three different textbooks. The question was: What is the major product obtained on dehydration (treatment with concentrated $\ce{H2SO4}$) of cyclohexane-1,2-diol. I ...
4
votes
1answer
2k views

Birch Reduction Of Anthracene

Which ring of anthracene is reduced during Birch Reduction? What will the final product look like? Why? My teacher said that the more electron deficient ring should undergo the reduction but I ...
2
votes
1answer
18k views

How does sodium in ethanol reduce carbonyl compounds?

According to my teacher, Na in ethanol reduces carbonyl compounds (e.g. aldehydes and ketones) to alcohols. However, I can't see where the hydrogen needed for reduction comes from. How does the ...
20
votes
3answers
6k views

Why do SN2 reactions of alkyl halides proceed differently with KCN and AgCN?

Alkyl halides react with $\ce{KCN}$ to form alkyl cyanides as the main product, whereas the use of $\ce{AgCN}$ leads to isocyanides as the chief product. Why does this happen?
18
votes
1answer
599 views

What is the chemistry behind this “petrol from air” technology?

A recent news report in the UK claimed a breakthrough in making a petrol equivalent from carbon dioxide and water: A small British company has produced the first "petrol from air" using a ...
18
votes
1answer
3k views

Why does depurination happen at a higher pH (or under less harsh conditions) than depyrimidation?

I've always wondered why the N-glycosidic bond, which connects the adenine or guanine purine bases to their sugars, was the easiest to cleave via acid hydrolysis, or why purines have the lowest ...
17
votes
4answers
4k views

How does sulfuric acid dehydrate sugars?

I know sugars have $\ce{-OH}$ groups, and that sulfuric acid is a strong acid. What I'm failing to see is how exactly sulfuric acid dehydrates sugars. Does it protonate the hydroxyl groups, making ...
17
votes
1answer
2k views

Fehling's test arrow pushing mechanism

I am currently attempting to generate an arrow pushing mechanism for the oxidation of glucose to gluconic acid using Fehling's solution. My original thought was to go the route of alcohol oxidation ...
14
votes
1answer
2k views

Mechanism for basic hydrolysis of α-chloronitrile to ketone?

In Corey's 1969 prostaglandin synthesis,1 compound 2 is formed from compound 1 by: [...] treatment with 2.5 equiv of potassium hydroxide (added as a hot saturated aqueous solution) in dimethyl ...
11
votes
1answer
2k views

In the elementary steps of a reaction, why do we assume that the coefficients of a reactant correspond to its order?

Recently, I was taught that the coefficients of the reactants in an elementary step of a reaction indicates that reactant's order. Why is this the case? I thought that the order of a reactant was not ...
10
votes
1answer
2k views

What is the oxidation mechanism of gunpowder?

I've been recently looking into fireworks and the chemistry of explosives, and I found out that, amongst others, one of the most important reactions in gunpowder ignition is the oxidation of charcoal ...
9
votes
1answer
550 views

Why does trihaloacetaldehyde formed during the haloform reaction not undergo a Cannizzaro reaction?

We know trihaloacetaldehyde is formed during the haloform reaction of acetaldehyde with a halogen in strong base. Since it has no alpha hydrogens, I expected that it might undergo a Cannizzaro ...
9
votes
2answers
631 views

How does an oscillating reaction work?

I watched a video showing an orange solution that goes to clear and then back to orange (and so forth.) The reaction goes through a number of cycles before it will no longer oscillate. This tells me ...
8
votes
1answer
18k views

Reaction mechanism for reduction of nitrobenzene to aniline in catalytic and acidic media

Can anyone explain the reaction mechanism of the two reactions given below? They are the conversion of nitrobenzene to aniline in catalytic ($\ce{H2/Pd}$ in ethanol) and acidic ($\ce{Sn/HCl}$ or $\ce{...
8
votes
1answer
7k views

Reduction of acids with borane

What is the mechanism of the reduction of organic acids with borane? Borane reductions don't work well with electron deficient carbonyl groups. Why is that so, and how isn't the carboxyl group an ...
7
votes
1answer
361 views

Periodically oscillating chemical reactions?

I've seen before chemistry demonstrations where solutions are mixed with one another and subsequently where the resulting product goes through periodic color changes: for example blue to orange and ...
7
votes
1answer
806 views

What is the chemical basis for superglues?

There are a variety of different types of glues, some derived from animal or natural materials and some designed by chemists. Some glues need to be activated before they harden and stick (many epoxies,...
7
votes
2answers
16k views

Exothermic or Endothermic reactions

Can we determine whether a reaction is endothermic or exothermic? For example if we are given the following reactions: $$\ce{2SO2 + O2 -> 2SO3}$$ $$\ce{H2 + I2 ->2HI}$$ $$\ce{N2 + 3H2 -> ...
7
votes
1answer
551 views

What is the reaction mechanism of nitrogen leaving from diazo compounds?

When a diazo compound is formed, and then a nucleophile is added to the mixture. Will nitrogen gas leave first or will the nucleophile have to "do" a substitution reaction? What I mean is will the ...