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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.

372 questions with no upvoted or accepted answers
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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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88 views

Can aldol reaction occur during α-halogenation of ketone?

I know both aldol and $\alpha$-halogenation reaction well. I know that in and aldol reaction, the carbonyl containing molecules like ketones and aldehydes attacks themselves when base like $\ce{OH-}$...
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437 views

What are the products A and B in the following reaction?

What are the products A and B in the following reaction? According to me, the $\ce{NH2^-}$ anion being a strong base would form an alkoxide ion. But since there are 3 $\ce{OH}$ groups it will ...
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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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2k views

How does Lindlar's catalyst work?

I can not find a mechanism online. I understand that some poisoning effect causes the catalyst to be unable to reduce an alkene to alkane; however, if the catalyst is poisoned, how does it continue to ...
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210 views

Is the following rate law possible for the given reaction?

A researcher is investigating the following overall reaction: $$\ce{2C + D -> E}$$ The researcher claims the rate law for the reaction is written as follows: $\text{Rate} = k[\ce{C}][\ce{...
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684 views

Iodine/ Magnesium Exchange reaction?

Traditional Grignard reagents are made by reacting alkyl halide with Magnesium metal. However, the preparation and scope of their application have been limited because of low functional group ...
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65 views

Questions about Genetic algorithm paper of Gilman and Ross

I want to reproduce an (old) biochemistry paper of Gilman and Ross, i.e. " Genetic algorithm selecetion of a regulatory structure that directs flux in a simple metabolic model." ( The following link ...
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8k views

Why do NaNO3 + Al + NaOH yield ammonia?

From Russian test problem 4301: $$\ce{3NaNO3 + 8Al + 5NaOH + 18H2O -> 8Na[Al(OH)4] + 3NH3(g)}$$ How does ammonia evolve here? Is it that we get hydrogen gas evolving in the reaction between Al ...
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1k views

Gilman Reagent with vinyl chloride

What are the products formed when vinyl chloride reacts with dimethyl copper? I thought the product formed would be propene. But answer given is PolyVinylChloride. How does polymerization take place?
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What reactions does this steel cold-bluing solution undergo?

Bluing steel generally refers to the process of forming a protective layer of $\ce{Fe_3O_4}$ ("black iron oxide") that prevents normal rust from forming. The chemistry behind the traditional ...
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3k views

How is the reaction between Aluminium and Mercury Chloride possible?

Aluminium is coated with a thin layer of Aluminium Oxide. Why then do we write the reaction as $$\ce{2Al + 3HgCl2 → 2AlCl3 + 3Hg}$$ Shouldn't we first write an equation showing how $\ce{HgCl2}$ ...
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417 views

Corey-Seebach reaction regioselectivity

Does Corey-Seebach reaction with conjugated enones undergo in a direct or conjugated fashion? Can the two sulfur atoms soften the carbanion enough for it to undergo conjugated addition? If not, would ...
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972 views

Does the addition of chlorine to carbon-carbon double bonds proceed through a halonium ion?

I need some serious help with the mechanism of ionic addition, both my textbook and my teacher are at odds with internet videos (khan academy) which both seem to be at odds with quote, "recent ...
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886 views

Mechanism of dehydration of alcohols by iodine/triphenylphosphine

This paper describes the dehydration of an alcohol to form an alkene. What is the mechanism of alcohol dehydration with iodine? Why can only iodine of all the halogens be used?
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866 views

Nucleophilic attack by bromine?

According this scheme the bromine act as a nucleophile and attacks pyrimidinium generating Br+ species? I always thought that Br2 acts solely as electrophile with Br- as by product.
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125 views

Iron (II) dioxygen reaction mechanism?

Ok so I'm confused about the mechanism for this process: Now the idea here is that iron first becomes oxidised to Fe(III) by placing an electron in the antibonding orbital of dioxygen. This is ...
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407 views

What prevents self-condensation in the Perkin reaction?

An acid anhydride is condensed with an aromatic aldehyde in the Perkin reaction. The latter is non-enolisable, and thus the former forms the enolate which attacks as a nucleophile. If the attack is ...
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82 views

Grignard reaction - exchange of groups

Why is this reaction successful: Why doesn't metal-halide exchange occur easily to get Ar-MgCl and R-Br?
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63 views

Can one dichlorotriazine molecule form two bonds with cellulose?

In all the reactions I saw online, dichlorotriazine is shown to form only one bond with cellulose (example 1, example 2; paper). But cellulose has many potential sites for bonding. Can ...
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458 views

Why does the OAc group leave in the first step of Oxymercuration?

The above picture shows the first step of Oxymercuration. The electrons attack the Mercury atom but the OAc group leaves. Why is this? Hg is a transition metal with a number of available oxidation ...
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740 views

Are multiple transition states possible? Criteria to choose the correct one?

I am studying a reaction using electronic structure methods using various software packages (ORCA,GAMESS, G09) and have found two possible transition structures between product and reactant. Both have ...
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1answer
445 views

Preparing an amine from an azide

Is there any mechanism available for reduction of alkyl azides to amines. One of the reactions is conversion by $\ce{Na}$ in ethanol or by $\ce{LiAlH4}$. But how do these proceed? $\ce{LiAlH4}$ will ...
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1answer
87 views

Regioselectivity in Diels Alder reaction

Since $\ce{-CN}$ shows strong $\ce{-I}$ effect, there will be $\delta +ve$ charge on the carbon adjacent to it. Similarly, $\ce{-NO2}$ shows strong $\ce{-I}$ and $\ce{-M}$ effects. So I this is my ...
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1answer
347 views

Mechanism for conversion of imide to ester with NaH

What is the mechanism of this reaction? My proposed mechanism is shown below, would it work?
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31 views

How does electrophilic bromination with 1,2-dibromoethane work?

Hi I am trying to figure out the mechanism of a reaction containing a lithium carbanion and 1,2-dibromoethane in THF. The lithium carbanion is generated by deprotonating using LDA. Then 1,2-...
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25 views

What's the mechanism behind mineral oil loosening cyanoacrylate bonds?

Per industry literature I found that mineral oil is used to loosen out "super glue" and aid in removal from skin. I am exploring the chemistry of this loosening and I am intrigued. Please help me find ...
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52 views

Product of Diels-Alder reaction + Consecutive Reaction with base and heat

there is a problem regarding a Diels-Alder reaction that I do not understand (see image). The Diels-Alder reaction of the diene and the dienophile should lead to the product A. I hope I did it ...
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35 views

How do fuel/oxidizer combustion mechanics change when the constituents are supercritical?

The problem to solve is this: I want to create a heat generator [or heat absorber] that functions at atmospheric pressure to the pressure at the bottom of the sea. It will be used to drive a Stirling ...
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34 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 ...
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214 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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36 views

What is the mechanism of platinum as catalyst poisons on alumina?

I'm wondering if anyone knows by what mechanism is platinum (or other noble metals) catalyst on alumina substrate poisoned? Presently, I'm using platinum on alumina to decompose a hydrogen peroxide / ...
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32 views

Emergence of Lognormal distribution for the concentration of chemical compounds

I'm currently reviewing the literature about lognormal distributions describing/approximating the variability of a given chemical compound across different cells/ samples etc etc. The main argument ...
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91 views

most frequently used organic (name) reactions

The situation: Beside the relevant inventory in the Merck index, organic-chemistry.org lists 243 name reactions (as counted on 08-Feb-2018), the compilation by Kurti and Czako includes "250 selections"...
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60 views

Please explain the reason why E2 mechanism occurs

I known as that when the weak bases are reacting with 2° alcohol, E1 mechanism occurs. But, in the picture, E2 mechanism is occurred. Why E2 mechanism occurred? In step [3] Weak base : pyridine Did ...
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71 views

How did Zyklon hold and release HCN?

$\ce{HCN}$ is notoriously unstable: It boils at room temperature, and it tends to polymerize when concentrated in unbuffered liquid form. Yet $\ce{HCN}$ was for decades widely used as a fumigant ...
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255 views

Show that this mechanism is consistent with the rate law - how to?

The problem is from Principles of general chemistry, 2nd edition by Silverberg, chapter 16 problem no.81: "Even when a mechanism is consistent with the rate law, later work may show it to be ...
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42 views

Production of oxirane mechanism

Regarding oxirane production developed by Wurtz, is there an accepted mechanism? I carried out a research but couldn't find anything. My approach was this Is that correct?
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322 views

Reaction of 1,3 Butadiene with HBr in the presence of peroxides

I have learnt that the reaction of 1,3 Butadiene with HBr depends on the temperature as the temperature determines whether the reaction is under kinectic control or thermodynamic control. I believe ...
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136 views

What happens to promoters or poisons during a catalyzed reaction?

Catalysts are substances that influence reaction rates without undergoing changes in their mass and chemical composition, but may undergo physical changes. Promoters, poison etc. affect the activity ...
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1k views

Why these chemical reactions do not occur?

I have this list of reactions which don't occur: $$\ce{MgCl2(aq)} + \ce{K2SO4(aq)}$$ $$\ce{Fe(NO3)2(aq)} + \ce{SnCl4(aq)}$$ $$\ce{Cu(NO3)2(aq)} + \ce{FeBr3(aq)}$$ $$\ce{KCl(aq)} + \ce{CuSO4(aq)}$$ I ...
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Mechanism for the reaction between nitric acid and hydrochloric acid in aqua regia

After finding out that the following reaction takes place in aqua regia : $\ce {HNO_3 + 3HCl -> 2H_2O + Cl_2 + NOCl}$, I quickly got curious about what the mechanism for this interesting ...
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121 views

Mechanism of Biosynthesis of Terpenes

There is a specific part of the biosynthesis of terpenes that makes me confused: According to this mechanism, the double bond of the isopentenyl pyrophosphate attacks the primary carbocation, when it ...
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86 views

Why secondary alkyl groups are more prone to shifting than primary?

Why secondary alkyl groups are more prone to shifting than primary? I attach example from Grossman book [p. 20]: When $\ce{R} = \ce{CH2CH2Ph}$, the coordinated $\ce{Al}$ simply transfers a $\...
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2k views

Reactions of Grignard Reagents with amides

Can Grignard reagents add to amides? It appears from the synthetic pathway shown below that there has been some form of nucleophilic substitution at the carbonyl group. Source: 49th IChO Preparatory ...
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What can explain the more weight gain of aluminum coated steel than non-coated steel after NaCl immersion?

I have a 2 week experiment. I put aluminum coated and non-coated steel of the same size and shape in separate beakers with NaCl solution. Both are sealed. But, I am surprised that Al coated steel ...
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187 views

Reaction of HBr + 2,4-dimethylpent-1,3-diene yields 3 products?

My understanding is that either pi bond can react with HBr but that you still have to follow Marovnikov's rule or whatever. I end up with 2 allylic carbocations that are actually the same molecule ...
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20 views

Comparison of ways to provide energy to a reaction

As we all know, you can provide energy to a reaction to overcome the activation energy of a reaction by heating the reaction. I have, however, recently sat through a talk where someone 'powered' a ...
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47 views

Abiogenesis: Formation of Lipids from Montmorillonite

I have been really interested in scientific hypotheses regarding abiogenesis, particularly the lipid-world hypothesis. However, I could not find information on the chemical pathway that leads to the ...
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64 views

Hoffmann's rearrangement

In Hoffmann's rearrangement of acid amide...the OH from the basic medium attacked the H ..now my question is...isn't the carbonyl carbon more acidic as it's surrounded by 2 electronegative elements?