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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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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409 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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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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125 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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132 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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132 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 ...
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588 views

Oxidation of dihydropyridine

This is a step in a experiment I have carried out. Usually DDQ (dichlorodicyanoquinone) would be used here to oxidise the dihydropyridine. However in this case Nitric Acid is being used as the ...
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830 views

Can two solids form in a double displacement reaction?

I am trying to react silver flouride with magnesium chloride. I know it is a double displacement reaction but so far the equation I have gotten is: $$\ce{2AgF (aq) + MgCl2 (aq) -> MgF2 (s) + 2AgCl ...
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567 views

Experimentally proving the mechanism and rate laws of SN1 & SN2 reactions

I have been given the task of experimentally proving the rate laws and mechanisms of $\mathrm{S_N1}$ and $\mathrm{S_N2}$ reactions. Unfortunately, the only equipment I can use is limited to analytical ...
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123 views

Asymmetric Suzuki coupling - saturated alkyl chain

9-BBN is applied for Suzuki coupling of a saturated alkyl chain with some alkenyl,alkynyl or even secondary alkyl halide like the modification attached: (Saito, B.; Fu, G. C. Alkyl−Alkyl Suzuki Cross-...
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115 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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230 views

Synthesis from cyclic ketone to alcohol

How can I make the product in the picture below from cyclohexanone? I did Stork enamine synthesis, but it results in terminal primary alcohol. I need secondary alcohol with one more carbon atom at end....
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2k views

Mechanism for reaction between hydrochloric acid and magnesium

Balanced equation: $$\ce{Mg(s) + 2HCl(aq) -> MgCl2(aq) + H2(g)}$$ However, Cl- is a spectator ion so the actual reaction equation is: $$\ce{Mg + 2H+ -> Mg^2+ + H2}$$ Here is my proposed ...
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2k views

Oxidation of alkenes by selenium dioxide to diketones

I know that $\ce{SeO2}$ readily affects the allylic position. The reaction mechanism of this reaction goes like this: (Source: Wikipedia; License: Public Domain) But, in my book, there's another ...
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314 views

Why does RCN attack the benzene ring in Hoesch Reaction?

In the Hoesch reaction, an alkyl cyanide reacts with a polyhydric benzene ring, and forms an imine salt by attacking the activated benzene ring. Most acid derivatives (and even alkyl cyanide itself ...
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How to break down soap and detergents?

I am building a greywater harvesting system. It is a 3-stage system: The 1st stage breaks down soap and detergents. The 2nd stage filters the water. The 3rd stage pumps water out of system. What ...
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1answer
98 views

Does presence of alkyl groups on alpha carbon increase yield of alkane in Kolbe's Decarboxylation?

We know that, during the synthesis of alkanes by Kolbe's Decarboxylation reaction, the reaction proceeds via a free radical $\ce{R.}$ at the anode. So, an alkyl group, say methyl, when substituted at ...
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4k views

Why does adipic acid give a cyclic ketone on heating while glutaric acid and succinic acid give a cyclic anhydride?

Why does adipic acid give cyclic ketone on heating while glutaric and succinic acid give cyclic anhydride?
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1answer
179 views

What are the parameters of protonation of a molecule?

Adding an acid replaces the $\ce{-MgBr+}$ with an $\ce{H+}$. Why does this happen? Is $\ce{H+}$ a better electrophile than $\ce{MgBr+}$? Or, to put it another way, why doesn't $\ce{MgBr}$ stays ...
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1answer
879 views

Why are acid catalysed reactions of carbonyl compounds reversible?

I am currently studying aldehydes and ketones and their reactions. I've noticed that acid catalysed reactions are represented with reversible arrows, while base catalysed reactions are shown with ...
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2k views

Reaction of alkyne with sodium in ethanol

What is the product obtained on the reaction of but-2-yne with $\ce{Na}$ in ethanol? I know that $\ce{Na}$ in liquid $\ce{NH3}$ converts an alkyne to an alkene by anti addition, and $\ce{Na}$ in ...
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49 views

Parameters by which to distinguish SN1 from E1

I am new to organic chemistry and am struggling with the following very basic question: Given is the following reaction: $$\ce{(CH3)3CCl + NH3(aq) →}$$ I am supposed to analyse the end-product (the ...
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How can I determine the electrode potential of ethanoic acid redox reaction?

I'm conducting a research paper on the effect of surface area ratio from anode to cathode and the electrode material on the rate of electrolysis of ethanoic acid by measuring the volume of carbon ...
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Why is there only little difference between molecular dipole moments in CHX3 compounds (X = Cl, Br, I)?

Why is there only little difference between molecular dipole moments in $\ce{CHX3}$ compounds ($\ce{X}$ = $\ce{Cl}$, $\ce{Br}$, $\ce{I}$)? As we can see there is a huge difference in dipole moment of ...
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Will 1-[2-(chloromethyl)phenyl]propan-2-one, follow a Williamson ether synthesis route or, a Diels-Alder reaction?

I was asked to find the product of potassium ethoxide reaction with 1-[2-(chloromethyl)phenyl]propan-2-one (1). I came up with two different paths, each leading to the same product. 1-[2-(...
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57 views

Rationale behind Barton's rules for catalytic hydrogenation

Organic Chemistry by Morrison and Boyd,Seventh Edition says - When cyclohexanones are used as substrates, the stereoselectivity of the reduction is found to be dependent on the acidity or the ...
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39 views

Halogen bonding in organic reactions

Recently, a group of researchers from the Nanyang Technological University in Singapore have investigated the novel $\ce {S_N2X}$ mechanism which involves a "frontside attack" on the substrate, rather ...
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88 views

Why are “diene” structures in the C-ring of anthocyanins singled out for their singlet-oxygen quenching ability?

Anthocyanins are a class of water-soluble vacuolar pigments. They are sensitive to pH, and can undergo a series of structural changes according to a pH-dependent equilibrium as illustrated in Figure 1....
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194 views

Mechanism for the addition of chlorine to benzene to form hexachlorocyclohexane

I am familiar with electrophilic substitutions of benzene, with chlorine using a halogen carrier catalyst such as $\ce{AlCl3}$, to produce chlorobenzene, and I am aware of the mechanism. But, ...
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66 views

Chugaev and Selenoxide Elimination giving different products

In class we are going over intramolecular elimination. In this question I will provide two similar reactants that provide a different mixture of products. The chugaev elimination gives a 50/50 ...
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122 views

Diazo Coupling reaction with para substituted phenol?

Usually Diazo coupling occurs at para position until the para position is occupied , in which case coupling occurs at ortho position . While solving questions I found in both the cases as shown , ...
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31 views

Oxidative Addition - Really concerted?

I guess you are all familiar with the oxidative addition or reductive elimination reaction in organometallic chemistry. If you read further into the topic you may find different pathways like via ...
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217 views

Abnormal reaction of grignard reagent

My book states that: When isopropyl magnesium bromide is added to diisopropyl ketone, the expected tertiary alcohol is not obtained; instead the secondary alcohol; diisopropyl carbinol is obtained ...
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223 views

Reaction between Salicylaldehyde and 2-Benzoylpyridine

In a paper by Sheng et al (10.1016/j.dyepig.2018.07.036) the authors synthesize the compound MZC as shown in the scheme below. I'm looking for information about what the reaction mechanism is that ...
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374 views

Mechanism of oxidation of phenol to quinone by chromium(VI)

In the supplementary information for Org. Lett. 2005, 7 (19), 4297–4300, the following experimental method for the synthesis of 2-bromo-6-methylcyclohexa-2,5-diene-1,4-dione is given: To a ...
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157 views

Major product of isomerization reaction

I am trying to come up with a logical mechanism for the following transformation, where 2-methylenecyclobutan-1-ol is converted to cyclopentanone under acidic conditions: What I have tried to do was ...
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80 views

Do Sodium Alkynides react with esters in the same way that Grignard reagents do?

We know that Sodium alkynides react with aldehydes and ketones like Grignard reagents. But do they behave the same way with esters?
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Organic chemistry. how to control the Friedel–Crafts alkylation rection to methylbenzene as the major product?

My question is due to a discrepancy I founnd in reactivity and organic conversions. In reactivity of organic compounds it has been established that an alkyl group activates the benzene ring and hence ...
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111 views

Mechanism of photochemical hydroamination with LDA

I've recently come across a couple examples of intramolecular alkene hydroamination accomplished by treatment with LDA followed by visible light irradiation (tungsten light bulb):[1,2] I'd assume ...
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507 views

Mechanism for reaction of an allene with the Grignard Reagent(RMgX)

How does the Grignard Reagent($\ce{RMgX}$) react with an allene $\ce{CH_2=C=CH_2}$ and what are the products formed? This is exactly what I tried to do. Any help will be appreciated.
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536 views

Comparison of the rate of SN1 and SN2 reaction

It is known that $\mathrm{S_N1}$ (Substitution Nucleophilic Unimolecular) follows the order of rate of reaction: Tertiary ($3^\circ$) > Secondary ($2^\circ$) > Primary ($1^\circ$) For $\mathrm{...
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Nucleophilic Substitution rate comparison 1-bromobutane and 2-bromo-2-methylpropane with NaOH

I want to ask a question about the hydrolysis of haloalkanes to form alcohols. I have been presented with a flowchart diagram of possible reactions of haloalkanes below: Now, I have been presented ...
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2k views

Which is the correct mechanism for the ozonolysis of an alkyne?

According to Organic Chemistry by Jonathan Clayden, Nick Greeves and Stuart Warren (2nd edition), the mechanism for alkene ozonolysis is given as In Advanced Organic Chemistry, Part B: Reactions and ...
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Insertion vs epoxide formation

How can it be explained that in the first reaction mentioned below, a 7-membered ring dominates when the leaving group is nitrogen and an epoxide forms when the leaving group is dimethyl sulfide? ...
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256 views

Mechanism for conversion of gem-dihalide to carbonyl compound

How does nucleophilic substitution work in a compound consisting of two leaving groups? I understand that hydroxide ions will attack the carbon centre (which bears a partial positive charge) and ...
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159 views

Meisenheimer complex in Preparation of 2-Naphthol from 2-Naphthalenesulfonic acid

I'm trying to figure out the addition-elimination mechanism for the preparation of 2-naphthol from 2-naphthalenesulfonic acid. I know that the $\ce{SO3^2-}$ group is functioning as the leaving group, ...
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106 views

Chemistry Behind TMOS Aerogel

I have found out how to make silica aerogel. Currently, the solution that I need to create to make the gel requires tetramethyl orthosilicate or TMOS. Furthermore, the procedure requires me to make ...
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165 views

How does the rate determining step determine the overall speed of the reaction if it is the first step in the reaction?

I can imagine it determining the rate of the whole reaction if it is the last step since that means that we will have lots of the reactants needed for the rate determining step, synthesized in earlier ...
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1answer
163 views

Formation of trifluoride anion

I wanted to understand mechanism of the formation of $\ce{F3-}$ anion through the molecular orbital theory. UPDATE - What I really want to know is that when $\ce{F3-}$ is formed from $\ce{F2-}$ and $\...
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485 views

Dehydration: Methylcycloexanol + H2SO4 + THF

I came across this exercise: Why do we need THF? How the THF influence the mechanism? I couldn't find any link or external explanation, if you do please share. Thanks in advance.