The detailed and 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, which seek information on elementary steps of these processes. It may be applied to hypothetical and/or proposed ...

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Mechanism for acid-catalyzed dehydration of 2,3-dimethylcyclopentanol

How do you get from 2,3-dimethylcyclopentanol to 1,2-dimethylcyclopent-1-ene? I know the -OH group leaves as water (being protonated by acid) forming a carbocation. Then the weak nucleophile (water) ...
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a chemical model for pde

Consider the initial boundary value problem $$u_t=a(t)u_{xx},\,\,\,0<x<1,\,\,\,t>0$$ $$-ku_x(0,t)=hu(0,t),\,\,\,t>0$$ $$u(1,t)=u_0,\,\,\,t>0$$ $$u(x,0)=f(x),\,\,\,t>0$$ where ...
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12 views

What radius best represents reaction distance?

Molecules must be within a certain distance for a reaction to begin as well as satisfying a myriad of other factors. Whilst the exact distance varies from reaction to reaction, is their any ...
5
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1answer
55 views

Mechanism for formation of amide by reaction of amine with ester

This is the mechanism given in my lecture handout: I have a problem with the third species along. Surely the negatively charged oxygen would protonate before the other oxygen would. Also, why does ...
4
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1answer
49 views

Amide synthesis SM alkylchloride

In this question immediate reaction is to make a grignard reagent with B by reacting it with magnesium and have it attack $\ce{COX(N(Me)2)}$ to form $\ce{C}$ Im not sure how it would be possible to ...
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1answer
84 views

Alkylation of alkenes by nucleophilic substitution

A double bond/alkene reacts as a nucleophile. I have never seen a reaction where it takes part in an $S_N1$ or $S_N2$ reaction with a halogenoalkane for example. This would presumably be a very useful ...
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36 views

Naproxene syntheses: electrophilic aromatic substitution on activated naphthalene

I am studying Syntex's naproxene syntheses and I came across a couple of electrophilic substitutions whose mechanism I can't understand. The first one is a Friedel-Crafts acylation: the products are ...
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1answer
52 views

Can carboxylic acids be used in the aldol reaction?

A question in a practice paper I did recently showed the aldol condensation of benzaldehyde with ethanoic acid. I think I am right in saying that carboxylic acids do not form enolates because the ...
3
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1answer
32 views

Oxymercuration Demercuration Mechanism doubt

I'm having a doubt on the mechanism of oxymercuration Demercuration reaction. How does the reaction, initially heading towards anti addition(after cyclic transition state formation) ,get spoiled by ...
3
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1answer
30 views

Mechanism of enolether formation with ethyl orthoformate in estr-4-ene-3,17-dione (Djerassi's norethisterone synthesis)

The second step of Djerassi's synthesis of 19-nor-17α-ethynyltestosterone (norethindrone), involves the protection of the ketone in position 3 via enolether formation, as in the picture: What is ...
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1answer
56 views

Effect of different electron withdrawing/transition state stabilising groups in nucleophillic aromatic substitution

I have been asked the following question in my problem sheet: The only differemce between reaction A and reaction B is the electron withdrawing group that stabilises the anionic transition state ...
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Calculate the number of moles of NO₂ (g) produced per hour per liter of air?

A reaction of importance in the formation of smog is that between ozone and nitrogen monoxide described by $\ce{O3(g) + NO(g)->O2(g) + NO2(g)}$ the rate law for this reaction is: rate of ...
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2answers
60 views

Claisen Condensation to Ketone

Can someone explain (and preferably draw) the intermediates of this reaction? I understand that it is a Claisen Reaction, and likely a condensation due to the heat, but I am not sure why there ...
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1answer
25 views

In regards to the addition of hydrogen to alkynes, does the amount of moles of Hydrogen matter?

Is there any difference between having the addition of 1 mole of hydrogen to 2-pentyne with a platinum catalyst compared to the addition of 2 moles of hydrogen(H2). I was under the impression that ...
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1answer
21 views

Reaction of ethylacetoacetate with Iodine

A "reaction map" in my lecture handout suggests that the product of this reaction is: So, basically overall it just merges two ethylacetoacetate molecules together at the central carbon. What is the ...
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1answer
34 views

Decarboxylation product of bicyclic compound

What is the decarboxylation product of the following species: It may seem straightforward but the product enolate involves a double bond with one end at the bridgehead carbon which is ...
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1answer
35 views

Mechanism for the formation of butanoic acid from ethylacetoacetate

My problem sheet asks me: "Draw a mechanism for the formation of $\ce{EtCH2COOH}$ from the reaction of $\ce{MeCOCH(Et)COOEt}$ with $\ce{NaOH}$ in $\ce{EtOH}$" This has got me stumped. The mechanisms ...
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1answer
43 views

What determines whether an aldol reaction will occur again or eliminate?

The product of an aldol reaction is a $\beta$-hydroxy ketone. This can go on to eliminate to form an alkene thus: However, the species on the far left of the above diagram (the $\beta$-hydroxy ...
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1answer
26 views

What happens to a molecule when it is unstable?

I'm just starting OChem and I see that for a SN1 reaction, the rate of the reaction changes with the number of alkyl groups attached to the carbocation that is formed. The textbook (Klein) explains ...
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can phenylethene be made like this from ethane and benzene?

step1: dehydrogenate ethane to ethene step2: dehydrogenate ethene to form ethyne step3: add HCl to ethyne to form chloroethene through addition reaction step4: add benzene to chloroethene to ...
2
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1answer
43 views

What is the reason for strong acids/bases dissociating in water?

I have read that the actual definition of a strong acid is one which will fully dissociate in water, so please do not turn the problem on its head when answering. It is also my understanding that ...
2
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1answer
41 views

Why do Allylic Halides prefer SN2 reaction over SN1?

As explained by my instructor, Allylic Halides form highly stable Transition States. They are stable because they are: $sp^2$ hybridized possess a conjugated system of pi bond and empty ...
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1answer
56 views

Difference between Intermediate and Transition State

Can someone please explain what exactly the difference between an intermediate and a transition state is? I understand that they are formed as part of the process in converting the reactants to ...
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27 views

How do tie-line slopes affect raffinate/extract envelope in ternary phase diagrams?

I am struggling to understand ternary phase diagrams for reactor engineering. The course slides offer little to no help so I'm hoping to find an answer to this question How does the slope of the ...
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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 ...
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1answer
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Reactions of alkynes and Sodium or soda amide [closed]

What happens when alkynes react with Sodium or soda amide? Does it liberate hydrogen so does it prove that alkynes are acidic? What happens when But-1-yne and but-2-yne react with Sodium and soda ...
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95 views

Can Hydride Shift and Methyl shift happen one after another in a carbocation?

Can hydride shift be followed by methyl shift for stabilizing a carbocation? In case both is possible which will occur first?
3
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1answer
64 views

Reduction of amide with LiAlH4

In reduction of carboxylic acid with $\ce{LiAlH_4}$ the first step is deprotonation. But in the mechanism of reduction of amide with $\ce{LiAlH_4}$ (here), the first step is addition of hydride on ...
5
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3answers
104 views

Comparing SN2 reaction rates

I've read in 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: As you can see , it is a question ...
3
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0answers
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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 ...
5
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1answer
69 views

Reverse Friedel-Crafts mechanism

I need to find a mechanism for the above reaction but I cannot make much progress. I do have something in mind but it doesn't seem entirely plausible: First the tert-butyl group leaves (this seems ...
9
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2answers
223 views

Chlorosulfonation mechanism

The above reaction looks very similar to a conventional sulfonation reaction but if the reaction pathway is analogous to sulfonation I do not see how the $\ce{SO_2Cl^+}$ would form. Surely ...
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1answer
99 views

Mechanism of styrene dimerization

I am struggling to find a mechanism for the above reaction. So far I have suggested that the proton adds to one of the reacting aromatic species leaving the resonance stabilized secondary cation. ...
4
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1answer
103 views

Why do E2 reactions (dehydrohalogenation) only occur when the hydrogen and leaving group are in the same plane?

E2 reactions (dehydrohalogenation) only occur when the hydrogen and leaving group are in the same plane. I can't think of a reason that they would need to be in the same plane, so what is the reason ...
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1answer
25 views

Ionize Hydrogen and Oxygen Gas in Electrolytic Cell?

As is well known, water can be electrolyzed into oxygen and hydrogen gasses. However, all redox reactions can be run in reverse. If I were to electrolyze water in 2 closed containers (in order to trap ...
3
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1answer
43 views

Is there a list of known rate laws for reactions?

I've been scouring the web for a website/pdf that lists reactions and their corresponding rate laws. Something like: \begin{align} \ce{A + B &-> C} & ...
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81 views

Fluorescein synthesis

What is the mechanism of the fluorescein synthesis performed by von Baeyer?
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3answers
65 views

Why does basic peroxide react via conjugate addition rather than through direct addition?

The following reaction occurs: The $\ce{HOO^{-}}$ ion reacts as a nucleophile at carbon number three and consequently the reaction is conjugate addition. However, Why would a peroxide not react ...
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1answer
51 views

Why aryl halides are very less reactive towards nucleophilic substitution reactions? [duplicate]

I've often herd that aryl halides are very less reactive towards nucleophilic substitution reactions. One of the reasons for this I found was that there is resonance effect in the compound, but how is ...
3
votes
1answer
99 views

Identifying rearrangement reaction?

I was asked to solve this problem, and the answer key shows this: I'm not sure what's going on here, but it looks like some sort of a rearrangement and reduction. Is it an internal reaction between ...
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22 views

Methylene Blue Photo-initiation PH

I am working on a project using methylene blue as photo-initiator for a polymerization reaction. In this classic reaction methylene blue will get reduced into leuco-methylene blue in presence of some ...
3
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1answer
50 views

Why does phosphorus tribromide act as a Lewis acid (electron acceptor)?

This question is purely out of curiosity and to help me remember the "why" of a mechanism to help me remember the "what/how". In organic chemistry we recently studied the Sn2 Substitution of Primary ...
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1answer
60 views

Why, during aspirin synthesis in acidic conditions, anydride carbonyl oxygen is protonated rather than salicylic acid carbonyl oxygen ?

The common route for aspirin synthesis (described here) employs acetic anhydride and salicylic acid, in acidic conditions. The first step of such a reaction mechanism is the protonation of the ...
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1answer
46 views

Attack of amine on amide

I am confused with the last step of clozapine synthesis: How can the amine group attack the amide group to form the amidine in such acidic environment? Is the intermolecular reaction between an ...
5
votes
1answer
346 views

What is the major product on chlorination of 2-methylbutane?

I came across a question asking for the major product on chlorination of 2-methylbutane. The answer in the back of the book says it will be 2-chloro-3-methylbutane. However, I thought the major ...
5
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1answer
89 views

Amine addition to nitro group

What is the mechanisms of this reaction? How feasible is this reaction? Can it happen under not too much vigorous conditions if it were intermolecular?
7
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155 views

What will be the major product on chlorination of m-nitrophenol?

I came across a question asking for the major product on chlorination of m-nitrophenol. In my opinion the deactivating nature of nitro group should control the regioselectivity, but I found out the ...
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1answer
44 views

Aluminum deoxidation gas

I am new to chemistry. I am looking for a gas that would de-oxidise aluminium. Which gases would work for that and at what temperature? Details: I need to sinter aluminium powder. But because the ...
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1answer
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How does NMO reform Osmium tetroxide after reaction with an alkene?

After Osmium tetroxide adds to a double bond and is then hydrolysed the following species is formed: Because Osmium tetroxide is toxic, NMO is used to transform the above back to Osmium tetroxide. ...
4
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1answer
85 views

Ozonolysis of nitronate

What is the mechanism for the ozonolysis of a nitronate anion? What gas is produced in this reaction? Is there any chemoselectivity in the presence of a double C=C bond in the molecule?