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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.

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645 views

Mechanism for reaction of aryl diazonium with potassium iodide

I’m working on a synthesis problem that requires me to draw the arrow mechanism for the second half of the Sandmeyer reaction. Basically it’s the halogenation of an aryl diazonium compound. Typically ...
0
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0answers
133 views

Transition states in Gaussian don't look right

I've been trying to run some calculations on a reaction I observed in the lab involving an epoxide opening and subsequent rearrangement. I have optimized my starting compound, the intermediate ...
1
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1answer
662 views

Reaction of dihalides with excess of NaNH2

Gem-dihalides react with $\ce{NaNH2}$ to give terminal alkynes. Why is a terminal alkyne prefered? For example, I had thought that 2-pentyne would be preferred over 1-pentyne as it would be more ...
6
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1answer
146 views

Hydroboration oxidation reaction on trans,trans,trans-1,5,9-cyclododecatriene with carbon monoxide

The given solution: I got this question in an entrance exam coaching test paper in India. Product P is easily covered by the mechanism of simple hydroboration-oxidation reaction, and I've understood ...
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1answer
137 views

Shifting of groups in carbocation rearrangement

Phenyl has greater migratory power. However, why did methyl migrate in step 2 of the reaction?
9
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1answer
86 views

Why is the initial carbocation not formed adjacent to the phenyl moiety?

I know that after rearrangement the carbocation is more stable, but we should protonate the compound first where the carbocation it is more stable, i.e. adjacent to the phenyl group. Why do they ...
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0answers
130 views

What is the balanced equation for FeCl3 in water? [duplicate]

I'm trying to figure out the balanced equation for $\ce{FeCl3}$ with water. I know that $\ce{HCl}$ is probably formed (see here) but I don't know the rest. I can't find anything on this!
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0answers
38 views

Effect of interaction between lactic acid and glucose monohydrate on optical rotation

Would anyone know why I get double the expected optical rotation (OR) result for a solution containing D(+)-glucose and L(+)-lactic acid in comparison to a solution of D(+)-glucose on its own? When I ...
4
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0answers
80 views

Hydroboration oxidation reaction on trans,trans,trans-1,5,9-cyclododecatriene [duplicate]

The given solution: Could some one please explain the mechanism of the reaction? How it proceeds and why it proceeds that particular way? Also, what is the use of $\ce{CO}$?
0
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3answers
74 views

Is it possible to prevent sacrificial anode contaminate the soil?

I have a mild steel pipe (black pipe, NOT zinc plated) water well. My question: is it possible to somehow put a sacrificial anode in an electrolyte contained in a bucket instead of burying it in the ...
0
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1answer
53 views

Acid promoted Enol ring formation Mechanism

I know this has to be an enol mechanism but which carbon gets attacked by the $\pi$ electrons?
3
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2answers
181 views

Half life of Nitrofurantoin

Both wikipedia and Toxnet list the half-life of Nitrofurantoin as 20-60 minutes in the blood plasma. Can anyone explain how this is so short, especially for an antibiotic, and how it still has time to ...
10
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1answer
273 views

Mechanism of lithium-halogen exchange of primary alkyl iodide

On Clayden's page 190 this reaction is given for preparation of organometallics: What is the mechanism of this reaction? I expected the "almost carboanion" part of the $\ce{t-BuLi}$ to attack as a ...
2
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0answers
94 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 ...
3
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1answer
1k views

Reaction of anisole and succinic anhydride in presence of aluminium chloride

Predict the structures of the intermediates/products in the following reaction sequence: In the first step, I know that aluminium chloride is playing some role, as otherwise hydronium ion ...
1
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0answers
49 views

Why is SN1 mechanism followed in diazo aromatic compounds' nucleophilic substitution?

There is considerable evidence that SN1 mechanism is followed in diazo aromatic compounds' nucleophilic substitution. I would like to know the reason for this and why is it preferred to SNAr mechanism ...
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0answers
55 views

is rydberg constant and rydberg unit are same? [closed]

i want to ask a question that.is rydberg constant and rydberg unit are same. UNIT OF RYDBERG CONSTANT IS m^-1, right? Then what is rydberg unit.
4
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0answers
146 views

Mechanism for reaction of enol ether with HBr

Please refer to the image for the question. I tried two different mechanisms for the reaction (1 and 2) and ended up with two different products. Now I can't decide which of the two mechanisms would ...
5
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1answer
239 views

Nitrosonium ion in the nitration of phenols

Peter Skyes mentions in the book Guidebook to Mechanism in Organic Chemistry (6th ed.) on p. 137 that: Highly reactive aromatic compounds, such as phenol, are found to undergo ready nitration even ...
4
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1answer
141 views

Reaction of alkyl bromide in presence of piperidine

What are the products of this reaction? I believe there'll be E2 elimination to give the products. Not sure. Help would be greatly appreciated. The above is the product which I thought might be ...
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0answers
77 views

Mechanism for the formation of an alkyl halide from alcohol and phosphorus trihalide [duplicate]

I was reading about synthesis of alkyl halides from $\ce{PX3}$. I want to know the mechanism for this reaction. According to Solomons and Fryhle, no rearrangement takes place in case of $\ce{PBr3}$ , ...
5
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1answer
130 views

Base-promoted rearrangement of β-ketoester

Propose a reasonable mechanism for the following transformation: I guess an enolate probably forms first, but then what does it attack to give something like the product in the question?
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0answers
34 views

Propose mechanism for trisubstituted olefin synthesis via Ni-catalyzed hydroalkylation

The synthesis scheme for trisubstituted olefin synthesis via Ni-catalyzed hydroalkylation: My proposed mechanism: The cyclopentane product implies the mechanism goes through a radial, as well as $\...
6
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1answer
91 views

Mechanism for the conversion of an unsaturated alkyl halide to an alcohol

Question: Predict the mechanism for the following reaction: Attempt: I thought it will proceed through SN1 mechanism as $\ce{H_2O}$ is involved (solvolysis). So I proceeded with the ...
4
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1answer
109 views

Mechanism for the conversion of dimethyl cyclohexa-1,4-diene-1,2-dicarboxylate to dimethyl benzene-1,3-dicarboxylate using bromine

Question Convert the first compound into the second using only $\ce{Br2}$ I tried solving it by making a 3-ring with $\ce{Br+}$, and then making one of the oxygens break that ring. Than I used $\...
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1answer
401 views

Mechanism for Chromyl Chloride Formation

This is the very famous chromyl chloride test, used for detection of chloride ion in solution - $$\ce{K2Cr2O7 + 4NaCl + 6H2SO4 -> 2CrO2Cl2 + 2KHSO4 + 4NaHSO4 +3H2O}$$ When a mixture containing ...
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1answer
136 views

Why is the Diels-Alder reaction a syn addition?

It is said that the Diels-Alder reaction is a syn-addition with respect to both the dienophile and the diene. Is there a reason for that!?
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1answer
30 views

Why is manganese oxide precipitated during the syn hydroxylation of alkenes with permanganate ion?

During the hydrolysis step, after the formation of the heterocyclic ring, hydrogen permanganate ion is formed but the final product is manganese oxide precipitate. My point - why would permanganate ...
0
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1answer
129 views

Carbocation Stability: Tertiary versus Secondary Benzyl for Hydrobromic Acid Addition

I haven't been able to find anything concrete or consistent on this topic. For the following reactions, which product would be favored, assuming that they both have to go through a carbocation ...
0
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1answer
97 views

Which mechanism is not seen during hydrolysis of esters? [closed]

Which mechanism is not seen during the hydrolysis of esters? AAC2 BAC2 AAL2 BAL2 AAC1 I know that hydrolysis of ester is pseudo-first order reaction but I found this question where ...
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0answers
186 views

Why do stable enols give positive ferric chloride test?

It is known that phenol and all its derivatives give violet colour with neutral alkaline ferric chloride solution. However I also found out that stable enols, like 2,4 di-oxo pentane, also give this ...
8
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2answers
603 views

What is the actual mechanism of Fenton reaction?

Fenton reaction was supposedly discovered by Fenton as Tartaric Acid oxidation by hydrogen peroxide in presence of ferrous cation in 1894. Research Paper link. I have worked on this reaction for ...
3
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2answers
217 views

Why does the E1cb mechanism proceed in the specific way it does?

We have been learning the E1cB mechanism in organic chemistry, but we have not been delving into the motivation as to why this mechanism occurs instead of others. Consider the following mechanism: I ...
5
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2answers
237 views

The difference between elementary and concerted reactions

In the IUPAC Gold Book: elementary reactionA reaction for which no reaction intermediates have been detected or need to be postulated in order to describe the chemical reaction ...
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1answer
43 views

What makes bond break apart from heat? [closed]

What makes bonds break apart from heat? I am wondering if anyone could explain the reasons why new bonds are formed in the absence of energy. I have found that they form in order to lower the overall ...
9
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2answers
425 views

Reaction between a carbene and n-pentane

Does the following reaction occur when n-pentane reacts with methylene or does it form some other simpler products due to the reactivity of the carbene? $\ce{CH3-(CH2)3-CH3 + :CH2-> CH3-(CH2)4-CH3}...
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1answer
55 views

Help understanding external magnetic field sensitivity of radical pair reaction rate

Two recent papers have been published on magnetoreception in birds. In this case it is the ability of the birds to sense the direction of the Earth's magnetic field potentially for navigation. ...
4
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1answer
307 views

Reaction of conjugated alkene with KNH2

I could not think of this reaction fitting into any of the reactions I know except the aryne mechanism. And hence I came up with the following mechanism after seeing the answer (which I've written in ...
4
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0answers
218 views

Textbook suggests secondary alkyl halides do not undergo SN1 reaction

The 8th edition of Organic Chemistry by Paula Bruice suggests that secondary alkyl halides do not undergo SN2 reactions. However, many other sources state the opposite. So, what is the correct answer? ...
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1answer
595 views

Calcium carbonate and hydrochloric acid

I am trying to solve an exercise, where a block of 605.5g calcium carbonate should be completely dissolved in 30% hydrochloric acid (w/w) and the concentration of the acid should be 3% in the end. The ...
0
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1answer
274 views

Role of solvents in ozonolysis and oz0nolysis of alkynes with water [closed]

My text book says that when an ozonide (formed from an alkene) is treated with $\ce{Zn/CH3COOH}$, it cleaves to give carbonyl Compounds. 1) Does $\ce{ Zn/CH3COOH}$ mean Zinc in acetic acid (or) zinc ...
3
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2answers
47 views

Regenerating a Cobalt Acetate Catalyst

I have an eluent from an ion-exchange column containing Cobalt (II) ions and Chloride ions. In order for the cobalt catalyst to be recycled to the main process, it must be in its acetate form. Is ...
0
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1answer
203 views

Hydroxyl group to free amine in polyethylene glycol using CDI?

For converting $\ce{OH}$ of methylated polyethylene glycol. The first step is converting hydroxyl group to imidazole carbamate as an active intermediate. But what about the next step? If I will add ...
2
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1answer
141 views

Prins reaction mechanism

I am trying to figure out the product for the following reaction: Its a Prins Reaction. My proposed mechanism for it is: In my second step, that particular carbocation is formed since $\ce{Ph}$ is ...
6
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1answer
392 views

Mechanism for conversion of ketone to dichloride with phosphorus pentachloride

I would like to know the mechanism of this reaction leading to the formation of a geminal dichloride. I am unable to predict how the $\ce{C=O}$ breaks and how the 2 $\ce{Cl}$ atoms replace the oxygen ...
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0answers
75 views

Compare rate of hydrohalogenation between 1,2-diphenylethene and 1-phenylpropene

Consider the compounds, (I) - 1,2-diphenylethene and (II) - 1-phenylpropene. Compare their rate of hydrohalogenation (HX addition) I feel that the answer should be (II) > (I), but to my surprise it's ...
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2answers
105 views

Why is it only electrons that take part in chemical reactions?

I learnt that only electrons take part in chemical reactions and the protons do nothing (neutrons are electrically neutral, so they do nothing). Why is this so if the protons are positively charged ...
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1answer
134 views

What anions does the loss of a proton from HOCN and HNCO produce? Are they same or different?

What anions does the loss of a proton from $\ce{HOCN}$ and $\ce{HNCO}$ produce? Are they same or different? Once, I had asked my teacher if $\ce{HCN}$ and $\ce{ HNC }$ are different or same compunds, ...
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0answers
39 views

Transformation of an epoxido-carboxylic acid to an aldehyde [duplicate]

So I am battling with the last part of this transformation and was hoping someone could explain this mechanism to me so that I can confirm my answer. Treating an alcohol with a strong hydrohalic ...
3
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1answer
121 views

Ring expansion of two fused rings to a larger ring

I saw the following reaction mechanism in paper Tetrahedron Lett. 1976, 17 (33), 2869–2872.: I'm not able to understand the following parts: How did the conversion of 27 to 29 take place? I've never ...