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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105 views

SN1, SN2 and enantiomeric excess

When (R)-2-bromobutane is heated with water, the $\mathrm{S_N1}$ substitution proceeds twice as fast as $\mathrm{S_N2}$. Calculate the appropriate enantiomeric excess and the specific rotation of the ...
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Method for removing CuO in an inert environment

Common oxides (i.e., CuO or Al2O3) are capable of removal via NaOH solution. However, I am interested in removing a copper oxide layer inside an inert (Ar glovebox) environment. Thus, the traditional ...
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29 views

How to rationalise the difference in reactivity between alcoholic and aqueous KOH with alkyl bromides? [duplicate]

Why is it that when we use alcoholic $\ce{KOH}$ with say $\ce{R-Br}$, E2 elimination occurs, whereas with aqueous $\ce{KOH}$, SN reaction takes place, as both have the same nucleophile, ie $\ce{OH^-}$?...
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When 2-pentene reacts with HBr, what will be the major product?

If we consider the first step (formation of carbocation by the attack of the proton). A couple of textbooks I referred say that when the substituents on the $\ce{C=C}$ are different, the direction of ...
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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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61 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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2answers
717 views

Reaction of coumarin with phenylmagnesium bromide

I came across this problem.. I thought that the Grignard reagent, PhMgBr, would cleave the lactone and then subsequently add to the ketone formed, giving an allylic tertiary alcohol after aqueous ...
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190 views

Role of zinc chloride in reaction of ether

I am trying to do a reaction between acetyl chloride $\ce{CH3COCl}$ with diethyl ether. I know that upon using anhydrous $\ce{ZnCl2}$ and heat, I'll get an ester and an alkyl chloride, but I'm not ...
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Rate law of the reaction of propane with oxygen

In class, I have a demonstration where I light a bubble filled with propane. As I add oxygen, the bubbles combust faster and more quickly. I have already balanced out the chemical reaction like so: $$...
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1answer
2k views

Ether cleavage with conc HBr

I've been asked to draw the mechanism by which benzene with $\ce{Me}$ on position 1 and $\ce{OMe}$ on position 2 goes to benzene with $\ce{Me}$ on 1 and $\ce{OH}$ on 2 by reaction with concentrated $\...
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1answer
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Litmus paper - turning red, blue and even bleached

I have blue litmus paper, and if I put it in an acid it turns red. I also have red litmus paper, and if I put it in a base, it turns blue. I know the question about litmus was asked and answered and I ...
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Reaction mechanism of combustion of hydrogen

After a discussion about the usefulness of hydrogen fuel for cars with a friend of mine, I wondered what the reaction mechanism for combustion of $\ce{H2}$ was. I only study (well almost) organic ...
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1answer
62 views

Mechanism of burning of hydrogen [duplicate]

So I was curious regarding a simple chemical equation : $$\ce{2 H2 + O2 -> 2 H2O}$$ You add heat to the system (i.e fire) and you get water vapor. I'm curious of understanding the mechanism, ...
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1answer
71 views

Preparation of sulfonyl chlorydes and mechanism of preparation of tosyl chloride

After searching about the preparation of sulfonyl chlorides, I couldn't find much. I found that for preparation of tosyl chloride, chlorosulfonic acid can be used, as in: Can chlorosulfonic acid be ...
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Whether a combination reaction goes to completion

There is a sentence in my textbook: When a combination reaction results in a gas that is allowed to be released, a precipitate that drops to the bottom of the container, or a nonionizing ...
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2answers
2k views

Ring expansion from a given cyclic carbocation

How will the cyclobutane ring behave in the case of cyclobutylmethylium (cyclobutylmethyl cation)? I initially thought there would be ring expansion to a five membered ring so that there may be less ...
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1answer
75 views

Distribution of polymer lengths

Suppose we have a chemical reaction where a linear chain can form (reversibly) from building blocks (e.g. atoms or molecules): $$\ce{X_$i$ + X_$k$ <=>[$k_\mathrm{fwd}$][$k_\mathrm{rev}$] X_$i$...
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869 views

Reaction of alkyl halides with strong unhindered bases

Please look at the image on this website: http://www.physicsforums.com/showthread.php?t=765853 For (b) and (c), what the solution manual says makes no sense to me. You're reacting a primary alkyl ...
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1answer
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Product of Friedel-Crafts cyclisation of (3-methylpent-4-en-1-yl)benzene

My proposed mechanism and final product is: But the book says the answer is: I know that a 6 membered ring is more stable than a 5 membered ring so I made the product with the 6 membered ring (...
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468 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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1answer
227 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 ...
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What reaction makes sodium silicate harden in CO2

I have looked all over the web, and I can only find information stating that it does happen. I don't doubt that I just can't figure out what is happening. Some sources state that an acid can cause the ...
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Where can I find equilibrium constants for a specific reaction? [duplicate]

I'm doing a project on the production of dap fertilizer, but I can not find a database with kinetics constants(reaction rate constant.) It's based on TVA Process for production of granular diammonium ...
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1answer
203 views

Mechanism of Fritsch–Buttenberg–Wiechell rearrangement

The following reaction was given, which uses potassium t-butoxide. The solution to this problem was given as follows: Step 1 is the attack of strong base, t-butoxide, on the vinyl proton. Step 2 ...
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1answer
27 views

When will acid-base reactions occur before substitution reaction

For example, given the reaction below: The substrate is secondary, the solvent is aprotic and it is to react with a strong bulky base. From this, I assumed that the reaction would be $\ce{E2}$. ...
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72 views

Why does the following “Battery” experiment work?

I did the following experiment: Experimental setup: Two electrodes (one made out of Iron,the other made out of Copper) are put into a (bluish) Copper(ii) sulfate lotion. Then, one connect a ...
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1answer
62 views

Regarding common preservatives and their effect

If someone has an average of 1 litre of Coke or Pepsi a day, would this form too much benzene oxide in the person's body or stomach and eventually effect part of their genetics?
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1answer
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How does hyperconjugation explain stability of partial positive charges?

Recently I was reading this answer to the question Why does boron add to the less substituted carbon in the hydroboration of an alkene?. See the transition state given in the above answer, and the ...
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1answer
2k views

Curly arrow mechanism for reaction between sodium borohydride and water?

I was asked to compare the reaction between sodium hydride and water and sodium borohydride and water. I know that the former acts more violently than the latter, but apparently, I must use a curly ...
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1answer
927 views

Neighbouring group participation with and without retention of configuration in nucleophilic substitution of 2,6-dichloro-9-thiabicyclo[3.3.1]nonane

Treatment of the dichloride A under the conditions indicated gives B with retention of configuration, while treatment of dichloride C gives D with inversion of configuration. I am having ...
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Does a non-chiral substrate (2-bromo-2-methylpropane) also form two products via an SN1 mechanism?

If I have an alkyl halide, in which its tertiary carbon is non-chiral (for example 2-bromobutane), which reacts via an SN1 mechanism does it also produce 2 products? I am asking because I know that ...
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2answers
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What is the mechanism of the Clemmensen reduction?

I have learned that we can reduce a ketone to an alkane using the Clemmensen reduction, where we treat the ketone with amalgamated zinc in the presence of $\ce{HCl}$. My book didn't mention the ...
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Haloform reaction with limited bromine

We were asked the reaction between 1 mole acetone and 1 mole $\ce{Br2}$ in basic medium. Since only a limited amount of bromine was given I got the final answer as 1-bromopropan-2-one (mono bromo ...
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1answer
588 views

Methyl Orange Indicator-Reason for small amount of NaOH [closed]

I used methyl orange as my indicator to titrate a weak acid: At first, I added 3 drops of methyl orange to a solution of the weak acid, $\ce{CH3COOH}$, and the solution turned red. Then, after ...
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2answers
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Mechanism of a cyclization reaction - why does an enol ether form?

I was asked to predict compound A from the follwing organic scheme: Looking at the formation of A, my prediction was that since TsOH is a strong acid, it would dehydrate the alcohols (like sulfuric ...
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1answer
2k views

Carbocation rearrangement with expansion of five-membered ring?

I am confused with this particular problem. I began the problem with a mechanism as following. In the beginning $\ce{H+} $ protonates the alcohol and leaves as $\ce{H_2O}$. Then everything is about ...
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23 views

Why does the reaction with copper and nitric acid change with concentration? [duplicate]

Depending on the concentration of nitric acid, copper undergoes two distinct reactions. For dilute concentrations of nitric acid, the reaction is $$3\text{Cu}+8\text{HNO}_3\rightarrow 3\text{Cu(NO}_3\...
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Reaction Mechanism with a Rate Determining Step

Just a quick question on how to deal with multiple intermediaries in a proposed reaction mechanism. Here is the overall reaction: $$\ce{I-(aq) + OCl-(aq) -> IO-(aq) + Cl-(aq)}$$ Here is the ...
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First order reaction

I am little bit confuse about relating the half life time period of a first order reaction something like $$\ce{2A -> B + C}$$ Here the rate of reaction will be half of the rate at which $\ce{A}$ ...
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3answers
739 views

Reaction of NaOD/D2O with semicarbazone

I managed to solve the question till D but I'm stuck at the last reaction. I tried to find its solution and the source suggest it as
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1answer
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Why do alpha-hydroxy ketones respond positively to Tollens', Fehling's, Benedict's, Schiff's and HgCl2 tests?

I learnt from a certain textbook that aldehydes and formic acid respond positively to Tollens', Fehling's, Benedict's, Schiff's and HgCl2 tests. However, in another textbook I read that even alpha-...
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3answers
587 views

Simple practical, non-toxic, non-flammable reaction for slow release of CO2

Someone I know (not me) has recently had problems with bed bugs. I have advised him his best bet is to (1) Buy a kick-ass steam cleaner and nuke the brutes from orbit, (2) get a professional pest ...
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2answers
117 views

reaction mechanisms of peroxides

Task: Explain the reaction mechanism of 1,4-Dioxane in terms of how you get peroxides. Start here with the autoxidation with one radical X. My explanation: in the first step 1,4 Dioxan reacts with ...
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1answer
224 views

What will be the order of acidity in the following compounds? [closed]

What will be the order of acidity in the following compounds ? From My point of view it should be 3>1>2>4. But the answer given is 3>2>1>4. Can anyone explain how ?
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389 views

Reaction of ketones with sodium amide

Find the product of the reaction of dimethyl ketone i.e. $\ce{CH3C(O)CH3}$ with $\ce{NaNH2}.$ Should I do nucleophilic addition and form the product in the picture?
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How to chelate magnesium oxide and l-lysine [closed]

Given magnesium oxide and l-lysine dissolved in water. What needs to happen so that both form a chelate inside the solution.
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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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3answers
7k views

Selective nitro reduction of poly nitro compounds

Is there any way through which I could selectively reduce one $\ce{NO2}$ group from a dinitro- or trinitro- compound to an amine. I was reading Solomons and Frhyle and it says that m-dinitrobenzene ...
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57 views

Why doesn't solvent form the major product in SN1 reactions?

If in a reaction SN1 pathway is followed then after the formation of carbocation the reagent or the solvent molecule can attack to form the product. As the number of solvent molecules are ...
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1answer
40 views

Rate expression for the final product [closed]

Let's say we have: $$ \begin{align} \ce{A &-> B}&\quad&\text{(fast equilibrium)}\label{rxn:1}\tag{1}\\ \ce{2 B + C &-> D}&\quad&\text{(slow)}\label{rxn:2}\tag{2}\\ \...