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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83 views

What is the major product of the reaction of a geminal dibromide with silver nitrate? [closed]

$\ce{Ag+/H2O}$ is used for peroxide formation, then followed by hydrolysis to yield an alcohol. But in the question it is a geminal dihalide and I don't know if the mechanism follows through a ...
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1answer
47 views

What is the major product of the reaction between 4-chlorobut-1-ene?

When acetic acid looses hydrogen, an acetate ion is formed which attacks 4-chlorobut-1-ene, forming methyl butenoate. How does the cyclic structure form? Does the lone pair of oxygen attack the butene ...
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1answer
55 views

What happens to copper(II) hydroxide when it's heated? what's inside its decomposition?

So just wondering, copper(II) hydroxide undergoes thermal decomposition when it's heated. But isn't it a solid by itself too? Why does it turn into another solid and water all of a sudden? Can ...
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1answer
610 views

Why do disproportionation reactions take place?

I want to know what are the conditions when disproportionation reaction is feasible. Is it just because of stability factors or it has other dimensions to it. As an example: $$\ce{3HNO2 -> HNO3 + ...
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40 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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How does the inductive effect, explain the reactivity of tertiary alcohols with halogen acids?

The reactions of primary and secondary alcohols with halogen acids ($\ce{HX}$, where $\ce{X}$=halogen) require the presence of a catalyst, $\ce{ZnCl_2}$. With tertiary alcohols, the reaction is ...
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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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2answers
363 views

Kolmogorov backward equations in active biological systems

I am trying to understand the following equations from a paper by Wang et al. [1, p. 5 at the SI]: Michaelis–Menten Representation of the Kinesin Cycle We assumed that there is a strong ...
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3answers
181 views

Reaction mechanism of rearrangement

I am currently studying for my organic chemistry exam, but there is one problem I do not understand. Unfortunately, I do not have any solutions. See image for the problem. My first thought was the ...
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29 views

Difference between base-promoted and base-catalysed

Why is halogenation of ketones in base described as being "base-promoted" and not "base-catalysed"? If the reaction is not "catalyzed" then how is the base used up?
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471 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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Why do carbonyl compounds undergo nucleophilic and not electrophilic addition?

Why aldehydes and ketones undergo nucleophilic addition reactions and not electrophilic addition? Alkenes show electrophilic addition because of pi bond, which is also present in aldehydes and ...
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1answer
905 views

Mustard gas hydrolysis (at a very high rate)

Explain mustard gas hydrolysis at a very high rate: $\ce{Cl-CH2-CH2-S-CH2-CH2-Cl}$ I tried searching online but did not find this reaction anywhere. Can someone explain me the steps/mechanism of ...
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2answers
63 views

How would this reaction look like in a potential energy diagram? (SN1 Reaction)

My task is to explain, why molecule A reacts in a SN1-reaction faster than molecule B. (I would do this by comparing their potential energy diagrams) My idea is to have a closer look at the reaction ...
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57 views

Reduction of ester in presence of ketone group

As there is no ring expansion I'm assuming that a carbocation should not form at ester carbon as it leads to ring expansion. But is there any an exception to it? Also the hint provided along with this ...
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2answers
119 views

Potassium carbonate vs. Potassium hydroxide in Wood Ash

I'm trying to get more concrete information about the chemical process of creating soap from wood ash. What I’m confused about: Many soap-making materials say that you create potassium hydroxide ...
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Reaction of alcohols with PCl5 and PCl3

The reaction of alcohols $\ce{ ROH }$ with $\ce{ PCl5 }$ and $\ce{ PCl3 }$ yields an alkyl halide $\ce{RCl}.$ With $\ce{ PCl5 }$, the reaction is quite simple leading to the formation of $\ce{ RCl }$ ...
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How to make an aluminumoxide coating on an electrode?

The Questions is above. I am not a chemist but that is what I know: Aluminum has an Oxide Layer normally Aluminum-Oxide Layer can be broken down with NaOH Zink coatings are done by galvanic coating ...
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87 views

Which of the following statements is true if HI is formed in the following reaction?

Which of the following statements is true if HI is formed in the following reaction? $$\ce{H2(g) + I2(g) -> 2HI(g)}$$ a. There are no collisions between the reactants in the reaction. ...
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77 views

Polar Protic and Aprotic Solvents

I know $\mathrm{S_N2}$ is favored polar aprotic solvents, which means that they may have hydrogens on them somewhere, but they lack $\ce{O-H}$ or $\ce{N-H}$ bonds, and therefore cannot hydrogen bond ...
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2answers
529 views

Coupling of silyl imine and aldehyde

LDA is a strong base and probably deprotonates somewhere which I'm not sure about. It I would to make a guess it would probably be beta to the imine. This is following by nucleophilic attack of the ...
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What is the mechanism of the reaction of ethyl prop-2-ynoate to ethyl (2Z)-2,3-dibromoprop-2-enoate?

It's really weird for the product is 99% Z-comformation? Please tell me why? This reaction can be found in scifinder.
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Mechanism of DPD (N,N-diethyl-p-phenylenediamine) reaction with free chlorine

NOTE: As I've been finding new informations about the question, I've been editing the question to keep it up to date. If some comment doesn't make sense just check the Edit History. DPD (N,N-diethyl-...
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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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intuitive explanation of Wegscheider condition and its violation

The Wegscheider condition restricts the values that rate constants in a set of chemical reactions can take on. can someone please explain intuitively why the condition has to be true, and give a ...
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why lithium is less reactive than sodium? [duplicate]

Lithium lies above sodium in a group and is also smaller in size. According to periodic trend reactivity decreases from left to right in period and down the group.
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1answer
34 views

Synthesis for turning synephrenine into N-methylphenethylamine

I am trying to devise a synthesis to change synephrine (4-[1-hydroxy-2-(methylamino)ethyl]phenol) into N-methylphenethylamine. I was figuring that I could remove the hydroxyl group attached to the ...
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30 views

Aldol Reaction on an intermediate

I was given the following reaction to prove a mechanism for: and I managed to prove the first step with ease. The second step, forming the "base-catalysed aldol" is the part that's rather confusing ...
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1answer
71 views

Grignard alkene on a carbonyl

I was given the following mechanism to prove today post-lecture: and my attempt is given below. Now, when the negative charge on the alkene attacks the carbonyl, the electrons are pushed onto the ...
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2answers
59 views

DNA-Sequencing (detection of the change of pH-value) after emulsion PCR

I have troubles with understanding the exact order of the steps for DNA-sequencing after the Emulsion PCR (EmPCR). The EmPCR fills each bead with the same DNA strand (copies it $n$ times, till the ...
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Book Recommendations for Inorganic Chemistry Mechanisms [duplicate]

I am looking for a book which has details or basics to reaction mechanisms for inorganic chemistry for highschool level(preferably) or maybe undergrad level. Basically I am looking for a book which ...
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2answers
104 views

How to dissolve calcium sulfate fast?

I would like to dissolve $\ce{CaSO4}$ in a hardened condition (e.g. gypsum board) as fast as possible. I have seen in posts about $\ce{CaSO3}$ that vinegar and sulfamic acid are able to dissolve it. ...
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1answer
51 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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1answer
65 views

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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2answers
676 views

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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2answers
122 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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0answers
49 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
577 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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1answer
71 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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2answers
58 views

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
13k views

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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3answers
3k views

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
61 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, ...
2
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1answer
55 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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1answer
17 views

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
1k 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 ...
3
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1answer
70 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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1answer
841 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 ...