E2 reactions | Substitution and elimination reactions | Organic chemistry | Khan Academy

E2 Elimination Reactions. Created by Sal Khan.

Organic Chemistry on Khan Academy: Carbon can form covalent bonds with itself and other elements to create a mind-boggling array of structures. In organic chemistry, we will learn about the reactions chemists use to synthesize crazy carbon based structures, as well as the analytical methods to characterize them. We will also think about how those reactions are occurring on a molecular level with reaction mechanisms. Simply put, organic chemistry is like building with molecular Legos. Let's make some beautiful organic molecules!

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[nataliabrand]

Thanks! I learned more with you in 4 videos then in 1 year at Rutgers lol

[pontos]

2 important things Sal forgot to mention. E2 reactions occur at very high temperatures, and they need a bulky base to prevent an SN2 reaction from occurring.

[benwilliams]

Sal, you're still the undisputed master at explaining Organic Chemistry. Great video. Really wish you taught Orgo in every Khan Academy video.

[Thinobard]

This is wrong.  For an E2 reaction to take place the geometry must be anti periplanar.  The alkyl halide must be in perspective formula to be a correct mechanism.

[ilickcatnip]

His voice is so good, you just can't do anything but pay attention.

[cole]

Will you be my Organic Professor! You are so much better than the one I have currently!

[Oodstech]

The repetition might not be pleasant, however it IS useful.

[lilangel]

i thought for E2 reactions the leaving H and Cl had to be antiperiplanar???

[DicedPeas]

@antonyfl

Since the base is so strong, E2 will still occur here. Polar protic solvents CAN be used for E2/SN2 under the right conditions. Since polar protic solvents are much cheaper, this is actually how SN2/E2 is carried out industrially.

[DopeFreshFitness]

No, Na+ and OCH3- where both free ions in the solution, "replace" usually suggests a causal relationship, and that H certain didn't cause the reaction to happen, rather OCH3- did.

[dishonesttAbe]

You should cover quantum mechanics after the chemistry is finished. You make difficult math concepts easy to understand so I imagine you can do QM very well.

[Dccole]

Strength of base and nucleophile take priority over solvent when determining which type of reaction it is.

[ShimmyMD]

@dalcde Yup it does. We just leave it out bc they're not organic products.

[danielafernandez]

The ch3o attacks that specific hydrogen because, according to zaitsev's rule, the hydrogen tnat should leave is the one bonded to the less hydrogenated carbon

[MsHellogoodbyee]

I also believe this would be best in an E1 reaction. The carbocation would be stable as tertiary and it's a polar protic solvent!

[dovelygodess]

Yay Khan Academy! To the rescue again!

[antonyfl]

Quick note Sal: This reaction isn't the best to show an E2 mechanism because the solvent is CH3OH, a polar protic solvent, which actually would favour SN1/E1 . I think a better solvent for this example would be DMSO

[BlueDeath]

These videos are great supplemental learning tools!

[FindingCreatures]

The hydrogen that is taken in an elimination reaction is anticoplanar

[soulmatesr]

how can we know is the given base is strong or weak? is there any priority order for it? plz clear my confusion....