Chemistery

Let's compare E1 and E2 in the following aspects: Base Substrate Solvent Leaving Group Kinetics Stereochemistry Rearrangements  Base E1: As the base abstracts the proton only after the carbocation intermediate is formed, it does not affect the rate of reaction, hence not important. E2: A strong base is indeed needed to promote the one-step reaction. Substrate E1: A more substituted substrate stabilizes the carbocation intermediate.  E2: A more substituted substrate forms a more substituted alkene.  Solvent E1: A polarizing solvent enhances the rate of ionization as it pulls the cation and anion apart.  E2: The transition state is less sensitive to the solvent as the transition state has its negative charge shared over the whole molecule.  Leaving Group Both reactions need a good leaving group.  Kinetics E1: The rate is only determined by the substrate as it is the only molecule that ionizes. E2: Both the substrate and the base aff...

Here is what is going on in an elimination reaction: base abstracts proton pi bond forms leaving group leaves  In E2, everything happens in one step ( concerted reaction again just as in SN2). Just like SN2, there is no intermediate formed and there is only one transition state (2 transition state for E1 and SN1). E2 Mechanism Base & Substrate Here, a strong base is required instead of a strong nucleophile because a proton is abstracted (not an electrophilic carbon atom being attacked). Note that a strong nucleophile is usually a strong base. If the substrate is a primary, SN2 may take place instead. Therefore, we want the substrate to be tertiary/ more substituted. This also has to do with the transition state and the alkene formed. In the transition state, a more substituted substrate is more stable, hence in a lower energy state. For the alkene formed, a more substituted alkene is the major product ( Zaitsev's rule ); when there is a choice of proton...

After introducing electrophile and nucleophile, let's talk about SN1 , SN2 , E1 and E2 . Let's see what they mean first: SN1: First-Order Nucleophilic Substitution SN2: Second-Order Nucleophilic Substitution E1: First-Order Elimination E2: Second-Order Elimination   So basically, these 4 types of reactions are categorized into   Nucleophilic Substitution and Elimination .  Nucleophilic Substitution means one thing is substituted by something else, which is a nucleophile (to make it nucleophilic) Elimination always form a double bond product because as something is eliminated, the remained  electrons form a double bond  The condition for each of these reactions are different (solvent, leaving group, reactant bulkiness, etc) and the ability to classify them is crucial. Here is a table summarized all we need to know about them.   source: www.pinstopin.com Our team at Chemistery uses NordVPN every day and we high...