E1 Mechanism

Question 1

What is an E1 reaction?

Answer 1

The elimination reaction takes place by a stepwise mechanism involving intermediate carbocations
E stands for elimination and 1 stands for unimolecular

Question 2

What is the rate equation?

Answer 2

Rate= k[RX]

Question 3

What does the rate equation suggest about the reaction?

Answer 3

It suggests the rate only depends on HC and not on the base as the base is not involved in the rate equation

This means the reaction is bimolecular as only one reactant molecular is involved in the transition state

Question 4

Describe the process of the reaction

Answer 4

2 step reaction
1) CX bond breaks to form a carbocation and halide ion
This is the rate determining step which is by the rate only depends on HX
2) the base removes one of the hydrogens on the carbocation to form a new C=C bond

Question 5

Why does the E1 mechanism not need the HX to be in a particular position to react?

Answer 5

This is because the intermediate has a C-C bond which means the carbocation can freely rotation to align the sigma orbital of the CH bond with the empty p orbital
Overlap side on

Question 6

How does the number of alkyl groups affect the rate?

Answer 6

The greater the number of alkyl groups, the faster the rate of reaction
+I effect stabilised the positive carbon

Question 7

Why do tertiary HX react in E1 reactions whereas secondary and primary do not?

Answer 7

This because the methyl groups of the tertiary can stabilise the positive carbon of the carbocation whereas primary and secondary cannot stabilise it