in gas chromatography, why do E1 and E2 give different peaks (areas) though it's the same compound??
dehydration of a secondary alcohol proceeds readily with the presence of strong acid and proceeds with E1 mechanisms. Removing product from chemical system at equilibrium shifts the equilibrium in the direction favoring the formation of the products.
I carried out a dehydration in reaction tube connected to a gas collector so that product will continously escape out of reaction mixture as it is formed. The collected gaseous product was anaylzed using gas chromatography which show peaks. With the relative area of peaks, we are able to calculate percentage composition of product mixture.
for the second part, I proceeded with the base-induced dehybromination reaction which goes through E2 mechanism.
1-butene was one of the compounds in the mixture and the peak was low (percent composition was low) but in E1, the peak (percent composition) was very high in E2.
So depending on the mechanism, it produces different amounts of the products since in one we're using acid and the other we're using a base and I am not sure how and why it gives different amounts.
In gas chromatography, the peaks and areas observed on the chromatogram correspond to the different compounds present in the mixture being analyzed. These peaks are a result of the separation of the components based on their physical and chemical properties.
When comparing E1 and E2 mechanisms for the dehydration of a secondary alcohol, it's important to understand the differences between the two processes.
E1 mechanism involves the formation of a carbocation intermediate, followed by the elimination of a proton to generate the alkene. This mechanism is favored in the presence of strong acids. The E1 reaction usually occurs via a unimolecular process, which means that the rate-determining step involves only one molecule.
On the other hand, E2 mechanism involves a concerted reaction where the proton and leaving group are eliminated simultaneously. This mechanism is favored in the presence of strong bases. The E2 reaction usually occurs via a bimolecular process, which means that the rate-determining step involves two molecules.
Now, when you carried out the dehydration reaction, you used a gas collector to continuously remove the gaseous product as it was formed. By collecting the gaseous product and analyzing it using gas chromatography, you were able to obtain peaks that corresponded to the different compounds in the mixture.
The difference in the peaks you observed for the compound 1-butene in E1 and E2 mechanisms can be attributed to the different reaction conditions and mechanisms involved.
In the E1 mechanism, the presence of strong acid promotes the formation of the carbocation intermediate, which can lead to a higher yield of 1-butene. This may result in a higher peak and percentage composition of 1-butene in the gas chromatogram.
On the other hand, in the E2 mechanism, a strong base is used, and the reaction occurs via a concerted process without the formation of a carbocation intermediate. The efficiency of the E2 reaction may depend on factors such as the strength and concentration of the base used. If the conditions are not optimal, the yield of 1-butene may be lower, resulting in a lower peak and percentage composition on the gas chromatogram.
To summarize, the difference in peaks (areas) observed for 1-butene in E1 and E2 mechanisms in gas chromatography can be attributed to the different reaction conditions (acid vs. base) and mechanisms involved. The choice of reaction conditions and mechanism can influence the efficiency and yield of the desired product, thus leading to different amounts of the products being produced.