in gas chromatography, why do E1 and E2 give different peaks (areas) though it's the same compound??
For example, for 1-butene, the percent composition is low in E1 but very high in E2.
so it is because acidic and basic conditions are used...but I'm still unsure how that gives different product ratios.
I think you need to explain more about what you have done/are doing.
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 and I am not sure how and why it does.
In gas chromatography, the separation of compounds is based on their partitioning between a stationary phase and a mobile phase. The stationary phase is a solid or a liquid coated on the inside of the column, while the mobile phase is a carrier gas that carries the sample through the column.
The primary reason why E1 and E2 give different peaks and areas for the same compound, like 1-butene, is due to the differences in the affinity of the compound for the stationary phase and the retention time in the column.
Here's an explanation of how these factors contribute to the differences in peaks and areas in E1 and E2:
1. Stationary phase: The stationary phase can vary between different columns used in gas chromatography. It could be polar, non-polar, or have different functional groups. The affinity of the compound towards the stationary phase is strongly influenced by its chemical structure and polarity. Different columns may have different selectivities towards specific compounds or functional groups.
2. Retention time: The retention time of a compound refers to the time it takes for the compound to elute from the gas chromatography column. It is influenced by the degree of interaction between the compound and the stationary phase. Compounds that have a stronger affinity for the stationary phase will elute later, resulting in a longer retention time.
Now, coming back to the example of 1-butene in E1 and E2:
E1 and E2 might use different columns with different stationary phases, thus leading to differences in their separation. It's quite possible that the stationary phase in E2 has a higher affinity for 1-butene compared to the stationary phase in E1. This results in a longer retention time and a higher peak area in E2.
Additionally, the percent composition of 1-butene could be influenced by other factors such as differences in sample preparation, injection technique, column temperature, or carrier gas flow rate between E1 and E2.
To further understand the specific reasons behind the differences in peaks and areas, it would be helpful to know more details about the exact setup and conditions used in both E1 and E2.