Is Vanillin Formation Likely Based on IR Spectrum Analysis?

[jsmith613]

Homework Statement

I have attached the question and necessary infromation

Homework Equations

The Attempt at a Solution

so here's what I would say

"Unlikely as the peaks in the IR spec are very similar, no additional peaks have shown"

BUT THE MARK SCHEME SAYS

Vanillin IS likely to have formed;
as the IR spectrum shows absorption for C=O;
at about 1740-1720;
this is ABSENT IN THE IR SPEC of 2-methoxyphenol


BUT IT CLEARLY IS NOT, the PEAK IS CLEARLY THERE IN BOTH SPECTRA
What are they talking about?

 

[TeethWhitener]

C=O peaks are very strong, and the difference between the spectra is that the peak at 1740 is much stronger in the product spectrum than in the reagent spectrum.