VCL 10.4 Carbonyl Reduction issues

Organic Chemistry --> Carbonyl Additions --> VCL 10.4 Reduction of Carbonyls (benzaldehyde reduction with sodium borohydride recommended)

This reaction appears to work with water as the original solvent. It even forms two layers when aqueous HCl is added for the workup!

In the proton NMR of benzyl alcohol, the apparent signal intensities (height) do not match the table on the bottom. Why is signal height given in the table (which should be apparent from the spectrum) and not integration (useful information for NMR interpretation)?

The MS spectrum of benzyl alcohol does not have the molecular mass peak (108 g/mol) even though the SDBS MS spectrum has prominent signals at 108 & 107 m/z.

Hi jbfriesen,

You are correct about the sep funnel extraction glitch and the missing peaks in the MS. They are both on our list of changes to be made.

The heights provided in the proton NMR are the relative areas of each peak. They can be compared to each other to provide the correct proton ratios. These actual values of the areas are randomized each time a spectrum is taken, but the ratio always remains the same. For example, the attached spectrum for benzyl alcohol has a ratio (for peaks 1/2/3) of 257/102/51 or ~ 5/2/1, corresponding to the 5 aromatic protons, the 2 methylene protons, and the alcohol proton.

Kelsey