We used sodium dichromate in sulfuric acid to oxidize borneol to camphor. Suppose you needed to prepare benzaldehyde from benzyl alcohol. Would the sodium dichromate be the best choice for this oxidation or are there better choices? Explain.

To determine whether sodium dichromate is the best choice for oxidizing benzyl alcohol to benzaldehyde, we need to consider a few factors. Oxygenation reactions like these are influenced by several variables, including selectivity, yield, and safety.

Sodium dichromate is a powerful oxidizing agent commonly used in organic chemistry for various oxidative transformations. However, it has certain drawbacks that might make it less suitable for oxidizing benzyl alcohol to benzaldehyde:

1. Selectivity: Sodium dichromate is known to be a relatively non-selective oxidizing agent, meaning it can oxidize multiple functional groups present in the starting compound. This lack of selectivity could lead to the formation of undesired side products, reducing the overall yield of benzaldehyde.

2. Yield: Sodium dichromate is effective for many oxidation reactions, but it might not provide the highest possible yield for the oxidation of benzyl alcohol to benzaldehyde. There are alternative reagents that can offer higher selectivity and yield, ultimately resulting in a more efficient conversion.

Based on these considerations, there are better choices for oxidizing benzyl alcohol to benzaldehyde. One commonly used reagent is chromic acid (CrO3/H2SO4). Chromic acid can be prepared by dissolving chromium trioxide (CrO3) in concentrated sulfuric acid (H2SO4). It is known to provide higher selectivity and yield compared to sodium dichromate.

Another alternative is using the PCC (pyridinium chlorochromate) reagent. PCC is a milder oxidizing agent that selectively oxidizes primary alcohols to aldehydes without further oxidation to carboxylic acids. This selectivity makes PCC an excellent choice for converting benzyl alcohol to benzaldehyde.

In summary, while sodium dichromate is a powerful oxidizing agent, its lack of selectivity and potential for side reactions make it less ideal for the oxidation of benzyl alcohol to benzaldehyde. Instead, reagents like chromic acid or PCC offer better selectivity and yield for this specific transformation.