On acetylation with acetic anhydride, glucose gives

Options

A. Diacetate
B. Hexa-acetate
C. Pentacetate
D. Tetra-acetate

Answer

To solve the question "On acetylation with acetic anhydride, glucose gives," we need to understand the process of acetylation and how it applies to glucose. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand the Structure of Glucose
Glucose is a monosaccharide with the molecular formula C₆H₁₂O₆. It contains five hydroxyl (–OH) groups attached to its carbon atoms. The structure of glucose can be represented as follows:

- The carbon skeleton consists of six carbon atoms.
- Each of the five hydroxyl groups is attached to the carbon atoms, and one carbon is part of an aldehyde group (–CHO).

### Step 2: Identify Acetic Anhydride
Acetic anhydride (CH₃CO)₂O is a reagent used for acetylation. It has the following structure:

- Two acetyl groups (CH₃CO) connected by an oxygen atom.

### Step 3: Mechanism of Acetylation
During acetylation, the hydroxyl groups of glucose react with acetic anhydride. The hydroxyl oxygen acts as a nucleophile and attacks the electrophilic carbonyl carbon of acetic anhydride. This results in the formation of an ester bond and the release of acetic acid as a byproduct.

### Step 4: Reaction of Glucose with Acetic Anhydride
Since glucose has five hydroxyl groups, each of these –OH groups will react with acetic anhydride. The reaction can be summarized as follows:

- Each hydroxyl group (–OH) is replaced by an acetyl group (–OCOCH₃).
- This results in the formation of a compound known as glucose pentacetate, where all five hydroxyl groups are converted into acetate groups.

### Step 5: Final Product
The final product of the acetylation of glucose with acetic anhydride is called **glucose pentacetate**. The reaction can be summarized as:

\[ \text{Glucose} + 5 \text{(Acetic Anhydride)} \rightarrow \text{Glucose Pentacetate} + 5 \text{(Acetic Acid)} \]

### Conclusion
On acetylation with acetic anhydride, glucose gives **pentacetate** as the main product.

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