The reaction of phenol with benzoyl chloride to give phenyl benzoate is known as :

The question asks about the name of the reaction where phenol reacts with benzoyl chloride to form phenyl benzoate.

First, let's recall the reaction: phenol (C6H5OH) reacts with benzoyl chloride (C6H5COCl) to produce phenyl benzoate (C6H5COOC6H5). The reaction can be written as:

$$ C_{6}H_{5}OH + C_{6}H_{5}COCl -> C_{6}H_{5}COOC_{6}H_{5} + HCl $$

This reaction typically requires a base, such as sodium hydroxide (NaOH), to neutralize the hydrochloric acid (HCl) produced and drive the reaction forward. The overall process is known as benzoylation.

Now, let's examine the options:

Option A: Claisen reaction. This refers to the Claisen condensation, which involves the reaction between two ester molecules in the presence of a strong base to form a β-keto ester. For example, ethyl acetate reacts to form acetoacetic ester. It does not involve phenol or benzoyl chloride, so this is incorrect.

Option B: Schotten-Baumann reaction. This reaction specifically describes the benzoylation of compounds with active hydrogen atoms (like phenols or amines) using benzoyl chloride in the presence of an aqueous base (such as NaOH). The base helps by neutralizing the acid formed and making the nucleophile (phenol) more reactive. This matches the given reaction perfectly, as phenol reacts with benzoyl chloride under Schotten-Baumann conditions to yield phenyl benzoate.

Option C: Reimer-Tiemann reaction. This reaction involves phenol reacting with chloroform (CHCl3) in the presence of a strong base (like NaOH) to produce ortho-hydroxybenzaldehyde (salicylaldehyde). It introduces an aldehyde group (-CHO) at the ortho position. Since benzoyl chloride is not used, this option is incorrect.

Option D: Gatterman-Koch reaction. This reaction is used to introduce an aldehyde group (-CHO) into an aromatic ring using carbon monoxide (CO) and hydrogen chloride (HCl) in the presence of a catalyst (like AlCl3 and CuCl). It is typically applied to benzene or its derivatives, not phenol, and does not involve benzoyl chloride. Hence, this is incorrect.

Therefore, the reaction of phenol with benzoyl chloride to form phenyl benzoate is known as the Schotten-Baumann reaction.

Hence, the correct answer is Option B.