The synthesis of phenylalanine from benzyl chloride and ammonia can be achieved through a two-step process. The first step involves the formation of benzylamine, and the second step involves the Strecker synthesis to obtain phenylalanine.Step 1: Formation of BenzylamineBenzyl chloride C6H5CH2Cl reacts with ammonia NH3 to form benzylamine C6H5CH2NH2 and hydrochloric acid HCl as a byproduct. The reaction can be represented as follows:C6H5CH2Cl + NH3 C6H5CH2NH2 + HClOptimal conditions for this reaction include an excess of ammonia and a polar aprotic solvent like dimethylformamide DMF or dimethyl sulfoxide DMSO . The reaction should be carried out at low temperatures 0-5C to minimize side reactions and improve the yield of benzylamine.Step 2: Strecker SynthesisThe Strecker synthesis involves the reaction of benzylamine with an aldehyde or ketone, followed by the addition of hydrogen cyanide HCN and hydrolysis to obtain the desired amino acid. In the case of phenylalanine synthesis, benzylamine reacts with acetaldehyde CH3CHO in the presence of HCN, followed by hydrolysis to yield phenylalanine. The reactions can be represented as follows:C6H5CH2NH2 + CH3CHO + HCN C6H5CH2NHCH CH3 CNC6H5CH2NHCH CH3 CN + 2H2O C6H5CH2NHCH CH3 COOH + NH3Optimal conditions for the Strecker synthesis include the use of a polar solvent like water or an alcohol, low temperatures 0-5C , and a slow addition of HCN to the reaction mixture. The hydrolysis step can be carried out at room temperature or slightly elevated temperatures 40-50C using an acid or base catalyst.Challenges and drawbacks of this synthetic pathway:1. Handling of hazardous chemicals: The use of HCN in the Strecker synthesis is hazardous due to its high toxicity. Proper safety measures and precautions must be taken while handling HCN.2. Side reactions: The formation of benzylamine from benzyl chloride and ammonia can lead to side reactions, such as the formation of dibenzylamine and tribenzylamine, which can reduce the yield of the desired product.3. Incomplete conversion: In the Strecker synthesis, the formation of the nitrile intermediate may not be complete, leading to a lower yield of phenylalanine.4. Chiral center: Phenylalanine has a chiral center, and the Strecker synthesis produces a racemic mixture of both L- and D-phenylalanine. Separation of the enantiomers may be required for specific applications, which can be challenging and time-consuming.5. Environmental concerns: The use of polar aprotic solvents like DMF and DMSO can raise environmental concerns due to their toxicity and persistence in the environment. Alternative, greener solvents should be considered if possible.