To synthesize phenylalanine from benzyl chloride and ammonia, you can follow the Strecker synthesis, which involves three main steps: nitrile formation, nitrile hydrolysis, and enantiomeric resolution. Here are the key reaction parameters and conditions that must be carefully controlled to achieve high yields and purity:1. Nitrile formation:React benzyl chloride with sodium cyanide NaCN to form benzyl nitrile. This reaction is an SN2 nucleophilic substitution, and the key parameters to control are temperature, concentration, and solvent. The reaction should be carried out in a polar aprotic solvent, such as dimethyl sulfoxide DMSO or acetonitrile MeCN , at a temperature between 0-25C to minimize side reactions. The concentration of the reactants should be kept low to avoid the formation of by-products.2. Nitrile hydrolysis:Benzyl nitrile is then hydrolyzed to form -aminocinnamic acid. This step involves the reaction of benzyl nitrile with ammonia NH3 and water H2O under acidic conditions. The key parameters to control in this step are temperature, pH, and the ratio of ammonia to nitrile. The reaction should be carried out at a temperature between 80-100C and a pH of 4-6 to ensure complete hydrolysis. The molar ratio of ammonia to nitrile should be at least 3:1 to ensure a high yield of -aminocinnamic acid.3. Enantiomeric resolution:-Aminocinnamic acid is a racemic mixture of D- and L-phenylalanine. To obtain pure L-phenylalanine, enantiomeric resolution is required. This can be achieved by crystallization with an optically active resolving agent, such as L-tartaric acid or L-phenylalanine methyl ester hydrochloride. The key parameters to control in this step are the concentration of the resolving agent, temperature, and solvent. The reaction should be carried out in a solvent that allows for the selective crystallization of the desired enantiomer, such as ethanol or methanol, at a temperature between 0-25C. The concentration of the resolving agent should be carefully adjusted to ensure the formation of diastereomeric salts with the desired enantiomer.By carefully controlling these reaction parameters and conditions, it is possible to synthesize phenylalanine from benzyl chloride and ammonia with high yields and purity.