The preparation of high-yield phenylalanine from benzyl chloride and ammonia can be achieved through a two-step process: the formation of N-benzylamine and the Strecker synthesis. Here are the optimal reaction conditions and steps for each stage:1. Formation of N-benzylamine:a. Reactants: Benzyl chloride C6H5CH2Cl and ammonia NH3 b. Solvent: Anhydrous ether or toluenec. Temperature: 0C to 5C cooling the reaction mixture is essential to prevent side reactions d. Procedure: Slowly add benzyl chloride to a solution of anhydrous ammonia in anhydrous ether or toluene under constant stirring. The reaction is exothermic, so it is crucial to maintain the temperature between 0C and 5C. After the addition is complete, stir the mixture for an additional 30 minutes to ensure complete reaction.e. Workup: Separate the organic phase and wash it with water to remove any unreacted ammonia. Dry the organic phase over anhydrous magnesium sulfate, filter, and evaporate the solvent to obtain N-benzylamine.2. Strecker synthesis:a. Reactants: N-benzylamine, hydrogen cyanide HCN , and an aldehyde or ketone R-CHO b. Solvent: Water or a mixture of water and an alcohol e.g., methanol or ethanol c. Temperature: Room temperature 20C to 25C d. Procedure: Add N-benzylamine to a solution of the aldehyde or ketone in the solvent. Then, slowly add hydrogen cyanide to the reaction mixture under constant stirring. The reaction mixture should be stirred for several hours to ensure complete reaction.e. Workup: Acidify the reaction mixture with a mineral acid e.g., hydrochloric acid to convert the intermediate imine into the corresponding -aminonitrile. Separate the organic phase and extract the aqueous phase with an organic solvent e.g., ethyl acetate . Combine the organic extracts, dry over anhydrous magnesium sulfate, filter, and evaporate the solvent to obtain the -aminonitrile.f. Hydrolysis: Hydrolyze the -aminonitrile by refluxing it in a solution of a mineral acid e.g., hydrochloric acid or a strong base e.g., sodium hydroxide in water. After the hydrolysis is complete, neutralize the reaction mixture and extract the phenylalanine using an organic solvent e.g., ethyl acetate . Dry the organic phase over anhydrous magnesium sulfate, filter, and evaporate the solvent to obtain the crude phenylalanine.g. Purification: Recrystallize the crude phenylalanine from a suitable solvent e.g., water or ethanol to obtain high-yield, pure phenylalanine.By following these steps and maintaining the optimal reaction conditions, you can successfully prepare high-yield phenylalanine from benzyl chloride and ammonia using chemical synthesis techniques.