The synthesis of phenylalanine from benzyl chloride and ammonia typically involves two main steps: the formation of N-benzyl amine and the subsequent reaction with phenylacetyl chloride to produce phenylalanine. For the first step, the optimum molar ratio of benzyl chloride to ammonia is 1:1. This is because the reaction between benzyl chloride and ammonia is a nucleophilic substitution reaction, where one molecule of benzyl chloride reacts with one molecule of ammonia to form N-benzyl amine and hydrochloric acid HCl . However, in practice, an excess of ammonia is often used to drive the reaction to completion and minimize the formation of by-products. This excess can be in the range of 1.5 to 2 times the stoichiometric amount of ammonia. The use of excess ammonia can improve the yield of N-benzyl amine, but it may also lead to the formation of unwanted side products.For the second step, the molar ratio of N-benzyl amine to phenylacetyl chloride is also 1:1, as one molecule of each reactant is required to form one molecule of phenylalanine. However, similar to the first step, an excess of one of the reactants usually N-benzyl amine can be used to drive the reaction to completion and improve the overall yield of phenylalanine.In summary, the optimum molar ratio of benzyl chloride to ammonia for the production of phenylalanine using chemical synthesis is 1:1, but an excess of ammonia is often used to improve the yield of the reaction. The actual yield of phenylalanine will depend on various factors, such as reaction conditions, purity of reactants, and the efficiency of the purification process.