Synthesis process of neotame

The invention discloses a synthesis process of neotame. The synthesis process comprises the following steps: adding aspartame into a reaction container, performing water-bath heating to 33-35 DEG C, further adding 3,3-dimethyl butyraldehyde, heating to 30-60 DEG C, performing heat preservation reaction for 55-70 minutes, then adding a catalyst at the temperature, and introducing hydrogen for reacting for 14-16 hours; after the end of the reaction, filtering the catalyst to get filtrate, further washing the catalyst with an appropriate amount of methanol, merging the filtrate and washing liquid, performing vacuum distillation at the temperature of 40-50 DEG C, distilling obtained solids, further adding water, cooling, crystallizing, filtering at the temperature of less than 5 DEG C, drying and crushing to get a crude product; and adding 15-40% ethanol into the crude product, drying and crushing to get a final neotame finished product. According to the synthesis process of the neotame, the yields of the crude p