Recovery method of zopiclone resolving agent D-(+)-malic acid

The invention discloses a recovery method of zopiclone resolving agent D-(+)-malic acid. The recovery method comprises the following steps: adding acid into a mother liquor obtained by resolving zopiclone by using D-(+)-malic acid as a resolving agent to regulate the pH value to 1-3; adding ammonium sulfate to obtain saturated solution of ammonium sulfate; extracting by ethyl acetate to obtain an extract liquor; concentrating the extract liquor to 1/10-1/8 of the extract liquor; and carrying out cooling crystallization and filtration to obtain D-(+)-malic acid. According to the method, the problem that D-(+)-malic acid is large in consumption and high in cost when being used as a resolving agent, and the recycling of the resources is realized. Through resolution verifying, the obtained product is high in optical purity, the recovery rate is up to 90%, the energy is saved, the production cost is low, and benefit is brought to the environment protection and large-scale industrial production.