Method for extracting linoleic acid from cotton seeds

The invention discloses a method for extracting linoleic acid from cotton seeds. The method comprises the following steps: (1) leaching the cotton seeds by an ethanol-liquefied propane mixed solvent to obtain an extracting solution, wherein the leaching temperature is 50-60 DEG C, and the leaching time is 1-1.5 hours; (2) preparing a urea-ethanol solution at the temperature of 70 DEG C; (3) at thetemperature of 70 DEG C, adding the urea-ethanol solution in the extracting solution, refluxing and stirring for 1 hour, stopping heating after a mixture becomes clear and transparent, continuing stirring until cooling to the room temperature, carrying out inclusion for 8-20 hours at the temperature of minus 4-minus 10 DEG C, and filtering and separating the obtained urea inclusion mixture to obtain filtrate; (4) adding petroleum ether and dilute alkali liquor, extracting to obtain an organic phase, washing the organic phase to be neutral, drying with sodium sulphate anhydrous, and carrying out rotary evaporation to