This paper presents a study related to obtaining glycerol as a by-product of the transesterification of edible oils used to be used in the preparation of hydrogel. The main results show that it is possible to obtain a pure and refined glycerol, in addition, it was observed that the parameters were within the regulations presented by several authors. It was also observed that the glycerol with better properties was obtained at 60 minutes at a temperature of 60ºC. In this way, it is possible to affirm that it is viable to use discarded oils as an alternative for their application in the elaboration of products that benefit the chemical, cosmetic, and pharmaceutical industries, as is the case of hydrogel, thus avoiding their incorporation into the environment.