Dehydration of castor oil is carried out at about 250 degree Celsius in the presence of catalysts (e.g., concentrated sulphuric acid, activated earth) and under an inert atmosphere or vacuum. Under this condition of dehydration, the hydroxyl group and adj
Castor Oil has only one double bond in each Fatty Acid chain and so is classified as Non-drying Oil. However, it can be dehydrated to give Semi-drying or Drying Oil.
It is used as a Drying Oil extensively in paints and varnishes