Ricinoleic acid is manufactured for industries by saponification or fractional distillation of hydrolyzed castor oil. Its bleaching, cleaning, deodorizing and caustic effects are due to oxidation and hydrolysis (saponification). Sodium hydroxide is traditionally used in soap making (cold process soap, saponification). Neutralization of fatty acids, i.e. saponification, is a widely practiced route to metallic soaps. Methyl esters also are susceptible to demethylation, which is usually achieved by saponification. The production of toilet soaps usually entails saponification of fats (triglycerides). "Double" saponification of DBP leads to phthalic acid and 1-butanol. After saponification was completed, the resulting glycerol was left in the batch. These applications use sodium palmitate, which is commonly obtained by saponification of palm oil. The reaction of fatty acids with base is the other main method of saponification. Most commonly, sodium laurate is obtained by saponification of various oils, such as coconut oil. Being lipophilic, it functions as a phase transfer catalyst for the saponification of fats. Extinguishers of this type are designed to extinguish cooking fats and oils through saponification. This reaction, saponification, is the basis of soap making. This reaction is known as saponification because it is used in the preparation of soap.