Water and solvent should be insoluble and the solvent should have as least as greatly solubility for the dissolved materials. Substituted amines will react with some other materials in water from the seawater and a chemical treatment may be required. Another extraction system of a cheaper solvent relative miscible with water is used at the temperature of its maximum solubility for water. After the extraction, the miscible solvent remains dissolved in the fresh water. The phase separation may be steam-distilled out of the saturated solution. This aqueous solution of water-miscible solvent may be contacted with a second solvent in order to extract from it the first solvent. The mixtures of the two solvents are then separated by distillation.