Process for the preparation of an inhibitor of mineral salt deposits

The invention relates to a process for the preparation of an inhibitor of mineral salt deposits. The process comprises reacting formaldehyde, phosphorus trichloride and a nitrogen-containing condensation product in an aqueous medium at a temperature of 35 to 50 DEG C. The nitrogen-containing condensation product used is a product which is obtained by reaction of epichlorohydrin with ammonia, taken in the form of an aqueous solution, at temperatures of 5 to 20 DEG C and a molar ratio of the reagents of 1 : 5-1 : 15 with subsequent treatment of the reaction mixture with an alkali metal hydroxide, taken in an amount of 1.0-1.1 mol per 1 mol of the epichlorohydrin, and distilling off the unreacted ammonia. The said product has the following composition in % by weight: mixture of 1,3-diamino-2-propanol and 1,3-diamino-2-propanol derivative of the general formula in which n = 2-5...3-33 alkali metal chloride...2-25 water...to make up to 100. Per 100 parts by mass of the mixture of 1,3-diamino-2-propanol and 1,3-diamino-2-propanol derivative having the said general formula, 255-300 parts by mass of formaldehyde and 400-500 parts by mass of phosphorus trichloride are taken. The invention can be used in water treatment plants in distillative evaporators for the desalination of mineralised waters and in the extraction, transporting and treatment of mineral oil and natural gas.