Products for inhibiting corrosion and for protection against corrosion

Anti-corrosion agents are prepared by reacting an alkali metal nitrile with a natural resin containing free abietic acid, e.g. tall oil. An aqueous solution of the nitrile is preferably employed at a temperature below 60 DEG C. The abietic acid or material containing it may be an alcoholic solution to give a solution of the product in alcohol. Reaction may be performed in a composition whose anti-corrosive properties are to be inhibited or in a composition to be used for protecting against corrosion. Thus when neutralizing compositions containing abietic acid the aqueous alkali used, e.g. caustic potash may contain the alkaline nitrile in solution, to produce an agent for emulsifying mineral oil to give an emulsion which is non-corrosive or may even be used for preventing corrosion. Water-soluble products yielding anti-corrosive coatings removable with water or aqueous alkali may be obtained by mixing with soaps, aminoalcohol soaps or alkaline sulphonates. Products insoluble in water giving coatings removable by organic solvents are obtained by mixing with amines, polyamines, soaps thereof, or fatty amides, amidoalcohols, or alkaline earth sulphonates. The products may be combined with drying oils and pigments to give anti-corrosive paint. In solution they may be used for impregnating wrapping materials such as paper or cardboard, or may be added to the pulp from which such products are made. In examples (1) A mixture containing abietic resin or colophony, mahogany sodium petroleum sulphonate, tall oil or oleine, ethyl alcohol or a glycol, is neutralized with caustic potash containing sodium nitrite. The product may be used to emulsify mineral oil to give a sprayable product for protecting metal against corrosion. (2) An aqueous alcoholic solution of sodium nitrite is reacted with alcoholic colophony to yield an anti-corrosive product. (3) The product of Example 2 is mixed with calcium oil soluble petroleum sulphonate. (4) The product of Example 2 is mixed with a monoethanolamide of tall oil or of naphthenic acid. (5) The product of Example 2 is mixed with a fatty amine or an alkylaminopropylene diamine having an alkyl group with 8-18 carbon atoms, or a tall oil or naphthenic acid soap of such an amine. The mixture may be diluted with dichlorethane, trichlorethylene or perchlorethylene to give a water insoluble anti-corrosive coating. (6) Aqueous alcoholic sodium nitrite is reacted with alcoholic colophony mixed with tall oil or naphthenic acid. (7) The products of examples 2-6 are mixed with pigments, fillers and pulverulent nitriles of polyvalent metals to give anti-corrosive paints. (8) The alcohol used in Example (2) was mixed with other organic solvent (listed) to give a product less soluble in water and more soluble in oils.ALSO:Anti-corrosion agents are prepared by reacting an alkali metal nitrite with a natural resin containing free abietic acid, e.g. tall oil. An aqueous solution of the nitrite is preferably employed at a temperature below 60 DEG C. The abietic acid or material containing it may be in alcoholic solution to give a solution of the product in alcohol. Reaction may be performed in a composition whose anti-corrosion properties are to be inhibited or in a composition to be used for protecting against corrosion. Thus when neutralizing compositions containing abietic acid, the aqueous alkali used, e.g. caustic potash, may contain the alkaline nitrite in solution to produce an agent for emulsifying mineral oil to give an emulsion which is non-corrosive or may even be used for preventing corrosion. In examples: (1) a mixture containing abietic resin or colophony, mahogany sodium petroleum sulphonate, tall oil or oleine, ethyl alcohol or a glycol, is neutralized with caustic potash containing sodium nitrite. The product may be used to emulsify mineral oil to give a sprayable product for protecting metal against corrosion.ALSO:Anti-corrosive emulsifying agents are prepared by reacting an alkali metal nitrite with a natural resin containing free abietic acid, e.g. tall oil. Reaction may be performed in a composition whose anti-corrosion properties are to be inhibited, or in a composition to be used for protecting against corrosion. Thus when neutralizing compositions containing abietic acid, the aqueous alkali used, e.g. caustic potash, may contain the alkaline nitrite in solution, to produce an agent for emulsifying mineral oil, to give an emulsion which is non-corrosive or may even be used for preventing corrosion. In examples: (1) a mixture containing abietic resin or colophony, mahogany sodium petroleum sulphonate, tall oil or oleine, ethyl alcohol or a glycol, is neutralized with caustic potash containing sodium nitrite. The product may be used to emulsify mineral oil.ALSO:Paper or cardboard is rendered impermeable and water-proof by impregnation with a solution of an agent formed by reaction of an alkali metal nitrite with an abietic resin. The agent may alternatively be added to the pulp from which paper is formed.