Patent GB-930834-A (GB)
Title: Process for inhibiting corrosion
IPC: C23F11/14
Filed: 1959-12-01
Abstract: The corrosion of metals caused by contact with aqueous liquids is inhibited by providing in said liquid whilst in contact with the metal an organosilicon compound containing an amino group linked to a silicon atom by a divalent hydrocarbon group containing at least three carbon atoms, the amino group being attached to at least the third carbon atom removed from the silicon atom.  Silanes having the formula Z2NRSi­ may be used, wherein Z is a hydrogen atom, a monovalent hydrocarbon group, a monovalent hydrocarbon group substituted with an amino, amido, hydroxyl, ester, cyano or hydrocarbonoxy group, or is a divalent group derived from an oxirane compound by the opening of the oxirane ring and that links the nitrogen atom to the silicon atom; R is a divalent hydrocarbon group containing at least three carbon atoms, and the Z2N- group is attached to R by at least the third carbon atom removed from the silicon atom; and the free valencies of the silicon atom are linked to at least one alkoxy, aroxy or siloxy group and to 0-2 divalent groups represented by Z, monovalent hydrocarbon groups or NH2CnH2ngroups where n is at least three. Siloxanes which may be used contain one or more groups represented by <FORM:0930834/IV(a)/1> where Z and R are as above, R5 is a monovalent hydrocarbon group or a NH2CnH2n group (n being at least three), and b is 0-2.  The siloxanes may be homopolymeric containing only one type of group represented by the last-named formula, or may be copolymeric containing either two or more types of groups represented by the last-named formula or one or more of the latter groups together with one or more groups represented by <FORM:0930834/IV(a)/2> where R6 is a monovalent hydrocarbon group and e is 1-3. The organosilicon compound is preferably used in amounts of 0.0001-10 parts by weight per 100 parts by weight of the aqueous liquid.  Aqueous liquids to which the compounds may be added are pure water, inorganic solutions (e.g. sodium and calcium chloride refrigerating solutions, sulphuric acid pickling solutions, and corrosive well water or river water), and organic solutions (e.g. containing monohydric and polyhydric alcohols, hydroxyl and alkoxy end-blocked polyalkylene oxides, sulphoxides, formamides, and cyclic ethers free of olefinic unsaturation).  Metals which are protected include magnesium, aluminium, copper, chromium, iron, manganese, nickel, lead, silver, tin, beryllium, zinc and alloys thereof such as brass, bronze, solder and steel.  Many examples are given of suitable organosilicon compounds together with methods of preparing them.  Specifications 795,894, 847,803, 847,805, 855,703, 882,051, 882,052, 882,053, 882,054, 882,055, 882,056, 882,057, 882,060, 882,061, 882,062, 882,063, 882,069 and 882,096 are referred to.  Reference has been directed by the Comptroller to Specification 769,498.ALSO:The corrosion of metals caused by contact with aqueous liquids is inhibited by providing in said liquid whilst in contact with the metal an organosilicon compound containing an amino group linked to a silicon atom by a divalent hydrocarbon group containing at least three carbon atoms, the amino group being attached to at least the third carbon atom removed from the silicon atom.  Silanes having the formula Z2NRSi­ may be used, wherein Z is a hydrogen atom, a monovalent hydrocarbon group, a monovalent hydrocarbon group substituted with an amino, amido, hydroxyl, ester, cyano or hydrocarbonoxy group, or is a divalent group derived from an oxirane compound by the opening of the oxirane ring and that links the nitrogen atom to the silicon atom; R is a divalent hydrocarbon group containing at least three carbon atoms, and the Z2N-group is attached to R by at least the third carbon atom removed from the silicon atom; and the free valencies of the silicon atom are linked to at least one alkoxy, aroxy or siloxy group and to 0-2 divalent groups represented by Z, monovalent hydrocarbon groups or NH2CnH2ngroups, where n is at least three.  Siloxanes which may be used contain one or more groups represented by <FORM:0930834/II/1> where Z and R are as above, R5 is a monovalent hydrocarbon group or a NH2CnH2n group (n being at least three), and b is 0-2.  The siloxanes may be homopolymeric containing only one type of group represented by the last-named formula, or may be copolymeric containing either two or more types of groups represented by the last-named formula or one or more of the latter groups together with one or more groups represented by <FORM:0930834/II/2> where R6 is a monovalent hydrocarbon group and e is 1-3. The organosilicon compound is preferably used in amounts of 0.0001-10 parts by weight per 100 parts by weight of the aqueous liquid.  Aqueous liquids to which the compounds may be added are pure water, inorganic solutions (e.g. sodium and calcium chloride refrigerating solutions, sulphuric acid pickling solutions, and corrosive well water or river water), and organic solutions (e.g. containing monohydric and polyhydric alcohols, hydroxyl and alkoxy end-blocked polyalkylene oxides, sulphoxides, formamides, and cyclic ethers free of olefinic unsaturation).  Metals which are protected include magnesium, aluminium, copper, chromium, iron, manganese, nickel, lead, silver, tin, beryllium, zinc and alloys thereof such as brass, bronze, solder and steel.  Many examples are given of suitable organosilicon compounds together with methods of preparing them. Specifications 795,894, 847,803, 847,805, 855,703, 882,051, 882,052, 882,053, 882,054, 882,055, 882,056, 882,057, 882,060, 882,061, 882,062, 882,063, 882,069 and 882,096 are referred to.  Reference has been directed by the Comptroller to Specification 769,498.