Patent GB-772820-A (GB)
Title: Improvements in sequestering polyvalent metal ions
IPC: B01D21/01
Filed: 1955-02-11
Abstract: A process of sequestering polyvalent heavy metal ions having an atomic number greater than 24 comprises bringing together in solution salts of said heavy metals and a compound containing no more than two carboxyl bearing carbon atoms of the formula <FORM:0772820/IV(b)/1> wherein the empirical radical C6H13O5 represents the hexane pentol residue of a hexityl amine; R is hydrogen, (C1-C3) alkyl or (C2-C3) hydroxyalkyl; Y is hydrogen or an alkali metal; n is 1 or 2; a is 0 or 1; b is 0, 1 or 2; c is 0 or 1; d is 0 or 1 and a+b+c+d=2.  Ions capable of being sequestered are Ce++++, Cd++, Cu++, Fe++, Fe+++, Sn++, Hg++, Bi+++, Co++, Zn++, As+++, Sb+++, Ti++++, Zr++++, Mn++, Ni++ and Pb++.  Specified sequestering agents are N-methyl N-carboxymethyl, N - methyl N - carboxyethyl, N - ethyl N - carboxymethyl, N - ethyl N - carboxyethyl, N - 2 - hydroxyethyl N - carboxymethyl, N-carboxymethyl and N - propyl N - carboxymethyl glucamines; N-methyl N-carboxymethyl, N : N-bis - carboxymethyl and N - carboxymethyl fructamines; glucamine diacetic acid; glucamine dipropionic acid; N-methyl N-glucyl, N-ethyl N-glucyl, N-glucyl and N-fructyl aspartic acids; N-methyl N-glucyl, N-ethyl N-glucyl, N-glucyl, N-fructyl and N-methyl N-fructyl aminomalonic acids.  N : N-Bis-(carboxyalkyl) hexityl amines are prepared by reacting 2 moles. of an o -halogen fatty acid with one mole. of a hexityl amine. N-hexityl and N-alkyl N-hexityl aspartic acids are prepared by reacting equimolar amounts of an alkali maleate and a hexityl or N-alkyl hexityl amine.  N-Alkyl N-hexityl aminomalonic acids are prepared by reacting equimolar amounts of a halomalonic acid and an N-alkyl hexityl amine.  Specification 771,698 is referred to.ALSO:Iron may be prevented from precipitating during the kier boiling of cotton with sodium hydroxide and subsequent peroxide bleaching by the addition of a sequestering agent containing no more than two carboxyl bearing carbon atoms of the formula <FORM:0772820/IV(b)/1> wherein the empirical radical C6H13O5 represents the hexane pentol residue of a hexityl amine; R is hydrogen, (C1-C3) alkyl or (C2-C3) hydroxyalkyl; Y is hydrogen or an alkali metal; n is 1 or 2; a is 0 or 1; b is 0, 1 or 2; c is 0 or 1; d is 0 or 1 and the sum of a, b c and d is 2. Specified sequestering agents are N - methyl - N - carboxymethyl, N - methyl - N - carboxyethyl, N - ethyl - N - carboxymethyl, N ethyl - N - carboxyethyl, N - 2 - hydroxyethyl - N - carboxymethyl, N - carboxymethyl and N - propyl - N - carboxymethyl glucamines; N - methyl - N - carboxymethyl, N : N - bis-carboxymethyl and N-carboxymethyl fructamines; glucamine diacetic acid; glucamine dipropionic acid; N - methyl - N - glucyl, N - ethyl - N - glucyl, N - glucyl and N - fructyl aspartic acids; N - methyl - N - glucyl, N - ethyl-N - glucyl, N - glucyl, N - fructyl and N-methyl - N - fructyl aminomalonic acids.  Other sequestering agents such as ethylenediamine tetraacetic acid may be used in conjunction with the above sequestrants.ALSO:Compounds containing no more than two carboxyl bearing carbon atoms of the formula <PICT:0772820/III/1> wherein the empirical radical C6H13O5 represents the hexane pentol residue of a hexityl amine; R is hydrogen, (C1-C3) alkyl or (C2-C3) hydroxyalkyl; Y is hydrogen or an alkali metal; n is 1 or 2; a is 0 or 1; b is 0, 1 or 2; c is 0 or 1; d is 0 or 1; and the sum of a, b, c and d is 2, alone or in conjunction with other sequestering agents such as ethylenediamine tetraacetic acid, are used to sequester polyvalent heavy metal ions having an atomic number greater than 24. For this purpose the above compounds are added to fats, oils and soap formulations for prevention of rancidity and discoloration, to detergents and dishwashing compounds, and to sodium silicate solutions for use in the preparation of silica gels.  Alternatively, a solution of a polyvalent heavy metal (e.g. iron) complexed with one of the above sequestrants (e.g. N-methyl N-carboxymethyl glucamine) may be added to a solution of sodium silicate without precipitation and the solution treated with acid to form a gel in which the polyvalent heavy metal is evenly dispersed throughout.  Such silica gels may be employed as catalysts in the cracking of petroleums.ALSO:Solutions containing polyvalent heavy metal ions having an atomic number greater than 24 are treated with a sequestering agent containing no more than two carboxyl bearing carbon atoms of the formula: <FORM:0772820/I/1> wherein the empirical radical C6H13O4 represents the hexane pentol residue of a hexityl amine, R is hydrogen, (C1-C3) alkyl or (C2-C3) hydroxy - alkyl; Y is hydrogen or an alkali metal; n is 1 or 2; a is 0 or 1; b is 0, 1 or 2; c is 0 or 1; d is 0 or 1 and a + b + c + d = 2.  The process may be applied to the selective removal of ions such as Ce++++, Cd++, Cu++, Fe+++, Fe++, Sn++, Hg++, Bi+++, Co++, Zn++, As+++, Sb+++, Ti++++, Zr++++, Ni++, Mn++ and Pb++ from solutions also containing alkaline earth metal ions such as Ca++ and Mg++.  Other sequestering agents such as ethylenediamine tetraacetic acid may be used in conjunction with the above sequestrant.  Silica gel compositions containing complexes between one or more of the above polyvalent heavy metal ions and the above sequestering agents are used to supply trace elements to soils deficient in such elements.ALSO:Latex formulations are stabilized against traces of polyvalent heavy metal ions having an atomic number greater than 24 by the addition of a compound containing no more than two carboxyl bearing carbon atoms of the formula:  <FORM:0772820/V/1> wherein the empirical radical C6H13O5 represents the hexane pentol residue of a hexityl amine; R is hydrogen, (C1-C3) alkyl or (C2-C3) hydroxy-alkyl; Y is hydrogen or an alkali metal; n is 1 or 2; a is 0 or 1; b us 0, 1 or 2; c is 0 or 1; d is 0 or 1 and a+b+c+d=2.  Other sequestering agents such as ethylene diamine tetraacetic acid may be used in conjunction with the above sequestrant.