Patent GB-927617-A (GB)
Title: Method for treating aqueous solutions to sequester metal ions contained therein
IPC: D06L4/12
Filed: 1959-08-06
Abstract: Bottle washing compositions comprise a neutral acid or alkaline aqueous solution containing as a sequestrant for polyvalent metal ions an organic acylation product of phosphorous acid or of a partial ester of phosphorus acid and having a formula incorporating either the group:  <FORM:0927617/III/1> in which R2 is a hydrogen atom or a hydrocarbon residue, or a salt thereof.  Specified acylation products are CH3COP(O)(OH)(OC2H5), CH3COP(O)(OC4H9)(OH), C6H5COP(O) (OH)(OC2H5), C2H5COP(O)(OH)(OC2H5), [(HO)2P(O)]2C(CH3)(OH) and [C2H5OP(O) (OH)CO]2(CH2)4.  The free acids obtained by saponifying the specified esters may also be used.  Specification 810,642 is referred to.ALSO:An organic acylation product of phosphorous acid or of a partial ester of phosphorous acid and having a formula incorporating either the group <FORM:0927617/IV(a)/1> or <FORM:0927617/IV(a)/2> in which R2 is a hydrogen atom or a hydrocarbon residue, or a salt of said acylation product, is added to an aqueous solution containing polyvalent metal ions, particularly di- and tri-valent ions, so as to sequester said metal ions in the form of a complex with said acylation product or with said salt of the acylation product.  The organic acylation product or its salt may be used in acid, neutral or alkaline solution and specified acylation products are those having the formulae: CH3COP(O)(OC2H5)(OH), CH3COP(O)(OC4H9)(OH), C6H5CO.P(O)(OC2 H5)(OH), [C2H5OP(O)(OH)CO]2(CH2)4, C2H5 COP(O)(OC2H5)(OH) and [(HO)2P(O)]2C (CH3)OH.  The free acids which can be prepared by saponification of the esters may also be used as may a product obtained by reacting phosphorous acid with acetyl chloride in the presence of acetic anhydride.  Specified polyvalent metal ions are Mg, Ca, Zn, Cu, Fe and Ni.  The process may be applied to the softening of hard water (see Group I), to the descaling of textiles in which alkaline earth metal salts have been deposited, to the lessening of the ash content in fabrics which have been treated with soap- or pyrophosphate-containing washing agents, and in dyebaths for textiles (see Group IV(c)), in the washing of bottles so as to avoid precipitation of calcite or deposition of iron hydroxide (see Group III), to the prevention of decomposition of percompounds and products containing hypochlorite, to supplying plants with trace elements, and to compleximetric titrations for the determination of Mg, Ca, Zn, Cu and Fe ions.  Specification 810,642 is referred to.ALSO:An organic acylation product of phosphorous acid or of a partial ester of phosphorous acid and having a formula incorporating either the group <FORM:0927617/IV(a)/1> or <FORM:0927617/IV(a)/2> in which R2 is a hydrogen atom or a hydrocarbon residue or a salt of said acylation product is added to an aqueous solution containing polyvalent metal ions, particularly di- and tri-valent ions, so as to sequester said metal ions in the form of a complex with the organophosphorous compound.  The process may be applied to the descaling of textiles in which alkaline earth metal salts have been deposited, to the lessening of the ash content in fabrics which have been treated with soap or pyrophosphate-containing washing agents, to prevent the deposition of iron compounds, especially iron hydroxide on textiles, and to the formation of complexes with metal ions present in dyebaths for textiles so as to avoid the production of undesired shades of colour.  Specified polyvalent metals are Ca, Mg, Zn, Cu, Fe and Ni. The acylation products may be used in acid, neutral or alkaline solution.  Specified acylation products are: CH3COP(O)(OH)(OC2H5), CH3COP(O)(OH)(OC4H9), C6H5COP(O)(OH)(OC2H5), C2H5COP(O)(OH)(OC2H5), [C2H5OP(O)(OH)CO]2(CH2)4, and [(HO)2P(O)]2C(CH3)(OH).  The free acids obtained by saponification of the specified esters may also be used. Specification 810,642 is referred to.ALSO:An organic acylation product of phosphorous acid or of a partial ester of phosphorous acid and having a formula incorporating either the group: <FORM:0927617/I/1> in which R2 is a hydrogen atom or a hydrocarbon residue, or a salt of said acylation product, is added to water containing polyvalent metal ions, e.g. calcium, which form part of a water hardness producing agent so as to sequester the metal ions in the form of a complex with the organophosphorus compound.  The organophosphorus compound may be used in acid, neutral or alkaline solution.  Other polyvalent metal ions specified are magnesium, zinc, copper, nickel, and iron.  Specified acylation products are CH3COP(:O)(OH)(OC2H5), CH3COP):O)(OH)(OC4H9), C6H5COP(:O)(OH) (OC2H5), (CH2)4 [C2H5)OP(:O) (OH)CO]2, [(HO) P(:O)OH]2C(CH3)(OH) and C2H5COP(:O)(OH) (OC2H5).  The free acids corresponding to the specified esters may also be used.  Specification 810,642 is referred to.