Aqueous solution containing aluminum ions, lactate ions, and phosphate ions, and a method for their production

Abstract

The invention relates to an aqueous solution containing aluminum ions, characterized in that the solution contains aluminum ions in a proportion of 0.5-15% (converted, if necessary, to Al.sup.3+) based on the total mass of the solution, as well as anions of lactic acid (lactate ions) and of phosphoric acid (phosphate ions), and has the theoretical composition Al.sup.3+.sub.A(C.sub.3H.sub.5O.sub.3.sup.).sub.x.AS.sup.M.sub.y.A(H.sub.2PO.sub.4.sup.).sub.z.A(OH).sup..sub.(3A-x.A-M.y.A-z.A), wherein S is the anion of an acid with the charge M, x is a value in the range of 0.5-2.8, y is a value in the range of 0-1.5, and z is a value in the range of 0.01-1.5.

Claims

1. An aqueous solution comprising aluminum ions, wherein the solution comprises aluminum ions in a proportion of 1.5% -15% by weight (converted to Al.sup.3+) based on the total mass of the solution, as well as anions of lactic acid (lactate ions) and of phosphoric acid (phosphate ions), wherein the molar proportion of the lactate ions is in the range of 0.01-2.99 times the molar proportion of Al.sup.3+, and the molar proportion of phosphate ions is in the range of 0.01-2.99 times the molar proportion of Al.sup.3+.

2. The aqueous solution according to claim 1, wherein the solution further comprises an anion of at least a third acid.

3. The aqueous solution according to claim 2, wherein the third acid is selected from a group consisting of an amino acid, carboxylic acid, citric acid, tartaric acid, malic acid, oxalic acid, glycolic acid, succinic acid, gluconic acid, glycine, acetic acid, sulfuric acid, and combinations thereof.

4. The aqueous solution according to claim 1, wherein the solution comprises at least one additional cation, wherein the cation is selected from a group consisting of alkali metal ions, alkali earth ions, ammonium ions, cations of one or a plurality of transition or rare earth metals, and combinations thereof.

5. The aqueous solution according to claim 4, wherein the cation is selected from a group consisting of Na.sup.+, K.sup.+, Ca.sup.2+, Mg.sup.2+, Zr.sup.2+, NH.sub.4.sup.+, and combinations thereof.

6. The aqueous solution according to claim 1, wherein the solution comprises clusters which include the compound
Al.sup.3+.sub.A(C.sub.3H.sub.5O.sub.3.sup.).sub.xAS.sup.M.sub.yA(H.sub.2PO.sub.4.sup.).sub.zA(OH).sup..sub.(3A-xA-MyA-zA), wherein S is an anion of an optionally present third acid with the charge M, x is a value in the range of 0.01-2.99, y is a value in the range of 0-2.8, and z is a value in the range of 0.05-2.9.

7. The aqueous solution according to claim 6, wherein (3A-xA-MyA-zA) is >0.

8. The aqueous solution according to claim 6, wherein x is a value in the range of 1.0-1.5.

9. The aqueous solution according to claim 6, wherein y is a value in the range of 0-1.0.

10. The aqueous solution according to claim 6, wherein z is a value in the range of 0.3-1.25.

11. The aqueous solution according to claim 1, wherein the solution is stable in a temperature range of 0 C.-80 C.

12. The aqueous solution according to claim 11, wherein the solution is stable in storage at a temperature of <30 C. for a period >one month.

13. The aqueous solution according to claim 11, wherein the solution is stable in storage at a temperature of <10 C. for a period >12 months.

14. A method for creating an aqueous solution, wherein the solution comprises aluminum ions in a proportion of 1.5%-15% by weight (converted to Al.sup.3+) based on the total mass of the solution, as well as anions of lactic acid (lactate ions) and of phosphoric acid (phosphate ions), wherein the molar proportion of the lactate ions is in the range of 0.01-2.99 times the molar proportion of Al.sup.3+and the molar proportion of phosphate ions is in the range of 0.01-2.99 times the molar proportion of Al.sup.3+, said method comprising the following steps: a) providing water in a reaction vessel; b) adding a basic aluminum salt into the reaction vessel while stirring; c) adding a lactic acid and/or a lactate and, in parallel or offset in time, adding a phosphoric acid and/or a phosphate; d) stirring the resulting mixture, wherein the sequence for performing the steps b) and c) is discretionary.

15. The method according to claim 14, wherein clusters of the compound Al.sup.3+.sub.A(C.sub.3H.sub.5O.sub.3.sup.).sub.xAS.sup.M.sub.yA(H.sub.2PO.sub.4.sup.).sub.zA(OH).sup.(3A-xA-MyA-zA) are created, wherein S is an anion of an optionally present third acid with the charge M, x is a value in the range of 0.01-2.99, y is a value in the range of 0-2.8, and z is a value in the range of 0.05-2.9.

16. The method according to claim 14, wherein step c) is performed at a temperature >25 C.

17. The method of claim 16 wherein step c) is performed at a temperature at 60-70 C.

18. The method of claim 16 wherein step c) is performed under reflux.

19. The method according to claim 14, further comprising a filtration step after step c).

20. The method of claim 14, wherein the basic aluminum salt is selected from a group consisting of Al carbonate, Al hydroxide, Al oxide, an aluminate, and combinations thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) Examples for the aforementioned solution and a method for their production are exemplarily given in the following:

Example 1

(2) Theoretical Composition of the Dissolved Substances: Al.sup.3+(C.sub.3H.sub.5O.sub.3).sup..sub.1.5(H.sub.2PO.sub.4).sup.(OH).sup..sub.0.5

(3) For producing such a solution, aluminum is prepared in the form of a basic salt (carbonate, hydroxide, oxide, aluminate, preferably hydroxide) in an aqueous suspension with 10%-20% solids by weight (wt.-%). A suitable ingredient are, for example, the amorphous substances known as aluminum oxide hydrates, created in a known manner through precipitation from an aluminum salt solution through the addition of bases. Although the use of crystalline aluminum hydroxides such as bayerite (alpha-Al(OH).sub.3), hydrargillite (gammaAl(OH).sub.3), boehmite (alpha-AlO(OH)) or diaspore (gamma-AlO(OH)) is not excluded, it is less preferred because these aluminum salts typically dissolve more slowly in acids than amorphous aluminum hydroxide or oxide hydrate. The most reactive is naturally freshly precipitated aluminum hydroxide or oxide hydrate, but commercially available aluminum hydroxides or oxide hydrates are very suitable as well. An example of a suitable raw material is aluminum oxide, hydrated (powder, according to the European Pharmacopoeia, 9.sup.th ed., 47.0%-60.0% Al.sub.2O.sub.3, Dr. Paul Lohmann GmbH KG, article number 511066100). Then, lactate and phosphoric acid are admixed to it while stirring and brought to reaction at a temperature of slightly over 40 C. This produces a clear to slightly opaque solution that is freed of possibly present (undissolved or precipitated) solid components via filtration. The filtration takes place here at a maximum of 80 C. Further tests have shown that filtration at low temperatures can be advantageous. The solution obtained in this manner is stable in storage at room temperature. The solution is storage stable even above room temperature. A reversible viscous gel forms only above 60 C. Such a solution is suitable, for example, for use in plastics, adhesives, lacquers, wastewater treatment, or flocculating agents.

Example 2

(4) Theoretical Composition of the Dissolved Substances: Al.sup.3+(C.sub.3H.sub.5O.sub.3).sup..sub.1.2(H.sub.2PO.sub.4).sup..sub.0.8(OH).sup.

(5) For producing a solution having the aforementioned composition of the solute, 1220 kg of ultra-pure water, 196 kg lactic acid, 147 kg phosphoric acid, and 1.59 kmol Al.sup.3+ in the form of a basic salt were used. The water was first provided in a solution tank. Lactic acid and phosphoric acid are slowly admixed to the receiver while stirring. Unlike in the aforementioned Example 1, the aluminum compound is only admixed into the provided solution afterwards. It is then heated to 60-65 C. In order to ensure the long-term stability of the solution, the mixture obtained is kept at 60-65 C. for 202 hours under reflux cooling. After completion of the resulting reaction, the mixture/solution is filtered clear via a filter press and bottled.

(6) The following list shows examples of compounds for which stable solutions can be achieved.

(7) Compounds that are included here not only contain additional acid residues, but also some that comprise additional anions of this type. This list is only exemplary, and there are additional examples of stable aqueous solutions according to the invention.

(8) Compounds without Additional Anions (S):

(9) Al.sub.4(C.sub.3H.sub.5O.sub.3).sub.6(H.sub.2PO.sub.4).sub.3OH).sub.3

(10) Al.sub.5(C.sub.3H.sub.5O.sub.3).sub.6(H.sub.2PO.sub.4).sub.3(OH).sub.6

(11) Al.sub.6(C.sub.3H.sub.5O.sub.3).sub.6(H.sub.2PO.sub.4).sub.4(OH).sub.8

(12) Compounds with Additional Anions (S):

(13) S=sulfate:

(14) Al.sub.4(C.sub.3H.sub.5O.sub.3).sub.3(SO.sub.4).sub.3(H.sub.2PO.sub.4)(OH).sub.2

(15) Al.sub.6(C.sub.3H.sub.5O.sub.3).sub.3(SO.sub.4).sub.6H.sub.2PO.sub.4)(OH).sub.2

(16) S=oxalate

(17) Al.sub.5.4(C.sub.3H.sub.5O.sub.3).sub.5(C.sub.2O.sub.4).sub.0.52(H.sub.2PO.sub.4).sub.3(OH).sub.7.16

(18) Al.sub.5.4(C.sub.3H.sub.5O.sub.3).sub.5(C.sub.2O.sub.4).sub.0.52(H.sub.2PO.sub.4).sub.3(OH).sub.7.16

(19) S=citrate

(20) Al.sub.5.7(C.sub.3H.sub.5O.sub.3).sub.5(C.sub.6H.sub.5O.sub.7).sub.0.33(H.sub.2PO.sub.4).sub.3(OH).sub.8.11

(21) Al.sub.5.7(C.sub.3H.sub.5O.sub.3).sub.5(C.sub.6H.sub.5O.sub.7).sub.0.66(H.sub.2PO.sub.4).sub.3(OH).sub.7.12

(22) S=succinate

(23) Al.sub.4.4(C.sub.3H.sub.5O.sub.3).sub.5(C.sub.4H.sub.4O.sub.4).sub.0.52(H.sub.2PO.sub.4).sub.3(OH).sub.4.16

(24) Al.sub.4.4(C.sub.3H.sub.5O.sub.3).sub.5(C.sub.4H.sub.4O.sub.4)(H.sub.2PO.sub.4).sub.3(OH).sub.3.2

(25) S=malate

(26) Al.sub.5.7(C.sub.3H.sub.5O.sub.3).sub.5(C.sub.4H.sub.4O.sub.5).sub.0.52(H.sub.2PO.sub.4).sub.3(OH).sub.8.06

(27) AL.sub.6(C.sub.3H.sub.5O.sub.3).sub.3(C.sub.4H.sub.4O.sub.5).sub.3(H.sub.2PO.sub.4).sub.3(OH).sub.6

(28) S=acetate

(29) Al.sub.7(C.sub.3H.sub.5O.sub.3).sub.5(C.sub.2H.sub.3O.sub.2)(H.sub.2PO.sub.4).sub.3(OH).sub.12

(30) Al.sub.5.7(C.sub.3H.sub.5O.sub.3).sub.5(C.sub.2H.sub.3O.sub.2)(H.sub.2PO.sub.4).sub.3(OH).sub.8.1

(31) S=glycinate

(32) Al.sub.6(C.sub.3H.sub.5O.sub.3).sub.6(C.sub.2H.sub.4NO.sub.2)(H.sub.2PO.sub.4).sub.3(OH).sub.8

(33) Al.sub.7(C.sub.3H.sub.5O.sub.3).sub.6(C.sub.2H.sub.4NO.sub.2).sub.2(H.sub.2OH.sub.4).sub.3(OH).sub.10

(34) The concentration of the aluminum ions here is in the range of 0.5%-15% by weight (converted, if necessary to Al.sup.3+) based on the total mass of the solution.

(35) The pH value of the particular solution is preferably in the acid range, more preferably between 1 and 6. In a further preferred embodiment, the solution has a pH value between 2 and 4.

(36) In another embodiment of the invention, the total concentration of the dissolved solids (in water) is in a range of >10% by weight based on the total mass of the solution. Particularly preferred are solutions that have a total concentration of the dissolved solids (in water) in a range >15% by weight based on the total mass of the solution.

(37) It has been shown, however, that high concentrations can lead to a reduced long-term stability of the solution. It is therefore preferred that the total concentration of the dissolved solids (in water) be in a range of <50% by weight based on the total mass of the solution.

(38) Particularly preferred are solutions that have a total concentration of the dissolved solids (in water) in a range of <35% by weight based on the total mass of the solution. Particularly preferred are solutions that have a total concentration of the dissolved solids (in water) in a range of 15%-30% by weight based on the total mass of the solution.

(39) In an embodiment, the molar proportion of phosphate is higher than that of the lactate. The following compounds were identified as examples of stable solutions of this type.

(40) Al.sub.6.7(C.sub.3H.sub.5O.sub.3).sub.2(C.sub.4H.sub.4O.sub.5).sub.4(H.sub.2PO.sub.4).sub.3(OH).sub.7.1

(41) Al.sub.5.8(C.sub.3H.sub.5O.sub.3)(C.sub.4H.sub.4O.sub.5).sub.5(H.sub.2PO.sub.4).sub.3(OH).sub.3.4

(42) In this case, malate is used as the additional anion. There are also additional preferred examples of stable solutions in which the stochiometric ratio between lactate and phosphate is equal, but, because of the higher molar masses of the phosphate, the mass ratio between lactate and phosphate is shifted in favor of the phosphate. Examples of stable solutions in which the molar ratio between lactate and phosphate is equal are illustrated in the following examples. Malate is also used here as the third anion, which is not necessary, however, and other substances may be used as the third acid as well.

(43) Al.sub.6(C.sub.3H.sub.5O.sub.3).sub.3(C.sub.4H.sub.4O.sub.5).sub.3(H.sub.2PO.sub.4).sub.3(OH).sub.6

(44) Al.sub.6(C.sub.3H.sub.5O.sub.3).sub.3(C.sub.4H.sub.4O.sub.5).sub.3(H.sub.2PO.sub.4).sub.3(OH).sub.6

(45) The availability of a large selection of additional acids for the choice of the third acid is demonstrated via the examples illustrated below in which amino acids were used as the third acid. In addition to the illustrated amino acids glutamic acid and aspartic acid, other (preferably simple) carboxylic or inorganic acids, such as the amino acids glycine, tyrosine, glutamate, pyroglutamate, aspartate, etc., are also possible as third acids.

(46) Al.sub.4(C.sub.3H.sub.5O.sub.3).sub.6(C.sub.5H.sub.8NO.sub.4).sub.1.5(H.sub.2PO.sub.4).sub.3(OH).sub.1.5

(47) Al.sub.4(C.sub.3H.sub.5O.sub.3).sub.4(C.sub.5H.sub.8NO.sub.4)(H.sub.2PO.sub.4).sub.4(OH).sub.3

(48) With aspartic acid:

(49) Al.sub.4(C.sub.3H.sub.5O.sub.3).sub.6(C.sub.4H.sub.6NO.sub.4).sub.1.5(H.sub.2PO.sub.4).sub.3(OH).sub.1.5

(50) Al.sub.4(C.sub.3H.sub.5O.sub.3).sub.6(C.sub.4H.sub.6NO.sub.4(H.sub.2PO.sub.4)(H.sub.2PO.sub.4).sub.3(OH).sub.2

(51) Examples of the aforementioned stable solutions in which an inorganic acid is used as the third acid (or as the resulting anion) are shown above by way of example (S=sulfate).

(52) It is also feasible that the (molar) amount of the third ion (or of the third acid) used is equal to or even larger than that of lactate and phosphate. The following table shows compounds as examples of stable solutions. The last example, in particular, shows that a stable solution may even be obtained if the (molar) amount of sulfate exceeds the (molar) total amount of lactate and phosphate:

(53) TABLE-US-00001 Al.sub.4(C.sub.3H.sub.5O.sub.3).sub.3(SO.sub.4).sub.3(H.sub.2PO.sub.4)(OH).sub.2 Al.sub.5(C.sub.3H.sub.5O.sub.3).sub.3(SO.sub.4).sub.3(H.sub.2PO.sub.4).sub.2(OH).sub.4 Al.sub.5(C.sub.3H.sub.5O.sub.3).sub.6(SO.sub.4).sub.3(H.sub.2PO.sub.4)(OH).sub.2 Al.sub.6(C.sub.3H.sub.5O.sub.3).sub.3(SO.sub.4).sub.6(H.sub.2PO.sub.4)(OH).sub.2

(54) All examples listed in the table resulted in clear solutions.

(55) The applicant reserves the right to claim all features disclosed in the application documents as essential to the invention, insofar as they are novel with respect to the prior art, either individually or in combination. Moreover, it is to be noted that features were also described in the individual examples that may be advantageous in their own right. The person skilled in the art immediately recognizes that a specific feature described in an example can also be advantageous even without the adoption of additional features from this example. The person skilled in the art further recognizes that advantages may also result from a combination of a plurality of features demonstrated individually or in different examples.

(56) Having now fully described the present invention in some detail by way of illustration and examples for purposes of clarity of understanding, it will be obvious to one of ordinary skill in the art that the same can be performed by modifying or changing the invention within a wide and equivalent range of conditions, formulations and other parameters without affecting the scope of the invention or any specific embodiment thereof, and that such modifications or changes are intended to be encompassed within the scope of the appended claims.

(57) When a group of materials, compositions, components or compounds is disclosed herein, it is understood that all individual members of those groups and all subgroups thereof are disclosed separately. Every formulation or combination of components described or exemplified herein can be used to practice the invention, unless otherwise stated. Whenever a range is given in the specification, for example, a temperature range, a time range, or a composition range, all intermediate ranges and subranges, as well as all individual values included in the ranges given are intended to be included in the disclosure. Additionally, the end points in a given range are to be included within the range. In the disclosure and the claims, and/or means additionally or alternatively. Moreover, any use of a term in the singular also encompasses plural forms.

(58) As used herein, comprising is synonymous with including, containing, or characterized by, and is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. As used herein, consisting of excludes any element, step, or ingredient not specified in the claim element. As used herein, consisting essentially of does not exclude materials or steps that do not materially affect the basic and novel characteristics of the claim. Any recitation herein of the term comprising, particularly in a description of components of a composition or in a description of elements of a device, is understood to encompass those compositions and methods consisting essentially of and consisting of the recited components or elements.

(59) One of ordinary skill in the art will appreciate that starting materials, device elements, analytical methods, mixtures and combinations of components other than those specifically exemplified can be employed in the practice of the invention without resort to undue experimentation. All art-known functional equivalents, of any such materials and methods are intended to be included in this invention. The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention that in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. The invention illustratively described herein suitably may be practiced in the absence of any element or elements, limitation or limitations which is not specifically disclosed herein. Headings are used herein for convenience only.

(60) All publications referred to herein are incorporated herein to the extent not inconsistent herewith. Some references provided herein are incorporated by reference to provide details of additional uses of the invention. All patents and publications mentioned in the specification are indicative of the levels of skill of those skilled in the art to which the invention pertains.

(61) References cited herein are incorporated by reference herein in their entirety to indicate the state of the art as of their filing date and it is intended that this information can be employed herein, if needed, to exclude specific embodiments that are in the prior art.