AU596264B2

AU596264B2 - The use of phosphonoalkanecarboxylic acid partial esters for the extraction of metals

Info

Publication number: AU596264B2
Application number: AU10013/88A
Authority: AU
Inventors: Helmut Blum; Werner Dr. Schwab
Original assignee: Henkel AG and Co KGaA
Current assignee: Henkel AG and Co KGaA
Priority date: 1987-01-08
Filing date: 1988-01-07
Publication date: 1990-04-26
Anticipated expiration: 2008-01-07
Also published as: AU1001388A; JPS63183135A; DE3782639D1; DE3700326A1; ZA8897B; EP0274120A2; GR3006859T3; EP0274120B1; NO880053L; ES2052543T3; PT86497B; NO880053D0; TR23343A; BR8800038A; ATE82331T1; PL270008A1; PT86497A; EP0274120A3

Abstract

Products of the reaction of phosphonoalkanecarboxylic acids of the general formulae (I) <IMAGE> in which R<1> is COOH or PO3H2 and R<2> is CH2COOH or PO3H2 with the proviso that R<1> and R<2> are different, or (II) <IMAGE> in which m is 0 or 1 and n is 1 or 2, with alcohols of the general formula (III) R<3>-OH (III) in which R<3> is a straight-chain or branched alkyl radical having 4 to 14 carbon atoms, in a molar ratio of 1 : 1 to 1 : (p - 0.5), p being the valency of the phosphonoalkanecarboxylic acids of the general formulae (I) or (II), or mixtures of such reaction products are used for the extraction of metal ions from acidic aqueous solutions by means of organic solvents.

Description

5845/2 1 1~ ~r~

I

S F Ref: 38816 FORM COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 COMPLETE SPECIFICATIOIN59 *QiJ' 4W

(ORIGINAL)

FOR OFFICE USE: Class Int Class Complete Specification Lodged: Accepted: Published: Priority: Related Art: S

OS,

"Al aa 6k L.r3c3t fol, Name and Address of Applicant: 4 Henkel Kommanditgesellschaft auf Aktien Henkelstrasse 67 4000 Dusseldorf-Holthausen FEDERAL REPUBLIC OF GERMANY Spruson Ferguson, Patent Attorneys Level 33 St Martins Tower, 31 Market Street Sydney, New South Wales, 2000, Australia Address for Service: Complete Specification for the invention entitled: The Use of Phosphonoalkanecarboxylic for the Extraction of Metals The following statement is a full description best method of performing it known to me/us Acid Partial Esters of this invention, including the 5845/3 1- -1 D 7604 A B S T R A C T The use of phosphonoalkanecarboxylic acid partial esters for the extraction of metals The invention relates to the use of reaction products of phosphonoalkanecarboxylic acids corresponding to the following general formula ooo* R COOH 2 H-C CH-R (I) *SO sg SC*

HO-P=O

I

OH

50 1 2 in which R represents COOH or PO H 2 and R represents 3 1 2

CH

2 COOH or PO 3

H

2 with the proviso that R and R are 10 different, or to the following general formula

*COOH

H40O0C-CH [(CH -COO] H (II) 2 ml 2 n m

HO-P=O

I

OH

in which m 0 or 1 and n 1 or 2, with alcohols corresponding to the following general formula

R

3 -OH (III) in which R 3 represents straight-chain or branched C 4

-C

1 4 alkyl radicals, in a molar ratio of from 1 1 to 1 p being the valency of the phosphonoalkanecarboxylic acid corresponding

MMM

to general formula or (II), or mixtures of such reaction products for the extraction of metal ions from acidic aqueous solutions using organic solvents.

0 @000 0 *0009: 0 0 so 0 -1 Patent Application D 7604 HENKEL KGaA ZR-FE/Patente 6.1.1987 The use of phosphonoalkanecarboxylic acid partial esters for the extraction of metals

S

1 This invention relates to the use of phosphonoalkanecarboxylic acid partial esters and mixtures thereof for the 0ooo extraction of metals.

0 The ability of certain phosphonoalkanecarboxylic acids 5 to function as complexing agents for different metal ions has long been known from the prior art. In particular, 0. phosphonoalkanecarboxylic acids which have a geminal 0 phosphonate/carboxylate structure, i.e. which contain a phosphonate group ard a carboxylate group at a carbon atom S 10 of the central alkyl or alkylene chain, have been recognized oooo as good complexing agents, The metal ions which can be complexed with phosphonoalkanecarboxylic acids of this type include metal ions of both the main groups and the secondary groups of the periodic system; in particular, alkaline earth metal and heavy metal ions are complexed by phosphonoalkanecarboxylic acids.

By virtue of their good complexing power, therefore, phosphonoalkanecarboxylic acids are mainly used in special branches of industry. For example, l,1-diphosphonopropane- 2,3-dicarboxylic acid is used as a vehicle for Technetium 99 (99Tc) in skeletal scintigraphy, while 2-phosphonobutane- 1,2,4-tricarboxylic acid is used as a sequestering and threshold agent.

Compounds which form stable complexes with metals may be used for the extraction of those metals from aqueous solutions providing the metal complexes can be removed from r. -2- 1 the aqueous solution via a distribution equilibrium in the course of an extraction process. Apolar organic solvents or solvent mixtures are normally used for this purpose.

The determining factor for the velocity and completeness of the extraction process is the solubility of the aggregates of metal ion and complexing agent in the extraction solvent.

On acount of their polarity, phosphonoalkanecarboxylic acids are known to be poorly soluble in the organic solvents used for extraction.

**ooo* o* 10 However, there are references in the prior-art literature to defined esters of phosphonoalkanecarboxylic acids of o* ^^,which the solubility in organic solvents is satisfactory, but which on the other hand also have sufficient ability 0 to complex certain metal ions and which are therefore suitable for the extraction of certain metal ions from aqueous solutions)., 13 sluton~ 1 ~6q7 I3ceA ,Thus, JP-A 4 j and JP-A 6 .54= (Sakai Chemical Industries describe defined triesters of 2-phosphono-

S

butane-1,2,4-tricarboxylic acid esterified at the carboxyl groups which are capable of extracting certain metal ions to a high percentage from acidic aqueous solutions using organic solvents, The problem and, hence, the disadvantage of the extraction process described in the publications cited above is the fact that only the carboxylic acid full esters, of which the specific production and separation from the reaction mixtures used for production are extremely problematical and involve high synthesis costs, can be used for extraction; the esterification reaction designed to obtain high yields of a carboxylic acid full ester without esterification of the phosphonate groups, which is known per se and which is simple in terms of the process involved, does not achieve the desired objective for an economically reasonable outlay on starting materials and intermediate purification steps.

The object of the present invention was to provide 3 1 chemically readily accessible compounds with which certain metal ions may be extracted from acidic aqueous solutions simply and in high yields. Preference was to be attributed to those compounds and their use as extractants for certain metal ions which showed excellent dissolving properties in organic solvents and good complexing power for different metal ions.

The present invention relates to the use of reaction O. products of phosphonoalkanecarboxylic acids corresponding 10 to the following general formula SR

COOH

I I H-C CH-R

(I)

HO-P=O

OH

1 2 in which R represents COOH or PO 3

H

2 and R represents CH2COOH or PO3H2, with the proviso that R and R 2 are different, 20 or to the following general formula

COOH

H,{OOC-CH2 (CH2)n-COO] mH (II)

*HO-P=O

OH

R

3 -OH (III) in which R represents linear or branched C 4 -C14 alkyl radicals, in a molar ratio of from I 1 to I where p is 4 86 0 o a~, 00 09

S'

S

*5

S

.5i 5 1 the valency of the phosphonoalkanecarboxylic acids corresponding to general formula or or mixtures of such reaction products for the extraction of metal ions from acidic aqueous solutions using organic solvents.

The reaction products of phosphonoalkanecarboxylic acids corresponding to general formula or (II) with alcohols corresponding to general formula (III) which are used in accordance with the invention are produced by methods known per se for the esterification of acids with alcohols. These methods comprise reacting the phosphonoalkanecarboxylic acids corresponding to general formula or (II) with the alcohols corresponding to general formula (III) in the presence or absence of a solvent at elevated temperature and optionally under elevated pressure; if desired, the 15 reaction may even be carried out under an inert gas. The elevated temperatures are normally in the range from to the boiling point of the solvent used or where the reaction i s carried out in the absence of a solvent from 0 C to the boiling point of the reactants involved.

20 Where the reaction is carried out in the presence of a solvent, the solvent used may be any one of the solvents normally used for an esterification reaction. Such solvents are, for example, aromatic hydrocarbons, such as benzene, toluene, o-xylene, m-xylene or p-xylene, aliphatic hydrocarbons, such as for example hexane, heptane, octane or branched isomers thereof, or halogenated hydrocarbons, such as for example chlorobenzene, carbontetrachloride, chloroform or chlorinated ethanes. The solvents preferably used for the esterification reaction are solvents of the type capable of acting as "entraining agents" for the water formed during the esterification reaction. The xylenes mentioned above for example are known and suitable as such solvents The esterification reaction is normally carried out in a reaction vessel which enables the water formed during the esterification reaction to be removed from tho reaction r c-I ~1 5 *S

S

S..

OSO

'3

S*

S S S S 5 6* 1 via a water separator. This also enables the progress of the reaction to be accurately monitored from the quantity of water separated off. The esterification reaction may even be carried out in the presence of an acidic catalyst of the type generally known for such reactions. Suitable acidic catalysts are, for example, inorganic mineral acids, organic acids, such as aromatic sulfonic acids for example, or even so-called Lewis acids. Lewis acids, such as boron trifluoride for example, are also known for this 10 purpose from the prior art.

According to the invention, reaction products of phosphonoalkanecarboxylic acids corresponding to general formula or (II) above with alcohols corresponding to general formula (III) are used for the extraction of metals.

In one preferred embodiment, reaction products of phosphonoalkanecarboxylic acids corresponding to general formula with alcohols corresponding to general for7mula (III) or mixtures of such reaction products are used or this purpose, particular preference being attributed to those reaction 20 products or mixtures thereof in which 1,2-diphosphonoethane- 1,2-dicarboxylic acid (PEDC) is used as the phosphonoalkanecarboxylic acid corresponding to general formula Another preferred embodiment is characterized by the use of reaction products of phphophonoalkanecarboxylic acids corresponding to general formula (I1) .ith alcohols corresponding to general formul (III) or mixtures of such reaction products, particular preference being attributed to those uses of these reaction products (or mixtures thereof) in which 2-phosphonobutane- ,2,4-tricarboxylic acid (PBTC) is used.

In addition to the reaction products of the two particularly preferred phosphonoalkanecarbeoylic acids corresponding to general formula or (IX) above, however, It is also possible to use reaction products of other phosphonoalkanecarboxylic acids corresponding to general 6- 1 formula or (II) wi<' alcohols corresponding to general formula (III).

Suitable reaction products of phosphonoalkanecarboxylic acids corresponding to general formula with alcohols corresponding to general formula (III) are, for example, reaction products of 1-phosphonopropane-l,2,3-tricarboxylic acid R =COOH; R =CH2-COOH) or of 1,1-diphosphonopropane- 2,3-dicarboxylic acid R =PO R2=CH2-COOH) with S* *2R 2 alcohols corresponding to general formula (III) or mixtures 10 of these reaction products.

According to the invention, it is also possible to use reaction products of phosphonoacetic acid (II; m 0) or of 2-phosphonopropane-1,2,3-tricarboxylic acid (II; m 1, n 1) with alcohols corresponding to general formula (III) or mixtures of these reaction products as the reaction products of phosphonoalkanecarboxylic acids corresponding to general formula (II) with alcohols corresponding to general formula (III).

With regard to the use of the reaction products with the extraction of metals, particular preference is attributed to those reaction products which are formed from one of the above-mentioned phosphonoalkanecarboxylic acids corresponding to general formula or (II) with alcohols corresponding to the following general formula R 3-OH (III) in which R 3 is preferably a branch 4 C 4 -C14 alkyl radical, unless mixtures of such reaction products are used. Within the above-mentioned group of reaction products, particular preference is attributed to those emanating from the reaction of phosphonoalkanecarboxylic acids corresponding to general formula or (II) with alcohols corresponding to general formula (III), in which R is a branched C 6

-C

8 alkyi radical. Accordingly, among the branched alkyl radicals 4

S

4S gq

OS..

*5S

S

5555, *5555e *r *5 .i 56 r

OS

7 1 from the group comprising butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl and tetradecyl, particular preference is attributed to those branched alkyl radical- which emanate from the group comprising hexyl, heptyl and octyl. Of the large number of these branched isomers, 2-ethylhexyl is particularly preferred. Reaction products of phosphonoalkanecarboxylic acids corresponding to general formula or (II) with alcohols corresponding to general formula (III), in which R 3 represents 2-ethylhexyl, are used with particular advantage and with very good effect for the purposes of the present invention. This is because reaction products such as these show excellent solubility in the organic solvents used for extraction and have a high complexing power for a number of metal ions which are to 15 be separated from acidic aqueous solutions, According to the invention, reaction products of phosphonoalkanecarboxylic acids with alcohols corresponding to the above general formulae which are obtained by reaction of the acids with the alcohols in a molar ratio of from 20 1 1 to 1 where p is the valency of the phosphonoalkanecarboxylic acids corresponding to general formulae and are generally used unless mixtures of such reaction products are used. The "valency" of the phosphonoalkanecarboxylic acids corresponding to the above general formulae is understood to be the number of acid protons of the esterifiable carboxyl groups and phosphonic acid groups of the phosphonoalkanecarboxylic acids. For example, the valency (as defined above) of the particularly preferred 1,2-diphoph honoethane-1,2-dicarboxylic acid is 6, 2 acid protons having to be assigned to each of the 2 phosphonic acid groups and 1 acid proton to each of the 2 carboxylic acid groups. The same also applies to the other suitable phosphonoalkanecarboxylic acids corresponding to general formulae and For the PEDC just described, therefore, the molar ratio of phosphonoalkane- 0" 8 1 carboxylic acid to alcohol corresponding to general formula S(III) in the reaction to form the reaction products useable in accordance with the invention may be in the range from 1 1 to 1 5.5. For the phosphonoalkanecarboxylic acids having a lower valency p (as defined above), the upper limit to the molar ratio for the formation of the reaction products is thus correspondingly lower and depends upon the number of acidic groups available for an esterification reaction.

Preferred embodiments of the invention are characterized by the use of reaction products of phosphonoalkanecarboxylic acids corresponding to general formula or (II) with alcohols corresponding to general formula (III), in the production of which by esterification the molar ratio of acid to alcohol is from 1 2 to 1 (q 1.5) and more preferably in the range from 1 2 to 1 (q where q is a valency of certain phosphonoalkanecarboxylic acids from the above-mentioned group of greater than or equal to 4. In analogy to the use described above, mixtures of such reaction products may of course also be used. According to the invention, therefore, it is preferred to use reaction products of phosphonoalkanecarboxylic acids (such as PEDC *o for xsample) with alcohols corresponding to general formula (III), in the production of which by esterification (for the example of PEDC) the molar ratio of acid to alcohol is from 1 2 to 1 4.5 and more preferably in the range from 1 2 to 1 4; as described above, the valency of PEDC as g* defined above is 6. Mixtures of such reaction products of PEDC with alcohols corresponding to general formula (IlI) may of course also be used in this example.

According to the invention, the reaction products described above, which may be broadly described as partial esters of the phosphonoalkanecarboxylic acids corresponding to general formula or may be used for the extraction 39 of a number of metal ions from acidic aqueous solutions. It a 9 1 has surprisingly been found that the use of the partial esters produces particularly good results where ions of alkaline earth metea or heavy metals are to be extracted from acidic aqueous solutions. According to the invention, particularly good results may be obtained in the extraction from acidic aqueous solutions of metal ions emanating from the group comprising iron, cobalt, nickel, copper, zinc, antimony and bismuth. The best results were surprisingly obtained for iron, antimony and bismuth ions. It was found on the one hand that these ions could be extracted to a very high percentage from the acidic aqueous solutions in question and, on the other hand, that even very small amounts of these ions could be extracted from acidic aqueous solutions when these small amounts were present in addition to large amounts of other ions in the acidic aqueous solution to be extracted. This demonstrates a high specificity of the partial esters of the above-described phosphonoalkanecarboxylic acids for the extraction of these particUlar heavy metal ions.

2 The pH-values of the acidic aqueous solutions to be $00 extracted may vary over a large part of the acidic pH value range. It is emphasized that the use of the phosphonoalkanecarboxylic acid partial esters can lead to a particularly high specificity for the extraction of a certain metal ion if a certain pH value is maintained during the extr S process. Overall, the pH value of the aqueous solution be extracted may vary over a range of from 0 to 7. Certain% metal ions may be better extracted, for example, at a pH value in the range from 0 to 1.5 (for example antimony and bismuth *"*oand also iron). By contrast, other ions, such as for example cobalt, nickel or zinc, may be extracted at higher pH values, for example at a pit value of 3, using the phosphonoalkanecarboxylic acid partial esters according to the invention, Using the reaction products of the phosphonoalkandcarboxylic acids corresponding to general formulae and 10 1 (II) with alcohols corresponding to general formula (III) or mixtures thereof in accordance with the invention, it is possible to extract the metal ions with the aid of organic solvents. The organic solvents in question are known per se from the prior art for the extraction of metals. Preference is attributed to organic solvents or mixtures thereof from the group comprising linear and branched C 6

-C

12 alkanes and alkenes, aromatic hydrocarbons and halogenated hydrocarbons, among which solvent mixtures of different C -C12 10 alkanes liquid at room temperature are preferred. Solvent mixtures such as these are commercially available and are

(R)

marketed, for example, under the names Solvesso and Escaid (R) The invention is illustrated by the following Examples.

EXAMPLE 1 Preparation of a reaction p-oduct of a phosphonoalkanecarboxylic acid corresponding to general formula with an alcohol corresponding to general formula (III), 1 mole 1,2-diphosphonoethane-l,2-dicarboxylic acid dihydrate was suspended in 100 ml xylene and 4 moles ethyl hexanol added to the resulting suspension. The mixture was heated to 150 0 C and the water of hydration or rather reaction eliminated was continuously removed from the reaction via a water separator. After 7 to 8 h, the calculated quantity oI water (6 moles) had been separated off, Approximately 1 mole 1,2-diphosphonoethane-1,2-dicarboxylic acid tetrakis- (2-ethylhexylester) was obtained, Acid number 145 (calculated 155)i Where n-octanol was used as the alcohol corresponding to general formula (III), the same reaction produced the corresponding 1,2-diphosphcnoethane-1,2-dicarboxylic acid tetrakis- (2-n-octylester).

Where 5 moles ethyl hexanol werei used, the same reaction produced the corresponding 1,2-diphosphonoethane-1,2- II 1.

11 1 dicarboxylic acid penta-(2-ethylhexylester); where 6 moles ethyl hexanol were used, the corresponding hexa-(2-ethylhexylester) unuseable for the purposes of the invention was formed (see Comparison Example 1).

EXAMPLE 2 Preparation of a reaction product of a phosphonoalkanecarboxylic acid corresponding to general formula (II) with S. an alcohol corresponding to general formula (III) 10 1 mole of an 87% aqueous solution of 2-phosphonobutane- 1,2,4-tricarboxylic acid (PBTC) was heated to 70 0 C. 2

ISBN

0 moles ethyl hexanol were then added dropwise with vigorous 6600 stirring. The reaction mixture was kept at 70 0 C for 500006 23 hours.

The acid number of the reaction mixture obtained was 0 0255 (calculated: 295). According to NMR spectroscopy, of the 2-phosphonobutane-1,2,4-tricarboxylic acid-bis-(2ethylhexylester) formed during the reaction was present as dicarboxylate (esterification at two carboxylic acid groups), 14% as geminal monophosphonate carboxylate (esterification of one phosphonate group and one carboxylate group attached to carbon atom 2) and 6% as diphosphonate (esterification of both phosphonate groups), COrresponding mono-, tri- or tetraesters of 2-phosphonobutane-1,2,4-tricarboxylic acid may be obtained in exactly the same way by variation of the molar ratio of phosphonocarboxylic acid to alcohol.

A full ester (pentaeester) of PBTC was obtained by exactly the same reaction of the phosphonoalkanecarboxylic acid with 2-ethyl hexanol in a molar ratio of 1 1 and subsequent reaction with a large excess of methanol; the 2-phosphonobutane-1, 2, 4-tricarboxylic acid (2-ethylhexyl)tetramethyl ester was formed (Comparison Example 2).

Other corresponding esters of PETC may also be prepared by variation of the alcohols.

-11 12 1 Partial esters and full esters of other phosphonoalkanecarboxylic acids corresponding to general formulae and (II) above were prepared in exactly the same way.

The solutions containing metal ions used for the following Examples of solvent extraction were prepared by dissolving metal sulfates in water. The pH value required for the extraction was subsequently adjusted by addition of

H

2

SO

4 1 rThe following aqueous electrolyte solutions were t oo*: 10 prepared: Solution 06SS ease copper content: 2.0 g/l Osseo: nickel content: 2.9 g/l cobalt conLent: 3.0 g/l "s zinc content: 3.3 g/l and *l iron content: 2,8 g/l.

The pH values for the extraction of the individual metal ions were as follows: pH 1.5 for the extraction of copper and iron and pH 3.0 for tho extraction of nickel, cobalt and zinc.

H• SO.

Solution iron contentk 2.0 g/l antimony content:0.3 to 0.5 g/l and bismuth content: 0.3 to 0.5 g/l.

Total sulfuric acid content: 180 to 250 g/l.

The acidic, aqueous electrolyte solutions having the compositions indicated above were contacted with 0.1 M solutions of the partial esters of phosphonoalkanecarboxylic acid. indicated in the followng Examples in organic solvents, the ratio by volume of orgaic phase to inorganic phase being 1 1 in every case. Extraction was carried out in a singleit 13 1 stage shaking test; the shaking time was 1 hour at room temperature. The results of the extraction tests are shown in the following Table, the extraction values of the individual metal ions being shown in percent, based on the starting content of metal ions in the above-mentioned electrolyte solutions and EXAMPLE 3 go* Extraction with partial esters of 1,2-diphosphonoethane- 10 1,2-dicarboxylic acid (PEDC) a) Extraction with PEDC tetra-(n-octylester); organic solvent: Escaid (R)100.

oe b) Extraction with PEDC tetra-(2-ethylhexylester); solvent: *ee *Escaid 100.

c) Extraction with PEDC penta-(2-ethylhexylester); solvent: Escaid 100.

COMPARISON EXAMPLE 1 a) Extraction with PEDC hexa-(2-ethylhexylester); solvent: 20 Escaid( 100., b) Extraction with PEDC tetra-(n-dodecylester) solvent: Escaid(R) 00.

'**The results of the extraction tests are shown in Table 1, below.

1 ri 14 1 Table 1 Extraction with partial esters of PEDC Extraction of (in so a.

S

oo..o a. 0006 0 O000

S

S.

0S S Ge *5 S. S so

S

Be *5* Solution Solution (b) Example Cu Ni Co Zn Fe Fe Bi Sb 3a Pl) P1) 67 Pl) 85 68 62 67 3b 100 57 67 73 100 67 100 88 30 50 27 33 46 71 35 10 52 10 'Comp. 2a 10 13 7 19 42 10 0 0 Comp. lb Emulsion formation Emulsion formation Note: 1) p precipitation Result As can be seen from Table 1, the tetra-(2-ethylhexylester) of PEDC (Example 3b) shows optimal extraction behavior; the extraction capacity of the corresponding pentaester (Example 3c) is distinctly lower while the full ester (hexaester; Comparison Example la) shows inadequate extraction behavior. Mixtures of the particular esters esterified at the various possible acidic groups were used in every case, According to Example partial esters formed from the reaction of phosphonoalkane carboxylic acid with straightchain alkyl radicals show distinctly poorer extraction behavior than branched-chain reaction products. Undesirable precipitation and emulsion formation were observed, being caused by the inadequate solubility of the partial ester itself or of its metal compexes.

EXAMPLE 4 Partial esters of 2- phosphonobutane-1,2,4-tricarboxylic acid (PBTC): a) PBTC mono-(n-hexylester); solvent: kerosine 15 1 b) PBTC mono-(2-ethylhexylester); solvent: kerosine c) PBTC di-(n-hexylester); solvent: Solvesso(R) 150/10 by volume i-decanol

(R)

d) PBTC di- (2-ethyhexylester) solvent: Solvesso (150.

COMPARISON EXAMPLE 2 Extraction with PBTC mono-(2-ethylhexyl)-tetramethyl ester (full ester) solvent: Solvesso (R)150.

The results of the extraction tests are shown in 10 Table 2 below, me eg 0 ~Z 0 eggs

S

5 Be S

CS

C

e

S

5.1

S

Table 2 Extraction with partial esters of PBTC Extraction of (in Solution (a) Cu Ni Co Solution (b) Fe Bi Sb Example Zn Fe 4a Partial ester insoluble in kerosine 20 4b Partial ester insoluble in kerosine 4c 25 19 10 19 83 32 35 88 4d 35 23 27 27 83 25 14 74 Comp. 2 0 0 3 0 8 No extraction Result Diesters of PBTC show good extraction behavior both in strongly acidic and in normally acidic aqueous solution, the extraction behavior of the diester containing a branched

C

8 group being better than that of the unbranched derivative.

The 1 1 reaction products are unsuitable for extraction because they are insoluble in the organic solvent. The full ester of PBTC (Comparison Example 2) does not extract at all in strongly acidic solution and only unsatisfactorily in moderately acidic solution.

*Ic _11C i 16 a a 0 0 1 EXAMPLE Extraction with other partial esters of phosphonoalkanecarboxylic acids a) 1,1-diphosphonopropane-2,3-dicarboxylic acid (DPD) tri- (2-ethylhexylester); solvent: Escaid(R) 100.

b) Phosphonoacetic acid (PESE) mono-(2-ethylhexylester); solvent: Solvesso(R) 150/10 by volume i-decanol.

c) Phosphonoacetic acid di-(2-ethylhexylester) solvent:

(R)

Escaid 100.

COMPARISON EXAMPLE 3 Extraction with 1-phosphonopropane-l,2,3-tricarboxylic acid penta-(2-ethylhexylester) (full ester of PPTC).

The results of extraction with the esters of Example and Comparison Example 3 are shown in Table 3 below.

Table 3 Extraction with partial esters of DPD and PESE Extraction of (in Solution (a) Example Cu Ni Co Solution Fe Bi Zn Fe 72 55 67 67 100 100 61 23 6 7 21 P1) p1) 20 10 13 41 64 70 0 0 Comp. 3 0 0 0 15 32 5 0 29 Note: 1) P precipitation

Claims

1. The use of reaction products of phosphonoalkanecarboxylic acids corresponding to the following general formula R COOH 1 1

2 H-C CH-R (1) I HO-P=O OH 9e OS 0 12 2 in which R represents COOH or PO H and R represents

3. 2 1 2 CH 2 COOH or P0 3 H 2 with the proviso that R and R are 0 64 different, we*@or to the following general formula sees*: S: COOH HOOC-CH 2 (CH 2 -COO) (II) 2*M 2 n m ii .HO-P O I OH 9 S.,.Ur inwhichm 0 or 1 and n= 1 or 2, with alcohols corresponding to the following general formula a 3 7 R 3_OH (IXI) in which R is a linear or branched C 4 -C1 4 alkyl radical, in a molar ratio of from 1 1 to 1 where p is the valency of the phosphonoalkanecarboxylic acids corres- ponding to general formula or (It)I or of mixtures of such reaction products for the extraction luna C c 6a 7 of metal ions from a&c-ked-o queous solutions)using organic solvents. 2. The use claimed in Claim 1, characterized in that reaction products of phosphonoalkanecarboxylic acids corresponding to general formula with alcohols corres- ponding to general formula (1t1) or mixtures of such To iv7 O~ 18 reaction products are used. 3. The use claimed in Claim 2, characterized in that reaction products of 1,2-diphosphonoethane-l,2-dicarboxylic acid with alcohols corresponding to general formula (III) or mixtures of such reaction products are used.

4. The use claimed in Claim 1, characterized in that reaction products of phosphonoalkanecarboxylic acids corresponding to general formula (II) with alcohols S* corresponding to general formula (III) or mixtures of such reaction products are used.

The use claimed in Claim 4, characterized in that reaction products of 2-phosphonobutane-1,2,4-tricarboxylic acid with alcohols corresponding to general formula (III) or mixtures of such reaction products are used.

6. The use claimed in Claims 1 to 5, characterized in that reaction products of phosphonoalkanecarboxylic acids with alcohols corresponding to general formula (III) in which R 3 represents branched C 4 -C1 4 alkyl radicals, or mixtures of such reaction products are used.

7. The use claimed in Claim 6, characterized in that reaction, products of phosphonoalkanecarboxylic acids with alcohols corresponding to general formula (III), in which S*R represents branched C 6 -C 8 alkyl radicals, or mixtures of such reaction products are used.

8. The use claimed in Claims 6 and 7, characterized in that reaction products of phosphonoalkanecarboxylic acids with alcohols corresponding to general formula (III), in which R 3 represents a 2-ethylhexyl radical, or mixtures of such reaction products are used.

9. The use claimed in Claims 1 to 8, characterized in that reaction products of phosphonoalkanecarboxylic acids with alcohols in a molar ratio of from 1 2 to 1 and preferably in a molar ratio of fron I 2 to 1 where q is the valency 4 of the phosphonoalkanecarboxylic acids corresponding to general formula or or I Aersnsbace /-oakirdclo itrso 0 'I 19 mixtures of such reaction products are used.

The use claimed in Claims 1 to 9, characterized in that the reaction products of phosphonoalkanecarboxylic acids with alcohols are used for the extraction of metal ions from the group of alkaline earth metals and heavy metals.

11. The use claimed in Claim 10, characterized in that the reaction products are used for the extraction of metal ions from the group comprising iron, cobalt, nickel, copper, zinc, antimony and bismuth. *sees: 4

12. The use claimed in Claims 1 to 11, characterized in that the pH values of the acidic aqueous solutions for the extraction of the metal ions are in the range from 0 to 7.

13. The use claimed in Claims 1 to 12, characterized in that the organic solvents used are solvents from the group comprising straight-chain and branched-chain C 6 -C 12 alkanes and alkenes, aromatic hydrocarbons and halogenated hydro- ""carbons or mixtures thereof.

14. A process for extraction of metals substantially as fs: hereinbefore described with reference to any one of the examples. Metals extracted by a process as claimed in any one of see claims 1 to 14. 'I DATED this THIRTY FIRST day of DECEMBER 1987 Henkel Kommanditbgesellschaft auf Aktien Patent Attorneys for the Applicant SPRUSON FERGUSON D 7604 RT/EN