CA1083828A

CA1083828A - Extraction of copper values from aqueous solutions with hydroxy-oximes

Info

Publication number: CA1083828A
Application number: CA245,976A
Authority: CA
Inventors: Robert Taylor; Abraham J. Van Der Zeeuw
Original assignee: Shell Canada Ltd
Current assignee: Shell Canada Ltd
Priority date: 1975-03-26
Filing date: 1976-02-17
Publication date: 1980-08-19
Also published as: DE2612505C2; SU843768A3; GB1537828A; JPS51119614A; DE2612505A1; AU1232076A; YU60176A; JPS5933651B2; AU498391B2; BE839961A; PL105481B1; ZM3176A1; ZA761803B; YU41560B

Abstract

ABSTRACT

A process is described for the separation of copper values from an acidic aqueous solution thereof by liquid-liquid extraction with an extractant comprising an organic solvent and a dissolved hydroxy-oxime. The process utilizes a known hydroxy oxime of the general formula A- C(=NOH) - R, (I) in which R represents a hydrogen atom or an aliphatic group and A an aromatic group carrying as substituents a hydroxyl group at a ring carbon atom in a 2-position-the number 1 being assigned to the ring carbon atom to which the -C(=NOH)-R group is attached- and optionally an organic group D, and/or (2) a known 2-hydroxybenzophenone oxime substituted by a saturated or ethylenical-ly unsaturated aliphatic group or groups or the corresponding ether group or groups in combination with (a) hydrocarbyl hydroxymethyl ketone oxime, (b) 2-hydroxyaldoxime in which the carbon atom carrying the hydroxyl group also carries two hydrocarbyl groups or one hydrocarbyl group and one hydrogen atom, (c) 2-hydroxycycloalkanone oxime in which the cycloaliphatic ring also carries one or more organic groups or aliphatic alpha-hydroxy-oxime of the general formula

Description

The invention relates to a process for the separation of copper values rrom an acidic aqueous solution thereof by liquid-liquid extraction with an extractant comprising an organi.c solvent and a dissolved hydroxy-oxime and to novel oximes. Oxime extractants are known from:
(A) British patent specification 1,322,532, disclosing the use of a hydroxy-oxime of the general formula : A-C(=NOH)-R, in which R represents an aliphatic group and A a cyclic organic group carrying as substituents at least a hydroxyl group at a ring carbon atom in a 2-position ` - the number 1 being assigned to the ring carbon atom to which the -C(=NOH)-R group is attached - and an . organic group D, ; 15 (B) U.S. patent specification 3,428,449, disclosing ' the use of a 2-hydroxybenzophenone oxime substituted s by a saturated or ethylenically unsaturated aliphatic group or groups or the corresponding ether group or : groups, and (C) German Offenlegungsschrift 2,334,901, disclosing the use of a salicylaldoxime of the general formula : H
~ in which all symbols R - which may be the same or - different - represent a halogen atom or a nitro, . , , .

, cyano, primary amino, secondary amino, tertiary amino, alkyl, alkenyl, cycloalkyl, aryl, aralkyl, alkoxy, aryloxy, aralkoxy or acyloxy group or a substituted derivative thereof, n is an integer from 1 to 4 inclusive and which aldoxime contains in total at least three carbon atoms in the alkyl group(s) R.
The extraction can be conducted continuously by bringing the acidic aqueous solution into contact with a solution of the hydroxy-oxime in, for example, kerosine, preferably by vigorous stirring. Then, the organic phase is separated from the aqueous phase and stripped with an aqueous solution containing a strong acid. The copper values are thus transferred to the aqueous stripping solution as copper salts and can then be recovered, for example, by crystalli%ation, ~ -.. . .
or as copper by electrolysis, while the organic phase containing the released hydroxy-oxime is advantageously used again for subsequent copper extractions. The - extraction is very suitable for the separation of ~ ~-copper values from iron values.
U.S. patent specification 3,428,449 discloses that the use of the 2-hydroxybenzophenone oximes stated sub(B) in combination with aliphatic alpha-hydroxy-oximes i of the general formula OH NOH
R1 _ C - C - R2 ~' ~0838Z8 in which Rl, R2 and R3 may be any of a variety of organlc radicals such as aliphatic and alkylaryl radicals, whilè R3 may also represent a hydrogen atom, results in an improvement in the rate of the copper extraction.
It has now been found that this improvement is also achieved, and sometimes to a greater extent, with other combinations of oximes.
The present invention provides a process for the separation of copper values from an acidic aqueous solution thereof by liquid-liquid extraction with an extractant comprising an organic solvent, and dissolved therein (1) a hydroxyoxime of the general formula A - C(=NOH) - R (I) in which R represents a hydrogen atom or an aliphatic group and A an aromatic group carrying as substituents a hydroxyl group at a ring carbon atom in a

2-position, the number 1 being assigned to the ring carbon atom to which the -C(=NOH)-R group is attached, and optionally at least one organic group D, and/or (2) a 2-hydroxybenzophenone oxime substituted by a saturated or ethylenically unsaturated aliphatic group or groups or the corresponding ether group or groups, in combination with a dissolved (a) hydrocarbyl hydroxymethyl ketone oxime, (b) 2-hydroxyaldoxime in which the ~rbon atom carrying the hydroxyl group also carries two hydrocarbyl groups or one hydrocarbyl group and one hydrogen atom, (c) 2-hydroxycycloalkanone oxime in which the cycloaliphatic ring also carries at least..one organic group, or (d) aliphatic alpha-hydroxy-oxime of the general formula OH NOH
Rl _ C - C - R2 (II) in..which Rl, R2 and.R3 each represent an organic group and R3 may also represent a hydrogen atom with the proviso that an aliphatic alpha-hydroxy-oxime of the general formula II is present only whenever a hydroxyoxime of the general formula I is also present.

The process according to the present invention has a considerable synergistic effect - compared with the use of the oximes stated sub (1) and (2) in the absence of those sub (a), (b), (c) and (d) - on the extraction rate, which has very favourable economic con-sequences. There is hardly any unfavourable effect, if at all, on the selectivity of the e~traction with respect to iron, so that aqueous solutions also containing iron values are very suitable starting solutions. me acidic aqueous ~;
solution preferably has a pH between O and 3.
me molar percentage in which the oximes stated -sub (a), (b), (c) and/or (d) - calculated on the oximes ~ -stated sub (1) and/or (2) - are applied is not critical.
me molar percentage which can best be applied can easily -~.
be established by means of simple extraction ~ ~

.: :

iO83828 experiments, in which this percentage is increased, starting from, say, 0.1. The best percentage is that at which the extraction rate has reached a constant level. This percentage will nearly always be between 1 and 100. Preference will be given to percentages between 2 and 20 and particularly between 4 and 12.
The hydrocarbyl group in the hydrocarbyl hydroxymethyl ketone oxime may be, for example, an alkyl, aromatic or a cycloalkyl group, whether or not substituted or containing hetero atoms. Very good results have been obtained with hydrocarbyl hydroxymethyl ketone oximes possessing an alkyl group, particularly with alkyl hydroxymethyl ketone oximes and alkylphenyl hydroxymethyl ketone oximes; the extraction rates achieved with application of each of these two groups of oximes in the process of the -nvention are usually - higher than those obtained with a mixture of oximes used according to U.S. patent specification 3,428,449.
The number of carbon atoms in the alkyl groups is preferably larger than five. Excellent results have been obtained with n-dodecyl hydroxymethyl ketone oxime and p-n-decylphenyl hydroxymethyl ketone oxime.
Other examples of such oximes are p-n-dodecylphenyl hydroxymethyl ketone oxime, p-n-nonylphenyl hydroxymethyl ketone oxime, p-tert-nonylphenyl hydroxymethyl ketone ; oxime, n-nonyl hydroxymethyl ketone oxime, 2-methylnonyl hydroxymethyl ketone oxime and p-n-decylbenzyl hydroxymethyl ketone oxime.

:, ~, 1~8382~3 The hydrocarbyl groups present in the 2-hydroxy-aldoximes stated sub (b) are, for example, alkyl, alkenyl, aromatic or cycloalkyl groups. The presence Or substituents or heteroatoms - for example, oxygen atoms - in these hydrocarbyl groups is not precluded. The 2-hydroxyaldoximes are preferably 2-hydroxyalkanal oximes, in particular those with eight to 20 carbon atoms per molecule.
Particularly high extraction rates have been achieved with 2-hydroxy-2-methylpentadecanal oxime, 2-hexyl-2-hydroxy-decanal oxime and 2-hydroxy-2-pentylnonanal oxime.
Other examples of these oximes are 2-hydroxy-2-methyltetradecanal oxime, 2-ethyl-2-hydroxydodecanal oxime, 2-butyl-2-hydroxydecanal oxime, 2-hydroxy-2-pentyldecanal oxime and 2-hydroxy-2- ~ -1~ pentylundecanal oxime.
I ~I5 The organic group or groups attached to the cycloaliphatic - ring of the 2-hydroxycycloalkanone ;oxime stated sub (c) may be, for example, aromatic, cycloaliphatic, ,~ alkenyl or - what is preferred - alkyl groups. The presence of substituents or hetero atoms, for example, oxygen atoms, in the:;e hydrocarbyl groups is not precluded.
2-Hydroxycyclododecanone oximes, particularly those in which the ring carries one or more alkyl groups are preferred. Very high extraction rates have been achieved with ~-alkyl-2-hydroxycyclododecanone oximes, particularly with 2-hydroxy-2-methylcyclododecanone oxime and 2-hydroxy-2,6,10-trimethylcyclododecanone oxlme. Other examples of theee 2-hydroxycycloalkanone ,~,~....

1083~g28 oximes are 2-hydroxy-4-nonylcycloheXanone oxime, 4-d~Jdecyl-2-hydroxy-cyclohexanone oxime, 2-hydroxy-3-methylcyclododeca-none oxime, 2-ethyl-2-hydroxycyclododecanone oxime, 2,6,10-triethyl-2-hydroxycyclododecanone oxime and 2-hydroxy-6-nonylcyclododecanone oxime.
R , R2 and R3 in the general formula II may each represent, for example, an aromatic, a cycloaliphatic or an alkyl group. The presence of substituents or hetero atoms, for example, oxygen atoms, is not precluded.
R1 and R2 preferably represent branched alkyl groups or unsaturated hydrocarbyl groups, containing from six to 20 carbon atoms. R1 and R2 are preferably the same; when these are alkyl groups, they are preferably secondary alkyl groups. R3 preferably represents a hydrogen atom. High extraction rates have been achieved with 5,8-diethyl-7-hydroxy-6-dodecanone oxime. Other ; examples of compounds of the general formula II are 8-hydroxy-7-tetradecanone oxime and 6,9-diethyl-7-hydroxy-8-tetradecanone oxime .
The aromatic group A in the general formula I may be carbocyclic or heterocyclic. Examples of groups A are phenyl, naphthyl, furyl and pyridyl groups.
Preference is given to a phenyl group.
The organic group or groups D atached to the aromatic group A may be, for example, alkyl, cycloalkyl, aryl, alkaryl, aralkyl, alkenyl, alkapolyenyl, alkoxy, alkylthio, aryloxy, aralkoxy or alkoxycarbonyl groups.

, Preference is given to alkyl groups. The alkyl group or groups may be straight or branched. The hydroxy-oxime of the general formula I preferably contains at least seven carbon atoms in the alkyl group(s) attached to the aromatic group A and in particular not more than 14. More generally, the number of carbon atoms in the group or groups D may range from, for example, one to 20. The number Or carbon atoms is the sum of the number of carbon atoms present in the joint alkyl groups. Examples of suitable alkyl groups D are :
ethyl, l-methylbutyl, 1-methylpentyl, 1-methylhexyl, 1-methylheptyl, 1-methyloctyl, 1-methyldecyl, 1-methyltetradecyl and tert-nonyl (a mixture of branched nonyl groups derived from propene trimer). The aromatic group A
may also carry primary amino, secondary amino and tertiary amino groups and inorganic substituents, for example, chlorine atoms and nitro groups.
An aliphatic group represented by R in the general formula I may be, for example, an alkyl, alkenyl or alkapolyenyl group. The aliphatic group R may be straight or branched and it may contain substituents - for example, a phenyl group - and/or hetero atoms - for example, an oxygen atom. A straight group has proved , very favourable as a rule. The number of carbon atoms of the group R may range, for example, from one to 20. An alkyl group is generally preferred. Examples of suitable alkyl groups are: methyl, ethyl, n-pentyl, n-heptyl, n-octyl, n-nonyl, n-undecyl, n-tridecy]
and n-heptadecyl. Methyl groups are very suitable, because they impart the highest extraction and stripping rates to the oxime. A benzyl group is also very suitable.
Examples of very suitable hydroxy-oximes are methyl 4-butyl-2-hydroxyphenyl ketone oxime, methyl 2-hydroxy-5-tert-no-nylphenyl ketone oxime, n-heptyl 2-hydroxy-5-(1-methyl-hexyl)phenyl ketone oxime, n-octyl 2-hydroxy-5-(1-methylheptyl) phenyl ketone oxime, n-nonyl 2-hydroxy-5-(1-methyloctyl)phenyl ketone oxime and n-nonyl 2-hydroxy-5-(1-methylhexyl)phenyl ketone oxime. Further examples are n-tridecyl 2-hydroxy-5-methyl-phenyl ketone oxime, methyl 2-hydroxy-5-(1-methylhexyl)phenyl ketone oxime, ethyl 2-hydroxy-5-(1-methylundecyl)phenyl ketone oxime, n-pentyl 2-hydroxy-5-(1-methyldecyl)phenyl ketone oxime, n-undecyl 2-hydroxy-5-(1-methylpentyl)phenyl ketone oxime, n-heptyl 2-hydroxy-5-(1-methyltetradecyl)phenyl ; ketone oxime, n-undecyl 2-hydroxy-5-(1-methylheptyl)phenyl ketone oxime and n-heptadecyl 2-hydroxy-5-(1-methyl-heptyl)phenyl ketone oxime. Excellent results have been obtained with methyl 2-hydroxy-5-tert-nonylphenyl ketone oxime and benzyl 2-hydroxy-5-tert-nonyl-phenyl ketone oxime. These two compounds may be prepared using as a precursor 4-tert-nonylphenol, obtained by alkylating phenol with propene trimer.
Examples of hydroxy-oximes of the general formula I in which R represents a hydrogen atom are 5-tert-butyl-2-hydroxy-benzaldoxime, 5-dodecyl-2-hydroxybenzaldoxime, 3,5-di-tert-butyl-2-hydroxybenzaldoxime, 2-hydroxy-5-octylbenzaldoxime, 2-hydroxy-3,5-di-tert-pentylbenzaldoxime, 2-hydroxy-5-tert- nonylbenzaldoxime and 2-hydroxy-3,5-di(1-methyl-butyl)benzaldoxime Very high extraction rates have been obtained with the last mentioned oxime.
; The 2-hydroxybenzophenone oximes stated sub (2) are those disclosed in U.S. Patent Specification 3,428,449.
Among these oximes those substituted in one 5-position are preferred, particularly those carrying alkyl substituents.
Very good results have been obtained with 2-hydroxy-5-tert-nonylben-zophenone oxime.
Excellent results have been obtained with the ~` following combinations of oximes: methyl 2-hydroxy-5-tert-nonyl-`-I phenyl ketone oxime with n-dodecyl hydroxymethyl ketone oxime or p-n-decylphenyl hydroxymethyl ketone oxime;
.
benzyl 2-hydroxy-5-';ert-nonylphenyl ketone oxime with ~ r~-dodecyl hydroxymethyl ketone oxime or 2-hydroxy-2-methylpenta-:~t~` ~ decanal oxime; 2-hydroxy-5-(1-methyloctyl)benzophenone oxime with n-dodecyl hydroxymethyl ketone oxime, 2-hydroxy-2-methylpentadecanal oxime or 2-hydroxy-2,6,10-trimethy~-cyclododecanone oxime; 2-hydroxy-3,5-di(1-methylbutyl)benzaldoxime and n-dodecyl hydroxymethyl ketone oximme.
A favourable volume ratio of the extractant to the acidic aqueous solution has been found to be 1:3 ,7~ ~
--25 ~ to 3:1. However, ratios outside this range may also be used. As a rule~ the extraction proceeds smoothly ~ between 15 and 35C. However, higher or lower temperatures, ,,1 ' .: .
,i ' . .

;:

. , ' .

for example, between 0C and 15C and 35C and 75C,are not precluded.
Preferably, the mutual miscibility of the acidic aqueous solution and the organic solvent should not exceed 5 %v, and in particular it should be lower than 1 %v. Suitable solvents are, for example, halogenated solvents, such as chlorof'rm, 1,2-dichloroethane, 1,2-dichloropropane and di(2-chloroethyl) ether, and in particular hydrocarbons, for example, kerosine, toluene and the xylenes.
2-Alkyl-2-hydroxycyclododecanone oximes in which 10 carbon atoms of the ring are unsubstituted - for example, 2-hydroxy-2-methylcyclododecanone oxime -, 2,6,10-trialkyl-2-hydroxycyclododecanone oximes in which the three alkyl groups are the same and eight carbon atoms of the ring are unsubstituted - for example, 2-hydroxy-2,6,10-trimethylcyclododecanone oxime -and 4-alkyl-2-hydroxycyclohexanone oximes - for example, 4-alkyl-2-hydroxycyclohexanone oximes in which the alkyl group has more than three carbon atoms, such as in 2-hydroxy-4-n-pentylcyclohexanone oxime - are novel compounds. The novel compounds may be prepared by reaction of the corresponding ethylenically unsaturated precursor with nitrosyl sulphuric acid, followed by reaction with water of the 2-hydroxyimino hydrogen sulphate formed.

-- ~3 --Thus, a 2-alkyl-2-hydroxycyclododecanone oxime in which 10 carbon atoms of the ring are unsubstituted is formed by reacting the corresponding 2-alkylcyclododecene with nitrosyl sulphuric acid, followed by reaction with water of the 1-alkyl-2-hydroxyiminocyclododecyl hydrogen sulphate formed. For example, 2-hydroxy-2-me-thylcyclododecanone oxime is formed by reacting 2-methylcyclodo:
decene with nitrosyl sulphuric acid, followed by reaction with water of the 1-methyl-2-hydroxyiminocyclododecyl hydrogen sulphate formed. 2,6,10-Trialkyl-2-hydroxycyclododecanone oximes in which the three alkyl groups are the same and eight carbon atoms of the ring are unsubstituted, is formed by reacting the corresponding 2,6,10-trialkyl-1-cy-clododecene with nitrosyl sulphuric acid, followed by reaction with water of the 1,5,9-trialkyl-2-hydroxyimino hydrogen sulphate formed. For example, 2-hydroxy-2,6,10-trimethyl-cyclododecanone oxime is formed by reacting 2,6,10-trimethyl-1-cy-clododecene with nitrosyl sulphuric acid, followed by reaction with water of the 1,5,9-trimethyl-2-hydroxy-imino hydrogen sulphate formed. 4-Alkyl-2-hydroxycy-clohexanone oximes - among which those in which the alkyl group has more than three carbon atoms - are formed by reacting the corresponding 4-alkyl-1-cyclohexene with nitrosyl sulphuric acid, followed by reaction with water of 5-alkyl-2-hydroxyiminocyclohexyl hydrogen sulphate formed. For example, 2-hydroxy-4-n-pentylcyclohexanone oxime is ~ormed by re~cting 4-n-pentyl-1-cyclohexene ' ' , .

with sulphuric acid, followed by reaction with water of the 5-n-pentyl-2-hydroxyiminocyclohexyl hydrogen sulphate formed.
The invention is further illustrated by means of the following examples. The extractions described in the exampleG were conducted in a separatory funnel consisting of a graduated, straight-walled vessel with a capacity of 0.25 l, equipped with a double-paddle stirrer and provided at the bottom with a stop-cock for draining. The two starting liquids were introduced via the top opening. The starting aqueous solution contained copper sulphate and ferric sulphate in concentrations Or 63 and 36 mmol/l, respectively, and so much free sulphuric acid that the pH was 1.90. The organic solvent -~ 15 was a kerosine fraction having an atmospheric boiling range from 210C to 240C. A mixture of 100 ml of the starting aqueous solution and 100 ml Or the starting organic extractant was stirred in the funnel at a temperature of 25C at a rate of 2000 rev/min. At : .:
various moments samples of the mixture being stirred ~ were taken. The two phases of the samples were separated ;~ and the percentage of the ~copper extracted, calculated on equilibrium, was determined.
The oximes belonging to groups (a), (b), (c) and (d) stated hereinbefore and used in the Examples I-IV are named in Table I and have been numbered as ~; - indicated in this table.

' ' .

, .

~083828 _ lr, _ Table I

Name of oxime Number _ n-dodecyl hydroxymethyl ketone oxime p-n-decylphenyl hydroxymethyl ketone oxime 2 2-hydroxy-2-methylpentadecanal oxime 3 2-hexyl-2-hydroxydecanal oxime 4 2-hydroxy-2-pentylnonanal oxime 5 2-hydroxy-4-pentylcyclohexanone oxime 5 2-hydroxy-2-methylcyclododecanone oxime 7 2-hydroxy-2,6,10-trimethylcyclododecanone oxime 8 5,8-diethyl-7-hydroxy-6-dodecanone oxime 9 Example I

A. Not according to the invention ____________ _________________ The kerosine fraction only contained 0.2 mol of methyl 2-hydroxy-5-tert-nonylphenyl ketone oxime per litre. This oxime was prepared by oximation of 2-hydroxy-5-tert-nonylphenyl methyl ketone with hydroxylamine.
This ketone was formed by Fries rearrangement of 4-tert-nonyl-phenyl acetate, prepared from a commercially available 4-tert-nonylphenol. The latter compound had been obtained by alkylation of phenol with a mixture of branched propene trimers. Table II shows the percentage of the copper extracted at various moments after the start of the experiment, under the heading experiment 1.

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B) According to the invent-ion The kerosine contained 0.2 mol of methyl 2-hydroxy-5-tert-nonylphenyl ketone oxime per litre and a second oxime numbered as stated in Table Il, second line.
The third line of Table II gives the concentrations, calculated on methyl 2-hydroxy-5-tert-nonylphenyl ketone oxime - in which the second oxime was present.
Table II also presents the percentage of copper extracted under the headings experiments 2 to 17. These results show - compared with those of experiment 1 - a considerable synergistic effect on the extraction rate.
C. Not according to the invention ____________ _________________ The kerosine used in experiment No. 18 contained 0.2 mol of 2-hydroxy-5-tert-nonylbenzophenone oxime per litre and 11% of 5,8-diethyl-7-hydroxy-6-dodeca-none oxime, calculated on the former oxime. Table I, first column from the right, shows the results.
The extraction rates achieved with oximes 1 and 2 are higher than, and those achieved with oximes 3,4,7 and 8 about equal to, that obtained with the known mixture of oximes used in experiment 18.
Example II
A. Not according to the invention The kerosine only contained 0.2 m of benzyl 2-hydroxy-5-tert-nonylphenyl ketone oxime per litre, Table III
shows the percentage of copper extracted under the heading experiment No 1.

~083~328 B. Accordin~ to the nvention l'he kerosine contained 0.2 rno:L c,r benzyl 2 hydroxy-5-tert-nonyLpheny1 ketone oxime per litre and 10 %m, calculated on benzyl 2-hydroxy-5-tert-nonyl phenyl ketone oxime, of a second oxime, the number of which is stated in Table III, second line. Table III presents the percentage of copper extracted under the headings experiments 2-5.
Table III

Sample taken Experiment No, 11) 2 3 4 5 ... seconds Second oxime, No. none 1 3 8 9 after start of experiment _____ ____________________________ ____ ___ ____ ____ _____ -% copper extracted ` . 120 88 100 100 __~.________________________________________________________ 1) not according to the invention 10The results of experiments 2-5 show - compared with those of experiment 1 - a considerable synergistic :~ effect on the extraction rate. The extraction rates achieved with oximes 1 and 3 are higher than, and those achieved with oximes 8 and 9 about equal to~
. 15 those obtained with the known mixture of two oximes in experiment 18 of Example 1.

Example III

A. Not according to the invention The kerosine only contained 0.2 mol of 2-hydroxy-5-(1-methyloctyl)benzophhenone oxime per litre. Table IV shows the percentage of copper extracted under the heading experiment No. 1.

~ Table IV

: Sample taken Experiment No. ll) 2 3 4... seconds Second oxime, No. none 1 3 8 after start of experiment _____ ______________________________ ______ _____ _____ _____ ~ % copper extracted ____________________________________ ______ _____ _____ _____ : 15 51 97 95 96 . 81 100 100 100 : 120 96 _____________ 1) not according to the invention B. According to the invention The kerosine contained 0.2 mol of 2-hydroxy-5-(1-methyloctyl)benzophenone oxi~e per litre and 10 %m, calculated on 2-hydroxy-5-(1-methyloctyl)benzophenone oxime, of a second oxime, the number of which is stated in Table IV, second line. Table IV presents the percentage Or copper extracted under the headings experiments 2-4. The results of experiments 2,3 and 4 show -compa.red with those of experiment 1 - a considerable ; .

10838:Z8 synergistic effect on theextraction rate. The extraction rates are higher than those obtained with the known mixture of oximes in experlment ~8 of Example I.
Example IV
A. Not according to the invention ____________ _________________ The kerosine only contained 0.2 mol of 2-hydroxy-3,5-di(1-methylbutyl)benzaldoxime per litre. Table V
shows the percentage of copper extracted under the heading experiment No. 1;
Table V

Sample taken Experiment No. 1 2 3 4 ... seconds Second oxime, No. none 1 3 8 after start of experiment _____ _____________________________ _____ _____ ____ _______ % copper extracted ___________________________________ _____ _____ ____ _______ _ _ _ _ _ _ _ B. According to the invention The kerosine contained 0.2 mol of 2-hydroxy-3,5-ai (1-methylbutyl)benzaldoxime per litre and 10 %m, calculated on 2-hydroxy-3,5-di(1-methylbutyl)benzaldoxime, of ;
a second oxime, the number of which is stated in Table V, second line. Table V presents the percentage of copper extracted under the headings experiments 2-4.
The results of experiments 2,3 and 4 show - compared .

. . . :
: ., . ~ ' ' ' '' ' ' , .

with those of experiment 1 - a considerable synergistic effect on the extraction rate. The extraction rate achieved with oxime 1 is higher than that J and the rates achieved with oximes 3 and 8 are about equal to those, obtained with the known mixture of oximes in experiment 18 of Example I.
Example V
A solution of 0.5 mol of 2-methylcyclododecene in 150 ml of n-heptane was added dropwise at a temperature 0C to a solution of 0.4 mol of nitrosyl sulphuric acid in 140 g cf a mixture of 75 %w suphuric acid and 25 %w of water. The reaction mixture was vigorously stirred during the addition until the reaction was complete. The phases were allowed to separate, the organic layer was removed and the aqueous layer washed three times with an equal volume of n-heptane. The washed aqueous solution was diluted to 500 ml with water, after which a 28 %w aqueous ammonia solution was added until the pH had reached a value of 7.5.
The resulting solution was extracted with an equal volume of diethyl ether, the extract phase obtained dried over anhydrous sodium sulphate and the dried - phase boiled down at a pressure of 15 mm Hg to give 2-hydroxy-2-methylcyclododecanone oxime in a yield of 90%, calculated on 2-methylcyclododecene converted.
- The structure was confirmed by proton magnetic resonance ~, and mass spectrum analysis.
. ' ~' ~083828 Example VI
The experiment described in Example IV was repeated with 2,6,10-trimethyl~1-cyclododecene - prepared by trimerization of isprene followed by partial hydrogenation Or the 1,5,9-trimethyl-1,5,9-cyclododecatriene formed - instead of 2-methylcyclododecene. The yield of 2-hydroxy-2,6,10-trimethylcyclododecanone oxime was 91%, calculated on olefin converted. The structure was confirmed by proton magnetic resonance and mass spectrum analysis.
Example VII
The experiment described in Example IV was repeated with 4-pentyl-1-cyclohexene instead of 2-methylcyclododecene.
The yield of 2-hydroxy-4-pentylcyclohexanone oxime was 84%, calculated on 4-pentyl-1-cyclohexene converted.
The structure was confirmed by proton magnetic resonance and ma s spectrum Analysie~.

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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERrY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for the separation of copper values from an acidic aqueous solution thereof by liquid-liquid extraction with an extractant comprising an organic solvent, and dissolved therein (1) a hydroxyoxime of the general formula A - C(=NOH) - R (I) in which R represents a hydrogen atom or an aliphatic group and A an aromatic group carrying as substituents a hydroxyl group at a ring carbon atom in a 2-position, the number 1 being assigned to the ring carbon atom to which the -C(=NOH)-R group is attached, and optionally at least one organic group D
and/or (2) a 2-hydroxybenzophenone oxime substituted by a saturated or ethylenically unsaturated aliphatic group or groups or the corresponding ether group or groups, in combination with a dissolved (a) hydrocarbyl hydroxymethyl ketone oxime, (b) 2-hydroxyaldoxime in which the carbon atom carrying the hydroxyl group also carries two hydrocarbyl groups or one hydrocarbyl group and one hydrogen atom, (c) 2-hydroxycycloalkanone oxime in which the cycloaliphatic ring also carries at least one organic group, or (d) aliphatic alpha-hydroxy-oxime of the general formula (II) in which R1, R2 and R3 each represent an organic group and R3 may also represent a hydrogen atom with the proviso that an aliphatic alpha-hydroxy-oxime of the general formula II is present only wherever a hydroxyoxime of the general formula I is also present.

2. A process as claimed in claim 1, in which the oximes of sub (a) (b), (c) or (d) are present in the extractant in an amount of 1-100 mol %
based on the oximes of sub (1) and/or (2).

3. A process as claimed in claim 2, in which the oximes of sub (a), (b), (c) or (d) are present in the extractant in an amount of 4-12 mol %
based on the oximes of sub (1) and/or (2).

4. A process as claimed in claim 1, in which the hydrocarbyl hydroxy-methyl ketone oxime of sub (a) is an alkyl hydroxymethyl ketone oxime.

5. A process as claimed in claim 4, in which the alkyl group has more than five carbon atoms.

6. A process as claimed in claim 4, in which the alkyl hydroxymethyl ketone oxime is n-dodecyl hydroxymethyl ketone oxime.

7. A process as claimed in claim 1, in which the hydrocarbyl hydroxymethyl ketone oxime of sub (a) is an alkylphenyl hydroxymethyl ketone oxime.

8. A process as claimed in claim 7, in which the alkylphenyl hydroxy-methyl ketone oxime is p-n-decylphenyl hydroxymethyl ketone oxime.

9. A process as claimed in claim 1 in which the 2-hydroxyaldoxime of sub (b) is a 2-hydroxyalkanal oxime.

10. A process as claimed in claim 9 in which the 2-hydroxyalkanal oxime has from eight to 20 carbon atoms per molecule.

11. A process as claimed in claim 9 in which the 2-hydroxyalkanal oxime is 2-hydroxy-2-methylpentadecanal oxime.

12. A process as claimed in claim 9 in which the 2-hydroxyalkanal oxime is 2-hexyl-2-hydroxydecanal oxime.

13. A process as claimed in claim 9 in which the 2-hydroxyalkanal oxime is 2-hydroxy-2-pentylnonanal oxime.

14. A process as claimed in claim 1 in which the at least one organic group attached to the cycloaliphatic ring of the 2-hydroxycycloalkanone oxime of sub (c) is an alkyl group.

15. A process as claimed in claim 14 in which the 2-hydroxycycloalkanone oxime is 2-hydroxycyclododecanone oxime.

16. A process as claimed in claim 15 in which the 2-hydroxycyclodode-canone oxime is 2-hydroxy-2-alkylcyclododecanone oxime.

17. A process as claimed in claim 16 in which the 2-hydroxy-2-alkyl-cyclododecanone oxime is 2-hydroxy-2-methyl-cyclododecanone oxime.

18. A process as claimed in claim 16, in which the 2-hydroxy-2-alkyl-cyclododecanone oxime is 2-hydroxy-2,6,10-trimethylcyclododecanone oxime.

19. A process as claimed in claim 1 in which R1 and R2 in formula II
are the same and are secondary alkyl groups.

20. A process as claimed in claim 19 in which the alpha-hydroxy-oxime of the general formula II is 5,8-diethyl-7-hydroxy-6-dodecanone oxime.

21. A process as claimed in claim 1 in which A in the general formula I carries one or more alkyl groups as said at least one organic group D.

22. A process as claimed in claim 21 in which the hydroxy-oxime of the general formula I contains at least seven carbon atoms in the alkyl groups D.

23. A process as claimed in claim 1 in which R in the general formula I represents an alkyl group.

24. A process as claimed in claim 23 in which R represents a methyl group.

25. A process as claimed in claim 24, in which the compound of the general formula I is methyl 2-hydroxy-5-tertnonylphenyl ketone oxime.

26. A process as claimed in claim 1 in which R in the general formula I represents a benzyl group.

27. A process as claimed in claim 26 in which the compound of the general formula I is benzyl 2-hydroxy-5-tert-nonylphenyl ketone oxime.

28. A process as claimed in claim 1 in which the compound of the general formula I is 2-hydroxy-3,5-di(1-methylbutyl)benzaldoxime.

29. A process as claimed in claim 1 in which the 2-hydroxybenzophenone oxime carries an alkyl substituent in one 5-position.

30. A process as claimed in claim 29 in which the 2-hydroxybenzophenone oxime used is 2-hydroxy-5-tert-nonylbenzophenone oxime.

31. A process as claimed in claim 1 in which the aqueous solution has a pH between 0 and 3 and contains iron values.

32. A liquid extractant for use in a process for the separation of copper values from acidic aqueous solutions as claimed in claim 1.