Ketoximes, processes therefor, and copper extraction process

Details Ketoximes, processes therefor, and copper extraction process Ketoximes, processes therefor, and copper extraction process

1999-02-25

2002-01-29

O'Sullivan, Peter (Department: 1621)

Organic compounds -- part of the class 532-570 series

Organic compounds

Amino nitrogen containing

C564S265000, C564S266000, C568S333000, C568S337000

Reexamination Certificate

active

06342635

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to processes for the extraction of copper from copper ores, and to compounds useful in such processes.
BACKGROUND OF THE INVENTION
In the extraction of copper from copper ores, various reagents have been used for the extraction, including ketoximes, aldoximes, mixtures of ketoximes and aldoximes, and certain alcohols and esters.
SUMMARY OF THE INVENTION
The present invention relates to an improved process for the preparation of ketoximes, to the ketoximes prepared by the process, to mixtures comprising the ketoximes and aldoximes, and to a process for extracting copper metal from copper ores using the mixtures of ketoximes and aldoximes.
DETAILED DESCRIPTION OF THE INVENTION
Other than in the operating examples, or where otherwise indicated, all numbers expressing quantities of ingredients or reaction conditions used herein are to be understood as modified in all instances by the term “about”.
One embodiment of the improved process of the invention for the preparation of ketoximes comprises the following steps:
A) heating at least one phenol ester containing unreacted phenols in an inert organic solvent with a Lewis acid and a monocarboxylic acid halide (preferably chlorine or bromine) or anhydride to obtain a ketone by the Fries Rearrangement;
B) isolating the ketone reaction product from the reaction mixture; and
C) reacting hydroxylamine or a salt thereof with the ketone obtained in step B) to produce a ketoxime from said ketone.
While the above process will work with various phenol esters, it is preferred that in step A) the at least one phenol ester has the formula I or II below:
in which R is an alkyl group having from 1 to 25 carbon atoms, an ethylenically unsaturated aliphatic group containing from 3 to 25 carbon atoms, or —OR
1
where R
1
is an alkyl group or ethylenically unsaturated aliphatic group as defined above, and R
2
is an alkyl group containing 1 to 25 carbon atoms or an ethylenically unsaturated aliphatic group containing 3 to 25 carbon atoms; with the proviso that the total number of carbon atoms in the R and R
2
groups is from 3 to 25.
in which R has the same meaning as in formula I; n is 0 or 1; and R
3
is an alkyl group having from 1 to 25 carbon atoms, an ethylenically unsaturated aliphatic group containing from 3 to 25 carbon atoms, or —OR
1
wherein R
1
is an alkyl group or ethylenically unsaturated aliphatic group as defined above, with the proviso that the total number of carbon atoms in the R and R
3
groups is from 3 to 25.
The above phenol esters can be readily obtained from the corresponding phenols by methods well known to the art.
The organic solvent is any organic solvent or mixture of solvents which is immiscible with water and inert to the water, to the Lewis acid catalyst, and to the monocarboxylic acid halide or anhydride, e.g. aliphatic and aromatic hydrocarbons, chlorinated hydrocarbons, esters and ethers. Toluene is preferred.
The Lewis acid is preferably aluminum chloride, although other Lewis acids can also be used, such as boron trifluoride. The quantity of Lewis acid can range from 0.9 to 1.5 moles per mole of phenol ester.
While various monocarboxylic acid halides and anhydrides can be used in the present process, the monocarboxylic acid halide or anhydride is preferably selected from compounds of formula III or IV below:
where R
2
is an alkyl group containing 1 to 25 carbon atoms or an ethylenically unsaturated aliphatic group containing 3 to 25 carbon atoms, with the proviso that the total number of carbon atoms in the R group in formula I plus the R
2
group in formula III is from 3 to 25; and x is halogen or
where R
3
is an alkyl group having from 1 to 25 carbon atoms, an ethylenically unsaturated aliphatic group containing from 3 to 25 carbon atoms, or —OR
1
where R
1
is an alkyl group or ethylenically unsaturated aliphatic group as defined above; n is 0 or 1; and y is halogen or
with the proviso that the total number of carbon atoms in the R group in formula II plus the R
3
group in formula IV is from 3 to 25.
The R
2
or R
3
groups in the monocarboxylic acid halide or anhydride can be the same as the R
2
or R
3
groups in the esters of formulae I and II, or can be different therefrom, but are preferably the same.
The reaction temperature in step A) can range from 50° to 150° C., preferably from 100 to 125° C., and more preferably at the reflux temperature of the mixture.
The mixture is preferably heated for a time period in the range of from 2 to 6 hours.
It is also preferred to add the Lewis acid and monocarboxylic acid halide or anhydride by slow addition during the entire reaction period or during at least a major portion thereof.
It is also preferred to maintain the reaction mixture at the reaction temperature for an additional period (holding period) of from 1 to 4 hours.
For every mole of phenol ester, from 0.5 to 2 moles, preferably from 0.9 to 1.1 moles of Lewis acid is present, and from 0.1 to 1 mole, preferably from 0.2 to 0.6 moles of monocarboxylic acid halide or anhydride is present. The above ranges are however not critical and quantities of components outside these ranges can be employed.
Step B) can be carried out in any convenient manner such as by washing the reaction mixture with water to remove the Lewis acid, and then distilling off the inert organic solvent, followed by distillation to obtain a substantially pure ketone.
Step C) is carried out by heating the mixture to a temperature between 20° and 90° C. until the reaction is substantially complete.
The hydroxylamine or salt thereof is added in approximately molar proportions based on the quantity of ketone reaction product isolated in step B).
Hydroxylamine itself or a salt thereof, such as the sulfate salt, can be used in step C).
The reaction in step C) is preferably carried out in a solvent such as aqueous ethanol or toulene. When a salt of hydroxylamine is used, a base such as sodium carbonate or sodium or potassium hydroxide is added in a quantity sufficient to liberate hydroxylamine.
When the reaction is completed, usually after a few hours, the reaction mixture is neutralized if needed with a mineral acid, and the ketoxime product extracted with a water-immiscible solvent, e.g. chloroform toluene, or kerosene, or if a solid, collected by filtration.
A second embodiment of the improved process of the invention for the preparation of ketoximes comprises the following steps:
A) reacting a phenol with a monocarboxylic acid, acid halide, or acid anhydride in an inert organic solvent in the presence of an acid catalyst to esterify the phenol;
B) removing any water of reaction either during step A or in a separate step following step A);
C) adding a Lewis acid to the resulting anhydrous reaction mixture;
D) reacting the reaction mixture from step C) to a reaction temperature and for a time to convert most of the esterified phenol to a ketone by the Fries Rearrangement;
E) maintaining the reaction for an additional time period of from 2 to 10 hours at the reaction temperature;
F) at a time of from half to three-quarters of said additional time period adding to the heated reaction mixture additional aliphatic monocarboxylic acid, acid halide or acid anhydride, optionally with additional Lewis acid, and continuing to maintain the heated reaction mixture at the reaction temperature for the remainder of said additional time period;
G) isolating the ketone reaction product from the reaction mixture; and
H) reacting hydroxylamine or a salt thereof with the ketone obtained in step G) to produce a ketoxime from said ketone.
In step A) the phenol has the formula:
where R is an alkyl group having from 1 to 25 carbon atoms, an ethylenically unsaturated aliphatic group containing from 3 to 25 carbon atoms, or an —OR
1
group where R
1
is an alkyl group or ethylenically unsaturated aliphatic group as defined above.
The monocarboxylic acid, acid halide, or acid anhydride is selected from a compound of formula VI or formula VII below:
where R
2
is an alkyl group containing 1 to 25 carbon atoms or an

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