ETHERAMINE COMPOUNDS AND THEIR USE AS FLOTATION COLLECTORS

Abstract

The present invention relates to a compound of formula (I): in which: - the R1 and R2 groups, which may be identical or different, are, independently of one another, a saturated or unsaturated, linear, branched or cyclic hydrocarbon group comprising from 1 to 15 carbon atoms, preferably from 1 to 10 carbon atoms; - the R3 and R4 groups, which may be identical or different, are chosen, independently of one another, from a hydrogen atom, the methyl group and the ethyl group; - the R, R6 and R7 groups, which may be identical or different, are chosen, independently of one another, from a hydrogen atom and an alkyl group comprising from 1 to 6 carbon atoms, preferably from 1 to 4 carbon atoms, more preferably from 1 to 3 carbon atoms; - n is an integer of 0 to 20; and - m is an integer of 1 to 6.

Description

ETHERAMINE COMPOUNDS AND THEIR USE AS FLOTATION COLLECTOR

[0001] The present invention relates to the general field of etheramines. The etheramine family represents a unique group of chemicals offering a wide range of properties. Indeed, they can be used, in particular, as lubricants, cationic surfactants, flotation collectors for ores, or as corrosion inhibitors. Thus, they constitute a class of materials of major industrial interest to many players. The etheramine market has, moreover, been well-developed for several decades.

[0002] Etheramines are classically synthesized by first reacting an alcohol with a nitrile compound, usually acrylonitrile, in the presence of a basic catalyst. A hydrogenation step of the resulting product is then carried out to isolate the target etheramine.

[0003] Thus, US patent 5196589 describes a process for manufacturing an etheramine by first reacting an alcohol with acrylonitrile in the presence of an alkali catalyst. A hydrogenation step is then carried out to obtain the desired etheramine. The distinctive feature of this process lies in the fact that the alcohol, a compound comprising 6 to 36 carbon atoms, is in the presence of a stable free radical compound, thereby significantly reducing the formation of unwanted byproducts.

[0004] Patent EP1219597 discloses a process for preparing an etheramine comprising a first step of reacting a primary or secondary alcohol with acrylonitrile in the presence of an alkali metal hydroxide, followed by a second step of hydrogenating the resulting product. The primary or secondary alcohol is a compound comprising 6 to 24 carbon atoms.

[0005] On the other hand, at a time when the environmental issue is truly important, none of these documents indicates the use of any bio-based or biodegradable reagent with a good ecotoxicological profile.

[0006] In addition, it is known that particular etheramines, in particular the commercially available products Tomamine® PA-14 and Tomamine® DA-14, are used for the selective removal of silicates during the flotation of ores.

[0007] It would therefore be advantageous to provide an etheramine obtained from at least one bio-based and biodegradable reagent. It would also be beneficial if the use of such an etheramine led to more selective removal of silicates during ore flotation than commercial etheramines.

[0008] The present invention relates to a compound of formula (I): (I) in which: the groups Ri and R2, identical or different, represent, independently of each other, a hydrocarbon group, linear, branched or cyclic, saturated or unsaturated, comprising from 1 to 15 carbon atoms, preferably from 1 to 10 carbon atoms; the groups R3 and R4, identical or different, are chosen, independently of each other, from among the hydrogen atom, the methyl group and the ethyl group; the groups R5, R6, and R7, identical or different, are chosen, independently of each other, from the hydrogen atom and an alkyl group comprising from 1 to 6 carbon atoms, preferably from 1 to 4 carbon atoms, preferably still from 1 to 3 carbon atoms; n is an integer ranging from 0 to 20; m is an integer ranging from 1 to 6.

[0009] According to a preferred embodiment, when Ri is a hexyl group, R2 is a methyl group, n is equal to 0, R5, R6 and R7 denote a hydrogen atom, then m is different from 1.

[0010] According to another preferred embodiment, the total number of carbon atoms of the Ri and R2 groups is between 5 and 20 carbon atoms, preferably between 6 and 20 carbon atoms.

[0011] The present invention also relates to a method for manufacturing the compound of formula (I) according to the invention.

[0012] Another object of the invention is a compound of formula (V): in which: the groups Ri, R2, R3, R4, R5, R6 and R7 are as defined previously, and n is as defined previously.

[0013] The present invention also relates to a compound of formula (VI): in which: the groups Ri, R2, R3, R4, R5, R6 and R7 are as defined previously, and n and m are as defined previously.

[0014] Another object of the present invention relates to the use of the compound according to the invention as, in particular, a flotation collector for ores.

[0015] Other advantages and features of the invention will become more apparent upon examination of the detailed description.

[0016] It is further specified that the expressions "between ... and ..." and "from ... to ..." used in this description should be understood as including each of the limits mentioned.

[0017] The compound according to the invention has the formula (I) mentioned above.

[0018] Preferably, n is an integer from 0 to 10, more preferably from 0 to 5, even more preferably from 0 to 1.

[0019] Advantageously, the R3 and R4 groups, identical or different, are chosen, independently of each other, from the hydrogen atom and the methyl group.

[0020] Preferably, m is an integer from 1 to 4, more preferably m is equal to 1, 2 or 3.

[0021] The invention also relates to a method for manufacturing the compound of formula (I) according to the invention, comprising successively: a reaction step of a compound of formula (II): (II) in which the groups Ri, R2, R3 and R4 and n are as defined previously; with an α,β-unsaturated nitrile; a hydrogenation reaction; the product from these steps being likely to react in series (m-1) times with α,β-unsaturated nitrile, then with dihydrogen, m being as defined previously.

[0022] According to a preferred embodiment, the α,β-unsaturated nitrile is chosen from acrylonitrile and methacrylonitrile, preferably acrylonitrile.

[0023] Thus, when n equals 0, the compound of formula (II) can be 2-octanol. This alcohol is of particular interest for several reasons. Indeed, it is a bio-based product, biodegradable, and has a good ecotoxicological profile. Furthermore, the boiling point of 2-octanol is high and its production cost is quite reasonable.

[0024] Advantageously, the molar ratio of α,β-unsaturated nitrile to the compound of formula (II) varies from 0.8 to 1.2, preferably from 0.9 to 1.2.

[0025] Particularly advantageously, the molar ratio of α,β-unsaturated nitrile to the compound of formula (II) varies from 1.01 to 1.1, that is to say that the reaction of the compound of formula (II) with α,β-unsaturated nitrile is carried out with a slight excess of α,β-unsaturated nitrile.

[0026] Preferably, the reaction of the compound of formula (II) with the α,β-unsaturated nitrile is carried out in the presence of at least one basic catalyst CB.

[0027] Preferably, the basic catalyst CB is chosen from alkali and alkaline earth hydroxides, alkali alcoholates, alkali hydrides, basic resins and quaternary ammonium hydroxides.

[0028] In a particularly preferred manner, the basic catalyst CB is chosen from sodium hydroxide, potassium hydroxide, sodium hydride and potassium hydride.

[0029] According to a particular embodiment of the invention, the quantity of basic catalyst CB used varies from 0.1% to 2% by weight, preferably from 0.5% to 1% by weight, relative to the total weight of the compound of formula (II).

[0030] The reaction temperature of the compound of formula (II) with α,β-unsaturated nitrile can vary widely. Preferably, it varies from 20 to 75°C, more preferably from 25 to 70°C, and even more preferably from 25 to 65°C.

[0031] Advantageously, the reaction of the compound of formula (II) with α,β-unsaturated nitrile is carried out without a solvent, but it is also possible to use a solvent that is neutral with respect to the reaction of the compound of formula (II) with α,β-unsaturated nitrile.

[0032] A "reaction-neutral solvent" is understood to mean any solvent that does not chemically interact with the reactants of the reaction of the compound of formula (II) with α,β-unsaturated nitrile.

[0033] Preferably, neutral solvents with respect to the reaction are chosen from ethers, dimethylformamide and aromatic solvents solubilizing reagents chosen from toluene and xylenes.

[0034] Where appropriate, the basic catalyst CB can be neutralized at the end of the reaction by any means known to those skilled in the art, such as, for example, and without limitation, an organic or mineral acid, preferably chosen from hydrochloric acid and acetic acid or, alternatively, the catalyst can be removed, for example by filtration when it is of a solid nature.

[0035] Preferably, the hydrogenation reaction is carried out in the presence of at least one CT catalyst.

[0036] According to a particular embodiment, said CT catalyst is selected from Raney nickel and Raney cobalt.

[0037] Advantageously, the amount of CT catalyst varies from 0.5 to 10% by weight, preferably from 2 to 8% by weight, relative to the weight of the product from the reaction of the compound of formula (II) with the α,β-unsaturated nitrile.

[0038] Preferably, the pressure during the hydrogenation reaction varies from 1 to 10 MPa, preferably from 1.5 to 5 MPa.

[0039] Preferably, the temperature of the hydrogenation reaction varies from 50 to 170°C, preferably from 70 to 150°C.

[0040] According to a particular embodiment of the invention, in order to promote the formation of the primary amine, it is possible to add a quantity of ammonia capable of generating a partial pressure of ammonia. Advantageously, an ammonia / nitrile molar ratio varying from 0.5 to 2 is suitable. Alternatively, 11 It is also possible to add a strong base, preferably chosen from sodium hydroxide and potassium hydroxide, in an amount that can vary from 100 ppm to 5000 ppm, preferably from 500 to 5000 ppm, more preferably from 500 to 2500 ppm, relative to the amount of product from the reaction of the compound of formula (II) with the α,β-unsaturated nitrile.

[0041] Particularly advantageously, the addition of said quantity of ammonia capable of generating a partial pressure of ammonia and the addition of said strong base are combined.

[0042] Preferably, the successive steps of reacting the compound of formula (II) with the α,β-unsaturated nitrile and of the hydrogenation reaction are carried out in the same reactor.

[0043] It is also possible to work in a solvent medium with organic or hydro-organic solvents, such as, for example, alcohols (methanol, ethanol, isopropanol) and any other solvent used for hydrogenation reactions and solubilizing the reactants and the final products.

[0044] Batch processing is possible by introducing all the reactants and carrying out the hydrogenation reaction. Semi-batch processing is also possible by loading the solvent, ammonia and / or strong base, catalyst and hydrogen, then continuously introducing the condensation product resulting from the reaction of the compound of formula (II) with the α,β-unsaturated nitrile.

[0045] Advantageously, the reaction of the compound of formula (II) with α,β-unsaturated nitrile and the hydrogenation reaction are carried out in different reactors.

[0046] Preferably, the process according to the invention comprises, prior to the successive steps of reaction of the compound of formula (II) with an α,β-unsaturated nitrile and hydrogenation, a step of reaction of an alcohol of formula (III): where Ri and R2 are as defined previously, with n composed of formula(s) in which: Groups R3 and R4 are as defined previously, and n is such as defined previously.

[0047] The invention also relates to the use of a compound of formula (I) as defined above, as a lubricant, cationic surfactant, flotation collector for ores, corrosion inhibitor, fuel additive and crosslinking agent for epoxy resins.

[0048] The use of the compound of formula (I), as a flotation collector for ores is particularly preferred.

[0049] The invention is illustrated by the following examples, which are in no way limiting. EXAMPLES

[0050] The 2-octanol used is the Refined grade product marketed by Arkema. Example 1: Synthesis of 3-(2-octyloxy)-propanamine 1) Synthesis of 3-(2-octyloxy)-propionitrile a) Use of potassium hydroxide

[0051] In a reactor equipped with a stirrer and fitted with a dropping funnel, a condenser, a nitrogen inerting system, and a double jacket for heating, 130 g (1 M) of 2-octanol and 2 g of potassium hydroxide, in a 50% aqueous solution, are loaded. The reaction mixture is heated to 45°C under stirring and in an inert atmosphere, and then 55 g (1.04 M) of acrylonitrile are added dropwise. The temperature is maintained after dropping until the reaction is complete. At the end of the reaction, the basic catalyst is neutralized by stoichiometry with hydrochloric acid. Propionitrile ether is isolated by thin-film distillation with a molar yield of 90%. b) Use of sodium hydride

[0052] In a reactor equipped with a stirrer and fitted with a dropping funnel, a condenser, a nitrogen inerting system, and a double jacket for heating, 130 g (1 M) of 2-octanol and 0.6 g of sodium hydride are loaded. The reactor is purged with nitrogen to remove the hydrogen formed. The reaction mixture is heated to 35°C under stirring and in an inert atmosphere, and then 55 g (1.04 M) of acrylonitrile are added dropwise. The temperature is maintained after dropping until the reaction is complete. At the end of the reaction, the basic catalyst is neutralized by stoichiometry with hydrochloric acid. Propionitrile ether is isolated by thin-film distillation with a molar yield of 91%. 2) Hydrogenation of 3-(2-octyloxy)-propionitrile

[0053] In a 300 cm³ Autoclave, of the Engineer type, equipped with a self-aspirating turbine-type stirring system, a cooling coil, and a pressure and temperature control system, 183 g (1 M) of 3-(2-octyloxy)-propionitrile obtained according to processes 1)a) or 1)b), 14 g of Raney nickel, and 2000 ppm of KOH, in a 50% aqueous solution, are loaded. The autoclave is locked and purged with nitrogen. Then, hydrogen is introduced during the temperature ramp-up so that a total pressure of 3 MPa at 110°C is obtained. The reaction is continued until no more hydrogen is consumed. At the end of the reaction, the catalyst is recovered by filtration. The crude reaction mixture is thin-film distilled to obtain 3-(2-octyloxy)-propanamine with a molar yield of 85%. Example 2: Synthesis of an etherdiamine 1) Synthesis of 3-[3-(2-octyloxy)propylaminel-propionitrile

[0054] In a reactor equipped with a stirrer and fitted with a dropping funnel, a condenser, a nitrogen inerting system and a double jacket for heating, 225 g (1.2 M) of 3-(2-octyloxy)-propanamine and 2.25 g of water are loaded.

[0055] The reaction mixture is heated to 60°C under stirring and in an inert atmosphere, then 65 g (1.226 M) of acrylonitrile is added dropwise. The temperature is maintained after adding the acrylonitrile until the reaction is complete, approximately 2 hours. 3-[3-(2-octyloxy)propylamine]-propionitrile is obtained with a molar yield of 87%. 2) Hydrogenation of 3-[3-(2-octyloxy)propylaminel-propionitrile

[0056] In a 500 cm³ Autoclave Engineer, equipped with a self-aspirating turbine-type stirring system, a cooling coil, and a pressure and temperature control system, 200 g (1 M) of 3-[3-(2-octyloxy)propylamine]-propionitrile obtained according to the above process and 3.6 g of Raney Nickel are loaded. The autoclave is locked and purged with nitrogen. The reaction mixture is then heated to 75°C. Ammonia is introduced until a total pressure of 0.8 MPa is reached. Hydrogen is then introduced during the temperature rise so that a total pressure of 3 MPa is obtained at 120°C. The reaction is continued until no more hydrogen is consumed. At the end of the reaction, the autoclave is degassed and the catalyst is recovered by filtration. Crude etherdiamine is obtained with a molar yield of 83%. Example 3: Synthesis of a polyetheramine 1) Synthesis of a propionitrile tris(ether)

[0057] In a reactor equipped with a stirrer and fitted with a dropping funnel, a condenser, a nitrogen inerting system, and a double jacket for heating, 262 g (1 M) of tris(ethoxylated) 2-octanol and 2 g of potassium hydroxide, in a 50% aqueous solution, are loaded. The reaction mixture is heated to 55°C under stirring and in an inert atmosphere, and then 55.6 g (1.05 M) of acrylonitrile is added dropwise. The temperature is maintained after dropping until the reaction is complete. At the end of the reaction, the basic catalyst is neutralized by stoichiometry with hydrochloric acid. Tris(ether)propionitrile is obtained with a molar yield of 89%. 2) Hydrogenation of tris(ether)propionitrile

[0058] In a 500 cm³ Autoclave Engineer, equipped with a self-aspirating turbine-type stirring system, a cooling coil, and a pressure and temperature control system, 252 g (0.8 M) of tris(ether)propionitrile, obtained according to the above process, 20 g of Raney nickel, and 2000 ppm of potassium hydroxide, in a 50% aqueous solution, are loaded. The autoclave is locked and purged with nitrogen. Then, hydrogen is introduced during the temperature ramp-up so that a total pressure of 3 MPa at 120°C is obtained. The reaction is continued until no more hydrogen is consumed. At the end of the reaction, the autoclave is degassed, and the catalyst is recovered by filtration. Tris(ether)amine is obtained with a molar yield of 81%. Example 4: Use of the compound according to the invention as a flotation collector

[0059] A phosphate ore containing silicates is purified by reverse flotation. The tests are carried out in an Outotec flotation cell.

[0060] Initially, 2.5 liters of tap water and 340 g of crushed phosphate ore (with a particle size ranging from 30 to 300 µm) are introduced. The turbine speed is adjusted to 1500 rpm to ensure that the ore is suspended throughout the cell volume. 0.34 g of phosphoric acid, in an 85% aqueous solution, is then added, and agitation is maintained for three minutes.

[0061] Then, 0.17 g of a carbonate collector supplied by CECA under the trade name Melioran® P312 is added and agitation is maintained for two minutes. Air is then supplied to the cell at a flow rate of 3 L / min and flotation is carried out for two minutes. Regular collection of the foams is performed with a spatula.

[0062] The air supply is switched off at the end of flotation and 10.2 g of cationic collector for silicates is added. Agitation is maintained for two minutes before the air supply is restored. Flotation is carried out for four minutes.

[0063] Following these two steps, the ore remaining in the flotation cell is filtered using a Buchner funnel and dried in an oven overnight. The dried ore is then weighed to determine the quantity recovered and sent for analysis to determine its composition.

[0064] The comparative tests are based on five cation collectors for silicates used in the second flotation step.

[0065] The starting ore is of the fluoroapatite type containing 43% by weight of calcite and 17% by weight of quartz, relative to the total weight of the ore, as impurities. The P2O5 compound content is 13.8% by weight relative to the weight of the ore.

[0066] Compound A is a comparative compound. It is Noramac® C26 (N-alkyl coco-amino acetate) marketed by the company CECA.

[0067] Compound B is a comparator compound. It is Tomamine® PA-14 (isodecyloxypropylamine) marketed by Air Products.

[0068] Compound C is a comparative compound. It is Tomamine® DA-14 (isodecyloxypropyl-1,3-diaminopropane) marketed by Air Products.

[0069] Compound D is a compound according to the invention corresponding to the following formula (VII):

[0070] Compound E is a compound according to the invention corresponding to the following formula (VIII):

[0071] The results of the ore analysis after flotation are summarized in Table 1 below: -- Table 1 --

[0072] Table 1 clearly shows that compounds D and E according to the invention allow for the removal of a greater quantity of silicates than the three comparative compounds A, B and C.

[0073] Furthermore, the final P2O5 content is greater with the use of compounds D and E than that associated with the use of the comparative compounds.

[0074] Thus, it has been demonstrated that the use of the compound according to the invention leads to selective removal during the flotation of a phosphate ore. This property is even improved compared to commercial products.

Claims

DEMANDS 1. Compound of formula (I): in which: the groups Ri and F¾, identical or different, represent, independently of each other, a hydrocarbon group, linear, branched or cyclic, saturated or unsaturated, comprising from 1 to 15 carbon atoms, preferably from 1 to 10 carbon atoms; the groups R3 and R4, identical or different, are chosen, independently of each other, from among the hydrogen atom, the methyl group and the ethyl group; the groups R5, R6 and R7, identical or different, are chosen, independently of each other, from the hydrogen atom and an alkyl group comprising from 1 to 6 carbon atoms, preferably from 1 to 4 carbon atoms, preferably still from 1 to 3 carbon atoms; n is an integer ranging from 0 to 20; m is an integer ranging from 1 to 6.

2. Compound according to claim 1, characterized in that n is an integer from 0 to 10, more preferably from 0 to 5, even more preferably from 0 to 1.

3. Compound according to claim 1 or claim 2, characterized in that the groups R3 and R4, identical or different, are chosen, independently of each other, from the hydrogen atom and the methyl group.

4. Compound according to any one of claims 1 to 3, characterized in that m is an integer from 1 to 4, preferably m is equal to 1, 2 or 3.

5. A method for manufacturing a compound of formula (I) as defined in any one of claims 1 to 4, comprising successively: a reaction step of a compound of formula (II): in which the groups Ri, F¾, R3 and R4 and n are such as defined in claim 1; with an α,β-unsaturated nitrile; a hydrogenation reaction; the product from these steps being capable of reacting in series (m-1) times with α,β-unsaturated nitrile and then with dihydrogen, m being as defined in claim 1.

6. A process according to claim 5, characterized in that the α,β-unsaturated nitrile is selected from acrylonitrile and methacrylonitrile, preferably acrylonitrile.

7. A process according to claim 5 or 6, characterized in that the molar ratio of α,β-unsaturated nitrile to the compound of formula (II) varies from 0.8 to 1.2, preferably from 0.9 to 1.

2.

8. A process according to any one of claims 5 to 7, characterized in that the molar ratio of α,β-unsaturated nitrile to the compound of formula (II) varies from 1.01 to 1.

1.

9. A process according to any one of claims 5 to 8, characterized in that the reaction of said compound of formula (II) with α,β-unsaturated nitrile is carried out in the presence of at least one basic catalyst (CB).

10. A process according to claim 9, characterized in that the basic catalyst (CB) is selected from alkali and alkaline earth hydroxides, alkali alcoholates, alkali hydrides, basic resins and quaternary ammonium hydroxides, and, preferably, the basic catalyst (CB) is selected from sodium hydroxide, potassium hydroxide, sodium hydride and potassium hydride.

11. A process according to any one of claims 5 to 10, characterized in that said process comprises, prior to the successive steps of reaction of the compound of formula (II), as defined in claim 5, with an α,β-unsaturated nitrile and hydrogenation, a step of reaction of an alcohol of formula (III): where Ri and R2 are as defined in claim 1, with n composed of formula (IV): (IV) in which: Groups R3 and R4 are as defined in claim 1, and n is as defined in claim 1.

12. Compound of formula (V) (V) in which: the groups Ri , R2, R3, 4, R5, 6 and R7 are as defined in claim 1; n is such as defined in claim 1.

13. Compound of formula (VI): (VI) in which: the groups Ri , R2, R3, R4, R5, R6 and R7 are as defined in claim 1; n and m are as defined in claim 1.

14. Use of a compound of formula (I) as defined in any one of claims 1 to 4, as a lubricant, cationic surfactant, flotation collector for ores, corrosion inhibitor, fuel additive and crosslinking agent for epoxy resins.