Manufacturing process for quaternary ammonium carboxylate compounds and additive for coolant emulsions obtainable therefrom

Description

[0001] The invention relates to a manufacturing process for quaternary ammonium carboxylate compounds, the use of an organic quaternary ammonium carboxylate compound A-Carb as an additive in a cooling lubricant emulsion for machine tools, and a polymer with repeating units comprising quaternary ammonium groups with carboxylate ions as counter-ions. The invention further relates to a cooling lubricant comprising the polymer and an apparatus for carrying out the process.

[0002] In machining processes, workpieces are given a specific shape by mechanically removing excess material in the form of chips using a tool. Machining processes include, for example, turning, milling, drilling, and grinding. Due to friction, the applied mechanical work is almost entirely converted into heat.

[0003] Cooling lubricant emulsions, or CSM emulsions for short, are widely used in the metalworking industry for machining. CSM emulsions typically contain an oil component, buffer components, emulsifiers, and various additives. CSM concentrates are homogeneous liquid products with an oily consistency.

[0004] Coolant emulsions are used to cool and lubricate the workpiece and / or tool being machined. For this purpose, the coolant emulsions are typically pumped from a tank and applied to the tool or workpiece. The coolant emulsion is then collected and recirculated. During use, the coolant emulsion is collected and carried away along with chips from the machining process. The coolant emulsion adheres to the carried-away chips.

[0005] Before reusing the coolant emulsion, it must be cleaned of chips and other contaminants. Furthermore, the fine spraying of the coolant emulsion at the high pressures used in the machines leads to water evaporation. This results in a significant loss of coolant emulsion and, at the same time, an increase in the concentration of active components such as oils, additives, and the like in the coolant emulsion due to evaporation.

[0006] To compensate for the removed coolant emulsion and water evaporation, coolant emulsion of low concentration must be replenished regularly, a process known as "replenishment".

[0007] From GB 2547056 A, a system for determining the state of a liquid in a tank is known. The system comprises one or more sensors, each of which can determine a property of the liquid. Depending on the measured properties, the system determines the quantity of concentrate and / or water that must be added to achieve a desired state of the liquid.

[0008] US 5,389,546 describes a continuous titration method for determining the alkalinity of a metalworking fluid. The method involves continuously taking a sample of the metalworking fluid, mixing it with a continuously increasing flow of a standard solution, and continuously determining the pH value. The alkalinity can be calculated from the ratio of the two volume flows. The fluid flow during the measurement is continuously discarded. Alternatively, a sample with a known pH value can be added to verify the reading of a sensor.

[0009] WO 2020 / 126257 discloses a method for determining at least one parameter and / or conditioning a cooling lubricant emulsion for machine tools, wherein the cooling lubricant emulsion is provided in a tank, cooling lubricant emulsion is withdrawn from the tank, and at least one parameter of the cooling lubricant emulsion is detected using at least one sensor. An apparatus for carrying out the method is also disclosed. US3024283 describes a process for producing quaternary ammonium acetates from the corresponding chlorides using an ion exchanger. A solution of the quaternary ammonium compound is passed over a column of a cation exchanger. The column is then washed with an acid solution.

[0010] One difficulty with many coolant emulsions is that, during the operation of a machine tool and with regular replenishment with fresh coolant emulsion, they tend to foam due to the accumulation of certain components. This foaming can be detrimental in several ways.

[0011] Firstly, foam formation prevents a reliable determination of the coolant emulsion level in the tank, as the foam essentially consists of air surrounded by a thin film of the emulsion. This causes the level sensors to register a level higher than the actual level. This can lead to refilling being delayed or insufficient. Furthermore, the measurement of relevant coolant emulsion parameters, which determine the required refill concentration, is distorted if foam enters the corresponding detectors, such as refractometers and / or conductivity sensors.

[0012] Furthermore, foam formation prevents the efficient removal of chips from the coolant emulsion, as some remain on the foam surface. This creates a risk of damage to the machine tools and workpieces due to metal chips being reintroduced into the machine tool, increasing wear. Additionally, foam can reduce the effectiveness of the coolant emulsion in cooling and lubricating the machine tool, as the high air content results in significantly lower cooling capacity and poorer lubricating properties than the coolant emulsion itself. This, too, regularly leads to damage to the machine tool due to increased wear.

[0013] For these reasons, additives are often added to KSS emulsions or their concentrates to disrupt foaming and reduce the tendency of KSS emulsions to foam.

[0014] It has been found that, among other things, certain organic quaternary ammonium salts, especially ammonium halide compounds, can efficiently reduce the tendency of cooling lubricant emulsions to foam even in low concentrations and are therefore suitable as corresponding additives.

[0015] This was found in particular for polymeric quaternary ammonium salts that have repeating units comprising quaternary ammonium groups.

[0016] Several such polymeric quaternary ammonium halide compounds are known under the trivial name "Polyquaternium". These compounds include, for example: copolymers of diallyldimethylammonium chloride and hydroxyethylcellulose (Polyquaternium-4), copolymers of acrylamide and quaternized dimethylammonium ethyl methacrylate (Polyquaternium-5), poly(diallyldimethylammonium chloride) (Polyquaternium-6), copolymers of acrylamide and diallyldimethylammonium chloride (Polyquaternium-7), copolymers of vinylpyrrolidone and quaternized dimethylaminoethyl methacrylate (Polyquaternium-11), homopolymers of quaternized trimethylaminoethyl methacrylate (Polyquaternium-14), copolymers of acrylamide and quaternized dimethylaminoethyl methacrylate (Polyquaternium-15), copolymers of vinylpyrrolidone and quaternized vinylimidazole (Polyquaternium-16), copolymers of acrylic acid and diallyldimethylammonium chloride (Polyquaternium-22),Copolymers of vinylpyrrolidone and methacrylamidopropyl trimethylammonium chloride (Polyquaternium-28), poly(acrylamide-2-methacryloxyethyltrimethylammonium chloride) (Polyquaternium-32), copolymers of quaternized trimethylaminoethyl acrylate and acrylamide (Polyquaternium-33), poly(2-methacryloxyethyltrimethylammonium chloride) (Polyquaternium-37), terpolymers of acrylic acid, acrylamide, and diallyldimethylammonium chloride (Polyquaternium-39), poly[oxyethylene-(dimethyliminio)ethylene(dimethyliminio)ethylene dichloride] (Polyquaternium-42), terpolymers of vinylcaprolactam, vinylpyrrolidone, and quaternized vinylimidazole (Polyquaternium-46), and terpolymers of acrylic acid, methacrylamidopropyltrimethylammonium chloride, and methyl acrylate (Polyquaternium-47).

[0017] Among these, poly[oxyethylene-(dimethyliminio)ethylene(dimethyliminio)ethylenedichloride] (Polyquaternium-42) is particularly suitable as an additive to reduce the tendency of cooling lubricant emulsions to foam.

[0018] However, it has been observed that during prolonged operation of machine tools using coolant emulsions containing these organic quaternary ammonium halide compounds, corrosion of the machine components and the workpieces being processed has occurred to a considerable extent.

[0019] Until now, corrosion could be reduced by regularly replacing and disposing of the entire coolant emulsion before or as soon as the first signs of corrosion appeared. However, this leads to frequent interruptions in the operation of machine tools and large quantities of waste, which is unsatisfactory from both an environmental and economic perspective. Alternatively, the amount of coolant itself in the coolant emulsion can be increased, thereby improving the emulsion's lubricating performance. This can significantly delay corrosion but is associated with increased coolant consumption, which is also undesirable from both an environmental and economic standpoint.

[0020] There is therefore a need for additives for cooling lubricant emulsions that can be used in the same way as the ammonium halide compounds described above, but where corrosion of the machine tools and the workpieces to be processed occurs to a lesser extent.

[0021] Surprisingly, it was found that corrosion can be significantly reduced or even permanently avoided if the halide ions in the additives are at least partially replaced by carboxylate ions.

[0022] One aspect of the invention is therefore the use of an organic quaternary ammonium carboxylate compound, A-Carb, as an additive in a cooling lubricant emulsion for machine tools, preferably to reduce foaming tendency. Preferably, the carboxylate ions are alkyl carboxylate ions with 2 to 5, more preferably 2 to 4, and more preferably 2 to 3 carbon atoms. Acetate ions are particularly preferred.

[0023] As mentioned above, polymeric quaternary ammonium salts containing repeating units comprising quaternary ammonium groups are particularly suitable as additives for reducing foaming tendency. Therefore, the quaternary ammonium carboxylate compound A-Carb used is preferably a liquid or water-soluble polymer P-Carb with repeating units comprising quaternary ammonium groups. For example, the quaternary ammonium carboxylate compound A-Carb used can be one or more of the polymers mentioned above with the trivial name "polyquaternium," in which the halide ions have been at least partially replaced by carboxylate ions.

[0024] To achieve a significant reduction in corrosion, it is stipulated that at least 50 mol%, preferably at least 90 mol%, of the counter-ions of the ammonium groups in the polymer P-Carb are carboxylate ions. It was surprisingly found that a complete exchange of halide ions for carboxylate ions is not necessary for the permanent prevention of corrosion during the operation of machine tools. Therefore, 75 to 99 mol%, more preferably 85 to 98 mol%, and more preferably 90 to 95 mol% of the counter-ions of the ammonium groups in the polymer P-Carb are carboxylate ions.

[0025] Preferably, P-carb polymers comprising repeating units of structure (I) are used. where A +< is selected from cationic groups of structures (A1) and (A2), preferably (A1); B is selected from groups of structures (B1) and (B2), preferably (B1); D is selected from groups of structure (B2); X -< are selected from carboxylate ions, preferably alkyl carboxylate ions with 2 to 5 carbon atoms, and halide ions, preferably chloride ions, wherein at least 50 mol%, preferably at least 90 mol% of the X -< in the polymer P-Carb are carboxylate ions; R 1< are independently selected from alkyl groups with 1 to 4 carbon atoms, preferably methyl; Y is selected from O, S and N(R 2< ), preferably O; R 2< is selected from a hydrogen atom and alkyl groups with 1 to 4 carbon atoms, preferably methyl; n, m and p are selected from 2, 3 and 4; and * denotes the bonding sites of the respective group in the polymer chain.

[0026] Preferably, the polymer P-Carb comprises no further repeating units besides the repeating units of structure (I).

[0027] The polymer P-Carb is preferably present as a solution, more preferably as an aqueous solution, with a concentration of 30 to 99 wt.%, preferably 35 to 90 wt.%, more preferably 40 to 80 wt.%, more preferably 45 to 70 wt.%, more preferably 50 to 65 wt.% of polymer P-Carb, based on the weight of the concentrated solution.

[0028] Concentrated aqueous solutions of the polymer P-Carb, for example, have a density at 20 °C in the range of 1.050 to 1.250 g / cm³, often in the range of 1.100 to 1.200 g / cm³, preferably in the range of 1.120 to 1.180 g / cm³, more preferably in the range of 1.140 to 1.160 g / cm³, and more preferably in the range of 1.145 to 1.154 g / cm³.Furthermore, concentrated aqueous solutions of the polymer P-Carb, for example, have a kinematic viscosity at 20 °C, measured using a Stabinger viscometer in accordance with DIN EN 16896:2017-02, in the range of 350 to 600 mm² / s, often in the range of 400 to 550 mm² / s, preferably in the range of 450 to 500 mm² / s, more preferably in the range of 470 to 490 mm² / s, and / or at 40 °C, measured using a Stabinger viscometer in accordance with DIN EN 16896:2017-02, for example, in the range of 100 to 300 mm² / s, often in the range of 120 to 280 mm² / s, preferably in the range of 150 to 250 mm² / s, more preferably in the range of 190 to 210 mm² / s.

[0029] Preferably, the repeating units of structure (I) have structure (1a) wherein X1 -< is selected from chloride ions and acetate ions, and preferably at least 50 mol%, more preferably at least 80 mol%, more preferably at least 90 mol% of the X1 -< in the polymer P-Carb are acetate ions.

[0030] Particularly preferred is the polymer P-Carb poly(oxyethylene(dimethyliminio)-ethylene-(dimethyliminio)-ethylene-(acetate) x (chloride) y , wherein x has a value of 1.6 to 2, preferably 1.7 to 1.95, more preferably 1.8 to 1.9 and y has a value of 0 to 0.4, preferably 0.05 to 0.3, more preferably 0.1 to 0.2.

[0031] Further objects of the invention are a cooling lubricant comprising the polymer P-Carb, preferably in an amount of 0.05 to 5 wt.%, preferably 0.1 to 2 wt.%, more preferably 0.15 to 1 wt.%, more preferably 0.2 to 0.5 wt.%, based on the weight of the cooling lubricant, and a cooling lubricant emulsion comprising the cooling lubricant, preferably in an amount of 5.5 to 15 wt.%, preferably 6.5 to 9 wt.%, more preferably 7 to 8.5 wt.%, based on the weight of the cooling lubricant emulsion.

[0032] Furthermore, the invention relates to the polymer P-Carb comprising repeating units of structure (I) as described above. This is particularly suitable as an additive for reducing the tendency to foam in cooling-lubricant emulsions while simultaneously reducing corrosion.

[0033] The quaternary ammonium carboxylate compound A-Carb can be obtained by transsalting a quaternary ammonium halide compound A-Halo, for example using an ion exchanger with a cationic stationary phase loaded with carboxylate ions.

[0034] In ion exchange processes, the reactants are typically passed through the ion exchanger in highly diluted form until the exchanger is exhausted. However, this also results in highly diluted products. While these diluted products can be used directly as additives in cooling lubricant emulsions, it is often necessary to store or transport them if they are not used immediately. Storing and transporting highly diluted products is undesirable from both an ecological and economic perspective. This can currently be circumvented by concentrating the diluted products, but this requires additional effort and increased energy consumption.

[0035] Surprisingly, it has now been found that quaternary ammonium carboxylate compounds A-Carb, in particular polymeric quaternary ammonium carboxylate compounds P-Carb, can be obtained in significantly higher concentrations directly from the ion exchange process without an increase in the chloride content of the product when they are placed on the ion exchanger in concentrated form and then forced over the ion exchanger with another fluid.

[0036] Another object of the invention is therefore a method for producing a quaternary ammonium carboxylate compound A-Carb, comprising the steps: a) Passing a quaternary ammonium halide compound A-Halo, preferably a quaternary ammonium chloride compound, through an ion exchange vessel containing an anion exchanger T loaded with carboxylate ions in order to at least partially convert the quaternary ammonium halide compound A-Halo into a quaternary ammonium carboxylate compound A-Carb and to obtain a composition Z1 comprising the ammonium carboxylate compound A-Carb, and to at least partially load the anion exchanger T with halide ions, preferably chloride ions; b) Passing at least one carboxylate-containing regenerant R-Carb through the ion exchange vessel to at least partially load the halide-ion-loaded anion exchanger T with carboxylate ions and to convert the carboxylate-containing regenerant R-Carb into a composition Z2 comprising a halide salt R-Halo; wherein the sequence of steps a) and b) can begin with step a) or step b) and is repeated, and wherein the quaternary ammonium carboxylate compound A-Carb differs from the quaternary ammonium halide compound A-Halo in that the halide ions are at least partially replaced by carboxylate ions, and wherein the ion exchange vessel has at least one first opening and at least one second opening, and the quaternary ammonium halide compound A-Halo in liquid form or as a solution containing at least 30 wt% of the ammonium halide compound A-Halo, based on the weight of the solution, is introduced into the ion exchange vessel through the first opening, and is forced through the ion exchange vessel towards the second opening by introducing at least one other fluid F, preferably deionized water, into the first opening.

[0037] The quaternary ammonium halide compound A-Halo used as a starting material corresponds to the quaternary ammonium carboxylate compound A-Carb to be obtained in the cationic part (quaternary ammonium ion), and differs from it in that the counterions are predominantly halide ions, preferably chloride ions.

[0038] The ammonium halide compound A-Halo is present in liquid or concentrated dissolved form. Preferably, the ammonium halide compound A-Halo is present as an aqueous solution containing 35 to 95 wt.%, more preferably 40 to 85 wt.%, more preferably 45 to 75 wt.%, more preferably 55 to 65 wt.% of the ammonium halide compound A-Halo, based on the weight of the solution.

[0039] The anion exchanger T can be any anion exchanger that enables the exchange of halide ions for carboxylate ions in a salt passed through the ion exchanger. In particular, it is insoluble in the fluid F, the regenerating agent R-Carb, the ammonium halide compound A-Halo, and the ammonium carboxylate compound A-Carb. Suitable anion exchangers are, for example, insoluble polymers that have cationic units whose counterions can be exchanged for halide ions and carboxylate ions. Preferably, the anion exchanger T is a gel-like polymer resin comprising quaternary ammonium groups on its surface. More preferably, the anion exchanger T is a strongly basic anion exchanger.

[0040] Commercially available anion exchangers T are available, for example, under the brand name LEWATIT® from LANXESS. More preferably, the anion exchanger T is a cross-linked, gel-like styrene polymer with quaternary ammonium groups, more preferably with a mean particle size (median volume d50, measured by laser diffraction) of 570 to 670 µm.

[0041] The regenerating agent R-Carb can be any regenerating agent that enables the exchange of halide ions, with which the anion exchanger T is loaded, for carboxylate ions. Known methods for loading anion exchangers with carboxylate ions, such as acetate ions, typically proceed in at least two steps. In a first step, the anion exchanger loaded with halide ions is treated with a strong hydroxide base, e.g., a sodium hydroxide solution, to exchange the halide ions for hydroxide ions. In a second step, the anion exchanger loaded with hydroxide ions is reacted with a carboxylic acid, such as acetic acid, to exchange the hydroxide ions for carboxylate ions, such as acetate ions.

[0042] Surprisingly, it has now been discovered that regeneration can be carried out in a single-stage process when concentrated solutions of metal carboxylates are used as the regenerating agent. This is particularly advantageous because metal carboxylates are significantly less expensive than the corresponding carboxylic acids (e.g., acetic acid) and metal bases (e.g., sodium hydroxide). Furthermore, unlike the corresponding carboxylic acids and metal bases, metal carboxylates are typically not hazardous substances, which further simplifies handling. Additionally, a process step in the regeneration of the anion exchanger is eliminated, which is beneficial from a process economics perspective.

[0043] Therefore, a metal carboxylate is advantageously used as the regenerating agent R-Carb, wherein this is used as a solution, preferably as an aqueous solution, comprising 20 to 40 wt.%, preferably 23 to 38 wt.%, more preferably 28 to 33 wt.%, based on the weight of the solution, of metal carboxylate, preferably alkali metal carboxylate, more preferably sodium acetate.

[0044] Such a regenerating agent can be produced, for example, by dissolving 20 to 40 parts by weight, preferably 23 to 38 parts by weight, more preferably 28 to 33 parts by weight of the solvent-free metal carboxylate in 60 to 80 parts by weight, preferably 62 to 77 parts by weight, more preferably 67 to 72 parts by weight of solvent, in particular water.

[0045] Alternatively, a correspondingly larger amount of a solvent complex of the metal carboxylate can be dissolved in a correspondingly smaller amount of the solvent. For example, sodium acetate in the form of an aqueous solution comprising 20 to 40 wt.%, preferably 23 to 38 wt.%, more preferably 28 to 33 wt.% sodium acetate can be prepared by dissolving 20 to 40 wt. parts, preferably 23 to 38 wt. parts, more preferably 28 to 33 wt. parts sodium acetate in 60 to 80 wt. parts, preferably 62 to 77 wt. parts, more preferably 67 to 72 wt. parts water, or by dissolving 33 to 66 wt. parts, preferably 38 to 63 wt. parts, more preferably 46 to 55 wt. parts sodium acetate trihydrate in 34 to 67 wt. parts, preferably 37 to 62 wt. parts, more preferably 45 to 54 wt. parts water.

[0046] The halide salt R-Halo, which is formed during the regeneration of the anion exchanger, is a salt of the cation of the regenerating agent used and the halide anion with which the anion exchanger T was loaded before regeneration. For example, when a chloride-loaded anion exchanger T is regenerated with sodium acetate, the halide salt R-Halo is sodium chloride. The halide salt R-Halo typically emerges from the ion exchange vessel as composition Z2, containing the halide salt R-Halo, unreacted regenerating agent R-Carb, and fluid F.

[0047] The fluid F used to force the ammonium halide compound A-Halo through the ion exchange vessel can be any fluid suitable for this purpose. Preferably, the fluid F is a liquid, more preferably a solvent, that can flush the ammonium halide compound A-Halo, the ammonium carboxylate compound A-Carb, the regenerating agent R-Carb, and the halide salt R-Halo from the anion exchanger. More preferably, the fluid F is deionized water.

[0048] The ion exchange vessel used for the process according to the invention can be any vessel suitable for ion exchange, and which has at least one first opening and at least one second opening through which components can enter and exit the ion exchange vessel. It is provided that the anion exchanger T cannot exit the ion exchange vessel during the execution of the process.

[0049] Accordingly, the ion exchange vessel is designed to have means that prevent the anion exchanger T from escaping. For example, the openings of the ion exchange vessel can contain filtration media such as frits, which have a pore size smaller than the grain size of the anion exchanger T.

[0050] Preferably, the first opening is positioned on the opposite side from the second opening, so that a fluid passed through the ion exchange vessel can flow through substantially the entire vessel. More preferably, the ion exchange vessel is a tube with the first opening at one end and the second opening at the other end. More preferably, the ion exchange vessel is a column with the first opening at the top and the second opening at the bottom.

[0051] In the context of the invention, "tube" means a vessel with parallel side walls (e.g., the lateral surface of a cylinder) and openings at both ends of the side walls (e.g., the base of a cylinder). Preferably, a tube has a substantially round cross-section (cylindrical shape). In the context of the invention, "column" means a vertical tube.

[0052] The length of the ion exchange vessel in the context of the invention is the distance d between the first opening and the second opening. The diameter of the ion exchange vessel in the context of the invention is the distance between the walls of the ion exchange vessel at its widest point, perpendicular to the longitudinal axis.

[0053] The ratio of the length of the ion exchange vessel to the diameter of the ion exchange vessel is preferably in the range of 2:1 to 20:1, more preferably in the range of 2.5:1 to 10:1, more preferably in the range of 3:1 to 5:1, more preferably in the range of 3.5:1 to 4:1, more preferably in the range of 3.6:1 to 3.8:1.

[0054] For example, the length of the ion exchange vessel can be in the range of 50 cm to 300 cm, preferably in the range of 75 cm to 250 cm, more preferably in the range of 100 cm to 200 cm, and more preferably in the range of 125 cm to 150 cm. Furthermore, the diameter of the ion exchange vessel can be, for example, in the range of 3 cm to 100 cm, preferably in the range of 5 cm to 80 cm, more preferably in the range of 10 cm to 60 cm, more preferably in the range of 15 cm to 50 cm, more preferably in the range of 20 cm to 45 cm, and more preferably in the range of 30 cm to 40 cm.

[0055] Such an ion exchange vessel is preferably filled with at least 80 vol%, preferably at least 90 vol%, of the anion exchanger T. This can correspond, for example, to an amount in the range of 0.6 kg to 1 kg, often in the range of 0.7 kg to 0.9 kg, preferably in the range of 0.75 kg to 0.85 kg, more preferably in the range of 0.82 kg to 0.84 kg of the anion exchanger T per liter of the internal volume of the ion exchange vessel.

[0056] The sequence of steps a) and b) in the process according to the invention can begin with step a) or step b), depending on whether the anion exchanger T is loaded with carboxylate ions at the beginning of the process. If the anion exchanger T is not loaded with carboxylate ions, the sequence of steps a) and b) begins with step b). This is also the case, for example, if the anion exchanger T has been newly acquired, since it is usually supplied with chloride ions as counterions. The sequence can, for example, begin with step a) if the anion exchanger T is still loaded with carboxylate ions after regeneration with carboxylate ions from a previous process.

[0057] Furthermore, the sequence of steps a) and b) is repeated; that is, after step a), step b) is performed, and after step b), step a) is performed. The sequence is typically repeated as many times as required, for example, until a desired quantity of quaternary ammonium carboxylate compound A-Carb has been produced, the quaternary ammonium halide compound A-Halo is exhausted, or the apparatus in which the process is carried out requires maintenance. The repetition of the sequence can be resumed at a later time.

[0058] In step a), the quaternary ammonium halide compound A-Halo is passed through the ion exchange vessel containing the anion exchanger T loaded with carboxylate ions in order to at least partially convert the quaternary ammonium halide compound A-Halo into the quaternary ammonium carboxylate compound A-Carb.

[0059] This results in a composition Z1 comprising the ammonium carboxylate compound A-Carb, optionally unreacted ammonium halide compound A-Halo, and optionally other components that were introduced into the ion exchange vessel together with the ammonium halide compound A-Halo or that originated from it. For example, composition Z1 typically also includes solvents if the ammonium halide compound A-Halo was introduced into the first opening of the ion exchange vessel in the form of a solution. Furthermore, the ammonium halide compound A-Halo is forced through the ion exchange vessel by introducing at least one other fluid F, which typically has a different flow rate through the ion exchange vessel than the ammonium halide compound A-Halo and the ammonium carboxylate compound A-Carb, so that mixing with the fluid F cannot be avoided.Therefore, composition Z1 usually also includes fluid F.

[0060] In composition Z1, typically at least 50 mol%, often 75 to 99 mol%, and preferably 85 to 98 mol% of the halide ions of the ammonium halide compound A-Halo are exchanged for carboxylate ions. Exchange rates exceeding 95 mol% are possible by using a small amount of ammonium halide compound A-Halo introduced into the ion exchange vessel, while using a large amount of the regenerating agent R-Carb.

[0061] These areas may be required, for example, in the electronics or semiconductor industries.

[0062] Surprisingly, it was found that for the permanent prevention of corrosion when using quaternary ammonium compounds as an additive in cooling lubricant emulsions, it is sufficient if 90 to 95 mol% of the halide ions are exchanged for carboxylate ions. Therefore, in composition Z1, 90 to 95 mol%, and more preferably 90 to 92 mol%, of the halide ions of the ammonium halide compound A-Halo are exchanged for carboxylate ions. This achieves a balance between the permanent prevention of corrosion and process economy.

[0063] In the case of quaternary ammonium compounds with one ammonium group per molecule, this means that the composition Z1 typically contains at least 50 mol%, often 75 to 99 mol%, preferably 85 to 98 mol%, more preferably 90 to 95 mol%, more preferably 90 to 92 mol%, based on the amount of the quaternary ammonium compounds A-Carb and A-Halo, of quaternary ammonium carboxylate compound A-Carb and at most 50 mol%, often 1 to 25 mol%, preferably 2 to 15 mol%, more preferably 5 to 10 mol%, more preferably 8 to 10 mol%, based on the amount of the quaternary ammonium compounds A-Carb and A-Halo, of quaternary ammonium halide compound A-Halo.

[0064] In polymeric quaternary ammonium compounds, this means that in most molecules a partial exchange of ions has taken place, and on average at least 50 mol%, often 75 to 99 mol%, preferably 85 to 98 mol%, more preferably 90 to 95 mol%, more preferably 90 to 92 mol% of the counterions are carboxylate ions, and at most 50 mol%, often 1 to 25 mol%, preferably 2 to 15 mol%, more preferably 5 to 10 mol%, more preferably 8 to 10 mol% of the counterions are halide ions.

[0065] The proportion of halide ions in the quaternary ammonium compounds and in composition Z1 can be determined, for example, by X-ray fluorescence analysis.

[0066] In step b), the carboxylate-containing regenerant R-Carb is passed through the ion exchange vessel to at least partially load the halide-ion-loaded anion exchanger T with carboxylate ions and to convert the carboxylate-containing regenerant R-Carb into a composition Z2 comprising a halide salt R-Halo. Composition Z2 can then be collected for other purposes or disposed of properly. Besides the halide salt R-Halo, composition Z2 usually comprises unreacted regenerant R-Carb and, if applicable, other components that were introduced into or formed from the ion exchange vessel along with the regenerant R-Carb. For example, composition Z2 typically also includes solvents if the regenerant R-Carb was used in solution form.

[0067] Furthermore, the regenerant R-Carb is forced through the ion exchange vessel by introducing at least one other fluid F, which typically has a different flow rate through the ion exchange vessel than the regenerant R-Carb and the halide salt R-Halo, so mixing with fluid F cannot be avoided. Therefore, composition Z2 usually also includes fluid F.

[0068] To achieve a sustained ion exchange in the specified ranges, it is advantageous if the weight ratio of regenerating agent R-Carb passed through in step b) to quaternary ammonium halide compound A-Halo passed through in step a) is in the range of 1.5:1 to 20:1, preferably 2:1 to 15:1, more preferably 2.5:1 to 10:1, and more preferably 3:1 to 7:1. This allows essentially the same amount of carboxylate ion-loaded anion exchanger T to be regenerated in step b) over the course of the process as is consumed in step a).

[0069] To force the ammonium halide compound A-Halo through the ion exchange vessel in step a) and subject it to anion exchange, according to the invention, preferably in step a1), a defined quantity M1 of the quaternary ammonium halide compound A-Halo is introduced into the ion exchange vessel through the first opening. Furthermore, preferably in step a2), a defined quantity M2 of the fluid F is also introduced into the ion exchange vessel through the first opening.

[0070] The introduced fluid F displaces the quaternary ammonium halide compound A-Halo towards the second opening and subsequently out of the second opening in the form of composition Z1.

[0071] In step a3), the composition Z1 exiting from the second opening is preferably collected in a collection vessel, the collection being initiated at time t1 and being terminated at time t2.

[0072] To reload the anion exchanger T with carboxylate ions in step b), according to the invention, a defined quantity M3 of the regeneration agent R-Carb is preferably introduced into the ion exchange vessel in step b1). This introduction can be carried out through the first opening or through the second opening of the ion exchange vessel.

[0073] It can be advantageous to introduce the regenerant through the second opening, as this brings the anion exchanger T into contact with the highest concentration of the regenerant R-Carb at the point where it last interacts with the quaternary ammonium halide compound A-Halo. This can help improve the degree of conversion, since the residual amounts of unreacted ammonium halide compound A-Halo, composition Z1, come into contact with a particularly high concentration of carboxylate-laden ion exchanger at the end of the ion exchange vessel. Furthermore, in columns, this has the advantage that the anion exchanger T, which usually has a lower density than the regenerant R-Carb, is less likely to float and become turbulent when the regenerant R-Carb is fed from bottom to top.

[0074] Introducing the regenerant R-Carb through the first opening can be advantageous, as this ensures that all components are guided through the ion exchange vessel in the same direction. This can improve process efficiency, since, for example, it is not necessary to wait until composition Z1 has completely exited the ion exchange vessel before introducing the regenerant R-Carb. This can also reduce the amount of fluid F required for the process.

[0075] Furthermore, this variant does not require any additional means for transporting components from the second opening to the first opening.

[0076] Preferably, in step b2), a defined quantity M4 of fluid F is introduced into the ion exchange vessel. This introduction can be carried out through either the first or the second opening of the ion exchange vessel. Introducing the fluid through the second opening can be advantageous if the regenerant R-Carb was previously introduced through the second opening, as this allows any remaining R-Carb to be completely expelled from the ion exchange vessel through the first opening. However, preferably, in step b2), the fluid F is introduced through the first opening of the ion exchange vessel, regardless of which opening the regenerant R-Carb was introduced through.

[0077] Preferably, in step b3), the composition Z2 comprising the halide salt R-Halo, regenerating agent R-Carb and the fluid F which exits from the first or second opening is collected or disposed of in a vessel other than the collection vessel, wherein the collection or disposal in step b3) is initiated at time t2 and is terminated at time t1 of the subsequent repetition of the sequence of steps a) and b).

[0078] Here, the specified quantity M1 is the quantity of the quaternary ammonium halide compound A-Halo that can be subjected to an exchange of at least 50 mol%, preferably 75 to 99 mol%, more preferably 85 to 98 mol%, more preferably 90 to 95 mol%, more preferably 90 to 92 mol% in the ion exchange vessel loaded with carboxylate ions.

[0079] The quantity M1 can be determined, for example, for the amount of anion exchanger T present in the ion exchange vessel before the start of the process according to the invention. This can be done, for example, by introducing the quaternary ammonium halide compound A-Halo into the ion exchange vessel in small, equal portions and forcing each portion completely through the ion exchange vessel with the fluid F, collecting each portion of the exiting composition in a separate vessel. For each portion, the quantity of chloride ions exchanged for carboxylate ions can be determined.

[0080] The sum of the (chronologically) first collected portions, in which on average at least 50 mol%, preferably 75 to 99 mol%, more preferably 85 to 98 mol%, more preferably 90 to 95 mol%, more preferably 90 to 92 mol% of the anions are carboxylate ions, then corresponds to the quantity M1.

[0081] The specified quantity M2 is the quantity of fluid F sufficient to push the quaternary ammonium halide compound A-Halo and the composition Z1 containing the quaternary ammonium carboxylate compound A-Carb along the distance d between the first opening and the second opening in the direction of the second opening to such an extent that mixing with the subsequently introduced regenerant R-Carb is substantially prevented.

[0082] "Essentially prevented" in the present context means that the composition Z1 exiting the ion exchange vessel contains no more than 5 wt.%, preferably no more than 2 wt.%, more preferably no more than 1 wt.%, based on the weight of composition Z1, of regenerating agent R-Carb and halide salt R-Halo, and that the composition Z2 exiting the ion exchange vessel contains no more than 5 wt.%, preferably no more than 2 wt.%, preferably no more than 1 wt.%, based on the weight of composition Z2, of quaternary ammonium halide compound A-Halo and of quaternary ammonium carboxylate compound A-Carb.

[0083] The quantity M2 can also be determined before the start of the process according to the invention. For example, the ion exchange vessel containing the anion exchanger T loaded with carboxylate ions can first be flushed with fluid F to remove residues of other compounds. Subsequently, the entire quantity M1 of quaternary ammonium halide compound A-Halo, as determined above, is introduced into the ion exchange vessel through the first opening. Then, fluid F is introduced into the first opening to force the quaternary ammonium halide compound A-Halo through the ion exchange vessel. The exiting components are collected in small, equal portions in separate vessels, with each collected portion being assigned the cumulative quantity of fluid F that has been introduced since the start of the introduction of fluid F into the first opening of the ion exchange vessel.The amount of quaternary ammonium compounds A-Carb and A-Halo contained in each portion is determined.

[0084] The amount of fluid introduced, F, is recorded for the portion in which quaternary ammonium compounds A-carb or A-halo are first detected, and for the portion in which no quaternary ammonium compounds A-carb and A-halo are detected. The amount M2 corresponds to the difference between these two amounts.

[0085] Instead of collecting small portions and determining the amount of ammonium compounds, it is also possible to continuously measure one or more parameters of the escaping components, where the parameters for the fluid F and for compositions containing the quaternary ammonium compounds differ. In this case, the amounts of fluid F introduced into the first opening until the beginning of a first change in these parameters (increasing concentration of the quaternary ammonium compounds) and the amount introduced until the end of a second change in these parameters (decreasing concentration of the quaternary ammonium compounds) are recorded. The quantity M2 corresponds to the difference between these two quantities. The parameters can be selected, for example, from the refractive index, the pH value, or the conductivity.

[0086] Alternatively, the quantity M2 can be the quantity of fluid F required to expel the entire quantity M1 of the ammonium halide compound A-Halo from the ion exchange vessel. This alternative is particularly useful if the regenerant is introduced through the second opening of the ion exchange vessel, i.e., in the opposite direction to the ammonium halide compound A-Halo.

[0087] The specified quantity M3 can also be the quantity of the regenerating agent R-Carb required to load the anion exchanger T with carboxylate ions such that the quantity M1 of the quaternary ammonium halide compound A-Halo can undergo an exchange of at least 50 mol%, preferably 75 to 99 mol%, more preferably 85 to 98 mol%, more preferably 90 to 95 mol%, more preferably 90 to 92 mol% of the halide ions for carboxylate ions. This quantity is typically chosen such that the weight ratio M3:M1 is in the range of 1.5:1 to 20:1, preferably 2:1 to 15:1, more preferably 2.5:1 to 10:1, more preferably 3:1 to 7:1.

[0088] The specified quantity M4 is the quantity of fluid F required to push the regenerating agent R-Carb and the composition Z2 comprising the halide salt R-Halo along the distance d through the ion-exchange vessel (101) to such an extent that mixing with the subsequently introduced ammonium halide compound A-Halo is substantially prevented. The quantity M4 can be determined in the same way as the quantity M2, using the quantity M3 of the regenerating agent R-Carb instead of the quantity M1 of the quaternary ammonium halide compound A-Halo.

[0089] Time t1, at which the collection of composition Z1 in a collection vessel is initiated and the collection or disposal of composition Z2, the regenerant R-Carb, and fluid F is terminated, is the time at which composition Z1, containing the quaternary ammonium carboxylate compound A-Carb, begins to flow from the second orifice. Time t2, at which the collection of composition Z1 in a collection vessel is terminated and the collection or disposal of composition Z2, comprising the halide salt R-Halo, unreacted regenerant R-Carb, and fluid F, is initiated, is the time at which composition Z1, containing the quaternary ammonium carboxylate compound A-Carb, ceases to flow from the second orifice.

[0090] Both time points can be determined, for example, before the start of the procedure by performing several, for example three, repetitions of steps a1), a2), b1) and b2), while the outgoing components are collected in small, equal portions in separate containers, with each collected portion being assigned the times since the start of the introduction of each component.

[0091] The amount of quaternary ammonium compound A-carb contained in each sample is determined. The time of collection of the samples in which the quaternary ammonium compound A-carb is first detected corresponds to time t1. The time of collection of the samples in which no quaternary ammonium compound is detected in each repetition corresponds to time t2. After performing the three repetitions, a periodicity can be determined with which times t1 and t2 occur and applied to the method according to the invention.

[0092] Alternatively, the time points can be determined by continuously measuring one or more parameters of the emitted components, where these parameters differ for composition Z1 containing the quaternary ammonium carbonate compound and for composition Z2 containing the halide salt R-Halo. In this case, time t1 is the time at which an increasing concentration of the quaternary ammonium carboxylate compound A-Carb is detected, and time t2 is the time at which the decreased concentration of the quaternary ammonium carboxylate compound A-Carb is detected. The parameters can be selected, for example, from the refractive index, the pH value, or the conductivity. With this alternative, the determination of time points t1 and t2 for each repetition of the sequence of steps a) and b) can be carried out individually and automatically during the process according to the invention.

[0093] A further object of the invention is a device comprising an ion exchange vessel with at least one first opening and at least one second opening arranged at a distance d from each other, and an anion exchanger T between the first opening and the second opening, which is loaded with carboxylate ions or halide ions, a collection vessel for collecting a composition Z1 comprising a quaternary ammonium carboxylate compound A-Carb, at least one means for selectively introducing one of at least three components into the ion exchange vessel, and at least one means for switching on and off the flow of components from the ion exchange vessel into the collection vessel and optionally other vessels, wherein the device is configured to carry out the method according to the invention, preferably automatically.

[0094] The at least one means for selectively introducing one of at least three components can, for example, be a multi-way valve that can be controlled to allow the flow of a component selected from the quaternary ammonium halide compound A-Halo, the fluid F, and the regeneration agent R-Carb. Such a valve is preferably combined with one or more flow meters, for example, oval gear flow meters or turbines, by means of which the introduced quantity of each component can be determined. Alternatively, individual valves, for example, solenoid valves, can be used for each of the components. These are preferably also combined with one or more flow meters.

[0095] Furthermore, the means can be volumetric pumps, each delivering one of at least three components into the ion exchange vessel, or combinations of controllable pumps and flow meters. Combinations of the aforementioned means can also be used.

[0096] When valves are used as a means for the selective introduction of one of at least three components, the quaternary ammonium halide compound A-Halo, the fluid F, and the regenerant R-Carb, for example, can be drawn from pressurized sources. Such sources could be, for example, reservoirs into which compressed air is introduced to force the quaternary ammonium halide compound A-Halo, the fluid F, or the regenerant R-Carb through the valves. Alternatively, such sources could be, for example, reservoirs positioned above the ion exchange vessel, so that the hydrostatic pressure of these reservoirs forces the quaternary ammonium halide compound A-Halo, the fluid F, or the regenerant R-Carb through the valves.

[0097] The at least one means for switching on and off the flow of components from the ion exchange vessel into the collection vessel and optionally other vessels can be any means suitable for this purpose.

[0098] For example, a combination of several valves, such as solenoid valves, can be used to allow or prevent flow in specific directions. Alternatively, a multi-way valve can be used, which can be regulated to allow flow into the collection container, one or more other containers, or for disposal.

[0099] Furthermore, the device according to the invention can have one or more sensors that determine at least one parameter of the components exiting the ion exchange vessel. These parameters can be, for example, a refractive index, a conductivity, or a pH value of the components. Accordingly, the at least one sensor can be selected, for example, from a refractometer, preferably a process refractometer, a pH meter, and a conductivity sensor. It is intended that the sensor is selected such that the value of the determined parameter differs for composition Z1 and for other exiting components.

[0100] Furthermore, the device according to the invention can include a control unit that controls the method according to the invention and enables it to run automatically. The control unit can, for example, comprise a microprocessor, a microcontroller, an ASIC (application-specific integrated circuit), an FPGA (field-programmable gate array), and / or a computer. Preferably, the control unit is a computer. Brief description of the characters

[0101] Exemplary embodiments of the invention and the underlying principles are illustrated in the drawings and explained in more detail in the following description. The drawings show: FIG. 1 a schematic representation of the exchange of chloride ions for acetate ions, FIG. 2 A visualization of the assessment criteria for determining corrosion behavior using the chip test method with grey cast iron chips according to DIN 51360-2:1981-07 FIG. 3a schematic representation of an embodiment of the device according to the invention, FIG. 4 a schematic representation of a further embodiment of the device according to the invention, FIG. 5 a schematic representation of a third embodiment of the device according to the invention, FIG. 6 a schematic representation of the process of an embodiment of the method according to the invention, FIG. 7 a schematic representation of the process of a further embodiment of the method according to the invention, FIG. 8 a schematic representation of the process of a third embodiment of the method according to the invention.

[0102] In the following description of exemplary embodiments of the invention, identical or similar components are designated by the same reference numerals, and repeated descriptions of these components are omitted in individual cases. The figures represent the subject matter of the invention only schematically.

[0103] FIG. 1 Figure 1 shows a simplified schematic representation of the exchange of chloride ions for acetate ions. In this example, the anion exchanger T is a stationary phase with trialkylammonium groups bonded to it, where the anion exchanger T is represented by a black bar and the trialkylammonium groups are represented as NR 3 +<. R is alkyl, preferably methyl. The anion exchanger T is loaded with acetate ions and becomes loaded with chloride ions during the salting process. A polymeric compound P-Halo, poly[oxyethylene(dimethyliminio)ethylene(dimethyliminio)ethylenedichloride], is shown as the quaternary ammonium halide compound A-Halo. After salting in the ion exchanger, the polymeric quaternary ammonium carboxylate compound P-Carb, poly[oxyethylene(dimethyliminio)ethylene(dimethyliminio)ethylenediacetate], is obtained.

[0104] FIG. 2Figure 1 shows a visualization of the assessment criteria for determining corrosion behavior using the chip test method with grey cast iron chips according to DIN 51360-2:1981-07. This method was applied in the exemplary embodiments to determine the degree of corrosion.

[0105] FIG. 3Figure 1 shows an embodiment of the device 100 according to the invention, comprising an ion exchange vessel 101 filled with an anion exchanger T (shown as hatching). The ion exchange vessel 101 is designed as a column having a first opening 102 at its upper end and a second opening 103 at its lower end, arranged at a distance d from each other. The device 100 further comprises a collection vessel 200 for the composition Z1, a further vessel 300 for the other exiting components, a solenoid valve 201 which can allow or prevent the flow from the second opening 103 of the ion exchange vessel 101 into the collection vessel 200, and a solenoid valve 301 which can allow or prevent the flow from the second opening 103 of the ion exchange vessel 101 into the further vessel 300.Furthermore, the device 100 comprises a storage vessel 400 containing the quaternary ammonium halide compound A-Halo, a storage vessel 500 containing the regenerating agent R-Carb, a storage vessel 600 containing the fluid F, a volumetric pump 401 capable of introducing a defined quantity M1 of the ammonium halide compound A-Halo from the storage vessel 400 into the first opening 102 of the ion exchange vessel 101, a volumetric pump 501 capable of introducing a defined quantity M3 of the regenerating agent R-Carb from the storage vessel 500 into the first opening 102 of the ion exchange vessel 101, and a volumetric pump 601 capable of introducing a defined quantity M2 or a defined quantity M4 of the fluid F from the storage vessel 500. 600 can be introduced into the first opening 102 of the ion exchange vessel 101.A control unit (not shown) is configured to actuate valves 201 and 301, opening or closing them, and to actuate volumetric pumps 401, 501, and 601, causing them to pump or refrain from pumping the respective components. The control unit is configured so that only one of valves 201 or 301 is open at any given time, and only one of the volumetric pumps 401, 501, or 601 pumps the respective component. The sequence in which pumps 401, 501, and 601 pump the components, as well as the quantities of each component, are determined in advance and programmed into the control unit. The time t1, at which valve 201 opens and valve 301 closes, and the time t2, at which valve 201 closes and valve 301 opens, are also determined in advance and programmed into the control unit.

[0106] FIG. 4shows a further embodiment of the device 100 according to the invention. This differs from the device according to FIG. 3by using a solenoid valve 402 in combination with a flow meter 403 instead of the volumetric pump 401, a solenoid valve 502 with a flow meter 503 instead of the volumetric pump 501, and a solenoid valve 602 with a flow meter 603 instead of the volumetric pump 601. The storage vessels 400, 500, and 600 are pressurized, for example, by introducing compressed air into them (not shown). Furthermore, the ion exchange vessel 101 includes a sensor 104 that can determine at least one parameter of the components exiting the second opening 103. For example, the sensor 104 is a conductivity sensor. The control unit (not shown) is configured to actuate the valves 201, 301, 402, 502, and 602 so that they are opened or closed.The control unit is configured so that only one of valves 201 or 301 is open at any given time, and only one of valves 402, 502, or 602 is open at any given time. The sequence in which valves 402, 502, and 602 open and close, and the quantities of the respective components, are determined in advance and programmed into the control unit. When the specified quantity is detected by the corresponding flow meter 403, 503, or 603, respectively, with valve 402, 502, or 602 open, the valve closes. Time t1, at which valve 201 opens and valve 301 closes, is the time at which sensor 104 detects an increase in conductivity, which was determined in advance for composition Z1. Time t2, at which valve 201 closes and valve 301 opens, corresponds to the time at which the conductivity has decreased again.

[0107] FIG. 4shows a further embodiment of the device 100 according to the invention. This differs from the device according to FIG. 3 The volumetric pump 501 introduces the regeneration agent R-Carb from the storage vessel 500 through the second opening 103 of the ion exchange vessel 101. The device 100 includes a further solenoid valve 302, which can allow or prevent the flow from the first opening 102 of the ion exchange vessel 101 into the further vessel 300. The control unit (not shown) is configured to actuate the valves 201, 301, and 302, opening or closing them, and to actuate the volumetric pumps 401, 501, and 601, causing them to pump or refrain from pumping the respective components.

[0108] The control unit is configured so that only one of the valves 201, 301, or 302 is open at any given time, and only one of the volumetric pumps 401, 501, or 601 pumps the respective component. When volumetric pump 501 is operating, valves 201 and 301 are always closed, and valve 302 is open. When volumetric pump 301 or 601 is operating, valve 302 is always closed, and one of the valves 201 or 301 is open. Otherwise, the volumetric pumps and valves 201 and 301 are controlled as for FIG. 3 described.

[0109] FIG. 6, 7 and 8Each figure shows a schematic representation of the sequence of an embodiment of the method according to the invention. The figure shows a section of the method in which a repetition (1 cycle) of steps a) and b) of the method or of steps a1), a2), a3), b1), b2), and b3) is shown. In this representation, the sequence of steps a) and b) begins with step b). The horizontal axis represents the time axis, on which the time points t1 and t2 are marked. The temporal sequence of the method is divided into three strips. The upper strip identifies the components that enter and exit through the first opening 102 of the ion exchange vessel 101, and the lower strip identifies the components that enter and exit through the second opening 103 of the ion exchange vessel 101.

[0110] The black arrows indicate the direction in which the components are moved. The middle strip shows the approximate time course of the distance d between the first opening 102 and the second opening 103 of the ion exchange vessel 101, which the individual components travel within the ion exchange vessel 101. Since fluid F interacts with the ion exchanger T to a lesser extent than the other components, its flow velocity is higher, so that some of fluid F is partially contained in compositions Z1 and Z2, and thus the outgoing quantity of compositions Z1 and Z2 is greater than the incoming quantity of quaternary ammonium halide compound A-Halo or the incoming quantity of regenerant R-Carb. The outgoing quantity of fluid F is correspondingly smaller than the incoming quantity.

[0111] For illustration purposes, the ion exchange vessel 101 with the first opening 102 and the second opening 103 is shown next to the schematic process.

[0112] In FIG.6 The schematic shows the temporal sequence for a process in which the quaternary ammonium halide compound A-Halo, the fluid F and the regenerating agent R-Carb are introduced through the first opening 102 of the ion exchange vessel 101, as is the case, for example, in the devices according to FIG. 3 and FIG. 4 This is the case. The exit of composition Z1 containing the quaternary ammonium carboxylate compound A-Carb, fluid F, or composition Z2 containing the halide salt R-Halo from the second opening 103 occurs at a time delay compared to the introduction of the ammonium halide compound A-Halo, fluid F, or regenerating agent R-Carb.

[0113] Since all components are introduced through the first opening 102, it is not necessary to wait until the entire composition Z1 has exited the second opening 103 before introducing the regenerating agent R-Carb, nor is it necessary to wait until the entire composition Z2 has exited the second opening 103 before introducing the quaternary ammonium halide compound A-Halo. It is sufficient if the fluid F creates a sufficient distance between composition Z1 and the regenerating agent R-Carb to substantially prevent their mixing.

[0114] In FIG. 7 The schematic shows the temporal sequence for a process in which only the regeneration agent R-Carb is introduced into the ion exchange vessel 101 through the second opening 103, as is the case, for example, with the device according to FIG. 5This is the case. In this embodiment, it is necessary to wait until the entire composition Z1 has exited the second opening 103 before introducing the regenerating agent R-Carb into the second opening 103.

[0115] In FIG. 8 The schematic diagram shows the temporal sequence for a process in which, in addition to the regenerating agent R-Carb, fluid F is also introduced into the ion exchange vessel 101 through the second opening 103. In this embodiment, it is also necessary to wait until the entire composition Z2 has exited the first opening 102 before the quaternary ammonium halide compound A-Halo is introduced into the first opening 102. To ensure this, the process is delayed until only fluid F exits the first opening 102.

[0116] The Figures 1-8 , Examples and claims explain the invention. Examples

[0117] Poly[oxyethylene-(dimethyliminio)ethylene(dimethyliminio)ethylenedichloride] (P-Halo) was used as the quaternary ammonium halide compound A-Halo. This was used in the form of a 60 wt% aqueous solution. The aqueous solution was purchased from Buckman Laboratories International, Inc. as EBC-1. The chloride content is approximately 17 wt%, based on the aqueous solution. The kinematic viscosity, measured with the "SVM 3001 Stabinger Viscometer" (Anton Paar) according to DIN EN 16896:2017-02, of the aqueous solution at 20 °C is 483 mm² / s, and at 40 °C it is 198 mm² / s. The solution was used undiluted.

[0118] The regenerating agent R-Carb was a solution of 50 parts by weight of sodium acetate trihydrate in 50 parts by weight of deionized water.

[0119] Deionized water was used as fluid F.

[0120] The anion exchanger T (LEWATIT® MonoPlus M500) was acquired by LANXESS Deutschland GmbH and is a cross-linked, gel-like copolymer resin of styrene and divinylbenzene with quaternary ammonium groups bonded to it. In its acquired state, the anion exchanger T was loaded with chloride ions. Example 1

[0121] The process for the production of poly[oxyethylene(dimethyliminio)ethylene-(dimethyliminio)ethylenediacetate] as polymeric quaternary ammonium carboxylate compound P-Carb was carried out several times to determine suitable ratios of regenerant R-Carb to polymeric quaternary ammonium halide compound P-Halo.

[0122] The ion exchange vessel was a column with a round cross-section, 130 cm long and 35 cm in diameter. The ion exchange vessel was filled with 100 kg of the anion exchanger.

[0123] It was found that ratios as shown in Table 1 were sufficient for an exchange of more than 90 mol% of the chloride ions. The R-Carb:P-Halo ratio is the net weight ratio (sodium acetate:poly[oxyethylene-(dimethyliminio)ethylene(dimethyliminio)ethylenedichloride]) excluding the water content. The chloride ion content in the starting material and the residual chloride ion content in the product were determined by X-ray fluorescence analysis. Table 1 Amount of sodium acetate trihydrate [g] Quantity EBC-1 [g] R-Carb:P-Halo ratio Residual chloride content 120 35 3,4:1 8.9 mol% 160 35 4,6:1 2.7 mol% 240 35 6,9:1 1.9 mol-% Example 2

[0124] The process for the preparation of poly[oxyethylene(dimethyliminio)ethylene-(dimethyliminio)ethylenediacetate] as the quaternary ammonium carboxylate compound P-Carb was carried out with the parameters shown in Table 2, whereby only the regenerant was introduced into the ion exchange vessel from below and the other components were introduced from above. Since the acquired anion exchanger T was loaded with chloride ions, regeneration step b) was carried out as the first step of the process.

[0125] The ion exchange vessel was a column with a round cross-section, 130 cm long and 35 cm in diameter. The ion exchange vessel was filled with 100 kg of the anion exchanger. Table 2 Step Inflow Run Components Inlet flow rate [L / h] Time [min] Volume [L] b1) R-Carb F, then Z2 F, R-Carb, R-Halo 75 180 225 b2) F Z2 F, R-Carb, R-Halo 200 39 130 a1) P-Halo Z2, then F F, R-Carb, R-Halo 50 12 10 a2) F F F 100 9 15 Z1 P-Carb, F 120 200

[0126] Composition Z1, containing the polymeric ammonium carboxylate compound P-Carb, was detected and collected only in the effluent during the second part of step a2) according to Table 2. The remaining products were collected in a waste container.

[0127] The isolated composition Z1 consisted essentially of poly[oxyethylene-(dimethyliminio)ethylene(dimethyliminio)ethylenediacetate] and water. On average, no more than 10 mol% of the anions were chloride ions.

[0128] The concentration of poly[oxyethylene(dimethyliminio)ethylene(dimethyliminio)ethylenediacetate] in composition Z1 was 3 wt%, based on the composition. Before further use in cooling lubricants, the composition was concentrated to a concentration of 60 wt% to allow comparability with EBC-1.

[0129] Performing the procedure with the modification that the regenerating agent R-Carb is also introduced from above through the ion exchange vessel allows for a significant saving of the fluid quantity in step b2), without substantially changing the properties of the product. Example 3

[0130] A cooling lubricant comprising 0.4 wt.% EBC-1 (net content P-Halo = 0.24 wt.%) as an additive to reduce foaming tendency was produced, and aqueous cooling lubricant emulsions with concentrations of 5.5 to 8.5 wt.% of the cooling lubricant were produced from this.

[0131] In the same way, a cooling lubricant comprising 0.4 wt% of the concentrate produced in Example 2 containing 60 wt% poly[oxyethylene-(dimethyliminio)ethylene(dimethyliminio)ethylenediacetate] (net content P-Carb = 0.24 wt%; 10 mol% chloride in the anions) was prepared, and aqueous cooling lubricant emulsions with concentrations of 5.5 to 8.5 wt% of the cooling lubricant were prepared from this.

[0132] The corrosion behavior of the manufactured cooling lubricant emulsions was investigated before use in a machine tool in accordance with DIN 51360-2:1981-07. The corrosion behavior was rated on a scale of 0 to 4, with the evaluation criteria in FIG. 2 are depicted.

[0133] Furthermore, the cooling-lubricant emulsions were used in machine tools where fresh cooling-lubricant emulsion had to be replenished regularly. No foaming was observed with any of the emulsions. After a total amount of fresh cooling-lubricant emulsion had been replenished, resulting in a fivefold increase in chloride ion concentration, the corrosion behavior was reassessed.

[0134] The results are shown in Table 3. Concentration [wt%] 5,5 6 6,5 7 7,5 8 8,5 assessment Synthetic cooling lubricant with 0.4 wt% P-halo Before enrichment 2 2 1 1 1 0 0 After enrichment 3 3 3 3 2 2 1 Synthetic cooling lubricant with 0.4 wt% P-carb Before enrichment 2 2 1 0 0 0 0 After enrichment 2 2 1 0 0 0 0

[0135] The data show that with the cooling lubricant according to the invention containing P-Carb, even before the operation of the machine tools, lower corrosion phenomena occur from concentrations of 7 wt.% in the emulsion than with the cooling lubricant containing P-Halo.

[0136] After operation of the machine tools and enrichment of chloride ions, the corrosion behavior of the cooling lubricants according to the invention does not change. In contrast, significantly stronger corrosion phenomena occur with the cooling lubricants containing P-halo at all concentrations tested.

Claims

1. A process for the preparation of a quaternary ammonium carboxylate compound A-Carb, comprising the steps of: a) passing a quaternary ammonium halide compound A-Halo, preferably a quaternary ammonium chloride compound, through an ion exchange vessel (101) containing an anion exchanger T loaded with carboxylate ions, to at least partially trans-salify the quaternary ammonium halide compound A-Halo into a quaternary ammonium carboxylate compound A-Carb and to obtain a composition Z1 comprising the ammonium carboxylate compound A-Carb, and to load the anion exchanger T at least partially with halide ions, preferably chloride ions; b) passing at least one carboxylate-containing regenerating agent R-Carb through the ion exchange vessel (101) to at least partially load the anion exchanger T, which is loaded with halide ions, with carboxylate ions, and to convert the carboxylate-containing regenerating agent R-Carb into a composition Z2 comprising a halide salt R-Halo; wherein the sequence of steps a) and b) may begin with step a) or step b) and is performed repeatedly, and wherein the quaternary ammonium carboxylate compound A-Carb differs from the quaternary ammonium halide compound A-Halo in that the halide ions are at least partially exchanged for carboxylate ions, wherein the ion exchange vessel (101) has at least a first opening (102) and at least a second opening (103), and the quaternary ammonium halide compound A-Halo in liquid form or as a solution containing at least 30 wt.% of the ammonium halide compound A-Halo, based on the weight of the solution, is introduced into the ion exchange vessel (101) through the first opening (102), and is pushed through the ion exchange vessel (101) from the first opening (102) toward the second opening (103) by introducing at least one other fluid F, preferably deionized water, into the first opening (102).

2. The process according to claim 1, wherein the quaternary ammonium carboxylate compound A-Carb is a liquid or water-soluble polymer P-Carb having repeating units comprising quaternary ammonium groups, wherein at least 50 mol%, preferably at least 90 mol%, of the counterions of the ammonium groups are carboxylates.

3. The process according to claim 2, wherein the polymer P-Carb comprises repeating units of structure (I), wherein A+ is selected from cationic groups of structures (A1) and (A2), preferably (A1); B is selected from groups of structures (B1) and (B2), preferably (B1); D is selected from groups of structure (B2); X- are selected from carboxylate ions, preferably alkyl carboxylate ions having 2 to 5 carbon atoms, and halide ions, preferably chloride ions, wherein at least 50 mol%, preferably at least 90 mol%, of the X- in the polymer P-Carb are carboxylate ions; R1 are independently selected from alkyl groups having 1 to 4 carbon atoms, preferably methyl; Y is selected from O, S, and N(R2), preferably O; R2 is selected from a hydrogen atom and alkyl groups having 1 to 4 carbon atoms, preferably methyl; n, m, and p are selected from 2, 3, and 4; and * denotes the binding sites of the respective group in the polymer chain.

4. The process according to claim 3, wherein the repeating units of structure (I) have the structure (la) wherein X1- is selected from chloride ions and acetate ions, and preferably at least 50 mol%, more preferably at least 80 mol%, more preferably at least 90 mol% of the X1- in the polymer P-Carb are acetate ions.

5. The process according to any one of claims 1 to 4, wherein the regenerating agent R-Carb is a metal carboxylate, preferably sodium acetate, which is present in the form of an aqueous solution comprising 20 to 40 wt.%, preferably 23 to 38 wt.%, more preferably 28 to 33 wt.%, based on the weight of the aqueous solution, of the metal carboxylate.

6. The process according to any one of claims 1 to 5, wherein the weight ratio of regenerating agent R-Carb passed through in step b) to quaternary ammonium halide compound A-Halo passed through in step a) is in the range of 1.5:1 to 20:1, preferably 2:1 to 15:1, more preferably 2.5:1 to 10:1, more preferably 3:1 to 7:1.

7. The process according to any one of claims 1 to 6, wherein the quaternary ammonium halide compound A-Halo is liquid or is in the form of an aqueous solution comprising 35 to 95 wt.%, preferably 40 to 85 wt.%, more preferably 45 to 75 wt.%, more preferably 55 to 65 wt.%, based on the weight of the aqueous solution.

8. The process according to any one of claims 1 to 7, wherein the anion exchanger T is a gel-like styrene polymer having quaternary ammonium groups bound thereto.

9. The process according to any one of claims 1 to 8, wherein in the ion exchange vessel (101) the first opening (102) and the second opening (103) are arranged at a distance d from one another, wherein step a) is performed by: a1) introducing a predetermined amount M1 of the quaternary ammonium halide compound A-Halo into the ion exchange vessel (101) through the first opening (102); a2) introducing a predetermined amount M2 of the fluid F into the ion exchange vessel (101) through the first opening (102), a3) collecting the composition Z1 exiting from the second opening (103) in a collection vessel (200), beginning at a time t1 and ending at a time t2; wherein step b) is performed by: b1) introducing a predetermined amount M3 of the regenerating agent R-Carb into the ion exchange vessel (101) through the first opening (102) or the second opening (103); b2) introducing a predetermined amount M4 of the fluid F through the first opening (102) or the second opening (103), b3) collecting composition Z2 and fluid F, which exit from the first opening (102) or the second opening (103), in a vessel (300) other than the collection vessel (200), or disposing of them, beginning at time t2 and ending at time t1 of the subsequent repetition of the sequence of steps a) and b), where the predetermined quantities are as follows: M1 is the amount of the quaternary ammonium halide compound A-Halo, which can be subjected to an exchange of at least 50 mol%, preferably at least 90 mol%, of the halide ions for carboxylate ions with the amount of carboxylate-loaded anion exchanger T contained in the ion exchange vessel (101); M2 is the amount of fluid F sufficient to push the quaternary ammonium halide compound A-Halo and the composition Z1 containing the ammonium carboxylate compound A-Carb along the distance d through the ion exchange vessel (101) to such an extent that mixing with the subsequently introduced regenerating agent R-Carb is essentially prevented; M3 is the amount of regenerating agent R-Carb required to load the anion exchanger T with carboxylate ions, such that the amount M1 of the quaternary ammonium halide compound A-Halo can be subjected to an exchange of at least 50 mol%, preferably at least 90 mol% of the halide ions for carboxylate ions, wherein preferably the weight ratio M3:M1 is in the range of 1.5:1 to 20:1, more preferably 2:1 to 15:1, more preferably 2.5:1 to 10:1, more preferably 3:1 to 7:1; M4 is the amount of fluid F required to push the regenerating agent R-Carb and the composition Z2 comprising the halide salt R-Halo along the distance d through the ion exchange vessel (101) to such an extent that mixing with the subsequently introduced ammonium halide compound A-Halo is essentially prevented; and wherein the time t1 is the time at which the composition Z1 containing the quaternary ammonium carboxylate compound A-Carb begins to exit the second opening (103), and the time t2 is the time at which the composition Z1 containing the quaternary ammonium carboxylate compound A-Carb ceases to exit the second opening (103).

10. The use of an organic quaternary ammonium carboxylate compound A-Carb, as defined in any one of claims 2 to 4, or obtainable by the method according to any one of claims 2 to 9, as an additive in a cooling lubricant emulsion for machine tools, preferably for reducing the tendency to foam.

11. A cooling lubricant comprising the polymer P-Carb as defined in any one of claims 2 to 4, preferably in an amount of 0.05 to 5 wt.%, preferably 0.1 to 2 wt.%, more preferably 0.15 to 1 wt.%, more preferably 0.2 to 0.5 wt.%, based on the weight of the cooling lubricant.

12. A cooling lubricant emulsion comprising the cooling lubricant according to claim 11, preferably in an amount of 5.5 to 15 wt.%, more preferably 6.5 to 9 wt.%, more preferably 7 to 8.5 wt.%, based on the weight of the cooling lubricant emulsion, and water.

13. Polymer P-Carb, as defined in claim 3 or 4.

14. Apparatus (100) comprising an ion exchange vessel (101) having at least a first opening (102) and at least a second opening (103) arranged at a distance d from one another, and an anion exchanger T between the first opening (102) and the second opening (103), which is loaded with carboxylate ions or halide ions, a collection vessel (200) for collecting a composition Z1 comprising a quaternary ammonium carboxylate compound A-Carb, at least one means (401, 402, 501, 502, 601, 602) for selectively introducing one of at least three components into the ion-exchange vessel (101), and at least one means (201) for turning on and off the flow of components from the ion exchange vessel (101) into the collection vessel (200) and optionally other vessels (300), wherein the apparatus is configured to perform the method according to any one of claims 5 to 9.

15. A device (100) according to claim 14, further comprising at least one sensor (104) at the second opening (103), for determining at least one parameter, preferably the refractive index, conductivity, or pH value, of composition Z1 and other components emerging from the second opening (103), wherein the value of the at least one parameter differs for composition Z1 and for the other components exiting the second opening (103).