Sacrificial zwitterions in low conductivity heat transfer fluids

Abstract

The present invention relates to heat transfer fluids comprising zwitterions that act as sacrificial agents when placed in contact with ion exchange resins, thereby preventing uptake of desired additives such as corrosion inhibitors or dyes. The invention further relates to related methods, compositions and uses.

Description

Sacrificial zwitterions in low-conductivity heat transfer fluids Technical Field

[0001] This invention relates to heat transfer fluids containing zwitterionic ions. The invention further relates to a method of exchanging heat, comprising circulating a heat transfer fluid containing a zwitterionic compound through a cooling system containing an ion exchange resin. The invention further relates to components containing said heat transfer fluid and their uses, for example, in battery or fuel cell unit electric vehicles. Background Technology

[0002] Heat transfer fluids are widely used in heat exchange systems related to internal combustion engines, solar energy systems, fuel cell units, electric motors, generators, electronic devices, and battery devices. Heat transfer fluids typically consist of a base fluid and one or more additives.

[0003] Historically, water has been the preferred base fluid due to its heat transfer properties. In many applications, antifreeze properties are required, and in such cases, a base fluid consisting of water mixed with freezing point depressants (like alcohols, glycols, or salts) is used. Additives present in heat transfer fluids can be used to achieve various functions, such as (further) lowering the freezing point, improving heat exchange characteristics, and inhibiting corrosion. Because heat transfer fluids are in continuous contact with metal parts (aluminum alloys, cast iron, steel, copper, brass, solder, etc.), they almost always contain one or more corrosion inhibitors.

[0004] Alternative energy technologies, such as battery electric vehicles or fuel cell unit electric vehicles and power plants, have become an attractive alternative to combustion engines due to their relatively low pollutant output, and their development and use have increased the need for new heat transfer fluids.

[0005] A fuel cell unit is an electrochemical cell in which stored chemical energy is converted into electrical energy through the controlled oxidation of fuel. In most applications, several electrochemical cells are stacked in series to form a so-called fuel cell stack, allowing for higher voltages. The heat generated by the fuel cell stack can be removed by allowing heat transfer fluid to flow through channels formed by the bipolar plates.

[0006] The potential difference between the positive and negative terminals of a fuel cell stack can cause shunt current to flow through the heat transfer fluid, thereby reducing the voltage of the fuel cell unit. In addition to harmful voltage loss, shunt current also causes other problems, such as corrosion of the separator near the positive terminal of the fuel cell stack.

[0007] A battery is an electrochemical cell in which stored chemical energy is converted into electrical energy through a redox reaction. In most applications, several electrochemical cells are connected in series to form a battery pack, allowing for higher voltages. The heat generated by the battery pack can be removed by allowing a heat transfer fluid to flow through channels inside or outside the battery pack.

[0008] When the heat transfer fluid comes into contact with the current collector (tack) of the battery pack, a safety-critical event may occur, such as a short circuit or electrolysis (leading to the formation of flammable hydrogen gas).

[0009] In motors (such as electric motors), the heat transfer fluid can come into contact with current-carrying components (like copper windings). In this case, power loss or short circuits can cause the device to malfunction.

[0010] Therefore, heat transfer fluids used in electrical applications such as batteries and fuel cell units need to have low electrical conductivity (i.e., high resistance) and should be able to maintain this conductivity throughout the entire lifespan of the heat transfer fluid.

[0011] Most known heat transfer fluids (e.g., coolants) are designed for internal combustion engines and are unsuitable for electrical applications where low conductivity is required for safety reasons, such as fuel cell units, batteries, motors, or power electronics, because they (i) have high conductivity, or (ii) become significantly more conductive, especially as they age at elevated temperatures. The increase in conductivity during aging is generally attributed to the degradation of alcohols, particularly diols, which are often used as base fluids, the degradation of additives, metal corrosion, and / or the formation of ionic compounds from impurities in the cooling circuit.

[0012] Therefore, in recent years, there has been increasing interest in developing heat transfer fluids that are better suited for electrical applications such as fuel cell units, batteries, motors, or power electronic devices.

[0013] To extend the duration of low conductivity, in addition to employing specially designed heat transfer fluids, it is common practice to integrate ion exchange resins into the cooling circuit, allowing the heat transfer fluid to circulate through the ion exchange resin. The ion exchange resin functions to remove ionic contaminants that form during the aging of the heat transfer fluid, such as glycolates (ionic degradation products of glycols that form during aging and increase the conductivity of the heat transfer fluid). Heat transfer fluids typically contain ionic or nonionic additives that perform various functions, such as corrosion protection, pH control, reducing oxidation processes in the fluid, dispersing particulate matter, and identifying dyes in the fluid. The inventors of this invention have discovered that the use of such ion exchange resins results in the undesirable removal of polar nonionic and ionic additives from the heat transfer fluid, thereby reducing or eliminating the desired properties provided by such additives. For example, triazole is used as a corrosion inhibitor for red metals but is removed from the heat transfer fluid by ion exchange resins. Therefore, higher concentrations of such additives (e.g., triazole) are needed to compensate for the losses due to the ion exchange resin, otherwise the product performance will deteriorate.

[0014] US 8951689 B2 discloses a coolant circulation channel with an ion exchange resin. When coolant containing an inhibitor (such as mercaptobenzothiazole) flows through the circulation channel, the ion exchange resin removes and adsorbs ions generated in the coolant.

[0015] CN 114214044 A discloses a coolant for a fuel cell unit comprising N,N,N-trimethylglycine and water. The liquid is passed through an ion exchange resin to reduce its conductivity to 0-5 µS / cm, and then used as a heat transfer fluid.

[0016] The object of this invention is to provide a heat transfer fluid that allows the electrical conductivity of the heat transfer fluid to be maintained.

[0017] The object of this invention is to provide a heat transfer fluid that has improved compatibility with ion exchange resins.

[0018] The object of the present invention is to provide a heat transfer fluid that limits or prevents the undesirable removal of one or more additives (such as corrosion inhibitors and / or dyes) by means of an ion exchange resin.

[0019] The object of this invention is to provide a method for exchanging heat and related compositions to improve the compatibility of low-conductivity heat transfer fluids with ion exchange resins. Summary of the Invention

[0020] The inventors of this invention have unexpectedly discovered that zwitterions according to formulas (Ia) and / or (Ib) act as sacrificial agents when placed in contact with ion exchange resins in low-conductivity heat transfer fluids. These zwitterions prevent the uptake of desired functional additives such as corrosion inhibitors and / or dyes present in the heat transfer fluid. Furthermore, the zwitterionic compounds do not significantly increase conductivity. Moreover, as shown in the accompanying examples, the mixture maintains low conductivity that does not change significantly with aging. Unexpectedly, the ion exchange resin can still perform its desired function of absorbing conductivity-increasing products (such as glycolates) formed during aging. Not wishing to be bound by theory, the inventors of this invention believe this is because the ion exchange resin has a greater affinity for zwitterions than for additives in the heat transfer fluid, but less than for oxidative degradation products of the base fluid (such as glycolates). One or more objects of this invention are achieved through the various aspects of the invention described herein.

[0021] Therefore, in a first aspect, the present invention provides a heat transfer fluid comprising: at least one zwitterionic compound according to formula (Ia) or (Ib); Where Y is selected from sulfonate (-SO3) - ), phosphite (-HPO2) - ) and phosphonate (-PO3) - ); R 1 R 2 R 3 R 4 R 5 and R 6 The group selected individually is from the group consisting of: hydrogen, =O, -OH, -SH, -NH2, and optionally substituted monovalent hydrocarbon groups having 1 to 30 carbon atoms, preferably R. 1 R 2 R 3 R 4 R 5 and R 6 Choose individually from the following groups: hydrogen, C1-C 20 Alkyl, C1-C 20 Haloalkyl, C1-C 20 Alkyl alcohols, C1-C 20 aminoalkyl, C2-C 20 alkenyl, C3-C8 cycloalkyl, C4-C8 cycloalkenyl, C6-C 10 Aryl, C1-C 20 Thioether, =O, -OH, -NH2, -SH, -OR 7 -NR 7 R 7’ -SR7 -(OCH2CH2) p CH3、-(OCHCH3CH2) q CH 3、 -(OCH3) r CH3, -R 7 OR 7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’ -R 7 (NHCONH)R 7’ -N=CR 7 R 7’ -N=CR 7’’ C(O)R 7 ;R 7 Choose from the following groups: C1-C 20 Alkyl, C1-C 20 Haloalkyl, C1-C 20 aminoalkyl, C2-C 20 alkenyl, C1-C 20 Alkyl alcohols, -(OCH2CH2) p CH3、-(OCHCH3CH2) q CH3、-(OCH3) r CH3, preferably R 7 Choose freely from C1 to C 20 The group consisting of alkyl groups; R 7’ Choose from the following groups: hydrogen, C1-C 20 Alkyl, C1-C 20 Haloalkyl, C1-C 20 aminoalkyl, C2-C 20 alkenyl, C1-C 20 Alkyl alcohols, -(OCH2CH2) p CH3、-(OCHCH3CH2) q CH3、-(OCH3) r CH3, preferably R 7’ Choose free hydrogen, C1-C 20 The group consisting of alkyl groups; R 7’’ It is a divalent C2-C8 alkyl group, such that -N=CR 7’’It is a cycloalkyl group; n, m, and o are each individually selected from 0 to 20, preferably 0 to 10 integers; in formulas (Ia) and (Ib), at least one of n, m, and o is > 0; p, q, and r are each individually selected from 1 to 30, preferably 2 to 20 integers; Z is selected from Z 1 Z 2 Z 3 Z 4 Z 5 Z 6 and Z 7 Any one of them, where Z 1 Z 2 Z 3 Z 4 Z 5 Z 6 and Z 7 as follows: R 8 R 9 and R 10 Individually selected from the group consisting of: hydrogen and optionally substituted monovalent hydrocarbon groups having 1 to 30 carbon atoms, preferably R 8 R 9 and R 10 Choose individually from the following groups: hydrogen, C1-C 20 Alkyl, C1-C 20 Haloalkyl, C1-C 20 Alkyl alcohols, C1-C 20 aminoalkyl, C1-C 20 sulfides, -R 7 OR 7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’ -R 7 (NHCONH)R 7’ -N=CR 7 R 7’ -N=CR 7’’ -C(O)R 7 More preferably R 8 R 9 and R 10Individually selected from the group consisting of: hydrogen, C1-C8 alkyl, C1-C8 haloalkyl, C1-C8 alkyl alcohol, C1-C8 aminoalkyl, C1-C8 sulfide, -R 7 OR 7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’ -R 7 (NHCONH)R 7’ -N=CR 7 R 7’ -N=CR 7’’ -C(O)R 7 ;R 11 R 12 R 13 R 14 and R 15 The group consisting solely of hydrogen and optionally substituted monovalent hydrocarbon groups having 1 to 30 carbon atoms, preferably R, is selected from the group consisting solely of hydrogen and optionally substituted monovalent hydrocarbon groups having 1 to 30 carbon atoms. 11 R 12 R 13 R 14 and R 15 Choose individually from the following groups: hydrogen, C1-C 20 Alkyl, C1-C 20 Haloalkyl, C1-C 20 Alkyl alcohols, C1-C 20 aminoalkyl, C2-C 20 alkenyl, C3-C8 cycloalkyl, C4-C8 cycloalkenyl, C6-C 10 Aryl, C1-C 20 sulfides, -R 7 OR 7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’ -R 7 (NHCONH)R 7’ -N=CR7 R 7’ -N=CR 7’’ -C(O)R 7 The electrical conductivity of the heat transfer fluid is less than 100 µS / cm, preferably less than 50 µS / cm, more preferably less than 25 µS / cm, even more preferably less than 10 µS / cm, and most preferably less than 5 µS / cm.

[0022] Very preferably, the heat transfer fluid contains a corrosion inhibitor, which is preferably selected from triazoles, thiazoles, triazines, diazoles, and combinations thereof.

[0023] In a preferred embodiment, the heat transfer fluid comprises a base liquid consisting of water, alcohol, or a mixture thereof.

[0024] In a preferred embodiment, the heat transfer fluid comprises at least 0.1 wt.%, preferably at least 0.01 wt.%, more preferably at least 0.05 wt.%, preferably at least 0.5 wt.%, more preferably at least 1 wt.% of an amphoteric compound according to formula (Ia) or (Ib) based on the total weight of the heat transfer fluid.

[0025] In a preferred embodiment, the zwitterionic compound of the heat transfer fluid is selected from zwitterionic compounds having a molecular weight of less than 1000 g / mol, preferably less than 500 g / mol, and preferably less than 200 g / mol.

[0026] In a preferred embodiment, a heat transfer fluid according to the invention is provided, wherein the weight ratio of the zwitterionic compound to the corrosion inhibitor (based on the total weight of the heat transfer fluid) is preferably at least 5:1, preferably at least 10:1, and more preferably at least 15:1.

[0027] In another aspect of the invention, a method for exchanging heat is provided, the method comprising the steps of: a. providing a heat transfer fluid according to the invention; b. providing a cooling system configured to thermally contact the heat transfer fluid with an electrical system, the cooling system comprising an ion exchange resin; c. transferring heat from the electrical system to the heat transfer fluid; and d. contacting the heat transfer fluid with the ion exchange resin.

[0028] In a preferred embodiment, the volume ratio of the heat transfer fluid to the ion exchange resin is at least 1:99 v / v%, preferably at least 5:95 v / v%, more preferably at least 10:90 v / v%, and most preferably at least 20:80 v / v.

[0029] In another aspect of the invention, the use of a heat transfer fluid comprising a zwitterionic compound according to formula (Ia) or (Ib) as a heat transfer fluid in a cooling system comprising an ion exchange resin is provided; wherein the heat transfer fluid has a conductivity at 25°C of less than 100 µS / cm, preferably less than 50 µS / cm, more preferably less than 25 µS / cm, more preferably less than 10 µS / cm, and most preferably less than 5 µS / cm.

[0030] In another aspect of the invention, the zwitterionic compounds according to formula (Ia) or (Ib) are provided for the following uses: • for prolonging the corrosion inhibition properties of a heat transfer fluid containing a corrosion inhibitor when in contact with an ion exchange resin, preferably when used as a heat transfer fluid in a cooling system containing an ion exchange resin in contact with the heat transfer fluid; • for prolonging the coloring of a heat transfer fluid containing a dye when in contact with an ion exchange resin, preferably when used as a heat transfer fluid in a cooling system containing an ion exchange resin in contact with the heat transfer fluid; • for reducing the corrosion inhibitors and / or... used in the heat transfer fluid when the heat transfer fluid contains the dye and when used as a heat transfer fluid in a cooling system containing an ion exchange resin in contact with the heat transfer fluid. The amount of dye; • For extending the service life of ion exchange resins by reducing or avoiding the uptake of heat transfer fluid components when in contact with a heat transfer fluid, preferably when the heat transfer fluid is used in a cooling system containing ion exchange resins in contact with the heat transfer fluid; • For extending the service life of heat transfer fluids containing corrosion inhibitors (and preferably alcohols as described herein) and / or ion exchange resins in contact with the heat transfer fluids by: ○ reducing, delaying or avoiding corrosion; ○ reducing, delaying or avoiding the formation of conductive acids such as glycolates; preferably when the heat transfer fluid is used in a cooling system containing ion exchange resins in contact with the heat transfer fluid. Detailed Implementation

[0031] The terms “comprise” and its variations, such as “comprises” and “comprising”, as used herein should be interpreted in an open and inclusive sense, meaning that the described embodiments include the listed features but do not exclude the presence of other features, provided that they do not render the embodiments infeasible.

[0032] As used herein, expressions such as "an embodiment," "specific embodiment," and "embodiment" should be interpreted as meaning that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment. Therefore, the appearance of such expressions throughout this specification does not necessarily refer to the same embodiment. Furthermore, in one or more embodiments, particular features, structures, or characteristics may be combined in any suitable manner. For example, certain features of this disclosure described herein in the context of individual embodiments are also explicitly contemplated for combination in a single embodiment.

[0033] Unless the context clearly specifies otherwise, the singular forms “a / an” and “the” as used herein should be interpreted to include the plural indicator. It should also be noted that, unless the context clearly specifies otherwise, the term “or” is generally used in its broadest sense, meaning “and / or”.

[0034] Unless otherwise explicitly defined, whenever a compound is referred to as a salt throughout this document, this should be interpreted to include the anhydrous form of the compound as well as any solvates (especially hydrates).

[0035] As used herein, the term "alkyl" includes straight-chain, branched, and cyclic alkyl groups.

[0036] The disclosure refers to substances, components, or ingredients that are present prior to their initial contact, blending, or mixing with one or more other substances, components, or ingredients according to this disclosure. A substance, component, or ingredient may acquire its identity, properties, or characteristics through chemical reactions or transformations during the process of contact, blending, or mixing (if carried out according to this disclosure using the common sense and ordinary skills of a common chemist). Unless otherwise expressly indicated, the definition of a substance, component, or ingredient and its relative amounts relates to the heat transfer fluid prepared when the components are first brought into contact.

[0037] As mentioned herein, the conductivity is preferably measured according to ASTM D1125-23, preferably using a Mettler-Toledo SevenExcellence Cond meter S700-Std-Kit conductivity meter equipped with a SevenExcellence Cond meter S700-Std-Kit.

[0038] The term 'thermal contact' refers to any arrangement that allows heat generated by an electrical system to be transferred via thermal transfer to a heat transfer fluid or a combination thereof. Heat transfer fluid

[0039] In a first aspect of the invention, a heat transfer fluid is provided, the heat transfer fluid comprising: at least one zwitterionic compound according to formula (Ia) or (Ib); Where Y is selected from sulfonate (-SO3) - ), phosphite (-HPO2) - ) and phosphonate (-PO3) - ); R 1 R 2 R 3 R 4 R 5 and R 6 The group selected individually is from the group consisting of: hydrogen, =O, -OH, -SH, -NH2, and optionally substituted monovalent hydrocarbon groups having 1 to 30 carbon atoms, preferably R. 1 R 2 R 3 R 4 R 5 and R 6 Choose individually from the following groups: hydrogen, C1-C 20 Alkyl, C1-C 20 Haloalkyl, C1-C 20 Alkyl alcohols, C1-C 20 aminoalkyl, C2-C 20 alkenyl, C3-C8 cycloalkyl, C4-C8 cycloalkenyl, C6-C 10 Aryl, C1-C 20 Thioether, =O, -OH, -NH2, -SH, -OR 7 -NR 7 R 7’ -SR 7 -(OCH2CH2) p CH3、-(OCHCH3CH2) q CH 3、 -(OCH3) r CH3, -R 7 OR 7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’ -R 7 (NHCONH)R 7’ -N=CR7 R 7’ -N=CR 7’’ C(O)R 7 ;R 7 Choose from the following groups: C1-C 20 Alkyl, C1-C 20 Haloalkyl, C1-C 20 aminoalkyl, C2-C 20 alkenyl, C1-C 20 Alkyl alcohols, -(OCH2CH2) p CH3、-(OCHCH3CH2) q CH3、-(OCH3) r CH3, preferably R 7 Choose freely from C1 to C 20 The group consisting of alkyl groups; R 7’ Choose from the following groups: hydrogen, C1-C 20 Alkyl, C1-C 20 Haloalkyl, C1-C 20 aminoalkyl, C2-C 20 alkenyl, C1-C 20 Alkyl alcohols, -(OCH2CH2) p CH3、-(OCHCH3CH2) q CH3、-(OCH3) r CH3, preferably R 7’ Choose free hydrogen, C1-C 20 The group consisting of alkyl groups; R 7’’ It is a divalent C2-C8 alkyl group, such that -N=CR 7’’ It is a cycloalkyl group; n, m, and o are each individually selected from 0 to 20, preferably 0 to 10 integers; in formulas (Ia) and (Ib), at least one of n, m, and o is > 0; p, q, and r are each individually selected from 1 to 30, preferably 2 to 20 integers; Z is selected from Z 1 Z 2 Z 3 Z 4 Z 5 Z 6 and Z 7 Any one of them, where Z 1 Z 2 Z 3 Z 4 Z 5 Z 6 and Z 7 as follows: Where R 8 R 9 and R10 Individually selected from the group consisting of: hydrogen and optionally substituted monovalent hydrocarbon groups having 1 to 30 carbon atoms, preferably R 8 R 9 and R 10 Choose individually from the following groups: hydrogen, C1-C 20 Alkyl, C1-C 20 Haloalkyl, C1-C 20 Alkyl alcohols, C1-C 20 aminoalkyl, C1-C 20 sulfides, -R 7 OR 7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’ -R 7 (NHCONH)R 7’ -N=CR 7 R 7’ -N=CR 7’’ -C(O)R 7 More preferably R 8 R 9 and R 10 Individually selected from the group consisting of: hydrogen, C1-C8 alkyl, C1-C8 haloalkyl, C1-C8 alkyl alcohol, C1-C8 aminoalkyl, C1-C8 sulfide, -R 7 OR 7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’ -R 7 (NHCONH)R 7’ -N=CR 7 R 7’ -N=CR 7’’ -C(O)R 7 ;R 11 R 12 R13 R 14 and R 15 The group consisting solely of hydrogen and optionally substituted monovalent hydrocarbon groups having 1 to 30 carbon atoms, preferably R, is selected from the group consisting solely of hydrogen and optionally substituted monovalent hydrocarbon groups having 1 to 30 carbon atoms. 11 R 12 R 13 R 14 and R 15 Choose individually from the following groups: hydrogen, C1-C 20 Alkyl, C1-C 20 Haloalkyl, C1-C 20 Alkyl alcohols, C1-C 20 aminoalkyl, C2-C 20 alkenyl, C3-C8 cycloalkyl, C4-C8 cycloalkenyl, C6-C 10 Aryl, C1-C 20 sulfides, -R 7 OR 7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’ -R 7 (NHCONH)R 7’ -N=CR 7 R 7’ -N=CR 7’’ -C(O)R 7 The electrical conductivity of the heat transfer fluid is less than 100 µS / cm, preferably less than 50 µS / cm, more preferably less than 25 µS / cm, even more preferably less than 10 µS / cm, and most preferably less than 5 µS / cm.

[0040] Very preferably, the heat transfer fluid contains a corrosion inhibitor, such as a corrosion inhibitor selected from triazoles, thiazoles, triazines, diazoles, and combinations thereof. Corrosion inhibitors are discussed in more detail elsewhere herein.

[0041] In a preferred embodiment of the invention, a heat transfer fluid comprising a base fluid is provided, wherein the base fluid is composed of water, or alcohol, or a mixture thereof.

[0042] In another embodiment of the invention, a heat transfer fluid is provided comprising a base fluid and an amphoteric compound according to formula (Ia) or (Ib); wherein the base fluid is composed of water, or an alcohol, or a mixture thereof; wherein the heat transfer fluid has a conductivity at 25°C of less than 100 µS / cm, preferably less than 50 µS / cm, more preferably less than 25 µS / cm, more preferably less than 10 µS / cm, and most preferably less than 5 µS / cm; and wherein the heat transfer fluid further comprises a corrosion inhibitor, preferably selected from triazoles, thiazoles, triazines, diazoles, and combinations thereof, and wherein the ratio (w / w) of the amphoteric compound to the corrosion inhibitor in the heat transfer fluid is less than 50:1, more preferably less than 30:1; and / or wherein the heat transfer fluid further comprises a dye, preferably a dye as described above, and wherein the ratio (w / w) of the amphoteric compound to the dye in the heat transfer fluid is at least 30:1, preferably at least 50:1.

[0043] The heat transfer fluid preferably has a pH in the range of 3-10, preferably 4-8, and more preferably 4-7.5. As those skilled in the art will understand, any compound having exchangeable hydrogen (due to its acid-base functionality) will be in equilibrium with its (de)protonated form. According to the invention, at least 50 mol%, preferably at least 80 mol%, and more preferably at least 99 mol% of the zwitterionic compound is in zwitterionic form at the pH of the heat transfer fluid. Typically, the zwitterionic compound is selected such that at least 99.9 mol%, or even 99.99 mol%, of the compound is in zwitterionic form at the pH of the heat transfer fluid. Therefore, preferably at least 50 mol%, preferably at least 80 mol%, and more preferably at least 99 mol% of the zwitterionic compound is in zwitterionic form at a pH in the range of 3-10, preferably 4-8, and more preferably 4-7.5. In some embodiments, at least 99.9 mol%, or even 99.99 mol%, of the zwitterionic compound is in zwitterionic form at a pH range of 3-10, preferably 4-8, more preferably 4-7.5.

[0044] In the context of this disclosure, and as is common in the art, the term “zwitterionic compound” refers to a neutral molecule containing equal numbers of positively and negatively charged groups.

[0045] According to the present invention, the zwitterionic compound is selected from the group consisting of compounds according to formula (Ia) or (Ib); Where Y is selected from sulfonate (-SO3) - ), phosphite (-HPO2) -) and phosphonate (-PO3) - ); R 1 R 2 R 3 R 4 R 5 and R 6 The group selected individually is from the group consisting of: hydrogen, =O, -OH, -SH, -NH2, and optionally substituted monovalent hydrocarbon groups having 1 to 30 carbon atoms, preferably R. 1 R 2 R 3 R 4 R 5 and R 6 Choose individually from the following groups: hydrogen, C1-C 20 Alkyl, C1-C 20 Haloalkyl, C1-C 20 Alkyl alcohols, C1-C 20 aminoalkyl, C2-C 20 alkenyl, C3-C8 cycloalkyl, C4-C8 cycloalkenyl, C6-C 10 Aryl, C1-C 20 Thioether, =O, -OH, -NH2, -SH, -OR 7 -NR 7 R 7’ -SR 7 -(OCH2CH2) p CH3、-(OCHCH3CH2) q CH 3、 -(OCH3) r CH3, -R 7 OR 7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’ -R 7 (NHCONH)R 7’ -N=CR 7 R 7’ -N=CR 7’’ C(O)R 7 ;R 7 Choose from the following groups: C1-C 20 Alkyl, C1-C 20 Haloalkyl, C1-C20 aminoalkyl, C2-C 20 alkenyl, C1-C 20 Alkyl alcohols, -(OCH2CH2) p CH3、-(OCHCH3CH2) q CH3、-(OCH3) r CH3, preferably R 7 Choose freely from C1 to C 20 The group consisting of alkyl groups, more preferably R 7 Choose freely from C1 to C 14 The group consisting of alkyl groups; R 7’ Choose from the following groups: hydrogen, C1-C 20 Alkyl, C1-C 20 Haloalkyl, C1-C 20 aminoalkyl, C2-C 20 alkenyl, C1-C 20 Alkyl alcohols, -(OCH2CH2) p CH3、-(OCHCH3CH2) q CH3、-(OCH3) r CH3, preferably R 7’ Choose free hydrogen, C1-C 20 The group consisting of alkyl groups, more preferably R 7’ Choose freely from C1 to C 14 The group consisting of alkyl groups; R 7’’ It is a divalent C2-C8 alkyl group, such that -N=CR 7’’ It is a cycloalkyl group; n, m, and o are each individually selected from 0 to 20, preferably 0 to 10; in formulas (Ia) and (Ib), at least one of n, m, and o is > 0; p, q, and r are each individually selected from 1 to 30, preferably 2 to 20 integers; Z is selected from Z 1 Z 2 Z 3 Z 4 Z 5 Z 6 Z 7 Z 8 and Z 9 Any one of them, where Z 1 Z 2 Z 3 Z 4 Z 5 Z 6 Z 7 Z 8 and Z 9 as follows: R 8 R9 and R 10 Individually selected from the group consisting of: hydrogen and optionally substituted monovalent hydrocarbon groups having 1 to 30 carbon atoms, preferably R 8 R 9 and R 10 Choose individually from the following groups: hydrogen, C1-C 20 Alkyl, C1-C 20 Haloalkyl, C1-C 20 Alkyl alcohols, C1-C 20 aminoalkyl, C1-C 20 sulfides, -R 7 OR 7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’ -R 7 (NHCONH)R 7’ -N=CR 7 R 7’ -N=CR 7’’ -C(O)R 7 More preferably R 8 R 9 and R 10 Individually selected from the group consisting of: hydrogen, C1-C8 alkyl, C1-C8 haloalkyl, C1-C8 alkyl alcohol, C1-C8 aminoalkyl, C1-C8 sulfide, -R 7 OR 7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’ -R 7 (NHCONH)R 7’ -N=CR 7 R 7’ -N=CR 7’’ -C(O)R 7 ;R 11 R12 R 13 R 14 and R 15 The group consisting solely of hydrogen and optionally substituted monovalent hydrocarbon groups having 1 to 30 carbon atoms, preferably R, is selected from the group consisting solely of hydrogen and optionally substituted monovalent hydrocarbon groups having 1 to 30 carbon atoms. 11 R 12 R 13 R 14 and R 15 Choose individually from the following groups: hydrogen, C1-C 20 Alkyl, C1-C 20 Haloalkyl, C1-C 20 Alkyl alcohols, C1-C 20 aminoalkyl, C2-C 20 alkenyl, C3-C8 cycloalkyl, C4-C8 cycloalkenyl, C6-C 10 Aryl, C1-C 20 sulfides, -R 7 OR 7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’ -R 7 (NHCONH)R 7’ -N=CR 7 R 7’ -N=CR 7’’ -C(O)R 7 .

[0046] In a preferred embodiment of the invention, the zwitterionic compound is selected from the group consisting of compounds according to formula (Ia) and compounds according to formula (Ib), wherein Y is selected from sulfonate (-SO3) - ), phosphite (-HPO2) - ) and phosphonate (-PO3) - ); R 1 R 3 and R 5 The group selected individually is from the group consisting of: hydrogen, =O, -OH, -SH, -NH2, and optionally substituted monovalent hydrocarbon groups having 1 to 30 carbon atoms, preferably R. 1 R 3 and R 5 Choose individually from the following groups: hydrogen, C1-C 20Alkyl, C1-C 20 Haloalkyl, C1-C 20 Alkyl alcohols, C1-C 20 aminoalkyl, C2-C 20 alkenyl, C3-C8 cycloalkyl, C4-C8 cycloalkenyl, C6-C 10 Aryl, C1-C 20 Thioether, =O, -OH, -NH2, -SH, -OR 7 -NR 7 R 7’ -SR 7 -(OCH2CH2) p CH3、-(OCHCH3CH2) q CH 3、 -(OCH3) r CH3, -R 7 OR 7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’ -R 7 (NHCONH)R 7’ -N=CR 7 R 7’ -N=CR 7’’ -C(O)R 7 ;R 2 R 4 and R 6 It is hydrogen; R 7 Choose from the following groups: C1-C 20 Alkyl, C1-C 20 Haloalkyl, C1-C 20 aminoalkyl, C2-C 20 alkenyl, C1-C 20 Alkyl alcohols, -(OCH2CH2) p CH3、-(OCHCH3CH2) q CH3、-(OCH3) r CH3, preferably R 7 Choose freely from C1 to C 20 The group consisting of alkyl groups, more preferably R 7 Choose freely from C1 to C 14 The group consisting of alkyl groups; R 7’Choose from the following groups: hydrogen, C1-C 20 Alkyl, C1-C 20 Haloalkyl, C1-C 20 aminoalkyl, C2-C 20 alkenyl, C1-C 20 Alkyl alcohols, -(OCH2CH2) p CH3、-(OCHCH3CH2) q CH3、-(OCH3) r CH3, preferably R 7’ Choose free hydrogen, C1-C 20 The group consisting of alkyl groups, more preferably R 7’ Choose freely from C1 to C 14 The group consisting of alkyl groups; R 7’’ It is a divalent C2-C8 alkyl group, such that -N=CR 7’’ It is a cycloalkyl group; n, m, and o are each individually selected from 0 to 20, preferably 0 to 10; in formulas (Ia) and (Ib), at least one of n, m, and o is > 0; p, q, and r are each individually selected from 1 to 30, preferably 2 to 20 integers; Z is selected from Z 1 Z 2 Z 3 Z 4 Z 5 Z 6 Z 7 Z 8 and Z 9 Any one of them, where Z 1 Z 2 Z 3 Z 4 Z 5 Z 6 Z 7 Z 8 and Z 9 as follows: R 8 R 9 and R 10 Individually selected from the group consisting of: hydrogen and optionally substituted monovalent hydrocarbon groups having 1 to 30 carbon atoms, preferably R 8 R 9 and R 10 Choose individually from the following groups: hydrogen, C1-C 20 Alkyl, C1-C 20 Haloalkyl, C1-C 20 Alkyl alcohols, C1-C 20 aminoalkyl, C1-C 20 sulfides, -R 7 OR7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’ -R 7 (NHCONH)R 7’ -N=CR 7 R 7’ -N=CR 7’’ -C(O)R 7 More preferably R 8 R 9 and R 10 Individually selected from the group consisting of: hydrogen, C1-C8 alkyl, C1-C8 haloalkyl, C1-C8 alkyl alcohol, C1-C8 aminoalkyl, C1-C8 sulfide, -R 7 OR 7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’ -R 7 (NHCONH)R 7’ -C(O)R 7 ;R 11 R 12 R 13 R 14 and R 15 Individually selected from the group consisting of: hydrogen and optionally substituted monovalent hydrocarbon groups having 1 to 30 carbon atoms, preferably R 11 R 12 R 13 R 14 and R 15 Choose individually from the following groups: hydrogen, C1-C 20 Alkyl, C1-C 20 Haloalkyl, C1-C 20 Alkyl alcohols, C1-C 20 aminoalkyl, C2-C 20alkenyl, C3-C8 cycloalkyl, C4-C8 cycloalkenyl, C6-C 10 Aryl, C1-C 20 sulfides, -R 7 OR 7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’ -R 7 (NHCONH)R 7’ -N=CR 7 R 7’ -N=CR 7’’ -C(O)R 7 More preferably R 11 R 12 R 13 R 14 and R 15 Individually selected from the group consisting of: hydrogen, C1-C8 alkyl, C1-C8 haloalkyl, C1-C8 alkyl alcohol, C1-C8 aminoalkyl, C1-C8 sulfide, -R 7 OR 7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’ -R 7 (NHCONH)R 7’ -C(O)R 7 .

[0047] In a very preferred embodiment of the invention, the zwitterionic compound is selected from the group consisting of compounds according to formula (Ia) and compounds according to formula (Ib), wherein Y is selected from sulfonate (-SO3) - ), phosphite (-HPO2) - ) and phosphonate (-PO3) - ); R 1 R 2 R 3 R4 R 5 and R 6 Individually selected from the group consisting of: hydrogen, -OH, -SH, -NH2, C1-C8 alkyl, C1-C8 haloalkyl, C1-C8 alkyl alcohol, C1-C8 aminoalkyl, C1-C8 sulfide, preferably R 1 R 3 and R 5 Individually selected from the group consisting of: hydrogen, -OH, -SH, -NH2, C1-C8 alkyl, most preferably R 1 R 3 and R 5 Individually selected from the group consisting of: hydrogen, -OH, C1-C5 alkyl; n, m, and o are each individually selected from 0 to 20, preferably 0 to 10, more preferably 0 to 2; in formulas (Ia) and (Ib), at least one of n, m, and o is > 0; Z is selected from Z 1 Z 2 Z 3 Z 4 Z 5 Z 6 Z 7 Z 8 and Z 9 Any one of them, where Z 1 Z 2 Z 3 Z 4 Z 5 Z 6 Z 7 Z 8 and Z 9 as follows: R 8 R 9 and R 10 Individually selected from the group consisting of: hydrogen, C1-C8 alkyl, C1-C8 haloalkyl, C1-C8 alkyl alcohol, C1-C8 aminoalkyl, C1-C8 sulfide, -R 7 OR 7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’、 -R 7 (NHCONH)R 7’-C(O)R 7 Preferably R 8 R 9 and R 10 Individually selected from the group consisting of: C1-C8 alkyl, C1-C8 haloalkyl, C1-C8 alkyl alcohol, C1-C8 aminoalkyl, C1-C8 sulfide, -R 7 OR 7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’ -R 7 (NHCONH)R 7’ -C(O)R 7 More preferably R 8 R 9 and R 10 Individually selected from the group consisting of: C1-C4 alkyl, -R 7 OR 7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’ -R 7 (NHCONH)R 7’ -C(O)R 7 ;R 11 R 12 R 13 R 14 and R 15 Choose individually from the following groups: hydrogen, C1-C 20 Alkyl, C1-C 20 Haloalkyl, C1-C 20 Alkyl alcohols, C1-C 20 aminoalkyl, C2-C 20 alkenyl, C3-C8 cycloalkyl, C4-C8 cycloalkenyl, C6-C 10 Aryl, C1-C 20 sulfides, -R 7 OR7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’ -R 7 (NHCONH)R 7’ -C(O)R 7 ;R 7 Choose from the following groups: C1-C 20 Alkyl, C1-C 20 Haloalkyl, C1-C 20 aminoalkyl, C2-C 20 alkenyl, C1-C 20 Alkyl alcohols, -(OCH2CH2) p CH3、-(OCHCH3CH2) q CH3、-(OCH3) r CH3, preferably R 7 Choose freely from C1 to C 20 The group consisting of alkyl groups, more preferably R 7 Choose freely from C1 to C 14 The group consisting of alkyl groups; R 7’ Choose from the following groups: hydrogen, C1-C 20 Alkyl, C1-C 20 Haloalkyl, C1-C 20 aminoalkyl, C2-C 20 alkenyl, C1-C 20 Alkyl alcohols, -(OCH2CH2) p CH3、-(OCHCH3CH2) q CH3、-(OCH3) r CH3, preferably R 7’ Choose free hydrogen, C1-C 20 The group consisting of alkyl groups, more preferably R 7’ Choose freely from C1 to C 14 A group composed of alkyl groups.

[0048] In a very preferred embodiment of the invention, the zwitterionic compound is selected from the group consisting of compounds according to formula (Ia) and compounds according to formula (Ib), wherein Y is selected from sulfonate (-SO3) - ), phosphite (-HPO2) - ) and phosphonate (-PO3)- ); R 1 R 3 and R 5 Individually selected from the group consisting of: hydrogen, -OH, -SH, -NH2, C1-C8 alkyl, C1-C8 haloalkyl, C1-C8 alkyl alcohol, C1-C8 aminoalkyl, C1-C8 sulfide, preferably R 1 R 3 and R 5 Individually selected from the group consisting of: hydrogen, -OH, -SH, -NH2, C1-C8 alkyl, most preferably R 1 R 3 and R 5 Individually selected from the group consisting of: hydrogen, -OH, C1-C5 alkyl; R 2 R 4 and R 6 It is hydrogen; n, m, and o are each individually selected from 0 to 20, preferably 0 to 10, more preferably 0 to 2; in formulas (Ia) and (Ib), at least one of n, m, and o is > 0; Z is selected from Z 1 Z 2 Z 3 Z 4 Z 5 Z 6 Z 7 Z 8 and Z 9 Any one of them, where Z 1 Z 2 Z 3 Z 4 Z 5 Z 6 Z 7 Z 8 and Z 9 as follows: R 8 R 9 and R 10 Individually selected from the group consisting of: hydrogen, C1-C8 alkyl, C1-C8 haloalkyl, C1-C8 alkyl alcohol, C1-C8 aminoalkyl, C1-C8 sulfide, -R 7 OR 7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7(NHCOO)R 7’ -R 7 (NHCONH)R 7’ -C(O)R 7 Preferably R 8 R 9 and R 10 Individually selected from the group consisting of: C1-C8 alkyl, C1-C8 haloalkyl, C1-C8 alkyl alcohol, C1-C8 aminoalkyl, C1-C8 sulfide, -R 7 OR 7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’ -R 7 (NHCONH)R 7’ -C(O)R 7 More preferably R 8 R 9 and R 10 Individually selected from the group consisting of: C1-C4 alkyl, -R 7 OR 7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’ -R 7 (NHCONH)R 7’ -C(O)R 7 ;R 11 R 12 R 13 R 14 and R 15 Choose individually from the following groups: hydrogen, C1-C 20 Alkyl, C1-C 20 Haloalkyl, C1-C 20 Alkyl alcohols, C1-C 20 aminoalkyl, C2-C 20alkenyl, C3-C8 cycloalkyl, C4-C8 cycloalkenyl, C6-C 10 Aryl, C1-C 20 sulfides, -R 7 OR 7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’ -R 7 (NHCONH)R 7’ -C(O)R 7 ;R 7 Choose from the following groups: C1-C 20 Alkyl, C1-C 20 Haloalkyl, C1-C 20 aminoalkyl, C2-C 20 alkenyl, C1-C 20 Alkyl alcohols, -(OCH2CH2) p CH3、-(OCHCH3CH2) q CH3、-(OCH3) r CH3, preferably R 7 Choose freely from C1 to C 20 The group consisting of alkyl groups, more preferably R 7 Choose freely from C1 to C 14 The group consisting of alkyl groups; R 7’ Choose from the following groups: hydrogen, C1-C 20 Alkyl, C1-C 20 Haloalkyl, C1-C 20 aminoalkyl, C2-C 20 alkenyl, C1-C 20 Alkyl alcohols, -(OCH2CH2) p CH3、-(OCHCH3CH2) q CH3、-(OCH3) r CH3, preferably R 7’ Choose free hydrogen, C1-C 20 The group consisting of alkyl groups, more preferably R 7’ Choose freely from C1 to C 14 A group composed of alkyl groups.

[0049] In a very preferred embodiment of the invention, the zwitterionic compound is selected from the group consisting of compounds according to formula (Ia) and compounds according to formula (Ib), wherein Y is selected from sulfonate (-SO3) - ), phosphite (-HPO2) - ) and phosphonate (-PO3) - ); R 1 R 3 and R 5 Individually selected from the group consisting of: hydrogen, -OH, -SH, -NH2, C1-C6 alkyl, C1-C6 haloalkyl, C1-C6 alkyl alcohol, C1-C6 aminoalkyl, C1-C6 sulfide, preferably R 1 R 3 and R 5 Individually selected from the group consisting of: hydrogen, -OH, -SH, -NH2, C1-C6 alkyl, most preferably R 1 R 3 and R 5 Individually selected from the group consisting of: hydrogen, -OH, C1-C4 alkyl; R 2 R 4 and R 6 It is hydrogen; n, m, and o are each individually selected from 0 to 20, preferably 0 to 10, more preferably 0 to 2; in formulas (Ia) and (Ib), at least one of n, m, and o is > 0; Z is selected from Z 1 Z 2 Z 3 Z 4 Z 5 Z 6 Z 7 Z 8 and Z 9 Any one of them, where Z 1 Z 2 Z 3 Z 4 Z 5 Z 6 Z 7 Z 8 and Z 9 as follows: R 8 R 9 and R 10 Individually selected from the group consisting of: hydrogen, C1-C6 alkyl, C1-C6 haloalkyl, C1-C6 alkyl alcohol, C1-C6 aminoalkyl, C1-C6 sulfide, -R 7 OR 7’ -R 7 (CO)R 7’-R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’ -R 7 (NHCONH)R 7’ -C(O)R 7 Preferably R 8 R 9 and R 10 Individually selected from the group consisting of: C1-C5 alkyl, C1-C5 haloalkyl, C1-C5 alkyl alcohol, C1-C5 aminoalkyl, C1-C5 sulfide, -R 7 OR 7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’ -R 7 (NHCONH)R 7’ -C(O)R 7 More preferably R 8 R 9 and R 10 Individually selected from the group consisting of: C1-C4 alkyl, -R 7 OR 7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’ -R 7 (NHCONH)R 7’ -C(O)R 7 ;R 11 R 12 R 13 R 14 and R 15Choose individually from the following groups: hydrogen, C1-C 10 Alkyl, C1-C 10 Haloalkyl, C1-C 10 Alkyl alcohols, C1-C 10 aminoalkyl, C2-C 10 alkenyl, C3-C6 cycloalkyl, C4-C6 cycloalkenyl, C6-C8 aryl, C1-C 10 sulfides, -R 7 OR 7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’ -R 7 (NHCONH)R 7’ -C(O)R 7 ;R 7 Choose from the following groups: C1-C 10 Alkyl, C1-C 10 Haloalkyl, C1-C 10 aminoalkyl, C2-C 10 alkenyl, C1-C 10 Alkyl alcohols, -(OCH2CH2) p CH3、-(OCHCH3CH2) q CH3、-(OCH3) r CH3, preferably R 7 Choose freely from C1 to C 10 The group consisting of alkyl groups, more preferably R 7 Selected from the group consisting of C1-C8 alkyl groups; R 7’ Choose from the following groups: hydrogen, C1-C 10 Alkyl, C1-C 10 Haloalkyl, C1-C 10 aminoalkyl, C2-C 10 alkenyl, C1-C 10 Alkyl alcohols, -(OCH2CH2) p CH3、-(OCHCH3CH2) q CH3、-(OCH3) r CH3, preferably R 7’ Choose free hydrogen, C1-C 10 The group consisting of alkyl groups, more preferably R 7’Select from the group consisting of C1-C8 alkyl groups.

[0050] In preferred embodiments, for reasons of solubility and resin compatibility, the zwitterionic compound is preferably having a molecular weight of less than 1000 g / mol, preferably less than 500 g / mol, and more preferably less than 200 g / mol. Some zwitterionic compounds have been found to be particularly useful, for example, because they are particularly suitable for protecting corrosion inhibitors (such as triazoles), or because they are particularly suitable for protecting dyes. Therefore, preferred zwitterionic compounds will be described in more detail in the following paragraphs.

[0051] In a preferred embodiment of the invention, the zwitterionic compound does not include polymers. In some embodiments of the invention, the zwitterionic compound does not include trimethylglycine. In some embodiments of the invention, the heat transfer fluid does not contain trimethylglycine.

[0052] In some embodiments of the invention, the zwitterionic compound is selected from compounds containing a positive charge from a quaternary ammonium, sulfonium, or phosphonium functional group and a negative charge from a sulfonate, phosphonium, or phosphonate functional group in the same molecule. In a very preferred embodiment, the zwitterionic compound is selected from compounds containing a positive charge from a quaternary ammonium, sulfonium, or phosphonium functional group and a negative charge from a sulfonate functional group in the same molecule. In other embodiments, the zwitterionic compound is selected from compounds containing a positive charge from a quaternary ammonium functional group, preferably trimethylammonium, and a negative charge from a sulfonate, phosphonium, or phosphonate functional group in the same molecule.

[0053] In a preferred embodiment, the zwitterionic compound is selected from the group consisting of 2-aminoethanesulfonic acid (taurine), 4-tert-butyl-1-(3-sulfopropyl)pyridinium hydroxide, and combinations thereof.

[0054] This article describes R 1 -R 15 Preferred embodiments of n, m, and o are explicitly conceived as combinations.

[0055] In a very preferred embodiment of the invention, the zwitterionic compound exhibits a solubility of at least 1 g / L, preferably at least 5 g / L, and most preferably at least 10 g / L in a base solution consisting of 50 vol% monoethylene glycol in water.

[0056] In a preferred embodiment of the invention, the concentration of the zwitterionic compound in the heat transfer fluid is at least 0.05 wt.%, preferably at least 0.1 wt.%, more preferably at least 0.5 wt.%, and most preferably at least 1 wt.%, based on the total weight of the heat transfer fluid. The zwitterionic compound is typically contained in the heat transfer fluid at a concentration of less than 10 wt.%, preferably less than 6 wt.%, more preferably less than 4 wt.%, and most preferably less than 3 wt.%, based on the total weight of the heat transfer fluid. In embodiments of the invention, particularly those in which the zwitterionic compound is selected from compounds as defined elsewhere herein, the total amount of the zwitterionic compound in the heat transfer fluid is in the range of 0.05-10 wt.%, preferably in the range of 0.1-6 wt.%, more preferably in the range of 0.5-4 wt.%, and most preferably in the range of 1-3 wt.%.

[0057] In some embodiments, the heat transfer fluid comprises a single zwitterionic compound as described herein. Base fluid

[0058] According to the present invention, the base fluid contained in the heat transfer fluid is composed of water, or an alcohol, or a mixture thereof. In a preferred embodiment of the invention, the alcohol is selected from the group consisting of: monoethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, hexaethylene glycol, monopropylene glycol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, pentapropylene glycol, hexapropylene glycol, methanol, ethanol, propanol, butanol, tetrahydrofurfuryl alcohol, ethoxylated furfuryl alcohol, dimethyl ether of glycerol, sorbitol, 1,2,6-hexanetriol, trimethylolpropane, methoxyethanol, glycerol, and mixtures thereof, preferably selected from the group consisting of: monoethylene glycol, monopropylene glycol, 1,3-propanediol, glycerol, and mixtures thereof.

[0059] In a preferred embodiment of the invention, the base liquid comprises an alcohol, preferably an alcohol as described herein, and the total amount of zwitterionic compound to alcohol is in a weight ratio between 1:250 and 1:2, between 1:100 and 1:2, preferably between 1:80 and 1:10, preferably between 1:50 and 1:20, and most preferably between 1:40 and 1:30.

[0060] In some embodiments of the invention, the base liquid comprises an alcohol, preferably an alcohol as described herein, and the total amount of zwitterionic compound to alcohol is in a weight ratio of 1:1000 to 1:100, preferably between 1:750 and 1:300, and more preferably between 1:600 ​​and 1:300.

[0061] As used in this article, “monoethylene glycol” should be interpreted as “ethane-1,2-diol” and is interchangeable with “MEG”.

[0062] As used in this article, “monopropylene glycol” should be interpreted as “propane-1,2-diol” and is interchangeable with “MPG”.

[0063] As used herein, the term "glycerol" means "propane-1,2,3-triol" and is synonymous with glycerol. In a preferred embodiment of the invention, the base liquid comprises water, ethylene glycol, propylene glycol, 1,3-propanediol, glycerol, or a mixture thereof.

[0064] In a preferred embodiment of the invention, the base liquid is composed of water and alcohol, wherein the alcohol is present in an amount of 10-99.5 wt.% (by weight of the base liquid), preferably 10-80 wt.%, more preferably 30-70 wt.%. In a specific embodiment, the alcohol is present in an amount in the range of 33-60 wt.% (by weight of the base liquid).

[0065] In some embodiments of the present invention, the base liquid consists of only water, that is, 100% of the base liquid is water.

[0066] In embodiments of the present invention, the base liquid contains more than 50 wt.%, preferably more than 70 wt.%, more preferably more than 85 wt.% water (by weight of the base liquid).

[0067] In embodiments of the present invention, the base liquid contains more than 50 wt.% of monoethylene glycol (by weight of the base liquid), preferably more than 70 wt.%, more preferably more than 85 wt.%, and most preferably more than 95 wt.% of monoethylene glycol.

[0068] In embodiments of the present invention, the base liquid contains more than 50 wt.% of monopropylene glycol (by weight of the base liquid), preferably more than 70 wt.%, more preferably more than 85 wt.%, and most preferably more than 95 wt.% of monopropylene glycol.

[0069] In embodiments of the present invention, the base liquid contains more than 50 wt.% of 1,3-propanediol (by weight of the base liquid), preferably more than 70 wt.%, more preferably more than 85 wt.%, and most preferably more than 95 wt.% of 1,3-propanediol.

[0070] In embodiments of the present invention, the base liquid contains more than 50 wt.% glycerol (by weight of the base liquid), preferably more than 70 wt.%, more preferably more than 85 wt.%, and most preferably more than 95 wt.% glycerol.

[0071] In a preferred embodiment of the invention, the heat transfer fluid comprises more than 78 wt.% (by total weight of the heat transfer fluid) of base fluid, more preferably more than 85 wt.%, even more preferably more than 90 wt.%, and still more preferably more than 95 wt.% or more than 96.5 wt.% of base fluid.

[0072] As those skilled in the art will understand, the base fluid is typically added to the heat transfer fluid in a 'sufficient amount'. In embodiments of the invention, the heat transfer fluid contains less than 99.9 wt.% of the base fluid (by total weight of the heat transfer fluid), such as less than 99.8 wt.%, less than 99.5 wt.%, or less than 99 wt.% or less than 98 wt.% of the base fluid.

[0073] In some embodiments of the invention, a base fluid is provided in which water and alcohol are present in a weight ratio of 95:5 to 5:95 based on the total weight of the heat transfer fluid. In other embodiments, a base fluid is provided in which water and alcohol are present in a weight ratio of 95:5 to 5:95 based on the total weight of the base fluid. Corrosion inhibitor

[0074] Cooling systems are typically configured to bring heat transfer fluids into thermal contact with easily corroded metal components. Illustrative metals include ferrous and nonferrous alloys such as stainless steel, aluminum, brass, brazing alloys, etc. The inventors of this invention have discovered that ion exchange resins (used in cooling systems of electrical systems to maintain the low conductivity of the coolant) readily remove corrosion inhibitors, even non-electrolyte corrosion inhibitors. This invention protects corrosion inhibitors that may be contained in the heat transfer fluid from absorption by the ion exchange resin, and thus allows the heat transfer fluid to retain the benefits obtained from the use of corrosion inhibitors.

[0075] In a preferred embodiment, the heat transfer fluid contains a corrosion inhibitor. The corrosion inhibitor is preferably a nonionic corrosion inhibitor. Examples of suitable nonionic corrosion inhibitors are triazoles, thiazoles, triazines, diazoles, nonionic polymers, silicates (such as Si(OR)4, where R is a C1 to C4 alkyl group), and organosilicon esters (such as Si(R)4). 1 ) n (OR 2 ) 4-n , where R 1 and R 2Each of the following is independently a C1 to C6 alkyl or phenyl group, wherein n is 0, 1, 2 or 3; a molecule containing trimethylsilyl group (such as N,O-bis(trimethylsilyl)acetamide, N-trimethylsilylacetamide); an alcohol containing an olefin or alkyne group (such as 3-buten-1-ol, 4-penten-1-ol, 2,5-dimethyl-3-hexyn-2,5-diol); and combinations thereof, wherein the nonionic polymer is preferably selected from the group consisting of: polyvinylpyrrolidone, polyvinyl alcohol, polyepoxide, polysiloxane, C1-C6 polyepoxide. 18 C1-C of alkyl or alkenyl ethers and polyepoxides 18 Alkyl or alkenyl esters, alkoxylated C1-C 18 Alkyl or alkenylamines, polyvinyl acetate, copolymers thereof, and combinations thereof.

[0076] The corrosion inhibitor is preferably selected from triazole, thiazole, triazine, diazole and combinations thereof.

[0077] In a preferred embodiment of the present invention, the corrosion inhibitor is selected from 1,2,3-triazole, 1,2,4-triazole and combinations thereof.

[0078] In a preferred embodiment of the present invention, the corrosion inhibitor is selected from 1,2,4-triazole, 4H-1,2,4-triazole, 4-amino-1,2,4-triazole, 3-amino-1,2,4-triazole, 1,2,4-triazole-3-thiol, 3-amino-1,2,4-triazole-5-thiol, 3,5-diamino-1,2,4-triazole, 1H-1,2,3-triazole, benzotriazole, 2-mercaptobenzothiazole, toluenetriazole, 2-[2-hydroxyethyl-[ (4-Methylbenzotriazol-1-yl)methyl]amino]ethanol, 2-[2-hydroxyethyl-[(benzotriazolyl)methyl]amino]ethanol, (2-benzothiazolylthio)acetic acid, 2,2'-[[(methyl-1H-benzotriazol-1-yl)methyl]imino]diethanol, N,N-bis(2-ethylhexyl)-methyl-1H-benzotriazol-1-methylamine and combinations thereof, more preferably selected from benzotriazole, tolyltriazole, 2-mercaptobenzothiazol and combinations thereof.

[0079] In some embodiments of the present invention, the corrosion inhibitor is a thiazole selected from the following: 4,4'-(4(ethane-1,2-diylbis(oxy))bis(4-phenylene)dithiazol-2-amine, 2-(acetyl-ethoxycarbonyl-methylene (methyleno))-3-phenyl-4-(phenylhydrazone)-1,3-thiazolidin-5-one, 2-amino-4-(4-chlorophenyl)-thiazole, 2-methoxy-1,3- Thiazoles, 4-(4-methylphenyl)-2-thiazolamine, 2-amino-4-methyl-thiazol, 2-salinylamino-4-phenylthiazol, 4-[1-aza-2-(phenyl)vinyl]-3-phenyl-2-thio(1,3-thiazolin-5-yl), 4-(4-methylphenyl)-2-thiazolamine, 2-amino-4-methyl-thiazol, 2-amino-thiazol, 2,2'-bis(benzothiazol) disulfide, and combinations thereof.

[0080] In some embodiments of the present invention, the corrosion inhibitor is selected from the following triazines: 1,2,3-triazine, 1,2,4-triazine, 1,3,5-triazine, 6-methyl-5-[m-nitrostyryl]-3-mercapto-1,2,4-triazine, 2,4,6-tris(2-pyridyll)-1,3,5-triazine and combinations thereof.

[0081] In some embodiments of the present invention, the corrosion inhibitor is selected from the following diazoles: pyrazole, 4-nitropyrazole, 4-sulfopyrazole.

[0082] In a preferred embodiment of the invention, the first corrosion inhibitor is selected from compounds according to general formulas (II-a), (II-b), and / or (II-c): Where R 1 This indicates one, two, or three substituents on a six-membered ring, each substituent independently selected from C1-C2. 11 Alkyl, amine, methoxy, ethoxy, Cl, or Br; wherein X is selected from nitrogen or CH groups; and wherein R 2 Selected from hydrogen, mercapto (-SH), or C1-C 11 Alkyl, preferably methyl or ethyl; preferably wherein R 1 This indicates one, two, or three substituents on a six-membered ring, each substituent independently selected from C1-C6 alkyl, amine, methoxy, ethoxy, Cl, or Br; wherein X is selected from a nitrogen or CH group; and wherein R 2 It is selected from hydrogen, mercapto (-SH) or C1-C6 alkyl, preferably methyl or ethyl.

[0083] In a preferred embodiment of the invention, the corrosion inhibitor is present in the heat transfer fluid in an amount of at least 0.005 wt.% (based on the total weight of the heat transfer fluid), preferably at least 0.01 wt.%, more preferably at least 0.05 wt.%. The corrosion inhibitor is typically present in an amount ranging from 0.005 to 5 wt.% (based on the total weight of the heat transfer fluid), preferably 0.01 to 3 wt.%, more preferably 0.05 to 1 wt.%. The ratio (w / w) of the zwitterionic compound to the corrosion inhibitor in the heat transfer fluid is preferably at least 5:1, preferably at least 10:1, more preferably at least 15:1. The ratio (w / w) of the zwitterionic compound to the corrosion inhibitor in the heat transfer fluid is preferably less than 50:1, preferably less than 49:1, preferably less than 48:1, preferably less than 45:1, preferably less than 35:1, more preferably less than 30:1.

[0084] In a preferred embodiment of the invention, a method is provided in which the heat transfer fluid comprises a corrosion inhibitor as described herein, and wherein the binding affinity of the corrosion inhibitor to the ion exchange resin is less than the binding affinity of the zwitterionic compound to the ion exchange resin. Preferably, a method is provided in which the heat transfer fluid comprises a corrosion inhibitor as described herein, and wherein the binding affinity of the corrosion inhibitor to the ion exchange resin is less than the binding affinity of the zwitterionic compound to the ion exchange resin, and wherein the binding affinity of the zwitterionic compound to the ion exchange resin is less than the binding affinity of the glycolate to the ion exchange resin.

[0085] To determine whether the binding affinity of a corrosion inhibitor to an ion exchange resin is less than that of a zwitterionic compound to the ion exchange resin, the following procedure can be used: - Prepare a mixture of 50 ml water, 50 ml monoethylene glycol, 2 ml ion exchange resin, 2 g of zwitterionic compound, and 0.1 g of corrosion inhibitor; - Determine the concentration of the corrosion inhibitor by an appropriate method (e.g., HPLC coupled with a UV-VIS detector); - Stir at 20°C for 3 hours; and - Determine the concentration of the corrosion inhibitor by the same method, wherein if the loss of corrosion inhibitor concentration after stirring is less than 50%, preferably less than 35%, then the binding affinity of the corrosion inhibitor to the ion exchange resin is determined to be less than that of the zwitterionic compound to the ion exchange resin.

[0086] To determine whether the binding affinity of the zwitterionic compound to the ion exchange resin is less than that of glycolate to the ion exchange resin, the following procedure can be used: - Prepare a mixture of 50 ml water, 50 ml monoethylene glycol, 2 ml ion exchange resin, 2 g of the zwitterionic compound, and 0.01 g of glycolic acid; - Determine the total combined concentration of glycolic acid and glycolate by an appropriate method (e.g., ion chromatography); - Stir at 20°C for 3 hours; and - Determine the total combined concentration of glycolic acid and glycolate by the same method, wherein if the loss of glycolate concentration after stirring exceeds 50%, preferably exceeds 80%, then the binding affinity of the zwitterionic compound to the ion exchange resin is determined to be less than that of glycolate to the ion exchange resin. Those skilled in the art will understand that ion chromatography measures only glycolate ions, but with appropriate sample preparation (addition of a strong base), all glycolic acid present in the sample can be converted to glycolate for measurement. The ion chromatography method can be further formulated according to ASTM D5827-22.

[0087] The inventors of this invention have discovered that ion exchange resins (used in cooling systems of electrical systems to maintain the low conductivity of the coolant) readily remove dyes, even very weakly ionic or polar, uncharged dyes. This invention protects dyes that may be contained in heat transfer fluids from absorption by ion exchange resins, and thus allows the heat transfer fluid to maintain the benefits gained from the use of dyes.

[0088] In a preferred embodiment of the invention, the heat transfer fluid comprises a dye. As used herein, the term "dye" should be interpreted as any molecule capable of providing visible coloration at a concentration of 0.01 wt.% (based on the total weight of the heat transfer fluid). In a preferred embodiment, the dye comprises at least one of the following chromophores: anthraquinone, triphenylmethane, diphenylmethane, azo-containing compounds, diazo-containing compounds, triazo-containing compounds, diazo-containing compounds, xanthones, acridine, indene, phthalocyanine, azaannulene, nitroso, nitro, diarylmethane, triarylmethane, methine, indamine, azazine, oxazine, thiazine, quinoline, indigo, indophenol, lactone, aminoketone, hydroxyketone, stilbene, thiazole, one or more conjugated aromatic groups, one or more conjugated heterocyclic groups, one or more conjugated carbon-carbon double bonds (e.g., carotene), and combinations thereof. In all embodiments of the invention, the dye differs from zwitterionic compounds. In a preferred embodiment, the dye comprises at least one of anthraquinone, acridine, thiazole, an azo-containing compound, triarylmethane, diarylmethane, or combinations thereof. In a particularly preferred embodiment, the dye comprises an azo-containing compound as a chromophore. In embodiments, the dye for the heat transfer fluid will comprise at least one or more conjugated aromatic groups as chromophores. In a preferred embodiment, the dye is weakly ionic or nonionic, preferably nonionic.

[0089] In some embodiments of the invention, the chromophore of the dye comprises a side amine group. Commercially available dyes of this type include Acid Blue 25, Reactive Blue 19, Disperse Blue 19, Disperse Blue 1, Solvent Blue 35, Crystal Violet, Malachite Green, Brilliant Green, Auramine O, Methyl Orange, Orange G, Congo Red, Direct Blue 15, Direct Red 80, Acid Red 114, Direct Black 38, Acid Black 1, Direct Red 28, Direct Blue 71, Rhodamine B, Rhodamine 6G, or combinations thereof. In a preferred embodiment of the invention, the dye is present in the heat transfer fluid in an amount less than 0.2 wt.%, preferably less than 0.1 wt.%, and most preferably less than 0.05 wt.% based on the total weight of the heat transfer fluid. In a preferred embodiment of the invention, the dye is present in the heat transfer fluid in an amount from 0.000001 to 0.2 wt.%, preferably from 0.000005 to 0.1 wt.%, and most preferably from 0.000005 to 0.05 wt.% based on the total weight of the heat transfer fluid. The ratio (w / w) of the zwitterionic compound to the dye in the heat transfer fluid is preferably at least 30:1, preferably at least 50:1. In some embodiments, the ratio is preferably at least 100:1, preferably at least 200:1, more preferably at least 400:1, more preferably at least 500:1, more preferably at least 1000:1, more preferably at least 3000:1, more preferably at least 5000:1, and most preferably at least 10000:1. The ratio (w / w) of the zwitterionic compound to the dye in the heat transfer fluid is not particularly limited (as it depends on the dye strength), but may be less than 1,000,000:1, such as less than 500,000:1, or less than 100,000:1.

[0090] In a preferred embodiment of the invention, the heat transfer fluid comprises a dye as described herein, wherein the dye has a lower binding affinity for the ion exchange resin than the zwitterionic compound has for the ion exchange resin. Preferably, the heat transfer fluid comprises a dye as described herein, wherein the dye has a lower binding affinity for the ion exchange resin than the zwitterionic compound has for the ion exchange resin, and wherein the zwitterionic compound has a lower binding affinity for the ion exchange resin than the glycolate has for the ion exchange resin.

[0091] In a preferred embodiment of the invention, a method is provided in which the heat transfer fluid comprises a dye as described herein, and wherein the dye has a lesser binding affinity for the ion exchange resin than the zwitterionic compound has for the ion exchange resin. Preferably, a method is provided in which the heat transfer fluid comprises a dye as described herein, and wherein the dye has a lesser binding affinity for the ion exchange resin than the zwitterionic compound has for the ion exchange resin, and wherein the zwitterionic compound has a lesser binding affinity for the ion exchange resin than the glycolate has for the ion exchange resin.

[0092] To determine whether the binding affinity of a dye to an ion exchange resin is less than that of a zwitterionic compound to the ion exchange resin, the following procedure can be used: - Prepare a mixture of 50 ml water, 50 ml monoethylene glycol, 2 ml ion exchange resin, 2 g zwitterionic compound, and 0.01 g dye; - Determine the dye concentration by an appropriate method (e.g., UV-VIS absorbance); - Stir at 20°C for 3 hours; and - Determine the dye concentration by the same method, wherein if the dye concentration loss after stirring is less than 50%, preferably less than 35%, then the binding affinity of the dye to the ion exchange resin is determined to be less than that of the zwitterionic compound to the ion exchange resin.

[0093] To determine whether the binding affinity of the zwitterionic compound to the ion exchange resin is less than that of the glycolate to the ion exchange resin, the following procedure can be used: - Prepare a mixture of 50 ml water, 50 ml monoethylene glycol, 2 ml ion exchange resin, 2 g of the zwitterionic compound, and 0.01 g of glycolic acid; - Determine the total combined concentration of glycolic acid and glycolate by an appropriate method (e.g., ion chromatography); - Stir at 20°C for 3 hours; and - Determine the total combined concentration of glycolic acid and glycolate by the same method, wherein if the loss of glycolate concentration after stirring exceeds 50%, preferably exceeds 80%, then the binding affinity of the zwitterionic compound to the ion exchange resin is determined to be less than that of the glycolate to the ion exchange resin. Those skilled in the art will understand that ion chromatography measures only glycolate ions, but with appropriate sample preparation (addition of a strong base), all glycolic acid present in the sample can be converted to glycolate for measurement. The ion chromatography method can be further modified according to ASTM D5827-22. Additional additives

[0094] As those skilled in the art will understand, based on the teachings presented herein, the heat transfer fluid according to the invention may contain one or more additional additives conventional in the art. Determining how much of a particular additive can be added such that the conductivity of the resulting heat transfer fluid conforms to the invention is within the ordinary capabilities of those skilled in the art. As those skilled in the art will understand, nonionic additional additives are preferred. The heat transfer fluids described herein contain defined amounts of water, alcohol, zwitterionic compounds, azole corrosion inhibitors, or dyes. Thus, one or more additional additives are different from water, alcohol, zwitterionic compounds, azole corrosion inhibitors as previously described herein, or dyes as previously described herein.

[0095] In some embodiments of the invention, the heat transfer fluid provided herein comprises one or more additional additives, preferably selected from the group consisting of corrosion inhibitors, liquid dielectrics, antioxidants, anti-wear agents, detergents, and antifoaming agents. In preferred embodiments, the heat transfer fluid further comprises one or more of the additional additives in an amount ranging from 0.001 to 10 wt.% (based on the total weight of the heat transfer fluid), preferably 0.01 to 5 wt.%, and more preferably 0.02 to 3 wt.%.

[0096] In a preferred embodiment, the heat transfer fluid further comprises one or more additional additives selected from the group consisting of: polyolefins, polyepoxides, silicone oils, silicates (such as Si(OR)4, where R is a C1 to C4 alkyl group), mineral oils, monocarboxylic acids, dicarboxylic acids, and tricarboxylic acids. In a preferred embodiment, the heat transfer fluid of the present invention further comprises one or more of the aforementioned additives in an amount ranging from 0.001 to 10 wt.% (based on the total weight of the heat transfer fluid), preferably 0.01 to 5 wt.%, and more preferably 0.02 to 3 wt.%.

[0097] In a preferred embodiment, the heat transfer fluid further comprises one or more additives selected from the group consisting of: polyolefins, silicone oils, mineral oils, silicates, aliphatic monocarboxylic acids, aliphatic dicarboxylic acids, aliphatic tricarboxylic acids, molybdates, nitrates, nitrites, phosphonates, and phosphates. In a preferred embodiment, the heat transfer fluid of the present invention further comprises one or more of the aforementioned additives in an amount ranging from 0.001 to 10 wt.% (based on the total weight of the heat transfer fluid), preferably from 0.01 to 5 wt.%.

[0098] In embodiments of the invention, the heat transfer fluid comprises an antifoaming agent. Preferably, the antifoaming agent is selected from the group consisting of polyolefins, or silicone polymers (such as 3D silicone polymers), or silicone oils. In embodiments of the invention, a heat transfer fluid as defined herein is provided, wherein the heat transfer fluid further comprises an antifoaming agent in an amount greater than 0.001 wt.% (by total weight of the heat transfer fluid), preferably greater than 0.005 wt.%, preferably greater than 0.01 wt.%, and / or less than 10 wt.%, preferably less than 5 wt.%, preferably less than 3 wt.%.

[0099] In embodiments of the invention, the heat transfer fluid further comprises an antioxidant. Preferably, the antioxidant is selected from the group consisting of: aromatic amines, such as p,p-dioctylaniline, monooctyldiphenylamine, phenothiazine, 3,7-dioctylphenothiazine, phenyl-1-naphthylamine, phenyl-2-naphthylamine, alkylphenyl-1-naphthylamine, and alkylphenyl-2-naphthylmethylene-amine; and sulfur-containing compounds, such as dithiophosphates, phosphites, sulfides, and dithiometallic salts, such as benzothiazole, dialkyltin dithiophosphate, and zinc diaryldithiophosphate. In embodiments of the invention, a heat transfer fluid as defined herein is provided, wherein the heat transfer fluid further comprises an antioxidant in an amount greater than 0.001 wt.% (by total weight of the heat transfer fluid), preferably greater than 0.005 wt.%, preferably greater than 0.01 wt.%, and / or less than 10 wt.%, preferably less than 5 wt.%, preferably less than 3 wt.%.

[0100] In some embodiments of the invention, the heat transfer fluid further comprises a liquid dielectric. Preferred liquid dielectrics are mineral oil, silicone oil, and mixtures thereof. In some embodiments of the invention, the heat transfer fluid provided herein comprises more than 0.0001 wt.% (by total weight of the heat transfer fluid), preferably more than 0.001 wt.%, preferably more than 0.01 wt.%, and / or less than 10 wt.%, preferably less than 5 wt.%, preferably less than 3 wt.% of a liquid dielectric.

[0101] In embodiments of the present invention, the heat transfer fluid further comprises an anionic surfactant, such as an anionic surfactant being a salt of a compound represented by RX; wherein X represents a sulfate group, phosphate group, sulfonate group, or carboxylate group, preferably a sulfate group; and wherein R is selected from: - branched or straight-chain C5-C 24 Alkyl; - Branched or straight-chain monounsaturated C5-C 24 Alkenyl; - Branched or straight-chain polyunsaturated C5-C 24 Alkenyl; - Contains C8-C 15 Alkyl groups; - containing C8-C 15An alkenyl phenyl group; - containing C3-C 15 Alkyl alkylnaphthalene group; - Contains C3-C 15 Alkenyl naphthalene group; - containing C8-C 15 Alkyl groups containing alkylphenol groups; and - containing C8-C 15 The alkenylphenol group.

[0102] In embodiments of the present invention, the heat transfer fluid contains the anionic surfactant in an amount exceeding 0.001 wt.% (based on the total weight of the heat transfer fluid), preferably exceeding 0.005 wt.%, preferably exceeding 0.01 wt.%, and / or less than 10 wt.%, preferably less than 5 wt.%, preferably less than 3 wt.%.

[0103] In embodiments of the invention, a heat transfer fluid as defined herein is provided, wherein the heat transfer fluid further comprises a corrosion inhibitor selected from the group consisting of aromatic carboxylates, aliphatic monocarboxylates, aliphatic dicarboxylates, aliphatic tricarboxylates, molybdates, and phosphates. As those skilled in the art will understand, the carboxylates mentioned herein are typically provided in the form of in-situ neutralized free acids.

[0104] In embodiments of the present invention, the heat transfer fluid further comprises an aliphatic monocarboxylate, preferably selected from C4-C. 12 Aliphatic monocarboxylates are grouped into aliphatic monocarboxylates, wherein the amount is greater than 50 ppm (by weight), preferably greater than 100 ppm, preferably greater than 500 ppm and / or less than 5000 ppm, preferably less than 2500 ppm, and preferably less than 1000 ppm. The amounts of carboxylates mentioned herein are calculated based on the weight of the carboxylate anion (excluding the weight of the cation).

[0105] In embodiments of the present invention, the heat transfer fluid further comprises an aliphatic dicarboxylate, preferably selected from C6-C. 16 Aliphatic dicarboxylates of the group consisting of aliphatic dicarboxylates, wherein the amount is greater than 50 ppm (by weight), preferably greater than 100 ppm, preferably greater than 500 ppm and / or less than 5000 ppm, preferably less than 2500 ppm, and preferably less than 1000 ppm. The amounts of carboxylate mentioned herein are calculated based on the weight of the carboxylate anion (excluding the weight of the cation).

[0106] In embodiments of the present invention, the heat transfer fluid further comprises an aliphatic tricarboxylate, preferably selected from C7-C. 18Aliphatic tricarboxylate salts of the group consisting of aliphatic tricarboxylate salts, wherein the amount is greater than 50 ppm (by weight), preferably greater than 100 ppm, preferably greater than 500 ppm and / or less than 5000 ppm, preferably less than 2500 ppm, and preferably less than 1000 ppm. The amounts of carboxylate salts mentioned herein are calculated based on the weight of the carboxylate anion (excluding the weight of the cation).

[0107] In embodiments of the invention, the heat transfer fluid further comprises an aromatic carboxylate, preferably an aromatic carboxylate selected from the group consisting of benzoates, benzene-1,2-dicarboxylate, benzene-1,2,3-tricarboxylate, benzene-1,2,4-tricarboxylate, benzene-1,4-dicarboxylate, and combinations thereof, in an amount exceeding 50 ppm (by weight), preferably exceeding 100 ppm, preferably exceeding 500 ppm and / or less than 5000 ppm, preferably less than 2500 ppm, and preferably less than 1000 ppm. The amounts of carboxylates mentioned herein are calculated based on the weight of the carboxylate anion (excluding the weight of the cation).

[0108] In embodiments of the invention, the heat transfer fluid further comprises a corrosion inhibitor of molybdate, preferably inorganic molybdate, in an amount exceeding 1 ppm (by weight) of molybdate, preferably exceeding 10 ppm, preferably exceeding 100 ppm of molybdate, and / or less than 10,000 ppm, preferably less than 1,000 ppm, preferably less than 500 ppm. If the molybdate is used in the form of a salt, the amount of molybdate as used herein refers to the amount of molybdate anions (i.e., excluding the weight of cationic counterions).

[0109] In embodiments of the invention, the heat transfer fluid further comprises a corrosion inhibitor of phosphate, preferably inorganic phosphate, in an amount exceeding 10 ppm (by weight) of phosphate, preferably exceeding 250 ppm, preferably exceeding 1000 ppm of phosphate, and / or less than 10000 ppm, preferably less than 5000 ppm, preferably less than 2500 ppm. If the phosphate is used in the form of a salt, the amount of phosphate as used herein refers to the amount of phosphate anions (i.e., excluding the weight of cationic counterions).

[0110] In embodiments of the present invention, the heat transfer fluid further comprises a silicate corrosion inhibitor in an amount exceeding 1 ppm Si (by weight), preferably exceeding 10 ppm Si, most preferably exceeding 100 ppm Si, and / or less than 10,000 ppm, preferably less than 1,000 ppm, and preferably less than 500 ppm. The silicate corrosion inhibitor is preferably selected from the group consisting of: inorganic silicates (such as sodium metasilicate), organosilicates (such as Si(R...)...)...1 ) n (OR 2 ) 4-n , where R 1 and R 2 Each is independently a C1 to C6 alkyl or phenyl, and wherein n is 0, 1, 2 or 3) or silica (SiO2) nanoparticles (such as silica nanoparticles having a volume median particle size (Dv50) in the range of 10-200 nm).

[0111] In embodiments of the invention, the heat transfer fluid further comprises nitrates, preferably inorganic nitrates, in an amount exceeding 1 ppm (by total weight of the heat transfer fluid), preferably exceeding 10 ppm, preferably exceeding 100 ppm, and / or less than 10,000 ppm, preferably less than 1,000 ppm, preferably less than 500 ppm. If the nitrates are used in the form of salts, the amount of nitrates as used herein refers to the amount of nitrate anions (i.e., excluding the weight of cationic counterions).

[0112] In embodiments of the invention, the heat transfer fluid further comprises nitrite, preferably inorganic nitrite, in an amount exceeding 1 ppm (by total weight of the heat transfer fluid), preferably exceeding 10 ppm, preferably exceeding 100 ppm, and / or less than 10,000 ppm, preferably less than 1,000 ppm, preferably less than 500 ppm. If the nitrite is used in the form of a salt, the amount of nitrite as used herein refers to the amount of nitrite anions (i.e., excluding the weight of cationic counterions).

[0113] In embodiments of the invention, the heat transfer fluid further comprises phosphonates, preferably inorganic phosphonates, in an amount exceeding 10 ppm (by total weight of the heat transfer fluid), preferably exceeding 250 ppm, preferably exceeding 1000 ppm, and / or less than 10000 ppm, preferably less than 5000 ppm, preferably less than 2500 ppm. If the phosphonate is used in the form of a salt, the amount of phosphonate as used herein refers to the amount of phosphonate anions (i.e., excluding the weight of cationic counterions).

[0114] The inventors of this invention have discovered that, when used as a heat transfer fluid, particularly when considering the ability to maintain low conductivity while preserving the same performance during corrosion inhibition and aging at elevated temperatures in the presence of metals, the inclusion of certain additional additives in the heat transfer fluid of this invention can particularly improve one or more of the properties of the composition. Such particularly preferred additives (referred to herein as “enhancing additives”) include nonionic polymers, amines, aromatic alcohols, dioxo-aromatic compounds, and nonionic surfactants. These are described in more detail in the following paragraphs.

[0115] In a preferred embodiment of the invention, the heat transfer fluid further comprises a nonionic polymer selected from the group consisting of: polyvinylpyrrolidone, polyvinyl alcohol, polyepoxide, polysiloxane, and C1-C of polyepoxide. 18 C1-C of alkyl or alkenyl ethers and polyepoxides 18 Alkyl or alkenyl esters, alkoxylated C1-C 18 Alkyl or alkenylamines, polyvinyl acetate, copolymers thereof, and combinations thereof, preferably nonionic polymers selected from polyvinylpyrrolidone. The nonionic polymer preferably has a weight-average molecular weight M in the range of 100 to 5,000,000 g / mol, preferably 500 to 2,500,000 g / mol. wThe polyepoxide is preferably selected from polyethylene oxide, polypropylene oxide, polybutane, and copolymers thereof. Polyvinylpyrrolidone (PVP) may be selected from PPVP homopolymers and PPVP copolymers, preferably PPVP homopolymers. Examples of suitable PPVP copolymers include polymers of N-vinylpyrrolidone with at least one other monomer selected from styrene, vinyl acetate, ethylene, propylene, tetrafluoroethylene, methyl methacrylate, vinyl chloride, and ethylene oxide. In such embodiments, the percentage of N-vinylpyrrolidone monomer is at least 10%, more preferably at least 25%, such as at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95%, based on the total number of monomers in the PPVP copolymer. Preferred polyvinylpyrrolidone copolymers applicable in heat transfer fluids include copolymers of N-vinylpyrrolidone and vinyl acetate, wherein the percentage of N-vinylpyrrolidone monomers is at least 25% based on the total number of monomers in the polyvinylpyrrolidone copolymer; hydrolyzed forms of copolymers of N-vinylpyrrolidone and vinyl acetate, wherein the percentage of N-vinylpyrrolidone monomers is at least 10% based on the total number of monomers in the polyvinylpyrrolidone copolymer; and copolymers of N-vinylpyrrolidone and N-vinylcaprolactam, wherein the percentage of N-vinylpyrrolidone monomers is at least 40% based on the total number of monomers in the polyvinylpyrrolidone copolymer. Polyvinylpyrrolidone, preferably a polyvinylpyrrolidone homopolymer, preferably has a weight-average molecular weight M in the range of 100 to 5,000,000 g / mol, preferably 500 to 2,500,000 g / mol. w As understood by those skilled in the art, weight-average molecular weight is the weight fraction of molecules in a polymer sample and provides an average value of the molecular mass of individual macromolecules in the polymer sample. Weight-average molecular weight, as defined herein, is determined using the following equation: Those skilled in the art are familiar with different techniques for determining the weight-average molecular weight of polymers with different chain lengths. The weight-average molecular weight and the corresponding measurement method are typically indicated on the product data sheet of the polymer under consideration. In specific embodiments of the invention, polyvinylpyrrolidone, preferably polyvinylpyrrolidone homopolymers, have a weight-average molecular weight in the range of 3,000 to 2,500,000 g / mol, preferably in the range of 5,000 to 2,250,000 g / mol, more preferably in the range of 7,500 to 200,000 g / mol, and even more preferably in the range of 8,000 to 1,800,000 g / mol. Polyvinylpyrrolidone suitable for use as an additive is available from commercial suppliers such as BASF, Sigma-Aldrich, or Nippon Shokubai. An example of commercially available polyvinylpyrrolidone is Luvitec K17 (M W = 9,000 g / mol), Luvitec K30 (M W = 50,000 g / mol), Luvitec K90 (M W = 1,400,000 g / mol) and PVP K30. In embodiments of the invention, the heat transfer fluid contains a nonionic polymer as an additional additive in an amount exceeding 0.001 wt.% (by total weight of the heat transfer fluid), preferably exceeding 0.005 wt.%, preferably exceeding 0.01 wt.%, and / or less than 10 wt.%, preferably less than 5 wt.%, preferably less than 3 wt.%.

[0116] In a preferred embodiment of the invention, the heat transfer fluid further comprises an amine. The amine is preferably a molecule selected from free atoms C, N, H and optionally O, containing 1 to 10 C atoms, containing one or more amine functional groups and optionally containing one or more hydroxyl or ether functional groups, and preferably wherein the amine does not contain any functional groups other than one or more amine functional groups and optionally one or more hydroxyl or ether functional groups. In a preferred embodiment, the amine is selected from the group consisting of: methylamine, dimethylamine, trimethylamine, ethylamine, isopropylamine, tributylamine, triethylamine, 2-dimethylaminoethanol, 2-diethylaminoethanol, monoethanolamine, 2-amino-2-methyl-1-propanol, ethoxylated octylamine, diisopropylamine, 2-dibutylaminoethanol, 2-dipropylaminoethanol, triethanolamine, tri(isopropanol)amine, ethylenediamine, piperadine, morphine, etc. Phosphine, pyrrolidine, piperazine, diisopropylmethylamine, 1,4-diazabicyclo[2.2.2]octane, quinine ring, ethanolamine, diethanolamine, benzylamine, cyclohexylamine, hexylamine, dicyclohexylamine, isobutanolamine, dihydroxyethylamine, 3-methoxypropylamine, p,p-dioctylaniline, monooctyldiphenylamine, phenyl-1-naphthylamine, phenyl-2-naphthylamine, alkylphenyl-1-naphthylmethyleneamine, alkyl-phenyl-2-naphthylmethyleneamine, alkoxylated C1-C 22 Hydrocarbon amines (particularly ethoxylated octylamine, such as 2-EO-octylamine) and combinations thereof. In embodiments of the invention, the heat transfer fluid contains an amine as an additional additive in an amount exceeding 0.001 wt.% (based on the total weight of the heat transfer fluid), preferably exceeding 0.005 wt.%, preferably exceeding 0.01 wt.%, and / or less than 10 wt.%, preferably less than 5 wt.%, preferably less than 3 wt.%.

[0117] In embodiments of the invention, the heat transfer fluid described herein further comprises an aromatic alcohol selected from phenols, pyrogallols, gallic acids, gallic esters, and combinations thereof. The phenol is preferably selected from phenols optionally having 0, 1, 2, or 3 substituents independently selected from amino, C1-C6 alkyl groups. Suitable and preferred examples of phenols include 2-aminophenol, 4-aminophenol, 2-amino-4-methylphenol, 2,6-di-tert-butylmethylphenol, 4,4'-methylene-bis(2,6-di-tert-butylphenol), and 4-amino-3-methylphenol. Suitable and preferred examples of gallic esters include C1-C6 gallic esters. 12 Alkyl esters. In embodiments of the invention, the heat transfer fluid contains an aromatic alcohol as an additional additive in an amount exceeding 0.001 wt.% (based on the total weight of the heat transfer fluid), preferably exceeding 0.005 wt.%, preferably exceeding 0.01 wt.%, and / or less than 10 wt.%, preferably less than 5 wt.%, preferably less than 3 wt.%.

[0118] In embodiments of the invention, the heat transfer fluid further comprises a dioxo-aromatic compound selected from benzoquinone, naphthoquinone, hydroquinone, and catechol. The dioxo-aromatic compound is preferably selected from 1,4-benzoquinone, 1,2-benzoquinone, 1,2-naphthoquinone, 1,4-naphthoquinone, 1,4-dihydroxybenzene, and 1,2-dihydroxybenzene, optionally having 0, 1, or 2 substituents independently selected from amino, C1-C6 alkyl, or sulfonic acid groups. In embodiments of the invention, the heat transfer fluid comprises a dioxo-aromatic compound as an additional additive in an amount exceeding 0.001 wt.% (based on the total weight of the heat transfer fluid), preferably exceeding 0.005 wt.%, preferably exceeding 0.01 wt.%, and / or less than 10 wt.%, preferably less than 5 wt.%, preferably less than 3 wt.%.

[0119] In embodiments of the invention, the heat transfer fluid further comprises an auxiliary antioxidant selected from thiols, thioethers, and thioesters, such as those selected from: methyl mercaptan, ethyl mercaptan, n-propyl mercaptan, 2-propene mercaptan, butane mercaptan, tert-butyl mercaptan, thiophenol, thioacetic acid, dimercaptosuccinic acid, glutathione, cysteine, methyl thiobenzoate, dimethyl sulfide, methyl phenyl sulfide, 4-ethylthio-2-methylpent-2-ene, dimethyl sulfide, diethyl sulfide, diphenyl sulfide, phenyl 4-piperidinyl sulfide, and thiodiethylene glycol.

[0120] In embodiments of the invention, the heat transfer fluid further comprises a nonionic surfactant. The nonionic surfactant is preferably selected from the group consisting of: • fatty acid esters, such as sorbitol fatty acid esters; • polyalkylene glycols; • polyalkylene glycol esters; • copolymers and block copolymers of ethylene oxide and propylene oxide; • polyoxyethylene derivatives of sorbitol fatty acid esters; and • alkoxylated alcohol ethers.

[0121] In embodiments of the present invention, the heat transfer fluid contains a nonionic surfactant as an additional additive in an amount exceeding 0.001 wt.% (based on the total weight of the heat transfer fluid), preferably exceeding 0.005 wt.%, preferably exceeding 0.01 wt.%, and / or less than 10 wt.%, preferably less than 5 wt.%, preferably less than 3 wt.%.

[0122] In some embodiments of the invention, the heat transfer fluid comprises a polymeric dye. As those skilled in the art will understand, such a large polymeric dye minimizes interaction with the ion exchange resin. Commercially available examples of suitable dyes include Liquidint® Red ST or other similar polymeric colorants from Milliken Chemical, Inc., Spartanburg, SC, USA, or colorants (e.g., Liquidint® Blue RE) from Chromatek, Inc., Canton, Mich., USA. Other illustrative colorants include the following: Liquitint Red ST, Liquitint Blue RE, Liquitint Red BL, Liquitint Yellow II, Liquitint Sunbeam Yellow, Liquitint Supra yellow, Liquitint Green HMC, Liquitintviolet, Liquitint Red BL, Liquitint Red RL, Liquitint Cherry Red, Liquitint RedII, Liquitint Teal, Liquitint Yellow LP, Liquitint Violet LS, Liquitint Crimson, Liquitint Aquamarine, Liquitint Green HMC, Liquidint Red HN, Liquidint Red ST, and combinations thereof. In one exemplary embodiment, the dye will be at least one of Liquidint Red, Liquidint Yellow, Liquidint Patent Blue, or combinations thereof. Concentrate

[0123] In embodiments of the invention, the heat transfer fluid as described herein is provided in the form of a concentrate.

[0124] In preferred embodiments, the concentrate is suitable for preparing the heat transfer fluid described herein by adding water and / or alcohol; preferably water, monoethylene glycol, monopropylene glycol, 1,3-propanediol and / or glycerol; most preferably water. In highly preferred embodiments, the concentrate is suitable for preparing the heat transfer fluid solely by adding water and / or alcohol; preferably only water (i.e., the heat transfer fluid described herein can be prepared from the concentrate without adding any other components).

[0125] In a preferred embodiment, a concentrate is provided wherein the concentration of zwitterions is at least 5 wt.%, preferably at least 10 wt.%, more preferably at least 15 wt.%, and most preferably at least 20 wt.%. Preparation method

[0126] In another aspect of the invention, a method for preparing a heat transfer fluid as defined herein is provided, the method comprising the steps of: (i) providing zwitterions as defined herein; (ii) providing a base fluid as defined herein; (iii) optionally providing additional additives as defined herein; and (iv) combining the zwitterions of step (i) with the base fluid of step (ii) and the optional additional additives of step (iii) to obtain a heat transfer fluid.

[0127] According to the present invention, the order in which the compounds are added is not particularly restricted.

[0128] In some embodiments, a method for preparing a heat transfer fluid as defined herein is provided, the method comprising the steps of: (i) providing a concentrate as defined herein; (ii) providing water, alcohol, or a mixture thereof; and (iii) combining the concentrate of step (i) with the water, alcohol, or mixture thereof of step (ii) to obtain a heat transfer fluid. Method for exchanging heat

[0129] In some embodiments, the present invention provides a method for exchanging heat, the method comprising the steps of: a. providing a heat transfer fluid comprising a base liquid and a zwitterionic compound; b. providing a cooling system configured to thermally contact the heat transfer fluid with an electrical system, the cooling system comprising an ion exchange resin; c. transferring heat from the electrical system to the heat transfer fluid; and d. contacting the heat transfer fluid with the ion exchange resin; wherein the base liquid is composed of water, or an alcohol, or a mixture thereof; wherein the heat transfer fluid provided in step (a) has a conductivity at 25°C of less than 100 µS / cm, preferably less than 50 µS / cm, more preferably less than 25 µS / cm, more preferably less than 10 µS / cm, and most preferably less than 5 µS / cm.

[0130] In a preferred embodiment, the volume ratio of the heat transfer fluid to the ion exchange resin is at least 1:99 v / v%, preferably at least 5:95 v / v%, more preferably at least 10:90 v / v%, and most preferably at least 20:80 v / v.

[0131] The cooling system, heat transfer fluid, and ion exchange resin are preferably as described herein in the context of the heat transfer fluid of this invention. Therefore, the embodiments of the cooling system (particularly its other components), heat transfer fluid (particularly conductivity, the compounds contained therein, and their concentration) and ion exchange resin described herein in the context of the heat transfer fluid are adapted to the method of this invention with necessary modifications. Cooling System

[0132] A cooling system typically includes additional components such as heat exchangers (typically configured to exchange heat with ambient air, such as radiators) for transferring heat from the heat transfer fluid, one or more pumps, one or more valves, and conduits for connecting the various components of the cooling system. Together, the components of the cooling system define the flow path of the heat transfer fluid.

[0133] In a highly preferred embodiment, the ion exchange resin is positioned within the flow path of the heat transfer fluid. In some embodiments, the cooling system of step (b) comprises the ion exchange resin in a column. In other embodiments, the ion exchange resin may be fixed to the inner surface of the cooling system, for example, to a porous carrier or bed of the cooling system of step (b) in a manner such that the ion exchange resin can contact the heat transfer fluid of step (a) during use.

[0134] In some embodiments of the invention, the cooling system of step (b) includes a bypass through which heat transfer fluid is directed to the ion exchange resin. In a preferred embodiment, for each cycle through the coolant system, at least 10 v / v%, preferably at least 15 v / v%, more preferably at least 20 v / v%, and most preferably 30 v / v% of heat transfer fluid flows through the ion exchange resin. In some embodiments, this bypass is always open, such that the heat transfer fluid contacts the ion exchange resin in each cycle through the coolant system. In other embodiments, the bypass is periodically closed and reopened, such that heat transfer periodically contacts the ion exchange resin, preferably at least once in every five cycles through the coolant system, preferably at least once in every three cycles through the coolant system, and more preferably at least once in every two cycles through the coolant system.

[0135] In some embodiments of the invention, the cooling system of step (b) includes a bypass through which heat transfer fluid is directed to the ion exchange resin. In a preferred embodiment, for each cycle through the coolant system, at least 10 v / v%, preferably at least 15 v / v%, more preferably at least 20 v / v%, and most preferably 30 v / v% of heat transfer fluid flows through the ion exchange resin. In some embodiments, this bypass is always open, such that the heat transfer fluid contacts the ion exchange resin in each cycle through the coolant system. In other embodiments, the bypass is periodically closed and reopened, such that heat transfer periodically contacts the ion exchange resin, preferably at least once in every five cycles through the coolant system, preferably at least once in every three cycles through the coolant system, and more preferably at least once in every two cycles through the coolant system.

[0136] Cooling systems are typically designed to prevent contact between the heat exchange fluid and the air, thereby avoiding, in particular, the decomposition of the base fluid. Therefore, the flow path of the heat transfer fluid in a cooling system is preferably substantially isolated from the air.

[0137] In some embodiments of the present invention, the method further includes the step of passing a heat transfer fluid through a heat exchanger and transferring heat from the heat transfer fluid.

[0138] According to the invention, the heat transfer fluid typically circulates within the cooling system, such that steps (c) and (d) are performed simultaneously and continuously. However, in some embodiments, the ion exchange resin may be separated from a portion of the cooling circuit by one or more valves, allowing step (c) to be performed continuously without requiring step (d) to be performed continuously. Step (d) may then be performed at predetermined intervals or in response to user actions or sensor data, such as sensor data including information about the pH and / or conductivity of the heat transfer fluid.

[0139] In a highly preferred embodiment of the invention, throughout the method, the electrical conductivity of the heat transfer fluid is maintained at less than 100 µS / cm, preferably less than 50 µS / cm, more preferably less than 25 µS / cm, even more preferably less than 10 µS / cm, and most preferably less than 5 µS / cm. Electrical system

[0140] In a preferred embodiment of the invention, the method further includes the step of generating heat in the electrical system.

[0141] The electrical system is preferably selected from the group consisting of: solar energy systems, fuel cell units, electric motors, generators, batteries, battery-electric vehicles, DC / DC converters, DC / AC converters, telephone transmission systems, power electronic devices, radio and television broadcasting stations, relay stations, and electric heating or cooling devices, preferably fuel cell units, batteries, or power electronic devices. Ion exchange resins and their pretreatment.

[0142] Suitable ion exchange resins in the context of this invention include anion exchange resins, cation exchange resins, mixed ion exchange resins, and combinations thereof. As used herein, a mixed ion exchange resin refers to a resin having a combination of anion exchange and cation exchange functionalities. This can be achieved through chemical design in the same resin or by simply mixing anion exchange resins and cation exchange resins. In some embodiments of the invention, the resin comprises a combination of two or more resins, for example, arranged such that a heat transfer fluid circulates first through a first resin and then through a second resin, such as first through an anion exchange resin followed by a mixed ion exchange resin.

[0143] The resin is preferably a polymer resin. Typically, the resin comprises a polymer backbone having ion exchange sites introduced after polymerization, such as sulfonate groups, phosphonate groups, hypophosphonate groups, quaternary ammonium groups, carboxylate groups, etc. The polymer backbone is preferably selected from polystyrene, polystyrene-styrene copolymers, polyacrylates, aromatic-substituted vinyl copolymers, polymethacrylates, phenol-formaldehyde, polyalkylamines, and combinations thereof. In embodiments of the invention, the polymer backbone is selected from polystyrene-styrene copolymers, polyacrylates, and polymethacrylates. In embodiments of the invention, the polymer backbone is selected from styrene-divinylbenzene copolymers. In embodiments of the invention, the ion exchange sites in the cation exchange resin include sulfonate, phosphonate, and / or carboxylic acids. In some embodiments of the invention, the ion exchange sites are amino groups (such as primary, secondary, and / or tertiary amino acids) and quaternary ammonium groups. In embodiments of the invention, the ion exchange sites in the anion exchange resin include quaternary ammonium groups. Examples of suitable quaternary ammonium groups are benzyltrimethylammonium, benzyldimethylethanolammonium, trialkylbenzylammonium, trimethylbenzylammonium, or dimethyl-2-hydroxyethylbenzylammonium and combinations thereof. In embodiments of the invention, the ion exchange resin is a cation exchange resin containing a sulfonic acid group (-SO3H). Such ion exchange resins include sodium polystyrene or poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (polyAMPS).

[0144] In a preferred embodiment, the ion exchange resin is a mixed ion exchange resin comprising a combination of cation exchange sites containing sulfonic acid and anion exchange sites containing trimethylammonium.

[0145] Commercially available ion exchange resins suitable for use in this paper are available from DuPont as Amberlite™, Amberjet™, Duolite™, and Imac™ resins; Bayer as Lewatit™ resin from Leverkusen, Germany; Dow Chemical as Dowex™ resin from Midland, Michigan; Mitsubishi Chemical as Diaion™ and Relite™ resins from Tokyo, Japan; Purolite as Purolite™ resin from BalaCynwyd, Pa.; Sybron as Ionac™ resin from Birmingham, NJ; and Resintech from West Berlin, NJ. In one embodiment, a suitable commercially available ion exchange resin would be Dowex™ MR-3 LC NG Mix mixed-bed resin, Dowex™ MR-450 UPW mixed-bed resin, Sybron Ionac™ NM-60 mixed-bed resin, Amberlite™ MB-150, or AmberLite. TM IRN170 H / OH mixed-bed resin, while in an exemplary embodiment, a suitable commercially available ion exchange resin would be AmberLite. TM IRN170H / OH. References to trade names in this document should be interpreted as referring to products sold under that trade name on October 1, 2023.

[0146] The inventors of this invention have found that resin pretreatment (e.g., by soaking the resin) is not necessary and can in fact be avoided by using zwitterionic compounds, as explained throughout this specification. However, in some cases, resin pretreatment may still be desirable. Therefore, in embodiments of the invention, the ion exchange resin of the heat exchange system is pretreated by contacting the resin with a heat transfer fluid containing a zwitterionic compound before contacting the resin with the heat transfer fluid. In a preferred embodiment of the invention, the contact between the ion exchange resin and the zwitterionic compound lasts for a period of time sufficient to allow the zwitterionic compound to exchange positions with at least 15% of the total exchangeable groups based on the total number of exchangeable ions in the ion exchange resin. In some embodiments, the ion exchange resin is soaked in a solution containing a zwitterionic compound for at least 5 min, preferably at least 20 min, more preferably at least 12 hours, and most preferably at least 24 hours. In some embodiments, a solution containing a zwitterionic compound of at least one bed volume, preferably at least two bed volumes, is circulated through the bed of the ion exchange resin before the resin is contacted with the heat transfer fluid. The solution containing the zwitterionic compound preferably contains at least 0.5 wt.% (by total weight of the solution), and preferably at least 1 wt.% of the zwitterionic compound. In some embodiments of the invention, a method is provided that further includes the step of pretreating the resin by contacting the ion exchange resin of the cooling system with the solution containing the zwitterionic compound, as described herein.

[0147] As illustrated in the accompanying examples, the inventors of this invention have discovered that the zwitterionic compounds according to the invention can protect corrosion inhibitors and / or dyes from being absorbed by the resin, while still allowing ionic compounds (such as glycolates) to be absorbed by the resin. Not wishing to be bound by any theory, the inventors of this invention believe this is because the resin's affinity for zwitterionic compounds is greater than its affinity for corrosion inhibitors or dyes, but less than its affinity for charged ions (such as glycolate ions). Therefore, in a preferred embodiment of the invention, a method is provided in which the binding affinity of the zwitterionic compound to the ion exchange resin is less than the binding affinity of the glycolate to the ion exchange resin.

[0148] As also shown in the accompanying examples, it is particularly advantageous to employ a combination of two or more zwitterionic compounds as described herein, especially when the ion exchange resin contains both anion exchange and cation exchange functionalities. By using a combination of two or more zwitterionic compounds, optimal protection of both corrosion inhibitors and dyes can be achieved. In some preferred embodiments of the invention, particularly when the ion exchange resin contains both anion exchange and cation exchange functionalities, the zwitterionic compound comprises a combination of first and second zwitterionic compounds, wherein the first and second zwitterionic compounds are preferably as previously described generally regarding zwitterionic compounds, and more preferably the first zwitterionic compound contains a trialkylammonium functional group, and the second zwitterionic compound contains a sulfonic acid functional group. Cooling system of the invention

[0149] In another aspect of the invention, a cooling system comprising the heat transfer fluid of the invention is provided, wherein the cooling system comprises an ion exchange resin in contact with the heat transfer fluid.

[0150] The heat transfer fluid and ion exchange resin are preferably as described previously herein. Therefore, the embodiments of the heat transfer fluid (particularly conductivity, the compounds contained therein, and their concentration) defined herein, the methods using this heat transfer fluid, and the ion exchange resin, are adapted, with necessary modifications, to the cooling system of the present invention. Uses of the Invention

[0151] In another aspect of the invention, the use of a heat transfer fluid comprising a base liquid and a zwitterionic compound according to formula (Ia) or (Ib) as a heat transfer fluid in a cooling system comprising an ion exchange resin is provided, wherein the base liquid is composed of water, or an alcohol, or a mixture thereof; and wherein the heat transfer fluid has a conductivity at 25°C of less than 100 µS / cm, preferably less than 50 µS / cm, more preferably less than 25 µS / cm, more preferably less than 10 µS / cm, and most preferably less than 5 µS / cm.

[0152] In another aspect of the invention, the use of a heat transfer fluid comprising a base liquid and a zwitterionic compound as a heat transfer fluid in a cooling system comprising an ion exchange resin is provided, wherein the base liquid is composed of water, or an alcohol, or a mixture thereof; and wherein the heat transfer fluid has a conductivity at 25°C of less than 100 µS / cm, preferably less than 50 µS / cm, more preferably less than 25 µS / cm, more preferably less than 10 µS / cm, and most preferably less than 5 µS / cm; wherein - The base fluid contains alcohols selected from the group consisting of: monoethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, hexaethylene glycol, monopropylene glycol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, pentapropylene glycol, hexapropylene glycol, methanol, ethanol, propanol, butanol, tetrahydrofurfuryl alcohol, ethoxylated furfuryl alcohol, dimethyl ether of glycerol, sorbitol, 1,2,6-hexanetriol, trimethylolpropane, methoxyethanol, glycerol, and mixtures thereof, preferably alcohols selected from the group consisting of: monoethylene glycol, monopropylene glycol, 1,3-propanediol, glycerol, and mixtures thereof; or - the zwitterionic compound is not N,N,N-trimethylglycine, preferably the heat transfer fluid does not contain N,N,N-trimethylglycine; or - wherein the heat transfer fluid further contains a corrosion inhibitor, and wherein the ratio (w / w) of the zwitterionic compound to the corrosion inhibitor in the heat transfer fluid is less than 50. : 1, more preferably less than 30 : 1; or - wherein the concentration of the zwitterionic compound in the heat transfer fluid is less than 6 wt.%, more preferably less than 4 wt.%, and most preferably less than 3 wt.% based on the total weight of the heat transfer fluid.

[0153] The cooling system, heat transfer fluid, and ion exchange resin are preferably as described previously herein. Therefore, the embodiments of the cooling system (in particular its other components), heat transfer fluid (in particular conductivity, the compounds contained therein, and their concentration) and ion exchange resin described previously herein are adapted to the purposes of this invention with the necessary modifications.

[0154] The preferred application is as a heat transfer fluid in a cooling system for an electrical system, wherein the electrical system is preferably as described above in the context of the method.

[0155] In another aspect of the invention, the zwitterionic compound is provided for the following uses: • for prolonging the corrosion inhibition properties of a heat transfer fluid containing a corrosion inhibitor when in contact with an ion exchange resin, preferably when used as a heat transfer fluid in a cooling system containing an ion exchange resin in contact with the heat transfer fluid; • for prolonging the coloring of a heat transfer fluid containing a dye when in contact with an ion exchange resin, preferably when used as a heat transfer fluid in a cooling system containing an ion exchange resin in contact with the heat transfer fluid; • for reducing the corrosion of the heat transfer fluid used in the heat transfer fluid when the heat transfer fluid containing the dye is used as a heat transfer fluid when in contact with an ion exchange resin, preferably when used as a heat transfer fluid in a cooling system containing an ion exchange resin in contact with the heat transfer fluid. The amount of corrosion inhibitor and / or dye; • For extending the service life of ion exchange resins by reducing or avoiding the uptake of heat transfer fluid components when in contact with a heat transfer fluid, preferably when the heat transfer fluid is used in a cooling system containing ion exchange resins in contact with the heat transfer fluid; • For extending the service life of heat transfer fluids containing corrosion inhibitors (and preferably alcohols as described herein) and / or ion exchange resins in contact with the heat transfer fluids by: ○ reducing, delaying or avoiding corrosion; ○ reducing, delaying or avoiding the formation of conductive acids such as glycolates; preferably when the heat transfer fluid is used in a cooling system containing ion exchange resins in contact with the heat transfer fluid.

[0156] The preferred application is as a heat transfer fluid in a cooling system for an electrical system, wherein the electrical system is preferably as described above in the context of the method. Example

[0157] As mentioned in this article, the conductivity is preferably measured according to ASTM D1125-23 using a Mettler-Toledo SevenExcellenceCond meter S700-Std-Kit conductivity meter equipped with a SevenExcellenceCond meter S700-Std-Kit.

[0158] The analysis of anions (glycolate) in the coolant was performed using ion chromatography according to ASTM D5827-22 using Thermo-Scientific Dionex ICS 6000.

[0159] UV-VIS adsorption (1 cm path length, HACH LICO 690) was used to determine the concentrations of Rhodamine B (535 nm) and the dye Acid Green 25 (650 nm).

[0160] Analysis of organic corrosion inhibitors (benzotriazole, toluenetriazole) was performed by reversed-phase HPLC on a Shimadzu Prominence system using an Agilent Zorbax Eclipse Plus C18 column with UV detection.

[0161] The heat transfer fluids shown in Table 1 were prepared. Rhodamine B was added as a dye and toluenetriazole as a corrosion inhibitor to the water-monoethylene glycol-based solution. Subsequently, the heat transfer fluid was reacted with the ion exchange resin Amberlite. TM MB20 HOH (2 v / v%) contact for 3 hours. Table 1

[0162] Table 2 shows the heat transfer fluid properties before and after contact with the ion exchange resin. 'eCond 25°C before resin' indicates the conductivity of the heat transfer fluid before contact with the ion exchange resin. 'eCond 25°C after resin' indicates the conductivity of the heat transfer fluid after contact with the ion exchange resin. 'ΔRhodamine B' represents the percentage change in dye concentration, and 'ΔTTZ' represents the percentage change in corrosion inhibitor concentration. Table 2

[0163] The heat transfer fluids shown in Table 3 were prepared. Chromatint Red X4075 or Acid Green 25 was added as a dye, and benzyltriazole or toluenetriazole was added as a corrosion inhibitor to the water-monoethylene glycol-based solution. Subsequently, the heat transfer fluid was reacted with the ion exchange resin Amberlite. TM MB20 HOH (2 v / v%) contact for 3 hours. Table 3

[0164] Table 4 shows the heat transfer fluid properties before and after contact with the ion exchange resin. 'eCond 25°C before resin' indicates the conductivity of the heat transfer fluid before contact with the ion exchange resin. 'eCond 25°C after resin' indicates the conductivity of the heat transfer fluid after contact with the ion exchange resin. 'ΔRhodamine B' or 'ΔAcid Green 25' indicates the percentage change in dye concentration, 'ΔBenztriazole' or 'ΔTolyltriazole' indicates the percentage change in corrosion inhibitor concentration, and 'Δglycolate' indicates the percentage change in glycolate concentration. Table 4

[0165] As can be seen from the examples and comparative examples above, the inclusion of zwitterionic compounds does not adversely affect conductivity or reduce the resin’s uptake of dyes and corrosion inhibitors, but still allows the resin to perform the desired function of removing glycolate ions.

Claims

1. A heat transfer fluid comprising: at least one zwitterionic compound according to formula (Ia) or (Ib): Where Y is selected from sulfonate (-SO3) - ), phosphite (-HPO2) - ) and phosphonate (-PO3) - ); R 1 R 2 R 3 R 4 R 5 and R 6 The group selected individually is from the group consisting of: hydrogen, =O, -OH, -SH, -NH2, and optionally substituted monovalent hydrocarbon groups having 1 to 30 carbon atoms, preferably R. 1 R 2 R 3 R 4 R 5 and R 6 Choose individually from the following groups: hydrogen, C1-C 20 Alkyl, C1-C 20 Haloalkyl, C1-C 20 Alkyl alcohols, C1-C 20 aminoalkyl, C2-C 20 alkenyl, C3-C8 cycloalkyl, C4-C8 cycloalkenyl, C6-C 10 Aryl, C1-C 20 Thioether, =O, -OH, -NH2, -SH, -OR 7 -NR 7 R 7’ -SR 7 -(OCH2CH2) p CH3、-(OCHCH3CH2) q CH 3、 -(OCH3) r CH3, -R 7 OR 7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’ -R 7 (NHCONH)R 7’ -N=CR 7 R 7’ -N=CR 7’’ C(O)R 7 ;R 7 Choose from the following groups: C1-C 20 Alkyl, C1-C 20 Haloalkyl, C1-C 20 aminoalkyl, C2-C 20 alkenyl, C1-C 20 Alkyl alcohols, -(OCH2CH2) p CH3、-(OCHCH3CH2) q CH3、-(OCH3) r CH3, preferably R 7 Choose freely from C1 to C 20 The group consisting of alkyl groups; R 7’ Choose from the following groups: hydrogen, C1-C 20 Alkyl, C1-C 20 Haloalkyl, C1-C 20 aminoalkyl, C2-C 20 alkenyl, C1-C 20 Alkyl alcohols, -(OCH2CH2) p CH3、-(OCHCH3CH2) q CH3、-(OCH3) r CH3, preferably R 7’ Choose free hydrogen, C1-C 20 The group consisting of alkyl groups; R 7’’ It is a divalent C2-C8 alkyl group, such that -N=CR 7’’ It is a cycloalkyl group; n, m, and o are each individually selected from 0 to 20, preferably 0 to 10 integers; in formulas (Ia) and (Ib), at least one of n, m, and o is > 0; p, q, and r are each individually selected from 1 to 30, preferably 2 to 20 integers; Z is selected from Z 1 Z 2 Z 3 Z 4 Z 5 Z 6 and Z 7 Any one of them, where Z 1 Z 2 Z 3 Z 4 Z 5 Z 6 and Z 7 as follows: R 8 R 9 and R 10 Individually selected from the group consisting of: hydrogen and optionally substituted monovalent hydrocarbon groups having 1 to 30 carbon atoms, preferably R 8 R 9 and R 10 Choose individually from the following groups: hydrogen, C1-C 20 Alkyl, C1-C 20 Haloalkyl, C1-C 20 Alkyl alcohols, C1-C 20 aminoalkyl, C1-C 20 sulfides, -R 7 OR 7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’ -R 7 (NHCONH)R 7’ -N=CR 7 R 7’ -N=CR 7’’ -C(O)R 7 More preferably R 8 R 9 and R 10 Individually selected from the group consisting of: hydrogen, C1-C8 alkyl, C1-C8 haloalkyl, C1-C8 alkyl alcohol, C1-C8 aminoalkyl, C1-C8 sulfide, -R 7 OR 7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’ -R 7 (NHCONH)R 7’ -N=CR 7 R 7’ -N=CR 7’’ -C(O)R 7 ;R 11 R 12 R 13 R 14 and R 15 The group consisting solely of hydrogen and optionally substituted monovalent hydrocarbon groups having 1 to 30 carbon atoms, preferably R, is selected from the group consisting solely of hydrogen and optionally substituted monovalent hydrocarbon groups having 1 to 30 carbon atoms. 11 R 12 R 13 R 14 and R 15 Choose individually from the following groups: hydrogen, C1-C 20 Alkyl, C1-C 20 Haloalkyl, C1-C 20 Alkyl alcohols, C1-C 20 aminoalkyl, C2-C 20 alkenyl, C3-C8 cycloalkyl, C4-C8 cycloalkenyl, C6-C 10 Aryl, C1-C 20 sulfides, -R 7 OR 7’ -R 7 (CO)R 7’ -R 7 (COO)R 7’ -R 7 (CONH)R 7’ -R 7 (NHCO)R 7’ -R 7 (NHCOO)R 7’ -R 7 (NHCONH)R 7’ -N=CR 7 R 7’ -N=CR 7’’ -C(O)R 7 The electrical conductivity of the heat transfer fluid is less than 100 µS / cm, preferably less than 50 µS / cm, more preferably less than 25 µS / cm, even more preferably less than 10 µS / cm, and most preferably less than 5 µS / cm; the heat transfer fluid contains a corrosion inhibitor.

2. The heat transfer fluid according to claim 1, wherein, The heat transfer fluid contains a base liquid consisting of water, alcohol, or a mixture thereof.

3. The heat transfer fluid according to claim 2, wherein, Water and alcohol are present in a weight ratio of 95:5 to 5:95 based on the total weight of the heat transfer fluid.

4. The heat transfer fluid according to any one of claims 2 or 3, wherein, The base liquid contains an alcohol, and wherein the alcohol is selected from the group consisting of: monoethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, hexaethylene glycol, monopropylene glycol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, pentapropylene glycol, hexapropylene glycol, methanol, ethanol, propanol, butanol, tetrahydrofurfuryl alcohol, ethoxylated furfuryl alcohol, dimethyl ether of glycerol, sorbitol, 1,2,6-hexanetriol, trimethylolpropane, methoxyethanol, glycerol, and combinations thereof.

5. The heat transfer fluid according to any one of claims 2 to 4, wherein, The weight ratio of the zwitterionic compound to the alcohol (based on the total weight of the heat transfer fluid) is between 1:250 and 1:2, preferably between 1:100 and 1:2, more preferably between 1:80 and 1:10, and most preferably between 1:50 and 1:

20.

6. The heat transfer fluid according to any one of the preceding claims, wherein, The composition comprises at least 0.1 wt.%, preferably at least 0.01 wt.%, more preferably at least 0.05 wt.%, more preferably at least 0.5 wt.%, and more preferably at least 1 wt.% of the zwitterionic compound based on the total weight of the heat transfer fluid.

7. The heat transfer fluid according to any one of the preceding claims, wherein, The weight ratio of the zwitterionic compound to the corrosion inhibitor (based on the total weight of the heat transfer fluid) is at least 5:1, preferably at least 10:1, and more preferably at least 15:

1.

8. The heat transfer fluid according to any one of the preceding claims, wherein, The zwitterionic compound is selected from zwitterionic compounds according to formula (Ia) or (Ib) and has a molecular weight of less than 1000 g / mol, preferably less than 500 g / mol, and more preferably less than 200 g / mol.

9. The heat transfer fluid according to any one of the preceding claims, wherein, The heat transfer fluid contains corrosion inhibitors selected from triazoles, thiazoles, triazines, diazoles, nonionic polymers, silicates, organosilicones, molecules containing trimethylsilyl groups, alcohols containing olefin or alkyne groups, and combinations thereof, preferably corrosion inhibitors selected from triazoles, thiazoles, triazines, diazoles, and combinations thereof.

10. The heat transfer fluid according to any one of the preceding claims, having a pH in the range of 3 to 10.

11. The heat transfer fluid according to any one of the preceding claims, wherein, The fluid further comprises one or more additives selected from the group consisting of antioxidants, anti-wear agents, surfactants, scale inhibitors, antifoaming agents, dyes, and combinations thereof, in an amount ranging from 0.001 to 10 wt.% (based on the total weight of the heat transfer fluid).

12. A method for exchanging heat, the method comprising the following steps: a. Providing a heat transfer fluid according to any one of claims 1 to 11; b. Providing a cooling system configured to bring the heat transfer fluid into thermal contact with an electrical system, the cooling system comprising an ion exchange resin; c. transferring heat from the electrical system to the heat transfer fluid; and d. bringing the heat transfer fluid into contact with the ion exchange resin.

13. The method according to claim 12, wherein, The volume ratio of the heat transfer fluid to the ion exchange resin is at least 1:99 v / v%, preferably at least 5:95 v / v%, more preferably at least 10:90 v / v%, and most preferably at least 20:80 v / v.

14. Use of a heat transfer fluid comprising a zwitterionic compound according to formula (Ia) or (Ib) as a heat transfer fluid in a cooling system comprising an ion exchange resin; wherein the heat transfer fluid has a conductivity at 25°C of less than 100 µS / cm, preferably less than 50 µS / cm, more preferably less than 25 µS / cm, more preferably less than 10 µS / cm, and most preferably less than 5 µS / cm.

15. The following uses of zwitterionic compounds according to formula (Ia) or (Ib): • for prolonging the corrosion inhibition properties of heat transfer fluids containing corrosion inhibitors when in contact with ion exchange resins, preferably when used as heat transfer fluids in cooling systems containing ion exchange resins in contact with the heat transfer fluids; • for prolonging the coloring or reducing the fading of heat transfer fluids containing dyes when in contact with ion exchange resins, preferably when used as heat transfer fluids in cooling systems containing ion exchange resins in contact with the heat transfer fluids; • for reducing the corrosion inhibition properties of heat transfer fluids used in the heat transfer fluids when in contact with ion exchange resins, preferably when used as heat transfer fluids in cooling systems containing ion exchange resins in contact with the heat transfer fluids. The amount of agent and / or dye; • For extending the service life of ion exchange resins by reducing or avoiding the uptake of heat transfer fluid components when in contact with a heat transfer fluid, preferably when the heat transfer fluid is used in a cooling system containing ion exchange resins in contact with the heat transfer fluid; • For extending the service life of heat transfer fluids containing corrosion inhibitors (and preferably alcohols as described herein) and / or ion exchange resins in contact with the heat transfer fluids by: ○ reducing, delaying or avoiding corrosion; ○ reducing, delaying or avoiding the formation of conductive acids such as glycolates; preferably when the heat transfer fluid is used in a cooling system containing ion exchange resins in contact with the heat transfer fluid.

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