Method for increasing the kinetic rate of a reaction, and related components and systems

Abstract

A method for increasing the kinetic rate of a reaction includes preparing a mixture that includes a reacting compound and a solution having a solvent compound and an ionic compound, and then heating the mixture to a temperature that is greater than the critical temperature of the solvent compound absent the reacting compound and the ionic compound, but less than the critical temperature of the mixture. The method also includes pressurizing the mixture to maintain a liquid phase of the solution while heating the mixture. Then, while the mixture is at the temperature, reacting the solution with the reacting compound in the mixture. With an ionic compound dissolved in the solvent compound, one can keep the solution of the solvent compound and ionic compound in the liquid phase while increasing the temperature of the mixture up beyond the critical point of the solvent compound alone. The higher temperature speeds up the reaction of the reacting compound with either the solvent compound and / or the solute compound depending on the specific reaction desired. In addition, the higher temperature may also increase the efficiency of the reaction of the reacting compound with either the solvent compound and / or the solute compound so that less solvent compound or less solute compound is required to provide the desired results of the reaction.

Description

METHOD FOR INCREASING THE KINETIC RATE OF A REACTION, AND RELATED COMPONENTS AND SYSTEMSSTATEMENT OF FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT[1] This invention was made with government support under Grant No. 2232969 awarded by the National Science Foundation. The government has certain rights in the invention.CROSS-REFERENCE TO RELATED APPLICATIONS AND INCORPORATION BY REFERENCE[2] This application claims priority from U.S. Provisional Patent Application 63 / 582,918 filed 15 September 2023 and titled “Hydrothermal Conversion In Hot Compressed Liquid Water With Amendment, And Related Systems And Methods”. This application also incorporates by this reference the entirety of this U.S. Provisional Patent Application.BACKGROUND[3] Widespread use of per- and polyfluoroalkyl substances (PFAS), which include a perfluoroalkyl and / or a polyfluoroalkyl (PFA) compound, in manufacturing processes, consumer goods, and firefighting foams has directly contributed to contamination of groundwater, soil, biosolids, and municipal drinking water supplies at concentrations significantly exceeding recommended exposure levels. In particular, the discharge of aqueous film-forming foams (AFFF) for firefighting training at military bases, airports, hydrocarbon storage facilities, and firefighter training centers has contributed to the water and soil contamination problem. Because PFAS are known carcinogens, even in the low parts per trillion (ppt) range, the federal and many state governments areregulating the use and existence of PFAS to reduce the amount of PFAS in drinking water and environmental discharge.[4] Many PFAS are perpetually stable in the environment because the C-F bond, which is the backbone of PFA compounds, is a very stable bond. PFAS-rich liquids from soil remediation, along with contaminated groundwater from firefighter training pits or wells, frequently require secondary treatment. Often, adsorbent media, such as granulated activated carbon (GAC) or ion exchange resins (IXR) are used to pull PFAS from contaminated water. GAC struggles to capture short-chain PFAS (such as perfluorobutanoic acid (PFBA)), which are less hydrophobic. Spent sorbents must eventually be disposed of in a landfill or incinerator, risking environmental recontamination. Alternatively, reverse osmosis (RO), foam fractionation, or regenerable sorbent systems do not produce any solid waste, but rather produce a more concentrated, PFAS-rich liquid waste which requires treatment and disposal.[5] Litigation and emerging regulations are driving a search for alternative end-of-life PFAS destruction technologies. PFAS destruction technologies must facilitate complete defluorination (cleaving all C-F bonds in a PFA compound) to eliminate the risk of subsequent environmental re-contamination, or future liability. Most PFAS destruction technologies are best suited for application on liquid wastes, with low treatment volumes and high PFAS concentrations.[6] Several technologies have been investigated as general PFAS destruction processes, including electrochemical oxidation over boron-doped diamonds, sonochemical destruction, high-temperature incineration, alkaline hydrolysis, plasma treatment, supercritical water oxidation, and others. However, few destructive technologies have robustly demonstrated the ability to consistently and completely break all C-F bonds in a PFA compound, and several are known to produce short-chain PFAS as a treatment product. While most of the aforementioned technologies have been demonstrated to destroy perflourooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), few have been demonstrated to achieve complete mineralization of all PFAS.[7] Alkaline Hydrolysis. Alkaline hydrolysis is an effective process for neutralizing or destroying several hazardous wastes, including chemical warfare agents (CWAs), polychlorinated biphenyls (PCBs), chlorinated solvents, all detectable PFAS molecules, and other substances. Alkaline hydrolysis occurs within the subcritical liquid phase of water (typically at temperatures between 100 - 374 °C, and at pressures between 0.1 - 50 MPa) amended with a suitable base, such as NaOH, KOH, LiOH, NH4OH and / or Ca(OH)2. Alkaline conditions promote decomposition mechanisms for many compounds and contaminants of interest. Alkaline hydrolysis is particularly advantageous for processing PFAS-contaminated liquids and / or solids because (i) salts remain fully soluble in the subcritical phase and do not cause issues with precipitation and scale buildup, (ii) the alkaline hydrolysis process can destroy PFAS and other contaminants with greater than 99.99% destruction efficiencies and without the production of unwanted byproducts, and (iii) alkaline hydrolysis is more energy efficient than incineration of liquid wastes, or other PFAS destruction processes.[8] Despite being greater than 99.99% effective for PFAS destruction, several factors hinder commercial development and deployment of alkaline hydrolysis. Required reaction times are long (more than 30 minutes), high alkaline concentrations are needed (around 5 mol / L of NaOH is typical) and high temperatures are needed (around 350 °C). Long reaction times necessitate the construction of large reactors, and the alkaline and high-temperature conditions promote corrosion of most materials, including specialty alloys. In addition, the alkaline and high-pressure environment promotes stress corrosion cracking due to the mechanical stress of the high-pressure environment.[9] Thus, there is a need for a more effective way to breakdown / destroy PFA compounds found in PFAS.SUMMARY

[0010] In one aspect of the invention, a method for increasing the kinetic rate of a reaction includes preparing a mixture that includes a reacting compound and a solution having a solvent compound and an ionic compound, and then heating the mixture to a temperature that is greater than the critical temperature of the solvent compound absent the reacting compound and the ionic compound, but less than the critical temperature of the mixture. The method also includes pressurizing the mixture to maintain a liquid phase of the solution while heating the mixture. Then, while the mixture is at the temperature, reacting the solution with the reacting compound in the mixture. Preparing the mixture may include adding an ionic compound to the solvent compound to introduce the ionic compound to the solvent compound, or to supplement the quantity of the ionic compound already present in the mixture. So, preparing the mixture may also include determining whether an ionic compound exists in the mixture, and, if so, then identifying the ionic compound and determining the quantity of the ionic compound in the mixture. Preparing the mixture may also include adding a solute compound to the solvent compound so that the reacting compound will react with the solute compound during the reacting step of the method.

[0011] With an ionic compound dissolved in the solvent compound, one can keep the solution of the solvent compound and ionic compound in the liquid phase while increasing the temperature of the mixture up beyond the critical point of the solvent compound alone. The higher temperature speeds up the reaction of the reacting compound with either the solvent compound and / or the solute compound depending on the specific reaction desired. In addition, the higher temperature may also increase the efficiency of the reaction of the reacting compound with either the solvent compound and / or the solute compound so that less solvent compound (if the reacting compound reacts with the solvent compound during the reacting step) or less solute compound (if the reacting compound reacts with the solute compound during the reacting step) is required to provide the desired results of the reaction. Thus, increasing the temperature at which a reaction occurs allows one to decrease the amount of time required to complete the reaction and obtain the desired product. And, increasing the temperatureat which a reaction occurs may also allow one to decrease the amount of solvent compound and / or solute compound required to obtain the desired product. For example, in an alkaline hydrolysis (AH) reaction used to break down the reacting compound trifluoromethanesulfonic acid (TFMS), an ultra-short-chain PFAS, water is the solvent compound and the amount of solute compound alkaline (NaOH) needed to destroy and defluorinate the TFMS at 350 °C is about 5 molar (M), and the amount of alkaline needed to destroy and defluorinate the same amount of TFMS at 400 °C is about 0.5 M. Less alkaline in the reaction mitigates the caustic and corrosive effect on the reaction vessel and other components of the reaction system that the reaction occurs in.

[0012] With an ionic compound dissolved in the solvent compound, one can also maintain a liquid phase of the solution while decreasing the pressure exerted on the mixture below the critical pressure of the solvent alone. This also has the effect of increasing the efficiency of the reaction of the reacting compound with either the solvent compound and / or the solute compound by increasing the concentration of the ionic compound in the liquid solution and / or the solute compound in the liquid solution, if present, by allowing some of the solvent to enter the vapor phase, much like distillation of alcohol from water.BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG. 1 shows a schematic view of a method for increasing the kinetic rate of a reaction, according to an embodiment of the invention.

[0014] FIG. 2 shows a phase diagram for pure water.

[0015] FIG. 3 shows three graphs illustrating destruction data and product yields for a reaction in which a PFAS, specifically trifluoromethanesulphonic acid (TFMS), is broken down via an AF reaction.

[0016] Each of FIGS. 4, 5, and 6 show destruction data and product yields for reactions in which a PFAS, specifically trifluoromethanesulphonic acid (TFMS), is broken down via AF reactions occurring at 350 °C, 380 °C, and 400 °C for about ten minutes with the addition of an ionic compound to a solution of water and sodium hydroxide, according to an embodiment of the invention.

[0017] FIG. 7 shows three graphs illustrating destruction data and product yields for a reaction in which a PFAS, specifically TFMS is broken down via AF reactions occurring at pressures above and below water’s critical pressure, according to an embodiment of the invention.DETAILED DESCRIPTION

[0018] FIG. 1 shows a schematic view of a method for increasing the kinetic rate of a reaction, according to an embodiment of the invention. Here, the method is used to increase the kinetic rate of an alkaline hydrolysis (AH) reaction for destroying and defluorinating PFAS; but the method may be used to increase the kinetic rate of many other, different reactions. For example, the method may be used to increase the rate of other hydrothermal reactions occurring in the liquid phase, including hydrothermal liquefaction (HTL) of sewage sludge, alkaline hydrolysis of other halogenated compounds (e.g., chlorinated solvents, brominated compounds), and hydrothermal gasification of wet organic wastes, such as biomass.

[0019] The method includes preparing a mixture that includes a reacting compound and a solution having a solvent compound and an ionic compound (See 10 in FIG. 1). Here, the reacting compound is PFAS; the solvent compound is water, and the ionic compound is salt (NaCI), although as discussed in greater detail below, the reacting compound, solvent compound and ionic compound may be compounds other than PFAS, water, and salt. The method also includes heating the mixture to a temperature that is greater than the critical temperature of the solvent compound absent the reacting compound and the ionic compound, but less than the critical temperature of the mixture(See 12 in FIG. 1). The method also includes pressurizing the mixture to maintain a liquid phase of the solution while heating the mixture to the temperature that is greater than the critical temperature of the solvent compound absent the reacting compound and the ionic compound, but less than the critical temperature of the mixture (See 14 in FIG. 1). Then, while the mixture is at the temperature, reacting the solution with the reacting compound in the mixture (See 16 in FIG. 1). Here, the temperature ranges from 374 °C to 900 °C and the pressure exerted on the mixture ranges from 10 Megapascals (MPa) to 50 MPa, although the temperature and pressure may be other temperatures and pressures commensurate with other solvent compounds and related solutions.

[0020] As discussed in greater detail below, preparing the mixture may include adding an ionic compound to the solvent compound to introduce the ionic compound to the solvent compound, or to supplement the quantity of the ionic compound already present in the mixture. So, preparing the mixture may also include determining whether an ionic compound exists in the mixture, and, if so, then identifying the ionic compound and determining the quantity of the ionic compound in the mixture. Preparing the mixture may also include adding a solute compound to the solvent compound so that the reacting compound will react with the solute compound during the reacting step of the method. Here, the solute compound is alkaline (NaOH), although as discussed in greater detail below, the solute compound may be any compound other than alkaline.

[0021] With the salt dissolved in the water, one can keep the solution of the water, alkaline and salt in the liquid phase while increasing the temperature of the mixture up beyond the critical point of water alone. The higher temperature speeds up the AH reaction. In addition, the higher temperature also increases the efficiency of the reaction of the PFAS with the alkaline so that less alkaline is required to destroy and defluorinate the PFAS. This, in turn, allows one to decrease the amount of time required to complete the AH reaction and obtain the desired breakdown of the PFAS. Increasing the temperature at which a reaction occurs also allows one to decrease the amount of alkaline required to obtain the desired breakdown of the PFAS.

[0022] With the salt dissolved in the water, one can also maintain a liquid phase of the solution of the water, alkaline, and salt while pressurizing the mixture to a pressure that is below the critical pressure of water alone. This also has the effect of increasing the efficiency of the reaction of the PFAS with the alkaline by increasing the concentration of the salt in the water by allowing some of the water to separate from the solution and enter the vapor phase; much like the distillation of alcohol from water.

[0023] Many chemical reactions are performed in the liquid state by dissolving one or more of the reactants or reacting compounds in a solvent because the reacting compounds are incompatible with each other in their respective natural states. For example, when reacting sodium (Na) or chlorine (Cl) with another compound, one can mix salt (NaCI) with the other compound; but because salt is a solid in its natural state on earth, salt is typically dissolved in water to separate the sodium element from the chlorine element to form sodium ions that are positively charged and chlorine ions that are negatively charged. In this manner, a reaction where sodium (or chlorine) is to combine with another compound, the sodium (or chlorine) ion is now free to combine with the other compound.

[0024] A common solvent for many different compounds is water (H2O) because the water molecule has a positive side or end where the hydrogen (H) atoms are concentrated around the oxygen atom, and a negative side or end, opposite the hydrogen atoms, where the oxygen (0) atom is more exposed. Because of this polarity, water is able to form hydrogen bonds with other polar elements and compounds, such as sodium ions and chlorine ions. Hydrogen bonding is similar to the attractive force generated by two oppositely charged particles, such as a proton and an electron. It is a relatively weak type of bond, but when many water molecules form a hydrogen bond with a single element or compound, the hydrogen bonding with the element or compound, can be strong enough to separate an ionic bond that holds the element or compound with another element or compound, such as the ionic bond that holds sodium and chlorine together to form salt. Although water is a common polar solvent, other compounds that have a negative end or side and positive end or side are also capable of dissolving compounds held together with ionic bonds.

[0025] Because many chemical reactions involve a liquid solvent for one or more of the reacting compounds there is limit to the temperature at which the reactions occur. As exemplified in FIG. 2 (a phase diagram for pure water), generally, as the pressure on liquid increases, the temperature at which the liquid changes to its vapor phase also increases. So, one could keep increasing the pressure experienced by the liquid solvent to increase the temperature at which the reaction can occur, and thus increase the kinetic rate of the reaction. There is, however, a limit to this. Once the liquid experiences its critical pressure (20 for water in FIG. 2), the solvent cannot exist in the liquid phase. It will either be in its vapor phase at temperatures below its critical temperature (22 for water in FIG. 2), or it will be in its supercritical phase at temperatures above its critical temperature. In the supercritical phase the solvent is liquid-like, but not a liquid; and vapor like, but not a vapor. In this supercritical phase, many of the solvent’s properties are very different than its properties as a liquid or as a vapor. Because of this the solvent’s ability to dissolve an ionic compound may be significantly reduced.

[0026] For example, the critical pressure 20 for water is 22.1 Megapascals (MPa) and the critical temperature 22 is 374 °C. In this pressure-temperature realm water’s physical properties are significantly different than its properties as a liquid. For example, liquid water at a pressure and temperature below its critical pressure 20 and temperature 22 is nearly incompressible, has a low thermal expansion coefficient, has a high dielectric constant, and is an excellent solvent for electrolytes. But, water at its critical point 24 becomes compressible, expandable, has a low dielectric constant, loses much of its ability to form hydrogen bonds with other elements and compounds, and mixes more readily with nonpolar gases and organic molecules. Thus, chemical reactions in which water is a solvent for one or more reacting compounds are limited to temperatures that do not cause water to become supercritical.

[0027] Referring back to FIG. 1 , having an ionic compound dissolved in a solvent compound, allows one to keep the solution of the solvent compound and ionic compound in the liquid phase while increasing the temperature of the mixture up beyond the critical temperature of the solvent compound alone. It may also allow one tomaintain a liquid phase of the solution while decreasing the pressure exerted on the mixture below the critical pressure of the solvent alone.

[0028] In this and other embodiments of the method, an alkaline hydrolysis (AH) reaction is used to destroy and defluorinate PFAS and begins with preparing a mixture that includes a reacting compound and a solution having a solvent compound, an ionic compound, and a solute compound. In this AH reaction, the mixture includes PFAS as the reacting compound, water as the solvent compound, table salt (NaCI) as the ionic compound, and alkaline (NaOH) as the solute compound. Because hydroxides are also ionic compounds, in some AH reactions additional alkaline may be added to the mixture to increase the temperature at which the solution will remain a liquid during the reaction. This, however, may not be beneficial unless the hydroxides’ caustic and corrosive effects may be ignored or are insignificant. Sometimes, the PFAS to be treated by the alkaline hydrolysis (AH) reaction is already mixed in with an aqueous solution of a salt. Sometimes the PFAS to be treated by the AH reaction is suspended in water alone. Because of this variety in the constituents of the reaction, the first step 10 of preparing the mixture may include determining whether salt or some other ionic compound exists in the mixture, and, if so, identifying the ionic compound and determining the quantity of the ionic compound in the mixture. The process for determining the presence of an ionic compound in the mixture, and for identifying the ionic compound and its quantity may be any desired process that will provide desired information. After this is done, preparing the mixture may include adding salt to the solvent compound if the mixture does not already contain the desired amount of salt. In situations where the mixture does not contain any of the desired salt for the reaction, then salt may be added to introduce the salt into the mixture to be dissolved by the water. In situations where the mixture does already contain a quantity of the desired salt for the reaction, then salt may be added to supplement the existing quantity of salt dissolved by the water.

[0029] Other embodiments of the method are possible. For example, ionic compounds other than salt (NaCI) may be added to the mixture as a supplement to or in lieu of salt, such as potassium chloride (KCI), calcium chloride (CaCl2), potassium hydroxide (KOH), and ammonium hydroxide (NH4OH). As another example of other possibleembodiments, solute compounds other than alkaline (NaOH) may be added to the mixture as a supplement to or in lieu of alkaline, such as potassium hydroxide (KOH), ammonium hydroxide (NH4OH), lithium hydroxide (LiOH), and calcium hydroxide (Ca(0H)2). As yet another example of other possible embodiments, reacting compounds other than PFAS may be included in the mixture in addition to or in lieu of PFAS, such as halogenated organic compounds, refrigerants (HFC), chemical warfare agents, polychlorinated biphenyls (PCBs), and chlorinated solvents such as tetrachloroethene (PCE), and trichloroethene or trichloroethylene (TCE). And as yet another example of other possible embodiments, solvent compounds other than water may be included in the mixture, such as methanol (MeOH, or CH3OH), other alcohols, acetone, and toluene.

[0030] The quantity of the ionic compound in the mixture before heating the mixture may be any desired quantity to provide the desired concentration that will maintain the liquid phase of the solution at the elevated temperature that the reaction will be performed at. For example, in this and other embodiments the quantity of salt in the mixture before heating the mixture is a quantity that when dissolved by the water provides a salt concentration in the water that is greater than one percent by weight. More specifically, the quantity of salt in the mixture before heating the mixture is a quantity that provides a salt concentration in the water that is between five percent and fifty percent by weight.

[0031] Still referring to FIG. 1, the method also includes heating the mixture to a temperature that is greater than the critical temperature of the solvent compound absent the reacting compound, the ionic compound, and solute compound (if present), but less than the critical temperature of the mixture. Heating the mixture may be done in any desired way capable of heating the mixture to the desired temperature, which is often very, very hot, and maintaining the desired temperature during the reaction. In this and other embodiments the mixture is heated to a temperature that is at least 374 °C. More specifically, the mixture is heated to a temperature between 374 °C and 900 °C.

[0032] Still referring to FIG. 1, the method also includes pressurizing the mixture to maintain a liquid phase of the solution while heating the mixture to the temperature that is greater than the critical temperature of the solvent compound absent the reactingcompound, the ionic compound, and the solute compound (if present), but less than the critical temperature of the mixture. Pressurizing the mixture may be done in any desired way capable of generating and maintaining the desired pressure that maintains the solution in a liquid phase. In this and other embodiments, the pressure that the mixture experiences is between 10 Megapascals (MPa) and 50 MPa. More specifically, the mixture experiences a pressure of 22.1 MPa, which is the critical pressure of pure water. At this pressure, much of the water in the solution remains in the liquid phase while the temperature of the mixture reaches a temperature greater than water’s critical temperature. In other embodiments discussed in greater detail in conjunction with FIG. 5, the pressure experienced by the mixture may be less than the critical pressure of water alone. In this situation, water in the solution will change its phase to vapor and boil out of the solution. Over time, most of if not all of the water will boil out of the solution. So, an advantage to pressurizing the mixture to water’s critical pressure is that the duration of the reaction will not be limited by the time it takes to boil out the water in the solution at a lower pressure.

[0033] Each of FIGS. 3, 4, 5, and 6 shows three graphs illustrating destruction data and product yields for a reaction in which a PFAS, specifically trifluoromethanesulphonic acid (TFMS) is broken down via an AH reaction. FIG. 3 shows destruction data and product yields for a reaction occurring at 350 °C for about ten minutes without the addition of an ionic compound to a solution of water and sodium hydroxide. FIGS. 4, 5, and 6 show destruction data and product yields for reactions occurring at 350 °C, 380 °C, and 400 °C for about ten minutes with a solution of water, sodium hydroxide, and an ionic compound, according to an embodiment of the invention.

[0034] In these examples of reactions, feedstocks containing mixtures of deionized (DI) water, trifluoromethanesulfonic acid (TFMS), sodium hydroxide (NaOH) and / or sodium chloride (NaCI) were prepared with various concentrations of NaOH and NaCI. Each of the resulting mixtures was subjected to high-temperature, high-pressure, liquid water conditions in a continuous-flow water reactor. Residence times in the water reactor varied slightly with changes in the density of the mixture at the given temperature and pressure. Samples were collected before and after processing for analysis with afluoride ion selective electrode (ISE) to quantify dissolved fluoride levels, and with a Raman spectroscopic ball probe to quantify TFMS, carbonate, bicarbonate, formate, and sulfate concentrations in the mixtures before the reactions and after the reactions.

[0035] Analysis of the product yields shows reacting conditions where reactions occur much faster and / or more completely. Results from TFMS destruction experiments in an alkaline hydrothermal environment show that a final stable product of fluoride, sulfate, carbonate, and formate formed in each of the reactions. As shown in FIG. 3, the reaction at 350 °C with 5 M-NaOH resulted in greater than 95% TFMS destruction and stoichiometric fluoride yield. And as shown in FIG. 6, the reaction at 400 °C with 3%wt NaCI and about 1.0 M-NaOH running for about ten minutes resulted in a similar level of TFMS destruction and defluorination (greater than 95%) validating that higher salt content allows for achieving similar reaction outcomes with higher temperatures and much lower NaOH concentrations. Other experiments conducted at 350 °C appeared to show that NaCI addition increased TFMS destruction and defluorination.

[0036] FIG. 7 shows three graphs illustrating destruction data and product yields for a reaction in which a PFAS, specifically TFMS, is broken down via AH reactions occurring at pressures above and below water’s critical pressure, according to an embodiment of the invention. In this example, feedstocks containing mixtures of deionized (DI) water, TFMS, and sodium hydroxide (NaOH) at a concentration of 0.5 M were prepared. Each of the resulting mixtures was subjected to 400 °C, and either 20 Megapascals (MPa) (2900 psi), which is less than the critical pressure of pure water, or 24.8 MPa (3,600 psi), which is greater than the critical pressure of pure water. Residence times in the water reactor were the same for both reactions. As shown in FIG. 7, both reactions destroyed the TFMS molecule, but the reaction at 20 MPa provided a more complete defluorination from all intermediary compounds and / or by-product compounds of the reaction. Thus, more of the fluorine originally bound in the TFMS was isolated into fluoride (F_).

[0037] The preceding discussion is presented to enable a person skilled in the art to make and use the invention. Various modifications to the embodiments will be readily apparent to those skilled in the art, and the generic principles herein may be applied toother embodiments and applications without departing from the spirit and scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.

Claims

What is claimed is:1 . A method for increasing the kinetic rate of a reaction, the method comprising: preparing a mixture that includes a reacting compound and a solution having a solvent compound and an ionic compound; heating the mixture to a temperature that is greater than the critical temperature of the solvent compound absent the reacting compound and the ionic compound, but less than the critical temperature of the mixture; pressurizing the mixture to maintain a liquid phase of the solution while heating the mixture to the temperature that is greater than the critical temperature of the solvent compound absent the reacting compound and the ionic compound, but less than the critical temperature of the mixture. reacting the solution with the reacting compound in the mixture while the temperature of the mixture is greater than the critical temperature of the solvent compound absent the reacting compound and the ionic compound.

2. The method of claim 1 wherein preparing the mixture includes adding the ionic compound to the solvent compound.

3. The method of claim 1 wherein preparing the mixture includes determining whether an ionic compound exists in the mixture, and: if an ionic compound does exist, then identifying the ionic compound and determining the quantity of the ionic compound in the mixture, and if an ionic compound does not exist, then adding an ionic compound to the mixture.

4. The method of claim 1 wherein preparing the mixture includes adding a solute compound to the solvent compound.

5. The method of claim 1 wherein preparing the mixture includes adding a solute compound and the ionic compound to the solvent compound.

6. The method of claim 1 wherein preparing the mixture includes dissolving the ionic compound in the solvent compound.

7. The method of claim 1 wherein preparing the mixture includes: adding the ionic compound and a solute compound to the solvent compound; and dissolving the ionic compound and the solute compound in the solvent compound.

8. The method of claim 1 wherein the reaction is a hydrothermal reaction.

9. The method of claim 1 wherein the reacting compound includes a halogenated organic compound.

10. The method of claim 1 wherein the reacting compound includes a PFAS compound.11 . The method of claim 4 wherein the solute compound includes at least one of the following bases: sodium hydroxide (NaOH), potassium hydroxide (KOH), ammonium hydroxide (NH4OH), lithium hydroxide (LiOH), calcium hydroxide (Ca(OH)2), magnesium hydroxide (Mg(OH)2), sodium carbonate (Na2CO3), potassium carbonate (K2CO3), and lithium carbonate (Li2CO3).

12. The method of claim 2 wherein adding an ionic compound includes adding at least one of the following compounds: sodium chloride (NaCI), potassium chloride (KCI), sodium hydroxide (NaOH), potassium hydroxide (KOH), ammonium hydroxide (NH4OH), lithium hydroxide (LiOH), calcium hydroxide (Ca(OH)2), magnesium hydroxide (Mg(OH)2), sodium carbonate (Na2CO3), potassium carbonate (Na2CO3), lithium carbonate (Li2CO3), sodium sulfate (Na2SO4), sodium nitrate (NaNOs), sodium fluoride (NaF), potassium sulfate (K2SO4), potassium nitrate (KNO3), potassium fluoride (KF), lithium sulfate (U2SO4), lithium nitrate (LiNOs), lithium fluoride (LiF), and lithium chloride (LiCI)13. The method of claim 7 wherein adding an ionic compound includes adding a quantity to generate a concentration of the dissolved ionic compound that is greater than one percent by weight.

14. The method of claim 7 wherein adding an ionic compound includes adding a quantity to generate a concentration of the dissolved ionic compound that is between five percent by weight and fifty percent by weight.

15. The method of claim 7 wherein dissolving the ionic compound in the solvent compound includes separating the elements of the ionic compound from each other.

16. The method of claim 1 wherein heating the mixture to a temperature includes heating the mixture to a temperature that is at least 374 °C.

17. The method of claim 1 wherein heating the mixture to a temperature includes heating the mixture to a temperature that is at least 374 °C and less than 900 °C.

18. The method of claim 1 wherein pressurizing the mixture includes pressurizing the mixture to a pressure that is greater than the critical pressure of the solvent compound absent the reacting compound and the ionic compound, but less than the critical pressure of the mixture.

19. The method of claim 1 wherein pressurizing the mixture includes pressurizing the mixture to a pressure that is less than the critical pressure of the solvent compound absent the reacting compound and the ionic compound, to allow some of the solvent to enter the vapor phase while keeping the solution in the liquid phase.

20. The method of claim 1 wherein pressurizing the mixture includes pressurizing the mixture to a pressure greater than 22.1 Megapascals (MPa).21 . The method of claim 1 wherein pressurizing the mixture includes pressurizing the mixture to a pressure between 2 Megapascals (MPa) and 50 MPa.

2. The method of claim 1 : wherein the reaction is an alkaline hydrolysis (AH) reaction, the reacting compound is a PFAS compound and: preparing the mixture includes: adding a solute compound that is alkaline (NaOH) to the solvent compound that is water, and an ionic compound that is sodium chloride (NaCI) to the water in a quantity to generate a concentration of the ionic compound that is between five percent by weight and twenty-five percent by weight, and dissolving the NaCI and the NaOH in the solvent compound; heating the mixture to a temperature includes heating the mixture to temperature that is at least 374 °C and less than 500 °C; pressurizing the mixture to a pressure includes pressurizing the mixture to a pressure that is between 10 Megapascals (MPa) and 50 MPa, while heating the mixture; and reacting the PFAS compound with the solution of NaCI, alkaline, and water.

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