Processes for producing high-purity trifluoroiodomethane

Abstract

To provide a method for purifying trifluoroiodomethane.SOLUTION: A method includes: providing a process stream comprising trifluoroiodomethane, organic impurities, and acid impurities; reacting the process stream with a basic aqueous solution, the basic aqueous solution comprising water and at least one base selected from the group consisting of an alkali metal carbonate and an alkali metal hydroxide; and separating at least some of the organic impurities from the process stream.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a process for producing high purity trifluoroiodomethane (CF3I). Specifically, the present disclosure relates to a process for purifying trifluoroiodomethane to provide a high yield of high purity trifluoroiodomethane. [Background technology]

[0002] Trifluoroiodomethane (CF3I), also known as perfluoromethyl iodide, trifluoromethyl iodide, or iodotrifluoromethane, is a compound useful in commercial applications, for example, as a refrigerant or fire suppressant. CF3I is a low global warming potential molecule with a near-zero ozone depletion potential. CF3I can replace more environmentally harmful materials.

[0003] Several known processes exist for producing CF3I and compositions containing CF3I. Many of these processes involve the direct catalytic iodation of suitable precursor compounds containing CF3 group moieties. In many of these processes, the crude process stream containing CF3I may also contain organic impurities, acid impurities, and water. Organic impurities can include, for example, fluorinated and iodinated hydrocarbons such as pentafluoroethane (HFC-125), hexafluoropropene (HFO-1216), 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea), 1,1,3,3,3-pentafluoropropene (HFO-1225zc), 1,1,1,3,3,3-hexafluoropropane (HFC-236fa), and / or methyl iodide (CHI). Organic impurities can also include carbon dioxide (CO2). Organic impurities may be formed as by-products during the production of CF3I and / or may be present in the reactants or other starting materials used to produce CF3I.

[0004] According to the U.S. Department of Agriculture, CH3I has moderate to high acute toxicity when inhaled and ingested. Toxicity assessments specify that high-purity CF3I must contain less than 5 ppm CH3I. Concentrations of CH3I in crude process streams can typically be about 1,000 ppm and may be as high as 5,000 ppm.

[0005] Acid impurities include, for example, hydrogen fluoride (HF), hydrogen chloride (HCl), hydrogen iodide (HI), and / or trimethylsilyl iodide. Examples of impurities include trifluoroacetic acid (TFA). Acid impurities may be formed as by-products during the production of CF3I and / or may be present in the reactants or other starting materials used to produce CF3I. The concentration of acid impurities in the crude process stream may range from about 20 ppm to about 100 ppm. Water may also be present in the reactants or other starting materials used to produce CF3I. The concentration of water in the crude process stream may range from about 5 ppm to about 100 ppm. The presence of acid impurities and water in the crude process stream creates a corrosive medium that can have detrimental effects on downstream processing equipment, such as distillation columns, pumps, piping, sensors, and storage tanks. Corrosion, which can lead to equipment replacement and / or repair, can reduce the overall efficiency of the purification process. High-purity CF3I requires acid impurities of 1 ppm or less and water of 10 ppm or less.

[0006] Therefore, a purification process is needed that sufficiently removes organic impurities (especially CH3I), acid impurities, and water to produce high-purity CF3I. Summary of the Invention

[0007] The present disclosure provides a process for purifying trifluoroiodomethane (CF3I) to provide high yields of high purity trifluoroiodomethane.

[0008] In one aspect, the present disclosure provides a method for purifying trifluoroiodomethane, the method including providing a process stream containing trifluoroiodomethane, organic impurities, and acid impurities, reacting the process stream with an aqueous basic solution comprising water and at least one base selected from the group of alkali metal carbonates and alkali metal hydroxides, and separating at least a portion of the organic impurities from the process stream.

[0009] In the reaction step, the at least one base may be an alkali metal carbonate. The concentration of the alkali metal carbonate in the basic aqueous solution may be about 0.01% by weight to about 20% by weight. The concentration of the alkali metal carbonate in the basic aqueous solution may be about 0.5% by weight to about 5% by weight. The alkali metal carbonate may be sodium carbonate.

[0010] The at least one base may include an alkali metal hydroxide. The concentration of the alkali metal hydroxide in the basic aqueous solution may be about 0.01% by weight to about 20% by weight. The concentration of the alkali metal hydroxide in the basic aqueous solution may be about 0.5% by weight to about 1% by weight. The alkali metal hydroxide may include potassium hydroxide.

[0011] In the reaction step, the temperature of the process stream can be from about 5° C. to about 80° C., and the pressure of the process stream can be from about 1 psig to about 100 psig.

[0012] An example of an organic impurity in the providing step is methyl iodide. The reaction step can reduce the concentration of methyl iodide in the process stream by about 1% to about 70% of all organic compounds in terms of GC area %. The reaction step may precede the separation step. The reaction step may follow the separation step.

[0013] The method may further include an additional drying step immediately after the reacting step to remove at least a portion of the water from the process stream. The process stream after the reacting, drying, and separating steps may contain at least about 99% by weight trifluoroiodomethane, less than about 50 ppm methyl iodide, less than about 100 ppm water, and less than about 20 ppm acid impurities. The method may be a continuous process.

[0014] In another of its aspects, the present disclosure provides a method for purifying trifluoroiodomethane, the method including providing a process stream containing trifluoroiodomethane, organic impurities, and acid impurities, contacting the process stream with an acid reactant, and separating at least a portion of the organic impurities from the process stream.

[0015] The acid reactant may be an alumina adsorbent. In the contacting step, the process stream may be in a liquid phase, the temperature of the process stream may be about -50°C to about 50°C, and the pressure of the process stream may be about 1 psig to about 100 psig. In the contacting step, the process stream may be in a gas phase, the temperature of the process stream may be about -20°C to about 60°C, and the pressure of the process stream may be about 1 psig to about 100 psig.

[0016] The contacting step may precede the separating step. The contacting step may follow the separating step.

[0017] The method may further include an additional drying step immediately after the contacting step to remove at least a portion of the water from the process stream. The process stream after the contacting, drying, and separating steps may contain at least about 99 wt% trifluoroiodomethane, less than about 50 ppm methyl iodide, less than about 100 ppm water, and less than about 20 ppm acid impurities.

[0018] The above and other features of the present disclosure, and the manner in which they are achieved, will become more apparent and be better understood by referring to the following description of the embodiments in light of the accompanying drawings. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a process flow diagram showing a process for producing high purity trifluoroiodomethane.

[0020] [Figure 2] FIG. 1 is a process flow diagram showing another process for producing high purity trifluoroiodomethane.

[0021] [Figure 3] FIG. 1 is a process flow diagram showing another process for producing high purity trifluoroiodomethane.

[0022] [Figure 4] FIG. 1 is a process flow diagram showing another process for producing high purity trifluoroiodomethane. DETAILED DESCRIPTION OF THE INVENTION

[0023] The present disclosure provides a process for purifying crude trifluoroiodomethane (CF3I) to provide high yields of CF3I. Neutralization of acid from process streams containing CF3I has been found to be particularly difficult because CF3I can be chemically decomposed when contacted with basic solutions typically used to neutralize acid, resulting in loss of CF3I product.

[0024] Acid impurities can be removed from a process stream by passing the stream through a scrubber containing an aqueous basic solution. It has been found that acid impurities in a process stream can be effectively removed without significantly decomposing the CF3I by passing a crude process stream containing CF3I and acid impurities through a scrubber containing an aqueous basic solution comprising water and at least one base in a defined concentration range. The base can be an alkali metal carbonate and / or an alkali metal hydroxide.

[0025] The basic aqueous solution may consist essentially of water and at least one base. The basic aqueous solution may consist of water and at least one base.

[0026] The base may comprise an alkali metal hydroxide. The base may consist essentially of an alkali metal hydroxide. The base may consist of an alkali metal hydroxide. The alkali metal hydroxide may be selected from the group consisting of sodium hydroxide (NaOH), potassium hydroxide (KOH), and lithium hydroxide (LiOH), and combinations thereof. Preferably, the alkali metal hydroxide may comprise potassium hydroxide. More preferably, the alkali metal hydroxide may consist essentially of potassium hydroxide. Most preferably, the alkali metal hydroxide may consist of potassium hydroxide. The alkali metal hydroxide may consist essentially of sodium hydroxide. The alkali metal hydroxide may consist of sodium hydroxide. The alkali metal hydroxide may consist essentially of lithium hydroxide. The alkali metal hydroxide may consist of lithium hydroxide.

[0027] The crude process stream may also contain organic impurities. It has been found that an aqueous basic solution, where the base comprises an alkali metal hydroxide, can also remove a significant proportion of the organic impurity, CH3I. CH3I in the process stream may react with the alkali metal hydroxide in the aqueous basic solution in the scrubber to form methanol and an alkali iodide salt according to Equation 1 below: Equation 1: CH3I+XOH→CH3OH+XI, where XI is potassium iodide, sodium iodide, or lithium iodide. Methanol and alkali iodide salts are readily soluble in aqueous basic solutions and are therefore easily removed from process streams.

[0028] CH3I has been found to undergo this reaction in Equation 1 more readily than CF3I. Without wishing to be bound by any theory, it is believed that the difference in reactivity is due, at least in part, to the significantly better solubility of CH3I in water than that of CF3I.

[0029] The composition of organic compounds in a process stream can be determined by gas chromatography (GC) analysis and gas chromatography-mass spectroscopy (GC-MS) analysis. The graphical areas provided by the GC analysis for each of the organic compounds can be combined to provide the GC area percentage (GC area%) of total organic compounds for each of the organic compounds as a measure of the relative concentration of the organic compounds in the process stream.

[0030] The concentration of CHI in the process stream, as a GC area % of total organic compounds, can be reduced by the reaction step, where the basic aqueous solution includes an alkali metal hydroxide in an amount as little as about 1%, about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, or about 35%, or as much as about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, or about 80%, or within any range defined between any two of the foregoing values, such as, for example, about 1% to about 80%, about 5% to about 70%, about 10% to about 65%, about 15% to about 60%, about 20% to about 55%, about 25% to about 50%, about 30% to about 45%, or about 35% to about 40%. Preferably, the concentration of CHI in the process stream can be reduced by the reaction step by about 1% to about 70%. More preferably, the concentration of CH3I in the process stream can be reduced by about 5% to about 50% by the reaction step. Most preferably, the concentration of CH3I in the process stream can be reduced by about 5% to about 30% by the reaction step.

[0031] While CH3I can be effectively removed from the process stream by distillation, as described below, removing a significant amount of CH3I with an aqueous base solution prior to distillation can allow the distillation column to operate more efficiently. CH3I may represent the largest constituent of organic impurities in the process stream. By removing a significant portion of the organic impurities prior to the distillation column, the flow rate of the process stream through the distillation column can be increased, increasing the rate at which high-purity CF3I can be produced. Alternatively, or in addition, reducing the organic impurities prior to the distillation column can allow a smaller distillation column to be used to achieve the desired production rate of high-purity CF3I.

[0032] Removing a significant amount of CH3I with aqueous base after distillation also allows the distillation column to operate more efficiently, since it would not be necessary to operate the column to produce as pure CF3I as ultimately required. By removing a significant portion of the organic impurities after distillation, fewer organic impurities need to be removed. Therefore, the flow rate of the process stream through the distillation column can be increased. Alternatively, or in addition, reducing the organic impurities after the distillation column can allow a smaller distillation column to be used to achieve the desired production rate of high purity CF3I.

[0033] It has also been found that at higher concentrations of alkali metal hydroxide, CF3I can react with alkali metal hydroxide in the basic aqueous solution in the scrubber and decompose to form carbonyl fluoride, alkali fluorides, alkali iodides, and water according to the following equation 2: Equation 2: CF3I+2XOH→CF2O+XI+XF+H2O where XI is potassium iodide, sodium iodide, or lithium iodide, and XF is potassium fluoride, sodium fluoride, or lithium fluoride. Therefore, the concentration of alkali metal hydroxide in the basic aqueous solution must be strictly controlled to limit the decomposition of this CF3I and maintain the yield of CF3I in the purification process.

[0034] The concentration of the alkali metal hydroxide as a percentage of the total weight of the basic aqueous solution can be as little as about 0.01 weight percent (wt%), about 0.02 wt%, about 0.05 wt%, about 0.1 wt%, about 0.2 wt%, about 0.5 wt%, or about 1 wt%, or as much as about 2 wt%, about 5 wt%, about 10 wt%, about 15 wt%, or about 20 wt%, or, for example, from about 0.01 wt% to about 20 wt%. The alkali metal hydroxide concentration may be within any range defined between any two of the aforementioned values, such as about 0.02% by weight to about 15% by weight, about 0.05% by weight to about 12% by weight, about 0.1% by weight to about 10% by weight, about 0.2% by weight to about 5% by weight, about 0.5% by weight to about 2% by weight, about 0.5% by weight to about 5% by weight, about 0.05% by weight to about 1% by weight, about 0.5% by weight to about 1% by weight, or about 0.1% by weight to about 5% by weight. Preferably, the alkali metal hydroxide concentration may be about 0.1% by weight to about 5% by weight. More preferably, the alkali metal hydroxide concentration may be about 0.5% by weight to about 1% by weight. Most preferably, the alkali metal hydroxide concentration may be about 0.5% by weight.

[0035] It has also been found that aqueous basic solutions in which the base comprises an alkali metal carbonate do not remove a significant proportion of the organic impurity CH3I, but also cause less significant decomposition of CF3I. Therefore, as described below, it may be preferable to use an aqueous basic solution in which the base comprises an alkali metal carbonate rather than an alkali metal hydroxide to retain more of the CF3I and rely solely on a separation process to remove CH3I from the process stream.

[0036] The base may include an alkali metal carbonate. The base may consist essentially of an alkali metal carbonate. The base may consist of an alkali metal carbonate. The alkali metal carbonate may be selected from the group consisting of sodium carbonate (Na2CO3), potassium carbonate (K2CO3), and lithium carbonate (Li2CO3), and combinations thereof. Preferably, the alkali metal carbonate may include sodium carbonate. More preferably, the alkali metal carbonate may consist essentially of sodium carbonate. Most preferably, the alkali metal carbonate may consist of sodium carbonate. The alkali metal carbonate may consist essentially of potassium carbonate. The alkali metal carbonate may consist of potassium carbonate. The alkali metal carbonate may consist essentially of lithium carbonate. The alkali metal carbonate may consist of lithium carbonate.

[0037] The concentration of the alkali metal carbonate as a percentage of the total weight of the basic aqueous solution can be as little as about 0.01 weight percent (wt%), about 0.02 wt%, about 0.05 wt%, about 0.1 wt%, about 0.2 wt%, about 0.5 wt%, or about 1 wt%, or as much as about 2 wt%, about 5 wt%, about 10 wt%, about 15 wt%, or about 20 wt%, or any of the foregoing values, such as, for example, about 0.01 wt% to about 20 wt%, about 0.02 wt% to about 15 wt%, about 0.05 wt% to about 12 wt%, about 0.1 wt% to about 10 wt%, about 0.2 wt% to about 5 wt%, about 0.5 wt% to about 2 wt%, or about 0.5 wt% to about 5 wt%. The concentration of the alkali metal carbonate may be within any range defined between any two of these. Preferably, the concentration of the alkali metal carbonate may be from about 0.1% by weight to about 10% by weight. More preferably, the concentration of the alkali metal carbonate may be from about 0.5% by weight to about 5% by weight. Most preferably, the concentration of the alkali metal carbonate may be about 5% by weight.

[0038] The contact time between the process stream and the aqueous basic solution is not particularly critical and can be as short as 0.5 seconds. Contact times can be much longer and still not cause significant decomposition of CF3I.

[0039] The process stream may be in the gas or liquid phase as it passes through the scrubber. The pressure and temperature of the process stream passing through the scrubber should be tightly controlled to limit undesirable secondary reactions involving CF3I.

[0040] When passing through the scrubber, the process stream may be at a temperature as low as about 5°C, about 10°C, about 15°C, about 20°C, about 25°C, or about 30°C, or as high as about 40°C, about 50°C, about 60°C, about 70°C, or about 80°C, or any temperature within any range defined between any two of the foregoing values, such as, for example, about 5°C to about 80°C, about 10°C to about 70°C, about 15°C to about 60°C, about 20°C to about 50°C, about 25°C to about 40°C, or about 20°C to about 40°C. Preferably, the process stream temperature in the scrubber may be from about 10°C to about 50°C. More preferably, the process stream temperature in the scrubber may be from about 20°C to about 40°C.

[0041] When passing through the scrubber, the process stream may be at a pressure as low as about 1 psig, about 2 psig, about 3 psig, about 5 psig, about 10 psig, about 20 psig, about 25 psig, or about 30 psig, or as high as about 40 psig, about 50 psig, about 60 psig, about 70 psig, about 80 psig, about 90 psig, or about 100 psig, or any pressure within any range defined between any two of the foregoing values, such as, for example, about 1 psig to about 100 psig, about 2 psig to about 90 psig, about 3 psig to about 80 psig, about 5 psig to about 70 psig, about 5 psig to about 60 psig, about 5 psig to about 50 psig, about 5 psig to about 40 psig, or about 5 psig to about 50 psig. Preferably, the process stream pressure in the scrubber may be from about 3 psig to about 80 psig. More preferably, the process stream pressure in the scrubber can be from about 5 psig to about 50 psig.

[0042] Alternatively, or in addition, acid impurities can be removed from the process stream by passing the process stream through an adsorption tower containing an acid activator, which is a material that adsorbs acid.

[0043] The acid activator can include at least one adsorbent selected from the group consisting of alumina, alkali metal oxides, alkaline earth metal oxides, metal hydroxides, aluminosilicate minerals, zirconia, and silica. The acid activator can be an adsorbent selected from the group consisting of alumina, alkali metal oxides, alkaline earth metal oxides, metal hydroxides, aluminosilicate minerals, zirconia, silica, and combinations thereof.

[0044] It has been discovered that acid impurities in a process stream containing CF3I can be effectively removed without significantly reducing the yield of CF3I by passing the process stream through an adsorption tower containing an acid activator that does not initiate or favor the decomposition of CF3I.

[0045] The acid activator may comprise alumina. The acid activator may consist essentially of alumina. The activator may comprise alumina, which may include one or more types of alumina, such as P-188 or P-188 available from UOP LLC (Des Plaines, IL). CLR-204, or HF-200XP from BASF (Iselin, NJ), or Alfa Activated alumina, such as aluminum oxide catalyst supports from Aesar (Haverhill, MA) It could be.

[0046] The contact time between the process stream and the adsorption tower containing the acid activator is not particularly critical and can be as short as 0.5 seconds. The contact time can be much longer and still not cause significant decomposition of CF3I.

[0047] The process stream may be in the vapor or liquid phase as it passes through the adsorption tower containing the acid activator.

[0048] When passing through the adsorption tower in the liquid phase, the process stream can be at a temperature as low as about −50° C., about −45° C., about −40° C., about −35° C., about −30° C., about −25° C., about −20° C., or about −15° C., or as high as about −10° C., about −5° C., about 0° C., about 5° C., about 10° C., about 15° C., about 20° C., about 25° C., about 30° C., about 35° C., about 40° C., about 45° C., or about 50° C., or any temperature within any range defined between any two of the foregoing values, such as, for example, about −50° C. to about 50° C., about −40° C. to about 45° C., about −30° C. to about 40° C., about −25° C. to about 35° C., about −10° C. to about 30° C., or about 0° C. to about −25° C. Preferably, the process stream temperature in the adsorption tower can be from about 0° C. to about 35° C. More preferably, the process stream temperature in the adsorption tower can be from about 10°C to about 30°C.

[0049] When passing through the adsorption tower in the liquid phase, the process stream can be at a pressure as low as about 1 psig, about 5 psig, about 10 psig, about 20 psig, about 25 psig, or about 30 psig, or as high as about 40 psig, about 50 psig, about 60 psig, about 70 psig, about 80 psig, about 90 psig, or about 100 psig, or any pressure within any range defined between any two of the foregoing values, such as, for example, about 1 psig to about 100 psig, about 5 psig to about 90 psig, about 10 psig to about 80 psig, about 15 psig to about 70 psig, about 20 psig to about 60 psig, about 25 psig to about 50 psig, about 30 psig to about 40 psig, or about 20 psig to about 50 psig. Preferably, the process stream pressure in the adsorption tower can be from about 10 psig to about 90 psig. More preferably, the process stream pressure in the adsorption tower can be from about 20 psig to about 50 psig.

[0050] When passing through the adsorption tower in the vapor phase, the process stream can be at a temperature as low as about −20° C., about −15° C., about −10° C., about −5° C., about 0° C., about 5° C., about 10° C., or about 15° C., or as high as about 20° C., about 25° C., about 30° C., about 35° C., about 40° C., about 45° C., about 50° C., about 55° C., or about 60° C., or any temperature within any range defined between any two of the foregoing values, e.g., about −20° C. to about 60° C., about −10° C. to about 50° C., about 0° C. to about 40° C., about 10° C. to about 30° C., about −5° C. to about 50° C., or about 15° C. to about 40° C. Preferably, the process stream temperature in the adsorption tower can be from about −5° C. to about 50° C. More preferably, the process stream temperature in the adsorption tower can be from about 15° C. to about 40° C.

[0051] When passing through the adsorption column in the vapor phase, the process stream may be at a pressure as low as about 1 psig, about 5 psig, about 10 psig, about 20 psig, about 25 psig, or about 30 psig, or as high as about 40 psig, about 50 psig, about 60 psig, about 70 psig, about 80 psig, about 90 psig, or about 100 psig, or, for example, from about 1 psig to about 100 psig, from about 5 psig to about 90 psig, from about 10 psig to about The pressure can be any pressure within any range defined between any two of the aforementioned values, such as 80 psig, about 15 psig to about 70 psig, about 20 psig to about 60 psig, about 25 psig to about 50 psig, about 30 psig to about 40 psig, or about 20 psig to about 50 psig. Preferably, the process stream pressure in the adsorption tower can be from about 10 psig to about 90 psig. More preferably, the process stream pressure in the adsorption tower can be from about 15 psig to about 80 psig.

[0052] Water may be removed from the process stream by a drying step. The drying step may include contacting the process stream with a desiccant. The desiccant may include at least one adsorbent selected from the group consisting of anhydrous calcium chloride, anhydrous calcium sulfate, concentrated sulfuric acid, silica, activated carbon, and zeolite. The desiccant may be selected from the group consisting of anhydrous calcium chloride, anhydrous calcium sulfate, concentrated sulfuric acid, silica, activated carbon, zeolite, and combinations thereof. The desiccant may preferably be a 3A molecular sieve. It has been found that the 3A molecular sieve does not initiate or favor the decomposition of CF3I.

[0053] The drying step is preferably carried out immediately after the acid impurities have been removed from the process stream, as this removes water trapped in the scrubber, as well as any moisture present in the crude CF3I process stream, when the acid impurities are removed from the process stream by passing the process stream through a scrubber containing an aqueous basic solution.

[0054] Also, when acid impurities are removed from the process stream by passing the process stream through an adsorption tower containing an acid activator, it is preferred to conduct a drying step immediately after the acid impurities have been removed from the process stream, as this will remove any moisture that is present in the crude CF3I process stream as well as any moisture that is produced when the acid impurities are removed from the process stream.

[0055] Organic impurities can be removed from the process stream by a separation step. The separation step can include distilling the process stream. Distilling the process stream can include a first distillation and a second distillation. The first distillation can remove organic impurities having a boiling point lower than that of CF3I from the process stream. Such low-boiling organic impurities can include, for example, CO2. The second distillation can remove organic impurities having a boiling point higher than that of CF3I from the process stream. Such high-boiling organic impurities can include, for example, CH3I. Because the boiling point of CH3I at standard conditions is 42°C, which is much higher than the boiling point of CF3I, which is −22°C at standard conditions, separation of CH3I from the process stream containing CF3I by distillation can be preferred.

[0056] Alternatively, or in addition, the distillation process may include a single distillation in which organic impurities having a boiling point lower than that of CF3I are passed to an overhead stream to remove the same, followed by a distillation in which the CF3I is passed to an overhead stream, but the organic impurities in the reboiler have a higher boiling point than the CF3I concentrate.

[0057] The distillation of the process stream can be carried out either as a continuous or batch process, with a single distillation being more suitable for a batch process, while a distillation process comprising a first distillation and a second distillation may be more suitable for a continuous process.

[0058] a purified process stream after reacting with an aqueous base and / or contacting with an acid activator to remove at least a portion of the acid impurities, drying the process stream to remove at least a portion of the water, and separating at least a portion of the organic impurities from the process stream. The concentration of CF3I in the purified process stream may be greater than about 99% by weight. Preferably, the concentration of CF3I in the purified process stream may be greater than about 99.5% by weight. More preferably, the concentration of CF3I in the purified process stream may be greater than about 99.9% by weight. Most preferably, the concentration of CF3I in the purified process stream may be greater than about 99.99% by weight.

[0059] After reacting with an aqueous base solution and / or contacting with an acid activator to remove at least a portion of the acid impurities, drying the process stream to remove at least a portion of the water, and separating at least a portion of the organic impurities from the process stream, the concentration of CH3I in the purified process stream may be less than about 50 parts per million (ppm). Preferably, the concentration of CH3I in the purified process stream may be less than about 20 ppm. More preferably, the concentration of CH3I in the purified process stream may be less than about 10 ppm. Most preferably, the concentration of CH3I in the purified process stream may be less than about 5 ppm.

[0060] After reacting with an aqueous base solution and / or contacting with an acid activator to remove at least a portion of the acid impurities, drying the process stream to remove at least a portion of the water, and separating at least a portion of the organic impurities from the process stream, the concentration of acid impurities in the purified process stream may be less than about 20 parts per million (ppm). Preferably, the concentration of acid impurities in the process stream may be less than about 10 ppm. More preferably, the concentration of acid impurities in the purified process stream may be less than about 5 ppm. Most preferably, the concentration of acid impurities in the purified process stream may be less than about 1 ppm.

[0061] After reacting with the aqueous base solution and / or contacting with the acid activator to remove at least some of the acid impurities, drying the process stream to remove at least some of the water, and separating at least some of the organic impurities from the process stream, the concentration of water in the purified process stream may be less than about 100 parts per million (ppm). Preferably, the concentration of water in the process stream may be less than about 50 ppm. More preferably, the concentration of water in the purified process stream may be less than about 30 ppm. Most preferably, the concentration of water in the purified process stream may be less than about 10 ppm.

[0062] It has been found that the purified process stream produced as described above can result in a high purity CF3I product. The process produces good process yields and is suitable for the production of CF3I on a commercial scale.

[0063] Figure 1 is a process flow diagram illustrating a process 10 for producing high purity CF3I. As shown in Figure 1, process 10 may include a crude process stream 12 and an aqueous basic solution 14 entering a scrubber 16. The crude process stream 12 and the aqueous basic solution 14 may be as described above. The aqueous basic solution 14 may react with the crude process stream 12 in the scrubber 16 to neutralize and dissolve acid impurities found in the crude process stream 12 to form a first intermediate process stream 18. The reacted aqueous basic solution 14, including the neutralized and dissolved acid impurities, may exit the scrubber through a scrubber waste stream 20 for disposal or reuse.

[0064] The first intermediate process stream 18 may flow to an adsorption tower 22. The adsorption tower 22 may contain any of the desiccants described above. When the first intermediate process stream 18 contacts the desiccant in the adsorption tower 22, the desiccant adsorbs the water in the first intermediate process stream 18 to produce a dried second intermediate process stream 24.

[0065] The second intermediate process stream 24 may flow to a first distillation column 26. The first distillation column 26 may be configured to separate organic impurities having a boiling point lower than CF3I from the second intermediate process stream 24. The separated organic impurities having a boiling point lower than CF3I may be removed through a volatile organic overhead stream 30. The CF3I and remaining organic impurities may exit the bottom of the first distillation column 26 to form a third intermediate process stream 32.

[0066] The third intermediate process stream 32 may flow to a second distillation column 34. The second distillation column 34 may be configured to separate organic impurities having a boiling point higher than CF3I from the third intermediate process stream 32. High-purity CF3I is collected from the above-mentioned product overhead process stream 36. Organic impurities having a boiling point higher than CF3I, such as CH3I, may exit the bottom of the second distillation column 34 to form a non-volatile organic waste stream 38.

[0067] Figure 2 is a process flow diagram illustrating another process 40 for producing high purity CF3I. As shown in Figure 2, process 40 may include a crude process stream 42 entering a first distillation column 44. Crude process stream 42 may be as described above. First distillation column 44 may be configured to separate organic impurities having a boiling point lower than CF3I from crude process stream 42. The separated organic impurities having a boiling point lower than CF3I may be removed through a volatile organic overhead stream 46. CF3I and remaining organic impurities may exit the bottom of first distillation column 44 to form a first intermediate process stream 48.

[0068] The first intermediate process stream 48 may flow to a second distillation column 50. The second distillation column 50 may be configured to separate organic impurities having a boiling point higher than CF3I from the first intermediate process stream 48 to form a second intermediate process stream 52 from the overhead of the second distillation column 50. The organic impurities having a boiling point higher than CF3I, such as CH3I, may exit the bottom of the second distillation column 50 to form a non-volatile organic waste stream 54.

[0069] The second intermediate process stream 52 and the basic aqueous solution 56 may enter a scrubber 58. The basic aqueous solution may be as described above. The basic aqueous solution 56 may react with the second intermediate process stream 52 in the scrubber 58 to neutralize and dissolve acid impurities found in the second intermediate process stream 52 to form a third intermediate process stream 60. The reacted basic aqueous solution 56, including the neutralized and dissolved acid impurities, may exit the scrubber through a scrubber waste stream 62 for disposal or reuse.

[0070] The third intermediate process stream 60 may flow to an adsorption tower 64. The adsorption tower 64 may contain any of the desiccants described above. When the third intermediate process stream 60 contacts the desiccant in the adsorption tower 64, the desiccant adsorbs water in the third intermediate process stream 60 to produce the dried high-purity CF3I process stream 66 described above.

[0071] FIG. 3 is a process flow diagram illustrating another process 68 for producing high-purity CF3I. As shown in FIG. 3, process 68 may include a crude process stream 70, an adsorption tower 72. The crude process stream 70 may be as described above. The adsorption tower 72 may include a first acid activator 74, a second acid activator 76, and a drying agent 78. The first acid activator 74 may be any of the acid activators described above, such as, for example, alumina P-188. The second acid activator 76 may be any of the acid activators described above, so long as it is different from the first acid activator 74. The second acid activator 76 may be, for example, alumina CLR-204. Two or more acid activators may be used because different acid activators may have higher affinities for different acid impurities. The use of the above acid activators may be preferred. The desiccant 78 may be any of the desiccants described above, such as, for example, 3A molecular sieves.

[0072] The crude process stream 70 may enter an adsorption tower 72 and contact a first acid activator 74 and then a second acid activator 76 to remove at least a portion of the acid impurities from the crude process stream 70. The crude process stream 70 may then contact a drying agent 78 to remove at least a portion of the water from the crude process stream 70 to produce a first intermediate process stream 80.

[0073] First intermediate process stream 80 may flow to first distillation column 82. First distillation column 82 may be configured to separate organic impurities having a boiling point lower than CF3I from first intermediate process stream 80. The separated organic impurities having a boiling point lower than CF3I may be removed through volatile organic overhead stream 84. CF3I and remaining organic impurities may exit the bottom of first distillation column 82 to form second intermediate process stream 86.

[0074] The second intermediate process stream 86 may flow to a second distillation column 88. The second distillation column 88 may be configured to separate organic impurities having a boiling point higher than CF3I from the second intermediate process stream 86. High purity CF3I is collected from the product overhead process stream 90 described above. Organic impurities having a boiling point higher than CF3I, such as CH3I, may exit the bottom of the second distillation column 88 to form a non-volatile organic waste stream 92.

[0075] Figure 4 is a process flow diagram illustrating another process 94 for producing high purity CF3I. As shown in Figure 4, process 94 may include a crude process stream 96 entering a first distillation column 98. The crude process stream 96 may be as described above. The first distillation column 98 may be configured to separate organic impurities having a boiling point lower than that of CF3I from the crude process stream 96. The separated organic impurities having a boiling point lower than that of CF3I may be removed through a volatile organic overhead stream 100. The CF3I and remaining organic impurities may exit the bottom of the first distillation column 98 to form a first intermediate process stream 102.

[0076] The first intermediate process stream 102 may flow to a second distillation column 104. The second distillation column 104 may be configured to separate organic impurities having a boiling point higher than CF3I from the first intermediate process stream 102 to form a second intermediate process stream 106 from the overhead of the second distillation column 104. The organic impurities having a boiling point higher than CF3I, such as CH3I, may exit the bottom of the second distillation column 104 to form a non-volatile organic waste stream 108.

[0077] The second intermediate process stream 106 may flow into an adsorption tower 110. The adsorption tower 110 may include a first acid activator 112, a second acid activator 114, and a desiccant 116. The first acid activator 112 may be any of the acid activators described above, such as, for example, alumina P-188. The second acid activator 114 may be any of the acid activators described above, so long as it is different from the first acid activator 112. The second acid activator 114 may be, for example, alumina CLR-204. The desiccant 116 may be, for example, any of the desiccant agents described above, such as, for example, 3A molecular sieve.

[0078] At least a portion of the acid impurities are removed from the second intermediate process stream 106 as the second intermediate process stream 106 enters an adsorption tower 110 and contacts a first acid activator 112 and then a second acid activator 114. The second intermediate process stream 106 is then adsorbed to an adsorption tower 110. The ream 106 may contact a desiccant 116 to remove at least a portion of the water from the second intermediate process stream 106 to produce a dry, high purity CF3I process stream 118, as described above.

[0079] While this invention has been described with reference to exemplary designs, the present invention can be further modified within the spirit and scope of this disclosure. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains.

[0080] As used herein, the phrase "within any range defined between any two of the preceding values" means that any range may be selected from any two of the values ​​listed before such phrase, regardless of whether those values ​​are in the lower portion of the list or the upper portion of the list. For example, a pair of values ​​may be selected from two lower values, two higher values, or a lower value and an upper value. [Example]

[0081] Example 1: Effect of Alkali Metal Hydroxide Concentration on Crude CF3I This example demonstrates the effect of alkali metal hydroxide concentration on crude CF3I according to Equations 1 and 2 above. A 100 g quantity of crude starting material consisting of 99.88 GC area % CF3I, 0.08 GC area % CH3I, and 0.04 GC area % other organic impurities was charged into each of six 150 ml cylinders at room temperature. The six cylinders were evacuated before being charged with the crude starting material. Six different test solutions were prepared with varying concentrations of potassium hydroxide, ranging from 0 wt% to 20 wt%. A different one of the six test solutions was added to each of the six cylinders in a 50 ml volume. The average pressure of the sample cylinders was 70 psig at room temperature. The six cylinders were shaken at room temperature for five days. Five days is much longer than typical process contact times, but was chosen to provide a clear indication of the relative impact of various potassium hydroxide concentrations on the crude starting material.

[0082] After five days, aqueous and organic layer samples were withdrawn from each of the six cylinders. The six aqueous layer samples were analyzed by ion chromatography to determine the amount of fluoride produced during the interaction between crude CF3I and the six test solutions. The results are shown in Table 1 below. The six organic layer samples were analyzed by GC to determine the changes in the concentrations of CF3I, CH3I, and other organic impurities. The results are shown in Table 2.

[0083] Table 1 lists the fluoride concentration in ppm normalized to the amount of crude CF3I for each of the six concentrations of potassium hydroxide. The control sample represents the total free fluoride in the crude CF3I. Normalization for each sample was performed by dividing the fluoride concentration measured by ion chromatography by the total mass of CF3I in the crude sample measured by GC. [Table 1]

[0084] As shown in Table 1, at potassium hydroxide concentrations greater than about 0.5 wt.%, the fluoride concentration increased by more than 10 ppm over the control sample not exposed to potassium hydroxide. The increase in fluoride is believed to be entirely due to the decomposition of CF3I. Therefore, to maintain a high yield of CF3I throughout the purification process, a potassium hydroxide concentration of about 0.01 wt.% to about 0.5 wt.% may be preferred.

[0085] Table 2 lists the concentrations of CF3I, CH3I, and other organic impurities for each of six concentrations of potassium hydroxide. [Table 2]

[0086] As shown in Table 2, at potassium hydroxide concentrations greater than about 1 wt.%, a significant portion of the CH3I present in the crude CF3I is removed by the potassium hydroxide solution. Therefore, to remove significant amounts of CH3I, potassium hydroxide concentrations of about 1 wt.% to about 20 wt.% may be preferred. Considering Tables 1 and 2 together, to balance the need to maintain CF3I and remove CH3I, potassium hydroxide concentrations of about 0.5 wt.% to about 5 wt.% may be preferred. Example 2: Effect of Alkali Metal Carbonate Concentration on Crude CF3I

[0087] This example demonstrates the effect of alkali metal carbonate concentration on crude CF3I according to Equations 1 and 2 above. A 100 g quantity of crude starting material consisting of 99.88 GC area % CF3I, 0.08 GC area % CH3I, and 0.03 GC area % other organic impurities was charged into each of six 150 ml cylinders at room temperature. The six cylinders were evacuated before being charged with the crude starting material. Six different test solutions were prepared with varying concentrations of sodium carbonate, ranging from 0 wt% to 20 wt%. A different one of the six test solutions was added to each of the six cylinders in a 50 ml volume. The average pressure of the sample cylinders was 70 psig at room temperature. The six cylinders were shaken at room temperature for five days. Five days, while much longer than typical process contact times, was chosen to provide a clear indication of the relative impact of various concentrations of sodium carbonate on the crude starting material.

[0088] After five days, aqueous and organic layer samples were withdrawn from each of the six cylinders. The six aqueous layer samples were analyzed by ion chromatography to determine the amount of fluoride produced during the interaction between crude CF3I and the six test solutions. The results are shown in Table 3 below.

[0089] Table 3 lists the fluoride concentration in ppm normalized to the amount of crude CF3I for each of the six concentrations of sodium carbonate. [Table 3] Table 3

[0090] As shown in Table 3, at sodium carbonate concentrations above about 5 wt% to 10 wt%, the fluoride concentration increased by more than 10 ppm over the control sample not exposed to sodium carbonate. The increase in fluoride is believed to be entirely due to the decomposition of CF3I. Therefore, to maintain a high yield of CF3I throughout the purification process, a sodium carbonate concentration of about 0.5 wt% to about 5 wt% may be preferred.

[0091] Six organic layer samples were analyzed by GC to determine changes in the concentrations of CF3I, CH3I, and other organic impurities. No significant differences were observed among the six organic layer samples. Thus, sodium carbonate solution did not have a significant effect on CH3I concentration, even at concentrations up to 20 wt%. Without wishing to be bound by theory, it is believed that the difference in reactivity between potassium hydroxide and sodium carbonate toward removing CH3I may be due to the fact that hydroxide ions are better nucleophiles than carbonate ions and readily undergo substitution reactions with CH3I. This same effect may also explain why potassium hydroxide is observed to decompose CF3I at lower concentrations than sodium carbonate. Example 3: Removal of acid impurities and water from crude CF3I using alumina

[0092] This example demonstrates the effectiveness of alumina in removing acid impurities from crude CF3I. The adsorption column was constructed from a 24-inch long, three-quarter-inch diameter perfluoroalkoxyalkane polymer tube prepared by including a layer of P-188 alumina, a layer of CLR-204 alumina, and a layer of 3A molecular sieve. Each layer was approximately 8 inches long. An additional thin layer of anhydrous calcium sulfate was inserted into the 3A molecular sieve layer to demonstrate the use of the 3A molecular layer. The column was wrapped in foil to prevent interaction with light.

[0093] Approximately 30 lbs of liquid-phase crude CF3I was circulated through the column. The crude CF3I entered the column through two alumina layers and exited through a 3A molecular sieve layer. The crude CF3I was circulated through the column for 7 days. Although 7 days is much longer than typical process contact times, it was chosen to provide a clear indication of the relative impact of the two alumina layers on the crude starting material.

[0094] After 7 days, a sample of crude CF3I was analyzed for acid impurity and water concentration. Acid impurity concentration was determined by acid-base titration. Water concentration was determined by Karl Fischer titration. The results are shown in Table 4 below. [Table 4] Table 4

[0095] A sample of crude CF3I was also analyzed by GC to determine the changes in the concentrations of CF3I, CH3I, and other organic impurities. The results are shown in Table 5. [Table 5] Table 5

[0096] Considering Tables 4 and 5 together, the adsorption column containing alumina and desiccant significantly reduced acid impurities and water, but did not cause measurable decomposition of CF3I. Example 4: Distillation of crude CF3I

[0097] This example demonstrates the effectiveness of distillation in removing CH3I from crude CF3I. The reboiler of a distillation column was charged with 180 lbs of crude starting material consisting of 99.4 GC area % CF3I, 0.4 GC area % CH3I, and 0.2 GC area % other organic impurities. The column was operated at pressures ranging from 60 to 80 psig, temperatures ranging from 30 to 40°C, and a differential pressure of 10 to 30 inches of water. Desorption rates ranged from 0.5 to 3 lbs / hr.

[0098] Approximately 5-10 lbs of noncondensable gases and low-boiling impurities were removed in the overhead stream, followed by CF3I. The purity of the CF3I was greater than 99.99% with a CH3I level of less than 5 ppm. The distillation yield ranged from 90-97%. CH3I and other high-boiling impurities were condensed in the reboiler. After distillation, approximately 2-5 lbs of organic impurities were collected from the reboiler. Example 5: Purification process of crude CF3I

[0099] This example demonstrates the effectiveness of the purification process. A crude feedstock amounting to 11,323 lbs was bubbled through 1,382 lbs of a 0.52 wt. % KOH aqueous solution. The crude feedstock consisted of CFI (99.78 GC area %), CHI (0.15 GC area %), and others (0.07 GC area %), with a total acidity of 50 ppm and a water content of 15 ppm. The feedstock tank containing the crude feedstock was maintained at a temperature of 30°C while the crude feedstock was charged by differential pressure at a flow rate of approximately 5 lbs / min into a caustic tank containing a 0.5 wt. % KOH solution. The crude feedstock was bubbled as a gas through the 0.5 wt. % KOH solution. Assuming that the crude feedstock (gas) only contacts approximately 10% of the 0.5 wt. % KOH solution in the tank in any given case, a flow rate of approximately 5 lbs / min corresponds to a contact time of approximately 27.64 minutes. The resulting effluent gas stream from the caustic tank was passed through a drying column packed with 3 Å molecular sieves and then solidified in the reboiler of the distillation tower.

[0100] During distillation in the column, cooling water at about 2°C to 5°C was circulated through a condenser at the top of the column, while the reboiler temperature was maintained at about 10°C to 20°C. During distillation, noncondensable gases and low-boiling impurities, followed by 10,312 lbs of CF3I, were removed through a 283 lbs overhead stream at a rate of about 250 lbs / hr. The resulting CF3I was measured by GC and found to have a purity of greater than 99.99 wt%, a CH3I concentration of less than 5 ppm, a total acid concentration of less than 0.1 ppm, and a water concentration of less than 5 ppm. Approximately 390 lbs of high-boiling impurities were recovered from the reboiler. The material balance of the integrated purification process was about 97%. The yield was about 91%. Ion chromatography analysis of the 0.5 wt% KOH solution after contact with the crude feed revealed the presence of about 10 ppm fluoride ion, indicating that despite the long contact time, the amount of CF3I reacted with KOH during the acid removal step in the caustic tank containing the 0.5 wt% KOH solution was not significant. Aspects

[0101] Aspect 1 is a method for purifying trifluoroiodomethane, the method comprising: providing a process stream comprising trifluoroiodomethane, organic impurities, and acid impurities; reacting the process stream with an aqueous basic solution comprising water and at least one base selected from the group of alkali metal carbonates and alkali metal hydroxides; and separating at least a portion of the organic impurities from the process stream.

[0102] Aspect 2 is the method of aspect 1, wherein the basic aqueous solution consists essentially of water and at least one base selected from the group of alkali metal carbonates and alkali metal hydroxides.

[0103] Aspect 3 is the method of aspect 2, wherein the basic aqueous solution consists of water and at least one base selected from the group of alkali metal carbonates and alkali metal hydroxides.

[0104] A fourth aspect is the method of any one of the first to third aspects, wherein in the reacting step, the base comprises an alkali metal carbonate.

[0105] Aspect 5 is the method of aspect 4, wherein in the reacting step, the base consists essentially of an alkali metal carbonate.

[0106] Aspect 6 is the method of aspect 4, wherein in the reacting step, the base comprises an alkali metal carbonate.

[0107] A seventh embodiment is the method of any one of the fourth to sixth embodiments, wherein the concentration of the alkali metal carbonate in the basic aqueous solution is about 0.01% by weight to about 20% by weight.

[0108] An eighth embodiment is the method of any one of the fourth to sixth embodiments, wherein the concentration of the alkali metal carbonate in the basic aqueous solution is about 0.1% by weight to about 10% by weight.

[0109] A ninth embodiment is the method of any one of the fourth to sixth embodiments, wherein the concentration of the alkali metal carbonate in the basic aqueous solution is about 0.5% by weight to about 5% by weight.

[0110] A tenth embodiment is the method of any one of the fourth to sixth embodiments, wherein the concentration of the alkali metal carbonate in the basic aqueous solution is about 5% by weight.

[0111] Example 11 is the method of any one of Examples 4 to 10, wherein the alkali metal carbonate is selected from the group consisting of sodium carbonate, potassium carbonate, lithium carbonate, and combinations thereof.

[0112] Example 12 is the method of example 11, wherein the alkali metal carbonate comprises sodium carbonate.

[0113] Embodiment 13 is the method of any of embodiments 11 or 12, wherein the alkali metal carbonate comprises potassium carbonate. This is a method for

[0114] Example 14 is the method of any one of Examples 11 to 13, wherein the alkali metal carbonate comprises lithium carbonate.

[0115] Example 15 is the method of example 11, wherein the alkali metal carbonate consists essentially of sodium carbonate.

[0116] Example 16 is the method of example 11, wherein the alkali metal carbonate comprises sodium carbonate.

[0117] Example 17 is the method of example 11, wherein the alkali metal carbonate consists essentially of potassium carbonate.

[0118] Example 18 is the method of example 11, wherein the alkali metal carbonate comprises potassium carbonate.

[0119] Example 19 is the method of example 11, wherein the alkali metal carbonate consists essentially of lithium carbonate.

[0120] Example 20 is the method of example 11, wherein the alkali metal carbonate comprises lithium carbonate.

[0121] Aspect 21 is the method of any one of Aspects 1 to 3, wherein in the reacting step, the base comprises an alkali metal hydroxide.

[0122] Example 22 is the method of example 21, wherein in the reacting step, the base consists essentially of an alkali metal hydroxide.

[0123] Aspect 23 is the method of aspect 21, wherein in the reacting step, the base comprises an alkali metal hydroxide.

[0124] A twenty-fourth embodiment is the method of any one of the twenty-first to twenty-third embodiments, wherein the concentration of the alkali metal hydroxide in the basic aqueous solution is about 0.01% by weight to about 20% by weight.

[0125] Aspect 25 is the method of any one of Aspects 21 to 23, wherein the concentration of the alkali metal hydroxide in the basic aqueous solution is about 0.1% by weight to about 5% by weight.

[0126] Aspect 26 is the method of any one of Aspects 21 to 23, wherein the concentration of the alkali metal hydroxide in the basic aqueous solution is about 0.5% by weight to about 1% by weight.

[0127] Example 27 is the method of any one of Examples 21 to 23, wherein the concentration of the alkali metal hydroxide in the basic aqueous solution is about 0.5 wt %.

[0128] Example 28 is the method of any one of Examples 21 to 27, wherein the alkali metal hydroxide is selected from the group consisting of sodium hydroxide, potassium hydroxide, lithium hydroxide, and combinations thereof.

[0129] Example 29 is the method of example 28, wherein the alkali metal hydroxide comprises sodium hydroxide.

[0130] Example 30 is the method of any of Examples 28 or 29, wherein the alkali metal hydroxide comprises potassium hydroxide.

[0131] Example 31 is the method of any one of Examples 28 to 30, wherein the alkali metal hydroxide comprises lithium hydroxide.

[0132] Example 32 is the method of example 28, wherein the alkali metal hydroxide consists essentially of sodium hydroxide.

[0133] Example 33 is the method of example 28, wherein the alkali metal hydroxide comprises sodium hydroxide.

[0134] Example 34 is the method of example 28, wherein the alkali metal hydroxide consists essentially of potassium hydroxide.

[0135] Example 35 is the method of example 28, wherein the alkali metal hydroxide comprises potassium hydroxide.

[0136] Example 36 is the method of example 28, wherein the alkali metal hydroxide consists essentially of lithium hydroxide.

[0137] Example 37 is the method of example 28, wherein the alkali metal hydroxide comprises lithium hydroxide.

[0138] Example 38 is the method of any one of Examples 1 to 37, wherein the temperature of the process stream in the reacting step is from about 5°C to about 80°C.

[0139] Aspect 39 is the method of any one of Aspects 1 to 37, wherein the temperature of the process stream in the reacting step is from about 10°C to about 50°C.

[0140] Aspect 40 is the method of any one of Aspects 1 to 37, wherein in the reacting step, the temperature of the process stream is from about 20°C to about 40°C.

[0141] Example 41 is the method of any one of Examples 1 to 40, wherein in the reacting step, the process stream has a pressure of from about 1 psig to about 100 psig.

[0142] Example 42 is the method of any one of Examples 1 to 40, wherein in the reacting step, the process stream has a pressure of from about 3 psig to about 80 psig.

[0143] Example 43 is the method of any one of Examples 1 to 40, wherein in the reacting step, the pressure of the process stream is from about 5 psig to about 50 psig.

[0144] Example 44 is the method of any one of Examples 1 to 43, wherein the method is a continuous process.

[0145] Example 45 is the method of any one of Examples 1 to 43, wherein the method is a batch process.

[0146] Aspect 46 is directed to a method for preparing a methyl iodide-containing toluene-containing toluene solution, wherein in the providing step, the organic impurities include methyl iodide and the base is an alkali. Aspect 46. The method of any one of aspects 1-45, comprising a metal hydroxide, wherein the reacting step reduces the concentration of methyl iodide in the process stream by about 1% to about 70% by GC area % of total organic compounds.

[0147] Example 47 is the method of any of Examples 1-45, wherein in the providing step, the organic impurities comprise methyl iodide and the base comprises an alkali metal hydroxide, and the reacting step reduces the concentration of methyl iodide in the process stream by about 5% to about 50%, based on GC area % of total organic compounds.

[0148] Example 48 is the method of any of Examples 1-45, wherein in the providing step, the organic impurities comprise methyl iodide and the base comprises an alkali metal hydroxide, and the reacting step reduces the concentration of methyl iodide in the process stream by about 5% to about 30% by GC area % of total organic compounds.

[0149] Example 49 is the method of any one of Examples 1 to 46, wherein the reacting step precedes the separating step.

[0150] Embodiment 50 is the method of any of embodiments 1 to 46, wherein the reacting step is followed by a separating step.

[0151] Example 51 is the method of any of Examples 1-48, further comprising an additional drying step immediately after the reacting step to remove at least a portion of the water from the process stream.

[0152] Example 52 is the method of example 51, wherein the drying step comprises contacting the process stream with a desiccant.

[0153] Example 53 is the method of example 52, wherein the desiccant comprises at least one adsorbent selected from the group consisting of anhydrous calcium chloride, anhydrous calcium sulfate, concentrated sulfuric acid, silica, activated carbon, and zeolite.

[0154] Example 54 is the method of example 51, wherein the drying step comprises passing the process stream through at least one 3A molecular sieve.

[0155] Example 55 is a method of any one of Examples 1 to 54, wherein the process stream after the reacting, drying, and separating steps comprises at least about 99% by weight trifluoroiodomethane.

[0156] Example 56 is a method of any one of Examples 1 to 54, wherein the process stream after the reacting, drying, and separating steps comprises at least about 99.5 wt.% trifluoroiodomethane.

[0157] Example 57 is a method of any one of Examples 1 to 54, wherein the process stream after the reacting, drying, and separating steps comprises at least about 99.9 wt.% trifluoroiodomethane.

[0158] Example 58 is the method of any of Examples 1-52, wherein the process stream after the reacting, drying, and separating steps comprises at least about 99.99 wt.% trifluoroiodomethane.

[0159] Embodiment 59 is directed to a process wherein the process stream after the reacting, drying, and separating steps comprises about 5 59. The method of any one of aspects 1-58, comprising less than 0 ppm methyl iodide.

[0160] Example 60 is the method of any of Examples 1-58, wherein the process stream after the reacting, drying, and separating steps comprises less than about 20 ppm methyl iodide.

[0161] Example 61 is the method of any of Examples 1-58, wherein the process stream after the reacting, drying, and separating steps comprises less than about 10 ppm methyl iodide.

[0162] Example 62 is the method of any of Examples 1-58, wherein the process stream after the reacting, drying, and separating steps comprises less than about 5 ppm methyl iodide.

[0163] Example 63 is the method of any of Examples 1-62, wherein the process stream after the reacting, drying, and separating steps comprises less than about 20 ppm acid impurities.

[0164] Example 64 is the method of any of Examples 1-62, wherein the process stream after the reacting, drying, and separating steps comprises less than about 10 ppm acid impurities.

[0165] Example 65 is the method of any of Examples 1-62, wherein the process stream after the reacting, drying, and separating steps comprises less than about 5 ppm acid impurities.

[0166] Example 66 is the method of any of Examples 1-62, wherein the process stream after the reacting, drying, and separating steps comprises less than about 1 ppm acid impurities.

[0167] Example 67 is the method of any of Examples 1-66, wherein the process stream after the reacting, drying, and separating steps comprises less than about 100 ppm water.

[0168] Example 68 is the method of any of Examples 1-66, wherein the process stream after the reacting, drying, and separating steps comprises less than about 50 ppm water.

[0169] Example 69 is the method of any of Examples 1-66, wherein the process stream after the reacting, drying, and separating steps comprises less than about 30 ppm water.

[0170] Example 70 is the method of any of Examples 1-66, wherein the process stream after the reacting, drying, and separating steps comprises less than about 10 ppm water.

[0171] Example 71 is a method of any one of Examples 1 to 70, wherein the separating step comprises distilling the process stream.

[0172] Example 72 is the method of example 71, wherein distillation of the process stream includes a first distillation that removes organic impurities from the process stream having a boiling point lower than CF3I, and a second distillation that removes organic impurities from the process stream having a boiling point higher than CF3I.

[0173] Example 73 is the method of example 71, wherein distilling the process stream comprises removing organic impurities having a boiling point lower than that of CF3I through an overhead stream, and subsequently obtaining CF3I through the overhead stream, wherein the organic impurities in the reboiler have a boiling point higher than that of the CF3I concentrate.

[0174] Embodiment 74 is a method for purifying trifluoroiodomethane, comprising providing a process stream comprising trifluoroiodomethane, organic impurities, and acid impurities. contacting the process stream with an acid reactant; and separating at least a portion of the organic impurities from the process stream.

[0175] Example 75 is the method of example 74, wherein the acid reactant comprises at least one adsorbent selected from the group consisting of alumina, alkali metal oxides, alkaline earth metal oxides, metal hydroxides, aluminosilicate minerals, zirconia, and silica.

[0176] Example 76 is the method of example 74, wherein the acid reactant comprises alumina.

[0177] Example 77 is the method of any one of Examples 74 to 76, wherein in the contacting step, the process stream is in a liquid phase and the temperature of the process stream is from about -50°C to about 50°C.

[0178] Example 78 is the method of any one of Examples 74 to 76, wherein in the contacting step, the process stream is in a liquid phase and the temperature of the process stream is from about 0°C to about 35°C.

[0179] Example 79 is the method of any one of Examples 74 to 76, wherein in the contacting step, the process stream is in a liquid phase and the temperature of the process stream is from about 10°C to about 30°C.

[0180] Example 80 is the method of any of Examples 74-79, wherein in the contacting step, the process stream is in the liquid phase and the pressure of the process stream is from about 1 psig to about 100 psig.

[0181] Example 81 is the method of any of Examples 74 to 79, wherein in the contacting step, the process stream is in the liquid phase and the pressure of the process stream is from about 10 psig to about 90 psig.

[0182] Example 82 is the method of any of Examples 74-79, wherein in the contacting step, the process stream is in the liquid phase and the pressure of the process stream is from about 20 psig to about 50 psig.

[0183] Example 83 is the method of any one of Examples 74 to 76, wherein in the contacting step, the process stream is in the gas phase and the temperature of the process stream is from about -20°C to about 60°C.

[0184] Example 84 is the method of any one of Examples 74 to 76, wherein in the contacting step, the process stream is in the gas phase and the temperature of the process stream is from about -5°C to about 50°C.

[0185] Example 85 is the method of any one of Examples 74 to 76, wherein in the contacting step, the process stream is in the gas phase and the temperature of the process stream is from about 15°C to about 40°C.

[0186] Example 86 is the method of any one of Examples 74 to 76 and 83 to 85, wherein in the contacting step, the process stream is in the vapor phase and the pressure of the process stream is from about 1 psig to about 100 psig.

[0187] Embodiment 87 is a process for contacting a process stream in a gas phase. The method of any one of Aspects 74 to 76 and 83 to 85, wherein the ream pressure is from about 10 psig to about 90 psig.

[0188] Example 88 is the process of any one of Examples 74-76 and 83-85, wherein in the contacting step, the process stream is in the vapor phase and the pressure of the process stream is from about 15 psig to about 80 psig.

[0189] Example 89 is the method of any one of Examples 74 to 88, wherein the method is a continuous process.

[0190] Example 90 is the method of any of Examples 74-88, wherein the method is a batch process.

[0191] Example 91 is the method of any one of Examples 74 to 90, wherein the contacting step precedes the separating step.

[0192] Example 92 is the method of any of Examples 74 to 90, wherein the contacting step is followed by the separating step.

[0193] Example 93 is the method of any of Examples 74-92, further comprising an additional drying step immediately after the contacting step to remove at least a portion of the water from the process stream.

[0194] Example 94 is the method of example 93, wherein the drying step comprises contacting the process stream with a desiccant.

[0195] Example 95 is the method of example 94, wherein the desiccant comprises at least one adsorbent selected from the group consisting of anhydrous calcium chloride, anhydrous calcium sulfate, concentrated sulfuric acid, silica, activated carbon, and zeolite.

[0196] Example 96 is the method of example 93, wherein the drying step comprises passing the process stream through at least one 3A molecular sieve.

[0197] Example 97 is the method of any of Examples 74-96, wherein the process stream after the contacting, drying, and separating steps comprises at least about 99 wt. % trifluoroiodomethane, less than about 50 ppm methyl iodide, less than about 100 ppm water, and less than about 20 ppm acid impurities.

[0198] Example 98 is the method of any of Examples 74-97, wherein the process stream after the reacting, drying, and separating steps comprises at least about 99% by weight trifluoroiodomethane.

[0199] Example 99 is the method of any of Examples 74-97, wherein the process stream after the reacting, drying, and separating steps comprises at least about 99.5 wt.% trifluoroiodomethane.

[0200] Example 100 is a method of any of Examples 74-97, wherein the process stream after the reacting, drying, and separating steps comprises at least about 99.9 wt.% trifluoroiodomethane.

[0201] Example 101 is the method of any of Examples 74-97, wherein the process stream after the reacting, drying, and separating steps comprises at least about 99.99 wt.% trifluoroiodomethane.

[0202] Example 102 is the method of any of Examples 74-101, wherein the process stream after the reacting, drying, and separating steps comprises less than about 50 ppm methyl iodide.

[0203] Example 103 is the method of any of Examples 74-101, wherein the process stream after the reacting, drying, and separating steps comprises less than about 20 ppm methyl iodide.

[0204] Example 104 is the method of any of Examples 74-101, wherein the process stream after the reacting, drying, and separating steps comprises less than about 10 ppm methyl iodide.

[0205] Example 105 is a method of any of Examples 74-101, wherein the process stream after the reacting, drying, and separating steps comprises less than about 5 ppm methyl iodide.

[0206] Example 106 is the method of any of Examples 74-105, wherein the process stream after the reacting, drying, and separating steps comprises less than about 20 ppm acid impurities.

[0207] Example 107 is the method of any of Examples 74-105, wherein the process stream after the reacting, drying, and separating steps comprises less than about 10 ppm acid impurities.

[0208] Example 108 is the method of any of Examples 74-105, wherein the process stream after the reacting, drying, and separating steps comprises less than about 5 ppm acid impurities.

[0209] Example 109 is the method of any of Examples 74-105, wherein the process stream after the reacting, drying, and separating steps comprises less than about 1 ppm acid impurities.

[0210] Example 110 is the method of any of Examples 74-109, wherein the process stream after the reacting, drying, and separating steps comprises less than about 100 ppm water.

[0211] Example 111 is the method of any of Examples 74-109, wherein the process stream after the reacting, drying, and separating steps comprises less than about 50 ppm water.

[0212] Example 112 is the method of any of Examples 74-109, wherein the process stream after the reacting, drying, and separating steps comprises less than about 30 ppm water.

[0213] Example 113 is the method of any of Examples 74-109, wherein the process stream after the reacting, drying, and separating steps comprises less than about 10 ppm water.

[0214] Example 114 is a method of any of Examples 74 to 113, wherein the separating step comprises distilling the process stream.

[0215] Example 115 is the method of Example 114, wherein distillation of the process stream includes a first distillation that removes organic impurities from the process stream having a boiling point lower than CF3I, and a second distillation that removes organic impurities from the process stream having a boiling point higher than CF3I.

[0216] Example 115 is the method of example 114, wherein distilling the process stream comprises removing organic impurities having a boiling point lower than that of CF3I through an overhead stream, followed by removing CF3I through an overhead stream, wherein the organic impurities in the reboiler have a boiling point higher than that of the CF3I concentrate.

Claims

1. 1. A method for purifying trifluoroiodomethane, comprising: providing a process stream comprising trifluoroiodomethane, organic impurities, and acid impurities; reacting the process stream with an aqueous basic solution, the aqueous basic solution comprising water and at least one base selected from the group of alkali metal carbonates and alkali metal hydroxides; and separating at least a portion of said organic impurities from said process stream.

2. 10. The method of claim 1, wherein in the reacting step, the at least one base comprises an alkali metal carbonate.

3. 3. The method of claim 2, wherein the concentration of the alkali metal carbonate in the basic aqueous solution is from about 0.01% to about 20% by weight.

4. The method of claim 2 wherein the alkali metal carbonate comprises sodium carbonate.

5. 10. The method of claim 1, wherein in the reacting step, the at least one base comprises an alkali metal hydroxide.

6. 6. The method of claim 5, wherein the concentration of the alkali metal hydroxide in the basic aqueous solution is from about 0.01% to about 20% by weight.

7. 7. The method of any one of claims 1 to 6, further comprising an additional drying step immediately following said reacting step to remove at least a portion of said water from said process stream, wherein said process stream after said reacting step, said drying step, and said separating step comprises at least about 99 wt% trifluoroiodomethane, less than about 50 ppm methyl iodide, less than about 100 ppm water, and less than about 20 ppm acid impurities.

8. 1. A method for purifying trifluoroiodomethane, comprising: providing a process stream comprising trifluoroiodomethane, organic impurities, and acid impurities; contacting the process stream with an acid reactant; and separating at least a portion of said organic impurities from said process stream.

9. The method of claim 8 , wherein the acid reactant comprises an alumina adsorbent.

10. 10. The method of claim 8, further comprising an additional drying step to remove at least a portion of the water from the process stream immediately after the contacting step, wherein the process stream after the contacting, drying, and separating steps comprises at least about 99 wt.% trifluoroiodomethane, less than about 50 ppm methyl iodide, less than about 100 ppm water, and less than about 20 ppm acid impurities.

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