Process for purifying a hydrogen halide solution containing organic impurities

Abstract

This disclosure relates to a novel plant method for purifying hydrogen halide solutions. The method includes halogenating an organic compound, particularly a phenolic compound, in the hydrogen halide solution to precipitate the halogenated compound. The halogenated compound can be filtered, the hydrogen halide solution is further purified on an adsorbent bed, and the cleaned hydrogen halide solution can be recycled or used in other processes.

Description

Technical Field

[0001] Various embodiments of this disclosure generally relate to methods for removing organic impurities, particularly phenolic impurities, from hydrogen halide solutions. It is particularly suitable for halogenated byproduct streams. Background Technology

[0002] In industrial processes, the halogenation (or oxidative halogenation) of organic compounds yields a wide range of commercial products. For example, brominated flame retardants such as tetrabromobisphenol A (TBBPA) are prepared by the bromination of an organic matrix, such as bisphenol, to produce TBBPA. The products of this bromination include valuable flame retardants, but also include aqueous byproduct streams that typically contain HBr and impurities. Chlorination also faces the challenge of dealing with aqueous byproduct streams.

[0003] For industrial processes to be commercially competitive, byproduct streams must be utilized or disposed of economically. This can include recycling the stream back into the process, transferring it to another process, or converting it into a separate commercial product. Disposal may be necessary when these options are unavailable, but simply disposing of industrial streams is both environmentally challenging and commercially inefficient, as it wastes the atomic value derived from the process. Therefore, recycling the stream back into the process, transferring it to another process, or converting it into a separate commercial product is highly preferred, but the impurity distribution of the byproduct stream becomes a significant obstacle that needs to be overcome. Summary of the Invention

[0004] Various embodiments of this disclosure generally relate to methods for treating hydrogen halide feed streams containing phenolic residues.

[0005] One embodiment of this disclosure may be a method of treating an HX stream by oxidative halogenation or by treating the stream with halogens to halogenate phenolic residues, thereby producing halogenated phenolic residues and a halogenated solution. The halogenated solution may be cooled and filtered to remove the halogenated phenolic residues from the halogenated solution, thereby producing a partially purified HX stream. The method may include the further step of passing the partially purified HX stream through an adsorbent bed to produce a purified HX stream.

[0006] In some embodiments, the HX stream comprises an HCl stream, an HBr stream, a HI stream, or a combination thereof. In some embodiments, the HX stream comprises an HCl or an HBr stream, or an HBr stream. The HX stream may be less than about 30% by weight, less than about 20% by weight, less than about 15% by weight, or less than about 12% by weight.

[0007] In some embodiments, the HX stream may contain less than about 5% by weight of phenolic residues, or less than about 3% by weight of phenolic residues, or less than about 1% by weight of phenolic residues.

[0008] In one embodiment, the HX stream, the partially purified HX stream, and the purified HX stream each contain HBr.

[0009] In some implementations, oxidative halogenation is oxidative bromination, and the halogen is bromine.

[0010] In some embodiments, oxidative halogenation is carried out at about 60°C or above, 80°C or above, or 90°C or above.

[0011] In some embodiments, the reactants after oxidative halogenation are cooled to about 60°C or lower; or the reactants are cooled to about 40°C or lower. In some embodiments, the reactants are cooled to at least about 20°C below the oxidative halogenation temperature.

[0012] In some embodiments, the ratio of halogen to phenolic residue is about 2:1 to 20:1 by weight; or the ratio of halogen to phenolic residue is about 8:1 to 12:1 by weight. Detailed Implementation

[0013] While the preferred embodiments of this disclosure have been explained in detail, it should be understood that other embodiments are contemplated. Therefore, the scope of this disclosure is not intended to be limited to the details of the construction and arrangement of the components set forth in the following description or illustrated in the accompanying drawings. This disclosure is capable of other embodiments and can be practiced or implemented in various ways. Furthermore, specific terminology will be used for clarity in describing the preferred embodiments.

[0014] It should also be noted that, as used in the specification and appended claims, the singular forms “a,” “an,” and “the” include plural indicators unless the context clearly indicates otherwise.

[0015] Furthermore, in describing preferred embodiments, terminology will be used for clarity. Each term is intended to encompass its broadest meaning as understood by those skilled in the art, and includes all technical equivalents that operate in a similar manner to achieve similar purposes.

[0016] A range may be expressed herein as from “about” or “approximately” a particular value and / or to “about” or “approximately” another particular value. When expressing such a range, another embodiment includes from one particular value and / or to another particular value.

[0017] "Comprising" or "including" means that at least the named compound, element, particle, or method step is present in the composition, article, or method, but does not exclude the presence of other compounds, materials, particles, or method steps, even if such other compounds, materials, particles, or method steps have the same function as the named compound.

[0018] It should also be understood that references to one or more method steps do not preclude the presence of additional method steps or intervening method steps between those explicitly identified steps. Similarly, it should be understood that references to one or more components in an apparatus or system do not preclude the presence of additional components or intervening components between those explicitly identified components.

[0019] This disclosure was developed as part of a plant process development procedure. The bromination of organic compounds (i.e., electrophilic substitution of bromine on an aromatic ring) produces hydrobromic acid, also known as hydrogen bromide, which must be utilized or disposed of. However, HBr streams present numerous challenges. In particular, phenolic compounds from some processes can complicate the utilization and / or treatment of byproduct streams. Attempts to recover bromine value from HBr are difficult due to the presence of organic impurities. A common option in any plant process is to recycle the stream back to the process or related processes, or to convert the stream into another product. However, recycling untreated HBr streams can lead to the generation of undesirable byproducts, which can cause several complications, including, but not limited to, reduced purity of the final product or solid precipitation in the equipment and / or equipment blockage.

[0020] As part of the process development for this plant, a method for removing most organic impurities, particularly phenolic impurities dissolved in HBr, has been developed. It has been found that organic impurities in the TBBPA byproduct stream can be removed by reacting with bromine and / or chlorine, converting soluble impurities into precipitable halogenated compounds with much lower solubility. Solids are removed by filtration, yielding HBr with a significantly reduced brominated impurity content in solution. If desired, these brominated impurities can be further reduced by passing them through a carbon bed or resin bed. The reaction with bromine can be carried out with an excess of 2 to 20 times, preferably 10 times, of bromine to ensure complete bromination of all phenolic impurities. Higher bromination temperatures are preferred to reduce reaction time. Reaction temperatures above 60°C, and preferably above 90°C, are recommended. The HBr solution purified by this method can be recycled to restore bromine value or for other applications. Notably, other processes relying on halogen oxidation can be similarly purified using this method.

[0021] Therefore, this disclosure includes a method for purifying an HX stream containing phenolic residues. The method may include treating the HX stream by oxidative halogenation to halogenate the phenolic residues, resulting in halogenated phenolic residues and a halogenated solution. The halogenated solution may be cooled and filtered to remove the halogenated phenolic residues, thereby producing a partially purified HX stream.

[0022] HX streams can be described as streams or solutions containing hydrohalides (also known as hydrogen halides). The term hydrohalides includes hydrohalic acids such as hydrochloric acid, hydrobromic acid, and hydroiodic acid, i.e., HCl, HBr, and HI. The compounds can also be described as hydrogen chloride, hydrogen bromide, and hydrogen iodide. Hydrohalides can be abbreviated as HX, where X is a recognized halogen, i.e., Cl, Br, or I. Hydrohalide solutions may contain HCl or HBr solutions, or they may contain HBr solutions. In some embodiments, the HX stream, a partially purified HX stream, and a purified HX stream may each independently contain HBr. Hydrohalide solutions or HX solutions may contain aqueous solutions. Hydrohalide solutions or HX solutions may contain partially halogenated organic compounds, or may contain organic compounds produced by a previous halogenation reaction.

[0023] The partially purified HX stream can be further processed. This processing may include passing the partially purified HX stream through an adsorbent bed to produce a purified HX stream. The adsorbent bed can be any adsorbent material used in industrial applications for removing organic compounds from aqueous streams in an acidic medium. The adsorbent bed may include a carbon bed (e.g., an activated carbon bed) or a neutral resin bed, such as a polystyrene bed, a polyvinylbenzene bed, or other polyaromatic resins.

[0024] HX feed streams may typically contain less than about 5% by weight, less than about 1% by weight, or less than about 0.5% by weight of phenolic residues. Phenolic residues may contain aromatic or pseudo-aromatic structures (such as quinone moieties) that are readily electrophilically substituted by halogens. Phenolic residues may include monobromophenols, dibromophenols, tribromophenols, and other phenols and / or aromatic or pseudo-aromatic products. Phenolic residues may be byproducts of bisphenol A bromination (IUPAC name: 4,4′-(propane-2,2-diyl)diol).

[0025] The HX flow rate can be less than about 50 wt% HX, less than about 40 wt% HX, or less than about 30 wt% HX. This method can be used for HX flows that have been depleted or diluted due to previous chemical methods. Therefore, the HX flow rate is preferably less than about 20 wt% HX, less than about 15 wt% HX, or less than about 12 wt% HX.

[0026] Oxidative halogenation of the initial HX feed stream can be carried out at or above any temperature at which electrophilic substitution can occur. Oxidative halogenation can be carried out at 25°C or above, 60°C or above, 70°C or above, 80°C or above, or 90°C or above. Oxidative halogenation can be carried out at even higher temperatures, but is generally limited by the pressure of the reaction medium. Oxidative halogenation can be carried out in dedicated equipment up to 200°C, but higher temperatures are generally considered unsafe.

[0027] Oxidative halogenation of the initial HX stream can be carried out with any halogen capable of electrophilic substitution over phenolic residues. Oxidative halogenation, or halogen oxidation, generally refers to treating a solution with a halogen at a temperature that halogenates the organic material in the solution, thereby generating a halogenated carbon bond and hydrogen halide. Oxidative halogenation can be carried out with bromine (e.g., oxidative bromination) or with chlorine (e.g., oxidative chlorination). Oxidative halogenation can also be carried out with a combination of chlorine and bromine. Oxidative halogenation can be carried out with a halogen that can be added to the HX stream, or with a halogen that can be generated in situ, such as converting HBr to bromine by adding chlorine, or converting HBr to bromine by adding hydrogen peroxide. The halogen in the HX solution does not need to be the same as the halogen in the oxidative halogenation. In one embodiment, HX can be HBr, and the halogen source can be bromine. In another embodiment, HX can be HBr, and the halogen source can be chlorine, during which a portion of the chlorine reacts with HBr to generate bromine and HCl, and the oxidative halogenation can be a mixture of chlorination and bromination. Preferably, the oxidative halogenation is oxidative bromination.

[0028] The oxidative halogenation of the initial HX feed stream can be carried out at a ratio of halogen to phenolic residues that effectively halogenates the phenolic residues. The ratio of halogen to phenolic residues can be from about 2:1 to about 20:1 by weight / weight, preferably from about 8:1 to about 12:1 by weight / weight.

[0029] Following oxidative halogenation, the halogenated solution can be cooled and then filtered. The halogenated solution can be cooled to at least about 10°C, or at least about 20°C, or at least about 30°C below the halogenation temperature. The halogenated solution can be cooled to below 60°C, below about 50°C, or below about 40°C. Cooling can be accomplished by any technique used in the manufacturing process. In one embodiment, residual halogens can be removed by stripping, such as by removing residual bromine from the halogenated solution.

[0030] Partially purified HX streams and purified HX streams can be used in other process reactions. For example, partially purified HBr streams can be chlorinated to produce bromine, which can then be stripped from solution and used in other bromination reactions to restore a valuable bromine value. Similarly, purified HX streams can be treated with chlorine to produce bromine.

[0031] One embodiment of this disclosure may be a method for purifying an HX stream containing less than about 1% by weight of phenolic residues, wherein an HX stream containing about 15% by weight or less of HX is treated with bromine or chlorine as a halogen at a temperature above 60°C to halogenate the phenolic residues and produce a halogenated solution. The halogenated solution may be cooled to below 60°C and filtered to produce a partially purified HX stream. The partially purified HX stream may be further processed by passing it through an adsorbent bed.

[0032] One embodiment of this disclosure may be a method for purifying an HBr stream containing about 1% by weight or less of phenolic residues, wherein the HBr stream containing about 15% by weight or less of HBr is treated with bromine as a halogen at a temperature above 60°C to brominate the phenolic residues and produce a halogenated solution. The halogenated solution may be cooled to below 60°C and filtered to produce a partially purified HBr stream. The partially purified HBr stream may be further processed by passing it through an adsorbent bed.

[0033] One embodiment of this disclosure may be a method for purifying an HBr stream containing about 1% by weight or less of phenolic residues, wherein the HBr stream containing about 15% by weight or less of HBr is treated with chlorine as a halogen at a temperature of about 80°C or higher to halogenate the phenolic residues and produce a halogenated solution. The halogenated solution may be cooled to about 60°C or lower and filtered to produce a partially purified HX stream. The partially purified HX stream may be further processed by passing it through an adsorbent bed.

[0034] One embodiment of this disclosure may be a method for purifying an HBr stream containing about 1% by weight or less of phenolic residues, wherein the HBr stream containing about 15% by weight or less of HBr is treated with bromine as a halogen at a temperature of about 90°C or higher to halogenate the phenolic residues and produce a halogenated solution. The halogenated solution may be cooled to about 60°C or lower and filtered to produce a partially purified HBr stream. The partially purified HBr stream may be further processed by passing it through an adsorbent bed.

[0035] One embodiment of this disclosure may be a method for purifying an HBr stream containing about 1% by weight or less of phenolic residues, wherein the HBr stream containing about 15% by weight or less of HBr is treated with bromine as a halogen at a temperature of about 90°C or higher to halogenate the phenolic residues and produce a halogenated solution. The halogenated solution may be cooled to about 40°C or lower and filtered to produce a partially purified HBr stream. The partially purified HBr stream may be further processed by passing it through an adsorbent bed.

[0036] Example

[0037] Example 1

[0038] The 3-necked 20L reactor was equipped with a mechanical stirrer, condenser, and thermometer sheath. A process waste stream containing approximately 10% HBr solution with 306 ppm phenolic impurities was used. Phenolic impurities were measured using liquid chromatography (LC). The HBr solution (16 kg) was added to the reactor and stirred. It was heated to 95°C using a heating mantle. When the solution temperature exceeded 50°C, 160 g of bromine was added and heating continued. After heating the mixture at 95°C for 30 minutes, heating was stopped and the condenser was switched from reflux to distillation. A vacuum pump was connected via two ice traps containing dilute sodium sulfite solution. The mixture was gradually cooled to 60°C by stripping unreacted bromine and some water under vacuum. It was then cooled to ambient temperature at atmospheric pressure. The mixture was then filtered using a medium-sized sintered glass funnel to remove precipitated solids. LC analysis of the filtered HBr solution showed only 26 ppm phenolic impurities. Passing it through a styrene resin column, LC analysis detected 0 ppm phenolic impurities in the HBr solution.

[0039] Example 2

[0040] A 500 mL thick-walled glass reactor with ACE fittings is equipped with a thermometer sleeve, a pressure gauge, and a Teflon top with a stopcock valve connected to a receiving flask via a condenser. The receiving flask is connected to a vacuum line via another condenser and trap. 300 g of waste stream HBr containing approximately 500 ppm phenolic impurities is charged into the reactor. Rapid heating is performed using a heating mantle while magnetic stirring. When the mixture reaches 50 °C, 3 g of bromine is added and the reactor is sealed. Within approximately 15 minutes, the mixture reaches 120 °C and the reactor pressure shows approximately 25 psi. After stirring the mixture at this temperature for 25 minutes, the heating mantle is lowered, and the pressure is released by carefully opening the top stopcock valve. The distilled liquid is collected in a receiver. A vacuum is slowly applied to cool the mixture to 60 °C; typically, a vacuum of 120 mmHg to 130 mmHg is required to reach 60 °C. The mixture is filtered at 60 °C; the hot HBr solution contains only 63 ppm phenolic impurities.

[0041] Example 3

[0042] 800 g of HBr samples (3-1A and 3-2A) were each treated with 80 g of bromine (i.e., 10% by weight), heated to 55 °C and 80 °C respectively, and held for 30 minutes. The mixtures were then heat-filtered at the end of their holding time and samples were taken for GC analysis. The results are shown in Table 1.

[0043] Allow the resulting solution to stand for approximately 4 hours to cool to room temperature. Filter the solution again before proceeding. Then chlorinate 400 g portions of each mixture (3-1B and 3-2B) at 80°C to look for the formation of any additional solids.

[0044] In a similar manner, two solutions of HBr (3-3 and 3-4) were treated with 1% wt% bromine, heated to 55°C and 80°C and held for 30 minutes, hot filtered, and samples were taken for GC analysis, then cooled to room temperature and filtered again.

[0045] Table 1

[0046]

[0047] Example 4

[0048] The HBr sample was filtered to remove solids and then sampled for analysis (4-0).

[0049] For 4-1A, 3083 g of HBr sample was placed in a 5 L flask and heated to 80 °C. Approximately 1 wt% (30 g) of bromine was carefully added below the liquid surface. The solution was mixed with a large stir bar for approximately 3 hours. The mixture was then filtered while hot, and the separated solids were washed with DI water. The hot solution was then divided into three equal portions. One portion (4-1B) was retained as is and allowed to stand overnight. The second portion (4-1C) was treated with just enough solid sodium sulfite to react and remove bromine, sampled for analysis, and allowed to stand overnight. The third portion (4-1D), 996 g, was placed in a 1 L flask and heated to 80 °C. 33 g of chlorine (sufficient to convert at least 75% of the HBr value) was added over approximately 5 minutes. The reaction mixture was stirred for 30 minutes and then filtered hot.

[0050] For sample 4-2, 950 g of HBr sample was placed in a 1 L flask and heated to 80 °C, followed by the addition of 5 g of bromine. The mixture was stirred for 3 hours, hot filtered, and then sampled for analysis.

[0051] The treatment of sample 4-3 was exactly the same as that of sample 4-2, except that it was heated to 95°C.

[0052] Table 2

[0053]

[0054]

[0055] Example 5

[0056] The HBr sample was filtered to remove solids and then sampled for analysis (sample 5-0).

[0057] In sample 5-1, 863.9 g of HBr sample was placed in a 1 L four-necked round-bottom flask. The mixture was heated to approximately 30 °C, and approximately 26 g of Cl2 was added over approximately 15 minutes. During the addition, the reaction temperature was raised to approximately 40 °C. The mixture was sampled at a holding time of 15 minutes (the sample was filtered before analysis). The experiment was stopped at a holding time of 30 minutes, and the remaining mixture was filtered. After treatment with just enough solid sodium sulfite to kill any residual bromine in the solution, a portion of the sample was submitted for complete analysis.

[0058] After standing at room temperature for about 6 hours, a solid was observed and the solution was filtered. After a total of about 16 hours of standing, additional solids were observed to form, and the solution was filtered again.

[0059] In sample 5-2, 866 g of HBr sample was loaded into the apparatus. The mixture was heated to approximately 60 °C, and approximately 26 g of Cl2 was added over approximately 15 minutes. The experiment was stopped after a holding time of 30 minutes, and the mixture was filtered while hot. The solution was allowed to stand at room temperature overnight and filtered again. A sample of the final solution was taken for analysis.

[0060] In sample 5-3, 878 g of HBr sample was loaded into the apparatus. The mixture was heated to approximately 80°C, and approximately 26 g of Cl2 was added over approximately 15 minutes. The experiment was stopped after a holding time of 30 minutes, and the mixture was filtered while hot. The solution was allowed to stand overnight at room temperature and filtered again. A sample of the final solution was taken for analysis.

[0061] In samples 5-4, 878 g of HBr sample was loaded into the apparatus. The mixture was heated to approximately 100 °C, and approximately 26 g of Cl2 was added over approximately 15 minutes. During the addition, the reaction temperature dropped to approximately 96 °C. The experiment was stopped after a holding time of 30 minutes, and the mixture was filtered while hot. The solution was allowed to stand at room temperature overnight and filtered again. A sample of the final solution was also taken for analysis. No solid was separated during hot filtration. Solid crystals were observed when the solution cooled.

[0062] In sample 5-5, 874 g of HBr sample was loaded into the apparatus. The mixture was heated to approximately 80°C. Excess bromine was added below the liquid surface until the solution was saturated. The experiment was stopped after a 30-minute holding time, and the mixture was filtered while hot. The solution was allowed to stand overnight at room temperature, but no further filtration was performed after overnight standing because only a very small amount of solid was formed. It appears that the solid produced by the bromine-only method is less soluble than the solid produced by the chlorination route.

[0063]

[0064] Example 6

[0065] Approximately 8% HBr solution was filtered and analyzed as Sample 6-0. 0.53 g, 0.843 g, and 1.652 g of granular activated carbon (Norit GAC 1240) were added to three 400 g aliquots of this 8% HBr solution, and the solutions were stirred at room temperature for 4 hours. All four samples were filtered through a 0.45 μm Whatman Autovial non-needle filter to remove fine carbon particles and analyzed. Data are reported in Table 4.

[0066] Table 4

[0067] Solution mass (grams) 400 400 400 400 GAC mass (grams) 0 0.53 0.843 1.652 time 0 240 240 240 Phenol (ppm) 12 7 5 1 Monobromophenol (ppm) 14 6 2 0 dibromophenol (ppm) 2 0 0 0 Tribromophenol (ppm) 24 19 12 0 TBBPA (ppm) 0 0 0 0 Unknown phenolic substances 360 165 44 5 Total phenolic compounds (ppm) 384 198 64 5

[0068] Example 7

[0069] 139.3 g of granular activated carbon (Norit GAC 1240) was packed into a 50 mm ID column, resulting in a bed volume of approximately 280 mL. An HBr solution containing phenolic compounds was pumped upwards through the bottom of the column at 5 mL / min. This resulted in a residence time of less than 1 hour. Samples were collected starting from the 1-hour feed time. The APHA color of multiple samples was analyzed, and a complete analysis was performed on a single sample (sample 7-1) collected at approximately 2.5 hours. APHA color data are provided in Table 5, and the analysis of the starting material and the sample extracted at 2.5 hours is presented in Table 6.

[0070] Table 5

[0071]

[0072]

[0073] Table 6

[0074] Br - weight % 9.47 9.46 Cl-weight% 0.26 0.32 Phenol (ppm) 0 0 Monobromophenol (ppm) 0 0 dibromophenol (ppm) 0 0 Tribromophenol (ppm) 14 0 TBBPA (ppm) 48 0 Unknown phenolic substances 162 7 Total phenolic compounds (ppm) 224 7 APHA as is 500 1

[0075] Example 7

[0076] An 11 mm diameter jacketed column was loaded with 15 g of styrene adsorption resin. A circulator with water was used to maintain a temperature of 60 °C. A pre-reacted, flash-cooled, and filtered HBr solution containing phenolic compounds was then pumped downwards through the adsorbent bed at a controlled rate via a peristaltic pump. The initial concentration of phenolic compounds in the HBr and the concentration of phenolic compounds in the total volume of HBr passing through the column were reported. The concentration of phenolic compounds was determined by HPLC analysis. Data are reported in Table 7.

[0077] Table 7

[0078]

[0079]

[0080] Implementation Plan

[0081] Alternatively or concurrently, this disclosure may include one or more of the following embodiments.

[0082] Implementation Scheme 1. A method for purifying an HX stream containing phenolic residues, comprising treating the HX stream by oxidative halogenation to halogenate the phenolic residues, thereby producing halogenated phenolic residues and a halogenated solution; cooling the halogenated solution; and filtering the halogenated phenolic residues from the halogenated solution to produce a partially purified HX stream.

[0083] Implementation Scheme 2. A method for purifying an HX stream containing phenolic residues, comprising treating the HX stream by oxidative halogenation to halogenate the phenolic residues, thereby producing halogenated phenolic residues and a halogenated solution; cooling the halogenated solution; filtering the halogenated phenolic residues from the halogenated solution to produce a partially purified HX stream; and passing the partially purified HX stream through an adsorbent bed to produce a purified HX stream. The adsorbent bed comprises a carbon bed or a polystyrene bed.

[0084] Implementation Scheme 3. A method for purifying an HBr stream containing about 1% by weight or less of phenolic residues, wherein the HBr stream containing about 15% by weight or less of HBr is treated with bromine as a halogen at above 60°C to bromine the phenolic residues and produce a halogenated solution. The halogenated solution can be cooled to below 60°C and filtered to produce a partially purified HBr stream. The partially purified HBr stream can be further processed by passing it through an adsorbent bed.

[0085] Implementation Scheme 4. The method according to one of the foregoing implementation schemes, wherein the oxidative halogenation is carried out at about 60°C or above, 80°C or above, or 90°C or above.

[0086] Implementation Scheme 5. The method according to one of the foregoing embodiments, wherein the reactants are cooled to at least about 20°C below the halogenation temperature. The reactants may be cooled to about 60°C or lower. The reactants may be cooled to about 40°C or lower.

[0087] Implementation Scheme 6. The method according to one of the foregoing embodiments, wherein the ratio of halogen to phenolic residue is about 2:1 to 20:1 by weight / weight. The stated ratio of halogen to phenolic residue may be about 8:1 to 12:1 by weight / weight.

[0088] Implementation Scheme 7. The method according to one of the foregoing implementation schemes, wherein the HX stream contains less than about 5% by weight, less than about 3% by weight, or less than about 1% by weight of phenolic residues.

[0089] Implementation Scheme 8. The method according to one of the foregoing implementation schemes, wherein the HX flow is less than about 30% by weight HX, less than about 20% by weight HX, less than about 15% by weight HX, or less than about 12% by weight HX.

[0090] Implementation Scheme 9. The method according to one of the foregoing implementation schemes, wherein the HX stream, the partially purified HX stream, and the purified HX stream each contain HBr.

[0091] Implementation Scheme 10. The method according to one of the foregoing implementation schemes, wherein the oxidative halogenation is oxidative bromination, and the halogen is bromine.

[0092] It should be understood that the embodiments and claims disclosed herein are not limited in their application to the details of the construction and arrangement of the components set forth in the specification and illustrated in the drawings. Rather, the specification and drawings provide examples of contemplated embodiments. The embodiments and claims disclosed herein are also capable of other embodiments and can be practiced and implemented in various ways. Furthermore, it should be understood that the wording and terminology used herein are for descriptive purposes and should not be construed as limiting the claims.

[0093] Therefore, those skilled in the art will understand that the concepts upon which this application and claims are based can readily be used as the basis for designing other structures, methods, and systems for implementing the embodiments set forth in this application and for the purposes of the claims. Therefore, it is important that the claims be considered to include such equivalent constructions.

Claims

1. A method for purifying an HX stream containing phenolic residues, comprising: The HX stream is treated by oxidative halogenation to halogenate the phenolic residues, thereby producing halogenated phenolic residues and a halogenated solution, wherein the oxidative halogenation is carried out with bromine and / or chlorine; Cool the halide solution; The halogenated phenolic residues are filtered from the halogenated solution to produce a partially purified HX stream; as well as The partially purified HX stream is passed through the adsorbent bed to generate a purified HX stream. The HX feed stream includes an HCl feed stream, an HBr feed stream, an HI feed stream, or a combination thereof.

2. The method of claim 1, wherein the HX stream contains less than 5% by weight of phenolic residues.

3. The method of any one of claims 1 to 2, wherein the HX stream contains less than 1% by weight of phenolic residues.

4. The method according to any one of claims 1 to 2, wherein the HX flow rate is less than 30% by weight of HX.

5. The method of any one of claims 1 to 2, wherein the HX flow rate is less than 15% by weight of HX.

6. The method of any one of claims 1 to 2, wherein the HX stream, the partially purified HX stream, and the purified HX stream each contain HBr.

7. The method according to any one of claims 1 to 2, wherein the oxidative halogenation is an oxidative bromination performed with bromine.

8. The method of any one of claims 1 to 2, wherein the oxidative halogenation is performed at 60°C or above.

9. The method according to any one of claims 1 to 2, wherein the oxidative halogenation is performed at 90°C or above.

10. The method of any one of claims 1 to 2, wherein the reaction is cooled to at least 20°C below the halogenation temperature.

11. The method of any one of claims 1 to 2, wherein the reaction is cooled to 60°C or lower.

12. The method of any one of claims 1 to 2, wherein the reaction is cooled to 40°C or lower.

13. The method of any one of claims 1 to 2, wherein the ratio of halogen to phenolic residue is 2:1 to 20:1 by weight / weight.

14. The method of any one of claims 1 to 2, wherein the ratio of halogen to phenolic residue is 8:1 to 12:1 by weight / weight.

15. The method of any one of claims 1 to 2, wherein the adsorbent bed comprises a carbon bed or a polystyrene bed.

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