Method for preparing chlorine from hydrogen chloride

Abstract

The present invention provides a method for preparing chlorine from hydrogen chloride, comprising the steps of: n+ and alkali cations and Cl - and circulating the liquid melt in a reactor system comprising three bubble lift reactors I, II and III, each comprising reaction zones i, ii and iii: (a) in reaction zone i of the first bubble lift reactor I, n+ and alkali cations and Cl - The liquid melt containing Cu and Cu in the molar ratio 2+ :Cu + Cu is contacted with oxygen at a temperature in the range of 395-405°C so that 2+ :Cu + (b) circulating the liquid melt obtained in (a) to reaction zone ii of a second bubble lift reactor II, where the liquid melt is contacted with hydrogen chloride at a temperature in the range of 395-405°C so that water is formed, thereby obtaining a liquid melt having increased Cl compared to the liquid melt obtained according to (a); - (c) circulating the liquid melt obtained in (b) to reaction zone iii of a third bubble lift reactor III operated at a temperature in the range of 420-430°C so as to form Cl2, and removing Cl2 in gaseous form from reaction zone iii and the third bubble lift reactor III, respectively, resulting in a liquid melt enriched in Cl2 compared to the liquid melt obtained according to (b); - The present invention further relates to a reactor system comprising three bubble lift reactors I, II and III. TIFF2022552572000003.tif87149

Description

[Technical Field]

[0001] The present invention relates to a method for preparing chlorine from hydrogen chloride, which comprises the steps of: n+ , alkali cations, and chloride ions Cl - and circulating the liquid melt in a reactor system comprising three bubble lift reactors I, II and III, each comprising reaction zones i, ii and iii: (a) in reaction zone i of the first bubble lift reactor I, copper ions Cu n+ , alkali cations, and chloride ions Cl - The liquid melt containing Cu and Cu in the molar ratio 2+ :Cu + The Cu content is increased by contacting the Cu alloy with oxygen (O2) at a temperature above 375°C. 2+ :Cu + (b) circulating the liquid melt obtained in (a) to reaction zone ii of a second bubble lift reactor II, where the liquid melt is contacted with hydrogen chloride (HCl) at a temperature above 355°C so as to form water, resulting in a liquid melt having increased chloride anions (Cl) compared to the liquid melt obtained according to (a); - (c) the liquid melt obtained in (b) is circulated to reaction zone iii of a third bubble lift reactor III operated at a temperature in the range of 400-480°C so that chlorine (Cl2) is formed, and Cl2 is removed in gaseous form from reaction zone iii and from the third bubble lift reactor III, respectively, resulting in a liquid melt enriched in Cl2 compared to the liquid melt obtained according to (b). - A liquid melt is left depleted of the

[0002] The present invention further relates to a reactor system comprising three bubble lift reactors I, II and III, each bubble lift reactor comprising reaction zones I, ii and iii; a liquid melt outlet in the upper region of each bubble lift reactor; and a liquid melt inlet in the lower region of each bubble lift reactor, the bubble lift reactors I, II and III being connected by connecting lines suitable for circulation of the liquid melt, so that a) the liquid melt outlet of the first bubble lift reactor I is connected by a connecting line to the liquid melt inlet of the second bubble lift reactor II; b) the liquid melt outlet of the second bubble lift reactor II is connected by a connecting line to the liquid melt inlet of the third bubble lift reactor III; and c) the liquid melt outlet of the third bubble lift reactor III is connected by a connecting line to the liquid melt inlet of the first bubble lift reactor I.

[0003] Furthermore, the present invention relates to a method for producing copper ions, such as chlorine, copper ions Cu, and copper ions Cu, wherein n is a number in the range of 1 to 2, which are obtained or can be obtained by the method of the present invention. n+ and potassium ions K + and chloride ions Cl - and a salt mixture containing Cu in a molar ratio ranging from 1:0.60 to 1:1.45. n+ :K + and copper ions Cu, where n is a number in the range of 1 to 2. n+ and potassium ions K + and chloride ions Cl - and Cu in a molar ratio ranging from 1:0.60 to 1:1.45. n+ :K + The present invention relates to a salt mixture for preparing chlorine from hydrogen chloride, which has the following structure: [Background technology]

[0004] Hydrogen chloride (HCl) is a waste product in several industrial processes, e.g., the preparation of isocyanates. HCl can be converted to chlorine (Cl2) by the so-called Deacon process. The Cl2 produced can then be used to manufacture other commercially valuable products, while simultaneously reducing the discharge of waste hydrochloric acid. The Deacon process is based on the gas-phase oxidation of hydrogen chloride: 4HCl + O2 → 2Cl2 + 2H2O. The reaction is carried out at approximately 400-450 °C in the presence of various catalysts, including, for example, copper chloride (CuCl2). The complete process involves three reactions: (1) oxidation of CuCl with oxygen to Cu2OCl2 (CuO.CuCl2): 2CuCl + 1 / 2O2 → Cu2OCl2 (oxidation); (2) reaction of Cu2OCl2 with gaseous HCl to CuCl2 and water: Cu2OCl2 + 2HCl → 2CuCl2 + H2O (chlorination); and (3) thermal decomposition of CuCl2 to CuCl and Cl2: 2CuCl2 → 2CuCl + Cl2 (dechlorination).

[0005] US 2,418,930 A discloses a two-stage Deacon process in molten salts, in which reaction (1) is carried out in a first stage and reactions (2) and (3) are combined in a second stage.

[0006] investigated the use of a molten salt mixture containing 45 mol% KCl and 55 mol% CuCl as a catalyst for the reaction of HCl with O to produce Cl in a single reactor consisting of a quartz tube. The conversion of HCl was measured at 400 and 450 °C (Su S., Mannini D., Metiu H., Gordon MJ, McFarland EW, Ind. Eng. Chem. Res. 2018, 57, 7795-7801).

[0007] An overview of the Deacon process is provided in Pavel Tokmakov's paper (Pavel Tokmakov: "Untersuchung zur Chemie des Deacon-Prozesses in Salzschmelzen," 2018). Tokmakov outlines the two-reactor concept and the three-reactor concept in Chapter 6, entitled "Suggestions for the technology" ("Vorschlage zur Technologie"), and concludes that the three-reactor concept is problematic, particularly from an energetic perspective. The temperatures disclosed for the three reactions, i.e., the three reactors, are 360-375 °C for oxidation (1), 355 °C for chlorination (2), and over 480 °C for dechlorination (3). The circulation of the liquid melt is identified as difficult, particularly in terms of the problem of keeping the melt liquid. Relatively large efforts have been proposed to overcome the problems with the three reactor concept, namely the use of airlift pumps and pressure differentials, and the temperatures proposed for the individual reactions result in large temperature differences between the reaction zones.

[0008] US 2,418,931A discloses a method for producing chlorine from hydrogen chloride, in which the temperature ranges of the first, second and third zones are 200 to 425°C in the first zone, 200 to 475°C in the second zone and 500 to 800°C in the third zone. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] US2,418,930A [Patent Document 2] US2,418,931A [Non-patent literature]

[0010] [Non-Patent Document 1] Su S., Mannini D., Metiu H. Gordon MJ, McFarland EW, Ind. Eng. Chem. Res. 2018, 57, pp. 7795-7801 [Non-patent document 2] Pavel Tokmakov: “Untersuchung zur Chemie des Deacon-Prozesses in Salzschmelzen”, 2018 Summary of the Invention [Problem to be solved by the invention]

[0011] The object of the present invention was to provide a new and advantageous process for preparing chlorine from hydrogen chloride which overcomes the above-mentioned problems, in particular a process which uses a three-reactor concept but which overcomes the problem of keeping the melt liquid and circulatable, while being simpler and more economical than the processes of the prior art. A further object of the present invention was to provide a reactor system for carrying out the process. A further object of the present invention was to provide an improved salt mixture containing copper ions for use in the process for preparing chlorine from hydrogen chloride, which salt mixture allows for a better space-time yield than the salt mixtures known from the prior art. [Means for solving the problem]

[0012] Therefore, the present invention provides a method for preparing chlorine from hydrogen chloride, comprising the step of: n+ , alkali cations, and chloride ions Cl - and circulating the liquid melt comprising the reaction zones i, ii, and iii in a reactor system comprising three bubble lift reactors I, II, and III, each comprising a reaction zone i, ii, and iii: (a) In the reaction zone i of the first bubble lift reactor I, copper ions Cu n+ , alkali cations, and chloride ions Cl - The liquid melt containing Cu and Cu in the molar ratio 2+ :Cu +The Cu content is increased by contacting the Cu alloy with oxygen (O2) at a temperature above 375°C. 2+ :Cu + A liquid melt with elevated temperature is obtained; (b) circulating the liquid melt obtained in (a) to reaction zone ii of a second bubble lift reactor II, in which the liquid melt is contacted with hydrogen chloride (HCl) at a temperature above 355°C so as to form water, thereby increasing the chloride anions (Cl) compared to the liquid melt obtained according to (a); - )-rich liquid melt is obtained; (c) circulating the liquid melt obtained in (b) to reaction zone iii of a third bubble lift reactor III operated at a temperature in the range of 400-480°C so that chlorine (Cl2) is formed, and Cl2 is removed in gaseous form from reaction zone iii and the third bubble lift reactor III, respectively, resulting in a decrease in Cl2 compared to the liquid melt obtained according to (b); - A liquid melt is left depleted of the [Effects of the Invention]

[0013] Surprisingly, it has been found that this method for preparing chlorine from hydrogen chloride allows for an improved space-time yield in terms of the Cl obtained. The specific temperature ranges used in (a), (b) and (c), especially in (a) and (c), allow for an improved space-time yield in terms of the Cl obtained, and result in an economically advantageous process (small temperature differences between the three reaction zones) since no means for keeping the melt in a liquid, circulatable state, such as an airlift pump and / or pressure differentials, are required. DETAILED DESCRIPTION OF THE INVENTION

[0014] "Copper ion Cu where n is a number in the range of 1 to 2 n+ " is a phrase used by Cu 2+ Cations and Cu 1+ cations, where n is the charge multiplied by 2. 2+ The mole amount (m2) of Cu in the salt mixture multiplied by the charge 1 1+ The total moles (m1) of Cu in the salt mixture 2+and Cu 1+ The total molar amount of Cu 2+ Molar amount of (m1) + Cu 1+ The mole amount (m2) of m1 is divided by the mole amount of m2: n = [m1 × 1 + m2 × 2] / [m1 + m2].

[0015] In one embodiment of the method, the Cl obtained in (c) - The depleted liquid melt is recycled to (a).

[0016] Preferably, n is a number in the range of 1.5 to 2.0, preferably in the range of 1.8 to 2.0, more preferably in the range of 1.9 to 2.0, and more preferably 2, n+ , alkali cations, and chloride ions Cl - and a liquid melt containing the same is used as the initial liquid melt at the start of the process, and the process is initiated in step (c). Reaction zone iii of the third bubble lift reactor III is operated at a temperature in the range of 400 to 480°C, where chlorine (Cl2) is formed, and Cl2 is removed in gaseous form from reaction zone iii and the third bubble lift reactor III, respectively, to reduce Cl2 relative to the initial liquid melt. - A depleted liquid melt is left behind.

[0017] Copper ions Cu n+ , alkali cations, and chloride ions Cl - In the case of a liquid melt containing Cu, the alkali cations preferably include one or more alkali cations selected from the group consisting of lithium cations, sodium cations and potassium cations, and more preferably at least potassium cations. n+ and potassium ions K + and chloride ions Cl - and a molar ratio of Cu in the range of 1:0.60 to 1:1.45, preferably in the range of 1:0.60 to 1:1.40, more preferably in the range of 1:0.77 to 1:1.20, and more preferably in the range of 1:0.85 to 1:1.11. n+ :K +Preferably, the salt mixture is obtained or obtainable from a salt mixture comprising Cu(II)Cl and KCl. The lower the amount of KCl, the higher the amount of CuCl can be, and the higher the Cl yield of the overall process, i.e., the higher the space-time yield.

[0018] According to (a), copper ions Cu n+ , alkali cations, and chloride ions Cl - and a liquid melt containing Cu in a molar ratio of Cu to Cu in the liquid melt in a reaction zone i of the first bubble lift reactor I. 2+ :Cu + Preferably, in (a), copper ions Cu are contacted with oxygen (O2) at a temperature above 375°C so as to increase the n+ and alkali cations and chloride Cl - The contacting of the liquid melt containing Cu with O2 is carried out by using a gas phase containing oxygen (O2). 2+ :Cu + The phrase "increases" preferably refers to the increase in Cu due to O2. + By oxidation of Cu + Cu from ions 2+ In (a), the liquid melt is preferably contacted with O2 at a temperature of 378°C or higher, more preferably 380°C or higher, more preferably in the range of more than 375 to 480°C, more preferably in the range of 378°C to 480°C, more preferably in the range of 380°C to 420°C, more preferably in the range of 390 to 410°C, more preferably in the range of 395 to 405°C.

[0019] According to (b), the liquid melt obtained in (a) is circulated to reaction zone ii of a second bubble lift reactor II, where the liquid melt is contacted with hydrogen chloride (HCl) at a temperature above 355°C. The contacting with HCl in (b) is preferably carried out using a gas phase containing hydrogen chloride (HCl). Preferably, in (b), the liquid melt is contacted with HCl at a temperature of 358°C or higher, more preferably 360°C or higher, more preferably in the range of from above 355 to 420°C, more preferably in the range of 358 to 420°C, more preferably in the range of 360 to 420°C, more preferably in the range of 380 to 420°C, more preferably in the range of 390 to 410°C, more preferably in the range of 395 to 405°C.

[0020] According to (c), the liquid melt obtained in (b) is circulated to reaction zone iii of a third bubble lift reactor III operated at a temperature in the range of 400 to 480°C so that chlorine (Cl2) is formed, and Cl2 is removed in gaseous form from reaction zone iii and the third bubble lift reactor III, respectively. The removal of Cl2 according to (c) is preferably carried out by contacting the liquid melt in (c) with an inert gas, such as argon or nitrogen. Preferably, (c) is carried out at a temperature in the range of 410 to 440°C, preferably in the range of 415 to 435°C, more preferably in the range of 420 to 430°C.

[0021] According to a preferred embodiment of the method, in (a), the liquid melt is contacted with O2 at a temperature in the range of greater than 375 to 480°C, preferably in the range of 378°C to 480°C, more preferably in the range of 380°C to 420°C, more preferably in the range of 390 to 410°C, more preferably in the range of 395 to 405°C; The contacting with HCl in (b) is carried out at a temperature in the range of greater than 355 to 420°C, preferably in the range of 358 to 420°C, more preferably in the range of 360 to 420°C, more preferably in the range of 380 to 420°C, more preferably in the range of 390 to 410°C, more preferably in the range of 395 to 405°C; The removal of Cl2 by (c) is preferably carried out by contacting the liquid melt in (c) with an inert gas, such as argon, at a temperature in the range of 410 to 440°C, preferably in the range of 415 to 435°C, more preferably in the range of 420 to 430°C.

[0022] According to a more preferred embodiment of the method, in (a) the liquid melt is contacted with O2 at a temperature in the range of 395-405°C, and in (b) the contacting with HCl is carried out at a temperature in the range of 395-405°C, and the removal of Cl2 in (c) is preferably carried out by contacting the liquid melt in (c) with an inert gas, for example argon, at a temperature in the range of 420-430°C.

[0023] Compared to the current state of the art, these preferred embodiments result in a smaller temperature difference (Delta T) between steps (a), (b) and (c), which is in the range of 35°C to 15°C, thereby enabling a process with less heating and cooling requirements compared to prior art processes, thus resulting in energy savings.

[0024] The liquid melt is preferably circulated between bubble lift reactors I, II and III by means of connecting lines.

[0025] Steps (a), (b) and (c) may be carried out in batch mode or continuously, preferably continuously.

[0026] Steps (a), (b) or (c), preferably at least two of (a), (b) and (c), more preferably (a), (b) and (c), are preferably carried out at a pressure in the range of 800-1200 mbar, preferably in the range of 900-1100 bar, more preferably in the range of 980-1030 mbar, most preferably at atmospheric pressure (1013 mbar).

[0027] According to a preferred embodiment of the method, in (a), the liquid melt is contacted with O2 at a temperature in the range of greater than 375 to 480°C, preferably in the range of 378°C to 480°C, more preferably in the range of 380°C to 420°C, more preferably in the range of 390 to 410°C, more preferably in the range of 395 to 405°C; The contacting with HCl in (b) is carried out at a temperature in the range of greater than 355 to 420°C, preferably in the range of 358 to 420°C, more preferably in the range of 360 to 420°C, more preferably in the range of 380 to 420°C, more preferably in the range of 390 to 410°C, more preferably in the range of 395 to 405°C; The removal of Cl in (c) is preferably carried out by contacting the liquid melt in (c) with an inert gas, e.g., argon, at a temperature in the range of 410 to 440°C, preferably in the range of 415 to 435°C, more preferably in the range of 420 to 430°C; (a), (b) or (c), preferably at least two of (a), (b) and (c), more preferably (a), (b) and (c), are carried out at a pressure in the range of 980 to 1030 mbar, most preferably at atmospheric pressure (1013 mbar).

[0028] According to a more preferred embodiment of the method, in (a) the liquid melt is contacted with O2 at a temperature in the range of 395-405°C, and in (b) the contacting with HCl is carried out at a temperature in the range of 395-405°C, and the removal of Cl2 in (c) is preferably carried out by contacting the liquid melt with an inert gas, such as argon, in (c) and is carried out at a temperature in the range of 420-430°C, and (a), (b) or (c), preferably at least two of (a), (b) and (c), more preferably (a), (b) and (c), are carried out at a pressure in the range of 980-1030 mbar, most preferably at atmospheric pressure (1013 mbar).

[0029] Reactor System The present invention further provides a reactor system comprising three bubble lift reactors I, II and III, each bubble lift reactor comprising a reaction zone i, ii and iii; an outlet for liquid melt in the upper region of each bubble lift reactor; and an inlet for liquid melt in the lower region of each bubble lift reactor, the bubble lift reactors I, II and III being connected by connecting lines suitable for the circulation of the liquid melt, so that a) the liquid melt outlet of the first bubble lift reactor I is connected by a connecting line to the liquid melt inlet of the second bubble lift reactor II; b) the liquid melt outlet of the second bubble lift reactor II is connected to the liquid melt inlet of the third bubble lift reactor III by a connecting line; c) Reactor systems in which the liquid melt outlet of the third bubble lift reactor III is connected to the liquid melt inlet of the first bubble lift reactor I by a connecting line.

[0030] Preferably, one of the liquid melt outlets is positioned higher (vertically) than the other two remaining liquid melt outlets, and preferably one of the liquid melt outlets is positioned 5 to 10 mm higher (vertically) than the other two remaining liquid melt outlets.

[0031] "Upper region of the reactor" means the upper part of the reactor starting from the (horizontal) middle of the reactor, including the sides of the reactor in said upper part and the top of the reactor; "lower region of the reactor" means the lower part of the reactor starting from the (horizontal) middle of the reactor, including the sides of the reactor in said lower part and the bottom of the reactor.

[0032] In one embodiment of the reactor system, at least a portion of each of the three bubble lift reactors is surrounded by and in heat transfer contact with an individual heating system. Preferably, the individual heating system surrounds at least a lower portion of each bubble lift reactor, and preferably also surrounds a portion of the connecting lines and each liquid melt inlet. In one embodiment, the individual heating system is a furnace.

[0033] In one embodiment of the reactor system, at least 20% by volume of the reactor system, preferably at least 25% by volume, more preferably at least 30% by volume, and more preferably between 30 and 50% by volume, preferably a portion of the upper section of each of the three bubble lift reactors, is embedded in and in heat transfer contact with a heating medium, which preferably includes a heating means. More preferably, the heating medium surrounds at least a portion of the upper section of each bubble lift reactor where the liquid melt outlet is located and a portion of the connecting lines between the reactors. In one embodiment, the heating medium is a sand bath and the heating means is at least one heating band. Preferably, the at least one heating band is embedded in the sand bath and surrounds the reactors. Preferably, the heating medium has a temperature in the range of 370 to 430°C, preferably in the range of 380 to 420°C, more preferably in the range of 390 to 410°C, and more preferably in the range of 395 to 405°C.

[0034] Immersing the reactor system, preferably at least part of the upper parts of the three bubble lift reactors and their liquid melt outlets and part of the connecting lines, in a heating medium is advantageous because it allows for a reduction in the temperature difference between the inside and outside of the reactor system, e.g., the connecting lines between the three reactors, and improves the fluidity of the liquid melt in the connecting lines. As a result, immersion in a heating medium helps to avoid the need for measures to keep the melt in a liquid and circulatable state, e.g., air lift pumps and / or pressure differences, resulting in an economically advantageous method.

[0035] Preferably, each bubble lift reactor includes a bubble lift column having a gas inlet and a gas outlet in an upper region of the bubble lift reactor, the gas inlet being constructed such that the inlet is located in the upper region of the reactor and a tube extends from the inlet at the top inside the reactor toward the bottom of the reactor, enabling a gas phase feed to be delivered to the lower region of the reactor.

[0036] Preferably, at least 90% by volume of the reactor system is surrounded by a separate heating system and heating medium, such that the lower part of each bubble lift reactor and part of the connecting lines and each liquid melt inlet are surrounded by a separate heating system, and at least part of the upper parts of the three bubble lift reactors and their liquid melt outlets and (the remaining) parts of the connecting lines are surrounded by a heating medium. In this preferred embodiment, only the upper region of each bubble lift reactor, where the gas inlet and gas outlet are located, does not have heating means.

[0037] Preferably, each bubble lift reactor is made of a material independently selected from the group of quartz and ceramic, with the ceramic preferably being selected from the group of silicon carbide (SiC), magnesium spinel oxide (Mg-spinel oxide), Mg—ZrO, particularly magnesia-partially stabilized zirconia (Mg-PSZ), and Y—ZrO, particularly yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP); more preferably, at least one of the three bubble lift reactors is made of quartz, and more preferably, all three bubble lift reactors are made of quartz.

[0038] The present invention further relates to chlorine obtained or obtainable by the above-described process for preparing chlorine from hydrogen chloride.

[0039] Furthermore, the present invention relates to a copper ion Cu, wherein n is a number in the range of 1 to 2. n+ and potassium ions K + and chloride ions Cl - and a salt mixture comprising Cu in a molar ratio ranging from 1:0.60 to 1:1.45, preferably ranging from 1:0.60 to 1:1.40, more preferably ranging from 1:0.77 to 1:1.20, and more preferably ranging from 1:0.85 to 1:1.11. n+ :K +and preferably for use in preparing chlorine from hydrogen chloride, more preferably for use in preparing chlorine from hydrogen chloride using CuCl as a catalyst, and more preferably for use in preparing chlorine from hydrogen chloride using CuCl as a catalyst in a reactor system as described above.

[0040] Furthermore, the present invention relates to a copper ion Cu, wherein n is a number in the range of 1 to 2. n+ and potassium ions K + and chloride ions Cl - and in a molar ratio of Cu in the range of 1:0.60 to 1:1.45, preferably in the range of 1:0.60 to 1:1.40, more preferably in the range of 1:0.77 to 1:1.20, more preferably in the range of 1:0.85 to 1:1.11 n+ :K + for preparing chlorine from hydrogen chloride, preferably using CuCl as a catalyst, more preferably for preparing chlorine from hydrogen chloride using CuCl as a catalyst in a reactor system as described above.

[0041] The present invention is further described by the following embodiments and combinations of embodiments as indicated by their respective dependencies and backward references. In particular, it should be noted that in each instance where the scope of embodiments is mentioned, in the context of a term such as "the method according to any one of embodiments 1 to 4," any embodiment within this scope is expressly disclosed for those skilled in the art, i.e., the wording of this term should be understood by those skilled in the art to be synonymous with "the method according to any one of embodiments 1, 2, 3, and 4." Furthermore, it is expressly pointed out that the following series of embodiments represents a properly structured part of the description directed to the general and preferred aspects of the present invention, rather than a set of claims determining the scope of protection.

[0042] 1. A method for preparing chlorine from hydrogen chloride, comprising the steps of: n+, alkali cations, and chloride ions Cl - and circulating the liquid melt comprising the reaction zones i, ii, and iii in a reactor system comprising three bubble lift reactors I, II, and III, each comprising a reaction zone i, ii, and iii: (a) In the reaction zone i of the first bubble lift reactor I, copper ions Cu n+ , alkali cations, and chloride ions Cl - The liquid melt containing Cu and Cu in the molar ratio 2+ :Cu + The Cu content is increased by contacting the Cu alloy with oxygen (O2) at a temperature above 375°C. 2+ :Cu + A liquid melt with elevated temperature is obtained; (b) circulating the liquid melt obtained in (a) to reaction zone ii of a second bubble lift reactor II, in which the liquid melt is contacted with hydrogen chloride (HCl) at a temperature above 355°C so as to form water, thereby increasing the chloride anions (Cl) compared to the liquid melt obtained according to (a); - )-rich liquid melt is obtained; (c) circulating the liquid melt obtained in (b) to reaction zone iii of a third bubble lift reactor III operated at a temperature in the range of 400-480°C so that chlorine (Cl2) is formed, and Cl2 is removed in gaseous form from reaction zone iii and the third bubble lift reactor III, respectively, resulting in a decrease in Cl2 compared to the liquid melt obtained according to (b); - A depleted liquid melt is left behind.

[0043] 2. Cl obtained in (c) - 2. The method of claim 1, wherein the depleted liquid melt is recycled to (a).

[0044] 3. copper ions Cu, where n is a number in the range of 1.5 to 2, preferably in the range of 1.8 to 2.0, more preferably in the range of 1.9 to 2.0, and more preferably 2; n+ , alkali cations, and chloride ions Cl - 3. The method of claim 1 or 2, wherein a liquid melt comprising:

[0045] 4. Copper ion Cu n+ , alkali cations, and chloride ions Cl - and wherein the liquid melt comprises one or more alkali cations selected from the group consisting of lithium cations, sodium cations, and potassium cations, more preferably at least potassium cations.

[0046] 5. The liquid melt contains Cu n+ and potassium ions K + and chloride ions Cl - and a molar ratio of Cu in the range of 1:0.60 to 1:1.45, preferably in the range of 1:0.60 to 1:1.40, more preferably in the range of 1:0.77 to 1:1.20, and more preferably in the range of 1:0.85 to 1:1.11. n+ :K + 5. The method of embodiment 4, wherein the cation is obtained or obtainable from a salt mixture having the formula:

[0047] 6. The method of any one of the preceding claims, wherein in (a), the liquid melt is contacted with O2 at a temperature of 378°C or greater, preferably 380°C or greater, more preferably in the range of greater than 375 to 480°C, more preferably in the range of 378°C to 480°C, more preferably in the range of 380°C to 420°C, more preferably in the range of 390 to 410°C, more preferably in the range of 395 to 405°C.

[0048] 7. The method of any one of the preceding embodiments, wherein in (b), the liquid melt is contacted with HCl at a temperature of 358°C or greater, preferably 360°C or greater, more preferably in the range of greater than 355 to 420°C, more preferably in the range of 358 to 420°C, more preferably in the range of 360 to 420°C, more preferably in the range of 380 to 420°C, more preferably in the range of 390 to 410°C, more preferably in the range of 395 to 405°C.

[0049] 8. The method of any one of embodiments 1 to 7, wherein (c) is carried out at a temperature in the range of 410 to 440°C, preferably in the range of 415 to 435°C, more preferably in the range of 420 to 430°C.

[0050] 9. The method according to any one of the preceding claims, wherein the liquid melt is circulated between the bubble lift reactors I, II and III by means of connecting lines.

[0051] 10. The method of any one of embodiments 1 to 9, wherein (a), (b) and (c) are carried out in batch mode or continuously, preferably continuously.

[0052] 11. The method of any one of the preceding embodiments, wherein (a), (b) or (c), preferably at least two of (a), (b) and (c), more preferably (a), (b) and (c), is carried out at a pressure in the range of 800 to 1200 mbar, preferably in the range of 900 to 1100 bar, more preferably in the range of 980 to 1030 mbar, and most preferably at atmospheric pressure (1013 mbar).

[0053] 12. A reactor system comprising three bubble lift reactors I, II and III, each bubble lift reactor comprising a reaction zone I, ii and iii, respectively; an outlet for liquid melt in the upper region of each bubble lift reactor; and an inlet for liquid melt in the lower region of each bubble lift reactor, wherein bubble lift reactors I, II and III are connected by connecting lines suitable for the circulation of the liquid melt, so that: d) the liquid melt outlet of the first bubble lift reactor I is connected by a connecting line to the liquid melt inlet of the second bubble lift reactor II; e) the liquid melt outlet of the second bubble lift reactor II is connected to the liquid melt inlet of the third bubble lift reactor III by a connecting line; f) A reactor system in which the liquid melt outlet of the third bubble lift reactor III is connected to the liquid melt inlet of the first bubble lift reactor I by a connecting line.

[0054] 13. The reactor system of embodiment 12, wherein one of the liquid melt outlets is positioned higher (vertically) than the other two remaining liquid melt outlets, preferably 5 to 10 mm higher (vertically) than the other two remaining liquid melt outlets.

[0055] 14. The reactor system of embodiment 12 or 13, wherein at least a portion of each of the three bubble lift reactors is surrounded by and in heat transfer contact with a separate heating system.

[0056] 15. The reactor system according to any one of embodiments 12 to 14, wherein at least 20% by volume of the reactor system, preferably at least 25% by volume, more preferably at least 30% by volume, more preferably between 30 and 50% by volume, preferably at least parts of the three bubble lift reactors and their outlets for the liquid melt, and optionally parts of the connecting lines, are embedded in and in heat transfer contact with the heating medium, and the heating medium preferably comprises the heating means.

[0057] 16. The reactor system of any one of embodiments 12 to 15, wherein each bubble lift reactor comprises a bubble lift column and has a gas inlet and a gas outlet in an upper region of the bubble lift reactor.

[0058] 17. The reactor system of any one of embodiments 12 to 16, wherein each bubble lift reactor is made of a material independently selected from the group of quartz and ceramic, where the ceramic is preferably selected from the group of silicon carbide (SiC), magnesium oxide spinel (Mg spinel oxide), Mg—ZrO2, especially magnesia-partially stabilized zirconia (Mg-PSZ), and Y—ZrO2, especially yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP); more preferably, at least one of the three bubble lift reactors is made of quartz, and more preferably, all three bubble lift reactors are made of quartz.

[0059] 18. Chlorine obtained or obtainable by the method according to any one of embodiments 1 to 11.

[0060] 19. Copper ion Cu where n is a number between 1 and 2 n+ and potassium ions K + and chloride ions Cl - and a salt mixture comprising Cu in a molar ratio ranging from 1:0.60 to 1:1.45, preferably ranging from 1:0.60 to 1:1.40, more preferably ranging from 1:0.77 to 1:1.20, and more preferably ranging from 1:0.85 to 1:1.11. n+ :K + and preferably used to prepare chlorine from hydrogen chloride, more preferably used to prepare chlorine from hydrogen chloride using CuCl as a catalyst, more preferably used to prepare chlorine from hydrogen chloride using CuCl as a catalyst in the reactor system of any one of embodiments 12 to 16.

[0061] 20. Copper ion Cu where n is a number between 1 and 2 n+ and potassium ions K + and chloride ions Cl - and in a molar ratio of Cu in the range of 1:0.60 to 1:1.45, preferably in the range of 1:0.60 to 1:1.40, more preferably in the range of 1:0.77 to 1:1.20, more preferably in the range of 1:0.85 to 1:1.11 n+ :K + 17. Use of a salt mixture having the formula:

[0062] The present invention will be further illustrated by the following Reference Examples, Comparative Examples, and Examples. [Example]

[0063] chemicals

[0064] [Table 1]

[0065] analysis The chlorine (Cl) content was determined by conducting the exhaust gas from each reactor (Example 1) or reactor system (Example 2) via the gas outlet of the bubble lift reactor III through a frit into an Erlenmeyer flask containing 1.0 L of water and 20 ml of a 5 M NaNO solution. The chloride content in the solution was continuously measured by an ISE (ion selective electrode, Cole-Parmer).

[0066] (Reference Example 1): Test reactor for single reaction process (Setting 1) A cylindrical reactor equipped with a gas inlet tube (gas inlet), both made of quartz, was used. The gas inlet was constructed so that the inlet was located in the upper region of the reactor, and the tube extended from the inlet at the top to the bottom of the reactor, delivering the gas phase feed into the lower region of the reactor. The gas outlet was located at the top of the reactor.

[0067] The reactors were filled with the respective salt mixtures as shown below. The gas inlets were then positioned so that their openings were approximately 1 cm above the salt mixture. Ar flow was initiated, and the temperature was raised to melt the salt mixture. The respective gas inlet tubes were then lowered into the liquid melt.

[0068] (Reference Example 2): Reactor system for three-stage continuous testing (Configuration 2) The reactor system includes three individual bubble lift reactors I, II, and III, each of which, in use, contains a molten Cu salt species (copper ions Cu, where n is a number in the range of 1 to 2) that circulates continuously within and between each bubble lift reactor. n+ and potassium ions K + and chloride ions Cl -The system contained a mixture of gases (a liquid melt containing gases and gases), and the individual gases could be fed into and removed from a single reactor (as shown in Figure 1). The bubble lift reactors were all made of quartz and had an inner diameter of 22 mm and a length of 400 mm. In the following, the "bubble lift reactor" will be abbreviated as "reactor." The single reactor setup is shown schematically in Figure 2.

[0069] The three individual reactors I, II, and III were connected to each other by connecting lines that allowed the circulation of melt between the reactors. Each reactor had a liquid melt outlet and a liquid melt inlet. The liquid melt outlet of one reactor was located in its upper region and was connected by a connecting line to the liquid melt inlet in the lower region of the next reactor (as shown in Figure 1; in Figure 1, the gas inlets and outlets of each reactor are represented by simple arrows. Figure 3 shows a schematic top view of the reactor system, and Figure 4 shows a schematic side view of the reactor system).

[0070] In detail, the liquid melt outlet of reactor I was located in the upper region of reactor I and connected to the liquid melt inlet in the lower region of reactor II by a connecting line; the liquid melt outlet in the upper region of reactor II was then connected to the liquid melt inlet in the lower region of reactor III by a connecting line; and the liquid melt outlet in the upper region of reactor III was then connected to the liquid melt inlet in the lower region of reactor I by a connecting line.

[0071] All three reactors I, II, and III had an additional inlet (gas inlet) in their upper region suitable for gas supply and an outlet (gas outlet) at the top of the reactor suitable for discharging gaseous components. The gas inlet was a tube with a diameter of 2 mm. The gas inlet for gas supply was constructed so that the inlet was located in the upper region of the reactor and the tube extended from the inlet at the top towards the bottom of the reactor so that the supplied gas phase could be pumped into the lower region of the reactor. All three reactors were heated separately by furnaces, so that the temperature of each reactor was controlled separately.

[0072] The liquid melt outlet, liquid melt inlet, and all connecting lines between the three reactors, as well as all parts of all three reactors above the furnace, were placed in the same heating medium, a sand bath, and heated by heating bands (as shown in Figure 5). In Figure 4, the heating medium (sand bath) is shown as a rectangle in the upper region, and the individual heating systems (furnaces) are shown as rectangles in the lower region of each reactor (F1 for reactor I, F2 for reactor II, and F3 for reactor III).

[0073] In use, all three reactors were positioned at the same height, with the liquid melt inlets all at the same height. To improve flow between the reactors, the liquid melt outlet of one reactor was positioned 5 to 10 mm higher than the liquid melt outlets of the other two reactors (not shown).

[0074] Example 1 CuCl thermal decomposition in a small reactor (typical of the reaction in reactor III according to Reference Example 2) The thermal decomposition reaction of CuCl was measured in a reactor as described in Reference Example 1 (Setup 1). The reactor had an inner diameter of 9 mm and a length of 300 mm; two different gas inlet tubes were used: one was a ceramic tube with four holes and an inner diameter of 0.5 mm; the other was a quartz inlet tube with an inner diameter of 2 mm, which was heat-treated to reduce the outlet diameter.

[0075] The salt mixture consisted of 36% by mass of anhydrous potassium chloride (KCl) and 64% by mass of anhydrous copper(II) chloride (CuCl). 15 grams of the salt mixture was heated to 370°C in a reactor to form a molten salt ("molten salt" is synonymous with "liquid melt"), which was then further heated to the reaction temperature. The height of the molten salt was 9 cm. 15 sccm (sccm = standard cubic centimeters per minute) of Ar was bubbled through the molten salt. The chlorine production rate was measured with a chloride ISE probe. Using a 0.5 mm inner diameter ceramic tube with four holes, the volumetric flow rate of Cl production was 0.175 mol / m at 450°C. 3When a 2 mm inner diameter quartz injection tube with a heat-treated outlet diameter was used, the volumetric flow rate of Cl2 formation was approximately 0.03 mol / m at 395 °C. 3 ·s.

[0076] Example 2 CuCl Oxidation Reaction (Typical of the Reaction in Reactor I from Reference Example 2) The reactor had an inner diameter of 9 mm and a length of 300 mm, and the reactor settings were as described in Reference Example 1 (Setup 1). The salt mixture consisted of 28% by mass of anhydrous potassium chloride (KCl) and 72% by mass of anhydrous copper(I) chloride (CuCl). 20 grams of the mixed salt was heated to 350°C to form a liquid melt. The height of the molten salt was 15 cm. A gas mixture of 9 sccm O2 and 1 sccm Ar was bubbled into the molten salt through a quartz tube with an inner diameter of 2 mm. The oxygen conversion was 29% at 380°C. When a gas mixture of 16 sccm O2 and 4 sccm Ar was bubbled into the molten salt through a quartz tube with an inner diameter of 2 mm, the oxygen conversion was 22% at 360°C and 14% at 400°C.

[0077] Example 3 Chlorination reaction (typical of the reaction in reactor II according to Reference Example 2) The salt mixture used in the chlorination experiments consisted of 24% by mass anhydrous potassium chloride (KCl), 66% by mass anhydrous copper(II) chloride (CuCl), and 10% by mass anhydrous copper(II) oxide (CuO). The reactor had an inner diameter of 9 mm and a length of 300 mm. The gas injection tube had an inner diameter of 2 mm. The reactor setup was as described in Setup 1. The salt mixture was heated to 350 °C, whereupon KCl and CuCl formed a liquid melt. A gas mixture of 20 sccm O and 3 sccm HCl was bubbled through the molten salt. HCl conversion, measured with a chloride ISE probe, was 97% at 360 °C and 94% at 380 °C.

[0078] Example 4 Circulation reaction in a reactor system The reactor system included three individual bubble lift reactors I, II and III, and the reactor system setup was as described in Reference Example 2 (Setting 2).

[0079] For reactor III, T = 425°C was set as the operating temperature. For reactors I and II, the temperature was set at T = 400°C. The temperatures shown for reactors I, II, and III were those in reaction zones i, ii, and iii. Temperatures were measured inside the furnace approximately midway between the top and bottom of each reactor. The distance between the temperature probe and the reactor wall containing the molten salt was 1-2 mm. OMEGA-Quick Disconnect type thermocouples were used. The T error was estimated to be + / - 0.1°C.

[0080] Initiation Phase A salt mixture was obtained by mixing 36% by mass of anhydrous potassium chloride (KCl) and 64% by mass of anhydrous copper(II) chloride (CuCl). The salt mixture was introduced into an empty reactor (tightly packed to avoid the formation of bubbles). The reactors were closed so that the end of the gas inlet tube was positioned approximately 1 mm above the salt mixture. Argon flow was initiated in reactor III. The temperature in the reactors was increased by 100°C every 20–30 min until the operating temperature of each reactor was reached after 1–2 h, allowing the salt to melt. At the operating temperature, the gas inlet tube was lowered into the liquid melt until a distance of approximately 30 mm remained between the end of the tube and the bottom of the reactor.

[0081] The O2 flow and HCl / Ar flow were started just before the gas inlet tubes were inserted into reactors I and II.

[0082] The pressure in the reactor system was 1 atmosphere (1013 mbar, the system was open to the atmosphere). The gas flow rates of O, HCl, and Ar were each set at 240 ml / min. In the case of HCl, it was generated in situ by bubbling 240 ml / min of argon into a concentrated aqueous HCl solution (360 ml).

[0083] Normal operation stage Compared with the three individual reactors in Examples 1-3, the temperature of the circulating reaction, including all three reactions, was selected to achieve optimal conditions, taking into account the Cl2 deliberation, which increases with increasing temperature, the CuCl2 vaporization, which also increases with increasing temperature, and minimizing the temperature difference between the reaction zones. Therefore, during operation, the temperature of Reactor III was set at T = 425 °C, while the temperatures of Reactors I and II were set at T = 400 °C. O2 was supplied to Reactor I through the gas inlet at a flow rate of 240 ml / min, and a gaseous stream containing O2 was withdrawn from the gas outlet of Reactor I. HCl was supplied to Reactor II, and a gaseous stream containing HCl and water was withdrawn from the gas outlet of Reactor II. Gaseous Ar was delivered to Reactor III at a flow rate of 240 ml / min; the gaseous stream containing Ar and Cl2 was withdrawn from Reactor III through the gas outlet and transferred to a connected Erlenmeyer flask containing 1.0 L of water and 20 ml of a 5 M NaNO3 aqueous solution for analysis.

[0084] Cl2 was continuously formed during an operation time of about 5 hours. Thus, the process of the present invention, which comprises step (a) contacting the liquid melt with O2 in reaction zone i of a first bubble lift reactor I at a temperature above 375°C; step (b) circulating the liquid melt obtained in (a) to reaction zone ii of a second bubble lift reactor II, where the liquid melt is contacted with hydrogen chloride (HCl) at a temperature above 355°C; and step (c) circulating the liquid melt obtained in (b) to reaction zone iii of a third bubble lift reactor III, operated at a temperature in the range of 400 to 480°C, is an advantageous process and a promising candidate for an economical industrial process. [Brief explanation of the drawings]

[0085] [Figure 1]A reactor system is shown, comprising three individual reactors I, II, and III. In use, each reactor contained molten Cu salt species that circulated continuously through the reactor. Inlets and outlets for the liquid melt and for circulating the melt and their respective connecting lines are indicated by arrows on the sides of the reactors and between the reactors; gas inlets and outlets for gaseous components entering and leaving the reactors are shown schematically at the bottom and top of the reactors. Reaction zones I, II, and III of each reactor are not shown. [Figure 2] The configuration of all single reactors I, II, and III is illustrated in more detail for one reactor. The reactor design includes three sections: a main reactor (1), an insert column (2), and an injection tube (3) for introducing gaseous reagents into the reactor system. The main reactor (1) is equipped with a glass joint top with gas inlets and outlets for feeding and removing gaseous reagents and products, and an inlet and outlet for liquid melt (recycle). The insert column (2) separates the area exposed to the bubbles and allows the liquid to flow back into the main reactor through holes embedded in the top. The black arrow (→) in Figure 2 indicates the direction of the melt in a single reactor, i.e., a single bubble lift column. The dotted arrow indicates the direction of gas flow. [Figure 3] 1 shows a schematic top view of the reactor system, with arrows indicating the direction of circulating melt flow. [Figure 4]A schematic side view of the reactor system is shown, with arrows indicating the direction of circulating melt flow. All three reactors I, II, and III are positioned within the heating medium system so that the upper region of each reactor is embedded in the heating medium, and at least a portion of the liquid melt outlet and connecting lines are located within the heating medium (4). All three reactors further include individual heating systems (F1, F2, F3), e.g., furnaces, such that a portion of the lower region of each reactor is surrounded by and in heat transfer contact with the individual heating system. As shown in FIG. 4, each individual heating system (F1, F2, F3) surrounds at least a portion of the lower region of each reactor where the liquid melt inlet is located. Preferably, to improve flow between the reactors (not shown), the liquid melt outlet of one reactor is positioned 5 to 10 mm higher than the liquid melt outlets of the other two reactors. Arrows on the top of each reactor indicate the flow of incoming and outgoing gases. [Figure 5] The arrangement of the upper parts of three bubble lift reactors in a heating medium, here a sand bath, is shown. The upper regions of all three reactors are surrounded by the sand bath, so that the liquid melt outlets and connecting lines are at least partially within the sand bath. The heating bands (5) are wrapped around the outside of the connecting lines in a large horizontal triangle and also wrapped around the inside of the connecting lines in a small horizontal triangle. [Explanation of symbols]

[0086] 1. Main reactor 2 Insert column 3 Injection tube 4 Heating medium / sand bath 5 Heating Bands F1, F2, F3 Individual Heating Systems / Furnaces

Claims

1. A method for preparing chlorine from hydrogen chloride, comprising the steps of: n+ , alkali cations, and chloride ions Cl - and circulating the liquid melt comprising the reaction zones i, ii, and iii in a reactor system comprising three bubble lift reactors I, II, and III, each comprising a reaction zone i, ii, and iii: (a) In the reaction zone i of the first bubble lift reactor I, copper ions Cu n+ , alkali cations, and chloride ions Cl - The liquid melt containing Cu and Cu in the molar ratio 2+ :Cu + Oxygen (O 2 ) in a molar ratio of Cu 2+ :Cu + A liquid melt with elevated temperature is obtained; (b) circulating the liquid melt obtained in (a) to reaction zone ii of a second bubble lift reactor II, in which the liquid melt is contacted with hydrogen chloride (HCl) at a temperature in the range of 395-405°C so as to form water, thereby increasing the chloride anions (Cl) compared to the liquid melt obtained according to (a); - )-rich liquid melt is obtained; (c) The liquid melt obtained in (b) is dissolved in chlorine (Cl 2 and circulating Cl from reaction zone iii and the third bubble lift reactor III, the reaction zone iii being operated at a temperature in the range of 420 to 430°C so as to form Cl. 2 are respectively extracted in gaseous form, and Cl is reduced compared to the liquid melt obtained according to (b). - A depleted liquid melt is left behind.

2. (c) Cl obtained - The method of claim 1, wherein the depleted liquid melt is recycled to (a).

3. copper ions Cu, where n is a number in the range of 1.5 to 2.0, preferably in the range of 1.8 to 2.0, more preferably in the range of 1.9 to 2.0, and more preferably 2; n+ , alkali cations, and chloride ions Cl - 3. The method of claim 1 or 2, wherein a liquid melt comprising:

4. Copper ions Cu n+ , alkali cations, and chloride ions Cl - The liquid melt contains, as alkali cations, one or more alkali cations selected from the group consisting of lithium cations, sodium cations and potassium cations, more preferably at least potassium cations, and the liquid melt is preferably Cu n+ and potassium ions K + and chloride ions Cl - and a molar ratio of Cu in the range of 1:0.60 to 1:1.45, preferably in the range of 1:0.60 to 1:1.40, more preferably in the range of 1:0.77 to 1:1.20, more preferably in the range of 1:0.85 to 1:1.

11. n+ :K + Preferably, Cu(II)Cl 2 4. The method according to claim 1, wherein the SiO 2 is obtained or obtainable from a salt mixture comprising:

5. 5. The method according to any one of claims 1 to 4, wherein (a), (b) and (c) are carried out in batch mode or continuously, preferably continuously.

6. 6. A reactor system for use in the process according to any one of claims 1 to 5, comprising three bubble lift reactors I, II and III, each bubble lift reactor comprising a reaction zone i, ii and iii, respectively, and an outlet for liquid melt in the upper region of each bubble lift reactor; an inlet for liquid melt in the lower region of each bubble lift reactor; and bubble lift reactors I, II and III being connected by connecting lines suitable for the circulation of the liquid melt, so that a) the liquid melt outlet of the first bubble lift reactor I is connected by a connecting line to the liquid melt inlet of the second bubble lift reactor II; b) the liquid melt outlet of the second bubble lift reactor II is connected to the liquid melt inlet of the third bubble lift reactor III by a connecting line; c) the liquid melt outlet of the third bubble lift reactor III is connected to the liquid melt inlet of the first bubble lift reactor I by a connecting line, A reactor system in which one of the liquid melt outlets is positioned (vertically) higher than the other two liquid melt outlets, preferably one of the liquid melt outlets is positioned (vertically) 5 to 10 mm higher than the other two liquid melt outlets.

7. Each bubble lift reactor is made of a material independently selected from the group consisting of quartz and ceramic, the ceramic preferably being silicon carbide (SiC), magnesium oxide spinel (Mg spinel oxide), Mg-ZrO 2 , especially magnesia-partially stabilized zirconia (Mg-PSZ) and Y-ZrO 2 , especially yttria-stabilized tetragonal zirconia polycrystal (Y-TZP); more preferably, at least one of the three bubble lift reactors is made of quartz, more preferably, all three bubble lift reactors are made of quartz.

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