CATALYST FOR PREPARING CHLORINE BY OXIDATION OF HYDROGEN CHLORIDE AND PREPARATION THEREOF

Abstract

The present invention relates to a catalyst for producing chlorine by oxidation of hydrogen chloride and a method for preparing the same. The catalyst comprises a support and active ingredients that comprise 1-20 wt % of copper, 0.01-5 wt % of boron, 0.1-10 wt % of alkali metal element(s), 0.1-15 wt % of one or more rare earth elements, and 0-10 wt % of one or more elements selected from magnesium, calcium, barium, manganese, iron, nickel, cobalt, zinc, ruthenium or titanium based on the total weight of the catalyst. The catalyst is prepared by a two-step impregnation method. Comparing with the available catalysts of the same type, the catalyst according to the present invention has greatly improved conversion and stability.

Claims

1. (canceled)

2. A method for producing chlorine by oxidation of hydrogen chloride comprising: contacting a catalyst comprising a support and metal salts or metal oxides applied thereon with hydrogen chloride under oxidative conditions thereby producing chlorine, wherein the metal salts or metal oxides of the catalyst are loaded onto the support such that the catalyst comprises the following active ingredients: 5-20 wt % of copper, 0.01-5 wt % of boron, 0.1-10 wt % of alkali metal element(s), 0.1-15 wt % of one or more rare earth elements, and 0-10 wt % of one or more elements selected from the group consisting of: magnesium, calcium, barium, manganese, iron, nickel, cobalt, zinc, ruthenium and titanium, based on the total weight of the catalyst, and wherein the metal salts or metal oxides of the copper are prepared from a copper-containing compound, wherein the copper containing compound is one or more soluble salts of copper selected from the group consisting of cupric nitrate, cupric chloride, and cupric acetate.

3. The method according to claim 2, wherein the active ingredients comprise: 5-15 wt % of copper, 0.1-4 wt % of boron, 2-7 wt % of alkali metal element(s), 1-11 wt % of one or more rare earth elements, and 1-8 wt % of one or more elements selected from the group consisting of: magnesium, calcium, barium, manganese, iron, nickel, cobalt, zinc, ruthenium and titanium.

4. The method according to claim 3, wherein the active ingredients comprise: 5-12 wt % of copper, 0.15-3 wt % of boron, 2.5-6 wt % of alkali metal element(s), 2-9 wt % of one or more rare earth elements, and 2-6 wt % of one or more elements selected from the group consisting of: magnesium, calcium, barium, manganese, iron, nickel, cobalt, zinc, ruthenium and titanium.

5. The method according to claim 2, wherein the support comprises one or more of: a molecular sieve, kaolin, diatomite, silica, alumina, titania or zirconia, and the support comprises 60-90 wt % of the total weight of the catalyst.

6. The method according to claim 5, wherein the alkali metal element is lithium, sodium, potassium or cesium.

7. The method according to claim 6, wherein the rare earth element comprises one or more lanthanide elements.

8. The method according to claim 2, wherein the catalyst is made by: (a) preparing a solution by dissolving the copper-containing compound and optionally a compound containing a transition metal other than copper in water, then impregnating a support with the solution, and drying the impregnated support; (b) dissolving a boron-containing compound, an alkali metal-containing compound, an alkaline earth metal-containing compound and a rare earth metal-containing compound in water, then impregnating the dried solid obtained in step (a) therein, and drying the impregnated solid; and (c) calcining the solid obtained in step (b) at a temperature of 450-650° C. for 1-5 h so as to obtain the catalyst.

9. The method according to claim 8, wherein the copper-containing compound is a soluble salt of copper.

10. The method according to claim 8, wherein the compound containing a transition metal other than copper is a soluble salt of manganese, iron, nickel, cobalt, zinc, ruthenium or titanium.

11. The method according to claim 8, wherein the boron-containing compound is a soluble boron compound.

12. The method according to claim 8, wherein the alkali metal-containing compound is a soluble salt of lithium, sodium or potassium.

13. The method according to claim 8, wherein the alkaline earth metal-containing compound is a soluble salt of magnesium, calcium or barium.

14. The method according to claim 8, wherein the rare earth metal-containing compound is a soluble salt of a rare earth element.

15. The method according to claim 8, wherein the copper-containing compound is one or more of: cupric nitrate, cupric chloride or cupric acetate; the boron-containing compound is one or more of: boric acid, sodium borate or potassium borate; the compound containing the transition metal other than copper is one or more of: nitrates, chlorides or acetates of manganese, iron, nickel, cobalt or zinc; the alkali metal-containing compound is one or more of: a chloride, a nitrate, an acetate, a carbonate or a borate of sodium or potassium; the alkaline earth metal-containing compound is one or more of: chlorides, nitrates, acetates, carbonates or borates of magnesium or calcium; and the rare earth metal-containing compound is one or more of: nitrates of cerium, lanthanum, praseodymium or neodymium.

16. The method according to claim 8, wherein the active ingredients comprise: 4-15 wt % of copper, 0.1-4 wt % of boron, 2-7 wt % of alkali metal element(s), 1-11 wt % of one or more rare earth elements, and 1-8 wt % of one or more elements selected from the group consisting of: magnesium, calcium, barium, manganese, iron, nickel, cobalt, zinc, ruthenium and titanium.

17. The method according to claim 16, wherein the active ingredients comprise: 5-12 wt % of copper, 0.15-3 wt % of boron, 2.5-6 wt % of alkali metal element(s), 2-9 wt % of one or more rare earth elements, and 2-6 wt % of one or more elements selected from the group consisting of: magnesium, calcium, barium, manganese, iron, nickel, cobalt, zinc, ruthenium and titanium.

18. The method according to claim 8, wherein the support comprises one or more of: a molecular sieve, kaolin, diatomite, silica, alumina, titania or zirconia, and the support comprises 60-90 wt % of the total weight of the catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0021] The catalyst for oxidation of hydrogen chloride and the preparation method of the catalyst according to the invention are illustrated in detail below, however the present invention is not limited by the following description in any way. In the present invention, the total weight of the catalyst refers to the weight of the final catalyst product.

[0022] According to the catalyst for oxidation of hydrogen chloride provided in the present invention, preferably the catalyst comprises the following active ingredients: 4-15 wt %, more preferably 5-12 wt % of copper; 0.1-4 wt %, more preferably 0.15-3 wt % of boron; 2-7 wt %, more preferably 2.5-6 wt % of alkali metal element(s); 1-11 wt %, more preferably 2-9 wt % of one or more rare earth elements; 1-8wt %, more preferably 2-6 wt % of one or more elements selected from magnesium, calcium, barium, manganese, iron, nickel, cobalt, zinc, ruthenium and titanium; as well as 60-90 wt %, preferably 60-85 wt % of a support.

[0023] In the catalyst according to the invention, the alkali metal element is any one selected from lithium, sodium, potassium and cesium, preferably is sodium or potassium. The rare earth element is at least one selected from lanthanide elements, preferably is one or more selected from cerium, lanthanum, praseodymium and neodymium.

[0024] The support according to the invention is at least one selected from molecular sieve, kaolin, diatomite, silica, alumina, titania and zirconia, preferably is molecular sieve or kaolin, and more preferably is type Y molecular sieve (Y-zeolite).

[0025] According to the preparation method of the catalyst for oxidation of hydrogen chloride of the invention, in steps (1) and (2), the impregnation time preferably lasts 8-16 h and then dried at a temperature of 70-110° C. for 12-24 h.

[0026] In the process for preparation of the catalyst, the used copper-containing compound is a soluble salt of copper, preferably one or more selected from cupric nitrate, cupric chloride and cupric acetate. In general, when two or more soluble copper salts are used, they can be combined in any proportions. More preferably, the used copper-containing compounds are cupric nitrate and cupric chloride.

[0027] The compound containing a transition metal other than copper is selected from soluble salts of manganese, iron, nickel, cobalt, zinc, ruthenium and titanium, preferably one or more selected from corresponding nitrates, chlorides and acetates of manganese, iron, nickel, cobalt, zinc and titanium, and more preferably one or more of corresponding nitrates, chlorides and acetates of manganese, iron, cobalt and zinc.

[0028] The boron-containing compound is one or two or three of boric acid, sodium borate and potassium borate. The alkali metal compound is one or more selected from chlorides, nitrates, acetates, carbonates and borates of lithium, sodium, potassium, preferably one or more selected from chloride, nitrate, acetate, carbonate and borate of sodium or potassium. The alkaline earth metal compound is one or more selected from chlorides, nitrates, acetates, carbonates and borates of magnesium, calcium and barium, and preferably one or more selected from chlorides, nitrates, acetates, carbonates and borates of magnesium and calcium. The rare earth metal compound is one or more selected from nitrates and chlorides of cerium, lanthanum, praseodymium and neodymium, preferably one or more selected from the nitrates.

[0029] The catalyst of the invention is useful in the reaction for producing chlorine by catalytic oxidation of hydrogen chloride, which may be carried out in a fixed bed reactor or in other reactors suitable for such reactions.

[0030] The reaction conditions for producing chlorine by the oxidation of hydrogen chloride are that: the reaction temperature is 320-460° C., preferably 360-400° C.; the reaction pressure is 0.1-0.6 MPa, preferably 0.1-0.35 MPa; the mole ratio between hydrogen chloride and oxygen is 0.5-9:1, preferably 1-4:1; and the mass space velocity of hydrogen chloride is 0.1-2.5 h.sup.−1, preferably 0.5-2 h.sup.−1.

[0031] The present invention provides the catalyst for producing chlorine by the oxidation of hydrogen chloride, which comprises a support and the metal salts or metal oxides applied thereon. The metal salts or metal oxides are loaded onto the support such that the catalyst comprises: 1-20 wt % of copper, 0.01-5 wt % of boron, 0.1-10 wt % of alkali metal element, 0.1-15 wt % of one or two or more of rare earth elements, >0-10 wt % of one or two or more of magnesium, calcium, barium, manganese, iron, nickel, cobalt, zinc, ruthenium or titanium, each based on the total weight of the catalyst.

[0032] The catalyst and the preparation method thereof according to the invention will be further described in detail with reference to the following Examples. But the present invention is not limited by these Examples in any way. In the following Examples and Comparative Examples, “%” used refers to “wt %” unless specified otherwise.

[0033] The following Examples and Comparative Examples are carried out in a fixed bed reactor. The general reaction procedure is as follows: hydrogen chloride and oxygen are fed into the top of a quartz tube reactor with their pressures respectively controlled by pressure stabilization valves and their flow rates respectively controlled by mass flow controllers, and the gas flows pass the catalyst bed to conduct the reaction after preheated with quartz sands. The reaction product is absorbed by an excess potassium iodide solution, and the amount of resultant chlorine is measured by the iodometric method and the amount of unreacted hydrogen chloride is measured by acid-base titration for calculating the yield of chlorine.

[0034] In addition, in the following Examples and Comparative Examples, the aqueous solution containing active ingredients is slight excess in impregnation steps, and the solid is directly dried after impregnation, thus there is no loss of the active ingredients.

EXAMPLE 1

[0035] In a 40 ml of aqueous solution that contains 26.3 g CuCl.sub.2.2H.sub.2O, 60 g of HY molecular sieve (rare earth HY molecular sieve, manufactured by Mingmeiyoujie Mining Co. Ltd., Mingguang City, the same below) is impregnated for 12 h, then dried at 90° C. for 16 h. The resultant solid is re-dispersed in a 50 ml of aqueous solution that contains 0.92 g H.sub.3BO.sub.3, 4.95 g KCl, 8.15 g Ce(NO.sub.3).sub.3.6H.sub.2O and 4.05 g Nd(NO.sub.3).sub.3.6H.sub.2O to perform impregnation for 12 h, then dried at 90° C. for 16 h. The dried solid is calcined at 500° C. for 4 h to obtain 90 g of active catalyst. It is tableted to obtain catalyst granules of 30-60 mesh. 6 g of the catalyst of 30-60 mesh is loaded in a fixed bed reactor to conduct a reaction with of the flow rates of hydrogen chloride and oxygen of 100 ml/min respectively, with the reaction temperature at 380° C. and the reaction pressure at 0.18 MPa. After 4 h of reaction, the chlorine yield is 88.6%; and after 100 h of reaction, the chlorine yield is 89.0%. The activity of the catalyst is stable. After 1000 h of reaction, the chlorine yield is 87.8%, that is, the catalyst still keeps quite a high activity.

COMPARATIVE EXAMPLE 1

[0036] In a 42 ml of aqueous solution that contains 26.3 g CuCl.sub.2.2H.sub.2O, 60 g HY molecular sieve is impregnated for 12 h, then dried at 90° C. for 16 h. The resultant solid is re-dispersed in a 54 ml of aqueous solution that contains 4.95 g KCl, 8.15 g Ce(NO.sub.3).sub.3.6H.sub.2O and 4.05 g Nd(NO.sub.3).sub.3.6H.sub.2O to perform impregnation for 12 h, then dried at 90° C. for 16 h. After being calcined at 500° C. for 4 h, 90 g of active catalyst is obtained. It is tableted to obtain catalyst granules of 30-60 mesh.

[0037] With the same reaction conditions as in Example 1, the chlorine yield is 88.2% after 4 h of reaction, and is 86.4% after 100 h of reaction. Obviously, the catalyst has a relatively poor stability.

[0038] It can be concluded from the comparison of Example 1 and Comparative Example 1 that the addition of boron element improves the stability of the catalyst.

EXAMPLE 2

[0039] In a 41 ml of aqueous solution that contains 26.3 g CuCl.sub.2.2H.sub.2O, 60 g kaolin is impregnated for 12 h, then dried at 90° C. for 16 h. The resultant solid is re-dispersed in a 49 ml of aqueous solution that contains 1.15 g H.sub.3BO.sub.3, 4.95 g KCl, 8.15 g Ce(NO.sub.3).sub.3.6H.sub.2O and 4.05 g La(NO.sub.3).sub.3.6H.sub.2O to perform impregnation for 12 h, then dried at 90° C. for 16 h. After being calcined at 500° C. for 4 h, 90 g of active catalyst is obtained. It is tableted to obtain catalyst granules of 30-60 mesh. With the same reaction conditions as in Example 1, the chlorine yield is 86.1% after 4 h of reaction and is 85.8% after 100 h of reaction. The activity of the catalyst substantially remains unchanged. After 1000 h of reaction, the catalyst still keeps its activity with the chlorine yield of 85.4%.

EXAMPLE 3

[0040] In a 45 ml of aqueous solution that contains 17.8 g CuCl.sub.2.2H.sub.2O and 11.5 g Co(NO.sub.3).sub.2.6H.sub.2O, 60 g HY molecular sieve is impregnated for 12 h, then dried at 90° C. for 16 h. The resultant solid is re-dispersed in a 50 ml of aqueous solution that contains 0.46 g H.sub.3BO.sub.3, 4.95 g KCl, 8.15 g Ce(NO.sub.3).sub.3.6H.sub.2O and 4.05 g Pr(NO.sub.3).sub.3.6H.sub.2O to perform impregnation for 12 h, then dried at 90° C. for 16 h. After being calcined at 500° C. for 4 h, 86 g of active catalyst is obtained. It is tableted to obtain catalyst granules of 30-60 mesh. With the same reaction conditions as in Example 1, the chlorine yield is 86.4% after 4 h of reaction and is 86.8% after 100 h of reaction. The catalyst keeps a stable activity. The chlorine yield is 86.0% after 1000 h of reaction.

EXAMPLE 4

[0041] In a 40 ml of aqueous solution that contains 26.3 g CuCl.sub.2.2H.sub.2O, 60 g HY molecular sieve is impregnated for 12 h, then dried at 90° C. for 16 h. The resultant solid is re-dispersed in a 54 ml of aqueous solution that contains 0.92 g H.sub.3BO.sub.3, 3.05 g KCl, 1.35 g Mg(NO.sub.3).sub.2.2H.sub.2O, 8.15 g Ce(NO.sub.3).sub.3.6H.sub.2O and 4.05 g La(NO.sub.3).sub.3.6H.sub.2O to perform impregnation for 12 h, then dried at 90° C. for 16 h. After being calcined at 500° C. for 4 h, 89 g of active catalyst is obtained. It is tableted to obtain catalyst granules of 30-60 mesh.

[0042] In a fixed bed reactor, 6 g of the catalyst prepared in Example 4 is loaded to conduct a reaction with the flow rates of hydrogen chloride and oxygen of 150 ml/min respectively, with the reaction temperature at 383° C. and the reaction pressure at 0.18 MPa. After 4 h of reaction, the chlorine yield is 85.7%, and after 100 h of reaction, is 85.2%. The activity of the catalyst substantially keeps activity. After 1000 h of reaction, the chlorine yield is 85.1%.

COMPARATIVE EXAMPLE 2

[0043] In a 65 ml of aqueous solution that contains 26.3 g CuCl.sub.2.2H.sub.2O, 3.05 g KCl, 1.35 g Mg(NO.sub.3).sub.2 2H.sub.2O, 8.15 g Ce(NO.sub.3).sub.3.6H.sub.2O and 4.05 g La(NO.sub.3).sub.3.6H.sub.2O, 60 g HY molecular sieve is impregnated for 12 h, then dried at 90° C. for 16 h. After being calcined at 550° C. for 4 h, 90 g of active catalyst is obtained. It is tableted to obtain catalyst granules of 30-60 mesh. With the same hydrogen chloride oxidation reaction conditions as in Example 4, the chlorine yield is 82.9% after 4 h of reaction and is 82.0% after 100 h of reaction. The chlorine yield is 80.2% after 1000 h of reaction

[0044] It can be concluded from the comparison between Example 4 and Comparative Example 2 that the catalyst obtained through the two-step impregnation process has a significantly higher activity than that of the catalyst prepared by the one-step impregnation process has. Use of the inventive catalyst in a reaction for production of chlorine by oxidation of hydrogen chloride can increase the chlorine yield by about 3 percent.