Sulfated titanium ferrite oxide, and preparation method and application thereof

Abstract

The application belongs to the technical field of chemical industry, and particularly relates to a sulfated titanium-iron oxide, a preparation method and application thereof. FeCl3 solution is added into an oxidized cellulose aqueous solution, and first mixing and stirring is carried out, then TiCl4 solution is added, second mixing and stirring is carried out, and then ammonia water is added drop by drop into the mixed solution to adjust the pH value to 8.6-9.2; a precipitate is obtained, the precipitate is filtered and washed, and then is immersed in a sulfuric acid solution, and then is fully washed and calcined to obtain the sulfated titanium-iron oxide. The catalyst provided by the application not only has high catalytic effect, but also maintains good catalytic activity and selectivity in the reaction process, and the catalyst can be recycled and reused through an external magnetic field.

Description

Technical Field

[0001] This invention belongs to the field of chemical technology, specifically relating to a sulfated titanium iron oxide, its preparation method, and its application. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Epichlorohydrin is an important organic chemical raw material and fine chemical product, and a major raw material for the preparation of epoxy resins, with a wide range of applications. Epoxy resins made from epichlorohydrin have advantages such as strong adhesion, resistance to chemical corrosion, low shrinkage, good chemical stability, high impact strength, and excellent dielectric properties, and are widely used in coatings, adhesives, reinforcing materials, casting materials, and electronic laminates.

[0004] The preparation of epichlorohydrin from glycerol, a byproduct of biodiesel production, is an important pathway for the high-value utilization of glycerol. The preparation process includes chlorination and cyclization reactions. Chlorination involves the reaction of glycerol with hydrochloric acid at a suitable temperature and with a catalyst, yielding primarily monochloropropanediol and the final product dichloropropanol, with byproducts including organic acid glycerides and glycerol oligomers. Cyclization involves reacting the dichloropropanol produced in the chlorination reaction with an alkaline solution, removing one molecule of hydrogen chloride, and cyclizing to form epichlorohydrin. Highly efficient catalytic chlorination of glycerol to dichloropropanol is an effective way to improve epichlorohydrin conversion and reduce production costs, while the preparation and application of highly efficient catalysts are core technologies for improving reaction performance. Regarding catalyst selection, common catalysts include hydrochloric acid, sulfuric acid, and phosphoric acid. However, these catalysts are not easily recovered, and improper handling can cause environmental pollution and damage. Summary of the Invention

[0005] To overcome the above problems, this invention provides a titanium iron sulfate oxide, its preparation method, and its application. The catalyst provided by this invention not only exhibits high catalytic efficiency, maintaining good catalytic activity and selectivity during the reaction process, but also allows for catalyst recovery and reuse through an external magnetic field.

[0006] A first aspect of the present invention provides a method for preparing titanium iron sulfate oxide, comprising:

[0007] FeCl3 solution was added to the aqueous solution of oxidized cellulose for the first mixing and stirring. Then TiCl4 solution was added for the second mixing and stirring. Ammonia was then added dropwise to the mixed solution to adjust the pH to 8.6-9.2. A precipitate was obtained. The precipitate was filtered, washed, and then immersed in sulfuric acid solution. After thorough washing, it was calcined to obtain sulfated iron titanium oxide.

[0008] In a second aspect, the present invention provides a titanium iron sulfate oxide prepared by the above-described preparation method.

[0009] In a third aspect, the present invention provides the above-mentioned titanium iron sulfate oxide for use in the catalytic chlorination of glycerol to prepare dichloropropanol.

[0010] A fourth aspect of the present invention provides a method for preparing dichloropropanol by chlorination of glycerol, comprising:

[0011] After mixing glycerol and concentrated hydrochloric acid evenly, the sulfated titanium iron oxide described in the second aspect is added, and the mixture is reacted at 110-150°C to generate dichloropropanol.

[0012] The beneficial effects of this invention are as follows:

[0013] (1) Oxidized cellulose molecules contain negatively charged functional groups (carboxyl groups), which attract positively charged metal ions through charge. At the same time, oxidized cellulose molecules are porous materials with a large number of hydroxyl groups on the surface, with a large specific surface area, which can adsorb metal ions. Therefore, oxidized cellulose regulates the distribution and combination of metal elements through charge effect and adsorption effect, which is beneficial to the regulation of the crystal structure and micro-size of titanium iron oxide. The resulting catalyst has high catalytic activity sites, strong magnetism, reasonable pore structure distribution, large specific surface area, can achieve efficient mass transfer and diffusion, and has good stability. It can achieve efficient chlorination of glycerol under mild conditions, with good reaction selectivity, low by-product amount, and improved product yield.

[0014] (2) The reaction equation for the formation of dichloropropanol from the mixture of glycerol and concentrated hydrochloric acid is:

[0015]

[0016] The reaction equations above show that the chlorination of glycerol to prepare dichloropropanol is an ionic substitution reaction. Sulfated titanium iron oxide is acidic and can convert the hydroxyl group of glycerol into a leaving group, promoting the reaction. This is because sulfate has a strong electron-withdrawing effect; the metal atom forms a strong electron-deficient hole due to its empty orbital, thus exhibiting strong Lewis acidity and a strong electron-withdrawing ability. During the catalytic reaction of glycerol with HCl, the metal atom takes electrons from the oxygen atom of the glycerol hydroxyl group, forming a hydroxyl cation. Due to the effect of the hydroxyl cation, CO breaks, further forming a glycerol carbocation. The hydroxyl group on the glycerol molecule is removed and transferred to the Lewis acid center. The carbocation HCl undergoes a nucleophilic reaction, dissociating to release H+. + H + It combines with Lewis acid centers to form protic acids.

[0017] (3) The titanium iron oxide in the catalyst sulfation prepared in this invention includes titanium oxide and iron tetroxide. Iron tetroxide is magnetic, so the catalyst can be recovered and reused by applying an external magnetic field. Detailed Implementation

[0018] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0019] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0020] A first typical embodiment of the present invention provides a method for preparing titanium iron sulfate oxide, comprising:

[0021] FeCl3 solution was added to the aqueous solution of oxidized cellulose for the first mixing and stirring. Then TiCl4 solution was added for the second mixing and stirring. Ammonia was then added dropwise to the mixed solution to adjust the pH to 8.6-9.2. A precipitate was obtained. The precipitate was filtered, washed, and then immersed in sulfuric acid solution. After thorough washing, it was calcined to obtain sulfated iron titanium oxide.

[0022] In one or more embodiments, the degree of polymerization of the oxidized cellulose is 120-320, the degree of oxidation is 0.2-0.5, and the concentration of the oxidized cellulose aqueous solution is 3-4 wt%.

[0023] In one or more embodiments, the concentration of the FeCl3 solution is 0.4–1.0 mol / L.

[0024] In one or more embodiments, the concentration of the TiCl4 solution is 0.5–1.2 mol / L.

[0025] In one or more embodiments, the mass ratio of FeCl3, TiCl4 and oxidized cellulose is 2-3:1.8-2.4:1.

[0026] In one or more embodiments, the first mixing and stirring time is 30 to 60 minutes.

[0027] In one or more embodiments, the second mixing and stirring time is 20 to 40 minutes.

[0028] In one or more embodiments, the precipitate is filtered and then washed until chloride ions are completely removed.

[0029] In one or more embodiments, the concentration of the sulfuric acid solution is 0.9–1.2 mol / L.

[0030] In one or more embodiments, the immersion time is 1 to 1.5 hours.

[0031] In one or more embodiments, the calcination temperature is 430–470°C, and the calcination time is 2–2.5 h.

[0032] A second typical embodiment of the present invention provides a titanium iron sulfate oxide prepared by the above preparation method.

[0033] A third typical embodiment of the present invention provides the above-mentioned titanium iron sulfate oxide for use in the catalytic chlorination of glycerol to prepare dichloropropanol.

[0034] A fourth typical embodiment of the present invention provides a method for preparing dichloropropanol by chlorination of glycerol, comprising:

[0035] After mixing glycerol and concentrated hydrochloric acid evenly, the sulfated titanium iron oxide described in the second aspect is added, and the mixture is reacted at 110-150°C to generate dichloropropanol.

[0036] In one or more embodiments, the concentration of the concentrated hydrochloric acid is 30-35 wt%, preferably 32 wt%.

[0037] Preferably, the volume ratio of the glycerol to the 32wt% concentrated hydrochloric acid is 1:2 to 3.

[0038] In one or more embodiments, the mass ratio of the catalyst to glycerol is 0.5–1.0%:1.

[0039] In one or more embodiments, dichloropropanol is generated by reflux reaction at 110–150°C for 3–9 h.

[0040] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0041] Example 1

[0042] Oxidized cellulose with a degree of polymerization of 240 and an oxidation degree of 0.4 was prepared into a 3.0 wt% aqueous solution. A 0.8 mol / L FeCl3 aqueous solution was added, and the mixture was stirred for 40 min. Then, a 1.0 mol / L TiCl4 solution was added, and the mixture was stirred for 35 min. The mass ratio of FeCl3, TiCl4, and oxidized cellulose was 3:2.4:1. A 30 wt% ammonia solution was then added dropwise to the mixed solution to adjust the pH to 9.2, resulting in a precipitate. The precipitate was filtered and washed until chloride ions were completely removed. The precipitate was then immersed in a 0.9 mol / L sulfuric acid solution for 1.3 h, followed by thorough washing. Finally, the precipitate was calcined at 460 °C for 2.3 h to obtain titanium iron sulfate oxide (Al).

[0043] The prepared catalyst A1 was added to a glycerol chlorination system for catalytic reaction. The volume ratio of glycerol to 32 wt% concentrated hydrochloric acid was 1:2.4. After thorough mixing, catalyst A1 was added, with a mass ratio of catalyst A1 to glycerol of 0.7%:1. The mixture was refluxed at 150°C for 6 hours to produce dichloropropanol. The glycerol conversion rate was 91.2%, and the dichloropropanol yield was 85.4%. In a corresponding conventional reaction system under the same conditions using 2.5% glacial acetic acid as a catalyst, the glycerol conversion rate was 84.2%, and the dichloropropanol yield was 75.1%. Using 2.5% glacial acetic acid as a catalyst resulted in a decrease in conversion rate, product yield, and selectivity.

[0044] Example 2

[0045] Oxidized cellulose with a degree of polymerization of 120 and an oxidation degree of 0.5 was prepared into a 3.2 wt% aqueous solution. A 0.4 mol / L FeCl3 aqueous solution was added, and the mixture was stirred for 50 min. Then, a 1.2 mol / L TiCl4 solution was added, and the mixture was stirred for 40 min. The mass ratio of FeCl3, TiCl4, and oxidized cellulose was 2.2:2.2:1. A 28 wt% ammonia solution was then added dropwise to the mixed solution to adjust the pH to 9.0, resulting in a precipitate. The precipitate was filtered and washed until chloride ions were completely removed. The precipitate was then immersed in a 1.0 mol / L sulfuric acid solution for 1.5 h, followed by thorough washing. Finally, it was calcined at 470 °C for 2.4 h to obtain titanium iron sulfate oxide A2.

[0046] The prepared catalyst A2 was added to a glycerol chlorination system for catalytic reaction. The volume ratio of glycerol to 32 wt% concentrated hydrochloric acid was 1:2.0. After thorough mixing, catalyst A2 was added, with a mass ratio of catalyst A2 to glycerol of 1.0%:1. The mixture was refluxed at 110°C for 3 hours to produce dichloropropanol. The glycerol conversion rate was 90.1%, and the dichloropropanol yield was 83.2%. In a corresponding conventional reaction system, under the same conditions using 2.0% glutaric acid as a catalyst, the glycerol conversion rate was 82.4%, and the dichloropropanol yield was 73.4%. The conversion rate, product yield, and selectivity were all reduced when using 2.0% glutaric acid as a catalyst.

[0047] Example 3

[0048] Oxidized cellulose with a degree of polymerization of 180 and an oxidation degree of 0.2 was prepared into a 3.5 wt% aqueous solution. A 0.5 mol / L FeCl3 aqueous solution was added, and the mixture was stirred for 45 min. Then, a 0.7 mol / L TiCl4 solution was added, and the mixture was stirred for 30 min. The mass ratio of FeCl3, TiCl4, and oxidized cellulose was 2.5:2.0:1. A 30 wt% ammonia solution was then added dropwise to the mixed solution to adjust the pH to 8.9, resulting in a precipitate. The precipitate was filtered and washed until chloride ions were completely removed. The precipitate was then immersed in a 1.1 mol / L sulfuric acid solution for 1.2 h, followed by thorough washing. Finally, the precipitate was calcined at 450 °C for 2.5 h to obtain titanium iron sulfate oxide A3.

[0049] The prepared catalyst A3 was added to a glycerol chlorination system for catalytic reaction. The volume ratio of glycerol to 32 wt% concentrated hydrochloric acid was 1:3.0. After thorough mixing, catalyst A3 was added, with a mass ratio of catalyst A3 to glycerol of 0.6%:1. The mixture was refluxed at 130°C for 8 hours to produce dichloropropanol. The glycerol conversion rate was 93.2%, and the dichloropropanol yield was 84.9%. In a corresponding conventional reaction system, under the same conditions using 2.3% propionic acid as a catalyst, the glycerol conversion rate was 84.9%, and the dichloropropanol yield was 76.2%. The conversion rate, product yield, and selectivity were all reduced when using 2.3% propionic acid as a catalyst.

[0050] Example 4

[0051] Oxidized cellulose with a degree of polymerization of 320 and an oxidation degree of 0.3 was prepared into a 4.0 wt% aqueous solution. A 0.6 mol / L FeCl3 aqueous solution was added, and the mixture was stirred for 30 min. Then, a 0.5 mol / L TiCl4 solution was added, and the mixture was stirred for 25 min. The mass ratio of FeCl3, TiCl4, and oxidized cellulose was 2.0:1.8:1. Ammonia solution with a concentration of 29 wt% was then added dropwise to adjust the pH to 8.6, resulting in a precipitate. The precipitate was filtered and washed until chloride ions were completely removed. The precipitate was then immersed in a 1.2 mol / L sulfuric acid solution for 1.1 h, followed by thorough washing. Finally, the precipitate was calcined at 440 °C for 2.1 h to obtain titanium iron sulfate oxide A4.

[0052] The prepared catalyst A4 was added to a glycerol chlorination system for catalytic reaction. The volume ratio of glycerol to 32 wt% concentrated hydrochloric acid was 1:2.8. After thorough mixing, catalyst A4 was added, with a mass ratio of catalyst A4 to glycerol of 0.5%:1. The mixture was refluxed at 120°C for 9 h to produce dichloropropanol. The glycerol conversion rate was 94.6%, and the dichloropropanol yield was 85.2%. In a corresponding conventional reaction system, under the same conditions using 2.0% glutaric acid as a catalyst, the glycerol conversion rate was 83.4%, and the dichloropropanol yield was 74.1%. The conversion rate, product yield, and selectivity were all reduced when using 2.0% glutaric acid as a catalyst.

[0053] Example 5

[0054] Oxidized cellulose with a degree of polymerization of 200 and an oxidation degree of 0.4 was prepared into a 3.8 wt% aqueous solution. A 1.0 mol / L FeCl3 aqueous solution was added, and the mixture was stirred for 60 min. Then, a 0.9 mol / L TiCl4 solution was added, and the mixture was stirred for 20 min. The mass ratio of FeCl3, TiCl4, and oxidized cellulose was 2.7:1.9:1. A 30 wt% ammonia solution was then added dropwise to adjust the pH to 8.7, resulting in a precipitate. The precipitate was filtered and washed until chloride ions were completely removed. The precipitate was then immersed in a 1.0 mol / L sulfuric acid solution for 1.0 h, followed by thorough washing. Finally, the precipitate was calcined at 430 °C for 2.0 h to obtain titanium iron sulfate oxide A5.

[0055] The prepared catalyst A5 was added to a glycerol chlorination system for catalytic reaction. The volume ratio of glycerol to 32 wt% concentrated hydrochloric acid was 1:2.6. After thorough mixing, catalyst A5 was added, with a mass ratio of catalyst A5 to glycerol of 0.8%:1. The mixture was refluxed at 140°C for 5 hours to produce dichloropropanol. The glycerol conversion rate was 93.5%, and the dichloropropanol yield was 84.9%. The catalyst was recovered and used under the same conditions. After five uses, the glycerol conversion rate was 91.2%, and the dichloropropanol yield was 81.9%, still exhibiting high activity.

Claims

1. A method for preparing titanium iron sulfate oxide for use in the catalytic chlorination of glycerol to dichloropropanol, characterized in that, include: FeCl3 solution was added to the aqueous solution of oxidized cellulose for the first mixing and stirring. Then TiCl4 solution was added for the second mixing and stirring. Ammonia was then added dropwise to the mixed solution to adjust the pH to 8.6-9.

2. The precipitate was obtained, filtered, washed, and then immersed in sulfuric acid solution. After thorough washing, it was calcined to obtain ferrous sulfate oxide. The calcination temperature is 430~470 ℃, and the calcination time is 2~2.5 h.

2. The preparation method according to claim 1, characterized in that, The oxidized cellulose has a degree of polymerization of 120-320, an oxidation degree of 0.2-0.5, and an aqueous solution concentration of 3-4 wt%. The concentration of the FeCl3 solution is 0.4~1.0 mol / L; The concentration of the TiCl4 solution is 0.5~1.2 mol / L.

3. The preparation method according to claim 1, characterized in that, The mass ratio of FeCl3, TiCl4 and oxidized cellulose is 2~3:1.8~2.4:

1.

4. The preparation method according to claim 1, characterized in that, The first mixing and stirring time is 30-60 minutes; The second mixing and stirring time is 20-40 minutes.

5. The preparation method according to claim 1, characterized in that, The concentration of the sulfuric acid solution is 0.9~1.2 mol / L; The soaking time is 1 to 1.5 hours.

6. Titanium iron sulfate oxide prepared by the preparation method according to any one of claims 1 to 5.

7. The titanium iron sulfate oxide of claim 6 is used in the catalytic chlorination of glycerol to prepare dichloropropanol.

8. A method for preparing dichloropropanol by chlorination of glycerol, characterized in that, include: After mixing glycerol and concentrated hydrochloric acid evenly, the sulfated titanium iron oxide of claim 6 is added, and the mixture is reacted at 110~150°C to generate dichloropropanol.

9. The method for preparing dichloropropanol by chlorination of glycerol as described in claim 8, characterized in that, The concentration of the concentrated hydrochloric acid is 30-35 wt%.

10. The method for preparing dichloropropanol by chlorination of glycerol as described in claim 9, characterized in that, The concentration of the concentrated hydrochloric acid is 32 wt%.

11. The method for preparing dichloropropanol by chlorination of glycerol as described in claim 10, characterized in that, The volume ratio of glycerol to 32 wt% concentrated hydrochloric acid is 1:2~3.

12. The method for preparing dichloropropanol by chlorination of glycerol as described in claim 8, characterized in that, The mass ratio of the sulfated titanium iron oxide to glycerol is 0.5~1.0%:1.

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