CN110975891A

CN110975891A - Method for preparing sulfuric acid type solid acid catalyst by using waste salt containing KCl

Info

Publication number: CN110975891A
Application number: CN201911254931.3A
Authority: CN
Inventors: 于荟; 吴莉莉; 唐棣; 潘勇; 王森; 朱超凡
Original assignee: Nanjing Polytechnic Institute
Current assignee: Nanjing Polytechnic Institute
Priority date: 2019-12-10
Filing date: 2019-12-10
Publication date: 2020-04-10

Abstract

The invention belongs to the field of acid type solid acid catalysts, and relates to a method for preparing a sulfuric acid type solid acid catalyst by using waste salt containing KCl. Existing SO₄ ^2‑/M_nO_mThe solid acid catalyst has short service life and is easy to deactivate. In order to solve the above problems, the present invention provides a method for preparing a sulfuric acid type solid acid catalyst from KCl-containing waste salt, comprising the steps of: the first step is as follows: preparation K₂Ti₂O₅Whisker, and the second step: will K₂Ti₂O₅Boiling the crystal whisker in sulfuric acid solution, filtering, washing and drying; the third step: hydrothermal treating the sample obtained in the second step with sulfuric acid solution, filtering, washing and drying to obtain SO₄ ^2‑/TiO₂Solid acid catalyst. Solving the problem of SO₄ ^2‑/TiO₂The solid acid has short service life and easy inactivation. The invention not only obtains the solid acid catalyst with high added value, but also can remove the organic matters in the waste salt through high temperature, and can prepare the solid acid catalyst by further separationAn industrial salt.

Description

Method for preparing sulfuric acid type solid acid catalyst by using waste salt containing KCl

Technical Field

The invention belongs to the field of acid type solid acid catalysts, and relates to a method for preparing a sulfuric acid type solid acid catalyst by using waste salt containing KCl.

Background

SO₄ ^2-/M_nO_mThe solid acid has many advantages, and is widely concerned by researchers at home and abroad. In respect of SO₄ ^2-/M_nO_mThe organic synthesis reaction of the solid acid, particularly the catalytic esterification reaction process of the solid acid, has also achieved better results. However, SO₄ ^2-/M_nO_mThe type solid acid catalyst has the life disadvantage of short service life and is easy to activate.

Disclosure of Invention

1. The technical problem to be solved is as follows:

existing SO₄ ^2-/M_nO_mThe solid acid catalyst has short service life and is easy to deactivate.

2. The technical scheme is as follows:

in order to solve the above problems, the present invention provides a method for preparing a sulfuric acid type solid acid catalyst from KCl-containing waste salt, comprising the steps of: the first step is as follows: preparation K₂Ti₂O₅Whisker, and the second step: will K₂Ti₂O₅Boiling the crystal whisker in sulfuric acid solution, filtering, washing and drying; the third step: hydrothermal treating the sample obtained in the second step with sulfuric acid solution, filtering, washing and drying to obtain SO₄ ^2-/TiO₂Solid acid catalyst.

In the second and third steps, the concentration of the sulfuric acid solution is: 0.5-2 mol/L.

In the second step, the boiling temperature is 100-150 ℃.

In the second step and the third step, washing is performed by deionized water until the pH value is unchanged, and washing is completed.

In the second step, the boiling time is 2-6 h.

In both the second and third steps, the drying temperature is 80-100 ℃.

In the third step, the hydrothermal temperature of the hydrothermal treatment is 120-180 ℃.

In the third step, the hydrothermal time of the hydrothermal treatment is 12-36 h.

In the first step, preparation of K₂Ti₂O₅The method of the crystal whisker comprises the following steps: mixing titanium dioxide precursor with KCl and K₂SO₄Mixing the salt uniformly, adding 1-3% of fluxing agent by mass of the total mass, wherein the fluxing agent is one or two of potassium carbonate, potassium nitrate and boric acid, then roasting at 600-1200 ℃ for 2-10h, then washing with deionized water, and drying at 80-100 ℃ to obtain K₂Ti₂O₅Whiskers in which KCl and K₂SO₄Mass ratio: 0.5-5, titanium dioxide precursor and KCl and K₂SO₄The mass ratio of the mixed salt is as follows: 0.5-5.

The preparation method of the titanium dioxide precursor comprises the following steps: taking tetrabutyl titanate as a raw material, carrying out hydrothermal reaction for 2-6h at the hydrothermal temperature of 80-220 ℃, keeping the temperature for 10-40h, centrifuging, washing with deionized water, and drying at 80-100 ℃ to obtain the titanium dioxide precursor.

3. Has the advantages that:

the invention uses KCl-containing industrial waste salt as molten salt type raw material to carry out TiO₂Synthesis of whiskers and hydrothermal preparation of SO₄ ^2-/TiO₂The solid acid is used for preparing a low-cost solid acid catalyst and a method for cooperatively treating industrial hazardous wastes. The invention not only obtains the solid acid catalyst with high added value, but also can remove the organic matters in the waste salt through high temperature, and can prepare industrial salt if further separation is carried out.

Detailed Description

The present invention will be described in detail below with reference to examples.

Example 1

Will K₂Ti₂O₅The crystal whisker is put into sulfuric acid solution to be boiled, filtered, washed and dried.

Wherein the concentration of the sulfuric acid solution is as follows: 0.5mol/L, boiling temperature: boiling time at 100 ℃: 2h, washing reagent: deionized water, washing conditions: until the pH value is unchanged, and the drying temperature is as follows: 80 ℃.

Then the obtained sample is mixed with sulfuric acid solution waterPreparation of SO by thermal treatment₄ ^2-/TiO₂Filtering, washing and drying the solid acid catalyst to obtain the SO42-/TiO2 solid acid catalyst.

Wherein the concentration of the sulfuric acid solution is as follows: 0.8mol/L, hydrothermal time: 12h, hydrothermal temperature: 150 ℃, washing reagent: deionized water, washing conditions: until the pH value is unchanged, and the drying temperature is as follows: at 90 ℃.

Example 2

Wherein the concentration of the sulfuric acid solution is as follows: 1mol/L, boiling temperature: boiling time at 120 ℃: 4h, washing reagent: deionized water, washing conditions: until the pH value is unchanged, and the drying temperature is as follows: at 90 ℃.

And then carrying out hydrothermal treatment on the obtained sample and a sulfuric acid solution to prepare an SO42-/TiO2 type solid acid catalyst, filtering, washing and drying to obtain the SO42-/TiO2 type solid acid catalyst.

Wherein the concentration of the sulfuric acid solution is as follows: 2mol/L, hydrothermal time: 20h, hydrothermal temperature: 180 ℃, washing reagent: deionized water, washing conditions: until the pH value is unchanged, and the drying temperature is as follows: 80 ℃.

Example 3

Wherein the concentration of the sulfuric acid solution is as follows: 2mol/L, boiling temperature: boiling time at 150 ℃: 6h, washing reagent: deionized water, washing conditions: until the pH value is unchanged, and the drying temperature is as follows: at 100 ℃.

Wherein the concentration of the sulfuric acid solution is as follows: 0.5mol/L, hydrothermal time: 36h, hydrothermal temperature: 120 ℃, washing reagent: deionized water, washing conditions: until the pH value is unchanged, and the drying temperature is as follows: at 100 ℃.

Example 4

Preparation K₂Ti₂O₅The method of the crystal whisker comprises the following steps: mixing titanium dioxide precursor with KCl and K₂SO₄Mixing the salt uniformly, adding 1-3% of fluxing agent by mass of the total mass, wherein the fluxing agent is one or two of potassium carbonate, potassium nitrate and boric acid, then roasting at 600-1200 ℃ for 2-10h, washing with deionized water, and drying at 80-10 DEG CDrying at 0 ℃ to obtain K₂Ti₂O₅Whiskers in which KCl and K₂SO₄Mass ratio: 0.5-5, titanium dioxide precursor and KCl and K₂SO₄The mass ratio of the mixed salt is as follows: 0.5-5.

Example 5

As can be seen from the above examples, the invention adopts inorganic solid wastes containing KCl as raw materials to prepare K by a melting method₂Ti₂O₅Whiskers and further preparation of SO₄ ^2-/TiO₂Solid acid catalyst. In the preparation of TiO₂In the course of whiskers, i.e. at K₂Ti₂O₅Ion exchange with hydrochloric acid to prepare H₂Ti₂O₅In the process, a sulfuric acid solution is used for replacing a hydrochloric acid solution in hydrothermal treatment, and H is prepared under the hydrothermal high-temperature high-pressure condition₂Ti₂O₅In the process, SO is added₄ ^2-Substitution with SO₄ ^2-Can enter into H₂Ti₂O₅The structure of (A) does not run off in the reaction, SO that SO is solved₄ ^2-/TiO₂The solid acid has short service life and easy inactivation.

Although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A method for preparing a sulfuric acid type solid acid catalyst by using KCl-containing waste salt comprises the following steps: the first step is as follows: preparation K₂Ti₂O₅Whisker, and the second step: will K₂Ti₂O₅Placing the crystal whisker in sulfuric acidBoiling in solution, filtering, washing and drying; the third step: hydrothermal treating the sample obtained in the second step with sulfuric acid solution, filtering, washing and drying to obtain SO₄ ^2-/TiO₂Solid acid catalyst.

2. The method of claim 1, wherein: in the second and third steps, the concentration of the sulfuric acid solution is: 0.5-2 mol/L.

3. The method of claim 1, wherein: in the second step, the boiling temperature is 100-150 ℃.

4. The method of claim 1, wherein: in the second step and the third step, washing is performed by deionized water until the pH value is unchanged, and washing is completed.

5. The method of claim 1, wherein: in the second step, the boiling time is 2-6 h.

6. The method of claim 1, wherein: in both the second and third steps, the drying temperature is 80-100 ℃.

7. The method of claim 1, wherein: in the third step, the hydrothermal temperature of the hydrothermal treatment is 120-180 ℃.

8. The method of claim 1, wherein: in the third step, the hydrothermal time of the hydrothermal treatment is 12-36 h.

9. The method of any one of claims 1-8, wherein: in the first step, preparation of K₂Ti₂O₅The method of the crystal whisker comprises the following steps: mixing titanium dioxide precursor with KCl and K₂SO₄Uniformly mixing the salt, adding 1-3% of fluxing agent by mass of the total mass, wherein the fluxing agent is any one of potassium carbonate, potassium nitrate and boric acidOne or two kinds of the above-mentioned materials are calcined at 600-1200 deg.C for 2-10h, then washed with deionized water, dried at 80-100 deg.C to obtain K₂Ti₂O₅Whiskers in which KCl and K₂SO₄Mass ratio: 0.5-5, titanium dioxide precursor and KCl and K₂SO₄The mass ratio of the mixed salt is as follows: 0.5-5.

10. The method of claim 9, wherein: the preparation method of the titanium dioxide precursor comprises the following steps: taking tetrabutyl titanate as a raw material, carrying out hydrothermal reaction for 2-6h at the hydrothermal temperature of 80-220 ℃, keeping the temperature for 10-40h, centrifuging, washing with deionized water, and drying at 80-100 ℃ to obtain the titanium dioxide precursor.