CN113908834B

CN113908834B - Preparation method of aldehyde-removing catalyst and refining method of polyether polyol

Info

Publication number: CN113908834B
Application number: CN202110917925.2A
Authority: CN
Inventors: 周昕志; 范军; 秦承群; 石正阳; 王久龙; 陆国太
Original assignee: Wanhua Chemical Group Co Ltd
Current assignee: Wanhua Chemical Group Co Ltd
Priority date: 2021-08-11
Filing date: 2021-08-11
Publication date: 2023-03-03
Anticipated expiration: 2041-08-11
Also published as: CN113908834A

Abstract

The invention discloses a preparation method of an aldehyde removal catalyst and a refining method of polyether polyol.

Description

Preparation method of aldehyde-removing catalyst and refining method of polyether polyol

Technical Field

The invention relates to a preparation method of a formaldehyde removal catalyst and a refining method of polyether polyol, and belongs to the technical field of polyether polyol refining.

Background

In recent years, polyurethane materials are rapidly developed, widely applied to the fields of buildings, automobiles, clothes and the like, and the market demand is strong, and the market demand of polyether polyol as an important raw material for producing polyurethane is continuously increased. At present, the control of odor of polyurethane materials used in the fields of home furnishings, clothes, automotive interiors and the like is extremely strict, which provides a serious test for the quality of polyether polyol which is an upstream raw material of polyurethane, and polyether polyol with low aldehyde content and even zero aldehyde content needs to be produced. However, in the polyether produced by the conventional potassium hydroxide process, ethylene oxide and propylene oxide are inevitably isomerized into alcohol under a strong alkali condition, and the alcohol is further oxidized into acetaldehyde, propionaldehyde and the like, so that the polyether polyol has high aldehyde content and heavy odor. Compared with the potassium hydroxide catalysis, the content of polyether polyol aldehyde produced by DMC catalysis is reduced, and the requirement of downstream manufacturers is still not met. Therefore, a great deal of work has been done by various large polyether polyol manufacturers to reduce the aldehyde content in polyether polyols.

CN108239277A discloses a method for refining polyether polyol with less volatile organic compounds and less odor, which is characterized in that acid and water are added into a neutralization kettle through a pipeline mixer in three stages, and the neutralization kettle is neutralized, adsorbed, crystallized and filtered to refine crude polyether, but the process flow is complicated and tedious and the aldehyde content in the preparation of polyether polyol is still high; CN108148192A discloses a preparation method of low-odor polyether polyol, which adopts a hydrazine compound to remove aldehyde from polyether polyol, but the hydrazine compound has a pungent odor similar to ammonia, and hydrazine is toxic and has damage effects on skin, eyes and liver; wu Shibin, etc. invents a ceramic tile for removing formaldehyde by using nano TIO2 photocatalysis method to attain the goal of purifying air, but said method is low in formaldehyde removing rate, and the formaldehyde content of the purified air is still about 3 ppm.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a preparation method of a high-activity aldehyde removal catalyst, and the catalyst prepared by the method has an obviously excellent removal effect on aldehydes.

The invention also aims to provide a method for refining polyether polyol, which can obtain low-aldehyde low-color polyether polyol with formaldehyde, acetaldehyde, acrolein and acetone contents of 0, propionaldehyde contents of less than 1ppm and color of less than 10 by refining polyether by using the aldehyde-removing catalyst.

A preparation method of the aldehyde-removing catalyst comprises the following steps:

1) And active carbon loading: adding activated carbon, titanium salt, ferric salt and water into a three-neck flask, stirring, and removing water to obtain the loaded activated carbon.

2) And activating the activated carbon: and activating the loaded activated carbon in an oxygen-containing atmosphere.

Air or oxygen can be selected for activation, preferably, the flow rate of air or oxygen is 50-200mL/min, the activation temperature is 400-800 ℃, the activation time is 4-8h, more preferably, the flow rate of air or oxygen is 100-120mL/min, the activation temperature is 500-600 ℃, and the activation time is 5-6h.

The activated carbon is preferably coconut shell activated carbon.

Preferably, the adding amount of the iron salt is 1-10% of the mass of the activated carbon, and the adding amount of the titanium salt is 5-25% of the mass of the activated carbon.

Preferably, the titanium salt is soluble salt of titanium, preferably titanium tetrachloride and titanium tetrabromide; the iron salt is soluble salt of iron, preferably ferric nitrate and ferric chloride.

Preferably, in the step (1), firstly, heating for 6-8h at 60-80 ℃, evaporating water to dryness, and then carrying out drying treatment; preferably, the mesh number of the activated carbon is 60-100 meshes.

A method for refining polyether polyol, comprising the steps of: adding the aldehyde-removing catalyst into the crude polyether, stirring under the condition of micro oxygen atmosphere and illumination, then stripping with nitrogen, and filtering to prepare the polyether polyol.

Preferably, the stirring time is 30-90min, and the nitrogen stripping time is 60-120min.

Preferably, the amount of the aldehyde removal catalyst is more than 0.1 percent of the mass of the crude polyether, and usually, the amount of the aldehyde removal catalyst is less than 10 percent of the mass of the crude polyether, and preferably 0.1 to 1 percent;

a trace oxygen atmosphere, preferably an oxygen content of 1-10%, more preferably an oxygen content of 1-3%; the lighting conditions include ultraviolet light, incandescent light, natural sunlight, and the like.

Preferably, the purification of the polyether can be carried out at room temperature.

Preferably, the crude polyether is polyether prepared by reacting an initiator and an epoxy compound under the condition of a catalyst.

Preferably, in the preparation of the crude polyether, the reaction temperature is 100-180 ℃. .

The catalyst may be an alkali metal hydroxide, a DMC catalyst, or the like as is common in the art, with a DMC catalyst being preferred.

Preferably, the initiator is a small molecule alcohol, such as glycerol, propylene glycol; the reaction temperature is preferably 120 to 130 ℃.

The aldehyde-removing catalyst can be regenerated and recycled after being used, and the regeneration method comprises the following steps: the used catalyst is taken out, cleaned, dried, purged by nitrogen, activated and taken out for reuse.

Preferably, the drying temperature is 100-150 ℃, the drying time is 12-24h, the activation temperature is 400-600 ℃, and the activation time is 5-7h.

Compared with the prior art, the invention has the following beneficial effects:

(1) The self-made aldehyde-removing catalyst is activated carbon loaded ferrotitanium oxide (Ti) ₅ Fe ₃ O ₁₄ /C) compared to ordinary nano-TIO ₂ The catalyst has the advantages of high catalytic activity and low demand of oxidant (oxygen); the catalytic activity is improved by Fe ³ + introduction, into TI ⁴ + lattice structure, substituted TI ⁴ So as to generate a new hole defect, enhance the catalytic action of Ti absorbing light to generate energy and improve the capability of degrading small molecular aldehyde into inorganic substances; second, fe ³ The introduction of the catalyst enhances the binding capacity of the catalyst and oxygen, is beneficial to the refining of polyether under the condition of trace oxygen content, and ensures that the refined polyether has small chroma and high quality; finally, coconut shell activated carbon is adopted for loading, and the solid catalyst is prepared, so that the recycling of the catalyst is facilitated.

The action mechanism of the aldehyde removal catalyst is as follows:

Ti+hv→h ⁺ +e ^-

h ⁺ +H ₂ O→OH·+H ⁺

Fe+O ₂ →Fe....O ₂

O ₂ +e ^- +H ⁺ →OH·

aldehyde + OH. Cndot. + O ₂ →CO ₂ +H ₂ O

Note: ti is active component titanium, fe is active component iron, hv is illumination, h + is proton, e-is electron, OH & is active hydroxyl radical, fe & O2 is oxygen combined with the active component iron.

(2) After the crude polyether is refined by adopting a self-made formaldehyde-removing catalyst, the contents of the prepared polyether polyol formaldehyde, acetaldehyde, acrolein and acetone can be 0, the content of propionaldehyde can be lower than 1ppm, and the chroma is lower than 10; the aldehyde-removing catalyst has high activity, less oxygen demand, low aldehyde content in the prepared polyether polyol and low chroma.

(3) The catalyst of the invention can be regenerated and reused, thus prolonging the service life of the catalyst and saving the cost.

Detailed Description

Aldehyde content test method: the aldehyde ketone content was measured by LC1100 liquid chromatograph using the principle that carbonyl compound reacts with 2,4-Dinitrophenylhydrazine (DNPH) to produce hydrazone derivatives. And (3) drawing external standard method calibration curves of formaldehyde-DNPH, acetaldehyde-DNPH, propionaldehyde-DNPH, acrolein-DNPH and acetone-DNPH, and establishing a high performance liquid chromatography to determine the content of aldehyde substances in the polyether. And the chromaticity is tested according to GB/T22295-2008.

Examples of preparation of catalysts

Catalyst A: adding 20g of 60-80-mesh coconut shell activated carbon, 15% of titanium tetrachloride by mass of activated carbon, 6.5% of ferric trichloride powder by mass of activated carbon and 150g of deionized water into a 250mL three-neck flask, stirring, heating in a water bath at 80 ℃ for 6 hours, evaporating to remove water, putting into a vacuum drying oven, and drying for 24 hours; and (3) putting the dried solid catalyst into a tubular activation furnace, setting the air flow rate at 100mL/min and the temperature at 600 ℃, activating for 6 hours, cooling to obtain a solid catalyst A, and taking out the solid catalyst A for later use.

Catalyst B: adding 30g of 80-100-mesh coconut shell activated carbon, 25% by mass of titanium tetrabromide powder, 10% by mass of activated carbon, 180g of deionized water into a 250mL three-neck flask, stirring, heating in a water bath at 60 ℃ for 8 hours, evaporating to remove water, putting into a vacuum drying oven, and drying for 24 hours; and (3) taking the dried solid catalyst, putting the dried solid catalyst into a tubular activation furnace, setting the oxygen flow rate at 200mL/min and the temperature at 400 ℃, activating for 8 hours, cooling to obtain a solid catalyst B, and taking out the solid catalyst B for later use.

Catalyst C: adding 40g of 80-100-mesh coconut shell activated carbon, 5% by mass of titanium tetrabromide powder, 1% by mass of ferric trichloride powder and 170g of deionized water into a 250mL three-neck flask, stirring, heating in a water bath at 70 ℃ for 7.5h, evaporating to remove water, putting into a vacuum drying oven, and drying for 24h; and (3) putting the dried solid catalyst into a tubular activation furnace, setting the air flow rate at 50mL/min and the temperature at 800 ℃, activating for 4 hours, cooling to obtain a solid catalyst C, and taking out the solid catalyst C for later use.

Catalyst D: adding 20g of 60-80 mesh coconut shell activated carbon, 15% titanium tetrachloride and 150g of deionized water into a 250mL three-neck flask, stirring, heating in a water bath at 80 ℃ for 6h, evaporating to remove water, putting into a vacuum drying oven, and drying for 24h; and (3) putting the dried solid catalyst into a tubular activation furnace, activating for 6 hours at the temperature of 600 ℃ at the air flow rate of 100mL/min to obtain a solid catalyst, and taking out the solid catalyst and the activated carbon loaded with titanium dioxide for later use.

Preparation of crude polyether polyol: putting 183.5g of glycerol and 5363 g of DMC catalyst 0.3492 into a high-pressure reaction kettle, replacing nitrogen, filling nitrogen to 1bar, carrying out EO/PO mixed feeding, feeding 6830g altogether, keeping the reaction temperature at 125 ℃, aging for 1.5h after the reaction is finished, and removing monomers for 15min to obtain the crude polyether polyol.

And (3) refining polyether:

comparative example 1

Taking 550g of crude polyether, transferring the crude polyether into a refining kettle, adding coconut shell activated carbon, stirring and adsorbing for 1h, stripping for 120min by nitrogen, and filtering to obtain refined polyether polyol, wherein the content and chromaticity of aldehyde are shown in the attached table 1.

Comparative example 2

Comparative example 2 is a method for refining polyether by loading titanium dioxide on activated carbon: taking 550g of crude polyether, transferring the crude polyether into a transparent refining kettle, adding a solid catalyst D and active carbon loaded titanium dioxide, wherein the dosage of the solid catalyst D and the active carbon loaded titanium dioxide is 1 percent of the crude polyether, introducing gas (the oxygen concentration is 10 percent) to normal pressure after nitrogen replacement, starting stirring, irradiating by using natural sunlight for 45min at room temperature, stripping by using nitrogen for 120min, filtering out the catalyst to obtain refined polyether polyol, and testing the aldehyde content and the chromaticity shown in attached table 1.

Example 1

Taking 550g of crude polyether, transferring the crude polyether into a transparent refining kettle, adding an aldehyde-removing catalyst A with the amount of 1% of the mass of the crude polyether, replacing with nitrogen, introducing gas (the oxygen concentration is 10%) to normal pressure, starting stirring, irradiating by using natural sunlight for 45min at room temperature, stripping by using nitrogen for 120min, filtering out the catalyst, and recycling to obtain refined polyether polyol, wherein the tested aldehyde content and chroma are shown in attached table 1.

Example 2

Taking 550g of crude polyether, transferring the crude polyether into a transparent refining kettle, adding an aldehyde-removing catalyst A, wherein the dosage of the aldehyde-removing catalyst A is 0.1 percent of the mass of the crude polyether, introducing gas (the oxygen concentration is 1 percent) to normal pressure after nitrogen replacement, starting stirring, irradiating by adopting ultraviolet light for 60min at room temperature, stripping by adopting nitrogen for 90min, filtering out the catalyst, recycling to obtain refined polyether polyol, and testing the aldehyde content and the chromaticity, wherein the aldehyde content and the chromaticity are shown in attached table 1.

Example 3

Taking 550g of crude polyether, transferring the crude polyether into a transparent refining kettle, adding an aldehyde removal catalyst A, wherein the dosage of the aldehyde removal catalyst A is 0.2 percent of the mass of the crude polyether, after nitrogen replacement, filling gas (the oxygen concentration is 2 percent) to normal pressure, starting stirring, irradiating by using incandescent light for 90min at room temperature, stripping by using nitrogen for 60min, filtering out the catalyst, recycling to obtain refined polyether polyol, and testing the aldehyde content and the chromaticity, wherein the aldehyde content and the chromaticity are shown in attached table 1.

Example 4

Taking 550g of crude polyether, transferring the crude polyether into a transparent refining kettle, adding an aldehyde-removing catalyst B, wherein the dosage is 0.15 percent of the mass of the crude polyether, introducing gas (the oxygen concentration is 5 percent) to normal pressure after nitrogen replacement, starting stirring, irradiating by using natural sunlight for 50min at room temperature, stripping by using nitrogen for 80min, filtering out the catalyst, recycling to obtain refined polyether polyol, and testing the aldehyde content and the chromaticity, wherein the aldehyde content and the chromaticity are shown in attached table 1.

Example 5

Taking 550g of crude polyether, transferring the crude polyether into a transparent refining kettle, adding an aldehyde-removing catalyst C, wherein the dosage of the aldehyde-removing catalyst C is 0.5 percent of the mass of the crude polyether, introducing gas (the oxygen concentration is 3 percent) to normal pressure after nitrogen replacement, starting stirring, irradiating by adopting ultraviolet light for 50min at room temperature, stripping by adopting nitrogen for 100min, filtering out the catalyst, recycling to obtain refined polyether polyol, and testing the aldehyde content and the chromaticity, wherein the aldehyde content and the chromaticity are shown in attached table 1.

Table 1, the polyether polyol aldehyde content and color data for the comparative examples and examples are shown.

Example 6 (catalyst regeneration)

The solid catalyst obtained by filtering in the example 1 is taken, washed by deionized water, dried in an oven at 100 ℃ for 24 hours, put into a tubular cremator, activated in a nitrogen atmosphere at 400 ℃ for 7 hours, taken out, recycled for 20 times according to the polyether refining method in the example 1, and respectively tested for aldehyde content and chromaticity, which is shown in an attached table 2.

Example 7 (catalyst regeneration)

Taking the solid catalyst obtained by filtering in the example 2, washing the solid catalyst by deionized water, drying the solid catalyst in an oven at 150 ℃ for 18h, putting the solid catalyst in a tubular cremator, activating the solid catalyst for 5h at 600 ℃ in a nitrogen atmosphere, taking the solid catalyst out, recycling the solid catalyst for 20 times according to the polyether refining method in the example 1, and respectively testing the aldehyde content and the chromaticity, wherein the aldehyde content and the chromaticity are shown in an attached table 2.

Example 8 (catalyst regeneration)

The solid catalyst obtained by filtering in the example 5 is taken, washed by deionized water, dried in an oven at 130 ℃ for 12 hours, put into a tubular cremator, activated in a nitrogen atmosphere at 500 ℃ for 6 hours, taken out, recycled for 20 times according to the polyether refining method in the example 1, and respectively tested for aldehyde content and chromaticity, which is shown in the attached table 2.

The catalyst is regenerated and applied to the polyether polyol to refine the polyether polyol shown in the attached table 2.

Sample (I)	Circulating for 1 time	Circulating for 5 times	Circulating for 10 times	Circulating for 20 times
					Example 6	0.99/10	2.11/11	2.57/11	3.33/15
Example 7	0.93/9	2.31/10	2.78/13	4.01/15
					Example 8	1.22/9	1.98/13	2.23/17	3.98/17

Note: the data in the figure correspond to: total aldehyde content (ppm)/color.

Claims

1. A refining method of polyether polyol is characterized by comprising the following steps: adding an aldehyde-removing catalyst into the crude polyether, stirring under the condition of trace oxygen atmosphere and illumination, then stripping with nitrogen, and filtering to prepare polyether polyol;

the preparation method of the aldehyde-removing catalyst comprises the following steps:

1) And active carbon loading: adding activated carbon, titanium salt, ferric salt and water into a three-neck flask, stirring, and removing water to obtain loaded activated carbon;

2. The refining method according to claim 1, wherein in the step (2), the activation is performed using air or oxygen.

3. The refining process of claim 2, wherein the flow rate of air or oxygen is 50-200mL/min, the activation temperature is 400-800 ℃, and the activation time is 4-8h.

4. The refining method of claim 3, wherein the flow rate of air or oxygen is 100-120mL/min, the activation temperature is 500-600 ℃, and the activation time is 5-6h.

5. The refining method according to claim 1, wherein the amount of the iron salt added is 1 to 10% by mass of the activated carbon, and the amount of the titanium salt added is 5 to 25% by mass of the activated carbon.

6. The refining method according to claim 1, wherein the titanium salt is a soluble salt of titanium selected from titanium tetrachloride and titanium tetrabromide; the iron salt is soluble salt of iron, and is selected from ferric nitrate or ferric chloride.

7. The refining method of claim 1, wherein in step (1), the mixture is first heated at 60-80 ℃ for 6-8h to dry, and then dried.

8. The refining method according to claim 7, wherein the mesh number of the activated carbon is 60 to 100 mesh.

9. The refining process of claim 1, wherein the stirring time is 30-90min and the nitrogen stripping time is 60-120min.

10. The purification process according to claim 1, wherein the amount of the aldehyde-removing catalyst used is 0.1% by mass or more based on the mass of the crude polyether.

11. The purification process according to claim 10, wherein the amount of the aldehyde-removing catalyst is 10% by mass or less of the crude polyether.

12. The refining process of claim 11, wherein the amount of the aldehyde-removing catalyst is 0.1 to 1% by mass based on the mass of the crude polyether.

13. The purification method according to claim 1, wherein the oxygen content of the oxygen atmosphere is 1 to 10%.

14. The purification method according to claim 13, wherein the oxygen atmosphere contains 1 to 3% of oxygen.

15. The refining method of claim 1, wherein the lighting conditions include ultraviolet light, incandescent light, natural sunlight.

16. The refining method of claim 1, wherein the crude polyether is a polyether prepared by reacting an initiator with an epoxy compound under the presence of a catalyst.

17. The refining method according to claim 1, wherein the reaction temperature in the production of the crude polyether is 100 to 180 ℃.

18. The refining process of claim 16, wherein the catalyst is an alkali metal hydroxide, DMC catalyst.

19. The refining process of claim 18, wherein the catalyst is a DMC catalyst.

20. The purification process of claim 16, wherein the initiator is a small molecule alcohol.

21. The refining process of claim 20, wherein the starter is glycerol or propylene glycol.

22. The refining method of claim 1, wherein the aldehyde-removing catalyst is recycled after use, and the regeneration method comprises the following steps: and taking the used catalyst, cleaning, drying, purging with nitrogen, activating, taking out and reusing.

23. The refining process of claim 22, wherein the drying temperature is 100-150 ℃, the drying time is 12-24 hours, the activation temperature is 400-600 ℃, and the activation time is 5-7 hours.