Method for preparing allyl alcohol by dehydrating glycerol

Abstract

The invention discloses a method for preparing allyl alcohol through glycerol dehydration. In a continuous reactor, a raw material containing hydrogen and a glycerol aqueous solution is contacted and reacted with a catalyst to obtain a product containing allyl alcohol, the catalyst is a metal supported nitrogen coordination doped catalyst. The catalyst is prepared by the following steps: mixing an aqueous solution containing cyanate, a zinc source and a template agent, stirring, filtering, drying, roasting, pickling and drying to obtain the catalyst, according to the method, the glycerol which is cheap and easy to obtain is used as a production raw material for producing high-added-value products, so that the production cost can be effectively reduced. A continuous reactor is adopted for production, and the reaction is carried out under relatively mild reaction conditions; and the heterogeneous catalyst is convenient to separate from the product.

Description

Technical Field

[0001] The present application relates to a method for preparing propylene alcohol by dehydrating glycerol, and belongs to the field of chemistry and chemical engineering. Background Art

[0002] Allyl alcohol, also known as allicinol, is an important chemical intermediate in the production of medicines, pesticides, fragrances and cosmetics. In industry, allyl alcohol is mainly used to produce diallyl phthalate and bis(2,3-dibromopropyl) fumarate. Up to now, the commonly used methods for preparing allyl alcohol in industry can be simply summarized into the following four methods: 1) hydrolysis of allyl chloride; 2) acrolein reduction; 3) propylene oxide isomerization; 4) hydrolysis of allyl acetate. The hydrolysis of allyl chloride was first developed by Shell and Dow Chemical in 1947 and successfully used in the industrial production of allyl alcohol. This method needs to be carried out in an alkaline solution environment of NaOH. Allyl chloride is hydrolyzed to obtain allyl alcohol, accompanied by the production of by-products such as diallyl ether and propionaldehyde. The acrolein reduction method refers to the oxidation of propylene to acrolein under the action of a catalyst, and then the generated acrolein is hydrogenated with ethanol or isopropanol to obtain allyl alcohol. Although this method does not require the use of chlorine in the production process, and the intermediate product acrolein can also be sold as a chemical raw material, making the production cost lower, the separation process of acrolein is relatively complicated, making the investment in equipment relatively large, so this method is only suitable for large-scale production. The propylene oxide isomerization method has become the main method for producing acryl alcohol at present because of its advantages such as simple process, high yield, and less discharge of three wastes. In the production process, propylene oxide is first gasified and preheated, and then sent to a reactor to contact with a lithium phosphate catalyst to isomerize into acryl alcohol. The propylene acetate hydrolysis method was developed and manufactured by Showa Chemical Industry of Japan in 1985. In this method, propylene is acetoxylated to generate propylene acetate, and then hydrolyzed or transesterified to generate acryl alcohol.

[0003] Although the above preparation methods have been implemented in actual industrial production, they all use glycerol, which has a lower raw material cost, as a reactant to prepare propylene alcohol, which has more realistic economic significance. Glycerol, also known as propylene glycol, is a transparent viscous liquid at room temperature and pressure. As a by-product of biodiesel production, about 4 million tons are put on the market every year, which makes the supply of glycerol far greater than the demand. Therefore, converting cheap and readily available glycerol into fine chemical products with high added value has a high industrial development prospect. Summary of the invention

[0004] Based on the analysis of the existing production process of allyl alcohol and the research and judgment of the future market, the present invention optimizes the function of the catalyst to adapt it to a more advantageous chemical process, thereby realizing the continuous production of allyl alcohol, effectively reducing the production cost and increasing the economic benefits.

[0005] According to one aspect of the present application, a method for preparing propenol by dehydrating glycerol is provided, wherein a raw material containing hydrogen and a glycerol aqueous solution is contacted with a catalyst in a continuous reactor to react and obtain a product containing propenol;

[0006] The catalyst is a metal-supported nitrogen-coordinated doped catalyst;

[0007] The catalyst is obtained by the following steps:

[0008] The cyanate-containing aqueous solution, the zinc source and the template are mixed, stirred, filtered, dried, calcined, acid-washed and dried to obtain the catalyst;

[0009] Optionally, the catalyst is obtained by the following steps:

[0010] A zinc source is added to an aqueous solution containing cyanate, stirred I, and then a template is added, stirred II, filtered to obtain a white solid, washed with water and ethanol, dried in air, roasted, acid-washed, filtered and washed again, and dried in air to obtain the catalyst.

[0011] The zinc source is selected from at least one of zinc chloride, zinc gluconate, zinc sulfate and zinc nitrate;

[0012] The cyanate is selected from at least one of cobalt cyanate, ferric cyanate and copper cyanate;

[0013] The template agent is selected from at least one of P123, F127, polyethylene glycol and PVP.

[0014] In the aqueous solution containing cyanate, the concentration of cyanate is 0.1 to 1 M;

[0015] The molar ratio of the zinc source to the cyanate is 10:1 to 1:1;

[0016] The stirring temperature is 30-60°C;

[0017] The stirring time I is 1 to 24 hours;

[0018] The ratio of the template to the substance containing cyanate is 100:1 to 1:1;

[0019] The stirring temperature of II is 1 to 24 hours;

[0020] The stirring time of II is 60-120°C.

[0021] The drying temperature is 60-120°C;

[0022] The drying time is 1 to 24 hours.

[0023] The calcination temperature is 100-1000°C;

[0024] The calcination time is 1 to 24 hours;

[0025] The heating rate of the calcination is 1 to 10°C / min;

[0026] The calcination atmosphere is one of air, nitrogen and oxygen.

[0027] The pickling adopts one of a sulfuric acid solution with a concentration of 0.1 to 1M, a nitric acid solution with a concentration of 0.1 to 1M, and a hydrochloric acid solution with a concentration of 0.1 to 1M;

[0028] The pickling time is 1 to 24 hours;

[0029] The pickling temperature is 30-100°C.

[0030] The drying temperature is 60-120°C;

[0031] The drying time is 1 to 24 hours.

[0032] The space velocity of the raw material is 0.5~5h -1 ;

[0033] In the raw material, the ratio of hydrogen to glycerol in the glycerol aqueous solution is 1 to 20;

[0034] In the raw materials, the concentration of the glycerol aqueous solution is 0.1-1M.

[0035] The reaction temperature is 50-350°C.

[0036] The beneficial effects of this application include:

[0037] The present application uses cheap and readily available glycerol as a production raw material to produce high value-added products, which can effectively reduce production costs. A continuous reactor is used for production, and the reaction is carried out under relatively mild reaction conditions; a multiphase catalyst is easy to separate from the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 NH3-TPD spectra of the catalysts obtained in Examples 1, 2 and 3 of the present application.

[0039] Figure 2 This is the H2-TPD spectrum of the catalyst obtained in Examples 1, 2, and 3 of the present application. DETAILED DESCRIPTION

[0040] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0041] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0042] Example 1

[0043] Dissolve 0.2g potassium hexacyanocobaltate in 20ml deionized water and heat it to 50℃ under vigorous stirring, then slowly add 30ml of aqueous solution containing 0.3g ZnCl2. After vigorous stirring for 1h, add 5g P123 and 10ml tert-butanol and continue stirring for 1h. Wash the filtered white solid with deionized water and ethanol, then place it in air at 120℃ and dry it for 24h. Calcinate the dried solid in a nitrogen environment at 900℃ and a heating rate of 3℃ / min. Place the calcined catalyst in 100ml of 1M sulfuric acid aqueous solution and stir at 50℃ for 24h. Filter and wash the acid-treated catalyst, and dry it at 120℃ in air for 24h. Shape the dried catalyst, load it into a fixed bed reactor, and introduce hydrogen to reduce it at 400℃ for 2h. The temperature of the reactor was then adjusted to 350°C, and a 0.5 M aqueous glycerol solution was introduced to control the space velocity to 1 h. -1 .

[0044] Example 2

[0045] Dissolve 0.3g potassium hexacyanoferrate in 20ml deionized water and heat it to 60℃ under vigorous stirring, then slowly add 30ml of aqueous solution containing 0.5g zinc gluconate. After vigorous stirring for 1h, add 5g F127 and 10ml tert-butyl alcohol, heat to 80℃ and continue stirring for 1h. Wash the filtered white solid three times with deionized water and ethanol, then place it in air at 120℃ and dry it for 24h. Calcinate the dried solid in a nitrogen environment at 800℃, heating rate of 3℃ / min, and maintain for 2h. Place the calcined catalyst in 100ml 0.2M nitric acid aqueous solution and stir at 30℃ for 24h. Filter and wash the acid-treated catalyst three times with deionized water, then dry it at 120℃ in air for 24h. Shape the dried catalyst, load it into a fixed bed reactor, and introduce hydrogen to reduce it at 400℃ for 2h. The temperature of the reactor was then adjusted to 350°C, and a 0.5 M aqueous glycerol solution was introduced to control the space velocity to 1 h. -1 .

[0046] Example 3

[0047] Dissolve 0.2g of potassium tetracyanocuprate in 20ml of deionized water and heat it to 50℃ under vigorous stirring, then slowly add 30ml of an aqueous solution containing 0.5g of zinc sulfate. After vigorous stirring for 1h, add 5g of PVP and 10ml of polyethylene glycol, heat to 80℃ and continue stirring for 1h. Wash the filtered solid three times with deionized water and ethanol, then place it in the air at 120℃ and dry it for 24h. Calcinate the dried solid in a nitrogen environment at 800℃, at a heating rate of 3℃ / min, and maintain for 2h. Place the calcined catalyst in 100ml of 0.2M nitric acid aqueous solution and stir at 30℃ for 24h. Filter and wash the acid-treated catalyst three times with deionized water, then dry it at 120℃ in the air for 24h. Shape the dried catalyst, load it into a fixed bed reactor, and introduce hydrogen to reduce it at 400℃ for 2h. The temperature of the reactor was then adjusted to 350°C, and a 0.5 M aqueous glycerol solution was introduced to control the space velocity to 1 h. -1 .

[0048] Figure 1 This is the NH3-TPD spectrum of the catalyst obtained in Examples 1, 2, and 3 of the present application. Figure 1 It can be seen that there are acidic sites on the surface of the prepared catalyst, which can be used to catalyze the dehydration of glycerol into acrolein.

[0049] Figure 2 The H2-TPD spectra of the catalysts obtained in Examples 1, 2, and 3 of the present application indicate that there are sites for activating hydrogen on the catalyst surface, which can be used for the selective conversion of acrolein to acrylol.

[0050] Table 1 Activity evaluation results in examples

[0051]

[0052] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing propylene alcohol by dehydrating glycerol, characterized in that: In a continuous reactor, a raw material containing hydrogen and a glycerol aqueous solution is contacted with a catalyst to react to obtain a product containing propylene alcohol; The catalyst is a metal-supported nitrogen coordination doped catalyst.

2. The method according to claim 1, characterized in that: The catalyst is obtained by the following steps: The cyanate-containing aqueous solution, the zinc source and the template are mixed, stirred, filtered, dried, calcined, acid-washed and dried to obtain the catalyst; Preferably, the catalyst is obtained by the following steps: The zinc source is added to the aqueous solution containing cyanate, stirred I, and then the template is added, stirred II, filtered to obtain a solid, washed with water and ethanol, dried, roasted, acid washed, filtered and washed again, and dried to obtain the catalyst.

3. The method according to claim 2, characterized in that The zinc source is selected from at least one of zinc chloride, zinc gluconate, zinc sulfate and zinc nitrate; The cyanate is selected from at least one of cobalt cyanate, ferric cyanate and copper cyanate; The template agent is selected from at least one of P123, F127, polyethylene glycol and PVP.

4. The method according to claim 2, characterized in that: In the aqueous solution containing cyanate, the concentration of cyanate is 0.1 to 1 M; The molar ratio of the zinc source to the cyanate is 10:1 to 1:1; The stirring temperature is 30-60°C; The stirring time I is 1 to 24 hours.

5. The method according to claim 2, characterized in that: The molar ratio of the template to the cyanate is 100:1 to 1:1; The stirring temperature of II is 1 to 24 hours; The stirring time of II is 60-120°C.

6. The method according to claim 2, characterized in that The drying temperature is 60-120°C; The drying time is 1 to 24 hours.

7. The method according to claim 2, characterized in that The calcination temperature is 100-1000°C; The calcination time is 1 to 24 hours; The heating rate of the calcination is 1 to 10°C / min; The calcination atmosphere is one of air, nitrogen and oxygen.

8. The method according to claim 2, characterized in that: The pickling adopts one of a sulfuric acid solution with a concentration of 0.1 to 1M, a nitric acid solution with a concentration of 0.1 to 1M, and a hydrochloric acid solution with a concentration of 0.1 to 1M; The pickling time is 1 to 24 hours; The pickling temperature is 30-100°C.

9. The method according to claim 2, characterized in that: The drying temperature is 60-120°C; The drying time is 1 to 24 hours.

10. The method according to claim 1, characterized in that The space velocity of the raw material is 0.5~5h -1 ; In the raw material, the ratio of hydrogen to glycerol in the glycerol aqueous solution is 1 to 20; In the raw material, the concentration of the glycerol aqueous solution is 0.1 to 1 M; The reaction temperature is 50-350°C.

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