CN104557452B - Method for catalyzing one-step hydrogenolysis reaction of glycerol by using nickel-based catalyst - Google Patents

Abstract

The invention relates to a method for using a nickel-based catalyst to catalyze the one-step hydrogenolysis reaction of glycerin. The catalyst is a columnar tablet-type nickel catalyst, the active component is non-noble metal nickel, and the content of nickel is 10% to 50% of the total mass of the catalyst, and the carrier is γ-Al ₂ O ₃ . Under the catalysis of nickel-based catalyst, the reaction temperature is 180~250℃, the concentration of glycerin aqueous solution is 10~80%, the reaction pressure is 0.5~6Mpa, the space velocity of feed liquid is 0.1~1h ^-1 , the catalyst filling height is 40cm, glycerol Highly selective cleavage to 1,2-propanediol.

Description

A kind of method utilizing nickel-based catalyst to catalyze the one-step hydrogenolysis reaction of glycerin

technical field

The invention relates to a method for using a nickel-based catalyst to catalyze the one-step hydrogenolysis reaction of glycerol, in particular to the preparation of a columnar particle nickel-based catalyst and its application in the one-step hydrogenolysis of glycerol to prepare 1,2-propanediol.

technical background

With the increasing depletion of fossil energy, biodiesel has been rapidly developed as a new type of renewable energy. However, about 1 kg of crude glycerol is produced as a by-product for every 9 kg of biodiesel produced. How to effectively use the by-product glycerol has become a research hotspots.

Converting glycerol to other high value-added chemicals such as propylene glycol through high-temperature hydrogenolysis can effectively solve the above problems. Propylene glycol is an important chemical raw material. It has the characteristics of non-toxicity, low boiling point and good polymerization performance. It is widely used in the production of unsaturated polyester, polyurethane resin, etc., and is also widely used in food, cosmetics, medicine and other industries.

Currently, the hydrogenation of glycerol to propylene glycol mainly has the following problems: 1. The use of noble metal catalysts increases investment costs, making it poor in economic performance and lacking in market competitiveness. 2. The catalyst contains metal elements that are harmful to human health and pollute the environment. 3. The catalyst has poor stability and short service life. 4. High temperature and high pressure have high requirements on equipment, which increases the investment cost of equipment. 5. The solvent for dissolving glycerin is a reagent, which increases the cost of production input. 6. Using a tank reactor, the solid-liquid separation is not easy, and the long-term contact between the reaction feed liquid and the catalyst will easily lead to the formation of by-products, reduce the selectivity of the product, and affect the service life of the catalyst. 7. Deliberately pursue the conversion rate of glycerol, while ignoring the selectivity of the target product.

Patent CN102424648B authorizes a method of catalytic hydrogenolysis of glycerol to prepare 1,2-propanediol. This method adopts a kettle reaction, and the solid and liquid are not easy to separate. The long-term contact between the reaction material liquid and the catalyst will easily lead to the formation of by-products, which will affect the use of the catalyst. Life, and the reaction time of this method is too long, which increases the production cost. Patent CN12557872A discloses a method for preparing propylene glycol by one-step hydrogenolysis of glycerin. This method uses ethanol as a solvent, and the reaction time is relatively long, and the production cost is relatively high. Patent CN102731257A discloses a method for selectively preparing propylene glycol from sugar-containing compounds. The reaction pressure of this method is relatively high, the requirements for equipment are high, and the operation process is relatively complicated. CN102924233A discloses a method for preparing propylene glycol by hydrogenolysis of glycerol. The method uses a fixed-bed reactor as the reaction device. The reaction operation is simple and can be produced continuously, but the catalyst used is prepared by coprecipitation and belongs to a supported catalyst. Therefore, although the catalytic efficiency Higher, but the active components are easier to fall off, thus affecting the service life of the catalyst. CN103524302A discloses a process for preparing 1,3-propanediol by hydrogenation of glycerol. The pressure required for the reaction is relatively low, but the reaction time is relatively long, and the catalyst uses a noble metal catalyst, which increases the production cost.

Contents of the invention

Aiming at the above-mentioned problems in the prior art, the present invention provides a method for using a nickel-based catalyst to catalyze the one-step hydrogenolysis reaction of glycerin. Under the action of the catalyst, glycerol can be efficiently hydrogenolyzed.

In order to achieve the above object, the technical scheme that the present invention takes is:

A method for using a nickel-based catalyst to catalyze the one-step hydrogenolysis reaction of glycerin, wherein the nickel-based catalyst is a columnar tablet-type nickel catalyst, the active component is non-noble metal nickel, and the content of nickel is 10-50% of the total mass of the catalyst , the carrier is γ-Al ₂ O ₃ ;

The preparation method of the nickel-based catalyst is as follows: 0.5mol/L~3mol/L nickel nitrate aqueous solution and ammonia water react in a molar ratio of 1:1~1:4 to form a NiOH precipitate, then filter it, dry it, and take it for drying Add γ-Al ₂ O ₃ powder to the final NiOH, the mass ratio of the two is 1:1~1:10, and then add porogen accounting for 1%~10% of the total mass, mix evenly, and press into tablets; High-temperature roasting decomposition, the roasting temperature is 300~800°C, so that NiOH is decomposed into NiO, and finally NiO is pre-reduced with hydrogen, the hydrogen pressure is 0.1~0.2Mpa, the tail gas flow rate is 5~10mL/min, and the heating rate is 20~40 ℃/h, the maximum temperature is 150~250℃, the total reduction time is 5~25h, and the columnar particle nickel-based catalyst is obtained after reduction;

Under the action of the above-mentioned nickel-based catalyst, 1,2-propanediol is generated by hydrocracking the aqueous solution of glycerol in the reaction device. The concentration of the aqueous glycerol solution is 10-80%; the reaction temperature is 180-250°C, and the reaction hydrogen pressure is 0.5- 6Mpa, the space velocity of the feed liquid is 0.1~1h ^-1 , and the filling height of the catalyst in the reaction device is 20~50cm.

Further, the porogen includes: one or one of nitric acid, ethanol, deionized water, methanol, toluene, talcum powder, wood powder, urea, polyurethane (PU), polyvinylpyrrolidone (PVP), and PEG4000 above.

Further, the concentration of the nickel nitrate aqueous solution is preferably 1 to 3 mol/L, the molar ratio of the nickel nitrate aqueous solution to ammonia water is preferably 1:1 to 1:2, and the nickel hydroxide and γ-Al ₂ O ₃ powder The mass ratio is preferably 1:1-1:5, and the mass of the porogen is preferably 1%-5% of the total mass. The calcination temperature is preferably 450-650°C, the highest temperature in the pre-reduction process is preferably 180-220°C, and the total reduction time is preferably 10-20h.

Further, the reaction device is a trickle bed reaction device, the preferred value of the mass concentration of the aqueous glycerin solution is 20% to 60%, and the optimum value is 20% to 50%; The optimal value is 200~220°C, the optimal value of reaction hydrogen pressure is 4~5Mpa, and the optimal value of reaction space velocity is 0.1~0.3h ^-1 .

Further, the filling height of the catalyst bed is 40 cm.

The preparation of 1,2-propanediol by continuous hydrogenolysis on a trickle bed using the columnar particle nickel catalyst of the present invention has the following advantages:

1) The present invention adopts a non-petroleum route, which can effectively alleviate the fossil energy crisis.

2) No noble metal catalyst is used in the catalyst preparation process, and the economic cost is relatively low.

3) The catalytic performance of the catalyst is good, the processing capacity is large, and the catalyst can be recycled for more than half a year.

4) The process does not produce three wastes pollution and achieves zero discharge, which is a green sustainable development route.

5) The trickle bed reactor is adopted, the operation process is simple, and continuous large-scale production can be carried out.

6) The target product has good selectivity and high product quality.

detailed description

The present invention will be described in more detail by examples below, but these examples are not intended to limit the protection scope of the present invention.

Example 1:

First, dissolve nickel nitrate in water to make a 3mol/L solution, then react it with ammonia water at a molar ratio of 1:1.5 to form a NiOH precipitate, then filter it, and dry it for later use. Take the dried nickel hydroxide and add γ-Al ₂ O ₃ powder, the mass ratio is 1:1, mix the two evenly, add methanol, the mass ratio is 1% of the total mass, stir and knead all the substances to make It is mixed evenly and then compressed into tablets. Then carry out high-temperature roasting to decompose NiOH, and the roasting temperature is 650°C. Finally, the calcined catalyst is subjected to hydrogen reduction, the hydrogen pressure is 0.2Mpa, the tail gas flow rate is 10mL/min, the temperature is programmed, the heating rate is 40°C/h, the reduction temperature is 220°C, when the temperature rises to 100°C for 4h, 180°C ℃ for 4 hours, 220 ℃ for 2 hours, the total reduction time is about 15 hours. After the pre-reduction is completed, stop heating, keep the hydrogen pressure of the reaction system above 0.2 MPa, and store the catalyst for use; or inject deionized water into the reaction tube when the temperature is close to room temperature and keep it sealed for use.

Add the catalyst prepared above to the trickle bed reactor so that the bed filling height of the catalyst is 40cm, open the hydrogen cylinder to replace the air 6 times, heat the reaction device, control the temperature at 200°C, feed hydrogen and release the tail gas, and the hydrogen pressure is 4Mpa , use a constant flow pump to inject 50% glycerin aqueous solution into the system with a volume space velocity of 0.1h ^-1 , wait for the reaction feed liquid to reach the space velocity volume, that is, take a sample after 30 minutes of reaction, and use GC for quantitative analysis. The single-pass conversion of glycerol was 83%, and the selectivity of the product 1,2 propanediol was 89%.

Example 2:

First, nickel nitrate was dissolved in water to prepare a 2mol/L solution, and then reacted with ammonia water at a molar ratio of 1:1 to form a NiOH precipitate, which was then filtered and dried for later use. Take the dried nickel hydroxide and add γ-Al ₂ O ₃ powder, the mass ratio is 1:5, mix the two evenly, add methanol, the mass ratio is 5% of the total mass, stir and knead all the substances to make It is mixed evenly and then compressed into tablets. Then carry out high-temperature roasting to decompose NiOH, and the roasting temperature is 450°C. Finally, the calcined catalyst was subjected to hydrogen reduction, the hydrogen pressure was 0.1Mpa, the exhaust gas flow rate was 5mL/min, the temperature was programmed, the heating rate was 20°C/h, and the reduction temperature was 180°C. ℃ for 1h, the total reduction time is about 10h. After the pre-reduction is completed, stop heating, keep the hydrogen pressure of the reaction system above 0.2 MPa, and store the catalyst for use; or inject deionized water into the reaction tube when the temperature is close to room temperature and keep it sealed for use.

Add the catalyst prepared above to the trickle bed reactor so that the bed filling height of the catalyst is 30 cm, open the hydrogen cylinder to replace the air 6 times, heat the reaction device, control the temperature at 210 ° C, feed hydrogen and release the tail gas, and the hydrogen pressure is 4.5 Mpa, use a constant flow pump to inject 30% glycerol aqueous solution into the system with a volume space velocity of 0.2h ^-1 , wait for the reaction feed liquid to reach the space velocity volume, that is, take a sample after 30 minutes of reaction, and use GC for quantitative analysis. The single-pass conversion of glycerol was 88%, and the selectivity of the product 1,2 propanediol was 92%.

Example 3:

First, nickel nitrate was dissolved in water to prepare a 1mol/L solution, and then reacted with ammonia water at a molar ratio of 1:2 to form a NiOH precipitate, which was then filtered and dried for later use. Take the dried nickel hydroxide and add γ-Al ₂ O ₃ powder, the mass ratio is 1:2.5, mix the two evenly, add methanol, the mass ratio is 2.5% of the total mass, stir and knead all the substances to make It is mixed evenly and then compressed into tablets. Then carry out high-temperature roasting to decompose NiOH, and the roasting temperature is 500°C. Finally, the calcined catalyst was subjected to hydrogen reduction, the hydrogen pressure was 0.15Mpa, the exhaust gas flow rate was 7mL/min, the temperature was programmed, the heating rate was 30°C/h, and the reduction temperature was 200°C. ℃ for 4 hours, 200 ℃ for 1 hour, the total reduction time is about 20 hours. After the pre-reduction is completed, stop heating, keep the hydrogen pressure of the reaction system above 0.2 MPa, and store the catalyst for use; or inject deionized water into the reaction tube when the temperature is close to room temperature and keep it sealed for use.

Add the catalyst prepared above to the trickle bed reactor so that the bed filling height of the catalyst is 35cm, open the hydrogen cylinder to replace the air 6 times, heat the reaction device, control the temperature at 220°C, feed hydrogen and release the tail gas, and the hydrogen pressure is 5Mpa , use a constant flow pump to inject 20% glycerol aqueous solution into the system with a volume space velocity of 0.3h ^-1 , wait for the reaction feed liquid to reach the space velocity volume, that is, take a sample after 30 minutes of reaction, and use GC for quantitative analysis. The single-pass conversion of glycerol was 97%, and the selectivity of the product 1,2 propanediol was 77%.

Embodiment 4~8

Control the raw material liquid glycerin to be the same concentration, and the feed volume space velocity is the same value, the implementation requirements are according to Example 1, Table 1 shows the influence of specific reaction conditions temperature and pressure on the preparation of 1,2-propanediol by hydrogenation of glycerin, the single pass of glycerin The conversion and selectivity of the product 1,2-propanediol are as follows.

Table 1 Effect of reaction temperature and pressure on the hydrogenation of glycerol to 1,2-propanediol

Embodiment 9~13

Control raw material liquid glycerin to be the same concentration, and reaction condition temperature and pressure remain uncertain for definite value, implementation requirement is according to embodiment 1, and table 2 is the impact of specific reaction condition feed volume space velocity on glycerol hydrogenation preparation 1,2 propanediol, The per-pass conversion of glycerol and the selectivity of the product 1,2 propanediol are as follows.

Table 2 Effect of feed volume space velocity on hydrogenation of glycerol to 1,2-propanediol

Example Volumetric space velocity (h ^-1 ) Glycerol conversion per pass (%) 1,2 Propanediol selectivity (%) 9 0.18 98 89 10 0.26 89 91 11 0.31 84 93 12 0.36 78 93 13 0.45 71 97

Examples 14~18

Control reaction conditions temperature and pressure and glycerol feed volume space velocity remain indeterminate for definite value, implementation requirement is according to embodiment 1, and table 3 is the impact of specific reaction conditions glycerol feed concentration on glycerol hydrogenation preparation 1,2 propanediol, the glycerol The conversion per pass and the selectivity of the product 1,2 propanediol are as follows.

Table 3 Effect of glycerol feed concentration on the hydrogenation of glycerol to 1,2-propanediol

Example Glycerin concentration (wt%) Glycerol conversion per pass (%) 1,2 Propanediol selectivity (%) 14 20 98 75 15 50 87 90 16 55 82 94 17 58 78 95 18 62 74 96

Claims (5)

1. a method utilizing nickel-based catalyst to catalyze the one-step hydrogenolysis reaction of glycerol, characterized in that: The nickel-based catalyst is a columnar tablet-type nickel catalyst, the active component is non-noble metal nickel, and the content of nickel is 10% to 50% of the total mass of the catalyst, and the carrier is γ-Al ₂ O ₃ ; The preparation method of the nickel-based catalyst is as follows: 0.5mol/L~3mol/L nickel nitrate aqueous solution and ammonia water react in a molar ratio of 1:1~1:4 to form a NiOH precipitate, then filter it, dry it, and take it for drying Add γ-Al ₂ O ₃ powder to the final NiOH, the mass ratio of the two is 1:1~1:10, and then add porogen accounting for 1%~10% of the total mass, mix evenly, and press into tablets; High-temperature roasting decomposition, the roasting temperature is 300~800°C, so that NiOH is decomposed into NiO, and finally NiO is pre-reduced with hydrogen, the hydrogen pressure is 0.1~0.2Mpa, the tail gas flow rate is 5~10mL/min, and the heating rate is 20~40 ℃/h, the maximum temperature is 150~250℃, the total reduction time is 5~25h, and the columnar particle nickel-based catalyst is obtained after reduction; Under the action of the above-mentioned nickel-based catalyst, 1,2-propanediol is generated by hydrocracking the aqueous solution of glycerol in the reaction device. The mass concentration of glycerin aqueous solution is 10-80%; the reaction temperature is 180-250 ° C, and the reaction hydrogen pressure is 0.5 ~6Mpa, the space velocity of the feed liquid is 0.1~1h ^-1 , and the filling height of the catalyst in the reaction device is 20~50cm; The porogen is methanol; The reaction device is a trickle bed reaction device. 2. method according to claim 1, it is characterized in that: the concentration of described nickel nitrate aqueous solution is 1～3mol/L, nickel nitrate aqueous solution and ammoniacal liquor are in molar ratio 1:1～1:2, described nickel hydroxide The mass ratio to the γ-Al ₂ O ₃ powder is 1:1-1:5, and the mass of the porogen is 1%-5% of the total mass. 3. The method according to claim 1, characterized in that: the calcination temperature is 450-650°C, the highest temperature in the pre-reduction process is 180-220°C, and the total reduction time is 10-20h. 4. The method according to claim 1, characterized in that: the mass concentration of the aqueous glycerol solution is 20% to 50%, the temperature of the hydrocracking reaction is 200 to 220°C, the reaction hydrogen pressure is 4 to 5Mpa, and the reaction The space velocity is 0.1~0.3h ^-1 . 5. The method according to claim 1, characterized in that: the filling height of the catalyst bed is 40 cm.