KR101671436B1

KR101671436B1 - Niobium-based catalyst composition for dehydration reaction of glycerol

Info

Publication number: KR101671436B1
Application number: KR1020140178623A
Authority: KR
Inventors: 문동주; 김영철; 이규암
Original assignee: 한국과학기술연구원; 전남대학교산학협력단
Priority date: 2014-12-11
Filing date: 2014-12-11
Publication date: 2016-11-01
Also published as: KR20160071197A

Abstract

The present invention relates to a niobium-based catalyst composition for use in a process for producing acrolein by dehydration of glycerol, a process for producing a niobium-based catalyst using the catalyst composition, and a process for producing acrolein using the niobium-based catalyst.

Description

Niobium-based catalyst composition for dehydration reaction of glycerol [

Acrolein is used as an important intermediate in a wide range of chemical industries, including acrylic acid, methionine, superabsorbent polymers, and detergents.

Acrolein is produced mainly through the partial oxidation of propylene, which is a petrochemical product. This process is greatly influenced by oil prices and releases a large amount of carbon dioxide in the atmosphere, which limits commercial use.

The dehydration reaction of glycerol is known as another production method of acrolein, and is mainly carried out using an acid catalyst. If a liquid acid catalyst (homogeneous catalyst) such as sulfuric acid or phosphoric acid is used as the acid catalyst, separation with the reactant and waste acid treatment must be performed, the catalyst can not be reused, and the reactor may be corroded. As a catalyst for the dehydration reaction of glycerol, a solid acid catalyst (heterogeneous catalyst) is mainly used.

Currently, solid acid catalysts for the dehydration reaction of glycerol are being actively developed. Non-Patent Document 1 discloses a method of producing a crystalline NbPO ₄ solid acid catalyst by using niobium chloride (NbCl ₅ ) and phosphoric acid (H ₃ PO ₄ ), and a method of producing the crystalline NbOPO ₄ _{4 < /} RTI > solid acid catalyst for dehydration of glycerol to produce acrolein. However, the NbPO ₄ solid acid catalyst disclosed in the aforementioned non-patent document 1 can be classified as a crystalline catalyst, which is different from the amorphous catalyst according to the present invention in the preparation method or the catalyst composition.

Korean Patent No. 10-1268459 entitled " Catalyst for acrolein production reaction through dehydration reaction of glycerol and method for producing the same " Korean Patent Laid-Open No. 10-2014-0053209 entitled " Catalyst for the Production of Acrolein and Acrylic Acid by Dehydration of Glycerin and Its Production Method "

"Vapor Phase Dehydration of Glycerol to Acrolein Over NbPO4 catalysts ", J Chem Technol Biotechnol 2014; 89: 1890-897.

An object of the present invention is to provide a catalyst composition for use in acrolein production reaction by dehydration reaction of glycerol.

Another object of the present invention is to provide a method for producing a solid acid catalyst by impregnation.

Still another object of the present invention is to provide a method for producing acrolein by performing a dehydration reaction of glycerol in the presence of the above-mentioned solid acid catalyst.

In order to accomplish the above object, the present invention provides a method of manufacturing a semiconductor device, comprising: (A) a niobium (Nb) precursor; (B) activated carbon; And (C) phosphoric acid (H ₃ PO _4); And a niobium-based catalyst composition for dehydration reaction of glycerol.

(I) adding a niobium (Nb) precursor, activated carbon and phosphoric acid (H ₃ PO ₄ ) to water and stirring the mixture at a temperature of 40 to 60 ° C to prepare a suspension; Ii) drying the suspension at 80 to 120 DEG C to obtain a solid product; And iii) firing and pulverizing the solid product at 300 to 450 ° C in an air atmosphere to obtain an amorphous catalyst; The present invention is directed to a method for producing a niobium catalyst for use in the dehydration reaction of glycerol.

In addition, the present invention is characterized in that acrolein is produced by dehydration reaction of glycerol in the presence of the above-mentioned niobium-based catalyst.

In the present invention, the problem that the specific surface area of the catalyst generated during the production of a conventional solid acid catalyst is reduced can be solved by adding a small amount of activated carbon.

Therefore, the catalyst of the present invention has an increased specific surface area as compared with a conventional solid acid catalyst, thereby being used as a catalyst for dehydration reaction of glycerol which proceeds in a gas phase reaction, thereby improving the stability and performance of the catalyst.

1 is a graph showing the results of XRD analysis of a 0.3P-0.03C-Nb catalyst.
2 is a graph showing the results of FT-IR analysis of a 0.3P-0.03C-Nb catalyst.
3 is a graph showing the results of NH ₃ -TPD analysis of a 0.3P-0.03C-Nb catalyst.
FIG. 4 is a graph comparing catalytic activities of a 0.3P-0.03C-Nb catalyst and a 0.3P-Nb catalyst applied to a glycerol dehydration reaction, respectively.

The present invention relates to a novel solid acid catalyst composition for the production of acrolein by dehydration reaction of glycerol.

The solid acid catalyst composition of the present invention comprises (A) a precursor of an active metal; (B) activated carbon; And (C) phosphoric acid (H ₃ PO _4); .

[catalyst]

(A) an active metal

The solid acid catalyst of the present invention comprises at least one metal element selected from metal elements belonging to groups IIA, IIIA, IIIB, IVA, IVB and VB on the periodic table as active metals. The active metal preferably includes a metal element belonging to the group VB, particularly preferably a niobium (Nb) metal element.

In constituting the catalyst composition of the present invention, the active metal is included in the form of a precursor compound. Specific examples of the precursor of the active metal include niobium halides such as niobium fluoride (NbF ₅ ), niobium chloride (NbCl ₅ ), and niobium bromide (NbBr ₅ ); Niobium alkoxide such as niobium ethoxide; And niobium oxide such as niobium oxide (Nb ₂ O ₅ ) may be used. Among them, niobium oxide (Nb ₂ O ₅ ) in powder form is more preferably used.

(B) Activated carbon

The present invention includes activated carbon as a constituent component of the catalyst composition in order to solve the problem of reduced specific surface area generated during the production of the solid acid catalyst. That is, the phosphoric acid used for preparing the solid acid catalyst covers the active site of the active metal, thereby reducing the surface area of the catalyst. In the present invention, activated carbon is used to control the active site.

Generally, in the field of catalyst production, activated carbon is mainly used as a support and thus used in an excessive amount. In the present invention, a small amount of activated carbon is added as a participating agent for increasing the specific surface area.

The catalyst composition of the present invention contains the activated carbon in an amount of 1 to 5% by weight relative to the weight of the niobium (Nb) metal element contained in the niobium precursor. If the content of the activated carbon is less than 1 wt%, the effect of increasing the specific surface area of the catalyst can not be expected. On the other hand, if the amount of the activated carbon is more than 5 wt%, the acid characteristics of the catalyst are decreased.

(c) Phosphoric acid (H ₃ PO ₄ )

In the present invention, phosphoric acid is included to enhance the acid property of the solid acid catalyst. The phosphoric acid combines with the active metal to increase the amount of acid sites, thereby increasing the selectivity of acrolein. In addition, phosphoric acid is a crystalline solid material and has desirable properties that are well soluble in water solvents used in the production of solid acids.

The catalyst composition of the present invention contains 10 to 50% by weight of the phosphoric acid in terms of the weight of the niobium (Nb) metal element contained in the niobium precursor. If the content of phosphoric acid is less than 10% by weight, the effect of strengthening the acid property of the catalyst is weak, resulting in poor catalytic activity. On the other hand, if the content of phosphoric acid exceeds 50% by weight, Catalyst deactivation is promoted and the selectivity of acrolein is reduced.

[Production method of catalyst]

The present invention features a method for producing a solid acid catalyst based on impregnation. The process for producing a solid acid catalyst according to the present invention comprises the steps of (i) adding a precursor of an active metal, activated carbon and phosphoric acid (H ₃ PO ₄ ) to water and stirring at 40 to 60 ° C to prepare a suspension; Ii) drying the suspension at 80 to 120 DEG C to obtain a solid product; And iii) firing and pulverizing the solid product at 300 to 450 ° C in an air atmosphere to obtain an amorphous catalyst; .

The method for producing the catalyst according to the present invention will be described in more detail as follows.

First, a precursor of activated metal, activated carbon and phosphoric acid (H ₃ PO ₄ ) are added to water at a predetermined content ratio defined above and stirred to obtain a suspension. At this time, the stirring is sufficiently carried out while maintaining the temperature at 40 to 60 ° C.

Then, the suspension is dried to remove the solvent to obtain a solid product. In this case, the drying is carried out at 80 to 120 ° C for 12 to 18 hours, and it is also possible to adjust the drying temperature and time within a range that does not affect catalytic activity for complete drying of the solid product.

Then, the dried solid product is calcined at 300 to 450 ° C for 3 to 4 hours in an air atmosphere. If the calcination temperature is lower than 300 ° C., the catalyst may be subjected to dehydration reaction of glycerol to change the structure of the catalyst during the reaction. If the calcination temperature exceeds 450 ° C., the crystallinity of the active metal may change. As a result, Thereby degrading performance. The fired solid product is pulverized to an average particle size of about 150 to 300 mu m using a ball mill or the like to obtain a powdery solid acid catalyst.

The solid acid catalyst prepared through the above-mentioned production method is an amorphous catalyst (see Fig. 1) and has a specific surface area of 25 to 71 m 2 / g. Considering that the specific surface area of the solid acid catalyst prepared without containing activated carbon is 2.5 to 25 m < 2 > / g as in the following comparative example, the solid acid catalyst of the present invention further contains activated carbon, Able to know.

In addition, the solid acid catalyst of the present invention has NH ₃ -TPD analysis that it is found that acid sites (300 to 400 ° C) useful for the dehydration reaction of glycerol are mainly distributed (see FIG. 3). Therefore, the solid acid catalyst of the present invention is useful as a catalyst for the production of acrolein by dehydration reaction of glycerol.

[Dehydration reaction of glycerol]

The present invention is also characterized in that acrolein is produced by dehydration reaction of glycerol in the presence of the above-mentioned solid acid catalyst.

The dehydration reaction of glycerol according to the present invention proceeds in a vapor phase reaction while flowing a carrier gas. At this time, an inert gas selected from argon (Ar), nitrogen (N ₂ ), helium (He) or the like is used as the carrier gas and flowed at a flow rate of 10 to 20 cc / min

The temperature of the dehydration reaction is suitably 250 to 350 ° C in view of the boiling point of glycerol. When the reaction temperature is lower than 250 ° C, the catalyst life may be shortened due to polymerization or carbonization with glycerol or reaction products. There is a possibility that the selectivity of the desired acrolein may be lowered due to an increase in the concurrent reaction or the sequential reaction.

The pressure of the dehydration reaction is not particularly limited, but it is preferably 10 atm or less, more preferably 5 atm or less under absolute pressure. Under high pressure conditions, the vaporized glycerol may be re-liquefied and the lifetime of the catalyst due to carbon deposition may be shortened.

Glycerol, which is a raw material for the dehydration reaction, is readily available as an aqueous glycerol solution and is fed at a flow rate of 3 to 6 mL / h. At this time, the aqueous glycerin solution may be used in a concentration range of 5 to 90% by weight, preferably 10 to 60% by weight. If the concentration of the glycerol aqueous solution is excessively high, not only does it require a great deal of energy to vaporize glycerol, but also side products are produced.

The present invention will now be described in more detail with reference to the following examples, which should not be construed as limiting the scope of the invention.

[Example]

Examples. Preparation of 0.3P-0.03C-Nb catalyst

2 g of niobia (Nb ₂ O ₅ .nH ₂ O), 0.06 g of activated carbon and 0.6 g of phosphoric acid (H ₃ PO ₄ ) were added to 50 mL of water and vigorously stirred for 4 hours while maintaining the temperature at 50 ° C. The suspension thus obtained was dried at 100 DEG C for 12 hours to remove the water solvent. The solid product obtained through the drying process was calcined in an air atmosphere at 400 ° C. for 3 hours and then pulverized in a ball mill to prepare a powdery catalyst having an average particle size of 200 μm. The catalyst was prepared using 0.03 wt.% Of activated carbon and 0.3 wt.% Of phosphoric acid in terms of the weight of the niobium metal element, and is hereinafter abbreviated as '0.3P-0.03C-Nb catalyst'.

The 0.3P-0.03C-Nb catalyst prepared in the above example had a specific surface area of 62.48 m 2 / g and a total pore volume of 0.0311 cm 3 / g.

In addition, FIG. 1 shows results of XRD analysis of 0.3P-0.03C-Nb catalyst. According to the results of the XRD analysis, the catalyst prepared in the above example was amorphous showing no crystallinity, and activated carbon was uniformly distributed throughout the catalyst.

Comparative Example. Preparation of 0.3P-Nb catalyst

2 g of niobia (Nb ₂ O ₅ .nH ₂ O) and 0.6 g of phosphoric acid (H ₃ PO ₄ ) were added to 50 mL of water and vigorously stirred for 4 hours while maintaining the temperature at 70 ° C. The suspension thus obtained was dried at 100 DEG C for 12 hours to remove the water solvent. The solid product obtained through the drying process was calcined in an air atmosphere at 400 ° C. for 3 hours and then pulverized in a ball mill to prepare a powdery catalyst having an average particle size of 200 μm. The catalyst is prepared by using 0.3 wt% phosphoric acid based on the weight of the niobium metal element, and is hereinafter abbreviated as '0.3P-Nb catalyst'.

FIG. 2 shows results of FT-IR analysis of the catalysts prepared in the above Examples and Comparative Examples. 2, the characteristic peak corresponding to the CP bond due to the interaction between phosphoric acid and activated carbon was observed in the wavelength range of 2200 to 2300 cm ^{-1 in the} 0.3P-0.03C-Nb catalyst of the example.

In addition, FIG. 3 shows results of NH ₃ -TPD analysis of the catalysts prepared in Examples and Comparative Examples. 3 shows that the acidity distribution was broader and the amount of acid sites was larger than that of the 0.3P-0.03C-Nb catalyst of the example and the 0.3P-Nb catalyst of the comparative example, . In the case of the production of acrolein by the gas-phase dehydration reaction of glycerol, as in the case of the 0.3P-Nb catalyst of the comparative example, if the acid strength is too strong, the carbon deposition on the surface of the catalyst is accelerated and the catalytic activity is lowered.

Experimental example. Manufacture of acrolein

0.4 g of each of the catalysts prepared in the above Examples and Comparative Examples was introduced into a quartz reactor having a diameter of 8.8 mm and a glycerol aqueous solution having a concentration of 10% by weight was injected at a rate of 5 mL / h. After the temperature of the reactor was elevated to 310 ° C., glycerol and argon were reacted with 10 cc / min of argon (Ar) gas as a carrier gas in the reactor while the temperature inside the reactor was kept constant at 310 ° C., .

FIG. 4 shows the results of the comparison of catalytic activities in the dehydration reaction of glycerol. 4, it can be seen that the 0.3P-0.03C-Nb catalyst of the example exhibited a higher glycerol conversion and acrolein selectivity than the 0.3P-Nb catalyst of the comparative example. The initial reaction activity of the 0.3P-Nb catalyst of the comparative example was relatively good, but it was confirmed that the catalytic activity rapidly decreased after 4 hours of the reaction time.

Claims

(A) a niobium (Nb) precursor,
(B) 1 to 5% by weight of activated carbon and 10 to 50% by weight of phosphoric acid (H ₃ PO ₄ ) relative to the weight of the niobium (Nb) metal element contained in the niobium precursor Wherein the amorphous niobium solid acid catalyst composition is an amorphous niobium solid acid catalyst composition.

The method according to claim 1,
Wherein the niobium precursor is selected from the group consisting of halides, alkoxides and oxides of niobium (Nb). The amorphous niobium solid acid catalyst composition for use in the dehydration reaction of glycerol.

delete

In water (A) and niobium (Nb) precursor, and, in case the weight of niobium (Nb) metal element contained in the niobium precursor (B) of activated carbon 1-5% by weight of the (C) phosphoric acid _{(H 3 PO 4) 10 ~} 50 % By weight and stirring at a temperature of 40 to 60 DEG C to prepare a suspension;
Drying the suspension at 80 to 120 DEG C to obtain a solid product; And
Calcining and pulverizing the solid product at 300 to 450 캜 in an air atmosphere to obtain an amorphous niobium-based solid acid catalyst;
Wherein the reaction is carried out in the presence of a catalyst to produce an amorphous niobium solid acid catalyst.

6. The method of claim 5,
Wherein the niobium (Nb) precursor is selected from the group consisting of halides, alkoxides and oxides of niobium (Nb).

delete

A process for producing acrolein, which comprises preparing glycerol by dehydration in the presence of an amorphous niobium solid acid catalyst prepared by the process of any one of claims 5 to 6.

9. The method of claim 8,
Wherein the dehydration reaction proceeds in a gas phase reaction at 250 to 350 占 폚.