KR102164613B1 - Catalyst for dehydration of glycerin, preparing method thereof and production method of acrolein using the catalyst - Google Patents

Abstract

The present invention relates to a catalyst for a glycerin dehydration reaction, a method for producing the same, and a method for producing acrolein using the catalyst. The catalyst according to an embodiment of the present invention is used in the glycerin dehydration reaction and exhibits high catalytic activity, high yield, and high acrolein selectivity, and has a property that carbon is not easily deposited, and thus has a longer life than the conventional catalyst.

Description

A catalyst for glycerin dehydration reaction, a method for producing the same, and a method for producing acrolein using the catalyst TECHNICAL FIELD

The present invention relates to a catalyst for a glycerin dehydration reaction, a method for producing the same, and a method for producing acrolein using the catalyst.

Acrolein is a simple unsaturated aldehyde compound, has high reactivity including incomplete reactive groups, and is used as a major intermediate for the synthesis of various compounds. In particular, acrolein has been widely used as an intermediate product for the synthesis of acrylic acid, acrylic acid ester, superabsorbent resin, animal feed supplement, or food supplement.

In the past, such acrolein was prepared mainly through atmospheric oxygen and selective gas phase oxidation reactions using propylene synthesized in an petroleum process as a starting material. However, as environmental problems such as the reduction of fossil fuels and the greenhouse effect gradually emerged, many studies on the method of synthesizing acrolein using renewable raw materials that are not based on fossil fuels have been conducted.

Accordingly, as a natural product, glycerin, which can be obtained as a by-product of the process of synthesizing biodiesel, has attracted much attention as a raw material for manufacturing acrolein. In particular, the market size of glycerin is increasing according to the production amount of biodiesel, and a method that can be applied industrially is being studied due to the decrease in the price of glycerin.

As an example, a method of obtaining a mixture of acrolein and acrylic acid by dehydrating glycerin in the presence of a catalyst is known. The dehydration reaction of glycerin proceeds as a gas phase oxidation reaction in the presence of a catalyst, and the use of a catalyst is essential. In particular, from the glycerin dehydration reaction, acrolein is often produced in a catalyst having a strong acid strength, and in particular, it is known that the production efficiency of acrolein is higher as the amount of the B?sted acid point is greater than the Lewis acid point. Typical acid catalysts with strong Bronsted acid sites include zeolites, heteropoly acids, sulfates, phosphates and metal oxides, and are known to exhibit high catalytic activity in glycerol dehydration.

However, in the case of these catalysts, there is a problem that the generation of by-products increases due to coke deposition, and in order to increase the acrolein yield, efforts to develop catalysts that can significantly reduce the generation of by-products by suppressing the deposition of carbon are continued. have.

The present invention provides a catalyst for a glycerin dehydration reaction and a method for producing the same, which has an increased life by suppressing the deposition of carbon during the dehydration reaction of glycerin, and exhibits high selectivity and efficiency for acrolein.

In addition, the present invention provides a method for producing acrolein using the catalyst.

According to an embodiment of the present invention, there is provided a catalyst for a glycerin dehydration reaction of the following formula (1) in which the metal oxide of M ¹ coats at least a part of a zirconium-containing composite oxide.

[Formula 1]

M ¹ /Zr _a M ² _b W _c P _d H _x O _y

In Formula 1,

M ¹ is a metal oxide containing Fe, V, Mo, or a combination thereof,

M ² is Ni, Zn, Ce, V, Mo, Co, or a combination thereof,

a, b, c, d, and e represent the composition ratio of each atom, a is 0.1 to 6, b/a is 0 to 1, c/a is 0 to 1, and d/a is 0 to Is 10,

x and y are values determined according to the bonding state of the crystal water and are 0 to 10,

"/" indicates that the metal oxide of M ¹ coats at least part of the complex oxide of Zr _a M ² _b W _c P _d H _x O _y ,

M ¹ is included in an amount of 1 to 10 parts by weight based on the weight of Zr _a M ² _b W _c P _d H _x O _y .

For example, a may be 0.5 to 1, b may be 0.01 to 0.3, c may be 0.01 to 0.3, and d may be 1 to 5.

Specifically, the catalyst of the formula (1) is _{2.3wt% Fe / ZrZn 0.02 W 0.1} H x (PO 4) 2, or _{3.5wt% Fe / ZrZn 0 .02 W} 0. 1 H x (PO 4) 2 and , The x may be 2 to 6.

Meanwhile, according to another embodiment of the invention, after mixing an aqueous solution of at least one precursor selected from the group consisting of a precursor of Ni, Zn, Ce, V, Mo, or Co, a zirconium precursor, a phosphorus precursor, and a tungsten precursor, Drying and firing to produce a catalyst precursor; And coating the catalyst precursor with a metal oxide including Fe, V, Mo, or a combination thereof in an amount of 1 to 10 parts by weight based on the weight of the catalyst precursor by impregnation method, drying and firing; including There is provided a method for preparing a catalyst for a glycerin dehydration reaction.

The firing process after the metal oxide coating may be performed at a temperature of 500 to 700° C. for 2 to 7 hours.

On the other hand, according to another embodiment of the present invention, under the glycerin dehydration catalyst, there is provided a method for producing acrolein comprising the step of dehydrating glycerin.

The catalyst according to an embodiment of the present invention is used in the glycerin dehydration reaction and exhibits high catalytic activity, high yield, and high selectivity for acrolein, and has a property that carbon is not easily deposited, and thus has a longer life than the conventional catalyst. .

1 is a schematic diagram of an experimental reaction apparatus according to an embodiment of the present invention.
2 is a schematic diagram of an experimental reaction apparatus according to another embodiment of the present invention.

In the present invention, terms such as first and second are used to describe various components, and the terms are used only for the purpose of distinguishing one component from other components.

In addition, terms used in the present specification are only used to describe exemplary embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present specification, terms such as "comprise", "include" or "have" are intended to designate the presence of implemented features, numbers, steps, components, or a combination thereof, and one or more other features or It is to be understood that the possibility of the presence or addition of numbers, steps, elements, or combinations thereof is not preliminarily excluded.

The present invention will be described in detail below and exemplify specific embodiments, as various changes can be made and various forms can be obtained. However, this is not intended to limit the present invention to a specific form disclosed, it should be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the present invention.

Hereinafter, a catalyst for a glycerin dehydration reaction according to a preferred embodiment of the present invention, a method for preparing the same, and a method for preparing acrolein using the catalyst will be described in more detail.

According to one embodiment of the present invention, there is provided a catalyst for a glycerin dehydration reaction of the following formula (1) in which the metal oxide of M ¹ coats at least a part of a zirconium-containing composite oxide.

[Formula 1]

M ¹ /Zr _a M ² _b W _c P _d H _x O _y

In Formula 1,

M ¹ is a metal oxide containing Fe, V, Mo, or a combination thereof,

M ² is Ni, Zn, Ce, V, Mo, Co, or a combination thereof,

a, b, c, d, and e represent the composition ratio of each atom, a is 0.1 to 6, b/a is 0 to 1, c/a is 0 to 1, and d/a is 0 to Is 10,

x and y are values determined according to the bonding state of the crystal water and are 0 to 10,

"/" indicates that the metal oxide of M ¹ coats at least part of the complex oxide of Zr _a M ² _b W _c P _d H _x O _y ,

M ¹ is included in an amount of 1 to 10 parts by weight based on the weight of Zr _a M ² _b W _c P _d H _x O _y .

First, in the present invention, the term "metal oxide" means that when coco on the catalyst is deposited, oxygen and coke react to generate CO and CO ₂ gas to help regenerate the catalyst and do not interfere with the active point of the catalyst, so that the activity is maintained for a long time. Refers to the metal. Accordingly, when the metal oxide is used in the present invention, coke on the catalyst reacts with oxygen to prevent coke deposition of the catalyst.

As described above, in the dehydration reaction of glycerin according to the conventional method, carbon is deposited on the catalyst as the reaction proceeds, resulting in a problem of deactivating the catalyst and shortening the catalyst life. In particular, among the known acid catalysts, the acid catalyst having a large Bronsted acid point has good production efficiency of acrolein, but it is difficult to carry out the dehydration reaction for a long time because carbon is deposited on the acid catalyst during the dehydration reaction and is easily deactivated.

In particular, in order to prepare acrolein and acrylic acid from glycerin, conventional catalysts form by-products such as hydroxypropanone, propanaldehyde, acetaldehyde, acetone, polycondensation products of glycerin, and cyclic glycerin ether. These impurities produced greatly reduce the field of application of acrolein produced by the dehydration of glycerin. In addition, phenol and polyaromatic compounds are produced to form coke on the catalyst, causing deactivation. Deactivation of the catalyst makes it impossible to continuously operate the glycerin dehydration reaction, which makes commercialization difficult.

In addition, one of the biggest causes of this decrease in catalytic activity is the loss of the catalytic activity point due to deposition of coke carbon generated during the reaction. In particular, as factors affecting the formation of coke carbon in the glycerin dehydration reaction, reaction conditions such as reaction temperature, space velocity, partial pressure of oxygen and water vapor in the reactant, material transfer in the catalyst by the catalyst pore structure, the amount and acid point of the acid point on the catalyst surface Such as this century. The acid point of the catalyst is generally an active point that promotes the dehydration reaction, but when there is an excessive amount of strong acid point on the surface of the catalyst, the coke carbon precursor is excessively generated due to the intermolecular condensation due to side reactions, which causes the dehydration of the catalyst. Results.

Accordingly, in the present invention, in order to solve such a conventional problem, a specific catalyst composition is applied to suppress the generation of coke carbon during the reaction, and thus the life of the catalyst can be effectively extended. In particular, by using a catalyst capable of increasing the selectivity of acrolein, it is possible to obtain acrolein and/or acrylic acid from glycerin in high yield. By using a catalyst capable of removing the coke carbon generated therefrom, the glycerin dehydration reaction process using a conventionally commercially used fixed bed reactor can be continuously operated to remarkably improve the overall process efficiency.

In particular, the present invention relates to the development of a catalyst for producing acrolein by dehydrating glycerin. In detail, Zr, P, W and transition metals are added to the composite component Zr Phosphate catalyst system with oxide metals such as Fe, Mo, V, etc. coated with an enhancer, thereby oxidizing coke carbon to inhibit the deposition of coke carbon on the catalyst and to generate by-products. It is characterized in that to provide a catalyst showing a high acrolein yield for a long time by minimizing this.

For example, in order to further improve the acrolein yield and catalyst efficiency than the conventional zirconium phosphate, the catalyst of Formula 1 is a is 0.5 to 1, b is 0.01 to 0.3, c is 0.01 to 0.3, d is 1 to 5 Can be

In particular, Zr, P, W and a transition metal composite component Zr Phosphate catalyst system, that is, Zr _a M ² _b W _c P _d H _x O _y based on the weight of the metal oxide such as Fe, Mo, V is 1 It may be included in to 10 parts by weight, preferably 1.2 to 5 parts by weight, more preferably 1.5 to 4.5 parts by weight. The content of the metal oxide should be 1 part by weight or more in terms of the effect of removing coke, and when excessively supported, the content of the metal oxide should be 10 parts by weight or less in this respect because there is a problem of component loss in the use of the catalyst.

More particularly, the catalyst of the formula (1) is _{2.3wt% Fe / ZrZn 0.02 W 0.1} H x (PO 4) 2, or _{3.5wt% Fe / ZrZn 0 .02 W} 0. 1 H x (PO 4) 2 And, x may be 2 to 6.

The catalyst for glycerin dehydration of the present invention may further include a carrier on which the composite metal oxide is fixed.

Meanwhile, according to another embodiment of the present invention, a method of preparing a catalyst represented by Formula 1 described above using a precipitation method is provided. Specifically, the method for preparing the catalyst represented by Formula 1 is a mixture of an aqueous solution of at least one precursor selected from the group consisting of Ni, Zn, Ce, V, Mo, or Co precursors, a zirconium precursor, a phosphorus precursor, and a tungsten precursor. After the drying and firing process to produce a catalyst precursor; And coating the catalyst precursor with a metal oxide including Fe, V, Mo, or a combination thereof in an amount of 1 to 10 parts by weight based on the weight of the catalyst precursor by impregnation method, drying and firing; including do.

The catalyst of Formula 1 is not particularly limited in a method of mixing an aqueous solution of a precursor of M ² atoms, such as Ni, Zn, Ce, V, Mo, or Co, a zirconium precursor, a phosphorus precursor, and a tungsten precursor. As a non-limiting example, the precursors may be sequentially introduced into the reactor one by one and mixed, or may be introduced and mixed at a time. Among them, when a zirconium precursor is added to the reactor, a precursor of M ² atom, and a tungsten precursor are added thereto, and then a phosphorus precursor compound is added, a phosphorus precursor after the zirconium precursor, the precursor of M ² atom, and the tungsten precursor are completely dissolved. Since the compound is added, the precursors are easily dissolved and crystals having a stable structure can be more easily formed, thereby improving the catalyst yield.

In the step of mixing the precursor compounds of each component in the catalyst, before introducing the precursor into the reactor, the precursors are introduced while stirring the solvent, or some precursors are added to the reactor and other precursors are added while stirring some precursors. Alternatively, all precursors may be added to the reactor and the mixture of precursors may be stirred to increase the amount of catalyst produced. For example, before introducing the precursor into the reactor, a solvent such as water may be added and the precursor may be sequentially or simultaneously introduced while stirring a solvent such as water. In addition, as another example, some of the precursors may be first introduced into the reactor, and the remaining precursors may be sequentially or simultaneously introduced while stirring. As another example, precursors may be sequentially or simultaneously introduced into a reactor to form a mixture, and the mixture may be stirred.

In all of the above cases, the mixture of precursors may be continuously stirred even after all the precursors have been added to the reactor. In particular, the stirring of the mixture may be performed under a temperature of about 25 to 200° C. to facilitate bonding between metals.

In addition, the agitation may be performed for a sufficient time so that all the introduced precursors are well mixed so that a large amount of precipitation occurs. For example, the agitation may be performed for about 3 to 48 hours.

A process of precipitating the precursor compound of the catalyst represented by Chemical Formula 1 from an aqueous solution obtained by mixing the precursor compounds of each component may be further included.

The precursors of each component used in the above manufacturing method may utilize all of various precursors known in the art to which the present invention pertains. As a non-limiting example, zirconyl chloride, zirconyl bromide, zirconyl iodide and zirconyl nitrate may be used as the zirconium precursor. Further, as the precursor of the M ² atom, an oxide, hydroxide, nitrate, oxalate, phosphate, or halide of the M ² metal may be used. For example, Ni(NO ₃ ) ₂ ㆍ6H ₂ O may be used as a nickel precursor, Zn(NO ₃ ) ₂ may be used as a zinc precursor, and Ce(NO ₃ ) ₂ etc. may be used as a cerium precursor. Can be used, and NH ₄ VO ₃ etc. can be used as a vanadium precursor, (NH ₄ ) ₆ MoO ₂₄ ㆍ4 ₂ O can be used as a molybdenum precursor, and Co(NO ₃ ) ₂ as a cobalt precursor ㆍ6H ₂ O etc. can be used. In addition, as the precursor of the M ² atom, one or two or more precursors may be used, and a zinc precursor and a vanadium precursor may be used together as a non-limiting example. In addition, as the phosphorus precursor compound, phosphoric acid and a phosphate in which one or more protons of phosphoric acid are substituted with cations of Group 1, 2, or 13 or ammonium cations may be used. As the tungsten precursor, ammonium metatungstate, ammonium paratungstate, tungstic acid, tungsten blue oxide and tungsten trioxide may be used. The precursors may be anhydrous or hydrate. In addition, the precursors may be used in an appropriate amount according to the ratio of the atoms and atomic groups of Formula 1.

In the step of mixing the precursors, a suitable solvent may be used for uniform mixing of the precursors. The solvent is not particularly limited, and non-limiting examples include water.

The precursor compound of the catalyst represented by Chemical Formula 1 may be precipitated from the mixed aqueous solution of the precursors, and filtering the precipitated catalyst precursor compound and washing with water, alcohol, or a mixture thereof may be further included. In particular, when the precipitate of a metal compound is washed with alcohol, a catalyst having a larger surface area can be prepared. The catalyst having such a large surface area may exhibit better catalytic activity and selectivity of acrolein in the glycerin dehydration reaction.

Examples of alcohols that may be used in the washing step include alkyl alcohols having 1 to 10 carbon atoms such as methanol, ethanol, propanol, butanol, pentanol, and hexanol.

In addition, after mixing the aqueous solution of the precursor, a drying and sintering process may be performed to produce the precursor compound of the catalyst represented by Formula 1. Here, in the step of generating the catalyst precursor compound, the drying process may be performed at a temperature of 25 to 200 °C, and may be performed for 3 to 48 hours. In addition, the sintering process in the step of generating the catalyst precursor compound may be performed at a temperature of 350 to 650° C., and may be performed for 3 to 48 hours.

After preparing a catalyst precursor compound containing a transition metal such as Zr, P, W, etc. by this method, a metal oxide containing Fe, V, Mo, or a combination thereof is added to the catalyst precursor by impregnation with the catalyst precursor. The catalyst of Formula 1 may be prepared by coating in an amount of 1 to 10 parts by weight based on the weight of the precursor, drying and firing.

As the precursor of the metal oxide component used in the impregnation method, all of a variety of precursors known in the art may be used. As a non-limiting example, an oxide, hydroxide, nitrate, oxalate, phosphate, or halide of the M ¹ metal may be used as the precursor of the M ¹ atom that becomes the metal oxide component. For example, Fe(NO ₃ ) ₃ etc. may be used as an iron precursor, NH ₄ VO ₃ etc. may be used as a vanadium precursor, and (NH ₄ ) ₆ MoO ₂₄ ㆍ4 ₂ O, etc. may be used as a molybdenum precursor. Can be used. In addition, as the precursor of the M ¹ atom, one or two or more precursors may be used, and as a non-limiting example, an iron precursor and a vanadium precursor may be used together. The precursors may be anhydrous or hydrate. In addition, the precursors may be used in an appropriate amount according to the ratio of the atoms and atomic groups of Formula 1.

In particular, the precursor compound of the metal oxide component is a composite component Zr Phosphate catalyst system in which Zr, P, W and a transition metal are added, that is, 1 to 10 parts by weight, preferably, based on the weight of the precursor compound of the catalyst of Formula 1 1.2 to 5 parts by weight, more preferably 1.5 to 4.5 parts by weight may be included.

It may further include the step of filtering the catalyst precursor compound coated with the metal oxide and washing with water, alcohol, or a mixture thereof. Alcohol that can be used in the washing step may be an alkyl alcohol having 1 to 10 carbon atoms such as methanol, ethanol, propanol, butanol, pentanol, and hexanol.

After performing the impregnation method of coating the metal oxide, a drying and firing process may be performed to produce the catalyst represented by Chemical Formula 1. Here, the drying process after the metal oxide coating may be performed at a temperature of 25 to 200° C., and may be performed for 3 to 48 hours. In addition, the firing process after the metal oxide coating may be performed at a temperature of 500 to 700° C., and may be performed for 2 to 7 hours.

In the present invention, after passing through the dry firing process, the step of molding and assembling the fired material may be further included.

In addition to the above-described steps, the method for preparing the catalyst may further include steps commonly employed in the technical field to which the present invention pertains.

Meanwhile, according to another embodiment of the present invention, a method for producing acrolein comprising the step of dehydrating glycerin under the catalyst for dehydration of glycerin is provided.

The manufacturing method of the acrolein, for example, may provide acrolein by dehydrating glycerin under a continuous flow gas phase reaction system in which the catalyst is present.

As a reactant in the above preparation method, glycerin or an aqueous glycerin solution may be used. In addition, an inert gas or a mixed gas of air or oxygen may be used as the carrier gas of the reactant. In particular, the dehydration reaction may be carried out under conditions of a glycerin concentration of 25 to 75% (mol%). In this case, glycerin may be included in an amount of 1 to 10% (mol%) of the gaseous reactant, and oxygen may be included in an amount of 1 to 20% (mol%).

In addition, the amount of the catalyst used in Formula 1 as described above in the method for producing acrolein may be appropriately adjusted according to the amount and concentration of glycerin as a reactant, for example, 10 to 300 glycerin mmol/h·g _cat It can be filled at a weight space velocity, preferably 10 to 100 glycerin mmol/h·g _cat , more preferably 5 to 50 glycerin mmol/h·g _cat . If the amount of the catalyst is too small, the yield of the final acrylic acid may decrease due to a decrease in the glycerin conversion rate, and if the amount of the catalyst is too large, the generation of impurities may be promoted due to an excessive increase in the contact time, resulting in a decrease in the yield of acrylic acid.

In the present invention, the glycerin reaction process may be performed at a gas space velocity (GHSV) of 500 to 5000 h ^-1 .

In addition, the step of reacting glycerin may be performed at a temperature of 250 to 350 °C. The step of reacting glycerin is an endothermic reaction, and in order to increase the yield of final acrylic acid by producing acrolein with high conversion and selectivity, it is preferable to perform the reaction at a temperature within the above range. If the reaction temperature is too low, the conversion rate of glycerin may decrease, and if the reaction temperature is too high, the selectivity of acrolein may decrease due to excessive side reactions.

In addition, after performing the dehydration reaction, a partial oxidation reaction of acrolein from the product obtained from the dehydration reaction is performed, and a step of finally converting acrolein produced through the dehydration reaction of glycerin to acrylic acid may be further performed.

The method for producing acrolein according to the present invention may maintain a glycerin conversion of 90% or more, measured at a point where 300 hours or more elapses after the initiation of the reaction, and a selectivity to acrolein may be 35% or more.

In addition to the above-described steps, the method of manufacturing the acrolein may further include a step commonly employed in the technical field to which the present invention pertains.

Hereinafter, a preferred embodiment of the present invention will be described in detail. However, these examples are for illustrative purposes only, and it will not be construed that the scope of the present invention is limited by these examples.

<Example>

Preparation Example 1: Preparation of a catalyst for glycerin dehydration reaction

_{ZrZn 0 .02 V 0.1 W 0. 1} H x (PO 4) 2 catalyst to 1 mole ratio of Zr, V and Zn molar ratio of the transition metal is from 0.02 and 0.1, respectively, in a molar ratio of P 2, It was prepared by adjusting the molar ratio of W to 0.1. To this end, 183.11 g of zirconium oxychloride, 3.414 g of zinc precursor (Zn(NO ₃ ) 6H ₂ O), 6.464 g of vanadium precursor (ammonium vanadate), 13.93 g of tungsten precursor (ammonium metatungstate hydrate) were mixed in 2250 ml of distilled water. After that, 132.05g of a precursor (ammonium phosphate: NH ₄ H ₂ PO ₄ ) was added.

Then, when a precipitate was formed after mixing, the mixture was heated to 90° C. and stirred for at least 3 days, and the precipitate was separated by filtration and washed with ethanol 3 to 5 times. The cake-shaped precipitate obtained after washing was dried in an oven at 100° C. for 12 hours. The dried cake was calcined at 700° C. for 6 hr in an air atmosphere to prepare a composite metal oxide.

For 20 g of the composite metal oxide, Fe(NO ₃ ) ₃ ㆍ9H ₂ O was dissolved in distilled water using 3.328 g (2.3 wt%) as an enhancer, and then impregnated to prepare a catalyst precursor coated with metal oxide. I did. The catalyst precursor compound thus prepared was dried in an oven at 100° C. for about a day, and then molded into a cylindrical shape of 5 mm in length and fired at 700° C. for 6 hours to obtain 2.3 wt% Fe/ZrZn _0.02 W _0.1 H _x (PO ₄ ) ₂ . The catalyst was prepared.

Preparation Example 2: Preparation of a catalyst for glycerin dehydration reaction

In the same manner as in Preparation Example 1, except that Fe (NO ₃ ) ₃ ㆍ9H ₂ O was used in an amount of 5.064 g (3.5 wt%) as a metal oxide component in Preparation Example 1, 3.5 wt% of a catalyst for glycerin dehydration reaction Fe/ZrZn _0.02 W _0.1 H _x (PO ₄ ) ₂ was obtained.

Comparative Preparation Example 1: Preparation of catalyst for glycerin dehydration reaction

ZrP was obtained as a catalyst for glycerin dehydration reaction by a precipitation method.

Comparative Production Example 2: Preparation of catalyst for glycerin dehydration reaction

BPO ₄ was obtained as a catalyst for glycerin dehydration reaction by a precipitation method.

Comparative Preparation Example 3: Preparation of catalyst for glycerin dehydration reaction

H ₃ PW ₁₂ O ₄₀ was obtained as a catalyst for glycerin dehydration reaction by a precipitation method.

Comparative Production Example 4: Preparation of catalyst for glycerin dehydration reaction

In Preparation Example 1, a catalyst for glycerin dehydration reaction ZrZn _0.02 W _0.1 H _x (PO ₄ ) ₂ was obtained in the same manner as in Preparation Example 1, except that the process of coating the metal oxide component by the impregnation method was not performed.

Comparative Production Example 5: Preparation of catalyst for glycerin dehydration reaction

11.08 wt% BPO ₄ /SiO ₂ was obtained as a catalyst for glycerin dehydration reaction by the impregnation method.

Examples 1 to 2 and Comparative Examples 1 to 4: Dehydration reaction of glycerin

Using the reaction apparatus as shown in FIG. 1, the glycerin dehydration reaction was performed using the catalysts prepared according to Preparation Examples 1 to 2 and Comparative Preparation Examples 1 to 4.

A glass reactor (outer diameter 9 mm, length 25 cm) was used, a certain amount of catalyst was filled, and liquid reactant Glycerin (28.08 wt%) was injected at a constant rate, and the reactant was vaporized and supplied to the reactor at a constant rate with Air. The experiment was performed under conditions of GHSV: 10000 h ^-1 or more. The sampling operation was performed in a cooler for the condensation process, and a certain amount of distilled water was added to the sample bottle to condense the reactants. Gas Chromatography was used to analyze the reaction product, and the analysis was performed using a flame ionization detector (FID). In addition, in this experiment, the gas phase reactant (CO _x ) was not analyzed, and the catalyst performance was evaluated by analyzing only the liquid reactant.

The analysis results of the liquid product after the glycerin dehydration reaction of Examples 1 to 2 and Comparative Examples 1 to 4 in which the glycerin reaction and analysis were evaluated are as shown in Table 1 below.

catalyst glycerin
Conversion rate
(%) Acrolein
Liquid selectivity
(%) Comparative Selectivity 1
(%) Comparative Selectivity 2
(%) Comparative Example 1 ZrP 50.80 54.00 0.19 0.66 Comparative Example 2 BPO ₄ 56.16 75.05 0.11 0.23 Comparative Example 3 H ₃ PW ₁₂ O ₄₀ 7.36 33.37 0.21 1.79 Comparative Example 4 ZrZn _0.02 W _0.1 H _x (PO ₄ ) ₂ 39.47 65.36 0.16 0.62 Example 1 2.3wt%Fe/ZrZn _0.02 W _0.1 H _x (PO ₄ ) ₂ 100 72.49 0.06 0.32 Example 2 3.5wt%Fe/ZrZn _0.02 W _0.1 H _x (PO ₄ ) ₂ 100 72.31 0.07 0.31 Comparative selectivity 1 = (hydroxyacetone selectivity + acetic acid selectivity) / acrolein selectivity
Comparative selectivity 2 = (propion aldehyde selectivity + propionic acid selectivity + aromatic substance selectivity) / acrolein selectivity

Example 3 and Comparative Example 5: Dehydration reaction of glycerin

Using the reaction apparatus as shown in Fig. 2, the glycerin dehydration reaction was performed using the catalysts prepared according to Preparation Example 2 and Comparative Preparation Example 5.

A stainless-steel reactor (outer diameter 9.5 mm, length 30 cm) was used, a certain amount of catalyst was charged, and then liquid reactant, glycerin (28.08 wt%) was injected at a constant rate and sent to the evaporator heater, and the vaporized reactant was By supplying to the reactor with Air or N ₂ at a constant rate, the experiment was performed under the conditions of GHSV: 10000 h ^-1 or more. Analysis methods were largely divided into liquid product analysis and gaseous product analysis, and analyzed by GC. As for the liquid product, the condensed liquid product was analyzed by a GC-FID detector, and the gaseous product was analyzed by a GC-TCD detector. The reason for the gas phase analysis with the liquid was analyzed to calculate the conversion of C components reacted with Air to CO and CO ₂ . On the other hand, in the case of the catalyst analyzing only the liquid product, the generated CO _x must be reflected, and the CO _x value varies depending on the operating conditions and time, and is in the range of approximately 0 to 20% as shown in Example 3 and Comparative Example 5 below. Is in.

The glycerin dehydration catalysts of Example 3 and Comparative Example 5, in which the glycerin reaction and analysis were evaluated, and the time and glycerin conversion rate after the dehydration reaction are shown in Table 2 below.

catalyst Time
(hr) glycerin
Conversion rate
(%) Comparative Example 5 11.08wt% BPO ₄ /SiO ₂ 1/5/24 3.3/0.9/0.8 Example 3 3.5wt%Fe/ZrZn _0.02 W _0.1 H _x (PO ₄ ) ₂ 1/5/26 56.3/100/100

In addition, additional analysis results of the liquid product after the glycerin dehydration reaction of Example 3 and Comparative Example 5 are shown in Table 3 below.

Acrolein
Liquid selectivity
(%) Comparative Selectivity 1
(%) Comparative Selectivity 2
(%) Comparative Example 5 54.4/13.3/12.5 0.42/1.27/0.41 0.41/5.24/6.65 Example 3 75.3/81.1/75.6 0.03/0.05/0.06 0.30/0.18/0.26 Comparative selectivity 1 = (hydroxyacetone selectivity + acetic acid selectivity) / acrolein selectivity
Comparative selectivity 2 = (propion aldehyde selectivity + propionic acid selectivity + aromatic substance selectivity) / acrolein selectivity

Additional analysis results of the liquid phase and gas phase (CO _x ) reaction products after the glycerin dehydration reaction of Example 3 and Comparative Example 5 are as shown in Table 4 below.

Acrolein
Selectivity
(%) Acrolein
yield
(%) Comparative Selectivity 1
(%) Comparative Selectivity 2
(%) Cox
(%) Comparative Example 5 54.4/13.3/12.4 1.82/0.12/0.10 0.42/1.27/0.41 0.41/5.24/6.65 0/0.3/0.3 Example 3 75.3/69.0/60.0 42.4/69.0/60.0 0.03/0.05/0.07 0.30/0.40/0.60 0/14.6/20.2 Comparative selectivity 1 = (hydroxyacetone selectivity + acetic acid selectivity) / acrolein selectivity
Comparative selectivity 2 = (propion aldehyde selectivity + propionic acid selectivity + aromatic substance selectivity) / acrolein selectivity

As shown in Tables 1 to 4, in the case of Examples 1 to 3 in which the glycerin dehydration reaction was performed using the catalyst according to the present invention, the glycerin dehydration reaction process using a fixed bed reactor that has been commercially used was continuously operated. It can be seen that, from glycerin, acrolein and/or acrylic acid can be obtained in high yield.

In particular, as described in Table 4, in the present invention, when a metal oxide such as Fe is used through the value of CO _x , coke deposited on the catalyst undergoes an oxidation reaction, resulting in CO. A gas such as CO ₂ is generated, which can be judged as a result of a decrease in coke deposition on the catalyst during the reaction. Therefore, it was confirmed that there is a property that can maintain the catalytic activity for a long period of time and obtain high activity by reducing the amount of coke deposited in the catalyst through the value converted to CO _x .

Claims (7)

A catalyst for glycerin dehydration reaction of the following formula (1), wherein the metal oxide of M ¹ coats at least a part of the zirconium-containing complex oxide:
[Formula 1]
M ¹ /Zr _a M ² _b W _c P _d H _x O _y
In Formula 1,
M ¹ is Fe,
M ² is Zn,
a, b, c, and d represent the composition ratio of each atom, a is 0.5 to 1, b is 0.01 to 0.3, c is 0.01 to 0.3, d is 1 to 5, and b/a is 0.01 To 0.6, c/a is 0.01 to 0.6, d/a is 1 to 10,
x and y are values determined according to the bonding state of the crystal water, x is 2 to 6, y is 8,
"/" indicates that the metal oxide of M ¹ coats at least part of the complex oxide of Zr _a M ² _b W _c P _d H _x O _y ,
M ¹ is included in an amount of 1.5 to 4.5 parts by weight based on the weight of Zr _a M ² _b W _c P _d H _x O _y .
delete The method of claim 1,
The catalyst is 2.3wt% Fe/ZrZn _0.02 W _0.1 H _x (PO ₄ ) ₂ , or 3.5wt% Fe/ZrZn _0.02 W _0.1 H _x (PO ₄ ) ₂ ,
Catalyst for glycerin dehydration reaction.
Mixing an aqueous solution of a zinc precursor, a zirconium precursor, a phosphorus precursor, and a tungsten precursor, followed by drying and firing to produce a catalyst precursor; And
Coating the catalyst precursor with a metal oxide containing Fe by an impregnation method in an amount of 1.5 to 4.5 parts by weight based on the weight of the catalyst precursor, and drying and firing;
A method for producing a catalyst for a glycerin dehydration reaction according to claim 1 comprising a.
The method of claim 4,
The method for producing a catalyst for dehydration of glycerin is carried out at a temperature of 500 to 700° C. after the metal oxide coating is performed.
The method of claim 4,
The method for producing a catalyst for dehydration of glycerin is performed for 2 to 7 hours after the metal oxide coating is performed.
A method for producing acrolein comprising the step of dehydrating glycerin under the catalyst for glycerin dehydration of claim 1.

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