KR20110116480A - The noble metal based catalyst supported on hydrotalcite-like support and the method for the producing of 1,2-propanediol - Google Patents

Abstract

The present invention relates to a noble metal catalyst in which a Group VIIIB precious metal element on a standard periodic table is supported on a pseudohydrotalcite carrier, a method for preparing the noble metal catalyst, and dehydration and hydrogenation of glycerol using the noble metal catalyst. -A method of selectively preparing propanediol.
The noble metal catalyst of the present invention is applied to the dehydration and hydrogenation of glycerol to maintain high conversion of glycerol and selectivity and yield of 1,2-propanediol. Useful as a process catalyst for the conversion to 2-propanediol.

Description

Noble metal based catalyst supported on hydrotalcite-like support and the method for the producing of 1,2-propanediol}

The present invention selectively prepares 1,2-propanediol from glycerol using a noble metal catalyst having a Group VIIIB precious metal element on a standard periodic table, a method for preparing the noble metal catalyst, and the noble metal catalyst on a pseudohydrotalcite carrier. It is about how to.

1,2-propanediol is a transparent, viscous, weakly acidic liquid with a pale yellow color with a molecular weight of 76, a freezing point of -59 ° C and a boiling point of 188 ° C, and is well mixed with water. 1,2-propanediol is widely used as a raw material for various chemical products such as antifreeze, surfactant, synthetic resin, and the like as an intermediate for compound synthesis.

As a general method for synthesizing 1,2-propanediol, there is a method for producing glycerol by dehydration and hydrogenation under a specific catalyst. Method for preparing 1,2-propanediol from glycerol is to use sulfuric acid as a homogeneous catalyst, a method of mixing the alkali metal oxide with a cation exchange resin such as Amberlyst ^® 70, the active material is a transition metal such as copper Using a catalyst prepared by impregnating one or two selected metal oxides at an appropriate ratio, using a catalyst prepared at high temperature and high pressure, and a catalyst prepared by impregnating a precious metal with one or two selected metal oxides at an appropriate ratio. It can be divided into the methods used.

The method for producing 1,2-propanediol by dehydration and hydrogenation of glycerol known to date is as follows.

US Patent Publication No. 2009-021650 discloses a method for preparing 1,2-propanediol by performing dehydration and hydrogenation of glycerol under a catalyst prepared by mixing oxides such as zinc and zirconyl with copper oxide in a constant ratio. It is. The reaction is carried out for 10 hours using an oxide having a composition ratio of copper: zinc: aluminum = 4: 4: 2 at 215 ° C. temperature and 50 bar pressure conditions. As a result, glycerol was converted almost 100%, 1,2-propanediol selectivity is about 87%, the yield is reported to be about 85%.

Japanese Patent Application Laid-Open No. 2007-283175 discloses a method for producing 1,2-propanediol by carrying out dehydration and hydrogenation of glycerol under a catalyst prepared by impregnating various alkaline metal oxides with ruthenium. The reaction is carried out in a batch reactor at 180 ° C. temperature and 80 atm conditions for 10 hours. As a result, zirconia impregnated ruthenium has a glycerol conversion of about 70%, 1,2-propanediol selectivity of about 55%, yields of about 38%, and ruthenium on alkaline metal oxide carriers. This impregnated catalyst reported lower conversion of glycerol, selectivity and yield of 1,2-propanediol than ruthenium catalyst impregnated with zirconia.

Japanese Patent Application Laid-Open No. 2008-266234 discloses that the catalysts impregnated with ruthenium in activated carbon are added with twice the amount of cation exchange resins Amberlyst ^® 15 and Amberlyst ^® 70 to perform dehydration and hydrogenation of glycerol. A method for preparing 2-propanediol is disclosed. The reaction is carried out in a batch reactor at 180 ° C. and 80 atm for 10 hours. As a result, the conversion rate of glycerol is 49%, the selectivity of 1,2-propanediol is 71%, and the yield of 1,2-propanediol is reported at 35%.

Korean Patent Publication No. 2004-69565 discloses a method for separating 1,3-propanediol and 1,2-propanediol produced by biological metabolism of glucose, specifically, 1,2- and 1,3- The method for preparing propanediol is not shown in detail, and only the separation method for reduced pressure distillation of glycerol and 1,2-propanediol mixed in a constant ratio is introduced.

In addition, methods for the simultaneous production of 1,2- and 1,3-propanediol using copper / zinc oxide catalysts are known. [Julien Chaminand, Laurent Djakovitch, Pierre Gallezot, Philippe Marion, Catherine Pinel and Cecile Rosier, Green Chem., 6, 359-361, 2004] At this time, the conversion rate of glycerol is as low as 20%, and 1,2-propanediol The selectivity is 95% and the yield of 1,2-propanediol is reported to be around 19%.

In addition, a method of preparing 1,2-propanediol by performing dehydration and hydrogenation of glycerol at 170 ° C. and 50 bar under a catalyst prepared by impregnating ruthenium in different metal oxide carriers is known. Jian Feng, Haiyan Fu, Jinbo Wang, Ruixiang Li, Hua Chen, Xianjun Li, Catal. Comm., 9, 1458-1464, 2008] At this time, the conversion rate of glycerol was about 90% higher, but the selectivity of 1,2-propanediol was lowered to about 20% and the selectivity of the by-product ethylin glycol was 41. It has been reported that the production of ethylene glycol is significantly higher than 1,2-propanediol by%.

Briefly summarized the problems in the conventional manufacturing method described above is as follows. The method using a homogeneous catalyst significantly accelerates the dehydration and hydrogenation of glycerol, resulting in high conversion and selectivity and yield of glycerol and 1,2-propanediol. And, there is a disadvantage that the separation of 1,2-propanediol in the reaction solution after the reaction is not easy. The method of using an ion exchange resin as an additive slightly improves the conversion rate of glycerol and the selectivity of 1,2-propanediol, but when working at a temperature of 120 ° C. or higher, the thermal stability of the ion exchange resin is drastically lowered and thus it is operated for a long time. And it is difficult to reuse the catalyst. The process using a catalyst prepared by impregnating transition metals is carried out in a batch reactor, where the selectivity of 1,2-propanediol is higher than 85%, but the conversion of glycerol is lower than 30%, and thus 1,2- It is economically inefficient because the yield of propanediol is less than about 25%. In the method using a catalyst prepared by impregnating a noble metal, especially ruthenium into a metal oxide, the conversion rate of glycerol is about 70%, which is generally higher than that of the transition metal impregnation catalyst, but the selectivity of 1,2-propanediol is about 30 to 50% Compared to the catalyst, the selectivity of ethylene glycol, which accounts for most of the by-products, is about the same or higher than that of 1,2-propanediol. Ethylene glycol, produced as a by-product in the dehydration and hydrogenation of glycerol, is a light yellow viscous liquid with a boiling point of 198 ° C. Like 1,2-propanediol, it is well mixed with water. Compared with 1,2-propanediol, the boiling point difference is about 10 ℃ and the other chemical properties are similar, so it is not easy to separate the two substances, which makes it difficult to separate 1,2-propanediol with high purity. have. Therefore, in order to obtain high purity 1,2-propanediol, it is necessary to suppress the yield of ethylene glycol produced as a by-product as much as possible.

Glycerol is one of the by-products of biodiesel production and is currently used as a raw material for cosmetics and soap. Recently, the production of biodiesel is soaring, the by-product glycerol is also produced in large quantities compared to demand. Therefore, there is a need for a technique for converting glycerol into other high-value chemicals while securing a stable demand for glycerol released as industrial by-products.

An object of the present invention is to provide a novel noble metal catalyst for synthesizing 1,2-propanediol, in which a Group VIII noble metal element is supported on a pseudo hydrotalcite carrier (A _x B _y Mg _z / Al).

In addition, the present invention provides a method for preparing 1,2-propanediol using a novel noble metal catalyst that suppresses the production of ethylene glycol as a by-product, while maintaining high conversion of glycerol and selectivity of 1,2-propanediol. To provide for other purposes.

In addition, the present invention improves the conversion of glycerol to a pseudo hydrotalcite carrier (A _x B _y Mg _z / Al) prepared by coprecipitation of an aluminum compound, a magnesium compound, a Group IIA metal compound, and a Group IIB metal compound by hydrothermal synthesis. It is another object of the present invention to provide a method for producing a 1,2-propanediol noble metal catalyst, in which a particular noble metal element which is advantageous for the dispersion is uniformly dispersed and supported by an impregnation method.

The present invention is characterized in that the noble metal catalyst for synthesizing 1,2-propanediol is supported on the pseudohydrotalcite carrier represented by the following formula (1), in which one or two noble metal elements selected from Group VIII elements on the standard periodic table are supported. do.

[Formula 1]

A _x B _y Mg _z / Al

In Formula 1, A is a Group IIA metal element selected from calcium, strontium, barium, and radium; B is a Group IIB metal element selected from zinc, cadmium, and mercury; x, y, and z are molar ratios of aluminum (Al) of each metal element as 0 <x≤1, 0 <y≤1, 2≤z≤4, except that x and y are 0 at the same time. do.

In addition, the present invention is characterized by a method for producing a noble metal catalyst for 1,2-propanediol synthesis comprising the following manufacturing process.

Iii) hydrothermally synthesizing an aluminum compound, a magnesium compound, a Group IIA metal compound, and a Group IIB metal compound at 120 ° C to 230 ° C for 1 to 10 hours to produce a hydrotalcite precursor;

Ii) drying and calcining the hydrotalcite precursor to prepare a pseudo hydrotalcite carrier having the composition of Formula 1; And

Iii) a process of preparing a noble metal catalyst by impregnating a VIIB group noble metal compound on a standard periodic table on the pseudohydrotalcite carrier.

In addition, the present invention is characterized by the production method of 1,2-propanediol to perform the dehydration and hydrogenation reaction of glycerol at 120 ℃ to 230 ℃ temperature and 10 to 800 bar pressure conditions under the above noble metal catalyst .

In the present invention, by using a pseudo hydrotalcite carrier represented by the above formula (1) as a carrier supporting a noble metal, the effect of improving the selectivity of 1,2-propanediol and greatly reducing the selectivity of ethylene glycol as a byproduct is obtained.

Further, in the present invention, an effect of improving the conversion rate of glycerol is obtained by selecting and using a Group VIII precious metal element as the catalytic active component.

In the present invention, the novel noble metal catalyst is used for the dehydration and hydrogenation of glycerol, the conversion rate of glycerol 51.5% or more, the selectivity of 1,2-propanediol 75.1% or more, the yield of 1,2-propanediol 41.8 Gain the effect of improving by more than%.

 In the present invention, a novel noble metal catalyst is used for the dehydration reaction and hydrogenation of glycerol, thereby greatly reducing the selectivity of ethylene glycol produced as a by-product to 14.9% or less, thereby obtaining the effect of simplifying the purification process.

In addition, a catalyst prepared by supporting ruthenium (Ru) active metal on a pseudohydrotalcite carrier simultaneously containing aluminum (Al), magnesium (Mg), Group IIA metal, and Group IIB metal among the novel noble metal catalysts according to the present invention. The effect of greatly improving the selectivity of 1,2-propanediol to 83.6% or more and ethylene glycol to 7.3% or less is obtained.

The present invention relates to a novel noble metal catalyst, which makes it possible to selectively produce 1,2-propanediol by dehydration and hydrogenation of glycerol. The precious metal catalyst of the present invention is prepared by impregnating a Group VIIIB precious metal element into a pseudo hydrotalcite carrier (A _x B _y Mg _z / Al) prepared by coprecipitation and hydrothermal synthesis.

Referring to the production method of the noble metal catalyst characterized by the present invention in more detail as follows.

First, an aluminum compound, a magnesium compound, a Group IIA metal compound, and a Group IIB metal compound are hydrothermally synthesized to prepare a pseudo hydrotalcite precursor. Then, the similar hydrotalcite precursor is dried and calcined to prepare a pseudo hydrotalcite carrier.

That is, the aluminum compound and the magnesium compound are co-precipitated with a carbonate compound at room temperature (15 ° C. to 30 ° C.) at an appropriate ratio, and then, a group IIA metal compound and a group IIB metal compound are added at a desired molar ratio, and the pH is 9 To 11 and then hydrothermally synthesized at a temperature of 120 ° C. to 230 ° C. for 1 to 10 hours to prepare a pseudohydrotalcite precursor. The pseudohydrotalcite precursor is dried at a temperature of 50 ° C. to 90 ° C. and calcined at a temperature of 500 ° C. to 1000 ° C. to prepare a pseudo hydrotalcite carrier (A _x B _y Mg _z / Al).

Then, the impregnated method of the Group VIII noble metal compound of the standard periodic table was impregnated on the pseudohydrotalcite carrier (A _x B _y Mg _z / Al) prepared above, dried at a temperature of 50 ° C to 90 ° C, and then to 500 ° C to It bakes at 1000 degreeC and manufactures the noble metal catalyst which this invention aims at. In the drying process, the water may be gradually evaporated to a temperature of 50 ° C. to 90 ° C. in a water bath, and then the remaining residue may be put into an oven maintained at a temperature of 50 ° C. to 90 ° C. and sufficiently dried.

Metal elements which constitute the pseudohydrotalcite carrier of the present invention are aluminum (Al), magnesium (Mg), group IIA metals, and group IIB metal elements.

The magnesium (Mg) metal element may be supported in a range of 2 to 4 molar ratios, preferably 2 to 3.5 molar ratios, based on the aluminum (Al) metal element.

The Group IIA metal element includes, for example, calcium, strontium, barium, radium, and the like, which may be a single metal or two or more mixed metals. The Group IIA metal element may be supported up to 1 molar ratio based on the aluminum (Al) metal element, preferably 0.01 to 0.7 molar ratio range, more preferably 0.1 to 0.5 molar ratio range.

The Group IIB metal element includes, for example, zinc, cadmium, mercury, and the like, which may be a single metal or two or more mixed metals. The Group IIB metal element may be supported up to 1 molar ratio based on the aluminum (Al) metal element, preferably 0.01 to 0.7 molar ratio range, more preferably 0.1 to 0.5 molar ratio range.

In particular, in forming a pseudo hydrotalcite carrier, the total amount of magnesium, group IIA metals, and group IIB metal elements is fixed in a range of 2 to 5 molar ratios, preferably 4 molar ratios based on 1 mole of aluminum element (Al). good. The reason is that when the total amount of magnesium, group IIA metals and group IIB metal elements is lower than 2 molar ratios based on 1 mole of aluminum element (A1), the effect of addition of these metal elements cannot be expected, and in excess of 5 molar ratios. It is preferable to maintain the above range because the properties of the pseudohydrotalcite precursors decrease, increasing the Group IIA and Group IIB metal oxides, thereby decreasing the activity of the catalyst. In addition, it is preferable to fix the content of magnesium element (Mg) in the range of 25 to 90 mol%, preferably 50 to 90 mol%, in the total amount of magnesium, group IIA metals and group IIB metal elements. The reason for this is that when the magnesium content is less than 25 mol%, the Group IIA metal and the Group IIB metal element are added in excess to decrease the hydrotalcite properties, and when it exceeds 90 mol%, the Group IIA metal and Group IIB are relatively It is preferable to maintain the above range because the amount of the metal element is too small to obtain the addition effect thereof.

In addition, the Group VIII precious metal element as an active ingredient supported on the similar hydrotalcite carrier includes, for example, ruthenium, rhodium, platinum, palladium, iridium, and the like, and these may be single metals or two or more mixed metals. The Group VIIIB metal element may be supported in the range of 0.1 to 20% by weight, preferably 2 to 10% by weight, based on the weight of the pseudohydrotalcite carrier. If the supported amount of the Group VIII metal element is less than the above range, only the dehydration reaction proceeds and the hydrogenation reaction is not performed smoothly, so that the selectivity and yield of 1,2-propanediol may be lowered. In addition, the selectivity and yield of by-products such as ethylene glycol are increased, as well as the catalyst manufacturing cost is increased, thereby reducing economic efficiency.

Metal compounds used for the preparation of the noble metal catalyst of the present invention, for example, magnesium compounds, aluminum compounds, Group IIA metal compounds, Group IIB metal compounds and Group VIIB precious metal compounds include chlorides, oxides, nitrates, sulfates, It can select from acetone salt, an acetate salt, etc., and can use. Although the nitrate compound is mainly illustrated as a metal compound in the Example of this invention, this invention does not specifically limit in selection of such a metal compound.

In addition, a carbonate solution of an alkali metal or an alkaline earth metal such as sodium carbonate or calcium carbonate may be used as the carbonate compound used to provide carbonate ions. Alkaline or alkaline earth metal carbonates may remain after the reaction, causing alkali or alkaline earth metals to remain, which may eventually cause dehydration and hydrogenation of glycerol. Good to do. To this end, after hydrothermal synthesis, the filter is filtered using a vacuum filter and washed several times with distilled water at about 30 ° C to 50 ° C. Considering this point, it is better to use ammonium carbonate as the carbonate compound.

Hydrothermal synthesis temperature control for the preparation of pseudohydrotalcite precursors is also important. As for the temperature of a hydrothermal reaction, 120 degreeC-230 degreeC, Preferably 140 degreeC-200 degreeC, More preferably, 160 degreeC-180 degreeC is suitable. The time of the hydrothermal reaction is suitably 1 to 12 hours, preferably 3 to 8 hours, more preferably 5 to 7 hours. If the temperature of the hydrothermal reaction is too low or the hydrothermal synthesis time is too short, the particle shape and pores of the catalyst may not be uniformly produced, or if the temperature of the hydrothermal reaction is too high or the hydrothermal synthesis time is too long. Not only is the specific surface area of the catalyst drastically reduced, but the particle size of the catalyst is so large that it may not be suitable for the reaction.

In addition, the calcination temperature for preparing the catalyst of the present invention is suitable for 500 ℃ to 1000 ℃, preferably 600 ℃ to 900 ℃, more preferably 700 ℃ to 800 ℃. If the firing temperature is too low, the composite metal oxide particles and pores of the catalyst may be unevenly distributed. If the firing temperature is too high, sintering of the catalyst particles may occur and the surface area may be drastically reduced. The firing time is 1 to 12 hours, preferably 2 to 9 hours, more preferably 4 to 6 hours.

The noble metal catalyst of the present invention prepared through the preparation method as described above has a specific surface area in the range of 90 to 200 m 2 / g. In addition, the carrier constituting the noble metal catalyst of the present invention is a general formula [(M ²⁺ ) _1-x (M ³⁺ ) _x (OH ⁻ ) ₂ ] ^{x +} [(A ⁿ⁻ ) _{x / n} of the hydrotalcite precursor. MH ₂ O and divalent metal (M ²⁺ ) and trivalent metal (M ³⁺ ) have a pseudohydrotalcite structure in which the valence is aligned while forming a brucite-type layer . The carrier precursor formed a relatively even particle shape through hydrothermal synthesis at an appropriate temperature range, and again, a composite metal oxide was formed through calcination and drying after calcination. When a certain amount of precious metal is supported on such a carrier, the catalyst has a similar hydrotalcite structure again due to the inherent memory effect of hydrotalcite, which may be calcined again.

On the other hand, the present invention is characterized by a method for producing 1,2-propanediol from glycerol using the noble metal catalyst prepared above.

More specifically, 1,2-propanediol is prepared by simultaneously performing a dehydration reaction and a hydrogenation reaction of glycerol simultaneously in the presence of a noble metal catalyst and hydrogen. Reactors for the synthesis of 1,2-propanediol are generally used in the art, it is possible to select a batch reactor, a semi-batch reactor, a continuous flow reactor, and the like, and the present invention does not have particular limitations in the selection of such reactors. Do not.

The glycerol used as the reaction raw material may be a high purity product or a crude glycerol containing impurities. For example, crude glycerol from the production of biodiesel may be used. In addition, glycerol may be mixed and used in a solvent, but a solvent which can be used is not particularly limited, and a solvent having a low cost and easy separation from 1,2-propanediol may be selected. Water is most suitable as a solvent which can satisfy this condition. When using a solvent, the concentration of glycerol is maintained in the range of 5 to 85% by weight, preferably in the range of 10 to 75% by weight. If the concentration of glycerol is too high, dehydration condensation may occur between glycerol molecules, and diglycerol, a glycerol dimer, may be produced as a by-product. If the concentration of glycerol is too low, energy for removing solvent from the reaction product may be insufficient. It is not desirable to consume a significant amount.

The amount of the noble metal catalyst used is preferably 0.5 to 90% by weight with respect to glycerol, preferably 1 to 50% by weight, and more preferably 3 to 30% by weight. If the amount of the catalyst is too high, a lot of by-products such as ethylene glycol are generated, which complicates the separation process, and the production cost increases due to excessive use of the catalyst. When the amount of the catalyst is too low, the dehydration of glycerol proceeds but the hydrogenation does not proceed well, so the selectivity and yield of 1,2-propanediol are too low.

The reaction temperature is in the range of 80 ° C to 300 ° C, preferably in the range of 120 ° C to 200 ° C. When the reaction temperature is too high, decomposition of glycerol occurs, thereby increasing the selectivity of the by-products, which is economically undesirable because it consumes a relatively large amount of energy to raise the temperature. If the reaction temperature is too low, the dehydration and hydrogenation of glycerol does not proceed well and the selectivity and yield of 1,2-propanediol are lowered.

The reaction pressure is preferably in the range of 1 to 800 bar, more preferably in the range of 20 to 100 bar. If the reaction pressure is too high, it is not economical because the design cost of the reaction apparatus to withstand high pressure is high, and if the reaction pressure is low, the dehydration and hydrogenation of glycerol are not progressed well and the selectivity of 1,2-propanediol and Yields are low.

The present invention as described above will be described in more detail by the following examples, but the present invention is not limited by these examples.

EXAMPLE

Catalyst Preparation Example 1.

4.45 g of magnesium nitrate and 4.37 g of aluminum nitrate were dissolved in 100 ml of water to prepare an aqueous metal nitrate solution, which was stirred at room temperature for 1 hour. In a separate vessel, 0.96 g of ammonium carbonate was dissolved in 50 ml of water to prepare an aqueous solution of ammonium carbonate and stirred at room temperature for 1 hour. When the ammonium carbonate aqueous solution was added dropwise to the aqueous metal nitrate solution prepared above at a rate of 10 to 20 ml per minute, the reaction product became a translucent white slurry. In this state, the mixture was further stirred for about 2 hours. An aqueous solution of nitrate in which 0.82 g of calcium nitrate and 0.93 g of zinc nitrate was dissolved in 50 ml of water was added to the slurry described above. Then, a small amount of 28% by weight of ammonia water was slowly added to the slurry to gradually produce a white precipitate, and the pH was adjusted to a range of 9 to 10 by continuously adding ammonia. Then further stirred for 2 hours. Then, the product was placed in a hydrothermal reactor having a capacity of 100 ml, and then heated to 160 ° C. for hydrothermal synthesis for 5 hours. After the hydrothermal synthesis was completed, the obtained product was separated by filtration through a reduced pressure filter and washed several times with distilled water at about 40 ° C., and then placed in an oven at 80 ° C. and sufficiently dried. The dried product was processed into a powder form using a mortar and then calcined at 800 ° C. for 5 hours using a combustion furnace in an air atmosphere to obtain a pseudo hydrotalcite carrier.

After taking about 1 g of the similar hydrotalcite carrier prepared above, 0.15 g of ruthenium nitrate (Ru (NO) (NO ₃ ) ₃ ; of which the ruthenium content is about 32% by weight) is 10 ml of distilled water. It was slowly added to the prepared ruthenium aqueous solution dissolved in. In this state, the mixture was stirred for 24 hours. Then, the temperature was raised to 80 ° C. in a water bath to remove some of the water on the slurry, and then sufficiently dried in an oven at 80 ° C. After drying, the mixture was calcined again in an air atmosphere at 800 ° C. for 5 hours to prepare a catalyst having ruthenium supported on a pseudo hydrotalcite carrier.

The catalyst prepared by the above method was named "5 wt% Ru-Ca _0.5 Zn _0.5 Mg ₃ / Al", and the surface area of the catalyst was 129.4 m ² / g.

Catalyst Preparation Example 2.

Manufactured in the same manner as in Preparation Example 1, 5.19 g of magnesium nitrate and 0.82 g of calcium nitrate were used instead of 4.45 g of magnesium nitrate, 0.82 g of calcium nitrate, and 0.93 g of zinc nitrate in the preparation of the pseudohydrotalcite carrier.

The catalyst prepared by the above method was named "5% by weight Ru-Ca _0.5 Mg _3.5 / Al", the surface area of this catalyst was 92.4 m ² / g.

Catalyst Preparation Example 3.

Manufactured in the same manner as in Preparation Example 1, 5.19 g of magnesium nitrate and 0.93 g of zinc nitrate were used instead of 4.45 g of magnesium nitrate, 0.82 g of calcium nitrate, and 0.93 g of zinc nitrate in the preparation of a pseudo hydrotalcite carrier.

The catalyst prepared in the above manner was named "5% by weight Ru-Zn _0.5 Mg _3.5 / Al", the surface area of this catalyst was 121.2 m ² / g.

Catalyst Preparation Example 4.

Prepared in the same manner as in Preparation Example 1, except that 4.45 g of magnesium nitrate, 0.82 g of calcium nitrate, and 0.93 g of zinc nitrate, 2.97 g of magnesium nitrate, 1.65 g of calcium nitrate, and zinc nitrate in the preparation of a pseudo hydrotalcite carrier 1.87 g was used.

The catalyst prepared by the above method was named "5% by weight Ru-Ca ₁ Zn ₁ Mg ₂ / Al", and the surface area of the catalyst was 113.2 m ² / g.

Catalyst Preparation Example 5.

Prepared in the same manner as in Preparation Example 1, the ruthenium nitride nitrate [Ru (NO) (NO ₃ ) ₃ impregnated in a pseudo hydrotalcite carrier; Among them, the ruthenium content was about 32% by weight.

The catalyst prepared by the above method was named "2.5 wt% Ru-Ca _0.5 Zn _0.5 Mg ₃ / Al", and the surface area of the catalyst was 131.5 m ² / g.

Comparative Catalyst Preparation Example 1.

Manufactured in the same manner as in Preparation Example 1, 5.93 g of magnesium nitrate was used in place of 4.45 g of magnesium nitrate, 0.82 g of calcium nitrate, and 0.93 g of zinc nitrate in the preparation of the pseudohydrotalcite carrier.

The catalyst prepared in the above manner was named "5% by weight Ru-Mg ₄ / Al".

Comparative Catalyst Preparation Example 2.

It was prepared in the same manner as in Preparation Example 1, but the ruthenium active ingredient was not added to the pseudo hydrotalcite carrier.

The catalyst prepared in the above manner was named "Ca _0.5 Zn _0.5 Mg ₃ / Al".

Comparative Catalyst Preparation Example 3.

An aqueous solution of 0.31 g of ruthenium nitride nitrate dissolved in 5 ml of distilled water was impregnated into 2 g of γ-alumina (manufactured by STREM) carrier, dried, and calcined at 500 ° C. for 5 hours.

The catalyst prepared in the above manner was named "5 wt% Ru / Al ₂ O ₃ ".

Comparative Catalyst Preparation Example 4.

An aqueous solution of 0.31 g of ruthenium nitride nitrate dissolved in 5 ml of distilled water was impregnated into 2 g of activated carbon (manufactured by Sigma-Aldrich), followed by drying and firing at 400 ° C. for 3 hours in an argon atmosphere.

The catalyst prepared in the above manner was named "5 wt% Ru / C".

Examples 1-5 and Comparative Examples 1-4.

Dehydration and hydrogenation of glycerol in a batch reactor under a high pressure atmosphere were carried out under the following conditions.

50 ml of 20% by weight aqueous solution of glycerol was used as a reactant, and 0.3 g of catalyst was added to a 250 ml autoclave [Parr Co.], and then hydrogen was supplied into the autoclave. Impurities such as air were removed. Hydrogen was then introduced until the internal pressure reached 25 bar. Then, the temperature was gradually increased while stirring at a speed of 200 to 300 rpm until the temperature reached 180 ° C. The reaction was carried out in this state by maintaining for 18 hours. When the reaction temperature is reached, the internal pressure of the autoclave is about 38 to 40 bar. After 3 hours, the internal pressure gradually decreases and at the end of the reaction, about 27 to 30 bar.

The gaseous components remaining after the end of the reaction were taken and gas chromatography with a TCD detector attached and a Carboshpere ™ column was used to analyze the remaining hydrogen and the types of gases that could be produced. After the reaction, the reaction solution remaining in the reactor was separated using a vacuum filter to separate the catalyst and the product, and the product was analyzed using gas chromatography equipped with an FID detector and equipped with an HP-INNOWAX column.

The conversion of glycerol, the selectivity of the product and the yield of 1,2-propanediol at each catalyst condition were calculated by the following equation. The results are summarized in Table 1 below.

[Equation 1]

[Equation 2]

&Quot; (3) &quot;

division catalyst Glycerol Conversion Rate (%) Selectivity of the product (%) 1,2-
Propanediol Yield (%) 1,2-
Propanediol Ethylene glycol methane Other ^(*) Example 1 5 wt% Ru-Ca _0.5 Zn _0.5 Mg ₃ / Al 58.5 85.5 6.6 5.6 2.3 50.0 Example 2 5 wt% Ru-Zn _0.5 Mg _3.5 / Al 55.6 75.1 14.9 5.9 4.1 41.8 Example 3 5 wt% Ru-Ca _0.5 Mg _3.5 / Al 55.7 78.4 13.2 5.6 2.8 43.7 Example 4 5 wt% Ru-Ca ₁ Zn ₁ Mg ₂ / Al 51.5 83.6 7.3 6.0 3.1 43.1 Example 5 2.5% by weight Ru-Ca _0.5 Zn _0.5 Mg ₃ / Al 52.3 86.3 6.8 5.3 1.6 45.1 Comparative Example 1 5 wt%
Ru-Mg ₄ / Al 64.8 62.6 21.3 8.9 7.2 40.6 Comparative Example 2 Ca _0.5 Zn _0.5 Mg ₃ / Al 2.1 47.2 24.1 10.3 18.4 1.0 Comparative Example 3 5 wt.% Ru / Al ₂ O ₃ 45.6 59.2 22.3 11.1 7.4 27.0 Comparative Example 4 5 wt% Ru / C 50.2 53.5 27.1 12.7 6.7 26.7 (*) Sum of selectivity of 1,3-propanediol, acetol, 1-propanol, 2-propanol, propionic acid, ethanol, methanol, etc.

1,2-propane when the reaction was carried out using a catalyst prepared by impregnating 5% by weight of ruthenium in a carrier prepared with a molar ratio of calcium, zinc and magnesium metal elements of 0.5: 0.5: 3. The yield of diol was the highest with 50%. When using the same carrier but using a catalyst prepared by varying the amount of ruthenium supported (Examples 1 and 5), the conversion rate of glycerol tends to increase as the amount of ruthenium supported is increased. On the contrary, the selectivity of 1,2-propanediol tended to decrease slightly. Therefore, it is possible to maintain high catalytic activity while reducing the amount of noble metal supported by the composition change of the carrier.

In the case of the catalyst prepared by adding only one of group IIA element or group IIB element as a carrier composition (Examples 2 and 3), the catalyst prepared by including both group IIA element and group IIB element (Example 1) and In comparison, the conversion rate of glycerol and the selectivity of 1,2-propanediol tended to be somewhat decreased, and the catalyst prepared using Group IIA element among the two elements (Example 3) selected 1,2-propanediol. Degrees and yields were found to be slightly good. Therefore, it was found that the catalyst prepared by simultaneously including group IIA element and group IIB element as a similar hydrotalcite carrier composition has superior catalytic activity as compared to the catalyst which contains each alone.

In the case of the catalyst (Example 4) prepared by increasing the supported amount of group IIA element and group IIB element relative to the catalyst of Example 1 as a carrier composition, the conversion rate of glycerol and the selectivity of 1,2-propanediol and Yield and the like appeared to decrease slightly. Therefore, when the IIA element and the IIB element are included in an appropriate amount as a similar hydrotalcite carrier composition, excellent catalytic activity is described. Was more remarkable.

On the other hand, the catalyst (Comparative Example 1) prepared by including only aluminum and magnesium as a carrier composition, the conversion of glycerol was excellent about 64%, but the selectivity and yield of 1,2-propanediol was low. In the case of the catalyst without the ruthenium active metal (Comparative Example 2), conversion of glycerol hardly occurred.

In addition, in the case of a ruthenium catalyst (Comparative Examples 3 and 4) using alumina or activated carbon as a carrier as a conventional catalyst, the conversion rate of glycerol and the selectivity and yield of 1,2-propanediol were compared with those of Examples 1-5. All were low.

As described above, the noble metal catalyst characterized by the present invention has a high conversion rate of glycerol in the dehydration and hydrogenation of glycerol, and maintains high selectivity and yield of 1,2-propanediol.

Therefore, the noble metal catalyst of the present invention is useful as a catalyst for the reaction process for synthesizing 1,2-propanediol having high added value from glycerol which is a by-product of the biodiesel process.

Claims (7)

A noble metal catalyst for synthesizing 1,2-propanediol, on which a pseudohydrotalcite carrier represented by the following Chemical Formula 1 is supported, one or two noble metal elements selected from Group VIII elements on the standard periodic table:
[Formula 1]
A _x B _y Mg _z / Al
In Formula 1, A is a Group IIA metal element selected from calcium, strontium, barium, and radium; B is a Group IIB metal element selected from zinc, cadmium, and mercury; x, y, and z are molar ratios of aluminum (Al) of each metal element as 0 <x≤1, 0 <y≤1, 2≤z≤4, except that x and y are 0 at the same time. do.
The method according to claim 1,
The Group VIIIB element is a precious metal catalyst, characterized in that selected from ruthenium, rhodium, platinum, palladium, and iridium.
The method according to claim 1 or 2,
The supported amount of the Group VIII element is in the range of 0.1 to 20% by weight based on the weight of the pseudohydrotalcite carrier.
Preparing a hydrotalcite precursor by hydrothermally synthesizing an aluminum compound, a magnesium compound, a Group IIA metal compound, and a Group IIB metal compound at 120 ° C to 230 ° C for 1 to 10 hours;
Drying and calcining the hydrotalcite precursor to prepare a pseudo hydrotalcite carrier having a composition of Formula 1; And
Preparing a precious metal catalyst by impregnating a Group VIIIB precious metal compound on a standard periodic table on the pseudo hydrotalcite carrier;
Method for preparing a noble metal catalyst for 1,2-propanediol synthesis comprising:
[Formula 1]
A _x B _y Mg _z / Al
In Formula 1, A, B, x, y, and z are as defined in claim 1, respectively.
The method of claim 4,
The Group VIIIB precious metal is a ruthenium, rhodium, platinum, palladium, and iridium, characterized in that the production method of 1,2-propanediol noble metal catalyst for the synthesis.
The method according to claim 4 or 5,
The supported amount of the Group VIII precious metal is 0.1 to 20% by weight based on the weight of the pseudohydrotalcite carrier, the method for producing a noble metal catalyst.
Under the noble metal catalyst of any one of claims 1 to 3, glycerol is prepared by performing a dehydration reaction and hydrogenation reaction at 120 ℃ to 230 ℃ temperature and 10 to 800 bar pressure conditions Process for the preparation of propanediol.