JP5179107B2 - Catalyst for hydrogenation - Google Patents

Description

  The present invention relates to a catalyst for hydrogenation of a fatty acid or an ester thereof, a method for producing the same, a method for producing a fatty acid or an ester thereof having a reduced iodine value, and a method for producing an alcohol using the fatty acid or the ester as a raw material. About.

  Fatty acids or esters thereof include unsaturated compounds derived from unsaturated fatty acids such as oleic acid and linoleic acid. Since the content of these unsaturated compounds greatly affects the physical properties of the fatty acid or its ester such as the melting point and oxidation stabilization, the physical properties of the fatty acid or its ester are controlled by appropriately adding hydrogen to form a saturated compound.

It goes without saying that a highly active catalyst is desired as a catalyst used for hydrogenation of fatty acids or esters thereof. Until now, attempts have been made to increase activity by increasing the surface area of pores having a high Ni surface area and a diameter of less than 3 nm with a catalyst in which Ni is supported on SiO ₂ (Patent Document 1). According to this technique, it is disclosed that the hydrogenation activity of the catalyst is increased by providing many pores having a small diameter.
Japanese Patent Laid-Open No. 3-207449

When the hydrogenation of a fatty acid or its ester is carried out industrially, it is an important factor that the high activity lasts for a long time in consideration of economy and convenience of operation. However, although conventional hydrogenation catalysts have high initial activity, there is no mention of sustainability of catalyst activity, and such a highly durable hydrogenation catalyst has been demanded.
That is, an object of the present invention is to provide a catalyst for hydrogenation of a fatty acid or ester thereof having excellent catalytic activity and durability, a method for producing the same, a method for producing a fatty acid or ester thereof having a reduced iodine value, and a raw material thereof. It is to provide a method for producing alcohol.

  As a result of investigations to solve the above-mentioned problems, the present inventors have determined that the capacity of pores containing a specific amount of at least one metal selected from Ni and Cu and having a diameter much larger than that of the prior art. It has been found that increasing the value increases the activity and durability of the hydrogenation catalyst for fatty acids or esters thereof, and is useful for the production of fatty acids or esters thereof with a reduced iodine value.

  That is, the present invention contains 10 to 85% by weight (content as a metal oxide in the total amount of the catalyst) of at least one metal selected from Ni and Cu and has a pore diameter in the range of 20 to 200 nm. Fatty acid or its ester hydrogenation catalyst having a capacity of 0.15 to 1.0 mL / g, its production method, the presence of this hydrogenation catalyst, and the presence of this fatty acid or its ester under the pressure of normal pressure to 30 MPa. Provided are a method for producing a fatty acid or an ester thereof having a reduced iodine value, which performs a hydrogenation reaction, and a method for producing an alcohol in which a reduction reaction is performed using the fatty acid or the ester produced by this method as a raw material.

  By using the hydrogenation catalyst of the present invention, it is possible to efficiently obtain a fatty acid having a low iodine value or an ester thereof over a long period of time. Can be manufactured.

[Hydrogenation catalyst and production method thereof]
The hydrogenation catalyst of the present invention contains at least one metal selected from Ni and Cu. However, from the viewpoint of activity and durability, the metal is preferably Ni alone or a combination of Ni and Cu. .
The content of at least one metal selected from Ni and Cu in the hydrogenation catalyst of the present invention is 10% by weight or more, preferably 55% by weight or more, preferably 60% by weight from the viewpoints of activity and durability. The above is more preferable, and 65% by weight or more is still more preferable. Further, from the viewpoint of the strength of the catalyst, it is 85% by weight or less, and preferably 80% by weight or less.
The metal content here is the content as a metal oxide in the total amount of the catalyst containing a carrier, a binder and other components.

  The hydrogenation catalyst of the present invention has a pore volume in the range of a pore diameter of 20 to 200 nm of 0.15 mL / g or more and 0.18 mL / g from the viewpoint of developing sufficient hydrogenation activity and durability. The above is preferable, 0.20 mL / g or more is more preferable, and 0.25 mL / g or more is still more preferable. Further, when used as a molded body, from the viewpoint that the reaction vessel can be designed in a compact manner, the bulk density is preferably higher to some extent, so the pore volume in the range of pore diameters of 20 to 200 nm is 1.0 mL / g or less, 0.7 mL / g or less is preferable.

Note that the pore diameter is a diameter measured by a mercury intrusion method, and the mode diameter of the pore diameter measured by the mercury intrusion method of the hydrogenation catalyst of the present invention is a viewpoint of developing sufficient hydrogenation activity and durability. Therefore, 20 nm or more is preferable, and 30 nm or more is more preferable. Moreover, from a viewpoint of the intensity | strength of a catalyst, 200 nm or less is preferable and 100 nm or less is more preferable.
As the mercury intrusion measuring apparatus, for example, Pore Sizer 9320 manufactured by Micromeritics can be used. The maximum pressure of mercury intrusion is 207 MPa, and pores larger than 6 nm are measured.

  The hydrogenation catalyst of the present invention can have good hydrogenation activity and durability by controlling the volume of pores having a diameter in the range of 20 to 200 nm to be in the above range. The pore structure of the catalyst can be controlled by variously changing catalyst preparation conditions such as precipitation conditions, drying conditions, molding conditions, and calcination conditions.

As described above, in the hydrogenation catalyst of the present invention, pores having a diameter of 20 nm to 200 nm are important, and this determines the hydrogenation activity and durability. Therefore, it is better that the proportion of the small pores having a diameter of less than 20 nm in the whole is small, and in particular, the surface area (BET specific surface area) of the pores having a diameter of less than 3 nm is preferably less than 55% of the total surface area.
Note that the surface area of pores having a diameter of less than 3 nm refers to a value obtained by the BET method using nitrogen adsorption. The BET specific surface area can be measured by, for example, ASAP2020 manufactured by Micromeritics.

Further, the hydrogenation catalyst of the present invention is preferably one in which at least one metal selected from Ni and Cu is supported on a carrier.
As the carrier, known carriers such as silica, alumina, silica alumina, zeolite, diatomaceous earth, activated clay, titania, zirconia, activated carbon and the like can be used, but silica, alumina, silica alumina, titania, zirconia are preferable, silica, alumina, Silica alumina is more preferred.

  The method for supporting at least one metal selected from Ni and Cu on the support is not particularly limited, and a coprecipitation method, an impregnation method, a uniform kneading method, or the like can be applied. These preparation methods can also be applied in combination. Among these, the coprecipitation method and the impregnation method are preferable, and the coprecipitation method is more preferable.

  In the case of the coprecipitation method, for example, an aqueous solution in which at least one selected from a water-soluble Ni salt and a water-soluble Cu salt is dissolved, an aqueous solution of a substance serving as a carrier, and an aqueous alkali metal salt solution are mixed to simultaneously precipitate a metal and a carrier. The obtained precipitate can be washed, dried and fired. The pH during precipitation is preferably 5-10.

  In the case of the impregnation method, for example, a method of impregnating a carrier powder with an aqueous solution in which at least one selected from a water-soluble Ni salt and a water-soluble Cu salt is dissolved, and drying and baking can be used.

  As a method for producing a hydrogenation catalyst of the present invention, an aqueous solution of at least one salt selected from a Ni salt and a Cu salt is used as a solid during precipitation from the viewpoint of productivity and ease of controlling the pore structure of the catalyst. Precipitation is preferably performed under a condition that the partial concentration (the resulting precipitate is converted to a metal oxide) is 1 to 20% by weight, more preferably 2 to 20% by weight, and more preferably 3 to 20% by weight. Conditions are more preferred. By precipitating at a high concentration, the volume of pores having a large diameter can be increased. Here, solid content concentration refers to the case where all the solids obtained after filtration are converted as metal oxides.

  The temperature during precipitation is preferably 55 ° C. or higher, more preferably 65 ° C. or higher, and still more preferably 70 ° C. or higher, from the viewpoint of easy control of the pore structure of the catalyst. Moreover, from a viewpoint of manufacturing equipment load and manufacturing cost, 100 degrees C or less is preferable, 95 degrees C or less is more preferable, and 90 degrees C or less is still more preferable. By carrying out the precipitation at a high temperature, the capacity of pores having a large diameter can be increased.

  The shape of the catalyst can be appropriately selected according to the reactor configuration from powder, granule, or spherical or columnar shape depending on the reaction system. From the viewpoint of reducing the pressure loss when the fluid passes through the catalyst, a granular or molded shape is preferable.

  These catalysts are usually used after reduction activation with hydrogen. Further, a catalyst that has been subjected to reduction activation and stabilization treatment in advance may be used as it is or after reduction activation again.

[Method for producing fatty acid or ester thereof]
The method for producing a fatty acid or an ester thereof according to the present invention includes a fatty acid having a reduced iodine value by performing a hydrogenation reaction of the fatty acid or an ester thereof under normal pressure to 30 MPa in the presence of the hydrogenation catalyst of the present invention. A method for producing the ester.
Distillation can also be performed for the purpose of impurity removal or purification before or after hydrogenation.

Examples of the fatty acid or ester thereof as a raw material include triglyceride (oil and fat), diglyceride, monoglyceride, fatty acid, ester of fatty acid and alcohol having 1 to 22 carbon atoms (hereinafter referred to as fatty acid alcohol ester), and the like. Among these, as glycerides, animal fats such as beef tallow and fish oil, vegetable oils such as palm kernel oil, coconut oil, palm oil, soybean oil, rapeseed oil, and diglycerides and monoglycerides derived therefrom Is mentioned. Among these, those having 8 to 22 carbon atoms as constituent fatty acids are preferred, and those derived from vegetable glycerides are particularly preferred.
Fatty acids can be obtained by hydrolysis of fats and oils. Examples of the hydrolysis method include a high-pressure continuous decomposition method, a medium-pressure method, and an enzyme method.

  The fatty acid alcohol ester can be obtained by an ester exchange reaction between the glycerides and an alcohol having 1 to 22 carbon atoms, or an esterification reaction between a fatty acid derived from the glycerides and an alcohol having 1 to 22 carbon atoms. I can do it. The alcohol used here is preferably a lower alcohol having 1 to 4 carbon atoms.

  The transesterification reaction and esterification reaction can be carried out by known methods. The reaction can be performed in either a continuous or batch mode, but a continuous reaction is advantageous when a large amount of ester is produced. As the catalyst, a homogeneous alkaline catalyst such as sodium hydroxide, potassium hydroxide or sodium alcoholate is generally used, but solid catalysts such as ion exchange resin, hydrous zirconium oxide, aluminum phosphate, sulfuric acid-supported zirconia, titanosilicate, etc. Can also be used. When using a homogeneous alkali catalyst, the reaction is generally carried out under the following conditions. The reaction temperature is 30 to 90 ° C., preferably 40 to 80 ° C., and the reaction pressure is in the range of normal pressure to 0.5 MPa, preferably normal pressure. Moreover, the usage-amount of alcohol has a preferable 1.5-10 mol times with respect to glycerides from a viewpoint of cost and reactivity. When free fatty acids are contained in the glycerides, it is also effective to esterify the fatty acid in advance using an acid catalyst such as sulfuric acid or paratoluenesulfonic acid before performing the transesterification reaction with an alkali catalyst. .

  As a method of hydrogenation reaction of the raw material fatty acid or its ester obtained as described above, either a batch method or a continuous method can be used. In addition, any commonly used method such as a suspension method using a powder catalyst or a fixed bed method using a molded catalyst can be used. When processing in large quantities, a continuous fixed bed system is advantageous.

 The atmosphere gas for the hydrogenation reaction is preferably hydrogen, and an inert gas may coexist. Inert gases include nitrogen, argon, helium and methane. The pressure of the atmospheric gas is normal pressure to 30 MPa, preferably 0.01 to 30 MPa, and more preferably 0.1 to 30 MPa. When the reaction is carried out continuously, the flow rate of the atmospheric gas is preferably in the range of 0.1 to 300 times the molar ratio of hydrogen to the number of moles of raw material fatty acid or ester to be treated.

  The temperature of the hydrogenation reaction is preferably 40 ° C or higher, more preferably 50 ° C or higher, from the viewpoint of obtaining a sufficient hydrogenation rate. Moreover, from a viewpoint of suppressing side reactions, such as hydrogenolysis of raw material fatty acid or its ester, 200 degrees C or less is preferable and 180 degrees C or less is still more preferable.

  When the hydrogenation reaction is carried out continuously, the flow rate of the raw fatty acid or ester thereof is appropriately set from the viewpoints of productivity, catalyst life, suppression of hydrocracking, etc., but the reaction tower volume per hour The ratio (LHSV) is preferably 0.1 or more, and LHSV is preferably 5 or less from the viewpoint of obtaining sufficient activity.

  By hydrogenation under the above conditions, a fatty acid or an ester thereof having a reduced iodine value can be obtained. For example, when the raw material is a fatty acid alcohol ester, the iodine value after the hydrogenation treatment can be 5 or less.

[Method for producing alcohol]
The method for producing an alcohol of the present invention is a method for obtaining an alcohol by performing a reduction reaction using a fatty acid or an ester thereof having a reduced iodine value produced by the method of the present invention as described above as a raw material.
Moreover, you may perform continuously the method of obtaining the fatty acid by which iodine value was reduced by said hydrogenation reaction, or its ester, and the method of obtaining alcohol by a reductive reaction.

  As a catalyst used for the production of alcohol, generally known copper-based or noble metal-based catalysts such as palladium and platinum are used. Examples of the copper-based catalyst include copper-chromium, copper-zinc, copper-iron-aluminum, and copper-silica. In the presence of these catalysts, the reduction reaction can be carried out by any commonly used reaction method such as a liquid phase suspension bed or a fixed bed method.

  When the reduction reaction is carried out in the liquid phase suspension bed system, the catalyst amount is preferably 0.1 to 20% by weight based on the fatty acid or its ester, but depending on the reaction temperature or reaction pressure, a practical reaction yield may be obtained. It can be arbitrarily selected within the range obtained. The reaction temperature is preferably 160 to 350 ° C, more preferably 200 to 280 ° C. The reaction pressure is preferably 0.1 to 35 MPa, more preferably 3 to 30 MPa.

  When the reduction reaction is carried out continuously in a fixed bed system, the catalyst used is a cylinder, pellet, or sphere. The reaction temperature is preferably 130 to 300 ° C, more preferably 150 to 270 ° C, and the reaction pressure is preferably 0.1 to 30 MPa. LHSV is arbitrarily determined according to reaction conditions in consideration of productivity and reactivity.

  In the following examples, the pore volume in the pore diameter range of 20 to 200 nm of the catalyst and the mode diameter of the pore diameter were measured with a pore sizer 9320 manufactured by Micromeritics, which is a mercury intrusion measuring apparatus. The iodine value of the fatty acid ester was measured by the Wijs method (JIS K0070: 1992).

Preparation Example of Raw Fatty Acid Ester To 1000 g of palm kernel oil, 30 g of methanol solution containing 10% by weight of NaOH and 100 g of methanol were added in three portions while removing the glycerin layer produced, and at 50 ° C. The reaction was performed for 3 hours. After the reaction, the oil layer was washed with water to obtain palm kernel oil fatty acid methyl ester. The obtained palm kernel oil fatty acid methyl ester was further distilled to obtain a palm kernel oil fatty acid methyl ester having an iodine value of 17.5. In the following examples, this palm kernel oil fatty acid methyl ester was used as a raw material.

Catalyst production example 1
A 2 L separable flask was charged with 800 g of ion exchanged water and 232 g of Ni (NO ₃ ) ₂ .6H ₂ O, and the temperature was raised to 80 ° C. while stirring. Here, ion-exchanged water 630g in JIS3 water glass 33 g, the solution was heated to 80 ° C. to dissolve the Na ₂ CO ₃ 113 g, it was charged with stirring. After the addition, 24 g of Mg (NO ₃ ) ₂ .6H ₂ O was added, and the resulting slurry was stirred at 80 ° C. for 1 hour, filtered, washed with water, and dried at 110 ° C. to obtain a precursor. The solid content concentration (as oxide) at the time of precipitation was 6.1% by weight. Next, after the precursor was formed into a noodle shape using alumina as a binder, firing, reduction, and stabilization were performed to obtain a catalyst A having a diameter of 1.6 mm. The pore volume of the catalyst A having a pore diameter of 20 to 200 nm was 0.361 mL / g.

Catalyst production example 2
A 2 L separable flask is charged with 840 g of ion-exchanged water, 180 g of Ni (NO ₃ ) ₂ .6H ₂ O, 22 g of Cu (NO ₃ ) ₂ .3H ₂ O, 4 g of γ-alumina, and 4.7 g of 60% nitric acid. The temperature was raised to 80 ° C. A solution prepared by dissolving 50 g of JIS No. 3 water glass and 118 g of Na ₂ CO _{3 in} 570 g of ion-exchanged water and heating to 80 ° C. was added thereto with stirring. The resulting slurry was stirred at 80 ° C. for 1 hour, filtered, washed with water, and dried at 110 ° C. to obtain a precursor. The solid content concentration (as oxide) at the time of precipitation was 4.1% by weight. Next, the precursor was formed into a noodle shape using alumina as a binder, and then calcined, reduced, and stabilized to obtain a catalyst B having a diameter of 1.6 mm. The pore volume of this catalyst B in the pore diameter range of 20 to 200 nm was 0.325 mL / g.

Catalyst production example 3
A 2 L separable flask is charged with 1260 g of ion-exchanged water, 108 g of Ni (NO ₃ ) ₂ .6H ₂ O, 13 g of Cu (NO ₃ ) ₂ .3H ₂ O, 2.4 g of γ-alumina, and 2.8 g of 60% nitric acid. The temperature was raised to 80 ° C. with stirring. A solution prepared by dissolving 30 g of JIS No. 3 water glass and 71 g of Na ₂ CO _{3 in} 860 g of ion-exchanged water and heating to 80 ° C. was added thereto with stirring. The resulting slurry was stirred at 80 ° C. for 1 hour, filtered, washed with water, and dried at 110 ° C. to obtain a precursor. The solid content concentration (as oxide) at the time of precipitation was 1.8% by weight. Next, the precursor was formed into a noodle shape using alumina as a binder, and then calcined, reduced, and stabilized to obtain a catalyst C having a diameter of 1.6 mm. The pore volume of the catalyst C having a pore diameter in the range of 20 to 200 nm was 0.182 mL / g.

Comparative production example 1 of catalyst
After preparing a dry precursor by preparing in the same manner as in Production Example 3, the kneading time before molding was extended to obtain Catalyst D. The pore volume of the catalyst D having a pore diameter in the range of 20 to 200 nm was 0.095 mL / g.

Comparative production example 2 of catalyst
A catalyst E was prepared in the same manner as in Production Example 3 except that the temperature at the time of charging the raw material and stirring the slurry was changed from 80 ° C. to 50 ° C. The pore volume of the catalyst E having a pore diameter in the range of 20 to 200 nm was 0.081 mL / g.

Table 1 summarizes the metal contents of the catalysts A to E obtained in the above production examples and comparative production examples, the pore volume in the range of pore diameters of 20 to 200 nm, and the mode diameters of the pore diameters.
For catalyst A, the BET specific surface area within a pore diameter range of less than 3 nm was measured by ASAP2020 manufactured by Micromeritics. The results are also shown in Table 1.

Examples 1 to 3 and Comparative Examples 1 and 2
An autoclave with an internal volume of 500 mL was charged with 2 g of catalysts A to E and 200 g of palm kernel oil fatty acid methyl ester (iodine value 17.5) obtained in the above preparation example, 135 ° C., hydrogen pressure 24.5 MPa, hydrogen flow rate 5 L / min. Under these conditions, the hydrogenation reaction was carried out for 60 minutes, assuming that the time when the temperature reached 135 ° C. was 0 minutes. Table 2 shows the iodine value of palm kernel oil fatty acid methyl ester at 0 minutes and 60 minutes and hydrogenation activity 1 calculated by the following formula.

  Hydrogenation activity 1 = LN (iodine number for reaction 0 minutes / iodine number for reaction 60 minutes)

Examples 4 to 6 and Comparative Example 3
The catalyst A to D 180 mL was charged into a fixed bed reactor, and the palm kernel oil fatty acid methyl ester (iodine value 17.5) obtained in the above preparation example was 900 mL / hour (LHSV = 5) Hydrogen 1900 NL / hour was simultaneously supplied from the upper part of the reactor to carry out a hydrogenation reaction. Palm iodine oil fatty acid methyl ester collected immediately after passing through and 1000 times after passing through, iodine value of palm kernel oil fatty acid methyl ester immediately after passing through and after 1000 times passing through, hydrogenation activity calculated by the following formula 2 and 3 are shown in Table 3, respectively.

Hydrogenation activity 2 = LN (iodine value before treatment ^{* 1} / iodine value immediately after passing through)
Hydrogenation activity 3 = LN (iodine value before treatment ^{* 1} / iodine value after passing 1000 times)
* 1: Raw material iodine value = 17.5

Example 7 (Example of alcohol production)
Using a fixed bed reactor, a hydrogenation reaction and a reduction reaction of the palm kernel oil fatty acid methyl ester (iodine value 17.5) obtained in the above preparation example were continuously performed. The fixed bed reactor is equipped with two reactors in series. The first reactor is charged with 360 mL of catalyst A, and the second reactor is charged with 360 mL of a titania-supported copper-zinc catalyst (composition: Cu = 35%, Zn = 1.8%, TiO ₂ carrier 50%, shape: 3.2 mmφ × 3.2 mm cylindrical shape). The hydrogenation reaction conditions of the first reactor were 20 MPa and 90 ° C., and the flow rate of palm kernel oil fatty acid methyl ester was 260 mL / hour (LHSV = 0.72). The iodine value of palm kernel oil fatty acid methyl ester after being treated in the first reactor was 0.01.

  The reduction reaction conditions of the second reactor filled with the reduction catalyst were a pressure of 20 MPa and a temperature of 210 ° C. After the reduction reaction, the alcohol content in the obtained liquid was 96.8% on gas chromatography, and the saponification value was 4.7 mg-KOH / g.

Claims (8)

  It contains 10 to 85% by weight of Ni (content as a metal oxide in the total amount of the catalyst), and the pore volume in the range of pore diameters of 20 to 200 nm is 0.15 to 1.0 mL / g. A catalyst for hydrogenation of a fatty acid or an ester thereof, having a pore diameter mode diameter of 20 to 200 nm and having a molded shape.   The hydrogenation catalyst according to claim 1, which has a shape formed into a spherical shape or a column shape.   The hydrogenation catalyst according to claim 1 or 2, wherein the catalyst is formed using alumina as a binder.   An aqueous solution of at least one salt selected from Ni salts is precipitated under conditions such that the solid content concentration during precipitation (the obtained precipitate is converted to a metal oxide) is 1 to 20% by weight. 4. The method for producing a hydrogenation catalyst according to any one of 3 above.   The manufacturing method of the catalyst for hydrogenation of Claim 4 which precipitates at the temperature of 55-100 degreeC.   The method for producing a hydrogenation catalyst according to claim 4 or 5, further comprising a step of forming a precipitate.   In the presence of the hydrogenation catalyst according to any one of claims 1 to 3, a hydrogenation reaction of a fatty acid or an ester thereof is performed under a pressure of normal pressure to 30 MPa. Production method. The production method according to claim 7, wherein the fatty acid or an ester thereof is at least one selected from triglycerides, diglycerides, monoglycerides, fatty acids, and esters of fatty acids and alcohols having 1 to 22 carbon atoms.