JP2007175563A - Method for producing monounsaturated fatty acid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrogenation catalyst for producing a high-quality monounsaturated fatty acid having low content of polyunsaturated fatty acids such as linoleic acid, low content of saturated fatty acids and low content of trans-fatty acids, and a method for producing the high-quality monounsaturated fatty acid. <P>SOLUTION: The hydrogenation catalyst contains copper and at least one element selected from group A consisting of molybdenum, zirconium, vanadium, gallium and elements of group III in the periodic table and is used for producing the monounsaturated fatty acid from a polyunsaturated fatty acid. The method for producing the monounsaturated fatty acid comprises a step of hydrogenating a raw material fatty acid containing polyunsaturated fatty acids by using the hydrogenation catalyst. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing high-quality monounsaturated fatty acids that are widely used as raw materials for lubricants, plasticizers, oils, emulsifiers, detergents, and the like.

  Monounsaturated fatty acids, such as oleic acid, are generally obtained by distilling fatty acids obtained by hydrolyzing oils and fats such as beef tallow into liquid acids and solid acids, and then distilling the obtained liquid acids to obtain all distillates. It is manufactured by doing. However, oleic acid produced by this method contains polyunsaturated fatty acids such as linoleic acid, which not only lowers the purity of oleic acid, but also causes quality deterioration such as hue, odor, and oxidation stability. Therefore, improvement has been desired from the past.

  Methods for removing polyunsaturated fatty acids such as linoleic acid in oleic acid include purification methods such as chromatographic separation and urea addition, and methods for selectively hydrogenating polyunsaturated fatty acids using a catalyst. There is.

  However, purification methods such as chromatographic separation methods and urea addition methods are not satisfactory as industrial production methods in terms of production cost, throughput, and the like.

  On the other hand, as a method for producing oleic acid by hydrogenation using a catalyst, a method using a fat or fatty acid or an ester thereof as a raw material and a solid catalyst such as nickel, palladium, rhodium or copper as a catalyst has been studied. . Copper catalysts have the advantages that they are less expensive and produce less saturated fatty acids than other solid catalysts.

However, copper is easy to elute into fatty acid as a hydrogenation raw material, and easily forms copper soap. Moreover, the copper metal produced | generated when the formed copper soap is hydrogenated easily aggregates, and catalyst activity falls. In order to overcome this problem, as a method of using a copper-containing catalyst, a method of reducing and activating in advance in an inert liquid such as an aliphatic alcohol or a fatty acid ester has been disclosed (Patent Document 1). However, in this method, by using liquids other than the reaction raw materials, equipment such as a reaction tank for reduction activation and separation equipment for the catalyst after reduction activation are required, and cost, labor, production capacity, etc. There was a problem.
JP-A-8-99036

  An object of the present invention is to provide a hydrogenation catalyst for producing a high-quality monounsaturated fatty acid having a low content of polyunsaturated fatty acids such as linoleic acid, a low content of saturated fatty acids, and a low content of trans acids, as well as a high-quality mono It is providing the manufacturing method of an unsaturated fatty acid.

The present invention provides a catalyst for hydrogenation of polyunsaturated fatty acids to monounsaturated fatty acids containing copper and at least one element selected from the following group A, and a catalyst for hydrogenation using the hydrogenation catalyst. Provided is a method for producing a monounsaturated fatty acid in which a raw fatty acid containing an unsaturated fatty acid is hydrogenated.
Group A: Molybdenum, zirconium, vanadium, gallium, and elements of Group 3 of the periodic table

  According to the present invention, it is possible to produce a high-quality monounsaturated fatty acid having a reduced content of polyunsaturated fatty acids and a low content of saturated fatty acids and a low content of trans acids.

[Hydrogenation catalyst and its production method]
The hydrogenation catalyst used in the present invention contains copper and at least one element selected from the above group A.

  Group A elements include elements of Group 3 of the periodic table such as molybdenum, zirconium, vanadium, gallium, scandium, yttrium, lanthanoid elements, and actinoid elements. Among them, molybdenum, zirconium, yttrium, and lanthanum are included. Molybdenum, zirconium and yttrium are more preferable.

  The weight ratio of copper to the group A element in the hydrogenation catalyst of the present invention is preferably in the range of copper / (group A element) = 100 / 0.1 to 100/80, preferably 100/1 to 100/80. A range of 50 is more preferred.

  The hydrogenation catalyst of the present invention can be produced by the following methods (1) to (3).

(1) Impregnation supporting method The impregnation supporting method is a hydrogenation catalyst in which a metal oxide of at least one element selected from Group A is impregnated and supported on a copper oxide, hydroxide, carbonate or a mixture thereof. Is the way to get.

  Specifically, for example, a precipitate is obtained by mixing a metal salt aqueous solution containing copper and a precipitating agent, followed by filtration, washing with water, drying, firing, or oxidation of copper obtained by combining these steps. A hydrogenation catalyst is obtained by impregnating and supporting a metal salt of at least one element selected from Group A on a product, hydroxide, carbonate or a mixture thereof. Examples of the precipitant used here include aqueous alkali solutions such as sodium carbonate, ammonium carbonate, sodium hydrogen carbonate, sodium hydroxide, potassium hydroxide, ammonia, and urea.

  The impregnating and supporting method comprises contacting an aqueous solution of a metal salt of at least one element selected from Group A with a copper oxide, hydroxide, carbonate or a mixture thereof, and then drying the moisture. The method of removing by is mentioned. The impregnated supported catalyst obtained by drying may be further calcined.

(2) Coprecipitation method In the coprecipitation method, a hydrogenation catalyst is obtained by forming a precipitate with a precipitant from a mixed aqueous solution containing a metal salt of copper and a metal salt of at least one element selected from group A. Is the method.

  Specifically, a precipitate is obtained by mixing a copper metal salt, a mixed aqueous solution containing a metal salt of at least one element selected from Group A, and a precipitant, followed by filtration, washing with water, and drying. , Calcination, or a combination of these processes to obtain a hydrogenation catalyst.

  Examples of the precipitating agent used here are the same as those in the method (1).

(3) Coprecipitation method by alkoxide hydrolysis In the coprecipitation method by alkoxide hydrolysis, a hydrogenation catalyst is obtained by forming a precipitate from a solution of copper and at least one metal selected from Group A. Is the method.

  Specifically, a solution of an alkoxide of copper and at least one metal selected from group A is mixed with water or an acid or basic aqueous solution to obtain a precipitate, followed by filtration, washing with water, A hydrogenation catalyst is obtained by drying, calcination, or a combination of these steps.

  Among the production methods (1) to (3), the impregnation supporting method (1) and the coprecipitation method (2) are preferable, and the impregnation supporting method (1) is more preferable.

  Any metal salt can be used as long as it is water-soluble. For example, metal salts of copper, yttrium, lanthanum, and cerium include nitrates, sulfates, ammonium complexes, acetates, oxalates, and chlorides, and metal salts of molybdenum and vanadium include ammonium salts and chlorides. Zirconium metal salts include nitrates, oxynitrates, sulfates, acetates and chlorides, scandium metal salts include nitrates, acetates and chlorides, and gallium metal salts include nitrates and chlorides. Things are used.

  Drying and baking are preferably performed at 20 ° C to 700 ° C, more preferably 20 ° C to 400 ° C. The pressure is not particularly limited, but from the viewpoint of production time, when drying at a low temperature, for example, 90 ° C. or less, it is preferably performed under reduced pressure.

  The hydrogenation catalyst of the present invention may be supported on a carrier. Specific examples of the carrier include titania, zirconia, diatomaceous earth, silica, silica alumina, alumina, niobia, activated carbon and the like.

  In the case of the impregnation support method, a precipitate is obtained by mixing a copper metal salt aqueous solution and a precipitating agent in the presence of a carrier, followed by filtration, washing with water, drying, firing, or a combination of these steps. A copper / support oxide, hydroxide, carbonate or mixture thereof impregnated with a metal salt of at least one element selected from group A to produce a hydrogenation catalyst supported on the support Is done.

  In the case of the coprecipitation method, in the presence of a carrier, a precipitate is obtained by mixing a copper metal salt, a mixed aqueous solution containing a metal salt of at least one element selected from Group A, and a precipitant, Subsequently, a hydrogenation catalyst supported on a carrier is produced by filtering, washing with water, drying, calcination, or a combination of these processes.

[Reduction activation method of hydrogenation catalyst]
When hydrogenating a polyunsaturated fatty acid, the reduction of the catalyst may be performed in an inert liquid, but it is performed in a raw fatty acid for producing a monounsaturated fatty acid by a hydrogenation reaction. However, there is no problem, and in this case, it is preferable because reduction activation and hydrogenation of the catalyst can be performed continuously.

  When the raw fatty acid for producing the monounsaturated fatty acid by the hydrogenation reaction is used as the reduction activation fatty acid of the catalyst, a method of circulating a gas through the mixture of the raw fatty acid and the catalyst is simple and preferable.

  As the gas used here (hereinafter referred to as circulation gas), hydrogen gas used for reduction may be used, or a mixed gas of hydrogen gas and inert gas may be used. The flow rate of the flow gas is not particularly limited, but it is preferable to flow 5 mol per hour (hereinafter referred to as 5 mol / mol / h) or more per 1 mol of copper, and more preferably 10 mol / mol / h or more. More preferably 20 mol / mol / h or more. The upper limit of the flow rate is not particularly limited, but is preferably 600 mol / mol / h or less, and more preferably 300 mol / mol / h or less in consideration of economy, volatilization of fatty acids or entrainment of droplets. As the inert gas, argon, nitrogen and the like are preferable, and nitrogen gas is more preferable. When a mixed gas of hydrogen gas and inert gas is used, the ratio of hydrogen gas to inert gas is preferably such that the hydrogen gas / inert gas ratio is 0.01 mol / mol or more, and 0.1 mol / mol The above is more preferable.

  The temperature at which gas circulation starts is preferably in the range of 20 to 190 ° C, more preferably in the range of 50 to 180 ° C. After starting the gas flow, the reduction activation can be performed while keeping the temperature constant, but the reduction activation can also be performed while the temperature rise is continued. In this case, the heating rate is preferably 100 ° C./h or less, and more preferably 70 ° C./h or less. In order to sufficiently perform the reduction activation, the maximum temperature during the gas flow is preferably 120 ° C. or higher, and more preferably 150 ° C. or higher. On the other hand, in order to suppress thermal degradation of the catalyst, 300 ° C. or lower is preferable, and 250 ° C. or lower is more preferable. The reduction activation time is not particularly limited, but is preferably 20 minutes or more, and more preferably 40 minutes or more. Although an upper limit is not specifically limited, 10 hours or less are preferable. Although the pressure in a reduction activation process is not specifically limited, Normal pressure-5 Mpa * G are preferable, More preferably, they are normal pressure-3 Mpa * G.

[Method for producing monounsaturated fatty acid]
The method for producing a monounsaturated fatty acid according to the present invention is a method for producing a monounsaturated fatty acid by hydrogenating a raw fatty acid containing a polyunsaturated fatty acid using the hydrogenation catalyst according to the present invention. It is suitably used when high-quality oleic acid is produced by hydrogenating raw fatty acids containing polyunsaturated fatty acids such as linoleic acid.

  The raw fatty acid used for the production of oleic acid can be obtained by hydrolyzing the raw oil and fat into fatty acid and glycerin. Raw oils and fats include beef tallow, sheep fat, pork tallow, chicken tallow, palm oil, palm oil, palm stearin or palm olein, high oleic sunflower oil, high oleic sunflower oil, peanut oil, soybean oil, palm Animal and vegetable oils such as oil, cottonseed oil, rapeseed oil, and palm kernel oil can be used. Is preferred.

  As a method for hydrolysis of raw material fats and oils, it can be carried out by a known method, and specifically, it can be carried out by a method generally used for industrialization such as a high-pressure continuous decomposition method, a medium-pressure method, an enzyme method or the like. . The fatty acid thus obtained may be distilled according to known methods and conditions, if necessary. For example, when fats and oils containing a large amount of fatty acids other than fatty acids having 18 carbon atoms are hydrolyzed, distillation is performed at this stage to obtain fatty acids mainly composed of fatty acids having 18 carbon atoms. By subjecting it to the step of fractionating into solid acid, the target raw material fatty acid for producing oleic acid can be more efficiently produced.

  As a method of fractionating into a liquid acid and a solid acid, it can be carried out by a generally industrially utilized method such as a solvent fractionation method or an activator fractionation method. The liquid acid thus obtained may be distilled according to known methods and conditions, if necessary.

  Next, the raw fatty acid thus obtained is hydrogenated using the hydrogenation catalyst according to the present invention. If the amount of the catalyst is too large, or if the temperature or hydrogen pressure is too high, the production of saturated fatty acids increases, and if the temperature is too low, the hydrogenation activity decreases and a long time is required for the reaction. From this viewpoint, the amount of the catalyst used is preferably 0.1 to 5% by weight, more preferably 0.2 to 4% by weight, based on the raw fatty acid.

  The hydrogenation reaction temperature is preferably 120 ° C to 280 ° C, and more preferably 150 to 230 ° C. The hydrogen pressure is preferably from normal pressure to 3 MPa · G, more preferably from normal pressure to 1 MPa · G. The hydrogenation reaction can be used under the flow of hydrogen gas or under the hydrogen gas atmosphere sealing conditions. The completion of the reaction can be appropriately determined from the amount of polyunsaturated fatty acid remaining and the amount of saturated fatty acid.

  In the following examples,% is% by weight unless otherwise specified. Cm: n means a fatty acid having m carbon atoms and n double bonds. The fatty acid composition was determined by gas chromatography analysis after methylation with diazomethane.

  Liquid acids 1 to 3 used as raw material fatty acids in the following examples were obtained by fractionating beef tallow fatty acids obtained by high-pressure hydrolysis of beef tallow by a conventional method using an activator method. The fatty acid composition was as shown in Table 1.

Example 1
A 15% copper nitrate aqueous solution was dropped into a 9% sodium carbonate aqueous solution at room temperature to obtain a slurry. The pH after completion of the dropwise addition was 7.0. The precipitate was filtered off from this slurry, sufficiently washed with water, and then dried at 120 ° C. for 14 hours to obtain a powder. 10.43 g of this powder was suspended in water, an aqueous solution of 0.55 g of ammonium molybdate was added thereto and stirred at room temperature, and then water was distilled off at 70 ° C. with an evaporator. The obtained solid was dried at 120 ° C. for 14 hours and then calcined at 300 ° C. for 2 hours to obtain a catalyst (weight ratio: copper / molybdenum = 100 / 5.0). Using 0.57% (vs. liquid acid) of this catalyst, the temperature was raised from room temperature to 170 ° C. in a liquid acid 1 having the composition shown in Table 1 under a hydrogen 0.01 MPa · G sealed condition. After reaching 170 ° C., hydrogen flow was started, and the catalyst was reduced and activated for 1 hour at a normal temperature and a heating rate of 30 ° C./h under hydrogen flow of hydrogen / copper = 25 mol / mol / h. Thereafter, hydrogenation was carried out for 4 hours under sealed conditions of 200 ° C. and 0.40 MPa · G. The composition of the fatty acid rich in oleic acid obtained is shown in Table 2.

Example 2
A 15% copper nitrate aqueous solution was dropped into a 9% sodium carbonate aqueous solution at room temperature to obtain a slurry. The pH after completion of the dropwise addition was 7.0. The precipitate was filtered off from this slurry, sufficiently washed with water, and then dried at 120 ° C. for 14 hours to obtain a powder. 10.43 g of this powder was suspended in water, an aqueous solution of 0.87 g of zirconium oxynitrate was added thereto and stirred at room temperature, and then water was distilled off at 70 ° C. with an evaporator. The obtained solid was dried at 120 ° C. for 14 hours and then calcined at 500 ° C. for 2 hours to obtain a catalyst (weight ratio: copper / zirconium = 100 / 5.0). A hydrogenation reaction was performed under the same conditions after the reduction activation treatment as in Example 1 except that this catalyst was used and the liquid acid 2 having the composition shown in Table 1 was used. The composition of the fatty acid rich in oleic acid obtained is shown in Table 2.

Example 3
A mixed aqueous solution of 42.82 g of copper nitrate and 1.65 g of zirconium oxynitrate was dropped into a 9% aqueous sodium carbonate solution at room temperature to obtain a slurry. The pH after the completion of dropping was 7.2. The precipitate is filtered off from this slurry, sufficiently washed with water, dried at 120 ° C. for 14 hours, and calcined at 500 ° C. for 2 hours to obtain a catalyst (weight ratio: copper / zirconium = 100 / 5.0). It was. A hydrogenation reaction was performed under the same conditions after the reduction activation treatment as in Example 1 except that this catalyst was used and the liquid acid 2 having the composition shown in Table 1 was used. The composition of the fatty acid rich in oleic acid obtained is shown in Table 2.

Example 4
A 15% copper nitrate aqueous solution was dropped into a 9% sodium carbonate aqueous solution at room temperature to obtain a slurry. The pH after completion of the dropwise addition was 7.0. The precipitate was filtered off from this slurry, sufficiently washed with water, and then dried at 120 ° C. for 14 hours to obtain a powder. 10.43 g of this powder was suspended in water, an aqueous solution of 1.27 g of yttrium nitrate was added thereto and stirred at room temperature, and then water was distilled off at 70 ° C. with an evaporator. The obtained solid was dried at 120 ° C. for 14 hours and then calcined at 500 ° C. for 2 hours to obtain a catalyst (weight ratio: copper / yttrium = 100 / 5.0). A hydrogenation reaction was performed under the same conditions after the reduction activation treatment as in Example 1 except that this catalyst was used and the liquid acid 2 having the composition shown in Table 1 was used. The composition of the fatty acid rich in oleic acid obtained is shown in Table 2.

Example 5
A 15% copper nitrate aqueous solution was dropped into a 9% sodium carbonate aqueous solution at room temperature to obtain a slurry. The pH after completion of the dropwise addition was 7.0. The precipitate was filtered from this slurry, washed thoroughly with water, and then dried at 120 ° C. for 14 hours to obtain a powder. 10.43 g of this powder was suspended in water, an aqueous solution of 0.11 g of ammonium molybdate was added thereto and stirred at room temperature, and then water was distilled off at 70 ° C. with an evaporator. The obtained solid was dried at 120 ° C. for 14 hours and then calcined at 500 ° C. for 2 hours to obtain a catalyst (weight ratio: copper / molybdenum = 100 / 1.0). A hydrogenation reaction was performed under the same conditions after the reduction activation treatment as in Example 1 except that this catalyst was used and the liquid acid 2 having the composition shown in Table 1 was used. Table 2 shows the composition of the fatty acid rich in oleic acid obtained.

Example 6
A 15% copper nitrate aqueous solution was dropped into a 9% sodium carbonate aqueous solution at room temperature to obtain a slurry. The pH after completion of the dropwise addition was 7.0. The precipitate was filtered off from this slurry, sufficiently washed with water, and then dried at 120 ° C. for 14 hours to obtain a powder. 10.43 g of this powder was suspended in water, an aqueous solution of 1.65 g of ammonium molybdate was added thereto and stirred at room temperature, and then water was distilled off at 70 ° C. with an evaporator. The obtained solid was dried at 120 ° C. for 14 hours and then calcined at 300 ° C. for 2 hours to obtain a catalyst (weight ratio: copper / molybdenum = 100/15). Using this catalyst, a hydrogenation reaction was carried out under the same conditions after the reduction activation treatment as in Example 1. The composition of the fatty acid rich in oleic acid obtained is shown in Table 2.

Example 7
A 15% copper nitrate aqueous solution was dropped into a 9% sodium carbonate aqueous solution at room temperature to obtain a slurry. The pH after completion of the dropwise addition was 7.0. The precipitate was filtered off from this slurry, sufficiently washed with water, and then dried at 120 ° C. for 14 hours to obtain a powder. 10.43 g of this powder was suspended in water, an aqueous solution of 0.55 g of ammonium molybdate was added thereto and stirred at room temperature, and then water was distilled off at 70 ° C. with an evaporator. The obtained solid was dried at 120 ° C. for 14 hours to obtain a catalyst (weight ratio: copper / molybdenum = 100 / 5.0). Using this catalyst 0.79% (vs. liquid acid), the hydrogenation reaction was carried out under the same conditions after the reduction activation treatment as in Example 1. The composition of the fatty acid rich in oleic acid obtained is shown in Table 2.

Comparative Example 1
A 15% copper nitrate aqueous solution was dropped into a 9% sodium carbonate aqueous solution at room temperature to obtain a slurry. The pH after completion of the dropwise addition was 7.0. The precipitate was filtered off from this slurry, sufficiently washed with water, dried at 120 ° C. for 14 hours, and then calcined at 500 ° C. for 2 hours to obtain a catalyst. Using this catalyst, a hydrogenation reaction was carried out under the same conditions after the reduction activation treatment as in Example 1. The composition of the fatty acid rich in oleic acid obtained is shown in Table 2.

Comparative Example 2
Using 0.40% (vs. liquid acid) of a palladium / silica alumina catalyst (produced by N.E. Chemcat Co., Ltd., palladium content 5%) in liquid acid 3 having the composition shown in Table 1, Hydrogenation was performed for 4 hours under 0.10 MPa · G hermetic conditions. The composition of the fatty acid rich in oleic acid obtained is shown in Table 2. Although the reaction rate of linoleic acid is high, it can be seen that there are very many trans isomers (elaidic acid) in oleic acid.

note)
* 1: Raw fatty acid%
* 2: Represents the weight percentage of C18: 1 trans form (elaidic acid) in all fatty acids.
* 3: C18: 2 reaction rate [%] = (C18: 2 ratio in raw fatty acid [%] − C18: 2 ratio after 4 hours of reaction [%]) / C18: 2 in raw fatty acid Ratio [%] La 100

Claims (5)

A catalyst for hydrogenation of a polyunsaturated fatty acid to a monounsaturated fatty acid, containing copper and at least one element selected from group A below.
Group A: Molybdenum, zirconium, vanadium, gallium, and elements of Group 3 of the periodic table   2. The hydrogenation catalyst according to claim 1, wherein a weight ratio of copper to a group A element (copper / group A element) is in a range of 100 / 0.1 to 100/80.   The hydrogenation catalyst according to claim 1 or 2, obtained by impregnating and supporting a metal salt of at least one element selected from Group A on a copper oxide, hydroxide, carbonate or a mixture thereof.   A method for producing a monounsaturated fatty acid, wherein a raw fatty acid containing a polyunsaturated fatty acid is hydrogenated using the hydrogenation catalyst according to claim 1. The manufacturing method of the monounsaturated fatty acid of Claim 4 which hydrogenates a raw material fatty acid after performing the reduction | restoration activation process of a catalyst in the raw material fatty acid containing a polyunsaturated fatty acid.