JPH0899036A - Catalyst for selective hydrogenation and preparation of high purity oleic acid using the same - Google Patents

Abstract

PURPOSE: To produce industrially a catalyst for selective hydrogenation comprising a highly active copper catalyst and oleic acid containing only little quantity of acid having two or more unsaturated bonds such as linoleic acid by using the catalyst. CONSTITUTION: In a method for the production of a catalyst for selective hydrogenation of acid having two or more unsaturated bonds into acid having one unsaturated bond containing metallic copper crystals the average crystal diameter of which is 30-120Å and high purity oleic acid with the use of the catalyst, high purity oleic acid is prepared by a method in which fat is hydrolyzed into the liquid aliphatic acid and glycerin, and a liquid acid which is obtained by the fractionation of the obtained aliphatic acid into the liquid acid and a solid acid is hydrogenated to prepare high purity oleic acid.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a catalyst for selective hydrogenation of polyunsaturated acids to monounsaturated acids, and a raw material for lubricants, plasticizers, oil agents, emulsifiers, detergents, etc. using this catalyst. The present invention relates to a widely used method for producing high-purity oleic acid.

[0002]

BACKGROUND OF THE INVENTION Oleic acid is generally obtained by fractionating a fatty acid obtained by hydrolyzing fats and oils such as beef tallow into a liquid acid and a solid acid, and then distilling the obtained liquid acid to complete distillation. Manufactured by acquiring a gift. However, the oleic acid produced by this method contains about 8% by weight of polyunsaturated acids such as linoleic acid, which not only reduces the purity of oleic acid, but also the hue, odor,
It is a cause of quality deterioration such as oxidation stability, and improvement has been desired from the past.

Methods for removing polyunsaturated acids such as linoleic acid in oleic acid include removal by purification of oleic acid and conversion of polyunsaturated acid to oleic acid by using a hydrogenation catalyst. As a method for purifying oleic acid, there are a urea addition method (JP-A-61-297 and JP-A-62-148449), a chromatographic separation method, and the like. The law is not always satisfactory. As a method for producing oleic acid by using a hydrogenation catalyst, a method using a fat or oil, a 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 advantage of producing extremely less saturated acid than other solid catalysts, but when fatty acids are used as raw materials,
Since copper is eluted into fatty acids and the catalyst is affected by the action, there is a disadvantage that hydrogenation activity is hardly expressed as compared with the case of using fats and oils or fatty acid esters as raw materials. Therefore, it is desired to develop a positive utilization method utilizing the advantages of the copper catalyst.

Accordingly, an object of the present invention is to industrially produce a hydrogenation catalyst comprising a highly active copper catalyst, and oleic acid containing a small amount of polyunsaturated acid such as linoleic acid using the hydrogenation catalyst. To provide a manufacturing method.

[0005]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have found that a catalyst having a size within a certain range obtained by reducing a catalyst precursor in an inert solvent. In the process of hydrogenating a liquid acid using a catalyst having metallic copper crystals, it was found that the saturated acid was generated very little and the hydrogenation activity of the polyunsaturated acid was high, and the present invention was completed.
That is, the present invention provides a catalyst for selective hydrogenation of polyunsaturated acid to monounsaturated acid, which contains metallic copper crystals having an average crystallite size of 30Å to 120Å. The present invention also hydrolyzes oils and fats into fatty acids and glycerin, and further hydrogenates the liquid acid obtained by further separating the obtained fatty acid into a liquid acid and a solid acid in the presence of a hydrogenation catalyst. In the step of producing an acid, a method for producing high-purity oleic acid, which comprises using a selective hydrogenation catalyst containing a metal copper crystal having an average crystallite size of 30Å to 120Å as a hydrogenation catalyst. It is provided.

The average crystallite diameter of the metal copper crystals used as the hydrogenation catalyst of the present invention is 30Å to 120Å, preferably 30 to 9
It is 0Å, particularly preferably 50 to 80Å. Average crystallite size
If it exceeds 120Å, there is a drawback that the activity decreases, and if it is less than 30Å, there are handling problems such as a slow filtration rate after the reaction. In the present invention, the average crystallite size of the metal copper crystals of the hydrogenation catalyst used is measured by using an X-ray diffractometer.
The X-ray diffraction line of metallic copper at the lattice spacing d = 0.209 nm was calculated and calculated from the Scherrer equation as shown in the following examples.

The hydrogenation catalyst used in the present invention may contain a metal other than metal copper crystals, or may be supported on a carrier, as long as the performance is not impaired. Specifically, a metal copper crystal catalyst supported on a carrier such as diatomaceous earth, silica, silica-alumina, alumina, niobia, activated carbon, and a promoter such as zinc oxide, barium oxide, iron oxide, manganese oxide, or lanthanum oxide were added. Examples thereof include metallic copper crystal catalysts.

The hydrogenation catalyst used in the present invention is produced, for example, by the following method. First, in the presence of a carrier component, a method in which a precipitate obtained by a coprecipitation method in which a precipitant is added to a metal salt aqueous solution containing copper that can be a catalyst component other than the carrier component is washed with water, dried, and calcined, In addition, a method of impregnating and supporting a metal salt containing copper, which may be a catalyst component other than the carrier component, from an aqueous solution state, and then drying and firing, or an oxide, hydroxide, carbonate or the like of a metal containing copper. A catalyst precursor is prepared by a method such as uniformly mixing the compounds and then firing. As the metal salt used in the precipitation method and the impregnation method, any water-soluble metal salt can be used. For example, as the metal salt of copper, sulfate, nitrate, ammonium complex salt, acetate, oxalate, acetylacetonate salt and chloride are generally used. Precipitants used in the coprecipitation method include ammonia, urea,
Examples thereof include alkaline aqueous solutions of ammonium carbonate, sodium carbonate, sodium hydrogen carbonate, sodium hydroxide, potassium hydroxide and the like. Further, when the catalyst precursor is prepared by the coprecipitation method, the adjusted pH is important, and it is desirable to carry out the adjustment at pH 2 to 13, for example. Further, in the above method, the firing temperature is preferably 300 to 600 ° C. in an oxidizing atmosphere.
To such a catalyst precursor, a trace amount component such as graphite, fatty acid salt, starch, mineral oil, talc, bentonite, or alkali metal salt is added in order not to impair the effects of the present invention in order to improve the catalyst strength. Is also good. As the catalyst precursor, a commercially available product such as a copper catalyst manufactured by Sakai Chemical Industry Co., Ltd. may be used.

The catalyst precursor for hydrogenation reaction obtained as described above is then reduced. When the catalyst precursor is reduced, 100 to 100% by a liquid phase reduction method carried out in an inert solvent such as hydrocarbons such as liquid paraffin, aliphatic alcohols such as lauryl alcohol, or fatty acid esters such as palm stearin oil. It is desirable to reduce at a temperature of 350 ° C until hydrogen absorption is no longer observed.

The catalyst for selective hydrogenation of the present invention obtained as described above is used in a method of hydrogenating a polyunsaturated acid to obtain a monounsaturated acid. In particular, a polyunsaturated acid such as linoleic acid is used. Is preferably used in a method for producing high-purity oleic acid by hydrogenating. Examples of fats and oils used in the method for producing high-purity oleic acid of the present invention include beef tallow, sheep fat, lard, palm oil, palm stearin or palm olein obtained by fractionating palm oil, high oleic safflower oil, high oleic sunflower. Oils, peanut oil, soybean oil, coconut oil, palm kernel oil and other animal and vegetable oils and fats can be mentioned. To obtain low melting point oleic acid, for example, beef tallow, sheep fat, high oleic sunflower oil, palm kernel oil and other animal and plant oils. Fats and oils are preferred.

As a method for hydrolyzing these fats and oils into fatty acids and glycerin, known methods can be used.
Specifically, it can be carried out by a generally industrially used method such as a high pressure continuous decomposition method, an intermediate pressure method, an enzyme method and the like.
The fatty acid thus obtained may be distilled by known methods and conditions, if necessary. For example, when oils and fats containing a large amount of fatty acids other than C18 fatty acids are used as the raw material and hydrolyzed, distillation is performed at this stage to obtain
By obtaining a fatty acid containing 18 fatty acids as a main component and subjecting it to the next fractionation step, the desired high-purity oleic acid can be produced more efficiently.

Next, the fatty acid thus obtained is separated into a liquid acid and a solid acid to obtain a liquid acid, and if necessary, the liquid acid is distilled. As a method of separating into a liquid acid and a solid acid, there are generally industrially used methods such as a solvent fractionation method and an activator fractionation method (for example, Japanese Patent Publication No. 32-639 and Japanese Patent Publication No. 46-35272). Can be done. The liquid acid thus obtained may be distilled by known methods and conditions, if necessary.

The liquid acid thus obtained is then hydrogenated using the hydrogenation catalyst as described above. The amount of the hydrogenation catalyst used is 0.1 to 5% by weight based on the liquid acid. The hydrogenation temperature is preferably 120 to 250 ° C, more preferably 150 to 220 ° C, and the hydrogen pressure is atmospheric pressure to 20 kg / cm ² ·.
G (G represents a gauge pressure) is preferable, and more preferably atmospheric pressure to 10 kg / cm ² · G. If the hydrogen pressure or temperature is too high, the production of saturated acid will increase, and if the temperature is too low, the catalyst activity will decrease, which is not preferable. In the hydrogenation reaction, it is preferable to hydrogenate the polyunsaturated acid content to 1 to 4% by weight, preferably 1.5 to 3% by weight, until the polyunsaturated acid content becomes less than 1% by weight. If it is added, the saturated fatty acid content increases, which is not preferable.

[0014]

The present invention will be described in more detail based on the following examples. However, the description of these examples does not limit the scope of the present invention. Incidentally, C _{n: m} in this example is
It means a fatty acid having n carbon atoms and m double bonds. Further, in the following Examples and Comparative Examples, the fatty acid composition was determined by methylating diazomethane and then performing gas chromatography analysis.

Example 1 (1) Production of copper / silica catalyst (Cu content 50% by weight) First, sodium metasilicate was neutralized with nitric acid and then washed with an aqueous sodium chloride solution to obtain silica by a known method. Next, an aqueous solution of sodium carbonate was added dropwise while keeping the aqueous solution of copper nitrate in which silica was suspended at 90 ° C. to precipitate copper oxide, followed by firing at 350 ° C. for 2 hours to prepare a catalyst precursor. The resulting catalyst precursor is in lauryl alcohol
After treatment at 200 ° C. and 25 kg / cm ² · G for 1 hour, the catalyst was filtered to convert it from an oxidation type to a reduction type. X-ray diffraction (Rigaku Denki Co., Ltd., RAD-C system unit, analysis conditions: X
An X-ray diffraction line of metallic copper was obtained by measuring with a CuK α ray as a radiation source, a voltage of 40 kV, and a current of 80 mA). The lattice spacing d = 0.209 nm
The half width (β) and the diffraction angle (θ) of the X-ray diffraction line (Fig. 1) at are calculated by the Scherrer equation (L = Kλ / β cos θ, K = 0.9
, Λ = 1.5418), and the average crystallite diameter (L) of metallic copper was calculated. For the copper / silica catalyst, β =
At 0.0245 radian, θ = 21.57 °, the average crystallite diameter of metallic copper is
It was 61Å.

(2) Method for producing oleic acid Beef tallow fatty acid obtained by hydrolyzing beef tallow under high pressure by a conventional method was fractionated by an activator method by a conventional method to obtain a liquid acid. The fatty acid composition was as shown in Table 1.

[0017]

[Table 1]

The copper / silica catalyst obtained in (1) above was added to 0.9
A hydrogenation reaction of a liquid acid having a composition as shown in Table 1 was carried out for 3 hours under the conditions of 200 ° C. and 4 kg / cm ² · G using the weight% (to the liquid acid). Then set it to bottom temperature max240
Oleic acid was obtained by simple distillation under reduced pressure of 3 mmHg at ℃. The fatty acid composition of the oleic acid was as shown in Table 2.

Comparative Example 1 The fractionated liquid acid having the composition shown in Table 1 obtained in Example 1 was treated with a copper-chromium-manganese catalyst (Sakai Chemical Industry Co., Ltd.).
(Cu content 37% by weight) (0.9% by weight (with respect to liquid acid)) and hydrogenation was carried out at 200 ° C. and 4 kg / cm ² · G for 5 hours. Obtained. The average crystallite diameter of metallic copper of the used copper-chromium-manganese catalyst was 126Å. The fatty acid composition of the obtained oleic acid is shown in Table 2.

Comparative Example 2 The fractionated liquid acid having the composition shown in Table 1 obtained in Example 1 was fractionated by X-ray diffraction, and the Raney-copper catalyst having an average crystallite diameter of 244Å metallic copper (Katayama Chemical Co., Ltd. Industry Co., Ltd.
Hydrogenation is performed for 5 hours at 200 ° C, 4 kg / cm ² · G using 0.9% by weight (made of Raney-copper-aluminum-zinc alloy developed with sodium hydroxide aqueous solution pH 12.5) (to liquid acid). Oleic acid was obtained by using the method described in Example 1 except for the above. The fatty acid composition of the obtained oleic acid is shown in Table 2.

Comparative Example 3 The fractionated liquid acid having the composition shown in Table 1 obtained in Example 1 was added with 0.4% by weight of a palladium / silica alumina catalyst (Nippon Engelhard Co., Ltd., Pd content: 5% by weight). Oleic acid was obtained by using the method described in Example 1 except that (for liquid acid) was used and hydrogenation was carried out at 50 ° C. and 1 kg / cm ² · G for 3.5 hours. The fatty acid composition of the obtained oleic acid is shown in Table 2.

Comparative Example 4 A fractionated liquid acid having the composition shown in Table 1 obtained in Example 1 was flaked with hardened beef tallow nickel / diatomaceous earth catalyst (manufactured by JGC Chemical Co., Ltd., Ni content 20% by weight). 0.2% by weight (to liquid acid) at 200 ° C and 1 kg / cm ² · G
Using the method described in Example 1 except that hydrogenation is performed for an hour,
Oleic acid was obtained. The fatty acid composition of the obtained oleic acid is shown in Table 2.

[0023]

[Table 2]

From the above results, it can be seen that Example 1 produces less saturated acid and is excellent in activity.

Example 2 Lauryl alcohol was prepared using copper oxide-barium oxide-iron oxide / diatomaceous earth (manufactured by Sakai Chemical Industry Co., Ltd., Cu content 50% by weight, Ba content 3% by weight, Fe content 1% by weight). In 200 ℃,
25kg / cm ² · G, after 1 hour treatment, filtered and average crystallite size
A catalyst having 71Å metallic copper crystals was obtained. The obtained catalyst
0.9% by weight (vs. liquid acid) was added to the liquid acid having the composition shown in Table 1 obtained by fractionation in Example 1, 200 ° C.,
Example 1 except that hydrogenation was carried out at 4 kg / cm ² · G for 2 hours.
Oleic acid was obtained using the method described. The fatty acid composition of the obtained oleic acid is shown in Table 3.

Example 3 Copper oxide-barium oxide / diatomaceous earth (Sakai Chemical Industry Co., Ltd.)
(Cu content 50% by weight, Ba content 3% by weight) in lauryl alcohol at 200 ° C., 25 kg / cm ² · G for 1 hour, and then filtered to obtain metallic copper crystals with an average crystallite diameter of 58Å. A catalyst having was obtained. 0.9 wt% of the obtained catalyst (vs. liquid acid) was added to the liquid acid having the composition shown in Table 1 obtained by fractionation in Example 1, and hydrogenation was carried out at 200 ° C. and 4 kg / cm ² · G for 1 hour. Oleic acid was obtained using the method described in Example 1 except for the above. The fatty acid composition of the obtained oleic acid is shown in Table 3.

Example 4 The same copper oxide-barium oxide / diatomaceous earth catalyst as in Example 3 was treated in palm stearin oil at 130 ° C., atmospheric pressure and 1000 liters / hr · kg-catalyst after hydrogen treatment for 8 hours. After filtration, a catalyst having metal copper crystals with an average crystallite diameter of 62Å was obtained.
0.9% by weight of the catalyst (relative to liquid acid) was added to the liquid acid having the composition shown in Table 1 obtained by fractionation in Example 1,
Oleic acid was obtained by the method described in Example 1 except that hydrogenation was carried out at 200 ° C. and 4 kg / cm ² · G for 1 hour. The fatty acid composition of the obtained oleic acid is shown in Table 3.

Example 5 The same copper oxide-barium oxide / diatomaceous earth catalyst as in Example 3 was used in palm stearin oil at 120 ° C., 5 kg / cm ² · G,
The catalyst was treated for 12 hours under a hydrogen flow of 200 liters / hr · kg-catalyst and then filtered to obtain a catalyst having metallic copper crystals having an average crystallite size of 93Å. 0.9% by weight of the catalyst (vs liquid acid) was used in Example 1.
Oleic acid was obtained by the method described in Example 1 except that hydrogenation was carried out at 200 ° C. and 4 kg / cm ² · G for 3.5 hours in addition to the liquid acid having the composition shown in Table 1 obtained by fractionation in Example 1. The fatty acid composition of the obtained oleic acid is shown in Table 3.

Comparative Example 5 The same copper oxide-barium oxide / diatomaceous earth catalyst as in Example 3 was used as is, without pre-reduction, and the catalyst
0.9% by weight (vs. liquid acid) was added to the liquid acid having the composition shown in Table 1 obtained by fractionation in Example 1, 200 ° C.,
Example 1 except that hydrogenation was carried out at 4 kg / cm ² · G for 5 hours.
Oleic acid was obtained using the method described. The fatty acid composition of the obtained oleic acid is shown in Table 3.

[0030]

[Table 3]

[Brief description of drawings]

FIG. 1 d = 0.209 of metallic copper of the catalyst used in Example 1.
The X-ray diffraction line in nm is shown.

Claims (6)

[Claims] 1. A catalyst for selective hydrogenation of polyunsaturated acids to monounsaturated acids, which comprises metallic copper crystals having an average crystallite size of 30Å to 120Å. 2. The catalyst for selective hydrogenation according to claim 1, which is obtained by reducing a catalyst precursor in an inert solvent. 3. The catalyst for selective hydrogenation according to claim 1, wherein the monounsaturated acid is oleic acid. 4. A liquid acid obtained by hydrolyzing fats and oils into fatty acids and glycerin and further fractionating the obtained fatty acids into liquid acids and solid acids is hydrogenated in the presence of a hydrogenation catalyst to obtain olein. A method for producing high-purity oleic acid, which comprises using the selective hydrogenation catalyst according to claim 1 as a hydrogenation catalyst in the step of producing an acid. 5. The method for producing high-purity oleic acid according to claim 4, wherein the hydrogenation catalyst is used in an amount of 0.1 to 5% by weight based on the liquid acid. 6. The method for producing high-purity oleic acid according to claim 4, wherein the selective hydrogenation catalyst according to claim 2 is used.