JP2008231430A - Device for producing fatty acid ester - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently produce a fatty acid ester at a high reaction rate under a mild condition in the transesterification reaction using an ion exchange resin which can cut a step for separating a catalyst which is the defect of a uniform phase alkali catalyst. <P>SOLUTION: A device for producing the fatty acid ester has an introducing port of a mixture of oils and fats and alcohols on one side of a column filled with an anion exchanger and a recovering port of the fatty acid ester produced on the other side of a column, in which reaction temperature is 10-70°C. The amount of the produced fatty acid ester based on the unit weight of an ion exchange resin and on the time is large because the device uses oils and fats at a high concentration. That is to say, the productivity of the fatty acid ester is large. The device contributes to a reduction in the environmental load by utilizing the resultant fatty acid ester in a biodiesel fuel. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a fatty acid ester. More specifically, the present invention relates to a method for producing a fatty acid ester by an ester exchange method using an anion exchanger using fats and oils as a raw material.

Fatty acid esters synthesized by transesterification of fats and alcohols have attracted attention as biodiesel fuels. Compared to conventional petroleum-based diesel fuel (via), biodiesel fuel
(1) The exhaust gas when burned is about 75% clean.
(2) Reduction of carbon monoxide, hydrocarbons, particulate matter, etc. by 10-20%.
(3) The exhaust gas does not contain sulfur oxides or sulfates.
(4) It has many characteristics such as high lubrication performance.

  This fuel has the advantage that it can be used as it is without modification to any diesel engine. Moreover, since waste edible oil that contributes to environmental pollution can also be used as a raw material, it is a biomass raw material that can double the environmental burden. In the United States and Europe, we have already started using petroleum diesel fuel mixed with about 1-20% biodiesel fuel, which alone reduces the load on the engine due to its high lubricity and is environmentally friendly. It has been reported that the burden on health and health has also been reduced. In this way, the movement to actively use biodiesel fuel, which is superior to petroleum diesel fuel in all respects, has been gradually increasing in recent years, but at a cost two to three times that of petroleum diesel fuel. There is a big problem. This is because the current biodiesel fuel production process uses a phase-homogeneous alkali catalyst such as potassium hydroxide, which adds to the cost of separating and removing these catalysts during commercialization. There is an urgent need to search for highly active heterogeneous solid catalysts that do not require a separation process.

A method using a complex oxide having a perovskite structure such as CaTiO ₃ and CaMnO ₃ as a heterogeneous solid catalyst for the direct production of biodiesel fuel (see Patent Document 1), A method using an alkaline earth metal oxide, hydroxide or carbonate in a subcritical state (see Patent Document 2), a method using quick lime or bituminous lime (see Patent Document 3), calcium hydroxide or calcium oxide There is known a method using the method (see Patent Document 4). However, these methods have problems such as high temperature required, difficulty in regeneration of the catalyst, expensive catalyst, and insufficient reaction rate.

  On the other hand, apart from the production of biodiesel fuel, a method for producing a fatty acid ester from triglyceride and alcohol has been known for a long time. For example, a method of adding alcohols to triglyceride and, if necessary, a solvent and bringing it into contact with a basic ion exchange resin (anion exchange resin) (see Patent Document 5) can be mentioned. However, in this method, the triglyceride serving as a substrate is preferably diluted with respect to alcohol. This can be done by 1) shifting the equilibrium of the transesterification reaction to the product side to increase the equilibrium reaction rate, 2) avoiding damage due to resin swelling in the packed bed reactor, and 3) lowering the molar ratio of alcohol. This is considered to be due to the viewpoint of preventing phase separation caused by insoluble triglyceride caused by the above. As a result, a large amount of alcohol is used in contact with the ion exchange resin, the target fatty acid ester cannot be obtained at a high concentration, and the production amount of the fatty acid ester per ion exchange resin is not sufficient. There was a problem.

  In addition, a method is known in which triglyceride and alcohol are reacted in the presence of a solid acid catalyst such as a composite metal compound, metal sulfate, heteropolyacid, synthetic zeolite, or ion exchange resin (see Patent Document 6). However, although the method of patent document 6 has the advantage that there is little by-product of fatty acid soap, without pre-processing the free fatty acid in fats and oils, reaction rate is small and is not practical. In addition, since the ion exchange resin here functions as a solid acid catalyst, the usable resin is naturally limited to the cation exchange resin.

JP 2002-294277 A JP 2002-308825 A JP 2004-35873 A JP 2001-271090 A JP-A-62-218495 JP-A-6-313188

  An object of the present invention is to efficiently produce a fatty acid ester at a high reaction rate under mild conditions in an ester exchange reaction using an ion exchange resin that can cut the catalyst separation step, which is a drawback of a homogeneous alkali catalyst. is there.

  The gist of the present invention is a method for producing a fatty acid ester by a transesterification reaction between an oil and fat and an alcohol, using an anion exchanger as a catalyst, and a molar ratio of the oil and fat to the alcohol is 1/30 to 1 / 1 in the method for producing a fatty acid ester.

  Another aspect of the present invention is the above fatty acid ester, wherein the fats and oils are natural fats and oils, synthetic fats and oils, synthetic triglycerides, synthetic triglycerides containing monoglycerides and / or diglycerides, modified products thereof, or waste oils and fats containing them. Exist in the manufacturing method.

  Furthermore, the other summary of this invention exists in the manufacturing method of the said fatty acid ester whose alcohol is a C1-C5 lower alcohol.

  Furthermore, the other summary of this invention exists in the manufacturing method of the said fatty acid ester whose anion exchanger is a strongly basic porous anion exchange resin.

  Furthermore, another gist of the present invention resides in the above-mentioned method for producing a fatty acid ester, wherein the transesterification reaction is carried out using an expanded bed column type reactor.

(1) The catalyst separation step, which is a drawback of the soaking alkali catalyst, can be cut.
(2) The production amount of fatty acid ester per ion exchange resin to be used is large.
(3) The amount of fatty acid ester produced per hour is large.
(4) Productivity is high because fats and oils are used at a high concentration.
(5) Ion exchange resins are generally less expensive than complex metal oxides and have stable catalytic activity.
(6) Even when the performance of the ion exchange resin deteriorates, the exchange group can be easily regenerated.
(7) When an expanded bed column type reactor is used, damage of the resin due to swelling can be avoided.
(8) The use of fatty acid esters as biodiesel fuel can contribute to the reduction of environmental load.

[1] Anion exchanger Examples of the anion exchanger include anion exchange resins and anion exchange membranes, and anion exchange resins are preferred. Examples of the anion exchange resin include strong base anion exchange resins and weak base anion exchange resins, and strong base anion exchange resins are preferred. When the anion exchange resin is classified according to the degree of crosslinking or porosity, a gel type, a porous type, a high porous type and the like can be mentioned, and a porous type and a high porous type are preferable.

  Examples of commercially available products include Diaion PA-306 (Mitsubishi Chemical Co., Ltd.), Diaion PA-306S (same), Diaion PA-308 (same), Diaion HPA-25 (same) Dowex 1-X2 (Made by Dow Chemical Company), Amberlite IRA-45 (made by Organo), Amberlite IRA-94 (same), etc. can be used.

Since a commercial product of an anion exchange resin is Cl type at the time of purchase, it is used in the present invention after being substituted with an OH group. For example, a 0.5 to 2 mol / dm ³ aqueous NaOH solution is used as the displacing agent, and the flow rate of the displacing agent is preferably about 2 to 10 ml-NaOH / min per 1 ml of anion exchange resin. The flow rate is 5 to 20 ml per 1 ml of anion exchange resin. After the substitution is completed, the resin is taken out from the column and thoroughly washed with distilled water so that the substitution agent does not remain. The pH of the resin cleaning solution is measured to confirm that it has the same pH as that of distilled water, and finally washed with a predetermined alcohol and used in the present invention.

  In the case of a stirred tank reactor, the amount of the anion exchange resin used is usually selected from the range of 100 to 1000 g, preferably 200 to 800 g, per mole of fats and oils. After use, it can be used repeatedly for the same reaction, but it is preferable to regenerate the resin as appropriate. When ion exchange resin is used as a packed bed, the amount of oil / fat per liter of resin used is usually 10 to 100 mL, preferably about 15 to 60 mL, and then regenerated according to known methods. . For example, it is treated with an acid aqueous solution and washed with water or alcohol. Washing with an aqueous acid solution is necessary to desorb free fatty acids produced by the hydrolysis reaction that occurs in equilibrium with the transesterification reaction from the resin. As such an acid, organic acids such as formic acid, acetic acid and citric acid can be used.

[2] Reaction substrate [2-1] Oils and fats:
The fats and oils used in the present invention are not particularly limited, and may be natural fats and oils, synthetic fats and oils, or a mixture thereof. For example, soybean oil, palm oil, palm oil, palm kernel oil, corn oil, peanut oil, sunflower oil, olive oil, safflower oil, coconut oil, oak oil, almond oil, black walnut oil, apricot oil, cocoa butter oil , Dairy oil, safflower oil, cinnamon oil, linseed oil, cottonseed oil, rapeseed oil, giraffe oil, castor oil, cottonseed stearin, sesame oil and other vegetable oils, lard oil, chicken oil, butter oil, cod liver oil, deer oil , Animal oils such as dolphin oil, sardine oil, mackerel oil, horse fat, pork fat, bone oil, sheep oil, cow leg oil, murine dolphin oil, shark oil, sperm whale oil, whale oil, beef fat, cow bone fat, Examples include vegetable oils discarded from restaurants, food factories, general households, and the like. Oils and fats containing these oils alone or mixed, oils and fats containing diglycerides and monoglycerides, synthesized triglycerides, synthetic triglycerides containing monoglycerides and / or diglycerides, and some of these oils and fats are modified by oxidation, reduction, etc. Modified oils and fats may be used. Or the fats and oils processed product which has these fats and oils as a main component can also be used as a raw material.

  In fats and oils, components other than fats and oils may be mixed. Specifically, crude oil, heavy oil, light oil, mineral oil, essential oil, coal, fatty acid, sugar, metal powder, metal salt, protein, amino acid, hydrocarbon, cholesterol, flavor, pigment compound, enzyme, perfume, alcohol, fiber, Resins, rubbers, paints, cements, detergents, aromatic compounds, aliphatic compounds, soot, glass, earth and sand, nitrogen-containing compounds, sulfur-containing compounds, phosphorus-containing compounds, halogen-containing compounds, etc., but are not limited thereto. . These foreign matter components are preferably applied to the present invention after being removed by sedimentation, filtration, liquid separation or the like.

[2-2] Alcohols:
The alcohols used in the present invention are not particularly limited, and examples thereof include alcohols having a saturated linear or branched hydrocarbon skeleton having 1 to 8 carbon atoms, preferably 1 to 5 carbon atoms. For example, methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, n-butyl alcohol, t-butyl alcohol and the like can be mentioned. These alcohols can be used alone or in admixture of two or more. In the present invention, it is preferable to use methanol and / or ethanol from the viewpoint of availability and availability of the obtained fatty acid ester. In the present invention, alcohols act as a reaction substrate for the alcoholysis of fats and oils (transesterification reaction), and also have a solvent action for adjusting the dilution and viscosity of fats and oils.

[2-3] Molar ratio of fats and oils:
One of the most important requirements in the present invention is the molar ratio of fats and alcohols used as reaction substrates. It is essential that the molar ratio of fats and oils to alcohol is 1/30 to 1/1, preferably 1/20 to 1/2, more preferably 1/15 to 1/3, particularly preferably. Is in the range of 1/10 to 1/3. When this is expressed in terms of the molar concentration of fats and oils, it is in the range of 3.2 to 50 mol%, preferably 4.8 to 33 mol%, more preferably 6.2 to 25 mol%, particularly preferably 9 to 25 mol%. It becomes. When the amount of fats and oils is too large, the amount of alcohol becomes relatively small, and as a result, the volume of the reaction product is remarkably reduced. On the other hand, even if there are too few fats and oils, the equilibrium reaction does not proceed to the alcohololysis side, and a single phase of fats and oils that do not dissolve in alcohols may be generated, resulting in a two-layer system. I can't get it. The fats and alcohols preferably form a homogeneous phase as a mixture of both.

  In a model case where triolein (oleic acid triglyceride: molecular weight 879) is selected as the fat and oil and ethanol (molecular weight 46) is selected as the alcohol, the molar ratio of the fat and alcohol to the range of 1/30 to 1/1 is When expressed in terms of% by weight, it is 38.9 to 95.0% by weight, so it can be seen that the molar ratio of fats and alcohols in the present invention is significantly high as the fats and oils concentration. This is in contrast to the fact that in the invention of Patent Document 5 cited above, a dilute solution having a triglyceride concentration of 0.1 to 20%, preferably 0.1 to 3% is desirable.

[2] Other reaction conditions and post-treatment (1) The reaction temperature is about 10 to 100 ° C, preferably 10 to 70 ° C. Most preferred is a mild reaction near room temperature. When the above range is exceeded, there is a problem with the heat resistance of the ion exchanger, and the product may be colored. On the other hand, if it is less than the above, the reaction rate is small and there is a problem in productivity. Although the reaction time (contact time) depends on the reaction temperature and the amount of ion-exchange resin used, it is preferable to set the reaction rate of fats and oils so as to reach the equilibrium reaction rate. For example, the reaction is performed at a reaction temperature of 50 ° C., usually 1 to 10 hours, preferably 3 to 5 hours in the stirring layer, and 5 minutes to 2 hours, preferably 10 minutes to 1 hour in the flow system. The equilibrium reaction rate is not necessarily 100%, and varies depending on the molar ratio. More specifically, when 4 g (wet weight) of the ion exchange resin is used in the stirring tank, the total reaction liquid amount is 10 g, and the reaction temperature is 50 ° C., the molar ratio is 1/3 for about 3 hours, and the molar ratio 1 / In the range of 6 to 1/10, both reach the equilibrium reaction rate in about 1.5 hours.

(2) The reaction pressure is not particularly limited. Although it is easy to operate under normal pressure, the pressure may be increased to about 1 to 10 atm if necessary.

(3) A reaction solvent is not particularly required. This is because alcohols used as a reaction substrate also serve as a solvent. However, benzene, xylene, toluene, tetrahydrofuran, dioxane, for the purpose of adjusting viscosity and liquid permeability, such as when passing through an ion exchange resin layer packed in a column with both reaction substrates consisting of a mixture of fats and alcohols, Dimethylformamide, acetone, diethyl ether and the like may be mixed as appropriate.

(4) The contact method between the mixture of fats and oils and alcohol and the ion exchange resin is not particularly limited, such as a batch method or a continuous method. Examples thereof include a method using a stirring tank, a method of passing through a packed bed, a method using a fluidized bed reactor, a shaking reactor, and the like. When an ion exchange resin is packed in a column and used, an embodiment using an expanded bed column packed layer having a high porosity is preferable in order to prevent the resin from swelling and being damaged. Here, the expanded bed column is a separation / purification method in which the target component dissolved in a fluid with a high viscosity or a solid content is adsorbed and recovered by adsorbent particles, and the inside of the column faces upward. The column is subjected to column chromatography operation in a state where the adsorbent particles having a large specific gravity are suspended in a stationary state and the porosity is kept large. 2001) Known methods described in pages 145-148 and the like can be used. In the range where the molar ratio of fats and oils to alcohols is large, the problem of breakage of the ion exchange resin due to swelling tends to occur, so care is taken in designing the reactor.

(5) Post-treatment (separation, purification, regeneration of ion exchange resin, etc.)
In the case of using a stirred tank reactor, after cooling to a predetermined temperature and separating the resin as the solid phase, the liquid phase is separated into a fatty acid ester layer and a glycerin layer. Centrifugation can also be used. If necessary, the fatty acid ester layer is subjected to water washing, alkali washing, adsorbent treatment, etc., and further alcohol is removed to produce a product. As the adsorbent, activated carbon, acid clay, diatomaceous earth, or the like can be used. On the other hand, a glycerol layer is isolate | separated by specific gravity difference, and glycerol is collect | recovered by a well-known method.

  EXAMPLES Hereinafter, although an Example is given and the structure and effect of this invention are demonstrated concretely, this invention is not restrict | limited at all by the following Example, unless it deviates from the summary.

  In Examples, unless otherwise specified, OH form was used for anion exchange resin and H form for cation exchange resin, and these were washed with distilled water and ethanol in this order before being subjected to the reaction. Table 1 summarizes the basic physical property values of the ion exchange resins used in Examples and Comparative Examples.

[Example 1]
Triolein (manufactured by Sigma Aldrich, purity 99%), which is a synthetic triglyceride, was used as fats and oils, and ethanol (manufactured by Wako Pure Chemical Industries, Ltd., special grade) was used as alcohols. 10.0 g of a solution prepared so that the molar ratio between them (triolein / ethanol) was 1/10 was collected in a 500 mL wide-mouthed medium bottle, and a porous anion exchange resin (manufactured by Mitsubishi Chemical Corporation, Diaion PA306S) was charged in a wet weight of 4.0 g. Then, it was shaken at a speed of 150 spm in a 50 ° C. constant temperature bath. As a result of analyzing the solution after 3 hours from the start of the reaction by high performance liquid chromatography (HPLC), the amount of ethyl oleate produced was 19.3 mmol. This catalyst had a very excellent activity of 1.60 (mmol / g-Catalyst · hr) for the ethyl oleate production reaction. The results are shown in Table 2.

  The HPLC was performed by a gradient method (column temperature 40 ° C., output wavelength 205 nm) using acetonitrile, 2-propanol and ultrapure water as an eluent.

[Example 2]
A production reaction of ethyl oleate was carried out in the same manner as in Example 1 except that a porous anion exchange resin (Diaion PA308, manufactured by Mitsubishi Chemical Corporation) was used as a catalyst. As a result, the production amount of ethyl oleate was 16.6 mmol. This catalyst had a very excellent activity of 1.38 (mmol / g-Catalyst · hr) for the reaction for producing ethyl oleate. The results are shown in Table 2.

[Example 3]
A production reaction of ethyl oleate was carried out in the same manner as in Example 1 except that a high-porous anion exchange resin (Diaion HPA25, manufactured by Mitsubishi Chemical Corporation) was used as a catalyst. As a result, the production amount of ethyl oleate was 14.7 mmol. This catalyst had a very excellent activity of 1.23 (mmol / g-Catalyst · hr) for the reaction for producing ethyl oleate. The results are shown in Table 2.

[Comparative Example 1]
A porous cation exchange resin (Diaion PK208, manufactured by Mitsubishi Chemical Corporation) was used as a catalyst, and an ethyl oleate formation reaction was performed in the same manner as in Example 1 except that the reaction time was 5 hours. As a result, the amount of ethyl oleate produced was 1.0 mmol. The activity of this catalyst with respect to the ethyl oleate production reaction was 0.05 (mmol / g-Catalyst · hr). The results are shown in Table 3.

[Example 4]
A column with a water jacket having an inner diameter of 11 mm and a length of 300 mm was set up vertically, and hot water was circulated to keep the internal temperature at 50 ° C. In this column, a porous anion exchange resin (Made by Mitsubishi Chemical, Diaion PA306S) was packed in advance in a wet weight of 7.0 g. Subsequently, using a peristaltic pump, a solution of triolein (Sigma-Aldrich, purity 58%) and ethanol in a molar ratio (triolein / ethanol) 1/10 (50 ° C.) was continuously supplied from the bottom of the column at a constant flow rate. Supplied to. The reaction reached a steady state with a residence time of about 20 minutes. At this time, the liquid was recovered from the upper part of the column, and the liquid composition was analyzed by HPLC. As a result, the concentration of ethyl oleate in the liquid was about 0.8 mol / L.

[Example 5]
A production reaction of ethyl oleate was carried out in the same manner as in Example 1 except that the molar ratio of triolein to ethanol (triolein / ethanol) was adjusted to 1/6. The amount of ethyl oleate produced after 3 hours from the start of the reaction was 22.6 mmol. This catalyst had a very excellent activity of 2.02 (mmol / g-Catalyst · hr) for the reaction for producing ethyl oleate. The results are shown in Table 2.

[Example 6]
A production reaction of ethyl oleate was carried out in the same manner as in Example 1 except that the molar ratio of triolein to ethanol (triolein / ethanol) was adjusted to 1/3. As a result, the amount of ethyl oleate produced was 20.5 mmol. This catalyst had a very excellent activity of 1.85 (mmol / g-Catalyst · hr) for the reaction for producing ethyl oleate. The results are shown in Table 2.

[Comparative Example 2]
50 g of a solution prepared so that the molar ratio of triolein to ethanol (triolein / ethanol) was 1/1527 (a dilute solution having a fat concentration of 1.2% by weight) was collected, and a porous anion exchange resin (as a catalyst) The production reaction of ethyl oleate was carried out in the same manner as in Example 1 except that 6.5 g of Diaion PA308) manufactured by Mitsubishi Chemical Corporation was added and the reaction time was 2 hours. As a result, the amount of ethyl oleate produced was 1.90 mmol. This catalyst was 0.06 (mmol / g-Catalyst · hr) for the ethyl oleate formation reaction. The results are shown in Table 3.

  In Comparative Example 2, when the fat and oil concentration is lowered and the alcohol is greatly excessive, the equilibrium is shifted to the product side, but the substrate content in the reaction solution is lowered, so that the amount of ethyl oleate produced is reduced and the production is reduced. It is inferior in nature.

  The fatty acid ester which is the target product of the present invention can be used as a biodiesel fuel with a small environmental load. It can be used as it is, or appropriately mixed with light oil or the like.

Claims (5)

One of the columns filled with the anion exchanger has an inlet for the mixture of fats and oils and a recovery port for the fatty acid ester formed on the other, and the reaction temperature is 10 to 70 ° C. Fatty acid ester production equipment. 2. The fatty acid ester production apparatus according to claim 1, further comprising an inlet for the mixture of the fats and oils and the alcohol at the bottom of the column and a recovery port for the fatty acid ester at the top of the column.   The apparatus for producing a fatty acid ester according to claim 1 or 2, wherein the reaction pressure is normal pressure. An apparatus for producing a fatty acid ester, comprising an inlet for a mixture of fats and oils and a recovery port for a fatty acid ester produced at the top at the bottom of a column filled with an anion exchanger. The apparatus for producing fatty acid esters according to claim 1, wherein an expanded bed column type reactor is used for the column.