JPH02180996A - Continuous method and apparatus of urea addition and separation - Google Patents

Abstract

PURPOSE:To separate an oil such as fatty acid (deriv.) or a hydrocarbon oil into two components, one which forms a urea adduct and the other which does not form any adduct, with a simple apparatus without using solid-liquid separation process and without producing waste water by subjecting a urea adduct of an oil component formed by reacting a raw material oil with urea in a solvent to a specific treatment. CONSTITUTION:A raw material oil (e.g. ethyl ester of sardine oil) is reacted with urea in an org. solvent (e.g. methanol) to form a urea adduct of an oil (e.g. a lowly unsatd. ethyl ester). From the reaction mixture an unadded component chiefly comprising an unreacted oil (e.g. a highly unsatd. ethyl ester) is separated by extraction with an extractant (e.g. n-hexane), and the urea adduct in the extraction residue is heated to decompose. The oil produced by the decomposition is separated by extraction with an extractant (e.g. n-hexane). Urea and the solvent remaining in the extraction residue are recycled and reused.

Description

[Detailed Description of the Invention] [Industrial Application Field] ■ The present invention is a method for separating compositions consisting of fatty acids or their derivatives and oil components such as hydrocarbons into components that generate urea adducts and components that do not. Regarding the method and the equipment used therefor.

[Conventional technology]

Generally speaking, oils include mineral oils such as hydrocarbons;
Vegetable oils; synthetic oils, etc. Since these oils usually exist as a mixture of various components, it is necessary to separate them into each component in order to obtain oils with properties appropriate to the intended use or to obtain components with useful physiological activity. For example, highly unsaturated fatty acid components in animal and vegetable oils, especially fish oils, have useful physiological activities, and it is important to separate and concentrate them. Furthermore, in the field of petroleum industry, it is necessary to separate straight chain hydrocarbons from branched chain or alicyclic hydrocarbons in order to obtain oils with properties appropriate to the intended use.

A urea addition fractionation method is known that utilizes the property that only one of these components reacts with urea to produce a urea adduct. Specifically, the following methods are known as such urea addition fractionation methods.

■ Compositions consisting of fatty acids or their derivatives (hereinafter referred to as “
A urea adduct is produced by stirring and mixing the urea methanol solution and the fatty acid composition and cooling the mixture. The precipitated urea adduct is filtered off, the methanol in the filtrate is distilled off, and the residue is washed with water or extracted with a solvent to obtain highly unsaturated components. In addition, hot water is added to the urea adduct to decompose it to obtain a low degree unsaturated component as a floating oil component.

■ 5 to 8 carbon atoms containing 20% by volume or less of methanol
The fatty acid composition and solid urea are stirred and mixed in a hydrocarbon solvent to react. After the reaction, the urea adduct is filtered off, and the filtrate is subjected to membrane solvent under reduced pressure to obtain highly unsaturated components. Further, a solvent having the above composition is added to the urea adduct and heated to 70 to 120°C to decompose it, solid urea is filtered off, and the filtrate is subjected to a membrane solvent under reduced pressure to obtain a low unsaturated component.

Solid urea is used repeatedly (Special Publication No. 6340239)
.

■ Raw petroleum is stirred and mixed with a urea aqueous solution together with a solvent such as methylene chloride to react. After the reaction, the urea adduct is filtered off, and the filtrate is desolvented to obtain a low melting point oil (dewaxed oil). If necessary, water is added to the urea adduct and it is decomposed by heating to obtain a high melting point oil (paraffin) as a floating oil component.

[Problem to be solved by the invention]

Since all of the above-mentioned fractionation methods include a filtration step, they have the following problems. That is, first, the device becomes complicated.

Furthermore, since the urea adduct is in the form of fine crystals and filtrate components adhere to it, complete recovery is difficult unless a large amount of cleaning solvent is used. Furthermore, in order to make these conventional methods continuous, it is essential to transfer the solid, so it is necessary to use equipment? ^ must be an open system, which is particularly unfavorable for substances that are easily oxidized by oxygen in the air, such as highly unsaturated fatty acids.

In addition, each of the above separation methods has the following problems.

That is, in method (2), since the filtrate contains a considerable amount of urea in addition to oil, when methanol is distilled off when recovering the oil in the filtrate, a urea adduct of a highly unsaturated component is produced. If this is removed by filtration, the urea adduct will be greatly reduced, so hot water is usually added to decompose the urea adduct, but emulsification tends to occur at this time, and loss of oil content is unavoidable. In addition, urea-rich wastewater is produced. The same is true when recovering less unsaturated components from urea adducts, and a considerable amount is lost in wastewater. In addition, in order to recover large urea that has formed a urea adduct, it is necessary to distill off water, which is expensive, so the current situation is that it is not reused and is discarded as is. That is, the disadvantages are that the yield is poor, it is difficult to reuse urea, and multiple wastewaters are produced.

In method (2), since the reaction site is limited to the solid urea surface, the reactivity is low and the reaction takes a long time. In addition, solid urea is an unsaturated component having 2 to 4 double bonds (for example, 18:
2.18:3.18:4.20:2.20:3.20:
4, etc.), so it is difficult to form adducts with 20:5.22:
It is impossible to highly concentrate highly unsaturated components having 5 or more double bonds, such as 6. Furthermore, since a high temperature of 80° C. or higher is required to decompose the urea adduct, deterioration of the fatty acid or its derivative is likely to occur.

In method (2), since urea does not dissolve in the organic layer, the reaction is limited to the interface between the organic layer and the urea aqueous solution, and therefore the reactivity is low. Therefore, like the above method (1), the reaction takes a long time, and it is difficult to obtain an oil with an extremely low melting point.

That is, the conventional urea addition fractionation method for oil has the following problems, and it has been eagerly awaited to develop a urea addition fractionation method for oil that solves these problems.

(i) A filtration (solid-liquid separation) step is required, and there are various problems associated with this step.

(ii) It is difficult to reuse urea.

(iii) Wastewater is generated.

(iv) Since the reactivity is low, the reaction takes a long time and it is difficult to classify the intensity.

(v) Decomposition of urea adducts requires relatively high temperatures and tends to cause deterioration of highly unsaturated components).

[Means to solve the problem]

In view of these circumstances, the present inventors have made extensive studies to solve the problem that we had previously discussed, and have found that if the unreacted oil is extracted using an extraction solvent without filtering out the urea adduct, urea, The present invention was completed by discovering that both reaction solvents can be reused and that oil fractionation can be performed continuously with a simple device at high AH degrees.

That is, in the present invention, raw oil and urea are reacted in a reaction solvent to produce a urea adduct of oil, and unreacted oil is extracted and dissolved from the reaction mixture, and the urea adduct in the reaction mixture is extracted. The present invention provides a continuous urea addition fractionation method for oil components, which is characterized in that the oil components are decomposed by heat treatment, the decomposed oil components are extracted with a solvent, and the remaining urea and reaction solvent are reused.

The present invention also provides a reaction tank 11 for reacting raw oil and urea in a reaction solvent, an extractor 2 for extracting unreacted oil from the reaction mixture with an extraction solvent, and a heating device 3 for decomposing urea adducts. The present invention also provides a continuous urea addition and fractionation apparatus for oil components, which is characterized by being equipped with an extractor 4 for extracting the decomposed oil components using an extraction solvent.

The method of the present invention will be described below with reference to drawings showing an example of the apparatus of the present invention.

In the method of the present invention, first, in the reaction tank 1, raw material oil and urea are reacted in a reaction solvent to produce a urea adduct of oil. The raw material oil used in the present invention is a mixed composition containing components that form adducts with urea and components that do not. Specific examples include various young vegetable oils including marine animal oils such as fish oil and cod liver oil. or derivatives thereof (fatty acids, fatty acid esters, glycerides, fatty alcohols, waxes, soaps, etc.), or artificially converted oils and fats or mixtures thereof, petroleum hydrocarbons, etc., among which fatty acids, Preferred are fatty acid T-alkyl esters, aliphatic alcohols, glycerides, and hydrocarbons.

In the present invention, the reaction solvent is, for example, a carbon number of 1 to 3.
lower alcohols, mixtures of these alcohols and water, or water, among which methanol is particularly preferred.

The reaction is preferably carried out by first adding urea to a reaction solvent to create a reaction solvent solution of urea, and then adding the raw oil to this. The reaction solvent solution of urea is usually 3
Prepared at 0-65°C. However, urea does not need to be completely dissolved in this solution. After adding raw oil,
Urea adducts are produced and become slurry-like, but if the liquid temperature is lowered as necessary, the amount of urea adducts produced can be increased.

The urea adduct formed here is, for example, an adduct of a low unsaturated fatty acid ester and urea when a fatty acid ester composition is used as a raw material oil, and a direct adduct when a petroleum hydrocarbon is used as a raw material oil. It is an adduct of quenched hydrocarbon and urea. On the other hand, highly unsaturated fatty acid esters in the fatty acid ester composition and branched or alicyclic hydrocarbons in petroleum hydrocarbons exist in the reaction mixture as unreacted oil components.

Unreacted oil (non-added components) is transferred to extractor 2 and extracted from the reaction mixture with an extraction solvent. As the extractor, for example, a countercurrent distribution type continuous extractor, a combination of a mixer and a continuous centrifugal separator, etc. are suitably used. The extraction solvent used here is a solvent that is immiscible with the reaction solvent, such as an aliphatic hydrocarbon or alicyclic hydrocarbon having 5 to 8 carbon atoms.

The extracted unreacted oil is separated from the extraction solvent by removing the solvent under reduced pressure using, for example, a solvent distillation column 5. The extraction solvent recovered here can be reused.

On the other hand, the reaction solvent containing the urea adduct, which is the extraction residue, is decomposed into urea and oil (additional component) by heating in the heating bag @3. A heating temperature of 30 to 65°C is sufficient.

The decomposed oil (additional components) is extracted in the extractor 4 using an extraction solvent similar to the above-mentioned extraction solvent. As the extractor 4, one similar to the above-mentioned extractor 3 can be used. Further, the extracted additional components are separated from the extraction solvent by removing the solvent under reduced pressure using a solvent distillation column 6, for example. The extraction solvent recovered here can be reused.

A solution of urea in the reaction solvent is obtained as the extraction residue, which can be directly reused. Therefore, the raw material oil can be added again to this solution, and the same operations as described above can be carried out.

[Action and effect of the invention]

The process of the present invention does not include a solid-liquid separation process such as filtration, so the equipment is simple, and the entire equipment can be easily sealed, so it is possible to remove substances that are easily oxidized by air, such as highly unsaturated fatty acids. It is very convenient for handling. In addition, the reaction solvent, extraction solvent, and urea can all be used repeatedly without loss. Furthermore, no waste water is generated3, and the temperature required to decompose the urea adduct is usually around 50°C, which is relatively low, which is advantageous for handling highly unsaturated fatty acids. In addition, the strength of the reaction (degree of fractionation) can be easily adjusted by appropriately changing the ratio of amounts of the raw material oil to the urea used and the temperature difference between heating and cooling.

〔Example〕

Next, the present invention will be explained with reference to Examples.

Example 1 80 g of urea was added to 450 d of methanol, and the mixture was stirred at 50° C. for 5 minutes in a 12-volume separating funnel.

(2) 45 g of an equal weight mixture of oleic acid and lylunic acid (both commercially available reagents) was added to the mixed solution, and the mixture was cooled to 10° C. for 20 minutes with stirring to form a urea adduct.

(3) Add 45% n-hexane at 10°C to the reaction solution of (2).
()- was added, stirred vigorously for 3 minutes while maintaining the temperature at 10°C, and then allowed to stand. The upper transparent hexane layer was separated and the solvent was distilled off under reduced pressure to obtain 20.8 g of non-added ester containing a large amount of highly unsaturated ethyl ester.

(4) Heat the lower methanol layer containing the urea adduct to 50°C for 20 minutes while stirring, add 50°C n-hexane 450°C to this, keep the temperature at 50°C, stir vigorously for 3 minutes, and then let it stand. did. The upper transparent hexane layer was separated and the solvent was distilled off under reduced pressure to obtain 22.3 g of additional component.
I got it.

(5) While keeping the lower methanol layer in (4) at 50°C, add 45 g of an equal weight mixture of oleic acid and lylic acid, and perform the following operations in the same order as (2), (3), and (4).
．． 6 g of non-added component and 22.2 g of added component were obtained.

The extraction solvent recovered in step (3) was used to extract the non-added ester, and the extraction solvent recovered in step (4) was used to extract the added ester.

(6) Repeat (5) one more time, 21.
2 g of non-added component and 23.9 g of added component were obtained.

After methyl esterifying the non-(=11 component and the additional component fatty acid) obtained in the 3-cycle test above, gas chromatography was performed to determine the ratio of sleic acid to lylunic acid of each component. The results are shown in Table 1.

Below is the margin Example 2 (1) Add 80 g of urea to 400 d of methanol,
The mixture was stirred and dissolved while maintaining the temperature at 0°C.

(2) 50Fd! The urea methanol solution of (1) was added to a three-way flask at a flow rate of 20 mt'/min and the ethyl ester of a fatty acid having 20 carbon atoms obtained by precision distillation of sardine oil ethyl ester was added as the main component. The fractions (raw material esters) were continuously fed and mixed with stirring.

(3) Inner diameter 5-1 installed in a constant temperature water tank kept at 5℃,
The mixed solution was continuously fed from the three flasks in (2) to a stainless steel pipe with a length of 1.8 m.

(4) 50rnI! A three-hole flask was maintained at 5°C, and the liquid discharged from the stainless steel tube (3) and 5't'n-hexane (20tf'/min) were continuously fed into the flask and mixed with stirring.

(5) A glass decanter with an inner diameter of 2.8 cm and a height of 15 cm kept at 5°C (Fig. 2) The mixture from the three-ring flask in (4) is continuously pumped through the center to separate one layer. Then, pour over the transparent n-hexane layer from the top of the decanter.
The extract was collected by distillation under reduced pressure to obtain a non-additive component containing highly unsaturated ethyl ester as a residual oil. In addition, n- containing a small amount of methanol recovered by distillation
Hexane was returned to step (4) and used for circulation.

(6) At the same time as (5), the methanol layer containing the urea adduct was extracted from the bottom of the decanter at a flow rate that kept the interface between the upper and lower layers at a constant height, and this was placed in a constant temperature water bath maintained at 50°C. The liquid was continuously fed into a stainless steel tube with an inner diameter of 5 mm and a length of 1.8 m.

(7) Keep a 50-volume three-loaf flask at 50°C, (6)
The liquid coming out from the stainless steel tube and the beef san (20 m
f/min) was continuously fed and mixed by stirring.

(8) Continuously feed the mixture from the three-lough flask in (7) through the center of a glass decanter with an inner diameter of 2.8 cm and a length of 15 cm kept at 50°C to separate the two layers, and then pour the mixture into two layers from the top of the decanter. The transparent n-hexane layer is separated by overflow, the filtration agent is distilled off and recovered under reduced pressure, and the residual oil is an additional component mainly composed of low unsaturated ethyl ester.
Ta.

In addition, the 1-hexane containing a small amount of methanol recovered by distillation was returned to the step (7) and recycled to 3゜(9) (
8) At the same time, extract the methanol layer containing urea from the bottom of the decanter at a flow rate that maintains the interface between the upper and lower layers at a constant height, and continuously feed this into the container containing the urea-methanol solution in step (1). , used in circulation.

The above series of continuous circulation steps were performed continuously for 5 hours, and 540
From the raw material ester of g, the non-added component of 2701; and 2
14 for 66g of additional ingredients. The fatty acid compositions of the raw ester, non-added components, and added components were measured by gas chromatography. The results are shown in Table 2.

Table 2 Example 3 (1) 40f methanol to 1.5ml water! , and 8 kg of urea were added and stirred and dissolved at 50°C.
)124! solution of (1) at a flow rate of /h and 1.2n/h
The same raw material ester used in Example 2 was continuously fed to the IJ heat exchanger at a flow rate of 5°C.
The urea adduct was formed by cooling to .

(3) The mixture of (2) was continuously fed to a countercurrent liquid-liquid extractor maintained at 5°C, and extracted with n-hexane at a flow rate of 10 p/hr at 5°C. The solvent in the n-hexane layer was distilled off and recovered under reduced pressure to obtain a non-added component mainly composed of highly unsaturated ethyl ester as a residual oil. In addition, the n-hexane containing a small amount of methanol that was distilled off and recovered was recycled and used as an extraction solvent.

(4) The methanol layer containing the urea adduct, which was the extraction residue of (3), was sent to an oyster-type heat exchanger and heated to 50° C. to decompose the urea adduct.

(5) The liquid discharged from the heat exchanger in (4) is continuously sent to a countercurrent distribution liquid-liquid extractor maintained at 50°C.
The mixture was extracted with n-hexane at 50°C. The solvent in the n-hexane layer was distilled off and recovered to obtain an additional component mainly composed of low unsaturated ethyl ester as a residual oil. In addition, n-hexane containing a small amount of methanol that was distilled off and recovered was recycled and used.

(6) The methanol layer containing urea, which was the extraction residue in (5), was continuously fed to the container in step (1) and used for circulation.

The above series of continuous circulation steps were carried out continuously for 8 hours.
．． 4.54 kg of non-added components and 4.17 kg of added components were obtained from 74 kg of raw ester.

The fatty acid compositions of the raw ester, non-added components, and added components were measured by gas chromatography. The results are shown in Table 3.

Table 3 Example 4 (1) Add 12 kg of urea to 401 methanol and add 60
The mixture was stirred and dissolved while maintaining the temperature at °C.

(2) At a flow rate of 1242/hr, the solution of (1) and 12
n-hexadecane and 2.6.1014 at a flow rate of E/h.
-Tetramethylbentate"can (both commercially available reagents) were continuously fed into an oyster-type heat exchanger and cooled to 20° C. to form urea adducts.

(3) The mixture of (2) was continuously fed to a countercurrent distribution liquid-liquid extractor kept at 20°C, and the flow rate was 20°C at a flow rate of 1012/hour.
Extracted with isooctane at ℃. The solvent in the isooctane layer was distilled off and recovered under reduced pressure to obtain a non-added component as a residual oil. Also, the isooctane containing a small amount of methanol that was distilled off and recovered was recycled and used as an extraction solvent.

(4) The methanol layer containing the urea adduct, which is the extraction residue of (3), was sent to the oysters) through an IJ type aging heat exchanger, and
The urea adduct was decomposed by heating to ℃.

(5) The liquid discharged from the heat exchanger in (4) was continuously fed as a countercurrent distribution liquid maintained at 60°C to an extractor and extracted with isooctane at 60°C at 101/hour. The solvent in the isooctane layer was distilled off and recovered to obtain an additional component as a residual oil. In addition, the isooctane containing raw methanol recovered by distillation was recycled and used as an extraction solvent.

(6) The methanol layer containing urea, which was the extraction residue in (5), was continuously fed to the container in step (1) and used for circulation.

7. Perform the above series of continuous circulation steps continuously for 8 hours.
48 kg of n-hexadecane and 2.6. +014-Tetramethylpentadecane from an equal mixture of 3.72 kg
of non-added component and 3.72 kg of added component were obtained.

The composition ratio of each component, n-hexadecane and 2,6.10.14-tetramethylpentadecane, was measured by gas chromatography. The results are shown in Table 4.

Table 4

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of the apparatus of the present invention. 1: Reaction tank 2: Extractor 3: Heating device 4: Extractor 5 Solvent distillation column 6: Solvent distillation column FIG. 2 is a cross-sectional view of the decanter used in Example 2. J- Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1. A raw material oil and urea are reacted in a reaction solvent to produce a urea adduct of oil, an unreacted oil is extracted from the reaction mixture with an extraction solvent, and the urea adduct in the reaction mixture is heated. A continuous urea addition fractionation method for oil components, which is characterized by decomposing the oil components through treatment, extracting the decomposed oil components with an extraction solvent, and reusing the remaining urea and reaction solvent. 2 Reaction tank 1 for reacting raw oil and urea in a reaction solvent, extractor 2 for extracting unreacted oil from the reaction mixture with an extraction solvent, heating device 3 for decomposing urea adducts
and an extractor 4 for extracting the decomposed oil using an extraction solvent.A continuous urea addition fractionation device for oil.