JP2009023930A - Method for producing glycerin derivative - Google Patents

Abstract

[PROBLEMS] To produce a high-yield glycerin derivative that is useful as a raw material for polymers such as polyester, polycarbonate, and polyurethane, an activator, a lubricating oil, a cosmetic composition, and an organic raw material for industrial synthesis, with reduced energy consumption. It is an issue to provide.
In the present invention, glycerin and dialkyl carbonate are reacted while extracting by-product methanol using a separation membrane. The separation membrane is preferably a zeolite membrane. The zeolite membrane is preferably Y-type.
[Selection figure] None

Description

  The present invention relates to a method for producing a glycerin derivative useful as a polymer composition such as polyester, polycarbonate and polyurethane, an activator, a lubricating oil, a cosmetic composition and an industrial organic synthesis material from glycerin.

  In recent years, fuels using reproducible raw materials (biomass) such as vegetable oils and animal oils have been developed. For example, biodiesel fuel, which is a representative fuel using biomass, is expected to greatly reduce the amount of fossil fuel used. Examples of a method for obtaining such biodiesel fuel include a method in which triglyceride contained in synthetic oil, vegetable oil, animal oil and the like is reacted with methanol in the presence of an alkali catalyst (Patent Document 1). However, the method for producing a fatty acid alkyl ester by transesterification of triglyceride and methanol produces a large amount of glycerin as a by-product. Therefore, effective utilization of glycerin produced as a by-product is awaited.

As a conversion technique for effectively utilizing glycerin, for example, Non-Patent Document 1 discloses a transesterification reaction between dimethyl carbonate and glycerin. However, in order to remove the produced methanol by distillation, a large-scale distillation facility is required, and a large amount of heat energy is consumed, which is not an efficient method.
In addition, since methanol and dimethyl carbonate form an azeotropic mixture, when methanol is distilled out of the reaction system by distillation, dimethyl carbonate as a raw material is distilled out of the reaction system together with methanol. As a result, the product yield decreases.
JP-A 56-120799 Green Chemistry 2005, 7, 529-539

  An object of the present invention is to solve the above-mentioned problems and to provide a method for producing a high yield glycerin derivative with reduced energy consumption.

  The present invention is a method for producing a glycerin derivative characterized in that glycerin and dialkyl carbonate are reacted while extracting by-produced alcohol using a separation membrane. The separation membrane is preferably a zeolite membrane. Furthermore, the zeolite membrane is preferably a Y-type zeolite membrane.

  According to the present invention, a glycerin derivative can be produced in a high yield economically and with reduced energy consumption. Thereby, glycerin derivatives can be used as polymer raw materials such as polyester, polycarbonate and polyurethane, activators, lubricating oils, cosmetic compositions, and industrial organic synthetic raw materials.

  The present invention is characterized in that glycerol and dialkyl carbonate are transesterified while extracting by-product alcohol using a separation membrane. There is no restriction | limiting in particular in the purity of the glycerol used by this invention. Commercially available glycerin can be used. Moreover, the glycerin after making triglyceride and methanol contained in vegetable oils, such as palm oil, react in the presence of an alkali catalyst, and stationary-separating can also be used.

  Examples of the dialkyl carbonate used in the present invention include dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, and ethyl propyl carbonate. Among them, dimethyl carbonate is preferably used. The purity of the dialkyl carbonate is not particularly limited. The dialkyl carbonate is not limited, but is 3 to 20 mol, preferably 5 to 10, with respect to 1 mol of glycerin in consideration of the conversion rate and economic efficiency of glycerin.

  In the transesterification reaction in the present invention, a catalyst is used. As a catalyst, the catalyst used for normal transesterification reaction, such as an alkali metal compound and an alkaline-earth metal compound, is used suitably, for example. Specifically, examples of the alkali metal compound include alkali metal alcoholates (lithium methylate, sodium methylate, potassium methylate, etc.) and alkali metal carbonates (lithium carbonate, sodium carbonate, potassium carbonate, etc.). And alkali metal hydroxides (lithium hydroxide, sodium hydroxide, potassium hydroxide, etc.). Examples of the alkaline earth metal compound include an alkaline earth metal alcoholate (magnesium methylate, etc.), an alkaline earth metal carbonate (magnesium carbonate, etc.), and an alkaline earth metal hydroxide (magnesium hydroxide). Etc.). These catalysts are used in an amount of 0.1 to 0.0001, preferably 0.05 to 0.001 mol per mol of glycerin.

  The reaction temperature of the transesterification reaction is 30 to 200 ° C, preferably 50 to 120 ° C. Further, the reaction pressure is preferably set corresponding to the reaction temperature in the range of atmospheric pressure to 1 MPaG (G indicates gauge pressure), and the atmosphere during the reaction is preferably an inert gas atmosphere such as nitrogen. . The reaction time (corresponding to the residence time when the reaction is performed continuously) varies depending on the reaction temperature and the amount of catalyst, but is preferably in the range of 1 to 24 hours.

  In the present invention, the by-produced alcohol is transesterified while being extracted out of the reaction system using a separation membrane. As a method for extracting alcohol, a pervaporation method in which alcohol is selectively permeated and removed from the mixed solution as alcohol vapor from a mixed solution containing alcohol, or alcohol vapor from the component vapor that forms the mixed solution with alcohol vapor. A vapor permeation method that selectively takes in and selectively removes alcohol is preferable, but a vapor permeation method is preferred. In the present invention, the high-concentration dialkyl carbonate vapor remaining on the non-permeate side of the membrane is preferably cooled and condensed and returned to the reaction mixture. Thereby, reaction can be advanced and conversion can be improved, without adding a dialkyl carbonate newly.

  Also, increase the partial pressure of alcohol vapor in contact with the separation membrane using a pressurized reaction system, or reduce the permeation side of the separation membrane to increase the partial pressure difference between the alcohol vapors on both sides of the separation membrane. Further, a gas other than alcohol (for example, air, nitrogen gas, etc.) can be made to flow as a sweep gas on the permeation side of the separation membrane, and the permeated alcohol vapor can be forcibly swept from the permeation side of the separation membrane. The separation membrane can be attached at any place suitable for the separation method. For example, the separation membrane may be attached directly to the reactor or incorporated in a line for circulating the reaction liquid. Furthermore, it reacts using the reactor etc. which were equipped with the distillation column, and after making mixed vapor | steam distill to an azeotropic composition with a distillation column, it can also make it contact with a separation membrane. Thereby, the separation efficiency can be further increased. Furthermore, in the present invention, before bringing the mixed vapor into contact with the separation membrane, it is preferable to superheat at about 2-3 ° C. or more, preferably 5 ° C. or more in order to maintain the separation efficiency of the separation membrane.

  The separation membrane used in the present invention is not particularly limited as long as it selectively permeates alcohol with respect to dialkyl carbonate. For example, polymer films such as polyimide, polycarbonate, polysulfone, polyetherimide, polyamideimide, films obtained by heat-treating these polymer films, partially carbonized films or carbon films obtained by heat-treating polymer films, ceramics A membrane, a zeolite membrane, or the like can be suitably used. Among these, a zeolite membrane is preferable from the viewpoints of heat resistance, solvent resistance, and separation performance.

Here, the zeolite membrane refers to a membrane in which zeolite is formed on a porous support. As types (structures) of zeolite, there are A type (LTA structure), X, Y type (FAU structure), T type (ERI, OFF structure), mordenite type (MOR structure), ZSM-5 type (MFI structure). Examples of those that selectively permeate methanol include Y-type zeolite membranes in which Y-type zeolite is formed into a membrane on a porous support.
The zeolite structure is a zeolite structure described in Non-Patent Document 2. There are sites for exchanging cations in zeolite, but there are no particular restrictions on the cations exchanged here, for example, H ⁺ , Li ⁺ , Na ⁺ , K ⁺ , Ca ⁺ , Cs ⁺ , NH ₄ ⁺ , Transition metal cations, and the like, and these cations may be mixed. As the support for forming the zeolite membrane, a porous support such as alumina, stainless steel, zirconia, mullite, silica, silicon nitride, silicon carbide, or organic polymer is used.
[Non-Patent Document 2] Atlas of Zeolite Structure types (WM Meier, DH Olson, Ch. Baerlocher, Zeolites, 17 (1/2), 1996)
These films may be uniform films, asymmetric films, or composite films. Furthermore, the form of the membrane may be any of a flat membrane type, a tubular type, a hollow fiber type, a spiral type and the like.

The zeolite membrane is prepared by colloidal silica containing Si, sodium silicate, silicon source such as alkoxysilane (such as tetraethoxysilane), aluminum containing Al, aluminum metal such as aluminum foil, aluminum nitrate, aluminum hydroxide, aluminum. An aluminum source such as sodium acid and isopropoxyaluminum, a monovalent cation source such as sodium hydroxide and potassium hydroxide containing M ⁺ (M is Na, K) and water, Si / Al = 10 to 60, Na /Si=0.2-2, water / M ⁺ = a method of putting the support in a gel solution prepared at a composition ratio of 50-300 and heating, or a silicon source and an aluminum source having a similar composition ratio Same as zeolite membrane previously formed on the support in the mixed solution containing monovalent cation source and water A support on which a zeolite crystal having a crystal structure is uniformly coated by a method such as rubbing, dip coating or filtration is immersed, and the temperature is 80 to 120 ° C., preferably 95 to 110 ° C., and 3 to 10 hours, preferably 4 It is carried out by a method of heating for ˜7 hours.

  An example of the manufacturing apparatus of the glycerol derivative in this invention is demonstrated. The raw material glycerin, dialkyl carbonate, catalyst, and a solvent as required are added to a reaction vessel equipped with heating means and stirring means, and stirred while heating to a predetermined temperature. A mixed vapor containing alcohol and dialkyl carbonate by-produced from the reaction mixture is generated and introduced into the separation membrane device. The permeation side of the separation membrane of the separation device is decompressed by a vacuum pump. In the separation membrane apparatus, the mixed vapor comes into contact with the separation membrane, and alcohol vapor selectively permeates through the membrane. On the permeate side of the membrane, the alcohol vapor is highly concentrated, condensed by the cooling device, and recovered in a recovery container equipped with cooling means. The mixed vapor flowing on the non-permeate side of the membrane has a high concentration of dialkyl carbonate, and is returned to the reaction vessel.

  The reaction in the present invention can be carried out either batchwise or continuously. In the transesterification reaction, a solvent is not particularly required, but there is no problem in using it as long as it is inert in the reaction system. When the solvent has a low boiling point and is vaporized together with the alcohol and contained in the mixed vapor, a solvent that is more difficult to permeate the separation membrane than the dialkyl carbonate vapor is preferable. Specifically, benzene, toluene, xylene, petroleum ether, hexane, heptane, octane, cyclohexane, methylcyclohexane, dichloromethane, dichloroethane, diethyl ether, tetrahydrofuran, tert-butyl methyl ether, and the like can be used.

  The glycerin derivative obtained in the present invention refers to a mixture of glycerin carbonate represented by the formula (1), (2-oxo-1,3-dioxolane) methyl alkyl carbonate obtained by the formula (2), and other glycerin derivatives. Cyclic carbonates can be included. For example, the ratio of the total weight of glycerin carbonate and (2-oxo-1,3-dioxolane) methyl alkyl carbonate in the glycerin derivative is 35 to 100. Among them, a glycerin derivative mainly composed of (2-oxo-1,3-dioxolane) methyl alkyl carbonate cannot be produced unless the by-produced alcohol is continuously distilled out of the system. The present invention capable of distilling off alcohol is useful as a method for producing (2-oxo-1,3-dioxolane) methyl alkyl carbonate in high yield.

（式中、Ｒは、メチル基、エチル基、プロピル基を示す）

(In the formula, R represents a methyl group, an ethyl group, or a propyl group)

  Hereinafter, the present invention will be described in more detail with reference to examples. In addition, this invention is not limited to a following example.

[Yield of glycerin derivative]
A part of the reaction solution was extracted by an internal standard method (biphenyl was used for the internal standard), analyzed using gas chromatography, and calculated based on glycerin.

[Permeability of Y-type zeolite membrane]
Evaluation was carried out by selectively permeating methanol from a methanol / tert-butyl methyl ether (10/90 wt / wt) mixture heated to 50 ° C. by a pervaporation method. The separation factor was calculated by the following formula.

ここで、ＰＭは、透過液中のメタノールの重量％、ＰＥは透過液中のｔｅｒｔ−ブチルメチルエーテルの重量％であり、ＦＭは、混合溶液中のメタノールの重量％、ＦＥは混合溶液中のｔｅｒｔ−ブチルメチルエーテルの重量％を表わす。

Here, PM is the weight percent of methanol in the permeate, PE is the weight percent of tert-butyl methyl ether in the permeate, FM is the weight percent of methanol in the mixed solution, and FE is the weight percent in the mixed solution. It represents the weight percentage of tert-butyl methyl ether.

[Reference Example 1] Production of Y-type zeolite membrane A sodium silicate aqueous solution, sodium aluminate, sodium hydroxide and water were mixed with SiO ₂ / Al ₂ O ₃ = 26, Na ₂ O / SiO ₂ = 0.89, H ₂ O. / _Na 2 O = 78 were mixed so that the composition of the. A mullite tube (made by Nikkato, pore diameter of about 1.5 microns, outer diameter of 12 mm, inner diameter of 9 mm, length of 100 mm) in which Y-type zeolite crystals (manufactured by Tosoh, HSZ-320NAA) are applied to the surface by rubbing in the mixed solution. Was immersed and heated at 100 ° C. for 6 hours. After completion of the reaction, it was washed with distilled water and dried at 80 ° C. for 20 hours. The separation factor of the obtained Y-type zeolite membrane was 470.

[Example 1]
The reaction apparatus is shown in FIG. To a 300 ml flask 3, 0.4 g (0.003 mol) of potassium carbonate, 9.2 g (0.1 mol) of glycerin, and 90.1 g (1.0 mol) of dimethyl carbonate were added. The Y-type zeolite membrane 1 obtained above with one end closed by a glass stopper 8 and the other end connected to a vacuum pump 13 was attached to the upper part of the flask. It moved to the oil bath 4 heated beforehand at 95 degreeC, and was heated and refluxed under atmospheric pressure for 4 hours and 30 minutes. During the reaction, the periphery of the zeolite membrane 1 was heated to 90 ° C. with a ribbon heater 2 from the outside. Methanol generated by the reaction was removed from the system by the Y-type zeolite membrane 1 and collected in a trap 11 cooled with liquid nitrogen 12. After the reaction, the container was taken out from the oil bath 4 and cooled to room temperature. A part of the reaction solution was extracted, internal biphenyl was added, diluted with acetone, and (2-oxo-1,3-dioxolane) methyl methyl carbonate and glycerol carbonate were quantified by gas chromatography. As a result, glycerin was not detected, and the yield of (2-oxo-1,3-dioxolane) methyl methyl carbonate was 80.2%, and the yield of glycerin carbonate was 3.8%. In the trap 11, 9.20 g of liquid was collected. A part of the liquid was extracted and quantified by gas chromatography. As a result, it was found that methanol was 83.1 wt% and dimethyl carbonate was 16.9 wt%. As a result, it has been clarified that glycerin can be converted in a high yield by converting glycerin while greatly reducing the consumption of heat energy and useful as a starting material for chemical raw materials.

[Example 2]
The same operation as in Example 1 was performed except that the amount of dimethyl carbonate used was changed to 31.6 g (0.35 mol). A part of the reaction solution was extracted, internal biphenyl was added, diluted with acetone, and (2-oxo-1,3-dioxolane) methyl methyl carbonate and glycerin carbonate were quantified by gas chromatography. The yield of (2-oxo-1,3-dioxolane) methyl methyl carbonate was 23.9%, and the yield of glycerol carbonate was 4.3%. In the trap 11, 8.62 g of liquid was collected. A part of the liquid was extracted and quantified by gas chromatography. As a result, 98.4 wt% of methanol and 1.6 wt% of dimethyl carbonate were contained.

[Comparative Example 1]
In the reaction apparatus shown in FIG. 1, the same operation as in Example 1 was performed except that the Y-type zeolite membrane 1, the ribbon heater 2, the trap 11 and the vacuum pump 13 were not used. A part of the reaction solution was extracted, internal biphenyl was added, diluted with acetone, and (2-oxo-1,3-dioxolane) methyl methyl carbonate and glycerol carbonate were quantified by gas chromatography. As a result, when the Y-type zeolite membrane was not used, glycerin and (2-oxo-1,3-dioxolane) methyl methyl carbonate were not detected, and the yield of glycerin carbonate was 37.5%.

1 is a schematic view of a reaction apparatus for carrying out the present invention.

Explanation of symbols

1 Zeolite membrane 2 Ribbon heater 3 Flask 4 Oil bath 5 Stirrer 6 Reaction liquid 7 Glass tube 8 Glass plug 9 Cooling tube 10 Nitrogen 11 Trap 12 Liquid nitrogen 13 Vacuum pump

Claims (3)

A method for producing a glycerin derivative, characterized in that glycerin and dialkyl carbonate are reacted while extracting by-produced alcohol using a separation membrane. The method for producing a glycerin derivative according to claim 1, wherein the separation membrane is a zeolite membrane. The method for producing a glycerol derivative according to claim 2, wherein the zeolite membrane is a Y-type zeolite membrane.

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