JPH0613610B2 - Method for producing crown ether polymer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a crown ether polymer.

(Prior Art) Since the discovery of Dr. Pederson in 1967, crown ether compounds have been found to have unique properties one after another.
It has become very important in the fields of basic chemistry and industrial fields of biochemistry. Its important properties are the selective capture of metal cations and the separation and transport of metal ions based on them, and the impartation of solubility to organic solvents such as inorganics and alkali metals, which are not usually dissolved in organic solvents, and stereochemistry of crown ethers. Another application is optical resolution agents. Especially, it is very important as a metal cation sensor.

However, crown ether has many problems such as solubility, physiological action and toxicity. Therefore, studies have been made to improve these problems by polymerizing or fixing / insolubilizing the crown ether.

As a method for polymerizing, immobilizing and insolubilizing the crown ether, for example, JP-A-56-141312 discloses a method in which a vinyl group is added to the crown ether and the crown ether is immobilized by irradiation with radiation. Further, JP-A-56-47405 proposes immobilization by an Friedel-Craft reaction of an aromatic crown compound and chloromethylated crosslinked polystyrene.

Japanese Unexamined Patent Publication (Kokai) No. 52-109600 proposes a method in which an amino group is introduced into a crown compound and immobilized by a reaction with an epoxy group.

In these methods, it is very difficult to introduce a functional group into the crown compound and the yield is low even if a process or a functional group is introduced. The problems mentioned above remain.

(Problems to be Solved by the Invention) The present invention solves various problems of low-molecular weight crown ethers, and at the same time, solves problems in the conventional immobilization of crown ethers.

An object of the present invention is to propose a method for polymerizing and immobilizing crown ether in a high yield by a simpler process and immobilizing it on a wider range of carriers.

(Means for Solving Problems) The method of the present invention is characterized by activating a crown ether compound in low temperature plasma to polymerize and insolubilize it.

The crown ether compound used in the present invention may be any crown ether compound that has been used so far and is not particularly limited. For example, either a monocyclic crown ether represented by the following general formula or a heterocyclic crown ether represented by the general formula may be used.

_{m 1, m 2, m 3} : 1 or more R _1, R _2: represents H or a hydrocarbon residue.

The above-mentioned crown ether compound (hereinafter abbreviated as crown ether compound) may contain a halogen element, a benzene ring, a cyclohexane ring and one or more of these various derivatives.

For example, dibenzo18-crown-6, dicyclohexyl-18-crown-6, cyclohexyl12-crown-4, benzo15-crown-5, tert-butylbenzo15-crown-5, tribenzo18-crown-6, which have been conventionally used in large numbers, are used. 6, tetrabenzo 24-crown-8 and the like can also be used.

Further, crown ether compounds which cannot be washed by the general formula and, for example, the following compounds can also be used.

The plasma used in the present invention refers to so-called low temperature plasma, and the ionized gas plasma can be generated by any known method for generating such plasma. For example, J. R. Hollahan and A.
T. Bell's "Applied Technology of Plasma Chemistry", Wiley, New York 1974 and M. Shen's "Plasma Chemistry of Polymers" Decker New York 1
976. That is, the monomer can be put under vacuum on the side of the parallel plate electrode connected to the high frequency generator, and plasma can be generated using the parallel plate outside or inside the vacuum chamber. An external induction coil may be used to generate an electric field to generate a plasma of ionized gas, or the oppositely charged electrodes may be directly placed in a vacuum chamber with a space therebetween to generate plasma.

The crown ether compound usually has a high boiling point and has a low vapor pressure at room temperature, although it depends on the molecular weight, the kind of the substituent, and the like.

The low-temperature plasma effectively activates and polymerizes the monomer in the above-mentioned degree of vacuum, and when the vapor pressure of the crown ether is less than this, it is necessary to heat the crown ether to increase the vapor pressure. . As a heating method, any one of heater heating, high frequency heating, far infrared heating and laser heating may be used, but it is important to heat for as short a time as possible. Polymerization of crown ether by low-temperature plasma changes from grease (liquid) state-film (film) state-particle (powder) state depending on plasma polymerization conditions.

The polymer is usually formed on a sheet of paper, glass, silica gel, polymer, etc., fibers or fine particles and polymerized / immobilized, but without using such a carrier, it is directly polymerized on the electrode to produce a polymer. May be collected and molded. The correlation of the primary (chemical) structure between the monomer and the polymer changes depending on the type of the monomer and the plasma polymerization conditions.

It can be seen that the plasma polymerized product of the crown ether compound has no solubility in organic solvents such as alcohol, ether, pyridine, chloroform, acetone, benzene, formic acid and dimethylformamide and is a crosslinked polymer.

However, the swelling property with respect to the organic solvent changes depending on the polymerization conditions. It is difficult to identify the structure and chemical structure of plasma polymer. IR, NMR, X-ray, electron microscope, and other measurements, and metal ion adsorption, complex formation with various salts, etc. can be used for tentative evaluation, but typical chemical structures of monomers,
For example, it is necessary to select conditions under which most of the ether ring remains.

In general, it is not easy to leave a general structure of a monomer whose chemical structure is likely to be destroyed by a polymerization method, light heat or the like even by plasma polymerization. In such a monomer, for example, a monomer is placed between electrodes, and plasma other than the monomer, for example, an inert gas such as argon, N ₂ , H ₂ , He, and CO ₂ and other polymerized monomers such as acrylic acid and methacrylic acid, Plasma of a monomer such as vinylpyrrolidone, vinyl pyridine, and 2-hydroxyethyl methacrylate, which is easily polymerized, is generated in advance, and heating is performed for a short time in the plasma to plasmanize and polymerize the target monomer. In addition, the susceptibility of the primary structure of water and the monomer is changed depending on the conditions of plasma polymerization. That is, when the primary structure of the monomer is to be left, the plasma irradiation time is reduced. Generally, plasma polymerization of crown ether is
It is usually 10 minutes or less, preferably 5 minutes or less, and a method of applying a high frequency in a pulsed manner is also preferable. It is preferable to combine the method of lowering the plasma polymerization time and the plasma output, the vacuum degree, or the substrate temperature. Regarding the plasma output, if the output is large, the structure of the monomer is easily broken, but if the output is lowered too much, the polymerization will not proceed sufficiently and the residual rate of the monomer will increase or the molecular weight of the product will not increase sufficiently and will dissolve in the solvent etc. To do Therefore, it is important to determine the output based on these tradeoffs. The high frequency output in the case of crown ether polymerization is usually 10 to 300 W, preferably 50 to
Of course, the high frequency output of 200 W needs to be appropriately selected according to the intended use.

The degree of vacuum also shows the same tendency and effect as the output, and when the degree of vacuum is lowered, the progress of polymerization is not sufficient and the physical properties of the polymer are not sufficient. On the other hand, if the degree of vacuum is too high, the energy of the plasma becomes too high, and a polymer that leaves almost no monomer structure is formed, or a film or powder having an extremely high degree of cross-linking is formed. It is difficult to get in and out of the substance, and the performance of the polymer cannot be expressed even if the properties of the monomer remain. Vacuum is usually 10 ^-5
˜100 Torr, preferably 10 ⁻⁴ to 10 Torr, more preferably 10 ^{−3 to 1} Torr.

The temperature of the substrate has little relation to the essential mechanism of plasma polymerization, but when the substrate temperature is high, the molecular weight of the polymerization product, and when the crosslinking is small, the product vaporizes and diffuses.

Further, when the substrate temperature is low, unactivated monomer is adhered and solidified due to diffusion due to a temperature gradient, resulting in deterioration of polymerizability.

(Effect of the invention) The method of the present invention is extremely difficult to handle and dispose of due to its toxicity, physiological action, metal ion adsorbability, etc., and due to its high price, the crown ether compound has been extremely costly even with a small loss. It is an extremely effective method from an engineering point of view that the monomer can be directly and one-step plasma polymerized and fixed instead of the conventional method which cannot be said to be necessarily high in yield.

In addition, the plasma polymer of the crown ether compound is liquid ~
The form of the product can be arbitrarily selected from the viewpoint of film form to powder form. In particular, the method of the present invention is particularly effective when used for a metal ion sensor or the like because a uniform and very thin film is required.

Since the method of the present invention has the above-mentioned characteristics, it is extremely useful for producing a material for adsorbing and separating metal ions by a membrane, a metal ion sensor, an immobilized catalyst, an optical resolution material and the like.

Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1 FIG. 1 shows the plasma polymerization apparatus used this time. Reference numeral 1 is a high frequency power supply (RF power supply), and a high frequency power supply of 13.56 MHz was used here. The high frequency generated in 1 is 19
10cm diameter in the reactor 2 through the matching box
It is communicated with the φ electrode 3. When a high frequency is applied between the electrode 3 and the grounded pair of electrodes 5, plasma is generated inside the reactor. The crown ether compound 20 is charged in a Tastal heating container 21 in an amount of 0.1 g, and the heating power source 22 is used to change the heating voltage to change the supply amount of the monomer into the plasma. The gas or other monomer that generates plasma can be supplied from 16-18. Here, the crown ether compounds shown in Table 1 were used.

The pressure of the reaction vessel was adjusted to 10 ^-2 torr while supplying nitrogen gas from 17 while evacuating the reaction vessel with a vacuum pump 9. A cellulose acetate porous membrane (pore size 0.45 μ) was used as the polymerization substrate.

A high frequency voltage is applied to the electrodes to first generate nitrogen plasma. The high frequency output was 100W. Then, the voltage of 22 was increased to vaporize the crown ether. At the same time as crown ether was vaporized, the plasma color became slightly bluish. The vaporization of crown ether was completely completed in 3 to 5 minutes, and plasma generation was stopped at the same time.

The porous film having the crown ether polymerized film formed thereon was taken out from the reactor, washed with ethanol to wash away unreacted crown ether, and then dried indoors.

2 and 3 show the ATR of the Expp No-6 and a true copy of a scanning electron microscope. From FIG. 2 that the plasma polymer has a functional group of a monomer, and from FIG. 3 that the plasma polymer is added in the form of a flat film or partially in the form of granules on the serirose acetate porous film, and It can be seen that some of the polymers formed particles.

Example 2 In the composite film of Example 1, the crown ether polymer film was 0.0
2 g is attached, and KI. KSCN. The composite membrane was dipped in each methanol solution of NH ₄ SCN to form a complex with a salt.
The complex-forming ability of the crown ether polymer was measured from the decrease in the salt concentration in each solution, and KI / polymer = 0.6 / 1 (mol / mol), KSCN / polymer = 0.57 / 1 (mol, Mol), NH ₄ SCN / polymer = 0.4 / 1 (mol / mol).

[Brief description of drawings]

FIG. 1 shows a cross-tube type plasma polymerization apparatus, 1 is a radio frequency (RF) power supply, 2 is a glass reactor, 3 is an upper electrode, 5
Is a substrate (lower electrode), 4 is a sample for plasma polymerization, 21 is a container for heating a monomer, and 20 is a monomer. FIG. 2 shows the results of ATR. A is the dicyclohexyl 18-crown-6 monomer, B is the cellulose acetate porous membrane, and C is the ATR spectrum of the cellulose acetate porous membrane carrying the plasma polymer of dicyclohexyl 18-crown-6. Figure 3 (electron micrograph) shows dicyclohexyl 18-
The scanning electron microscope photograph of the cellulose acetate porous film carrying the plasma polymer of Crown-6 is shown. (Magnification 10
00 times)

Claims (4)

[Claims] 1. A method for producing a crown ether polymer, which comprises activating a crown ether compound in a low-temperature plasma for polymerization and insolubilization. 2. The method according to claim 1, wherein the crown ether compound is vaporized and introduced into the low temperature plasma. 3. The method according to claim 1 or 2, wherein vapor of a crown ether compound is introduced between the electrodes for activation. 4. A low-temperature plasma is supplied at a vacuum degree of 10 ^{-5 to} 100 Torr.
The method according to claim 1, which is generated by