JPS647994B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides novel biscrown ether derivatives,
The present invention relates to a method for producing the same and a selective ion extractant containing the same. The biscrown ether derivative of the present invention is a new compound that has not been described in any literature, and has the general formula [In the formula, R ¹ and R ² represent a hydrogen atom or a lower alkyl group, and n represents an integer of 3 to 6], and includes trans and cis forms. In the above general formula [], R ¹ and R ² are the same or different and represent a hydrogen atom or a lower alkyl group. Lower alkyl groups include straight chain or branched ones having 1 to 6 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl and the like. The biscrown ether derivative represented by the above general formula [] of the present invention has photoresponsive structural changes,
In other words, they have the property of causing trans-cis isomerization when irradiated with light, and they also have a unique ability to form complexes with various metal ions. Since these metals have different complex-forming abilities, it is possible to selectively extract or concentrate the metal ions by using these. Representative examples of the compounds of the present invention are as follows.

【table】

【table】

[Table] The biscrown ether derivative represented by the above general formula [] of the present invention can be produced by various methods, but the following method can be mentioned as a preferred production method. That is, the general formula [In the formula, R ¹ , R ² and n are the same as above] A compound represented by the following may be reduced in the presence of an alkali and a reducing agent. The compound represented by the above general formula [] is described, for example, in J.Am.Chem.Soc. 98 , 5198
(1976) or in accordance with the method described. In the above, various types of alkali can be used, and alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, etc. are particularly preferred. These can be advantageously used in the form of aqueous solutions, but they can also be used in the form of solutions in suitable solvents, such as alcohol solutions. Further, as the reducing agent in the above, ordinary metal powder such as zinc powder, iron powder, aluminum powder, magnesium powder, etc. can be used. Among these, zinc powder is particularly preferred. The reduction reaction of the compound represented by the above general formula [] can be carried out, for example, in accordance with the production of azobenzene (Practical Organic Chemistry,
3rded (Longmans, London, 1959), p631]. That is, the reaction can be carried out by stirring and heating the raw material compound represented by the general formula [] in ordinary water, a suitable organic solvent, or a mixed solvent thereof in the presence of the alkali and reducing agent described above. Suitable organic solvents include alcohols such as methanol, ethanol, n-propanol, isopropanol, n-
Butyl alcohol, aromatic hydrocarbons such as benzene, toluene, chlorobenzene, etc. can be used. The amount of alkali and reducing agent to be used with respect to the raw material compound is not particularly limited and can be determined as appropriate as long as the above reduction reaction proceeds. is used so that it becomes strongly alkaline.
The heating temperature can also be determined arbitrarily, but it is usually 50 to 90℃.
The temperature is preferably about 60 to 80°C, and the reaction is generally completed in about 3 to 6 hours. In addition, according to the above reduction reaction, some hydrazo compounds may be generated in the reaction system, but in this case, for example, by separating the reducing agent used in the reaction and blowing air into the reaction mixture, the above hydrazo compounds can be removed. can be oxidized to obtain the desired derivative represented by the general formula []. After completion of the reaction, the target compound can be isolated and purified by conventional means such as recrystallization, solvent extraction, chromatography, etc. In this way, the biscrown ether derivative of the present invention represented by the general formula [] is obtained. This usually has the form of trans form, and the trans form can be isomerized to the cis form by dissolving it in a suitable organic solvent and irradiating it with light, and the cis form can be left standing under dark conditions. It has the characteristic of gradually returning to its original trans form (photoresponsive structural change). In addition, the above-mentioned trans isomer and cis isomer each have a unique ability to form complexes with various metal ions, such as alkali metal ions such as Na, K, Li, and Rb. Each ion can be extracted, separated or concentrated from a liquid containing two or more metal ions by utilizing the difference in complex forming ability. Furthermore, the above-mentioned trans isomer and cis isomer also differ in their ability to form a complex with the same metal ion in a solvent based on the difference in their steric structure, and this complex formation ability is different between two different metals. Between ions such as Na ⁺ ions and K ⁺ ions,
The trend may reverse. In fact, for example, the derivative of the present invention obtained in Example 1 described below, in the form of trans form, has almost no ability to form a complex with K ⁺ ions, and selectively forms complexes with Na ⁺ ions; In the cis form, on the other hand, it hardly forms a complex with Na ⁺ ions, but selectively forms a complex with K ⁺ ions. Therefore, the biscrown ether derivative of the present invention can contain, for example, Na ⁺ ions and K ⁺ ions by utilizing the combination of its unique ability to form complexes with various metal ions and photoresponsive structural changes. It is possible to selectively separate or isolate each ion from a mixed solution with an extremely efficient extraction operation, or to collect trace metal ions dissolved in water or the like to obtain a concentrated solution of desired ions, etc. It is useful as a selective extractant for various metal ions. When using the biscrown ether derivative of the present invention as the above-mentioned selective ion extractant, for example, the derivative of the present invention in the trans form is dissolved in a water-insoluble organic solvent such as o-dichlorobenzene. It may be brought into contact with a sample aqueous solution containing two or more types of metal ions. Through this contact, large metal ions that are capable of forming complexes with the trans isomer are collected by the trans isomer and transferred to the organic layer.
Thus, in the aqueous layer, metal ions having a low ability to form complexes with the trans isomer are concentrated. Further, the metal ions collected in the trans isomer can be easily transferred into the aqueous solution by back-extracting the organic layer with, for example, an aqueous hydrochloric acid solution, and thereby can be isolated. Further, operations similar to those described above can also be performed under light irradiation conditions using, for example, a high-pressure mercury lamp. In this case, each metal ion is separated mainly due to the difference in its ability to form a complex with the cis form. In the above case, when a metal ion exhibiting a greater ability to form complexes under light irradiation conditions than under dark conditions is transferred to the organic layer, the organic layer can be formed by simply leaving it in contact with the aqueous layer under dark conditions. , the metal ions move to the aqueous layer and are separated without any back extraction. This is because when the light irradiation is stopped, the cis form that has collected the metal ions isomerizes into the trans form, and since the complex formation of the trans form is smaller than that of the cis form, the collected metal ions are released. Based on. Contrary to the above, when it is desired to extract and separate metal ions that exhibit a smaller complex-forming property under light irradiation conditions than under dark conditions, after mixing and contacting a sample aqueous solution and a water-insoluble organic solvent solution of the derivative of the present invention under dark conditions, organic The layers may be separated and left in contact with the aqueous layer under light irradiation conditions. In particular, the derivatives of the present invention can be used in combination with appropriate light irradiation as described above to obtain metals that have a high ability to form complexes with the trans form but have a low ability to form complexes with the cis form, and vice versa. By using a mixed system of metal ions in which the complex formation with the cis-isomer is small, but the complex formation with the cis-isomer is large, each metal ion can be separated with very high selectivity. Extraction test examples are listed below to clarify the characteristics of the selective ion extractant of the present invention. <Extraction Test Example> Extraction of alkali metal ions using methyl orange as a counter ion is performed as follows. That is, an aqueous solution containing methyl orange (8.10×10 ⁻⁶ M) and alkali hydroxide (0.010 M) is prepared. Separately, an o-dichlorobenzene solution containing 3.00×10 ⁻⁴ M of biscrown ether (trans isomer) of formula [] obtained in Example 1 described later is prepared. Next, without irradiation with light, 5 ml each of the above aqueous alkali hydroxide solution and o-dichlorobenzene solution were combined, extracted by vigorous shaking for 2 minutes on a Vortex mixer, and extracted at 30°C.
Allow to equilibrate by holding on the bath for 3 minutes. A portion of the aqueous phase is taken and the absorption spectrum of methyl orange in the aqueous phase is measured. Above, place 5 ml of the above o-dichlorobenzene solution in a Pyrex test tube and irradiate it with a 500 W high-pressure mercury lamp at a distance of 12.5 cm at room temperature.The same procedure as above is used except that the o-dichlorobenzene solution containing the cis isomer is used. and measure the absorption spectrum of methyl orange in the aqueous phase. Separately, the absorption spectrum of methyl orange in the aqueous phase is measured in the same manner except that pure o-dichlorobenzene is used as a control. The extraction rate is determined from the difference between the absorption spectrum when extracted without light irradiation and the absorption spectrum when extracted after light irradiation with respect to the reference absorption spectrum. The results are shown in Table 2 below.

[In the formula, Extrans indicates the extraction rate of the trans isomer, and Excis indicates the extraction rate of the cis isomer. ]

actually reaches 238 times. (iv) Although Li ⁺ ions and Rb ⁺ ions are not as selective as K ⁺ ions, the cis-isomer still exhibits greater extraction ability. As is clear from the above extraction test example, the biscrown ether represented by the formula [] of the present invention is
It has a photoresponsive cis-trans isomerization ability, and has the unique property that the ability to form complexes with metal ions is greatly different between the cis and trans forms. It can be seen that it can be advantageously used as an ion extractant in various applied fields such as analytical chemistry. EXAMPLES Below, in order to explain the present invention in more detail, production examples of the biscrown ether derivatives of the present invention and examples of their use will be given as Examples. Example 1 10 g of 4'-nitrobenzo-15-crown-5
was dissolved in 100 ml of 90% methanol in which 6 g of sodium hydroxide had been dissolved, and 8 g of zinc powder was added little by little while stirring at 70°C, and the mixture was allowed to react under low reflux for 5 hours. The reaction mixture is heated and the zinc dust is washed with hot methanol. Combine the solution and cleaning solution,
While heating to 50°C, air is blown in to oxidize some of the hydrazo compounds formed into azo compounds. Then, it is neutralized with hydrochloric acid and methanol is distilled off. The resulting residue was extracted with 300 ml of chloroform, the chloroform phase was concentrated to 50 ml, and this was added with 50 ml of acetone.
ml, a dark brown resinous substance precipitates out. The precipitate is separated and the liquid is dried under reduced pressure to obtain brown crystals. By recrystallizing this from acetic acid, 2.5 g of biscrown ether (in the general formula [], R ¹ = R ² = H, n = 4, Compound No. 2 in Table 1, trans isomer) in the form of yellow needles was obtained. obtain. Melting point: 187-188℃ Elemental analysis (as C ₂₈ H ₃₈ N ₂ O ₁₀ ): C (%) H (%) N (%) Calculated value 59.77 6.82 4.98 Actual value 59.57 6.94 4.82 Mass spectrometry: M ⁺ = 563 IR Analysis (KBr): 1590 cm ^-1 (v _N=N ) 1120-1140 cm ^-1 (v _COC ) Ultraviolet spectrum (in o-dichlorobenzene): As shown as curve 1 in FIG. λ _nax = 376 nm (ε _nax = 26700) When the trans isomer obtained above was irradiated with light from a high-pressure mercury lamp in o-dichlorobenzene, an absorption peak at 376 nm was observed in the ultraviolet spectrum as shown as curve 2 in Figure 1. decreased (ε _nax =
16300). Then, when the o-dichlorobenzene solution after light irradiation was extracted with a 0.01M KOH aqueous solution and the ultraviolet spectrum of the aqueous phase was measured, there was no absorption peak at 376 nm, and there was no absorption peak at 445 nm, as shown as curve 3 in Figure 1.
An absorption maximum (ε _nax = 2890) appeared, confirming the cis isomer. Also, as a result of conversion from the decrease in absorption at 376 nm above, the cis and trans forms formed under light irradiation in o-dichlorobenzene are in equilibrium at (cis/trans) = 51.4/48.6 (molar ratio). It turns out that there is. When the solution after light irradiation was left under dark conditions, all of the cis isomers changed to trans isomers. In addition, the compound of the present invention obtained above was dissolved in various solvents and then irradiated with light to generate the cis isomer, and the isomerization rate to the trans isomer under dark conditions was measured by ultraviolet absorption spectroscopy. A relationship was established. The results were as shown in Table 3 below.

[Table] In general, the cis→trans isomerization rate of azo compounds is higher in polar solvents, but in the biscrown ether of the present invention, as is clear from Table 3 above, in nonpolar solvents (benzene) There is almost no difference in the isomerization rate between the medium and the polar solvent (o-dichlorobenzene). This is thought to be because the cis form is a more polar molecule than the trans form and is therefore stabilized in polar solvents. Furthermore, the rate of cis→trans isomerization decreases in a solvent containing water. This is presumed to be attributable to the interaction between water molecules and the crown ether moiety. Examples 2 to 5 In Example 1 above, 4'-nitrobenzo-15-
Instead of crown-5, 4'-nitrobenzo-12-crown-4, 4'-nitrobenzo-18-crown-
Similarly, using 6,5'-methyl-4'-nitrobenzo-18-crown-6 and 3',5'-dimethyl-4'-nitrobenzo-15-crown-5, the first
Compounds Nos. 1, 3, 6 and 7 (all trans forms) listed in the table were obtained. The formation of each of these compounds was confirmed by elemental analysis, IR analysis, and ultraviolet spectrum analysis. Example 6 0.05M methyl orange, 0.05M KOH and
Example 1 of 0.1M aqueous solution of 100ml of 0.05M NaOH
Extract with 100 ml of o-dichlorobenzene solution containing the biscrown ether (trans form) obtained in .
Separate the o-dichlorobenzene solution and add it to 100
Back-extract with ml of 0.1N HCl aqueous solution. When the 0.1N HCl aqueous solution obtained in this way was analyzed using an atomic absorption spectrometer, it was found that 0.0002M K + and 0.018M K ⁺
It was found that it contains Na ⁺ . This result shows that Na ⁺ was selectively concentrated 90 times in the above extraction operation from a mixed aqueous solution of equimolar K ⁺ and Na ⁺ . When a similar operation was performed using a light-irradiated o-dichlorobenzene solution, it was found that the
0.017M K ⁺ and 0.010M Na ⁺ in 0.1N HCl aqueous solution
It contained. From this result, under light irradiation conditions,
It was found that K ⁺ was extracted in excess. When K ⁺ is extracted under light irradiation, if the o-dichlorobenzene solution is left in contact with an aqueous solution, the cis form returns to the trans form, and most of the K ⁺ moves to the aqueous phase. Therefore, in this case, the operation of back extraction with an aqueous HCl solution can be omitted.
That is, 100ml of an aqueous solution containing 0.05M KOH, 0.05M NaOH, and 0.05M methyl orange was irradiated with 0.1M
O-dichlorobenzene solution containing the compound of the present invention
Extract with 100 ml and contact the o-dichlorobenzene solution with 100 ml of aqueous phase. After standing for one day, this aqueous phase contained 0.016M K ⁺ . The solution selectively extracted in this manner can be concentrated to dryness to recover the ions as a solid. Example 7 This example shows the compounds of the present invention as shown in Table 2 above.
This is an example of concentrating K ⁺ ions by taking advantage of the large difference in extraction ability between cis and trans forms for K ⁺ ions. i.e. 0.05M methyl orange and 0.05M
A 100 ml aqueous solution containing KOH was extracted with a 0.1M o-dichlorobenzene solution of the compound of the present invention that had been irradiated with light. When this o-dichlorobenzene solution was brought into contact with 10 ml of water and left for one day, the concentration of K ⁺ in the aqueous phase was 0.15M. As mentioned above, a concentrated aqueous solution of K ⁺ ions could be obtained from a dilute aqueous solution.

[Brief explanation of the drawing]

FIG. 1 shows an ultraviolet spectrum analysis diagram of the biscrown ether derivative of the present invention obtained in Example 1. In the figure, 1 is a measured value in o-dichlorobenzene under dark conditions, 2 is a measured value in o-dichlorobenzene under light irradiation, and 3 is a measured value in a KOH aqueous solution after light irradiation.

Claims (1)

[Claims] 1. General formula A biscrown ether derivative represented by [wherein R ¹ and R ² represent a hydrogen atom or a lower alkyl group, and n represents an integer of 3 to 6]. 2 General formula [In the formula, R ¹ and R ² represent a hydrogen atom or a lower alkyl group, and n represents an integer of 3 to 6] The 4'-nitrobenzo crown ether derivative represented by General formula characterized by reduction [In the formula, R ¹ and R ² represent a hydrogen atom or a lower alkyl group, and n represents an integer of 3 to 6.] A method for producing a biscrown ether derivative represented by the following formula. 3 General formula [In the formula, R ¹ and R ² represent a hydrogen atom or a lower alkyl group, and n represents an integer of 3 to 6.] A selective ion extractant containing a biscrown ether derivative represented by the following formula.