JP3393362B2 - Method for producing organic compound-clay composite - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clay having an organic compound having a specific function and a tetraalkylammonium ion as an interlayer support , a so-called pillared clay (pi).
The present invention relates to a method of forming a stable complex while retaining its function by complexing with the compound of the present invention. [0002] Organic compounds are widely used in various materials including optical functional materials based on their inherent functions. However, in general, organic compounds have low heat resistance and are deteriorated by oxygen in the atmosphere. It has the disadvantage of being easy. For this reason, stabilization is carried out by adsorbing in a porous inorganic substance such as zeolite or enclosing in glass or plastic. However, the adsorption to the porous inorganic substance requires a complicated operation of dissolving the organic compound in an appropriate solvent, impregnating the solution with the porous inorganic substance, and evaporating the solvent. In addition, due to the surface tension of the solvent, it is difficult to penetrate into fine voids to form a uniform composite, and furthermore, there is a drawback that satisfactory stabilization cannot be obtained. On the other hand, in the case of encapsulation in glass or plastic, there is a disadvantage that it is unavoidable to deteriorate by heating, and there has been no known practically satisfactory method. [0003] [0008] The present invention, original function without deteriorating high organophilic of the content of simple organic compounds only are also sufficiently stabilized in the process of organic compounds
The purpose of the present invention is to provide a method for producing a compound- clay composite. The present inventors have conducted various studies on a complex with a layered clay using an organic compound as a guest molecule, and as a result, have first utilized the supercritical state of carbon dioxide. Thus, a complex having both the functionality of the organic compound and the stability of the clay was produced by complexing the organic guest molecule with the layered clay . [0005] However, the composite obtained by such a method has a low content ratio of the organic guest compound, and it is inevitable that the field of use is restricted. Therefore, the present inventors have found that the content of high organic compounds organic guest compound
As a result of further study on the method of obtaining the material-clay complex, carbon dioxide in a supercritical state was used as a medium for introducing an organic guest compound, and as a layered clay , tetraalkylammonium ions were used. clay having become interlayer pillar, by using a so-called Piradokure found that can significantly increase the content of the organic guest compound, leading to completion of the present invention based on this finding. That is, the present invention provides a method of forming a layered clay having an interlayer support composed of tetraalkylammonium ions by immersing the layered clay in an aqueous solution of a tetraalkylammonium salt, and then converting the layered clay into carbon dioxide in a supercritical state. It is contacted with an organic guest compound dissolved in the interlayer
An object of the present invention is to provide a method for producing an organic compound-clay composite , which comprises adsorbing an organic guest compound into a void . Here, the organic guest compound refers to an organic compound having a predetermined function, which is introduced into an interlayer gap of the layered clay. The supercritical carbon dioxide is defined as a critical temperature Tc (31.7 ° C.) and a critical pressure Pc (7.13MP).
a) Carbon dioxide as described above, which has properties intermediate between liquids and gases, namely, density and solubility close to liquids, and viscosity, surface tension, and diffusivity close to gases. DETAILED DESCRIPTION OF THE INVENTION In the present invention, it is necessary to use a clay having an interlayer support as the layered clay . These include, for example, montmorillonite, smectite, hectorite, saponite, vermiculite, talc,
Tetraalkylammonium, which supports interlayer cations of layered clay such as pyrophyllite, hydrite, and mica
It can be obtained by exchanging the beam ions. Among them, those containing tetraalkylammonium ions as pillars are prepared, for example, by immersing a predetermined clay in an aqueous solution of a tetraalkylammonium salt and, if necessary, heating to a temperature of 50 to 90 ° C. After stirring for 1 to 10 hours, the mixture is thoroughly washed with water and dried. [0009] Next, as an organic guest compound to be incorporated into layers of the layered clay, hydrocarbons, amines,
A wide range of compounds such as alcohols, ketones, aldehydes, carboxylic acids, ethers, and nitriles are used, but organic compounds having a specific function, for example, dyes such as 4-phenylazoaniline, rhodamine, spiropyran, and azobenzene Is preferred because the stability can be improved without changing the hue. In the method of the present invention, it is necessary to bring the layered clay into contact with the organic guest compound molecule in the presence of carbon dioxide in a supercritical state. This supercritical state of carbon dioxide is a temperature of 35 to 50 ° C.
Pressure 10 to 20 MPa, preferably temperature 40 to 45 ° C.,
It is brought about by maintaining the pressure at 13-17 MPa. For example, carbon dioxide is introduced into a pressure-resistant closed vessel, and once cooled to liquefy carbon dioxide, the temperature is gradually increased to maintain a temperature of 40 ° C. and a pressure of 14.5 MPa, thereby bringing the supercritical state. The supercritical carbon dioxide thus obtained has fluidity like a gas, density and solubility close to those of a liquid. When the supercritical carbon dioxide comes into contact with the organic guest compound molecules, the organic guest compound molecules dissolve in the supercritical carbon dioxide. And supercritical carbon dioxide
Its low viscosity, low surface tension, the high diffusivity, the layer
These organic guest compound molecules are also carried into the voids as they penetrate into the fine voids having interlayer pillars of the clayey clay . When the pressure is reduced after the organic guest compound molecules have spread to all corners of the void, the density of the supercritical carbon dioxide decreases, and the solubility of the organic guest compound molecules decreases accordingly, and the organic guest compound molecules Precipitates uniformly on each part and is adsorbed. The organic guest compound molecules thus adsorbed are strongly held on the surface of the void. [0012] The ratio of the present invention a method layered clay with an organic guest compound molecule in will depend on the type of the organic guest compound molecules incorporated into it and the kind of layered clay, usually a layered clay, per 100 parts by weight of an organic Guest compound molecules are in the range of 1 to 5 parts by weight. The contact time between the layered clay and the organic guest compound molecule is at least 1 hour, usually in the range of 6 to 24 hours. According to the method of the present invention, an organic guest compound is dissolved in a conventional organic solvent and impregnated into an inorganic carrier, and then the organic solvent is removed to produce a composite.
Organic guest compounds are more evenly dispersed and tightly bound,
A composite having good stability can be produced in a short time without deteriorating the function. In addition, since a layered clay having an interlayer support is used, a composite containing a very large amount of an organic guest compound can be obtained. Next, the present invention will be described in more detail by way of examples. [0015] Reference Example montmorillonite 500mg was suspended tetramethylammonium chloride aqueous solution 100ml of concentration 5 mg / ml, and stirred for 3 h at 70 ° C.. After filtration, the resultant was repeatedly washed with pure water until no chloride ion was detected in the silver nitrate test, and then dried in a vacuum at room temperature for one day to introduce columns between the layers of montmorillonite. [0016] placed to separate the montmorillonite and 4 phenylazoaniline powder having <br/> interlayer pillar consisting of tetramethylammonium ions from Example Reference example during high pressure vessel, the carbon dioxide while cooling the vessel Once gas was introduced, carbon dioxide was once liquefied. Next, the temperature was gradually increased to bring carbon dioxide into a supercritical state at a temperature of 40 ° C. and a pressure of 14.5 MPa. After maintaining this state for 1, 6, and 12 hours, the pressure was gradually lowered to volatilize and remove oxygen dioxide. The montmorillonite having the remaining interlayer support was washed several times with n-hexane to obtain a sample. The amount of nitrogen and the amount of organic carbon in this sample were determined with a TN-TOC analyzer. Table 1 shows the calculated increase in nitrogen (ΔN) and increase in organic carbon (ΔC) due to the supercritical carbon dioxide treatment. Table 1 also shows their ratio (ΔN / ΔC). The amount of increase in nitrogen by the supercritical carbon dioxide treatment is small in one hour, but a clear increase is observed after 6 hours. The ΔN / ΔC ratios at each treatment time were 0.25, 0.23, 0.20, almost equal to the N / C ratio in 4-phenylazoaniline (0.25). That is, by treating with supercritical carbon dioxide,
It can be seen that 4-phenylazoaniline was absorbed by montmorillonite without any chemical change. Correspondingly, the color of the sample changed from gray to reddish brown. FIG. 1 shows an X-ray diffraction pattern of the obtained sample. The diffraction line near 2θ = 6.3 ° corresponds to the interlayer distance of montmorillonite which is a clay mineral having a layered structure. From FIG. 1, the diffraction line near 2θ = 6.3 ° is not much different from that before the treatment when the time of the treatment with the supercritical carbon dioxide is 1 hour, whereas the diffraction line after the treatment for 6 or 12 hours has It can be seen that it is clearly shifted to the lower angle side. That is, the interlayer distance of the montmorillonite is increased by the supercritical carbon dioxide treatment. FIG. 2 shows nitrogen adsorption isotherms of montmorillonite before and after the supercritical carbon dioxide treatment. 50-70 samples before treatment
While the sample has a pore volume of about ml / g, the sample after treatment has a pore volume of 10 ml / g or less. Despite the increase in interlayer distance in X-ray diffraction, the large decrease in pore volume, which indicates voids between layers, indicates that 4-phenylazoaniline was inserted between layers of montmorillonite having interlayer supports. It is shown that. That is, it can be seen that an organic compound-clay composite composed of 4-phenylazoaniline and montmorillonite was obtained by the treatment using supercritical carbon dioxide. The concentration of 4-phenylazoaniline in the medium in the supercritical carbon dioxide treatment for a reaction time of 12 hours was determined from the weight loss of 4-phenylazoaniline before and after the treatment and the volume of the reaction vessel. 33mg / ml
Met. This is considered to be the upper limit of the concentration of 4-phenylazoaniline in the reaction vessel. Comparative Example 1 4-Phenylazoaniline was suspended in ethanol or acetone to a concentration of 1 mg / ml and dissolved in 50 ml, and 100 mg of montmorillonite having an interlayer support used in the example was added. And stir for 12 hours,
After filtration, it was washed several times with n-hexane. Table 1 shows the results obtained by using a TN-TOC analyzer to determine the increase in nitrogen and organic carbon due to this solution treatment. From Table 1, when methanol or acetone is used, the amount of increase in nitrogen and organic carbon by the treatment is very small. The results in Table 1 show that 4-
Considering that the concentration of phenylazoaniline is higher than that in the case of the supercritical carbon dioxide treatment, it indicates that the insertion reaction of the organic guest compound molecule into the montmorillonite by the solution treatment is slow or progresses only partially. [Table 1] COMPARATIVE EXAMPLE 2 Instead of montmorillonite having an interlayer support, a heat-treated montmorillonite was used in the same manner as in Example 1,
The treatment with supercritical carbon dioxide was performed for one hour. As a result of analyzing the nitrogen concentration in the obtained processed sample by TN-TOC,
It was 0.04 mg / g (0.29 × 10 ⁻⁴ mol / g). This indicates that the use of montmorillonite having an interlayer support increases the absorption amount of 4-phenylazoaniline four times or more.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an X-ray diffraction pattern of montmorillonite subjected to supercritical treatment obtained in an example. FIG. 2 is a nitrogen adsorption isotherm before and after supercritical carbon dioxide treatment.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-293315 (JP, A) JP-A-4-74708 (JP, A) Ryo Ishii et al. Intercalation Attempt, The 72nd Annual Meeting of the Chemical Society of Japan-Proceedings of the Lecture I, Japan, March 12, 1997, p. 10 (58) Field surveyed (Int.Cl. ⁷ , DB name) C01B 33/20-33/44 C07B 61/00-63/00

Claims (1)

(57) Claims 1. The layered clay is immersed in an aqueous solution of a tetraalkylammonium salt to form a layered clay having an interlayer support composed of tetraalkylammonium ions.
Then, it is brought into contact with an organic guest compound dissolved in carbon dioxide in a supercritical state to convert the organic guest into a void between the layers.
A method for producing an organic compound-clay composite , which comprises adsorbing a compound.