Method for producing organically modified smectite clay

Abstract

To provide a method for efficiently producing an organically modified smectite-based clay that prevents agglomeration during production, has excellent handling properties, powder properties, and fluidity, and is expected to be used as a carrier, filler, auxiliary agent, etc.SOLUTION: A method for producing an organically modified smectite-based clay is provided, in which ion exchange of smectite-based clay is carried out in a solution containing an organic salt of a cation and an inorganic anion having an alkyl group having 12 or more carbon atoms and at least 5 wt.% of water, then a cake with a water content of 30 wt.% or more is made by a dehydration operation and a washing operation, and then the cake is dried under a condition of 120°C or higher and lower than 200°C.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for producing an organically modified smectite-based clay. More specifically, it relates to a method for producing an organically modified smectite-based clay that is excellent in handling properties, powder characteristics, and fluidity, and is expected to be used in various applications such as catalyst carriers, fillers, and auxiliaries.

Background Art

[0002] Inorganic oxide compounds such as zeolite, silica, alumina, and clay are being studied as catalyst materials by utilizing their large specific surface areas. Among them, smectite-based clay minerals represented by montmorillonite and hectorite have an ion exchange ability with cations, and thus a modification reaction of ion exchange with specific cations is carried out, and studies are being conducted as solid powder catalysts (see, for example, Non-Patent Document 1).

[0003] In addition, when using clay as a catalyst carrier, since its particle size affects the performance, various studies have been conducted as particle size adjustment methods. For example, a pulverization method using a jet mill, a granulation method using a spray dryer, etc. have been proposed (see, for example, Patent Document 1).

Prior Art Documents

Non-Patent Documents

[0004]

Non-Patent Document 1

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Organically modified clay is produced by an ion exchange reaction between smectite clay and organic salts in the presence of a solvent. During the drying process, smectite clay particles may aggregate to form coarse powder. This coarse powder can be several millimeters to tens of millimeters in size. If organically modified smectite clay containing such coarse powder is used as a catalyst support, the catalytic performance will decrease, requiring an additional process to remove or crush the coarse powder.

[0007] Generally, smectite clays modified with organic salts, especially long-chain alkylamine salts, are less prone to agglomeration, and the disintegration process itself is easier compared to inorganically modified smectite clays. However, classification and disintegration processes are still necessary, so there is a need for a method to produce organically modified smectite clay that does not contain agglomerates. [Means for solving the problem]

[0008] As a result of diligent research to solve the above problems, the present inventors have discovered that it is possible to efficiently produce organically modified smectite clay in a powder state with aggregation prevented by drying a wet organically modified smectite clay under specific temperature conditions after ion exchange under specific conditions, and have completed the present invention.

[0009] In other words, the present invention relates to a method for producing organically modified smectite clay, characterized by performing ion exchange of smectite clay in a solution containing an organic salt of a cation having an alkyl group with 12 or more carbon atoms and an inorganic anion, and 5% by weight or more of water, followed by a deliquidation operation and a water washing operation to obtain a cake with a water content of 30% by weight or more, and then drying it under conditions of 120°C to less than 200°C.

[0010] The present invention will be described in detail below. The present invention relates to a method for efficiently producing organically modified smectite clay in powder form with aggregation prevented, and further relates to a method for producing smectite clay by performing ion exchange with a solution containing organic salt and 5% by weight or more of water when organically modifying the smectite clay, followed by deliquidation, washing with water, and drying under conditions of a water content of 30% by weight or more and a temperature of 120°C or higher but less than 200°C.

[0011] In this invention, the smectite-based clay can be any mineral belonging to the category of smectite-based clays, such as montmorillonite, hectorite, beidelite, nontronite, and saponite. Among these, montmorillonite and hectorite are preferred from the viewpoint of ease of availability and ease of use.

[0012] There are no particular restrictions on the particle size and particle size distribution of the smectite clay, but it is preferable that the maximum diameter is 100 μm or less, as this results in superior catalytic performance when used as a catalyst support.

[0013] In the present invention, the organic salt used for ion exchange is an organic salt of a cation having an alkyl group with 12 or more carbon atoms and an inorganic anion. Examples include salts obtained by the reaction of a base having at least one alkyl group with 12 or more carbon atoms with an inorganic acid such as hydrochloric acid, sulfuric acid, nitric acid, or phosphoric acid. More specifically, examples include dodecylamine hydrochloride, tridecylamine hydrochloride, tetradecylamine hydrochloride, octadecylamine hydrochloride, icosylamine hydrochloride, behenylamine hydrochloride, dimethyldodecylamine hydrochloride, dimethyltridecylamine hydrochloride, and dimethyltetradecylamine hydrochloride. Examples include the hydrochlorides of dimethyloctadecylamine hydrochloride, eicosylamine dimethyl hydrochloride, behenyldimethylamine hydrochloride, didodecylamine hydrochloride, dioctadecylamine hydrochloride, dioleylamine hydrochloride, didodecylmethylamine hydrochloride, methyldioctadecylamine hydrochloride, methyldioleylamine hydrochloride, toridodecylamine hydrochloride, trioctadecylamine hydrochloride, trioleylamine hydrochloride, o-hexylaniline hydrochloride, m-hexylaniline hydrochloride, p-hexylaniline hydrochloride, etc., and their sulfates, nitrates, phosphates, etc. Here, when sodium, lithium, etc., located between the cation having an alkyl group with 12 or more carbon atoms undergo ion exchange with the smectite clay layers, it becomes an organically modified smectite clay with a large interlayer distance and strong ionic properties. On the other hand, it has strong water absorption and cohesiveness, making it difficult to produce powdered material. On the other hand, in the case of cations having alkyl groups with fewer than 12 carbon atoms, ion exchange with smectite clay is possible, but because the alkyl chain length is short, it is difficult to increase the interlayer distance, resulting in poor performance as an organically modified smectite clay.

[0014] Furthermore, in the present invention, when ion exchange of smectite clay is performed, the reaction is carried out using a solution containing an organic salt consisting of a cation having an alkyl group having 12 or more carbon atoms and an inorganic anion, and 5% by weight or more of water. Particularly efficient production is possible, so the amount of the organic salt is preferably 20 to 50 parts by weight per 100 parts by weight of smectite clay, the amount of water is preferably 5% to 80% by weight, and more preferably 30% to 80% by weight. Examples of water include tap water, drinking water, distilled water, and ion-exchanged water. As for the solvent constituting the solution, examples of neutral solvents that have high affinity for water and can dissolve the organic salt consisting of a cation having an alkyl group having 12 or more carbon atoms and an inorganic anion can be listed. Specifically, examples include methanol, ethanol, 1-propanol, 2-propanol, formamide, acetamide, acetone, tetrahydrofuran, N,N-dimethylformamide, and dimethyl sulfoxide. Here, if the proportion of water in the solution is less than 5% by weight, the ionization of the organic salt in the solution will be insufficient, resulting in a decrease in the ion exchange reaction rate and lower efficiency.

[0015] The reaction for ion exchange between smectite clay and an organic salt consisting of a cation having 12 or more C12 alkyl groups and an inorganic anion is not particularly limited, except that a solution containing 5% by weight or more of water is used. Smectite clay may be added to a solution of the organic salt consisting of a cation having 12 or more C12 alkyl groups and an inorganic anion, or a solution containing the organic salt may be added to a slurry of smectite clay. Furthermore, the organic salt consisting of a cation having 12 or more C12 alkyl groups and an inorganic anion may be a pre-prepared one, or one prepared by reacting a base having 12 or more C12 alkyl groups with an inorganic acid in an ion-exchange solvent. The temperature can be any temperature as long as the organic salt consisting of a cation having 12 or more C12 alkyl groups and an inorganic anion is completely soluble in the solvent used, and there are no particular restrictions on the reaction time.

[0016] In this invention, after the ion exchange reaction between smectite clay and an organic salt consisting of a cation having an alkyl group with 12 or more carbon atoms and an inorganic anion is completed, the organic solvent is replaced with water by a deliquidation operation and a water washing operation to obtain an organically modified smectite clay cake. The deliquidation operation and water washing operation can be repeated not only once but multiple times. The water used in the water washing operation can be exemplified as described above. The moisture content of the organically modified smectite clay cake varies depending on the type of organically modified smectite clay, the filtration method and time, etc., but in this invention, the organically modified smectite clay cake has a moisture content of 30% by weight or more, and it is preferable that it is 30% by weight or more and 60% by weight or less, as this enables production with excellent drying efficiency. Here, if the moisture content is less than 30% by weight, aggregated clumps of organically modified smectite clay will be generated regardless of the temperature conditions during drying.

[0017] Furthermore, in this invention, the drying of the organically modified smectite clay cake is carried out under conditions of 120°C or higher but less than 200°C. Here, if the temperature is below 120°C, the small amount of water remaining between the clay particles acts as an adhesive, causing aggregation and the formation of clumps. On the other hand, if the temperature is above 200°C, decomposition of the organic matter in the organically modified smectite clay occurs. There are no particular restrictions on the pressure or atmosphere at this time, but in vacuum drying, fine particles of the organically modified smectite clay are carried along with the evaporating water, and there is a risk that the organically modified smectite clay may be scattered inside the dryer or that the vacuum pump may suck in the organically modified smectite clay. Therefore, it is preferable that the pressure be above atmospheric pressure, and more preferably under a small amount of nitrogen flow in order to prevent deterioration due to heating. [Effects of the Invention]

[0018] The present invention makes it possible to efficiently produce organically modified smectite clay, which has excellent handling properties, powder characteristics, and fluidity, and is expected to have various uses as a catalyst carrier, filler, or auxiliary agent. [Examples]

[0019] Examples are given below to explain the present invention in more detail, but the present invention is not limited by these examples.

[0020] In addition, for the particle size measurement in the examples, a laser diffraction / scattering particle size distribution analyzer (manufactured by Microtrac Bels Co., Ltd., trade name MT-3300) was used, and 2-propanol was used as the solvent. Also, the moisture content was measured using an infrared moisture meter (manufactured by Kett Scientific Co., Ltd., trade name FD-610).

[0021] Example 1 60.0 g of water and 47.4 g of industrial alcohol (manufactured by Nippon Alcohol Sales Co., Ltd., trade name Ekinen F-3) were placed in a 200 ml beaker, and 9.0 g (25.4 mmol) of behenyl dimethylamine (manufactured by Lion Specialty Chemicals Co., Ltd., trade name Lipomin DM22D) and 2.7 ml of concentrated hydrochloric acid were added. The mixture was heated with stirring to 60 °C to prepare an organic salt. Here, 20.0 g of synthetic hectorite (manufactured by BYKEMY Japan Co., Ltd., trade name Laponite S482) with a minimum diameter of 1.3 μm, a median diameter of 11.3 μm, and a maximum diameter of 31.1 μm was added, and the mixture was stirred at 150 rpm for 1 hour while maintaining 60 °C to perform ion exchange.

[0022] After filtering this slurry, it was washed twice with 90 ml of water at 60 °C and then filtered again to obtain a cake of organically modified hectorite with a moisture content of 46% by weight. When this cake was placed in a dryer at 160 °C for 2 hours and dried, 27.2 g of organically modified hectorite was obtained. This organically modified hectorite had a minimum diameter of 1.5 μm, a median diameter of 13.4 μm, and a maximum diameter of 44.0 μm, and no aggregates or lumps were observed.

[0023] Example 2 27 g of organically modified hectorite was obtained in the same manner as in Example 1, except that the drying was changed to 120 °C for 4 hours. This organically modified hectorite had a minimum diameter of 1.5 μm, a median diameter of 13.3 μm, and a maximum diameter of 44.0 μm, and no aggregates or lumps were observed.

[0024] Comparative Example 1 Except for changing the drying time to 80°C for 12 hours, 27.4 g of organically modified hectorite was obtained in the same manner as in Example 1. This organically modified hectorite had a minimum diameter of 2.1 μm, a median diameter of 16.8 μm, and a maximum diameter of 124.5 μm, and contained aggregates and lumps, making it unusable as is. Processes such as grinding and classification were necessary.

[0025] Example 3 In a 300 ml beaker, 90.0 g of water and 70.2 g of industrial alcohol were added. 16.1 g (30.0 mmol) of dioleylmethylamine (Lion Specialty Chemicals, product name Lipomin M2O) and 3.2 ml of concentrated hydrochloric acid were added, and the mixture was heated while stirring to 60°C to prepare the organic salt. 30.0 g of hectorite with a minimum diameter of 1.8 μm, a median diameter of 12.6 μm, and a maximum liquid diameter of 31.1 μm was added, and the mixture was stirred at 150 rpm for 1 hour while maintaining the temperature at 60°C to perform ion exchange.

[0026] After filtering the slurry, it was washed twice with 80 ml of 60°C water and filtered again to obtain a cake of organically modified hectorite with a water content of 32% by weight. This cake was dried in a 190°C dryer for 2 hours, yielding 33.1 g of organically modified hectorite. This organically modified hectorite had a minimum diameter of 1.8 μm, a median diameter of 15.6 μm, and a maximum diameter of 52.3 μm, and no aggregates or clumps were observed.

[0027] Comparative Example 2 Except for changing the drying time to 80°C for 12 hours, 27.4 g of organically modified hectorite was obtained in the same manner as in Example 3. This organically modified hectorite had a minimum diameter of 1.5 μm, a median diameter of 16.9 μm, and a maximum diameter of 88.0 μm, and contained aggregates and lumps, making it unusable as is. Processes such as grinding and classification were necessary.

[0028] Comparative Example 3 The organically modified hectorite (water content 1.0% by weight) from Comparative Example 2 was further dried at 160°C for 2 hours, but no changes were observed in particle size or other properties. [Industrial applicability]

[0029] The organically modified smectite clay of the present invention exhibits excellent handling properties, powder characteristics, and fluidity, and is expected to have various uses as a catalyst carrier, filler, and auxiliary agent.

Claims

1. A method for producing organically modified smectite clay, characterized by performing ion exchange of smectite clay in a solution of a neutral solvent containing an organic salt of a cation having at least one alkyl group with 12 or more carbon atoms and an inorganic anion, and 5% to 80% by weight of water, followed by a deliquidation operation and a water washing operation to obtain a cake with a water content of 30% to 60% by weight, and then drying it under conditions of 120°C to less than 200°C.

2. The method for producing organically modified smectite clay according to claim 1, characterized in that the organic salt comprising a cation having at least one alkyl group with 12 or more carbon atoms and an inorganic anion is an alkylamine salt.

3. A method for producing organically modified smectite clay according to claim 1 or 2, characterized in that the smectite clay has a maximum diameter of 100 μm or less.

4. A method for producing organically modified smectite clay according to any one of claims 1 to 3, characterized in that 20 to 50 parts by weight of an organic salt comprising a cation having at least one alkyl group with 12 or more carbon atoms and an inorganic anion are used per 100 parts by weight of smectite clay.