WO2024117263A1 - Ethylene decomposer, freshness preserver, article comprising ethylene decomposer or freshness preserver, and use for same - Google Patents

Ethylene decomposer, freshness preserver, article comprising ethylene decomposer or freshness preserver, and use for same Download PDF

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Publication number
WO2024117263A1
WO2024117263A1 PCT/JP2023/043169 JP2023043169W WO2024117263A1 WO 2024117263 A1 WO2024117263 A1 WO 2024117263A1 JP 2023043169 W JP2023043169 W JP 2023043169W WO 2024117263 A1 WO2024117263 A1 WO 2024117263A1
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alcohol
silica gel
platinum group
ethylene
group element
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PCT/JP2023/043169
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French (fr)
Japanese (ja)
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彩子 寺島
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三菱ケミカル株式会社
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    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23B—PRESERVING, e.g. BY CANNING, MEAT, FISH, EGGS, FRUIT, VEGETABLES, EDIBLE SEEDS; CHEMICAL RIPENING OF FRUIT OR VEGETABLES; THE PRESERVED, RIPENED, OR CANNED PRODUCTS
    • A23B7/00—Preservation or chemical ripening of fruit or vegetables
    • A23B7/14—Preserving or ripening with chemicals not covered by groups A23B7/08 or A23B7/10
    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
    • A23L3/00—Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs
    • A23L3/34—Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs by treatment with chemicals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
    • B01J23/42—Platinum

Definitions

  • the present invention relates to an ethylene decomposition agent, a freshness preservation agent, and an article containing them, as well as the use of the same.
  • Ethylene is a type of plant hormone that has the effect of promoting the ripening of plants.
  • Various methods have been developed and put into practical use to control the concentration of ethylene emitted by plants, including blocking it with films, adsorption, application of ethylene inhibitors, and decomposition by catalysts.
  • Patent Document 1 describes an ethylene decomposition agent in which platinum or a platinum-containing compound is supported on porous silica.
  • the present inventors have found that in the method of Patent Document 1, the ethylene decomposition performance is reduced by moisture. Since the generation of moisture is inevitable during the transportation and storage of plants, the objective of the present invention is to provide an ethylene decomposing agent and a freshness preserving agent whose ethylene decomposition performance is not easily deteriorated even in the presence of moisture, articles containing the agent and the freshness preserving agent, and a method for using the agent and the freshness preserving agent.
  • a freshness-preserving agent for plants comprising silica gel carrying a platinum group element, for use in the presence of alcohol.
  • a freshness-preserving agent for plants comprising platinum group element-supported silica gel and alcohol.
  • the plant freshness-preserving agent according to [10], wherein the platinum group element-supported silica gel and the alcohol are each packed separately.
  • An ethylene decomposition device comprising a platinum group element-supported silica gel and an alcohol generating source.
  • An article comprising an ethylene decomposition agent according to any one of [1] to [6], a plant freshness-preserving agent according to any one of [7] to [12], or an ethylene decomposition device according to any one of [13] to [15].
  • 1 is a graph showing changes in ethylene concentration over time in an ethylene decomposition test of Example 1 and Comparative Example 1.
  • 1 is a graph showing the change in ethylene concentration over time in an ethylene decomposition test of Examples 1-2 and Comparative Example 2.
  • 1 is a graph showing the change in ethylene concentration over time in an ethylene decomposition test of Example 2 and Comparative Example 3.
  • 1 is a graph showing the change in ethylene concentration over time in the ethylene decomposition tests of Example 3 and Comparative Example 4.
  • the ethylene decomposition agent of the present invention is an ethylene decomposition agent which contains a platinum group element-supported silica gel and is used for decomposing ethylene in the coexistence of an alcohol.
  • the ethylene decomposition agent of the present invention may contain both an alcohol and a platinum group element-supported silica gel.
  • the ethylene decomposition agent of the present invention decomposes ethylene, which accelerates the maturation and deterioration of plants, and can therefore also be used as an agent for preserving the freshness of plants.
  • the platinum group element-supported silica gel means a silica gel on which a platinum group element is supported in the form of a metal and/or a compound.
  • the platinum group element may be supported in the form of a particulate material on the surface of the silica gel, or a part of the platinum group element may penetrate into the pore walls of the silica gel.
  • At least a part of the platinum group element may be bonded to the silicon atom of the silica gel directly or via another element, or may be present in a form bound to another element or compound.
  • Platinum group elements are elements located in groups 8 to 10 of the fifth and sixth periods of the periodic table. That is, examples of platinum group elements include platinum, palladium, rhodium, iridium, ruthenium, and osmium.
  • the platinum group element supported on the platinum group element-supported silica gel may be one type or two or more types. Among these, it is preferable that the platinum group element supported on the silica gel is platinum element, in terms of high catalytic activity even at temperatures of 100° C. or less, and the production volume and price of platinum group elements.
  • the platinum group element-supported silica gel according to this embodiment preferably satisfies the following formula (1).
  • A represents the number of platinum group elements supported on the silica gel in the hydroxide state
  • B represents the number of platinum group elements supported on the silica gel in the metallic state.
  • the platinum group element-supported silica gel satisfies formula (1), the ethylene decomposition rate, particularly the ethylene decomposition rate in an atmosphere of 0°C or higher, is improved.
  • the reason for this is not clear, but the following reasons are thought to be possible.
  • the number of platinum elements supported on the silica gel in the metallic state and the proportion of platinum elements supported on the silica gel in the hydroxide state can be determined by measuring the concentrations of platinum alone and platinum hydroxide using X-ray photoelectron spectroscopy (XPS).
  • XPS X-ray photoelectron spectroscopy
  • platinum group elements supported in the metallic state are sometimes referred to as platinum group metals
  • platinum group elements supported in the hydroxide state are sometimes referred to as platinum group element-containing hydroxides.
  • A/(A+B) ⁇ 100 is 10% or more, preferably 15% or more, and more preferably 20% or more.
  • the upper limit is preferably 95% or less.
  • the platinum group element-supported silica gel may support multiple types of platinum group elements. Furthermore, when platinum group metals are also supported on the platinum group element-supported silica gel, the type of platinum group element supported in the metallic state and the type of platinum group element supported in the hydroxide state may be the same or different. However, as described above, it is preferable that the platinum group element is elemental platinum, and in this case, it is particularly preferable that the platinum group elements A and B in formula (1) are elemental platinum and satisfy the above formula (1).
  • the proportion of platinum group elements in 100% by mass of platinum group element-supported silica gel is preferably 0.1% by mass or more, and more preferably 0.5% by mass or more, from the viewpoint of improving ethylene decomposition, while from the viewpoint of durability, it is preferably 5% by mass or less, and more preferably 4% by mass or less.
  • the average particle size of the silica gel is not particularly limited, but in order to suppress particle aggregation, it is preferably 1 ⁇ m or more, more preferably 3 ⁇ m or more, and particularly preferably 5 ⁇ m or more. On the other hand, in order to maintain a certain degree of surface area of the particles, it is preferably 1,000 ⁇ m or less, more preferably 800 ⁇ m or less, and particularly preferably 600 ⁇ m or less.
  • the average particle size of the platinum group element-supported silica gel can be measured as the volume average particle size by a laser diffraction particle size distribution measuring device based on the particle size distribution measuring method described in JIS K 1150 (1994) Silica Gel Test Method.
  • the total pore volume of the silica gel is preferably 0.1 mL/g or more, more preferably 0.2 mL/g or more, and more preferably 0.3 mL/g or more. It is preferably 1.7 mL/g or less, which is feasible for production as a catalyst carrier, more preferably 1.6 mL/g or less, and even more preferably 1.5 mL/g or less.
  • the specific surface area of the silica gel is not particularly limited, but is preferably 80 to 1200 m 2 /g, more preferably 100 to 1100 m 2 /g, and particularly preferably 120 to 1000 m 2 /g.
  • the pore volume and specific surface area values can be determined by the B.E.T. equation using nitrogen gas adsorption and desorption as described in JIS K 1150 (1994) Silica Gel Test Method.
  • the silica gel according to this embodiment preferably has a modal diameter (Dmax) of less than 20 nm on a pore distribution curve calculated by the BJH method described in E. P. Barrett, L. G. Joyner, P. H. Haklenda, J. Am. Chem. Soc., vol. 73, 373 (1951) from an isothermal desorption curve measured by a nitrogen gas adsorption/desorption method, i.e., a plot of differential nitrogen gas adsorption amount ( ⁇ V/ ⁇ (logd); V is the nitrogen gas adsorption volume) against pore diameter d (nm).
  • ⁇ V/ ⁇ (logd) is the nitrogen gas adsorption volume
  • d pore diameter
  • the total volume of pores within ⁇ 20% of the value of the most frequent diameter (Dmax) is preferably 40% or more of the total volume of all pores, and more preferably 50% or more.
  • the total volume of pores within ⁇ 20% of the value of the most frequent diameter (Dmax) is preferably 90% or less of the total pore volume. This means that the diameters of the pores in the platinum group element-supported silica gel of the present invention are uniform for pores near the most frequent diameter (Dmax).
  • the silica gel according to this embodiment preferably has a differential pore volume ⁇ V/ ⁇ (logd) at the most frequent diameter (Dmax) calculated by the BJH method described above of 2 to 20 mL/g, and particularly preferably 3 to 12 mL/g (in the above formula, d is the pore diameter (nm), and V is the nitrogen gas adsorption volume).
  • Silica gels with differential pore volumes ⁇ V/ ⁇ (logd) within the above range can be said to have an extremely large absolute amount of pores aligned near the most frequent diameter (Dmax).
  • the silica gel according to this embodiment has a non-crystalline three-dimensional structure, i.e., no crystalline structure is observed. This means that when the foreign element-supported silica gel of the present invention is analyzed by powder X-ray diffraction, substantially no crystalline peaks are observed. Furthermore, non-crystalline silica gel is extremely superior in productivity compared to crystalline silica gel.
  • the average particle size of the platinum group element-supported silica gel is not particularly limited, but is preferably 1 ⁇ m or more, more preferably 3 ⁇ m or more, in order to suppress particle aggregation. On the other hand, in order to maintain a certain degree of particle surface area, it is preferably 1,000 ⁇ m or less, more preferably 800 ⁇ m or less, and particularly preferably 600 ⁇ m or less.
  • the average particle size of the platinum group element-supported silica gel can be measured as the volume average particle size by a laser diffraction particle size distribution measuring device based on the particle size distribution measuring method described in JIS K 1150 (1994) Silica Gel Test Method.
  • the total pore volume of the platinum group element-supported silica gel is preferably 0.3 mL/g or more, more preferably 0.4 mL/g or more, and even more preferably 0.5 mL/g or more, from the viewpoint of improving the contact efficiency with ethylene. It is preferably 1.6 mL/g or less, which is feasible for production as a catalyst carrier, more preferably 1.5 mL/g or less, and even more preferably 1.3 mL/g or less.
  • the specific surface area of the platinum group element-supported silica gel is not particularly limited, but is preferably 80 to 1200 m 2 /g, more preferably 100 to 1100 m 2 /g, and particularly preferably 120 to 1000 m 2 /g.
  • the pore volume and specific surface area values can be determined by the B.E.T. equation using the nitrogen adsorption isotherm described in JIS K 1150 (1994) Silica Gel Test Method.
  • the platinum group element-supported silica gel according to this embodiment has a pore distribution curve calculated from an isothermal desorption curve measured by a nitrogen gas adsorption/desorption method using the BJH method described in E. P. Barrett, L. G. Joyner, P. H. Haklenda, J. Am. Chem. Soc., vol. 73, 373 (1951), that is, a graph plotting differential nitrogen gas adsorption amount ( ⁇ V/ ⁇ (logd); V is the nitrogen gas adsorption volume) against pore diameter d (nm) preferably having a modal diameter (Dmax) of less than 20 nm, with no particular lower limit, but preferably 2 nm or more.
  • the total volume of pores within ⁇ 20% of the above-mentioned most frequent diameter (Dmax) is preferably 40% or more of the total volume of all pores, and more preferably 50% or more.
  • the total volume of pores within ⁇ 20% of the above-mentioned most frequent diameter (Dmax) is preferably 90% or less of the total pore volume. This means that the pores in the platinum group element-supported silica gel of the present invention have a uniform diameter near the most frequent diameter (Dmax).
  • the platinum group element-supported silica gel according to this embodiment has a non-crystalline three-dimensional structure, i.e., no crystalline structure is observed. This means that when the foreign element-supported silica gel of the present invention is analyzed by X-ray diffraction, substantially no crystalline peaks are observed. In this specification, non-crystalline silica gel is extremely superior in productivity compared to crystalline silica gel.
  • the platinum group element-supported silica gel according to this embodiment per 100 L of space volume subjected to ethylene decomposition treatment. 1 g or more is more preferable, 2 g or more is even more preferable, and 1 g or more is most preferable. From the viewpoint of the cost of the material, 10 g or less is preferable, 8 g or less is more preferable, and 5 g or less is even more preferable.
  • the ethylene decomposition agent of the present invention can contain an amount of platinum group element-supported silica gel appropriately selected from the above range depending on the space volume subjected to treatment.
  • the alcohol in this embodiment is an organic compound having a hydroxyl group.
  • the alcohol may be a monoalcohol, a diol, or a polyhydric alcohol. From the viewpoint of water solubility, alcohols with three or less carbon atoms are preferred. It is presumed that the water solubility allows the alcohol to be effective as an ethylene decomposition agent even under high humidity conditions. From the viewpoint of use near plants, ethanol is most preferred since it is often used as a food or food additive.
  • Any method can be used to make the alcohol coexist as long as the conditions are such that the alcohol reaches the platinum group element-supported silica gel.
  • the alcohol itself may be made to coexist, or it may be generated by a chemical reaction and made to coexist.
  • the presence of alcohol can be confirmed by collecting gas within 30 cm of the platinum group element-supported silica gel and analyzing it by gas chromatography or gas chromatography mass spectrometry.
  • the state of the alcohol may be gas, liquid, or solid. If it is a solid, it is preferable to use an alcohol that sublimates. If the alcohol is a liquid, it may be in the form of a mist or droplets, or may be in a state in which it is impregnated into some medium (sometimes referred to as an "alcohol sustained-release agent" in this specification). From the viewpoint of being able to use a sprayer, it is preferable because it is easy to make the platinum group element-supported silica gel and the alcohol coexist. When impregnating a medium, it may be impregnated into a porous body. From the viewpoint of being able to impart sustained-release properties, silica gel is preferable, and among them, type B silica is particularly preferable from the viewpoint of having a sufficient pore volume.
  • the coexistence may be started at the start of the ethylene decomposition of the present embodiment, or may be started after a predetermined time has elapsed since the start of the decomposition.
  • the alcohol may be made to coexist throughout the entire period of ethylene decomposition, may be made to coexist at the start of ethylene decomposition and then not newly added to be made to coexist therewith, or may be made to coexist by intermittently adding the alcohol during the entire period of ethylene decomposition. Since a simple coexistence form of spraying only at the start of ethylene decomposition can be adopted, the alcohol may be made to coexist only at the start of ethylene decomposition.
  • the coexistence of alcohol is such that, from the viewpoint of exerting the desired effect, the amount of alcohol in the gas within 30 cm from the platinum group element-supported silica gel is preferably 250 ppm or more per 1 g of the platinum group element-supported silica gel, more preferably 300 ppm or more, even more preferably 500 ppm or more, particularly preferably 800 ppm or more, and most preferably 1000 ppm or more.
  • the ethylene decomposition agent of the present invention contains both an alcohol and a platinum group element-supported silica gel, the platinum group element-supported silica gel and the alcohol may be contained in the same package or in separate packages, and preferably each is separately packaged.
  • the platinum group element-supported silica gel may be in the form of a powder, pellet, or tablet and placed in an ethylene and alcohol-permeable packaging material, and the pellet or tablet form may be used as is, or may be held in a cage.
  • the alcohol may be impregnated in some medium (alcohol sustained release agent) and placed in an alcohol-permeable packaging material.
  • the amount of each of the alcohol and the platinum group element-supported silica gel contained in the ethylene decomposition agent of the present invention may be any amount capable of exerting the desired effect in the space subjected to the ethylene decomposition treatment, and the platinum group element-supported silica gel may be contained in an amount appropriately selected from the above range depending on the volume of the space subjected to the treatment.
  • the alcohol may be contained in any amount per gram of the platinum group element-supported silica gel capable of achieving the above-mentioned range of the amount of alcohol in the gas within 30 cm from the platinum group element-supported silica gel.
  • the ethylene decomposition agent of the present invention may contain other components in addition to the platinum group element-supported silica gel used in the presence of alcohol, as long as the desired ethylene decomposition ability is exhibited. Specifically, it may contain a binder used in forming the platinum group element-supported silica gel.
  • Plants that are the subject of freshness preservation in the present invention include plants that deteriorate due to ethylene.
  • Examples of plants include fruits such as apples, cherries, peaches, and blue plums, citrus fruits such as oranges, grapefruits, mandarins, and sudachi, persimmons, figs, strawberries, kiwi fruits, grapes, blueberries, bananas, mangoes, melons, papayas, lychees, apricots, avocados, cantaloupes, guavas, nectarines, pears (Japanese pears, European pears, etc.), and plums; radishes, carrots, burdock, etc.
  • suitable vegetables include root vegetables, sweet potatoes, onions, ginger, taro, Chinese yam, and other earthen vegetables; leafy vegetables such as asparagus, cabbage, lettuce, spinach, Chinese cabbage, cauliflower, broccoli, and bamboo shoots; fruit vegetables such as tomatoes, eggplants, pumpkins, bell peppers, and cucumbers; wild plants such as bracken and fern; fungi such as shiitake mushrooms, king oyster mushrooms, buna-shimeji mushrooms, hon-shimeji mushrooms, enoki mushrooms, and maitake mushrooms; and flowers such as chrysanthemums, roses, lilies, and orchids. Flowers may be in the form of cut flowers, potted plants, or petals. Among these, fruits and leafy vegetables are preferred because they are more susceptible to deterioration by ethylene.
  • the ethylene decomposition agent of the present invention can be used without limitation in any application requiring the decomposition of ethylene.
  • the plant freshness preservation agent can be provided in various articles requiring the preservation of the freshness of plants.
  • Specific examples of articles comprising the ethylene decomposer and plant freshness-preserving agent of the present invention include articles used for storing or transporting plants, such as bags, containers, filters, refrigerators, freezers, containers, air conditioners, vehicles, ships, and aircraft.
  • the ethylene decomposition agent of the present invention may be provided in a reactor as an article.
  • the product include a package of platinum group element-supported silica gel and alcohol, or a device equipped with platinum group element-supported silica gel and an alcohol generating source.
  • the package containing the platinum group element-supported silica gel and the alcohol may be one in which the platinum group element-supported silica gel and the alcohol are separately packaged.
  • the platinum group element-supported silica gel may be in the form of a powder, pellet, or tablet and placed in a packaging material that is permeable to ethylene and alcohol, or the pellet or tablet form may be used as is, or may be held in a cage. From the viewpoint of ease of handling, the alcohol may be used by impregnating a carrier.
  • the device including the platinum group element-supported silica gel and the alcohol generating source may be integrated or separate. If they are separate, there are no limitations on the structure or installation distance as long as the alcohol reaches the platinum group element-supported silica gel.
  • the alcohol source is not structurally limited as long as it has a mechanism for volatilizing, vaporizing, or spraying alcohol.
  • the mechanism for volatilizing alcohol includes a mechanism for holding a carrier impregnated with alcohol.
  • the mechanism for evaporating alcohol includes a heating mechanism and an ultrasonic mechanism.
  • the mechanism for spraying alcohol includes a sprayer including a sprayer. When used as the freshness-preserving device of the present invention, evaporation or spraying is preferred to prevent deterioration due to heating.
  • the ethylene decomposition agent of the present invention can be produced by producing a platinum group element-supported silica gel, and by making an alcohol coexist with the platinum group element-supported silica gel.
  • the method of coexistence is as described above.
  • platinum group element-supported silica gel Although there is no particular limitation on the method for producing the platinum group element-supported silica gel, it can be preferably obtained by reducing a mixture of a platinum group element raw material, such as a platinum-containing compound or an organic complex containing a platinum group element, and silica gel.
  • a platinum group element raw material such as a platinum-containing compound or an organic complex containing a platinum group element
  • silica gel silica gel.
  • the platinum group element-supported silica gel can be obtained by preparing an aqueous solution containing the platinum group element raw material, impregnating silica gel with the solution, drying the solution, and then carrying out a reduction treatment.
  • Examples of compounds containing platinum group elements include hydrochlorides, nitrates, sulfates, etc. of platinum group elements.
  • the BET specific surface area, pore volume, and particle size of the silica gel before the platinum group element is loaded there are no particular limitations on the BET specific surface area, pore volume, and particle size of the silica gel before the platinum group element is loaded, and these may be appropriately selected so as to obtain the desired platinum group element-loaded silica gel. Therefore, the preferred ranges for these are the same as those given above for the platinum group element-loaded silica gel.
  • the method for producing silica gel is not particularly limited, and for example, a method of producing silica gel by washing and drying the silica hydrogel obtained by hydrolyzing an alkali silicate can be used.
  • a representative method includes a method of mixing an alkali silicate with sulfuric acid to obtain silicic acid, maturing the mixture, washing the obtained silicic acid gel to remove impurities such as sodium, and then maturing the silica hydrogel to adjust the specific surface area, pore volume, pore diameter, etc., and then removing the water in the silica hydrogel to obtain silica gel.
  • silica gel can be produced by applying a method in which silica hydrogel obtained by hydrolyzing silicon alkoxide is subjected to hydrothermal treatment without aging.
  • Another method for producing silica gel is to mix and react an inorganic raw material with an organic templating agent to form an organic-inorganic composite in which an inorganic skeleton is formed around the organic templating agent, and then remove the organic material from the composite.
  • the method of hydrolyzing silicon alkoxide is preferable from the viewpoint of producing silica gel containing less impurities such as alkali metals.
  • an alkali metal salt of silicate is used as the silicon alkoxide.
  • the alkali metal sodium or potassium is preferably used.
  • silicon alkoxide examples include tri- or tetraalkoxysilanes having a lower alkyl group with 1 to 4 carbon atoms, such as trimethoxysilane, tetramethoxysilane, triethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane, or oligomers thereof, with tetramethoxysilane, tetraethoxysilane, and tetrapropoxysilane being preferred.
  • tri- or tetraalkoxysilanes having a lower alkyl group with 1 to 4 carbon atoms such as trimethoxysilane, tetramethoxysilane, triethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane, or oligomers thereof, with tetramethoxysilane,
  • the above silicon alkoxides can be easily purified by distillation, and are therefore suitable as raw materials for high-purity silica gel.
  • the total content of metal impurities in silicon alkoxides is usually preferably 100 ppm or less, and more preferably 10 ppm or less.
  • the content of metal impurities can be measured by the same method as that for measuring impurities in silica gel.
  • the hydrolysis of silicon alkoxide is usually carried out using 2 to 20 moles, preferably 3 to 10 moles, and particularly preferably 4 to 8 moles of water per mole of silicon alkoxide.
  • Hydrolysis of silicon alkoxide produces silica hydrogel and alcohol.
  • This hydrolysis reaction is usually carried out at room temperature to about 100°C, but it can also be carried out at higher temperatures by maintaining the liquid phase under pressure.
  • the reaction time depends on the composition of the reaction liquid (type of silicon alkoxide and molar ratio with water) and the reaction temperature, and the time until gelation varies, so it is not generally specified.
  • the reaction time is the time during which the breaking stress of the hydrogel does not exceed 6 MPa.
  • hydrolysis can be promoted by adding acids, alkalis, salts, etc. as catalysts to the reaction system. However, the use of such additives causes the generated hydrogel to mature, as described below, so it is preferable not to use them in the production of silica gel.
  • silicon alkoxide is hydrolyzed to produce silicate, which is then condensed, causing the viscosity of the reaction solution to increase, and finally gelling to form silica hydrogel.
  • silica gel it is preferable to immediately carry out hydrothermal treatment without substantial aging, so that the hardness of the silica hydrogel produced by the hydrolysis does not increase.
  • the above-mentioned hydrothermal treatment of the silica hydrogel produced by hydrolysis immediately without substantial maturation means that the silica hydrogel is subjected to the next hydrothermal treatment while maintaining the soft state it has immediately after production. It is not preferable to add acids, alkalis, salts, etc. to the hydrolysis reaction system of silicon alkoxide, or to make the temperature of the hydrolysis reaction too strict, as these will accelerate the maturation of the hydrogel. In addition, it is preferable not to use more heat or time than necessary in the post-treatments following hydrolysis, such as washing with water, drying, and leaving.
  • the conditions for hydrothermal treatment may be that the water is either liquid or gaseous, and may be diluted with a solvent or other gas, but liquid water is preferably used.
  • liquid water is preferably used to the silica hydrogel, usually 0.1 to 10 times by mass, preferably 0.5 to 5 times by mass, and particularly preferably 1 to 3 times by mass, of water is added to form a slurry, and the treatment is usually carried out at a temperature of 40 to 250°C, preferably 50 to 200°C, for usually 0.1 to 100 hours, preferably 1 to 10 hours.
  • the water used for hydrothermal treatment may contain lower alcohols, methanol, ethanol, propanol, etc. This hydrothermal treatment method is also applicable to materials in which silica gel is formed in the form of a film or layer on a substrate such as particles, substrate, or tube for the purpose of making a membrane reactor, etc.
  • the pore diameter and pore volume of the resulting silica gel tend to increase as the temperature increases.
  • the specific surface area of the resulting silica gel tends to reach a maximum once and then gradually decrease with the treatment time.
  • the temperature and time of the hydrothermal treatment are set outside the above ranges, it becomes difficult to obtain the silica gel of the present invention. For example, if the temperature of the hydrothermal treatment is too high, the pore diameter and pore volume of the silica gel will become too large, and the pore distribution will also become broader. Conversely, if the temperature of the hydrothermal treatment is too low, the silica gel produced will tend to have a low degree of cross-linking and poor thermal stability.
  • the same effect can be obtained at a lower temperature than when it is performed in pure water. Furthermore, when hydrothermal treatment is performed in ammonia water, the final silica gel generally becomes more hydrophobic than when it is treated in pure water, but when hydrothermal treatment is performed at a relatively high temperature, usually 30 to 250°C, preferably 40 to 200°C, the hydrophobicity becomes particularly high.
  • the ammonia concentration of the ammonia water here is preferably 0.001 to 10%, and particularly preferably 0.005 to 5%.
  • the hydrothermally treated silica hydrogel is usually dried at 40 to 200°C, preferably 60 to 120°C. There are no particular limitations on the drying method, and it can be either batch or continuous, and can be dried at normal pressure or reduced pressure. If carbon derived from the silicon alkoxide raw material is present as needed, it can be removed by baking, usually at 400 to 600°C. To control the surface condition, it may also be baked at a maximum temperature of 900°C. Furthermore, it may be crushed and classified as needed.
  • the inorganic raw material may be an alkoxysilane such as tetramethoxysilane, tetraethoxysilane, or tetrapropoxysilane, sodium silicate, kanemite (NaHSi 2 O 5.3H 2 O), silica, or a silica-metal composite oxide, etc. These may be used alone or in combination of two or more kinds.
  • the organic compound used as the organic template agent is not particularly limited, but examples thereof include surfactants.
  • the surfactant may be cationic, anionic, or nonionic. Specific examples include chlorides, bromides, iodides, or hydroxides of alkyltrimethylammonium (preferably alkyltrimethylammonium with an alkyl group having 8 to 18 carbon atoms), alkylammonium, dialkyldimethylammonium, and benzylammonium, as well as fatty acid salts, alkylsulfonates, alkylphosphates, polyethylene oxide-based nonionic surfactants, primary alkylamines, triblock copolymer-type polyalkylene oxides, glycerin fatty acid esters, and polyglycerin fatty acid esters. These may be used alone or in combination of two or more.
  • a suitable solvent can be used.
  • the solvent includes water, an organic solvent, and a mixture of water and an organic solvent.
  • the method for forming a composite of inorganic and organic substances is not particularly limited, but an example is a method in which an organic templating agent is dissolved in a solvent, inorganic raw materials are added, the pH is adjusted to a specified value, and the reaction mixture is then maintained at a specified temperature to carry out a condensation polymerization reaction.
  • the reaction temperature for the condensation polymerization reaction varies depending on the type and concentration of the organic templating agent and inorganic raw materials used, but is usually preferably around 0 to 100°C, and more preferably 35 to 80°C.
  • the reaction time for the condensation polymerization reaction is usually preferably about 1 to 24 hours.
  • the condensation polymerization reaction may be carried out either in a stationary state or in a stirred state, or in a combination of these.
  • Silica gel is obtained by removing the organic matter from the complex obtained after the condensation polymerization reaction.
  • the organic matter can be removed from the complex of organic and inorganic matter by baking at 400 to 800°C or by treating with a solvent such as water or alcohol.
  • Silica gel that does not have a crystalline structure tends to have high thermal stability in water. If hydrolysis is performed under conditions in which an organic templating agent such as a surfactant is not present in an amount sufficient to function as an organic templating agent, it is unlikely to have a crystalline structure. Furthermore, if an organic templating agent is not used, high-temperature baking to remove the organic templating agent is not required, and the amount of internal silanol groups can be increased, so it is preferable to perform hydrolysis under conditions in which no organic templating agent is used.
  • an organic templating agent such as a surfactant
  • the ethylene decomposition method of the present invention is carried out in the coexistence of a platinum group element-supported silica gel and an alcohol, as described above.
  • the ethylene decomposition method of the present invention can be used as a method for preserving the freshness of a plant when ethylene and the plant are present. That is, in the ethylene decomposition method of the present invention, by preserving the plant in the coexistence of platinum group element-supported silica gel and alcohol, ethylene is decomposed to prevent deterioration of the plant and preserve the freshness of the plant.
  • the method for decomposing ethylene or the method for preserving the freshness of a plant of the present invention can be carried out, for example, by using an article provided with the ethylene decomposing agent or the freshness preserving agent of the present invention.
  • ethylene can be decomposed into carbon dioxide and water in the presence of oxygen.
  • the ethylene decomposition method of the present invention can be carried out at -40°C or higher. From the viewpoint of preventing the plant from freezing, -4°C or higher is more preferable, and 0°C or higher is even more preferable. From the viewpoint of storing the plant, 40°C or lower is preferable, 30°C or lower is more preferable, 20°C or lower is even more preferable, and 15°C or lower is particularly preferable.
  • the ethylene decomposition method of the present invention can be carried out under conditions of moisture of 60 mg/L (ppm) or more, which was previously difficult to apply, by allowing platinum group element-supported silica gel and alcohol to coexist.
  • the moisture content may be 70 ppm or more, or 80 ppm or more. From the perspective of typical storage conditions for plants, 100,000 ppm or less is preferable, 80,000 ppm or less is more preferable, and 75,000 ppm or less is preferable.
  • the moisture content may be 80 ppm or more, or 85 ppm or more, at ⁇ 40° C. There is no particular upper limit, but it may be 188 ppm or less, or 185 ppm or less.
  • the moisture content may be 1000 ppm or more, or 1500 ppm or more.
  • the moisture content may be 4600 ppm or less, or 4500 ppm or less.
  • the moisture content may be 2000 ppm or more, or 3000 ppm or more.
  • the moisture content may be 6100 ppm or less, or 6000 ppm or less.
  • the moisture content When the temperature is 15° C., the moisture content may be 5000 ppm or more, or 6000 ppm or more. There is no particular upper limit, but the moisture content may be 17200 ppm or less, or 17100 ppm or less.
  • the moisture content When the temperature is 20° C., the moisture content may be 10,000 ppm or more, or 15,000 ppm or more. There is no particular upper limit, but the moisture content may be 25,000 ppm or less, or 23,000 ppm or less.
  • the moisture content When the temperature is 30° C., the moisture content may be 20,000 ppm or more, or 22,000 ppm or more. There is no particular upper limit, but the moisture content may be 44,000 ppm or less, or 43,000 ppm or less.
  • the moisture content When the temperature is 40° C., the moisture content may be 35,000 ppm or more, or 40,000 ppm or more. There is no particular upper limit, but the moisture content may be 75,000 ppm or less, or
  • the moisture content may be 75% or more, or 90% or more, in terms of relative humidity.
  • the amount of alcohol in the gas within 30 cm from the platinum group element-supported silica gel is preferably 250 ppm or more per gram of the platinum group element-supported silica gel from the viewpoint of exerting the intended effect. More preferably, it is 300 ppm or more, even more preferably, it is 500 ppm or more, particularly preferably, it is 800 ppm or more, and most preferably, it is 1000 ppm or more.
  • the platinum group element-supported silica gel is preferably used in an amount of 0.5 g or more per 100 L of space volume containing ethylene, more preferably 1 g or more, even more preferably 2 g or more, and most preferably 1 g or more. From the viewpoint of the cost of the material, the amount is preferably 10 g or less, more preferably 8 g or less, and even more preferably 5 g or less.
  • silica hydrogel a powdered wet gel (silica hydrogel).
  • 450g of this silica hydrogel and 450g of pure water were charged into a 1L glass autoclave and subjected to hydrothermal treatment at 130°C for 3 hours. After the hydrothermal treatment, No. The mixture was filtered through No. 5A filter paper, and the filter cake was dried under reduced pressure at 100°C until a constant weight was obtained without washing with water, to obtain Silica Gel A.
  • the pore volume, BET specific surface area, and average pore diameter of Silica Gel A were measured by the following methods. The obtained results are shown in Table 1.
  • the aqueous sulfuric acid solution was placed in a glass beaker, and the platinum group element-supported silica gel A was placed in a petri dish, with the tops of both containers open.
  • the ethylene concentrations after 0.25, 1, 2, 3, 4, 5, 6, and 24 hours were measured using a sensor gas chromatograph (Nissha FIS Co., Ltd., model number: SGEA-P3-C1).
  • the above aqueous sulfuric acid solution was used to maintain a relative humidity of 85%. The results are shown in FIG.
  • Example 1-2> (Ethylene decomposition test) Except for the measurement of the ethylene concentration by gas chromatography, the test was carried out in the same manner as in Example 1. The obtained results are shown in Figure 2 and Table 3. Note that the ethylene concentration after 6 hours was not measured.
  • Example 2 (Ethylene decomposition test) The test was carried out in the same manner as in Example 1-2, except that FT-eco catalyst manufactured by Furuya Metal Co., Ltd. was used instead of platinum group element-supported silica gel A. The obtained results are shown in FIG. 3 and Table 3.
  • the FT-eco catalyst is a platinum group element-supported silica gel.
  • Example 3 (Ethylene decomposition test) The test was carried out in the same manner as in Example 1-2, except that platinum group element-supported silica gel B was used instead of platinum group element-supported silica gel A. The obtained results are shown in FIG.
  • the ethylene decomposing agent, freshness preserving agent, and article comprising them, as well as use of the same, of the present invention are suitably used for decomposing ethylene released from plants, and can maintain the freshness of the plants.

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Abstract

The present invention provides: an ethylene decomposer and a freshness preserver which are not susceptible to a decrease in ethylene decomposition performance even in the presence of moisture; an article comprising the ethylene decomposer or freshness preserver; and a use for the article. Specifically provided are: an ethylene decomposer and a freshness preserver, each of which comprises a platinum group element-loaded silica gel and an alcohol; an article comprising the ethylene decomposer or freshness preserver; and a use for this article.

Description

エチレン分解剤、鮮度保持剤、及びそれらを備えた物品、並びにその利用Ethylene decomposition agent, freshness preservation agent, and article equipped with them, and use thereof
　本発明は、エチレン分解剤、鮮度保持剤、及びそれらを備えた物品、並びにその利用に関する。 The present invention relates to an ethylene decomposition agent, a freshness preservation agent, and an article containing them, as well as the use of the same.
　野菜や果物、生花などを含む植物の流通においては、収穫後の鮮度を可能な限り維持することで、植物の利用可能期間を長くすることができれば、食品ロスや廃棄物の低減や流通範囲の拡大の観点で望ましい。
　植物の鮮度に影響する因子には、温度、湿度、微生物、光、酸素、酵素などが挙げられるが、その他の因子としてよく知られているのが、エチレンである。エチレンは、植物ホルモンの一種で、植物の熟成を促進させる効果がある。
　植物から発生したエチレンの濃度が上昇しないように制御する方法としては、フィルムによる遮断、吸着、エチレン阻害剤の施用、触媒による分解などの各種の方法が開発され、実用化されている。 In the distribution of plants, including vegetables, fruits, and flowers, it would be desirable to extend the usable period of plants by maintaining their freshness as much as possible after harvest, in order to reduce food loss and waste and expand the range of distribution.
Factors that affect the freshness of plants include temperature, humidity, microorganisms, light, oxygen, and enzymes, but another well-known factor is ethylene. Ethylene is a type of plant hormone that has the effect of promoting the ripening of plants.
Various methods have been developed and put into practical use to control the concentration of ethylene emitted by plants, including blocking it with films, adsorption, application of ethylene inhibitors, and decomposition by catalysts.
　特許文献１には、多孔質シリカに白金又は白金含有化合物を担持させてなるエチレン分解剤について記載されている。 Patent Document 1 describes an ethylene decomposition agent in which platinum or a platinum-containing compound is supported on porous silica.
特開２０１７－０２３８８９号公報JP 2017-023889 A
　しかしながら、特許文献１の方法では、水分によりエチレン分解性能が低下することを、本発明者らは見出した。
　植物の移送、保存においては、水分の発生は不可避であることから、水分が存在してもエチレン分解性能が低下しにくいエチレン分解剤、鮮度保持剤、及びそれらを備えた物品、並びにその利用方法を提供することを課題とする。 However, the present inventors have found that in the method of Patent Document 1, the ethylene decomposition performance is reduced by moisture.
Since the generation of moisture is inevitable during the transportation and storage of plants, the objective of the present invention is to provide an ethylene decomposing agent and a freshness preserving agent whose ethylene decomposition performance is not easily deteriorated even in the presence of moisture, articles containing the agent and the freshness preserving agent, and a method for using the agent and the freshness preserving agent.
［１］白金族元素担持シリカゲルを含み、アルコール共存条件下でエチレンを分解するための、エチレン分解剤。
［２］前記アルコールがアルコール徐放剤から放出される、［１］に記載のエチレン分解剤。
［３］前記アルコールが液体または気体である、［１］又は［２］に記載のエチレン分解剤。
［４］　白金族元素担持シリカゲルとアルコールとを含む、エチレン分解剤。
［５］　白金族元素担持シリカゲルとアルコールとがそれぞれ別個に分包されている、［４］に記載のエチレン分解剤。
［６］　アルコールがアルコール徐放剤を含む、［４］又は［５］に記載のエチレン分解剤。
［７］白金族元素担持シリカゲルを含み、アルコール共存条件下で用いる、植物の鮮度保持剤。
［８］前記アルコールがアルコール徐放剤から放出される、［７］に記載の植物の鮮度保持剤。
［９］前記アルコールが液体または気体である、［７］又は［８］に記載の植物の鮮度保持剤。
［１０］白金族元素担持シリカゲルとアルコールとを含む、植物の鮮度保持剤。
［１１］　白金族元素担持シリカゲルとアルコールとがそれぞれ別個に分包されている、［１０］に記載の植物の鮮度保持剤。
［１２］　アルコールがアルコール徐放剤を含む、［１０］又は［１１］に記載の植物の鮮度保持剤。
［１３］白金族元素担持シリカゲルとアルコール発生源を含むエチレン分解デバイス。
［１４］前記アルコール発生源がアルコール徐放剤を含む、［１３］に記載のエチレン分解デバイス。
［１５］前記アルコール発生源が噴霧器である、［１３］に記載のエチレン分解デバイス。
［１６］白金族元素担持シリカゲルと、アルコールを共存させるエチレン分解方法。
［１７］［１］～［６］のいずれかに記載のエチレン分解剤、［７］～［１２］のいずれかに記載の植物の鮮度保持剤、又は［１３］～［１５］のいずれかに記載のエチレン分解デバイスを備える、物品。
［１８］袋、容器、フィルター、冷蔵庫、冷凍庫、コンテナ、空調機、車両、船舶、又は航空機である、［１７］に記載の物品。
［１９］白金族元素担持シリカゲルとアルコールの共存条件下に、植物を保存することを含む、植物の鮮度保持方法。
　本明細書は本願の優先権の基礎である２０２２年１２月１日に出願された日本国特許出願２０２２－１９３１１８号の明細書等に記載される内容を包含する。
　本明細書で引用した全ての刊行物、特許および特許出願をそのまま参考として本明細書にとりいれるものとする。 [1] An ethylene decomposition agent comprising a platinum group element-supported silica gel, for decomposing ethylene in the presence of alcohol.
[2] The ethylene decomposition agent according to [1], wherein the alcohol is released from an alcohol sustained-release agent.
[3] The ethylene decomposition agent according to [1] or [2], wherein the alcohol is a liquid or a gas.
[4] An ethylene decomposition agent comprising a platinum group element-supported silica gel and an alcohol.
[5] The ethylene decomposition agent according to [4], in which the platinum group element-supported silica gel and the alcohol are each packed separately.
[6] The ethylene decomposition agent according to [4] or [5], wherein the alcohol contains an alcohol sustained-release agent.
[7] A freshness-preserving agent for plants, comprising silica gel carrying a platinum group element, for use in the presence of alcohol.
[8] The plant freshness-preserving agent described in [7], wherein the alcohol is released from an alcohol-release agent.
[9] The plant freshness-preserving agent according to [7] or [8], wherein the alcohol is liquid or gaseous.
[10] A freshness-preserving agent for plants, comprising platinum group element-supported silica gel and alcohol.
[11] The plant freshness-preserving agent according to [10], wherein the platinum group element-supported silica gel and the alcohol are each packed separately.
[12] The plant freshness-preserving agent according to [10] or [11], wherein the alcohol contains an alcohol sustained-release agent.
[13] An ethylene decomposition device comprising a platinum group element-supported silica gel and an alcohol generating source.
[14] The ethylene decomposition device described in [13], wherein the alcohol generation source includes an alcohol sustained-release agent.
[15] The ethylene decomposition device described in [13], wherein the alcohol generation source is a sprayer.
[16] A method for decomposing ethylene in the coexistence of a platinum group element-supported silica gel and an alcohol.
[17] An article comprising an ethylene decomposition agent according to any one of [1] to [6], a plant freshness-preserving agent according to any one of [7] to [12], or an ethylene decomposition device according to any one of [13] to [15].
[18] The article according to [17], which is a bag, a container, a filter, a refrigerator, a freezer, a container, an air conditioner, a vehicle, a ship, or an aircraft.
[19] A method for preserving the freshness of a plant, comprising storing the plant in the presence of platinum group element-supported silica gel and alcohol.
This specification includes the contents described in the specification of Japanese Patent Application No. 2022-193118, filed on December 1, 2022, which is the priority basis of this application.
All publications, patents, and patent applications cited herein are hereby incorporated by reference in their entirety.
　水分が存在してもエチレン分解性能が低下しにくいエチレン分解剤、鮮度保持剤、及びそれらを備えた物品、並びにその利用方法を提供する。 To provide an ethylene decomposition agent and freshness preservation agent whose ethylene decomposition performance is not easily deteriorated even in the presence of moisture, as well as articles containing them and methods of using them.
実施例１、及び比較例１のエチレン分解試験における、エチレン濃度の経時変化を示すグラフである。1 is a graph showing changes in ethylene concentration over time in an ethylene decomposition test of Example 1 and Comparative Example 1. 実施例１－２、及び比較例２のエチレン分解試験における、エチレン濃度の経時変化を示すグラフである。1 is a graph showing the change in ethylene concentration over time in an ethylene decomposition test of Examples 1-2 and Comparative Example 2. 実施例２、及び比較例３のエチレン分解試験における、エチレン濃度の経時変化を示すグラフである。1 is a graph showing the change in ethylene concentration over time in an ethylene decomposition test of Example 2 and Comparative Example 3. 実施例３、及び比較例４のエチレン分解試験における、エチレン濃度の経時変化を示すグラフである。1 is a graph showing the change in ethylene concentration over time in the ethylene decomposition tests of Example 3 and Comparative Example 4.
　以下、本発明について、詳細に説明するが、本発明は具体的な実施態様のみに限定されるものではない。 The present invention will be described in detail below, but the present invention is not limited to the specific embodiments.
＜エチレン分解剤＞
　本発明のエチレン分解剤は、白金族元素担持シリカゲルを含み、アルコール共存下でエチレンを分解するために用いられるエチレン分解剤である。本発明のエチレン分解剤は、アルコールと白金族元素担持シリカゲルの両者を含むものとしてもよい。
　本発明のエチレン分解剤は、植物の成熟と劣化を促進するエチレンを分解するため、植物の鮮度保持剤としても用いることができる。 <Ethylene decomposition agent>
The ethylene decomposition agent of the present invention is an ethylene decomposition agent which contains a platinum group element-supported silica gel and is used for decomposing ethylene in the coexistence of an alcohol. The ethylene decomposition agent of the present invention may contain both an alcohol and a platinum group element-supported silica gel.
The ethylene decomposition agent of the present invention decomposes ethylene, which accelerates the maturation and deterioration of plants, and can therefore also be used as an agent for preserving the freshness of plants.
［白金族元素担持シリカゲル］
　本発明において、白金族元素担持シリカゲルとは、金属及び／又は化合物の状態で白金族元素が担持されたシリカゲルを意味するものとする。なお、白金族元素は、シリカゲル表面に粒状物の状態で保持されていてもよいし、一部がシリカゲルの細孔壁内に浸透していてもよい。また、白金族元素の少なくとも一部が、直接又は他の元素を介してシリカゲルの珪素原子と結合していてもよいし、他の元素や化合物と結びついた形で存在していてもよい。 [Platinum group element-supported silica gel]
In the present invention, the platinum group element-supported silica gel means a silica gel on which a platinum group element is supported in the form of a metal and/or a compound. The platinum group element may be supported in the form of a particulate material on the surface of the silica gel, or a part of the platinum group element may penetrate into the pore walls of the silica gel. At least a part of the platinum group element may be bonded to the silicon atom of the silica gel directly or via another element, or may be present in a form bound to another element or compound.
＜白金族元素＞
　白金族元素とは、周期表において第５及び第６周期の第８～１０族に位置する元素である。すなわち、白金族元素とは、白金、パラジウム、ロジウム、イリジウム、ルテニウム、又はオスミウムが挙げられる。なお、白金族元素担持シリカゲルが担持する白金族元素は１種であってもよいし、２種以上であってもよい。これらのなかでも、１００℃以下の温度でも触媒活性が高い点や、白金族元素の産出量および価格の観点で、シリカゲルが担持する白金族元素は白金元素であることが好ましい。 <Platinum group elements>
Platinum group elements are elements located in groups 8 to 10 of the fifth and sixth periods of the periodic table. That is, examples of platinum group elements include platinum, palladium, rhodium, iridium, ruthenium, and osmium. The platinum group element supported on the platinum group element-supported silica gel may be one type or two or more types. Among these, it is preferable that the platinum group element supported on the silica gel is platinum element, in terms of high catalytic activity even at temperatures of 100° C. or less, and the production volume and price of platinum group elements.
　本実施形態に係る白金族元素担持シリカゲルは、下記式（１）を満たすことが好ましい。 The platinum group element-supported silica gel according to this embodiment preferably satisfies the following formula (1).
　Ａ／（Ａ＋Ｂ）×１００≧１０％・・・式（１） 　A/(A+B)×100≧10%・・・Formula (1)
　式（１）中、Ａは水酸化物の状態でシリカゲルに担持された白金族元素の数を表し、Ｂは金属の状態でシリカゲルに担持された白金族元素の数を表す。 In formula (1), A represents the number of platinum group elements supported on the silica gel in the hydroxide state, and B represents the number of platinum group elements supported on the silica gel in the metallic state.
　白金族元素担持シリカゲルが式（１）を満たすことにより、エチレン分解速度、特に、０℃以上の雰囲気下でのエチレンの分解速度が向上する。この理由は明らかではないが、下記の理由が考えられる。 When the platinum group element-supported silica gel satisfies formula (1), the ethylene decomposition rate, particularly the ethylene decomposition rate in an atmosphere of 0°C or higher, is improved. The reason for this is not clear, but the following reasons are thought to be possible.
　エチレンの酸化反応では白金表面でエチレンが酸化され、ヒドロキシ基が一酸化炭素および酸素を逐次的に活性化している。そのため、白金族元素担持シリカゲルにおいて水酸化物の状態で存在する白金族元素の割合が１０％以上となることにより、酸化反応がより有利に進むと考えられる。 In the oxidation reaction of ethylene, ethylene is oxidized on the platinum surface, and the hydroxyl groups successively activate carbon monoxide and oxygen. Therefore, it is believed that the oxidation reaction proceeds more favorably when the proportion of platinum group elements present in the hydroxide state in the platinum group element-supported silica gel is 10% or more.
　なお、金属の状態でシリカゲルに担持された白金元素の数及び水酸化物の状態でシリカゲルに担持された白金元素の割合は、白金単体及び水酸化白金の濃度をＸ線光電子分光法（ＸＰＳ）により測定することができる。また、本発明において、金属の状態で担持された白金族元素を白金族金属と称し、水酸化物の状態で担持された白金族元素を白金族元素含有水酸化物と称す場合もある。 The number of platinum elements supported on the silica gel in the metallic state and the proportion of platinum elements supported on the silica gel in the hydroxide state can be determined by measuring the concentrations of platinum alone and platinum hydroxide using X-ray photoelectron spectroscopy (XPS). In the present invention, platinum group elements supported in the metallic state are sometimes referred to as platinum group metals, and platinum group elements supported in the hydroxide state are sometimes referred to as platinum group element-containing hydroxides.
　上記式（１）の通り、Ａ／（Ａ＋Ｂ）×１００は１０％以上であるが、なかでも、１５％以上であることが好ましく、２０％以上であることがさらに好ましい。また、上限としては９５％以下が好ましい。 As shown in formula (1) above, A/(A+B)×100 is 10% or more, preferably 15% or more, and more preferably 20% or more. The upper limit is preferably 95% or less.
　また、白金族元素担持シリカゲルは複数種の白金族元素が担持されていてもよい。さらに、白金族元素担持シリカゲルに白金族金属も担持されている場合、金属の状態で担持される白金族元素と、水酸化物の状態で担持される白金族元素の種類は同じであってもよいし、異なっていてもよい。しかしながら、上述の通り白金族元素は白金元素であることが好ましく、この場合、式（１）中のＡ及びＢの白金族元素は白金元素として、上記式（１）を満たすことが特に好ましい。 The platinum group element-supported silica gel may support multiple types of platinum group elements. Furthermore, when platinum group metals are also supported on the platinum group element-supported silica gel, the type of platinum group element supported in the metallic state and the type of platinum group element supported in the hydroxide state may be the same or different. However, as described above, it is preferable that the platinum group element is elemental platinum, and in this case, it is particularly preferable that the platinum group elements A and B in formula (1) are elemental platinum and satisfy the above formula (1).
　白金族元素担持シリカゲル１００質量％における白金族元素の割合は、エチレン分解向上の観点から、０．１質量％以上であることが好ましく、０．５質量％以上であることがさらに好ましく、一方、耐久性の観点から、５質量％以下であることが好ましく、４質量％以下であることがさらに好ましい。 The proportion of platinum group elements in 100% by mass of platinum group element-supported silica gel is preferably 0.1% by mass or more, and more preferably 0.5% by mass or more, from the viewpoint of improving ethylene decomposition, while from the viewpoint of durability, it is preferably 5% by mass or less, and more preferably 4% by mass or less.
＜シリカゲル＞
　シリカゲルの平均粒子径は特段の制限はないが、粒子の凝集を抑制するために、１μｍ以上であることが好ましく、３μｍ以上であることがさらに好ましく、５μｍ以上であることが特に好ましい。一方、粒子の表面積をある程度保つために１，０００μｍ以下であることが好ましく、８００μｍ以下であることがさらに好ましく、６００μｍ以下であることが特に好ましい。なお、白金族元素担持シリカゲルの平均粒子径は、ＪＩＳ　Ｋ　１１５０　（１９９４）　シリカゲル試験方法に記載の粒度分布測定方法に基づいて、レーザー回折式粒度分布測定装置計により、体積平均粒子径として測定することができる。 <Silica gel>
The average particle size of the silica gel is not particularly limited, but in order to suppress particle aggregation, it is preferably 1 μm or more, more preferably 3 μm or more, and particularly preferably 5 μm or more. On the other hand, in order to maintain a certain degree of surface area of the particles, it is preferably 1,000 μm or less, more preferably 800 μm or less, and particularly preferably 600 μm or less. The average particle size of the platinum group element-supported silica gel can be measured as the volume average particle size by a laser diffraction particle size distribution measuring device based on the particle size distribution measuring method described in JIS K 1150 (1994) Silica Gel Test Method.
　シリカゲルの全細孔容積は、エチレンとの接触効率向上の観点から、０．１ｍＬ／ｇ以上が好ましく、０．２ｍＬ／ｇ以上が好ましく、０．３ｍＬ／ｇ以上が好ましい。触媒担体として製造が実現可能な１．７ｍＬ／ｇ以下が好ましく、１．６ｍＬ／ｇ以下がより好ましく、１．５ｍＬ／ｇ以下がさらに好ましい。 From the viewpoint of improving the contact efficiency with ethylene, the total pore volume of the silica gel is preferably 0.1 mL/g or more, more preferably 0.2 mL/g or more, and more preferably 0.3 mL/g or more. It is preferably 1.7 mL/g or less, which is feasible for production as a catalyst carrier, more preferably 1.6 mL/g or less, and even more preferably 1.5 mL/g or less.
　また、シリカゲルの比表面積は、特段の制限はないが、８０～１２００ｍ２／ｇであることが好ましく、１００～１１００ｍ２／ｇであることがさらに好ましく、１２０～１０００ｍ２／ｇであることが特に好ましい。なお、これらの細孔容積及び比表面積の値は、ＪＩＳ　Ｋ　１１５０　（１９９４）　シリカゲル試験方法に記載の窒素ガス吸脱着によるＢ．Ｅ．Ｔ．式で求めることができる。 The specific surface area of the silica gel is not particularly limited, but is preferably 80 to 1200 m 2 /g, more preferably 100 to 1100 m 2 /g, and particularly preferably 120 to 1000 m 2 /g. The pore volume and specific surface area values can be determined by the B.E.T. equation using nitrogen gas adsorption and desorption as described in JIS K 1150 (1994) Silica Gel Test Method.
　本実施形態に係るシリカゲルは、窒素ガス吸脱着法で測定した等温脱着曲線から、Ｅ．　Ｐ．　Ｂａｒｒｅｔｔ，　Ｌ．　Ｇ．　Ｊｏｙｎｅｒ，　Ｐ．　Ｈ．　Ｈａｋｌｅｎｄａ，　Ｊ．　Ａｍ．　Ｃｈｅｍ．　Ｓｏｃ．，　ｖｏｌ．　７３，　３７３　（１９５１）に記載のＢＪＨ法により算出される細孔分布曲線、即ち、細孔直径ｄ（ｎｍ）に対して微分窒素ガス吸着量（ΔＶ／Δ（ｌｏｇｄ）；Ｖは窒素ガス吸着容積）をプロットした図上での最頻直径（Ｄｍａｘ）が２０ｎｍ未満であることが好ましく、下限は特に制限はないが、好ましくは２ｎｍ以上である。 The silica gel according to this embodiment preferably has a modal diameter (Dmax) of less than 20 nm on a pore distribution curve calculated by the BJH method described in E. P. Barrett, L. G. Joyner, P. H. Haklenda, J. Am. Chem. Soc., vol. 73, 373 (1951) from an isothermal desorption curve measured by a nitrogen gas adsorption/desorption method, i.e., a plot of differential nitrogen gas adsorption amount (ΔV/Δ(logd); V is the nitrogen gas adsorption volume) against pore diameter d (nm). There is no particular lower limit, but it is preferably 2 nm or more.
　本実施形態に係るシリカゲルは、上記の最頻直径（Ｄｍａｘ）の値の±２０％の範囲にある細孔の総容積が、全細孔の総容積の４０％以上であることが好ましく、５０％以上であることがさらに好ましい。また、上記の最頻直径（Ｄｍａｘ）の値を中心として±２０％の範囲にある細孔の総容積は、全細孔容積の９０％以下であることが好ましい。このことは、本発明の白金族元素担持シリカゲルが有する細孔の直径が、最頻直径（Ｄｍａｘ）付近の細孔で揃っていることを意味する。 In the silica gel according to this embodiment, the total volume of pores within ±20% of the value of the most frequent diameter (Dmax) is preferably 40% or more of the total volume of all pores, and more preferably 50% or more. In addition, the total volume of pores within ±20% of the value of the most frequent diameter (Dmax) is preferably 90% or less of the total pore volume. This means that the diameters of the pores in the platinum group element-supported silica gel of the present invention are uniform for pores near the most frequent diameter (Dmax).
　本実施形態に係るシリカゲルは、上記のＢＪＨ法により算出された最頻直径（Ｄｍａｘ）における微分細孔容積ΔＶ／Δ（ｌｏｇｄ）が、２～２０ｍＬ／ｇであることが好ましく、３～１２ｍＬ／ｇであることが特に好ましい（なお、上式において、ｄは細孔直径（ｎｍ）であり、Ｖは窒素ガス吸着容積である）。微分細孔容積ΔＶ／Δ（ｌｏｇｄ）が前記範囲に含まれるものは、最頻直径（Ｄｍａｘ）の付近に揃っている細孔の絶対量が極めて多いものと言える。 The silica gel according to this embodiment preferably has a differential pore volume ΔV/Δ(logd) at the most frequent diameter (Dmax) calculated by the BJH method described above of 2 to 20 mL/g, and particularly preferably 3 to 12 mL/g (in the above formula, d is the pore diameter (nm), and V is the nitrogen gas adsorption volume). Silica gels with differential pore volumes ΔV/Δ(logd) within the above range can be said to have an extremely large absolute amount of pores aligned near the most frequent diameter (Dmax).
　また、本実施形態に係るシリカゲルは、以上の細孔構造の特徴に加えて、その三次元構造が非結晶質であること、即ち、結晶性構造が認められないことが好ましい。このことは、本発明の異元素担持シリカゲルを粉末Ｘ線回折で分析した場合に、結晶性ピークが実質的に認められないことを意味する。なお、非結晶質のシリカゲルは、結晶性のシリカゲルに較べて、極めて生産性に優れている。 In addition to the above-mentioned pore structure characteristics, it is preferable that the silica gel according to this embodiment has a non-crystalline three-dimensional structure, i.e., no crystalline structure is observed. This means that when the foreign element-supported silica gel of the present invention is analyzed by powder X-ray diffraction, substantially no crystalline peaks are observed. Furthermore, non-crystalline silica gel is extremely superior in productivity compared to crystalline silica gel.
＜白金族元素担持シリカゲル＞
　白金族元素担持シリカゲルの平均粒子径は特段の制限はないが、粒子の凝集を抑制するために、１μｍ以上であることが好ましく、３μｍ以上であることがさらに好ましい。一方、粒子の表面積をある程度保つために１，０００μｍ以下であることが好ましく、８００μｍ以下であることがさらに好ましく、６００μｍ以下であることが特に好ましい。なお、白金族元素担持シリカゲルの平均粒子径は、ＪＩＳ　Ｋ　１１５０　（１９９４）　シリカゲル試験方法に記載の粒度分布測定方法に基づいて、レーザー回折式粒度分布測定装置により、体積平均粒子径として測定することができる。 <Platinum group element-supported silica gel>
The average particle size of the platinum group element-supported silica gel is not particularly limited, but is preferably 1 μm or more, more preferably 3 μm or more, in order to suppress particle aggregation. On the other hand, in order to maintain a certain degree of particle surface area, it is preferably 1,000 μm or less, more preferably 800 μm or less, and particularly preferably 600 μm or less. The average particle size of the platinum group element-supported silica gel can be measured as the volume average particle size by a laser diffraction particle size distribution measuring device based on the particle size distribution measuring method described in JIS K 1150 (1994) Silica Gel Test Method.
　白金族元素担持シリカゲルの全細孔容積は、エチレンとの接触効率向上の観点から、０．３ｍＬ／ｇ以上が好ましく、０．４ｍＬ／ｇ以上がより好ましく、０．５ｍＬ／ｇ以上がさらに好ましい。触媒担体として製造が実現可能な１．６ｍＬ／ｇ以下が好ましく、１．５ｍＬ／ｇ以下がより好ましく、１．３ｍＬ／ｇ以下がさらに好ましい。 The total pore volume of the platinum group element-supported silica gel is preferably 0.3 mL/g or more, more preferably 0.4 mL/g or more, and even more preferably 0.5 mL/g or more, from the viewpoint of improving the contact efficiency with ethylene. It is preferably 1.6 mL/g or less, which is feasible for production as a catalyst carrier, more preferably 1.5 mL/g or less, and even more preferably 1.3 mL/g or less.
　また、白金族元素担持シリカゲルの比表面積は、特段の制限はないが、８０～１２００ｍ２／ｇであることが好ましく、１００～１１００ｍ２／ｇであることがさらに好ましく、１２０～１０００ｍ２／ｇであることが特に好ましい。なお、これらの細孔容積及び比表面積の値は、ＪＩＳ　Ｋ　１１５０　（１９９４）　シリカゲル試験方法に記載の窒素吸着等温線によるＢ．Ｅ．Ｔ．式で求めることができる。 The specific surface area of the platinum group element-supported silica gel is not particularly limited, but is preferably 80 to 1200 m 2 /g, more preferably 100 to 1100 m 2 /g, and particularly preferably 120 to 1000 m 2 /g. The pore volume and specific surface area values can be determined by the B.E.T. equation using the nitrogen adsorption isotherm described in JIS K 1150 (1994) Silica Gel Test Method.
　本実施形態に係る白金族元素担持シリカゲルは、窒素ガス吸脱着法で測定した等温脱着曲線から、Ｅ．　Ｐ．　Ｂａｒｒｅｔｔ，　Ｌ．　Ｇ．　Ｊｏｙｎｅｒ，　Ｐ．　Ｈ．　Ｈａｋｌｅｎｄａ，　Ｊ．　Ａｍ．　Ｃｈｅｍ．　Ｓｏｃ．，　ｖｏｌ．　７３，　３７３　（１９５１）に記載のＢＪＨ法により算出される細孔分布曲線、即ち、細孔直径ｄ（ｎｍ）に対して微分窒素ガス吸着量（ΔＶ／Δ（ｌｏｇｄ）；Ｖは窒素ガス吸着容積）をプロットした図上での最頻直径（Ｄｍａｘ）が２０ｎｍ未満であることが好ましく、下限は特に制限はないが、好ましくは２ｎｍ以上である。 The platinum group element-supported silica gel according to this embodiment has a pore distribution curve calculated from an isothermal desorption curve measured by a nitrogen gas adsorption/desorption method using the BJH method described in E. P. Barrett, L. G. Joyner, P. H. Haklenda, J. Am. Chem. Soc., vol. 73, 373 (1951), that is, a graph plotting differential nitrogen gas adsorption amount (ΔV/Δ(logd); V is the nitrogen gas adsorption volume) against pore diameter d (nm) preferably having a modal diameter (Dmax) of less than 20 nm, with no particular lower limit, but preferably 2 nm or more.
　本実施形態に係る白金族元素担持シリカゲルは、上記の最頻直径（Ｄｍａｘ）の値の±２０％の範囲にある細孔の総容積が、全細孔の総容積の４０％以上であることが好ましく、５０％以上であることがさらに好ましい。また、上記の最頻直径（Ｄｍａｘ）の値を中心として±２０％の範囲にある細孔の総容積は、全細孔容積の９０％以下であることが好ましい。このことは、本発明の白金族元素担持シリカゲルが有する細孔の直径が、最頻直径（Ｄｍａｘ）付近の細孔で揃っていることを意味する。 In the platinum group element-supported silica gel of this embodiment, the total volume of pores within ±20% of the above-mentioned most frequent diameter (Dmax) is preferably 40% or more of the total volume of all pores, and more preferably 50% or more. In addition, the total volume of pores within ±20% of the above-mentioned most frequent diameter (Dmax) is preferably 90% or less of the total pore volume. This means that the pores in the platinum group element-supported silica gel of the present invention have a uniform diameter near the most frequent diameter (Dmax).
　また、本実施形態に係る白金族元素担持シリカゲルは、以上の細孔構造の特徴に加えて、その三次元構造が非結晶質であること、即ち、結晶性構造が認められないことが好ましい。このことは、本発明の異元素担持シリカゲルをＸ線回折で分析した場合に、結晶性ピークが実質的に認められないことを意味する。なお、本明細書において非結晶質のシリカゲルは、結晶性のシリカゲルに較べて、極めて生産性に優れている。 In addition to the above-mentioned pore structure characteristics, it is preferable that the platinum group element-supported silica gel according to this embodiment has a non-crystalline three-dimensional structure, i.e., no crystalline structure is observed. This means that when the foreign element-supported silica gel of the present invention is analyzed by X-ray diffraction, substantially no crystalline peaks are observed. In this specification, non-crystalline silica gel is extremely superior in productivity compared to crystalline silica gel.
　本実施形態に係る白金族元素担持シリカゲルは、エチレン分解処理に付される空間体積１００Ｌあたり、所期の効果を発揮させる観点から、０．５ｇ以上用いることが好ましい。１ｇ以上がより好ましく、２ｇ以上がさらに好ましく、１ｇ以上が最も好ましい。材料の価格の観点から、１０ｇ以下が好ましく、８ｇ以下がより好ましく、５ｇ以下がさらに好ましい。本発明のエチレン分解剤には白金族元素担持シリカゲルを、処理に付される空間体積に応じて、上記範囲より適宜選択される量を含めることができる。 From the viewpoint of exerting the intended effect, it is preferable to use 0.5 g or more of the platinum group element-supported silica gel according to this embodiment per 100 L of space volume subjected to ethylene decomposition treatment. 1 g or more is more preferable, 2 g or more is even more preferable, and 1 g or more is most preferable. From the viewpoint of the cost of the material, 10 g or less is preferable, 8 g or less is more preferable, and 5 g or less is even more preferable. The ethylene decomposition agent of the present invention can contain an amount of platinum group element-supported silica gel appropriately selected from the above range depending on the space volume subjected to treatment.
＜アルコール＞
　本実施形態のアルコールは、水酸基を有する有機化合物である。白金族元素担持シリカゲルとアルコールを共存させることで、水分が存在しても、白金族元素担持シリカゲルの触媒活性の低下を抑制することができる。その理由は、推定ではあるが、白金族元素担持シリカゲルの触媒活性点近傍に水が存在する場合に、水とアルコールが混和することで、触媒活性点近傍の疎水性が高まり、エチレンの到達が促進されるためであると考えている。 <Alcohol>
The alcohol in this embodiment is an organic compound having a hydroxyl group. By allowing the platinum group element-supported silica gel and the alcohol to coexist, it is possible to suppress the decrease in catalytic activity of the platinum group element-supported silica gel even in the presence of moisture. The reason for this is presumably that when water is present near the catalytic active sites of the platinum group element-supported silica gel, the miscibility of the water and the alcohol increases the hydrophobicity near the catalytic active sites, facilitating the arrival of ethylene.
　アルコールとしては、モノアルコールであっても、ジオールであっても、多価アルコールであってもよい。水溶性の観点から、炭素数が３以下のアルコールが好ましい。水溶性を有することで、高湿度下であっても、エチレン分解剤としての効果を発揮すると推定している。植物の近傍で利用する観点では、食品または食品添加物として使用されることが多いことから、エタノールが最も好ましい。 The alcohol may be a monoalcohol, a diol, or a polyhydric alcohol. From the viewpoint of water solubility, alcohols with three or less carbon atoms are preferred. It is presumed that the water solubility allows the alcohol to be effective as an ethylene decomposition agent even under high humidity conditions. From the viewpoint of use near plants, ethanol is most preferred since it is often used as a food or food additive.
　アルコールを共存させる方法としては、アルコールが白金族元素担持シリカゲルに到達する条件であればどのような方法であってもかまわない。アルコールそのものを共存させてもよく、化学反応によりアルコールを発生させて共存させてもよい。アルコールの共存は、白金族元素担持シリカゲルから３０ｃｍ以内の気体を採取し、ガスクロマトグラフィー法またはガスクロマトグラフィー質量分析法により分析することで、確認することができる。 Any method can be used to make the alcohol coexist as long as the conditions are such that the alcohol reaches the platinum group element-supported silica gel. The alcohol itself may be made to coexist, or it may be generated by a chemical reaction and made to coexist. The presence of alcohol can be confirmed by collecting gas within 30 cm of the platinum group element-supported silica gel and analyzing it by gas chromatography or gas chromatography mass spectrometry.
　アルコールの状態としては、気体であってもよく、液体であってもよく、固体であってもよい。固体である場合は、昇華するアルコールを用いることが好ましい。アルコールが液体の場合は、霧状であっても、液滴状であってもよく、何らかの媒体に含浸させた状態（本明細書中、「アルコール徐放剤」と記載する場合がある）であってもよい。噴霧器を用いることができる観点で、簡便に白金族元素担持シリカゲルとアルコールを共存させられるため、好ましい。媒体に含浸させる場合は、多孔質体に含浸させてもよい。徐放性を付与できる観点で、シリカゲルが好ましく、特にそのうちでも、十分な細孔容積を有する観点から、Ｂ型シリカが好ましい。 The state of the alcohol may be gas, liquid, or solid. If it is a solid, it is preferable to use an alcohol that sublimates. If the alcohol is a liquid, it may be in the form of a mist or droplets, or may be in a state in which it is impregnated into some medium (sometimes referred to as an "alcohol sustained-release agent" in this specification). From the viewpoint of being able to use a sprayer, it is preferable because it is easy to make the platinum group element-supported silica gel and the alcohol coexist. When impregnating a medium, it may be impregnated into a porous body. From the viewpoint of being able to impart sustained-release properties, silica gel is preferable, and among them, type B silica is particularly preferable from the viewpoint of having a sufficient pore volume.
　アルコールの共存条件としては、本実施形態のエチレン分解を開始させる時に共存を開始してもよく、開始させてから所期の時間が経過してから共存を開始させてもよい。アルコールは、エチレン分解の全期間に亘って共存させてもよく、エチレン分解を開始させる時に共存させ、その後新たに追加して共存させなくともよく、エチレン分解の全期間中に、間欠的に追加して共存させてもよい。
　エチレン分解の開始時のみに噴霧するのみの簡便な共存形態を取れることから、エチレン分解の開始時のみにアルコールを共存させてもよい。
　本実施形態において、アルコールの共存は、所期の効果を発揮させる観点から、白金族元素担持シリカゲルから３０ｃｍ以内の気体におけるアルコール量が、白金族元素担持シリカゲル１ｇあたり、２５０ｐｐｍ以上となることが好ましく、３００ｐｐｍ以上がより好ましく、５００ｐｐｍ以上がさらに好ましく、８００ｐｐｍ以上が特に好ましく、１０００ｐｐｍ以上が最も好ましい。上限は特段に制限がないが、経済性の観点から、２０００００ｐｐｍ以下が好ましく、１５００００ｐｐｍ以下がより好ましく、１０００００ｐｐｍ以下がさらに好ましく、８０００ｐｐｍ以下が殊更に好ましく、７０００ｐｐｍ以下が特に好ましく、６０００ｐｐｍ以下が最も好ましい。
　本発明のエチレン分解剤が、アルコールと白金族元素担持シリカゲルの両者を含む場合、白金族元素担持シリカゲルとアルコールの両者は同一のパッケージに含めてもよいし、あるいは別個のパッケージにそれぞれ含めても良く、好ましくはそれぞれ別個に分包される。例えば、白金族元素担持シリカゲルは、粉末状、ペレット状、またはタブレット状のものをエチレン及びアルコール透過性のある包材に入れてもよく、ペレット状、タブレット状のものをそのまま用いてもよく、籠状のものに保持してもよい。アルコールについては、取り扱い性の観点から、何らかの媒体に含浸させた状態のもの（アルコール徐放剤）をアルコール透過性のある包材に入れてもよい。
　本発明のエチレン分解剤に含まれるアルコールと白金族元素担持シリカゲルの各量は、エチレン分解処理に付される空間において所期の効果を発揮することが可能な任意の量とすることができ、白金族元素担持シリカゲルは処理に付される空間体積に応じて、上記範囲より適宜選択される量を含めることができる。アルコールは所期の効果を発揮させる観点から、白金族元素担持シリカゲル１ｇあたりの量として、白金族元素担持シリカゲルから３０ｃｍ以内の気体におけるアルコール量が上記範囲を達成することが可能な任意の量にて適宜含めることができる。 Regarding the conditions for the coexistence of the alcohol, the coexistence may be started at the start of the ethylene decomposition of the present embodiment, or may be started after a predetermined time has elapsed since the start of the decomposition. The alcohol may be made to coexist throughout the entire period of ethylene decomposition, may be made to coexist at the start of ethylene decomposition and then not newly added to be made to coexist therewith, or may be made to coexist by intermittently adding the alcohol during the entire period of ethylene decomposition.
Since a simple coexistence form of spraying only at the start of ethylene decomposition can be adopted, the alcohol may be made to coexist only at the start of ethylene decomposition.
In this embodiment, the coexistence of alcohol is such that, from the viewpoint of exerting the desired effect, the amount of alcohol in the gas within 30 cm from the platinum group element-supported silica gel is preferably 250 ppm or more per 1 g of the platinum group element-supported silica gel, more preferably 300 ppm or more, even more preferably 500 ppm or more, particularly preferably 800 ppm or more, and most preferably 1000 ppm or more. There is no particular upper limit, but from the viewpoint of economic efficiency, it is preferably 200000 ppm or less, more preferably 150000 ppm or less, even more preferably 100000 ppm or less, particularly preferably 8000 ppm or less, particularly preferably 7000 ppm or less, and most preferably 6000 ppm or less.
When the ethylene decomposition agent of the present invention contains both an alcohol and a platinum group element-supported silica gel, the platinum group element-supported silica gel and the alcohol may be contained in the same package or in separate packages, and preferably each is separately packaged. For example, the platinum group element-supported silica gel may be in the form of a powder, pellet, or tablet and placed in an ethylene and alcohol-permeable packaging material, and the pellet or tablet form may be used as is, or may be held in a cage. From the viewpoint of handling, the alcohol may be impregnated in some medium (alcohol sustained release agent) and placed in an alcohol-permeable packaging material.
The amount of each of the alcohol and the platinum group element-supported silica gel contained in the ethylene decomposition agent of the present invention may be any amount capable of exerting the desired effect in the space subjected to the ethylene decomposition treatment, and the platinum group element-supported silica gel may be contained in an amount appropriately selected from the above range depending on the volume of the space subjected to the treatment. From the viewpoint of exerting the desired effect, the alcohol may be contained in any amount per gram of the platinum group element-supported silica gel capable of achieving the above-mentioned range of the amount of alcohol in the gas within 30 cm from the platinum group element-supported silica gel.
＜その他の成分＞
　本発明のエチレン分解剤は、アルコール共存下で用いる白金族元素担持シリカゲル以外に、所期のエチレン分解能を発揮する範囲において、その他の成分を含んでいても良い。
　具体的には、白金族元素担持シリカゲルの成形に用いる結着剤などを含んでいてもよい。 <Other ingredients>
The ethylene decomposition agent of the present invention may contain other components in addition to the platinum group element-supported silica gel used in the presence of alcohol, as long as the desired ethylene decomposition ability is exhibited.
Specifically, it may contain a binder used in forming the platinum group element-supported silica gel.
＜植物＞
　本発明の鮮度保持対象の植物としては、エチレンによって劣化が進む植物が挙げられる。植物としては、例えば、リンゴ、サクランボ、モモ、アオウメなどの果実、オレンジ、グレープフルーツ、ミカン、スダチなどの柑橘類果実、カキ、イチジク、イチゴ、キウイフルーツ、ブドウ、ブルーベリー、バナナ、マンゴー、メロン、パパイヤ、レイシ（ライチ）、アンズ、アボカド、カンタループ、グアバ、ネクタリン、ナシ（ニホンナシ、セイヨウナシなど）、プラム等の果物；ダイコン、ニンジン、ゴボウなどの根菜類、サツマイモ、タマネギ、ショウガ、サトイモ、ナガイモ等の土物類；アスパラガス、キャベツ、レタス、ホウレンソウ、ハクサイ、カリフラワー、ブロッコリー、タケノコ等の葉茎菜類；トマト、ナス、カボチャ、ピーマン、キュウリ等の果菜類；ワラビ、ゼンマイ等の山菜；シイタケ、エリンギ、ブナシメジ、ホンシメジ、エノキダケ、マイタケ等の菌茸類；キク、バラ、ユリ、ラン等の花卉類が挙げられる。花卉類は切り花の形態でもよく、鉢植えの形態でもよく、花弁の形態でもよい。
　この中でも、エチレンによる劣化の影響が大きい観点で、果物類、葉茎菜類が好ましい。 <Plants>
Plants that are the subject of freshness preservation in the present invention include plants that deteriorate due to ethylene. Examples of plants include fruits such as apples, cherries, peaches, and blue plums, citrus fruits such as oranges, grapefruits, mandarins, and sudachi, persimmons, figs, strawberries, kiwi fruits, grapes, blueberries, bananas, mangoes, melons, papayas, lychees, apricots, avocados, cantaloupes, guavas, nectarines, pears (Japanese pears, European pears, etc.), and plums; radishes, carrots, burdock, etc. Examples of suitable vegetables include root vegetables, sweet potatoes, onions, ginger, taro, Chinese yam, and other earthen vegetables; leafy vegetables such as asparagus, cabbage, lettuce, spinach, Chinese cabbage, cauliflower, broccoli, and bamboo shoots; fruit vegetables such as tomatoes, eggplants, pumpkins, bell peppers, and cucumbers; wild plants such as bracken and fern; fungi such as shiitake mushrooms, king oyster mushrooms, buna-shimeji mushrooms, hon-shimeji mushrooms, enoki mushrooms, and maitake mushrooms; and flowers such as chrysanthemums, roses, lilies, and orchids. Flowers may be in the form of cut flowers, potted plants, or petals.
Among these, fruits and leafy vegetables are preferred because they are more susceptible to deterioration by ethylene.
＜エチレン分解剤を備えた物品＞
　本発明のエチレン分解剤は、エチレンの分解が要求される用途であれば、制限なく用いることができる。特に、植物の鮮度保持剤特は、植物の鮮度保持が要求される様々な物品に備えることができる。
　本発明のエチレン分解剤及び植物の鮮度保持剤を備えた物品の具体例としては、植物の保管又は輸送に用いられる物品、例えば、袋、容器、フィルター、冷蔵庫、冷凍庫、コンテナ、空調機、車両、船舶、航空機等のものが挙げられる。
　エチレンを発生する化学反応において、例えば、平衡状態を制御したいときに、反応器に本発明のエチレン分解剤を備えた物品としてもよい。 <Article with ethylene decomposition agent>
The ethylene decomposition agent of the present invention can be used without limitation in any application requiring the decomposition of ethylene. In particular, the plant freshness preservation agent can be provided in various articles requiring the preservation of the freshness of plants.
Specific examples of articles comprising the ethylene decomposer and plant freshness-preserving agent of the present invention include articles used for storing or transporting plants, such as bags, containers, filters, refrigerators, freezers, containers, air conditioners, vehicles, ships, and aircraft.
In a chemical reaction that generates ethylene, for example, when it is desired to control the equilibrium state, the ethylene decomposition agent of the present invention may be provided in a reactor as an article.
　物品の具体的な内容としては、白金族元素担持シリカゲルとアルコールをパッケージにしたものを用いてもよく、白金族元素担持シリカゲルとアルコール発生源を備えたデバイスとしてもよい。 Specific examples of the product include a package of platinum group element-supported silica gel and alcohol, or a device equipped with platinum group element-supported silica gel and an alcohol generating source.
　白金族元素担持シリカゲルとアルコールを含むパッケージは、白金族元素担持シリカゲルとアルコールをそれぞれ別個に分包したものを用いてもよい。白金族元素担持シリカゲルは、粉末状、ペレット状、またはタブレット状のものをエチレン及びアルコール透過性のある包材に入れてもよく、ペレット状、タブレット状のものをそのまま用いてもよく、籠状のものに保持してもよい。
　アルコールについては、取り扱い性の観点から、担体に含浸させて用いてもよい。 The package containing the platinum group element-supported silica gel and the alcohol may be one in which the platinum group element-supported silica gel and the alcohol are separately packaged. The platinum group element-supported silica gel may be in the form of a powder, pellet, or tablet and placed in a packaging material that is permeable to ethylene and alcohol, or the pellet or tablet form may be used as is, or may be held in a cage.
From the viewpoint of ease of handling, the alcohol may be used by impregnating a carrier.
　白金族元素担持シリカゲルとアルコール発生源を備えたデバイスは、一体となっていてもよく、別体になっていてもよい。別体になっている場合は、白金族元素担持シリカゲルにアルコールが到達すれば、構造や設置距離に制限はない。
　アルコール発生源としては、アルコールを揮発、蒸発、または噴霧させる機構を備えていれば、構造上の制限はない。アルコールを揮発させる機構としては、アルコールを含浸した担体を保持する機構が挙げられる。アルコールを蒸発させる機構としては、加熱機構、超音波機構が挙げられる。アルコールを噴霧させる機構としては、霧吹きを含む噴霧機が挙げられる。本発明の鮮度保持デバイスとして用いる場合は、加温による劣化を防ぐため、揮発または噴霧が好ましい。 The device including the platinum group element-supported silica gel and the alcohol generating source may be integrated or separate. If they are separate, there are no limitations on the structure or installation distance as long as the alcohol reaches the platinum group element-supported silica gel.
The alcohol source is not structurally limited as long as it has a mechanism for volatilizing, vaporizing, or spraying alcohol. The mechanism for volatilizing alcohol includes a mechanism for holding a carrier impregnated with alcohol. The mechanism for evaporating alcohol includes a heating mechanism and an ultrasonic mechanism. The mechanism for spraying alcohol includes a sprayer including a sprayer. When used as the freshness-preserving device of the present invention, evaporation or spraying is preferred to prevent deterioration due to heating.
＜エチレン分解剤の製造方法＞
　本発明のエチレン分解剤は、白金族元素担持シリカゲルを製造することによって、ならびに白金族元素担持シリカゲルにアルコールを共存させることで製造できる。
　共存の方法は、前述のとおりである。 <Production method of ethylene decomposition agent>
The ethylene decomposition agent of the present invention can be produced by producing a platinum group element-supported silica gel, and by making an alcohol coexist with the platinum group element-supported silica gel.
The method of coexistence is as described above.
＜白金族元素担持シリカゲルの製造方法＞
　白金族元素担持シリカゲルの製造方法は特段の制限はないが、好ましくは、白金元素含有化合物や白金族元素を含む有機錯体等の白金族元素の原料とシリカゲルとの混合物を還元することにより得ることができる。例えば、白金族元素の原料を含む水溶液を調製し、シリカゲルを含浸させ、乾燥後、還元処理を行うことにより白金族元素担持シリカゲルを得ることができる。 <Method of producing platinum group element-supported silica gel>
Although there is no particular limitation on the method for producing the platinum group element-supported silica gel, it can be preferably obtained by reducing a mixture of a platinum group element raw material, such as a platinum-containing compound or an organic complex containing a platinum group element, and silica gel. For example, the platinum group element-supported silica gel can be obtained by preparing an aqueous solution containing the platinum group element raw material, impregnating silica gel with the solution, drying the solution, and then carrying out a reduction treatment.
　白金族元素含有化合物としては、例えば、白金族元素の塩酸塩、硝酸塩、硫酸塩等が挙げられる。 Examples of compounds containing platinum group elements include hydrochlorides, nitrates, sulfates, etc. of platinum group elements.
　白金族元素を担持させる前のシリカゲルのＢＥＴ比表面積、細孔容積、及び粒子径は特段の制限はなく、所望の白金族元素担持シリカゲルが得られるように、適宜選択すればよい。従って、これらの好ましい範囲は上述の白金族元素担持シリカゲルで挙げた範囲と同じである。 There are no particular limitations on the BET specific surface area, pore volume, and particle size of the silica gel before the platinum group element is loaded, and these may be appropriately selected so as to obtain the desired platinum group element-loaded silica gel. Therefore, the preferred ranges for these are the same as those given above for the platinum group element-loaded silica gel.
＜シリカゲルの製造方法＞
　シリカゲルの製造方法は特段の制限はなく、例えば、ケイ酸アルカリ塩を加水分解して得られるシリカヒドロゲルを洗浄、乾燥して製造する方法を用いることができる。代表的な方法としては、ケイ酸アルカリ塩と硫酸を混合してケイ酸を得たあと熟成し、得られたケイ酸ゲルをから不純物であるナトリウム等を水洗して除去した後、シリカヒドロゲルをさらに熟成することにより、比表面積、細孔容積、細孔径などを調整してから、シリカヒドロゲル中の水分を除去してシリカゲルを得る方法が挙げられる。
　または、シリコンアルコキシドを加水分解して得られるシリカヒドロゲルを、熟成すること無しに水熱処理する方法を応用してシリカゲルを製造する方法も挙げられる。
　その他には、無機原料と有機鋳型剤を混合し、反応させることにより、有機鋳型剤のまわりに無機物の骨格が形成された有機物と無機物の複合体を形成させ、次いで、得られた複合体から有機物を除去することにより、シリカゲルを製造する方法が挙げられる。
　この中でも、製造したシリカゲルが含むアルカリ金属などの不純物が少ない観点で、好ましくは、シリコンアルコキシドを加水分解する方法が挙げられる。 <Method of producing silica gel>
The method for producing silica gel is not particularly limited, and for example, a method of producing silica gel by washing and drying the silica hydrogel obtained by hydrolyzing an alkali silicate can be used. A representative method includes a method of mixing an alkali silicate with sulfuric acid to obtain silicic acid, maturing the mixture, washing the obtained silicic acid gel to remove impurities such as sodium, and then maturing the silica hydrogel to adjust the specific surface area, pore volume, pore diameter, etc., and then removing the water in the silica hydrogel to obtain silica gel.
Alternatively, silica gel can be produced by applying a method in which silica hydrogel obtained by hydrolyzing silicon alkoxide is subjected to hydrothermal treatment without aging.
Another method for producing silica gel is to mix and react an inorganic raw material with an organic templating agent to form an organic-inorganic composite in which an inorganic skeleton is formed around the organic templating agent, and then remove the organic material from the composite.
Among these, the method of hydrolyzing silicon alkoxide is preferable from the viewpoint of producing silica gel containing less impurities such as alkali metals.
　ケイ酸アルカリ塩を加水分解して得られるシリカヒドロゲルを洗浄、乾燥して製造する場合、シリコンアルコキシドとして、ケイ酸のアルカリ金属塩を用いる。アルカリ金属としては、ナトリウム、カリウムを用いることが好ましい。 When producing silica hydrogel by washing and drying the silica hydrogel obtained by hydrolysis of an alkali silicate, an alkali metal salt of silicate is used as the silicon alkoxide. As the alkali metal, sodium or potassium is preferably used.
　シリコンアルコキシドを加水分解して得られるシリカヒドロゲルを、熟成すること無しに水熱処理する方法を応用する場合、シリコンアルコキシドとしては、トリメトキシシラン、テトラメトキシシラン、トリエトキシシラン、テトラエトキシシラン、テトラプロポキシシラン、テトラブトキシシラン等の炭素数１～４の低級アルキル基を有するトリまたはテトラアルコキシシラン或いはそれらのオリゴマーが挙げられるが、好ましくはテトラメトキシシラン、テトラエトキシシラン及びそれらのオリゴマーである。以上のシリコンアルコキシドは蒸留により容易に精製し得るので、高純度のシリカゲルの原料として好適である。シリコンアルコキシド中の金属不純物の総含有量は、通常好ましくは１００ｐｐｍ以下、更に好ましくは１０ｐｐｍ以下である。金属不純物の含有量は、シリカゲル中の不純物の測定法と同じ方法で測定できる。 When applying the method of hydrothermally treating silica hydrogel obtained by hydrolysis of silicon alkoxide without aging, examples of silicon alkoxide include tri- or tetraalkoxysilanes having a lower alkyl group with 1 to 4 carbon atoms, such as trimethoxysilane, tetramethoxysilane, triethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane, or oligomers thereof, with tetramethoxysilane, tetraethoxysilane, and tetrapropoxysilane being preferred. The above silicon alkoxides can be easily purified by distillation, and are therefore suitable as raw materials for high-purity silica gel. The total content of metal impurities in silicon alkoxides is usually preferably 100 ppm or less, and more preferably 10 ppm or less. The content of metal impurities can be measured by the same method as that for measuring impurities in silica gel.
　シリコンアルコキシドの加水分解は、シリコンアルコキシド１モルに対して、通常２～２０モル、好ましくは３～１０モル、特に好ましくは４～８モルの水を用いて行う。シリコンアルコキシドの加水分解により、シリカのヒドロゲルとアルコールが生成する。この加水分解反応は、通常、室温から１００℃程度であるが、加圧下で液相を維持することでより高い温度で行うことも可能である。反応時間は反応液組成（シリコンアルコキシドの種類や、水とのモル比）並びに反応温度に依存し、ゲル化するまでの時間が異なるので、一概には規定されない。反応時間はヒドロゲルの破壊応力が６ＭＰａを越えない時間である。なお、反応系に、触媒として、酸、アルカリ、塩類などを添加することで加水分解を促進させることができる。しかしながら、かかる添加物の使用は、後述のように、生成したヒドロゲルの熟成を引き起こすことになるので、シリカゲルの製造においては使用しないことが好ましい。 The hydrolysis of silicon alkoxide is usually carried out using 2 to 20 moles, preferably 3 to 10 moles, and particularly preferably 4 to 8 moles of water per mole of silicon alkoxide. Hydrolysis of silicon alkoxide produces silica hydrogel and alcohol. This hydrolysis reaction is usually carried out at room temperature to about 100°C, but it can also be carried out at higher temperatures by maintaining the liquid phase under pressure. The reaction time depends on the composition of the reaction liquid (type of silicon alkoxide and molar ratio with water) and the reaction temperature, and the time until gelation varies, so it is not generally specified. The reaction time is the time during which the breaking stress of the hydrogel does not exceed 6 MPa. Note that hydrolysis can be promoted by adding acids, alkalis, salts, etc. as catalysts to the reaction system. However, the use of such additives causes the generated hydrogel to mature, as described below, so it is preferable not to use them in the production of silica gel.
　上記のシリコンアルコキシドの加水分解反応では、シリコンアルコキシドが加水分解してシリケートが生成するが、引き続いて該シリケートの縮合反応が起こり、反応液の粘度が上昇し、最終的にゲル化してシリカヒドロゲルとなる。シリカゲルを製造するためには、上記の加水分解により生成したシリカのヒドロゲルの硬さが上昇しないように、実質的に熟成することなく、直ちに水熱処理を行うことが好ましい。 In the hydrolysis reaction of silicon alkoxide, silicon alkoxide is hydrolyzed to produce silicate, which is then condensed, causing the viscosity of the reaction solution to increase, and finally gelling to form silica hydrogel. In order to produce silica gel, it is preferable to immediately carry out hydrothermal treatment without substantial aging, so that the hardness of the silica hydrogel produced by the hydrolysis does not increase.
　上記にある、加水分解により生成したシリカのヒドロゲルを、実質的に熟成することなく、直ちに水熱処理を行うということは、シリカのヒドロゲルが生成した直後の軟弱な状態が維持されたままで、次の、水熱処理に供するようにするということを意味する。シリコンアルコキシドの加水分解反応系に酸、アルカリ、塩類等を添加すること、または該加水分解反応の温度を厳しくし過ぎることなどは、ヒドロゲルの熟成を進行させるため好ましくない。また、加水分解後の後処理における水洗、乾燥、放置などにおいて、必要以上に温度や時間をかけない方が好ましい。 The above-mentioned hydrothermal treatment of the silica hydrogel produced by hydrolysis immediately without substantial maturation means that the silica hydrogel is subjected to the next hydrothermal treatment while maintaining the soft state it has immediately after production. It is not preferable to add acids, alkalis, salts, etc. to the hydrolysis reaction system of silicon alkoxide, or to make the temperature of the hydrolysis reaction too strict, as these will accelerate the maturation of the hydrogel. In addition, it is preferable not to use more heat or time than necessary in the post-treatments following hydrolysis, such as washing with water, drying, and leaving.
　水熱処理の条件としては、水の状態が液体、気体のいずれでもよく、溶媒や他の気体によって希釈されていてもよいが、好ましくは液体の水が使われる。シリカのヒドロゲルに対して、通常０．１～１０質量倍、好ましくは０．５～５質量倍、特に好ましくは１～３質量倍の水を加えてスラリー状とし、通常４０～２５０℃、好ましくは５０～２００℃の温度で、通常０．１～１００時間、好ましくは１～１０時間実施される。水熱処理に使用される水には低級アルコール類、メタノール、エタノール、プロパノールなどが含まれてもよい。また、メンブランリアクターなどを作る目的で、シリカゲルを膜状あるいは層状に粒子、基板、あるいは管などの基体上に形成させた材料の場合にも、この水熱処理方法は適用される。 　The conditions for hydrothermal treatment may be that the water is either liquid or gaseous, and may be diluted with a solvent or other gas, but liquid water is preferably used. To the silica hydrogel, usually 0.1 to 10 times by mass, preferably 0.5 to 5 times by mass, and particularly preferably 1 to 3 times by mass, of water is added to form a slurry, and the treatment is usually carried out at a temperature of 40 to 250°C, preferably 50 to 200°C, for usually 0.1 to 100 hours, preferably 1 to 10 hours. The water used for hydrothermal treatment may contain lower alcohols, methanol, ethanol, propanol, etc. This hydrothermal treatment method is also applicable to materials in which silica gel is formed in the form of a film or layer on a substrate such as particles, substrate, or tube for the purpose of making a membrane reactor, etc.
　以上の水熱処理条件において、温度を高くすると得られるシリカゲルの細孔径、細孔容積が大きくなる傾向がある。また、処理時間とともに、得られるシリカゲルの比表面積は、一度極大に達した後、緩やかに減少する傾向がある。以上の傾向を踏まえて、所望の物性値に応じて条件を適宜選択する必要があるが、水熱処理は、シリカゲルの物性を変化させる目的なので、通常、前記の加水分解の反応条件より高温条件とすることが好ましい。 In the above hydrothermal treatment conditions, the pore diameter and pore volume of the resulting silica gel tend to increase as the temperature increases. In addition, the specific surface area of the resulting silica gel tends to reach a maximum once and then gradually decrease with the treatment time. In light of the above trends, it is necessary to select appropriate conditions according to the desired physical property values, but since the purpose of the hydrothermal treatment is to change the physical properties of the silica gel, it is usually preferable to use higher temperature conditions than the above hydrolysis reaction conditions.
　水熱処理の温度、時間を上記範囲外に設定すると本発明のシリカゲルを得ることが困難となる。例えば、水熱処理の温度が高すぎると、シリカゲルの細孔径、細孔容積が大きくなりすぎ、また、細孔分布も広がる。逆に、水熱処理の温度が低過ぎると、生成するシリカゲルは、架橋度が低く、熱安定性に乏しくなる傾向がある。 If the temperature and time of the hydrothermal treatment are set outside the above ranges, it becomes difficult to obtain the silica gel of the present invention. For example, if the temperature of the hydrothermal treatment is too high, the pore diameter and pore volume of the silica gel will become too large, and the pore distribution will also become broader. Conversely, if the temperature of the hydrothermal treatment is too low, the silica gel produced will tend to have a low degree of cross-linking and poor thermal stability.
　なお、水熱処理をアンモニア水中で行うと、純水中で行う場合よりも低温で同様の効果が得られる。また、アンモニア水中で水熱処理すると、純水中で処理する場合と比較して、最終的に得られるシリカゲルは一般に疎水性となるが、通常３０～２５０℃、好ましくは４０～２００℃という比較的高温で水熱処理すると、特に疎水性が高くなる。ここでのアンモニア水のアンモニア濃度としては、好ましくは０．００１～１０％、特に好ましくは０．００５～５％である。 When hydrothermal treatment is performed in ammonia water, the same effect can be obtained at a lower temperature than when it is performed in pure water. Furthermore, when hydrothermal treatment is performed in ammonia water, the final silica gel generally becomes more hydrophobic than when it is treated in pure water, but when hydrothermal treatment is performed at a relatively high temperature, usually 30 to 250°C, preferably 40 to 200°C, the hydrophobicity becomes particularly high. The ammonia concentration of the ammonia water here is preferably 0.001 to 10%, and particularly preferably 0.005 to 5%.
　水熱処理されたシリカヒドロゲルは、通常４０～２００℃、好ましくは６０～１２０℃で乾燥する。乾燥方法は特に限定されるものではなく、バッチ式でも連続式でもよく、且つ、常圧でも減圧下でも乾燥することができる。必要に応じ、原料のシリコンアルコキシドに由来する炭素分が含まれている場合には、通常４００～６００℃で焼成除去することができる。また、表面状態をコントロールするため、最高９００℃の温度で焼成することもある。更に、必要に応じて粉砕、分級してもよい。 The hydrothermally treated silica hydrogel is usually dried at 40 to 200°C, preferably 60 to 120°C. There are no particular limitations on the drying method, and it can be either batch or continuous, and can be dried at normal pressure or reduced pressure. If carbon derived from the silicon alkoxide raw material is present as needed, it can be removed by baking, usually at 400 to 600°C. To control the surface condition, it may also be baked at a maximum temperature of 900°C. Furthermore, it may be crushed and classified as needed.
　有機鋳型剤を用いてシリカゲルを製造する場合、無機原料としては、テトラメトキシシラン、テトラエトキシシラン、テトラプロポキシシラン等のアルコキシシラン、ケイ酸ソーダ、カネマイト（ｋａｎｅｍｉｔｅ、ＮａＨＳｉ２Ｏ５・３Ｈ２Ｏ）、シリカ、シリカ－金属複合酸化物等を用いることができる。これらは、単独で用いてもよく、２種以上を併用してもよい。 When producing silica gel using an organic templating agent, the inorganic raw material may be an alkoxysilane such as tetramethoxysilane, tetraethoxysilane, or tetrapropoxysilane, sodium silicate, kanemite (NaHSi 2 O 5.3H 2 O), silica, or a silica-metal composite oxide, etc. These may be used alone or in combination of two or more kinds.
　有機鋳型剤として使用される有機化合物には、特段の制限はないが、例えば、界面活性剤等が挙げられる。界面活性剤は陽イオン性、陰イオン性、非イオン性のうちのいずれでもよい。具体的には、アルキルトリメチルアンモニウム（好ましくはアルキル基の炭素数が８～１８のアルキルトリメチルアンモニウム）、アルキルアンモニウム、ジアルキルジメチルアンモニウム、ベンジルアンモニウムの塩化物、臭化物、ヨウ化物又は水酸化物の他、脂肪酸塩、アルキルスルホン酸塩、アルキルリン酸塩、ポリエチレンオキサイド系非イオン性界面活性剤、一級アルキルアミン、トリブロックコポリマー型のポリアルキレンオキサイド、グリセリン脂肪酸エステル、ポリグリセリン脂肪酸エステル等が挙げられる。これらは、単独で用いてもよく、２種以上を併用して用いてもよい。 The organic compound used as the organic template agent is not particularly limited, but examples thereof include surfactants. The surfactant may be cationic, anionic, or nonionic. Specific examples include chlorides, bromides, iodides, or hydroxides of alkyltrimethylammonium (preferably alkyltrimethylammonium with an alkyl group having 8 to 18 carbon atoms), alkylammonium, dialkyldimethylammonium, and benzylammonium, as well as fatty acid salts, alkylsulfonates, alkylphosphates, polyethylene oxide-based nonionic surfactants, primary alkylamines, triblock copolymer-type polyalkylene oxides, glycerin fatty acid esters, and polyglycerin fatty acid esters. These may be used alone or in combination of two or more.
　無機原料と有機鋳型剤を混合する場合、適当な溶媒を用いることができる。溶媒としては、特段の制限はないが、例えば水、有機溶媒、水と有機溶媒との混合物等が挙げられる。 When mixing the inorganic raw material and the organic templating agent, a suitable solvent can be used. There are no particular limitations on the solvent, but examples include water, an organic solvent, and a mixture of water and an organic solvent.
　無機物と有機物の複合体の形成方法は、特に限定されるものではないが、例えば、有機鋳型剤を溶媒に溶解後、無機原料を添加し、所定のｐＨに調製した後に、反応混合物を所定の温度に保持して縮重合反応を行う方法が挙げられる。縮重合反応の反応温度は使用する有機鋳型剤や無機原料の種類や濃度によって異なるが、通常０～１００℃程度が好ましく、より好ましくは３５～８０℃である。 The method for forming a composite of inorganic and organic substances is not particularly limited, but an example is a method in which an organic templating agent is dissolved in a solvent, inorganic raw materials are added, the pH is adjusted to a specified value, and the reaction mixture is then maintained at a specified temperature to carry out a condensation polymerization reaction. The reaction temperature for the condensation polymerization reaction varies depending on the type and concentration of the organic templating agent and inorganic raw materials used, but is usually preferably around 0 to 100°C, and more preferably 35 to 80°C.
　縮重合反応の反応時間は、通常１～２４時間程度が好ましい。また、上記の縮重合反応は、静置状態、撹拌状態のいずれで行ってもよく、またそれらを組み合わせて行ってもよい。 The reaction time for the condensation polymerization reaction is usually preferably about 1 to 24 hours. The condensation polymerization reaction may be carried out either in a stationary state or in a stirred state, or in a combination of these.
　縮重合反応後に得られる複合体から有機物を除去することによって、シリカゲルが得られる。有機物と無機物の複合体からの有機物の除去は、４００～８００℃で焼成する方法、水やアルコール等の溶媒で処理する方法等の方法により行うことができる。 Silica gel is obtained by removing the organic matter from the complex obtained after the condensation polymerization reaction. The organic matter can be removed from the complex of organic and inorganic matter by baking at 400 to 800°C or by treating with a solvent such as water or alcohol.
　結晶構造を有しないシリカゲルは、水中熱安定性が高くなる傾向にある。界面活性剤等の有機鋳型剤が、有機鋳型剤としての機能を発揮するほどの量は存在しない条件下で加水分解すると、結晶構造を含みにくい。さらに、有機鋳型剤を用いない場合、有機鋳型剤を除去するための高温での焼成が不要になるため、内部のシラノール基量を多くすることができることから、有機鋳型剤を用いない条件下で加水分解することが好ましい。 Silica gel that does not have a crystalline structure tends to have high thermal stability in water. If hydrolysis is performed under conditions in which an organic templating agent such as a surfactant is not present in an amount sufficient to function as an organic templating agent, it is unlikely to have a crystalline structure. Furthermore, if an organic templating agent is not used, high-temperature baking to remove the organic templating agent is not required, and the amount of internal silanol groups can be increased, so it is preferable to perform hydrolysis under conditions in which no organic templating agent is used.
＜エチレン分解方法＞
　本発明のエチレン分解方法は、白金族元素担持シリカゲルとアルコールを共存させて行う。アルコールの共存の方法は、前述のとおりである。
　本発明のエチレン分解方法は、エチレンと植物が存在する場合に、植物の鮮度保持方法として用いることができる。すなわち、本発明のエチレン分解方法において、白金族元素担持シリカゲルとアルコールの共存条件下に、植物を保存することによって、エチレンを分解して植物の劣化を防ぎ、植物の鮮度を保持することができる。
　本発明のエチレン分解方法または植物の鮮度保持方法は、例えば、本発明のエチレン分解剤、または鮮度保持剤を備えた物品を用いることで実施できる。
　本発明のエチレン分解方法では、酸素存在下、エチレンを二酸化炭素と水まで分解することができる。 <Method for Decomposing Ethylene>
The ethylene decomposition method of the present invention is carried out in the coexistence of a platinum group element-supported silica gel and an alcohol, as described above.
The ethylene decomposition method of the present invention can be used as a method for preserving the freshness of a plant when ethylene and the plant are present. That is, in the ethylene decomposition method of the present invention, by preserving the plant in the coexistence of platinum group element-supported silica gel and alcohol, ethylene is decomposed to prevent deterioration of the plant and preserve the freshness of the plant.
The method for decomposing ethylene or the method for preserving the freshness of a plant of the present invention can be carried out, for example, by using an article provided with the ethylene decomposing agent or the freshness preserving agent of the present invention.
In the method for decomposing ethylene of the present invention, ethylene can be decomposed into carbon dioxide and water in the presence of oxygen.
　本発明のエチレン分解方法は、―４０℃以上で実施することができる。植物が凍結しない観点から、―４℃以上がより好ましく、０℃以上がさらに好ましい。植物の保管の観点から、４０℃以下が好ましく、３０℃以下がより好ましく、２０℃以下がさらに好ましく、１５℃以下が特に好ましい。 The ethylene decomposition method of the present invention can be carried out at -40°C or higher. From the viewpoint of preventing the plant from freezing, -4°C or higher is more preferable, and 0°C or higher is even more preferable. From the viewpoint of storing the plant, 40°C or lower is preferable, 30°C or lower is more preferable, 20°C or lower is even more preferable, and 15°C or lower is particularly preferable.
　本発明のエチレン分解方法は、白金族元素担持シリカゲルとアルコールを共存させることにより、従来適用が難しかった、水分が６０ｍｇ／Ｌ（ｐｐｍ）以上の条件下で実施することができる。水分量としては、７０ｐｐｍ以上であってもよく、８０ｐｐｍ以上であってもよい。植物の一般的な保存条件である観点で、１０００００ｐｐｍ以下が好ましく、８００００ｐｐｍ以下がより好ましく、７５０００ｐｐｍ以下が好ましい。 The ethylene decomposition method of the present invention can be carried out under conditions of moisture of 60 mg/L (ppm) or more, which was previously difficult to apply, by allowing platinum group element-supported silica gel and alcohol to coexist. The moisture content may be 70 ppm or more, or 80 ppm or more. From the perspective of typical storage conditions for plants, 100,000 ppm or less is preferable, 80,000 ppm or less is more preferable, and 75,000 ppm or less is preferable.
　飽和水蒸気量は、温度によって異なるため、―４０℃の場合、水分が８０ｐｐｍ以上であってもよく、８５ｐｐｍ以上であってもよい。上限は特に制限がないが、１８８ｐｐｍ以下であってよく、１８５ｐｐｍ以下であってよい。
　温度が―４℃の場合、水分が１０００ｐｐｍ以上であってもよく、１５００ｐｐｍ以上であってもよい。上限は特に制限がないが、４６００ｐｐｍ以下であってよく、４５００ｐｐｍ以下であってよい。
　温度が０℃の場合、水分が２０００ｐｐｍ以上であってもよく、３０００ｐｐｍ以上であってもよい。上限は特に制限がないが、６１００ｐｐｍ以下であってよく、６０００ｐｐｍ以下であってよい。
　温度が１５℃の場合、水分が５０００ｐｐｍ以上であってもよく、６０００ｐｐｍ以上であってもよい。上限は特に制限がないが、１７２００ｐｐｍ以下であってよく、１７１００ｐｐｍ以下であってよい。
　温度が２０℃の場合、水分が１００００ｐｐｍ以上であってもよく、１５０００ｐｐｍ以上であってもよい。上限は特に制限がないが、２５０００ｐｐｍ以下であってよく、２３０００ｐｐｍ以下であってよい。
　温度が３０℃の場合、水分が２００００ｐｐｍ以上であってもよく、２２０００ｐｐｍ以上であってもよい。上限は特に制限がないが、４４０００ｐｐｍ以下であってよく、４３０００ｐｐｍ以下であってよい。
　温度が４０℃の場合、水分が３５０００ｐｐｍ以上であってもよく、４００００ｐｐｍ以上であってもよい。上限は特に制限がないが、７５０００ｐｐｍ以下であってよく、７００００ｐｐｍ以下であってよい。 Since the amount of saturated water vapor varies depending on the temperature, the moisture content may be 80 ppm or more, or 85 ppm or more, at −40° C. There is no particular upper limit, but it may be 188 ppm or less, or 185 ppm or less.
When the temperature is −4° C., the moisture content may be 1000 ppm or more, or 1500 ppm or more. There is no particular upper limit, but the moisture content may be 4600 ppm or less, or 4500 ppm or less.
When the temperature is 0° C., the moisture content may be 2000 ppm or more, or 3000 ppm or more. There is no particular upper limit, but the moisture content may be 6100 ppm or less, or 6000 ppm or less.
When the temperature is 15° C., the moisture content may be 5000 ppm or more, or 6000 ppm or more. There is no particular upper limit, but the moisture content may be 17200 ppm or less, or 17100 ppm or less.
When the temperature is 20° C., the moisture content may be 10,000 ppm or more, or 15,000 ppm or more. There is no particular upper limit, but the moisture content may be 25,000 ppm or less, or 23,000 ppm or less.
When the temperature is 30° C., the moisture content may be 20,000 ppm or more, or 22,000 ppm or more. There is no particular upper limit, but the moisture content may be 44,000 ppm or less, or 43,000 ppm or less.
When the temperature is 40° C., the moisture content may be 35,000 ppm or more, or 40,000 ppm or more. There is no particular upper limit, but the moisture content may be 75,000 ppm or less, or 70,000 ppm or less.
　水分量としては、相対湿度で７５％以上であってよく、９０％以上であってもよい。 The moisture content may be 75% or more, or 90% or more, in terms of relative humidity.
　本発明のエチレン分解方法は、白金族元素担持シリカゲルから３０ｃｍ以内の気体におけるアルコール量が、白金族元素担持シリカゲル１ｇあたり、所期の効果を発揮させる観点から、アルコールを２５０ｐｐｍ以上用いることが好ましい。３００ｐｐｍ以上がより好ましく、５００ｐｐｍ以上がさらに好ましく、８００ｐｐｍ以上が特に好ましく、１０００ｐｐｍ以上が最も好ましい。上限は特段に制限がないが、経済性の観点から、２０００００ｐｐｍ以下が好ましく、１５００００ｐｐｍ以下がより好ましく、１０００００ｐｐｍ以下が更に好ましく、８０００ｐｐｍ以下が殊更に好ましく、７０００ｐｐｍ以下が特に好ましく、６０００ｐｐｍ以下が最も好ましい。
　本発明のエチレン分解方法において、白金族元素担持シリカゲルは、エチレンを含む空間体積１００Ｌあたり、所期の効果を発揮させる観点から、０．５ｇ以上用いることが好ましい。１ｇ以上がより好ましく、２ｇ以上がさらに好ましく、１ｇ以上が最も好ましい。材料の価格の観点から、１０ｇ以下が好ましく、８ｇ以下がより好ましく、５ｇ以下がさらに好ましい。 In the ethylene decomposition method of the present invention, the amount of alcohol in the gas within 30 cm from the platinum group element-supported silica gel is preferably 250 ppm or more per gram of the platinum group element-supported silica gel from the viewpoint of exerting the intended effect. More preferably, it is 300 ppm or more, even more preferably, it is 500 ppm or more, particularly preferably, it is 800 ppm or more, and most preferably, it is 1000 ppm or more. There is no particular upper limit, but from the viewpoint of economic efficiency, it is preferably 200000 ppm or less, more preferably, it is 150000 ppm or less, even more preferably, it is 100000 ppm or less, particularly preferably, it is 8000 ppm or less, particularly preferably, it is 7000 ppm or less, and most preferably, it is 6000 ppm or less.
In the ethylene decomposition method of the present invention, from the viewpoint of achieving the intended effect, the platinum group element-supported silica gel is preferably used in an amount of 0.5 g or more per 100 L of space volume containing ethylene, more preferably 1 g or more, even more preferably 2 g or more, and most preferably 1 g or more. From the viewpoint of the cost of the material, the amount is preferably 10 g or less, more preferably 8 g or less, and even more preferably 5 g or less.
　以下に、実施例により本発明を具体的に説明するが、本発明はこれらの実施例によって何ら限定されるものではない。 The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples in any way.
＜製造例１＞
（シリカゲルＡの製造）
　ガラス製で、上部に大気開放の水冷コンデンサが取り付けてある５Ｌセパラブルフラスコ（ジャケット付き）に、純水１０００ｇを仕込んだ。８０ｒｐｍで撹拌しながら、これにテトラメトキシシラン１４００ｇを３分間かけて仕込んだ。水／テトラメトキシシランのモル比は６である。セパラブルフラスコのジャケットには５０℃の温水を通水した。引き続き撹拌を継続し、内容物が沸点に到達した時点で、撹拌を停止した。引き続き約０．５時間、ジャケットに５０℃の温水を通水して生成したゾルをゲル化させた。その後、速やかにゲルを取り出し、目開き６００ミクロンのナイロン製網を通してゲルを粉砕し、粉体状のウェットゲル（シリカヒドロゲル）を得た。このシリカヒドロゲル４５０ｇと純水４５０ｇを１Ｌのガラス製オートクレーブに仕込み、１３０℃で３時間の水熱処理を実施した。当該水熱処理の後、Ｎｏ．５Ａ濾紙で濾過し、濾滓を水洗することなく１００℃で恒量となるまで減圧乾燥し、シリカゲルＡを得た。なお、シリカゲルＡの、細孔容積、ＢＥＴ比表面積、平均細孔直径を下記の方法により測定した。得られた結果を表１に示す。 <Production Example 1>
(Production of Silica Gel A)
1000g of pure water was charged into a 5L separable flask (jacketed) made of glass and equipped with a water-cooled condenser open to the atmosphere at the top. 1400g of tetramethoxysilane was charged into the flask over 3 minutes while stirring at 80 rpm. The molar ratio of water/tetramethoxysilane was 6. Hot water at 50°C was passed through the jacket of the separable flask. Stirring was continued, and when the contents reached the boiling point, the stirring was stopped. Hot water at 50°C was passed through the jacket for about 0.5 hours to gel the sol produced. The gel was then quickly taken out and crushed through a nylon net with a mesh size of 600 microns to obtain a powdered wet gel (silica hydrogel). 450g of this silica hydrogel and 450g of pure water were charged into a 1L glass autoclave and subjected to hydrothermal treatment at 130°C for 3 hours. After the hydrothermal treatment, No. The mixture was filtered through No. 5A filter paper, and the filter cake was dried under reduced pressure at 100°C until a constant weight was obtained without washing with water, to obtain Silica Gel A. The pore volume, BET specific surface area, and average pore diameter of Silica Gel A were measured by the following methods. The obtained results are shown in Table 1.
＜製造例２＞
（白金族元素担持シリカゲルＡの製造）
　製造例１で得られたシリカゲルＡ１００質量％に対して白金の量が１質量％になるように処理し、白金族元素担持シリカゲルＡを得た。 <Production Example 2>
(Preparation of Platinum Group Element-Supported Silica Gel A)
Silica gel A obtained in Production Example 1 was treated so that the amount of platinum was 1% by mass relative to 100% by mass of the silica gel A obtained in Production Example 1, thereby obtaining silica gel A carrying a platinum group element.
＜製造例３＞
（白金族元素担持シリカゲルＢの製造）
　富士シリシア社製ＣＡＲｉＡＣＴ　Ｇ（Ｇ－６）１００質量％に対して白金の量が１質量％になるように処理し、白金族元素担持シリカゲルＢを得た。 <Production Example 3>
(Production of Platinum Group Element-Supported Silica Gel B)
100% by mass of CARiACT G (G-6) manufactured by Fuji Silysia Chemical Ltd. was treated so that the amount of platinum was 1% by mass, thereby obtaining platinum group element-supported silica gel B.
［測定方法］
（エチレン濃度のガスクロマトグラフィーによる測定）
＜測定条件＞
装置    Ａｇｉｌｅｎｔ　ＧＣ８８６０
カラム  ＰｏｒａＢＯＮＤ－Ｑ　２５ｍ×３２０μｍ×５μｍ
温度    ６０℃　（５ｍｉｎ）
注入口温度     １２０℃
キャリアガス   Ｈｅ　３．５０２ｍＬ／ｍｉｎ　（ｃｏｎｓｔａｎｔ　ｆｌｏｗ）
スプリット比   ５０：１
検出器  ＦＩＤ　（１５０℃）
測定タイミング　０．２５、１、２、３、４、５、６、２４時間後 [Measuring method]
(Measurement of ethylene concentration by gas chromatography)
<Measurement conditions>
Equipment: Agilent GC8860
Column: PoraBOND-Q 25m x 320μm x 5μm
Temperature: 60°C (5 min)
Injection port temperature: 120°C
Carrier gas: He 3.502 mL/min (constant flow)
Split ratio 50:1
Detector: FID (150°C)
Measurement timing: 0.25, 1, 2, 3, 4, 5, 6, 24 hours
＜実施例１＞
（エチレン分解試験）
　あらかじめ１５０℃で３時間乾燥させた製造例２により得られた白金族元素担持シリカゲルＡ０．３ｇと２３％硫酸水溶液４５ｇを、アルミニウムバック（３Ｌ、厚さ２５μｍ）に入れ、乾燥空気を２．５Ｌ充填した後、エタノールを１０００ｐｐｍ注入したのち、メイクアップガス（組成：エチレン＝１００ｐｐｍ、Ｏ２＝２０％、Ｎ２＝バランス）を１３０ｍＬ注入し、エチレンの濃度が５ｐｐｍとなるよう調製した。硫酸水溶液はガラスビーカー、白金族元素担持シリカゲルＡはシャーレに入れており、いずれの容器も上部を開放した。環境温度２５℃で、０．２５、１、２、３、４、５、６、２４時間後のエチレン濃度をセンサーガスクロマトグラフ（ＮＩＳＳＨＡエフアイエス株式会社、型番：ＳＧＥＡ－Ｐ３－Ｃ１）で測定した。なお、上記の硫酸水溶液は、相対湿度を８５％に保つためのものである。得られた結果を図１及び表１に示す。 Example 1
(Ethylene decomposition test)
0.3 g of platinum group element-supported silica gel A obtained in Production Example 2, which had been dried at 150° C. for 3 hours in advance, and 45 g of 23% aqueous sulfuric acid solution were placed in an aluminum bag (3 L, thickness 25 μm), and 2.5 L of dry air was filled, after which 1000 ppm of ethanol was injected, and then 130 mL of make-up gas (composition: ethylene=100 ppm, O 2 =20%, N 2 =balance) was injected to adjust the ethylene concentration to 5 ppm. The aqueous sulfuric acid solution was placed in a glass beaker, and the platinum group element-supported silica gel A was placed in a petri dish, with the tops of both containers open. At an environmental temperature of 25° C., the ethylene concentrations after 0.25, 1, 2, 3, 4, 5, 6, and 24 hours were measured using a sensor gas chromatograph (Nissha FIS Co., Ltd., model number: SGEA-P3-C1). The above aqueous sulfuric acid solution was used to maintain a relative humidity of 85%. The results are shown in FIG.
＜比較例１＞
　エタノールを添加せず、白金族元素担持シリカゲルＡの量を０．４ｇに変更した以外は、実施例１と同様の条件でエチレン分解試験を行った。得られた結果を図１及び表２に示す。 <Comparative Example 1>
Except for not adding ethanol and changing the amount of platinum group element-supporting silica gel A to 0.4 g, an ethylene decomposition test was carried out under the same conditions as in Example 1. The obtained results are shown in FIG.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　白金族元素担持シリカゲルＡにエタノールが共存した実施例１と、エタノールが共存していない比較例１とを比較すると、６時間後のエチレン濃度が、比較例１では１９４１ｐｐｂであるのに対して、実施例１では４９６ｐｐｂとなっており、実施例１は比較例１に対して約４倍もエチレン分解速度が速いことが分かる。また、２４時間後のエチレン濃度を比較しても、比較例１では１６６ｐｐｂであるのに対して、実施例１では９２ｐｐｂとなっており、実施例１は比較例１に対して１．８倍以上エチレン分解速度が速いことが分かる。この結果から、白金族元素担持シリカゲルにアルコールを共存させることにより、高湿度下においても、エチレン分解速度を高くできること、また、水分が存在してもエチレン分解性能が低下しにくいことが分かる。 Comparing Example 1, in which ethanol coexists with platinum group element-supported silica gel A, with Comparative Example 1, in which ethanol does not coexist, the ethylene concentration after 6 hours is 1941 ppb in Comparative Example 1, while it is 496 ppb in Example 1, indicating that the ethylene decomposition rate of Example 1 is about four times faster than that of Comparative Example 1. Also, when comparing the ethylene concentration after 24 hours, it is 166 ppb in Comparative Example 1, while it is 92 ppb in Example 1, indicating that the ethylene decomposition rate of Example 1 is more than 1.8 times faster than that of Comparative Example 1. From these results, it is clear that by causing alcohol to coexist with platinum group element-supported silica gel, the ethylene decomposition rate can be increased even under high humidity conditions, and that the ethylene decomposition performance is less likely to decrease even in the presence of moisture.
＜実施例１―２＞
（エチレン分解試験）
　エチレン濃度をガスクロマトグラフィーにより測定したほかは、実施例１と同様に試験を行った。得られた結果を図２及び表３に示す。なお、６時間後のエチレン濃度は測定しなかった。 <Example 1-2>
(Ethylene decomposition test)
Except for the measurement of the ethylene concentration by gas chromatography, the test was carried out in the same manner as in Example 1. The obtained results are shown in Figure 2 and Table 3. Note that the ethylene concentration after 6 hours was not measured.
＜比較例２＞
　白金族元素担持シリカゲルＡの量を０．３ｇに変更し、エチレン濃度をガスクロマトグラフィーにより測定した以外は、比較例１と同様の条件でエチレン分解試験を行った。得られた結果を図２及び表３に示す。なお、６時間後のエチレン濃度は測定しなかった。 <Comparative Example 2>
An ethylene decomposition test was carried out under the same conditions as in Comparative Example 1, except that the amount of platinum group element-supported silica gel A was changed to 0.3 g and the ethylene concentration was measured by gas chromatography. The results are shown in Figure 2 and Table 3. The ethylene concentration after 6 hours was not measured.
＜実施例２＞
（エチレン分解試験）
　白金族元素担持シリカゲルＡの代わりに株式会社フルヤ金属社製ＦＴ－ｅｃｏ触媒を用いたほかは、実施例１―２と同様に試験を行った。得られた結果を図３及び表３に示す。なお、ＦＴ－ｅｃｏ触媒は、白金族元素担持シリカゲルである。 Example 2
(Ethylene decomposition test)
The test was carried out in the same manner as in Example 1-2, except that FT-eco catalyst manufactured by Furuya Metal Co., Ltd. was used instead of platinum group element-supported silica gel A. The obtained results are shown in FIG. 3 and Table 3. The FT-eco catalyst is a platinum group element-supported silica gel.
＜比較例３＞
（エチレン分解試験）
　白金族元素担持シリカゲルＡの代わりに株式会社フルヤ金属社製ＦＴ－ｅｃｏ触媒を用いたほかは、比較例２と同様に試験を行った。得られた結果を図３及び表３に示す。 <Comparative Example 3>
(Ethylene decomposition test)
The test was carried out in the same manner as in Comparative Example 2, except that FT-eco catalyst manufactured by Furuya Metal Co., Ltd. was used instead of platinum group element-supported silica gel A. The obtained results are shown in FIG.
＜実施例３＞
（エチレン分解試験）
　白金族元素担持シリカゲルＡの代わりに白金族元素担持シリカゲルＢを用いたほかは、実施例１―２と同様に試験を行った。得られた結果を図４及び表３に示す。 Example 3
(Ethylene decomposition test)
The test was carried out in the same manner as in Example 1-2, except that platinum group element-supported silica gel B was used instead of platinum group element-supported silica gel A. The obtained results are shown in FIG.
＜比較例４＞
（エチレン分解試験）
　白金族元素担持シリカゲルＡの代わりに白金族元素担持シリカゲルＢを用いたほかは、比較例２と同様に試験を行った。得られた結果を図４及び表３に示す。
Figure JPOXMLDOC01-appb-T000003
 <Comparative Example 4>
(Ethylene decomposition test)
The test was carried out in the same manner as in Comparative Example 2, except that platinum group element-supported silica gel B was used instead of platinum group element-supported silica gel A. The obtained results are shown in FIG.
Figure JPOXMLDOC01-appb-T000003
　白金族元素担持シリカゲルにエタノールが共存した実施例２～３とエタノールが共存していない比較例３～４とを比較すると、実施例１及び１－２と、比較例１及び２の比較と同様に、エタノールを共存させた場合に、エチレン分解速度が速いことが分かる。この結果からも、白金族元素担持シリカゲルにアルコールを共存させることにより、高湿度下においても、エチレン分解速度を高くできること、また、水分が存在してもエチレン分解性能が低下しにくいことが分かる。 Comparing Examples 2-3, in which ethanol coexists with the platinum group element-supported silica gel, to Comparative Examples 3-4, in which ethanol does not coexist, it can be seen that the ethylene decomposition rate is faster when ethanol is coexistent, just as in the comparison between Examples 1 and 1-2 and Comparative Examples 1 and 2. This result also shows that by allowing alcohol to coexist with platinum group element-supported silica gel, the ethylene decomposition rate can be increased even under high humidity conditions, and that the ethylene decomposition performance is less likely to decrease even in the presence of moisture.
　本発明の、エチレン分解剤、鮮度保持剤、及びそれらを備えた物品、並びにその利用は、植物から放出されるエチレンの分解に好適に用いられ、植物の鮮度を維持しうるものである。

  The ethylene decomposing agent, freshness preserving agent, and article comprising them, as well as use of the same, of the present invention are suitably used for decomposing ethylene released from plants, and can maintain the freshness of the plants.

Claims (19)

  1. 　白金族元素担持シリカゲルを含み、アルコール共存条件下でエチレンを分解するための、エチレン分解剤。 An ethylene decomposition agent that contains silica gel carrying a platinum group element and is used to decompose ethylene in the presence of alcohol.
  2. 　前記アルコールがアルコール徐放剤から放出される、請求項１に記載のエチレン分解剤。 The ethylene decomposition agent according to claim 1, wherein the alcohol is released from an alcohol sustained release agent.
  3. 　前記アルコールが液体または気体である、請求項１に記載のエチレン分解剤。 The ethylene decomposition agent according to claim 1, wherein the alcohol is a liquid or a gas.
  4. 　白金族元素担持シリカゲルとアルコールとを含む、エチレン分解剤。 An ethylene decomposition agent comprising platinum group element-supported silica gel and alcohol.
  5. 　白金族元素担持シリカゲルとアルコールとがそれぞれ別個に分包されている、請求項４に記載のエチレン分解剤。 The ethylene decomposition agent according to claim 4, in which the platinum group element-supported silica gel and the alcohol are each packed separately.
  6. 　アルコールがアルコール徐放剤を含む、請求項４に記載のエチレン分解剤。 The ethylene decomposition agent according to claim 4, wherein the alcohol contains an alcohol sustained release agent.
  7. 　白金族元素担持シリカゲルを含み、アルコール共存条件下で用いる、植物の鮮度保持剤。 A freshness-preserving agent for plants that contains silica gel carrying platinum group elements and is used in the presence of alcohol.
  8. 　前記アルコールがアルコール徐放剤から放出される、請求項７に記載の植物の鮮度保持剤。 The plant freshness preserving agent according to claim 7, wherein the alcohol is released from an alcohol sustained release agent.
  9. 　前記アルコールが液体または気体である、請求項７に記載の植物の鮮度保持剤。 The plant freshness preserving agent according to claim 7, wherein the alcohol is a liquid or a gas.
  10. 　白金族元素担持シリカゲルとアルコールとを含む、植物の鮮度保持剤。 A freshness-preserving agent for plants that contains platinum group elements-supported silica gel and alcohol.
  11. 　白金族元素担持シリカゲルとアルコールとがそれぞれ別個に分包されている、請求項１０に記載の植物の鮮度保持剤。 The plant freshness preservation agent according to claim 10, in which the platinum group element-supported silica gel and the alcohol are each packaged separately.
  12. 　アルコールがアルコール徐放剤を含む、請求項１０に記載の植物の鮮度保持剤。 The freshness-preserving agent for plants according to claim 10, wherein the alcohol contains an alcohol-releasing agent.
  13. 　白金族元素担持シリカゲルとアルコール発生源を含むエチレン分解デバイス。 An ethylene decomposition device containing silica gel carrying a platinum group element and an alcohol generating source.
  14. 　前記アルコール発生源がアルコール徐放剤を含む、請求項１３に記載のエチレン分解デバイス。 The ethylene decomposition device of claim 13, wherein the alcohol generating source includes an alcohol sustained release agent.
  15. 　前記アルコール発生源が噴霧器である、請求項１３に記載のエチレン分解デバイス。 The ethylene decomposition device of claim 13, wherein the alcohol generating source is a sprayer.
  16. 　白金族元素担持シリカゲルと、アルコールを共存させるエチレン分解方法。 A method for decomposing ethylene using platinum group element-supported silica gel in the presence of alcohol.
  17. 　請求項１～６いずれかに記載のエチレン分解剤、請求項７～１２いずれかに記載の植物の鮮度保持剤、又は請求項１３～１５いずれかに記載のエチレン分解デバイスを備える、物品。 An article comprising an ethylene decomposition agent according to any one of claims 1 to 6, a plant freshness preservation agent according to any one of claims 7 to 12, or an ethylene decomposition device according to any one of claims 13 to 15.
  18. 　袋、容器、フィルター、冷蔵庫、冷凍庫、コンテナ、空調機、車両、船舶、又は航空機である、請求項１７に記載の物品。 The article of claim 17, which is a bag, a container, a filter, a refrigerator, a freezer, a container, an air conditioner, a vehicle, a ship, or an aircraft.
  19. 　白金族元素担持シリカゲルとアルコールの共存条件下に、植物を保存することを含む、植物の鮮度保持方法。
     

          A method for preserving the freshness of a plant, comprising storing the plant in the presence of platinum group element-supported silica gel and alcohol.
PCT/JP2023/043169 2022-12-01 2023-12-01 Ethylene decomposer, freshness preserver, article comprising ethylene decomposer or freshness preserver, and use for same WO2024117263A1 (en)

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