COMPOSITION OF PHOSPHINE MIXTURE FOR FUMIGATION, METHOD OF ITS PRODUCTION, AND METHOD OF FUMIGATION

Abstract

The challenge of this product is to provide a fumigation phosphine that effectively controls clogging of the fumigation gas supply equipment piping due to impurities and exhibits low spontaneous flammability. Furthermore, it aims to provide a safe method of fumigation with phosphine, reducing the possibility of clogging the fumigation gas supply equipment piping and spontaneous ignition. The fumigation phosphine of this product has a P₄ content of 10 ppm by mass or less and a water content of 10 ppm by mass or less. The fumigation method of this product consists of fumigating the object to be fumigated using a phosphine with a P₄ content of 10 ppm by mass or less and a water content of 10 ppm or less. Claim 1: A fumigation phosphine, characterized in that it has a P₄ content of 10 ppm by mass or less and a water content of 10 ppm or less.Claim 2: The fumigation phosphine according to claim 1, characterized in that it has a diphosphine content of 100 ppm by mass or less. Claim 4: A method for producing the fumigation phosphine, characterized in that it comprises a refining step for removing water after the removal of P₄ contained in the phosphine. Claim 7: A fumigation method for fumigating an object to be fumigated using a phosphine with a P₄ content of 10 ppm by mass or less and a water content of 10 ppm by mass or less. Claim 8: The fumigation method according to claim 7, characterized in that the object to be fumigated is at least one type selected from cultivated plants, foodstuffs other than cultivated plants, soil, buildings, and cultural heritage.

Description

PHOSPHINE FOR FUMIGATION AND METHOD OF ITS PRODUCTION, AND METHOD FUMIGATION [Technical Field J [0001J The present invention relates to a phosphine for fumigation and to a fumigation method that 1.a uses, |Prior Technique|

[0002] Phosphine is a compound represented by PHj. Phosphine has an excellent insecticidal effect and is used as a fumigant.

[0003] Phosphine is generally produced by a method in which yellow phosphorus (the main component: Pj) and an alkali react; a method in which yellow phosphorus is subjected to high-temperature hydrolysis; a method in which a phosphorus-metal compound, for example, aluminum phosphide or zinc phosphide, is reacted with water or acid; a method in which yellow phosphorus is electrolytically reduced; a method in which yellow phosphorus is electrolytically reduced using zinc, cadmium, or amalgam; a method in which yellow phosphorus is heated to convert it to red phosphorus, and this yellow phosphorus is then contacted with water in phosphoric acid; and other similar methods. However, it is known that phosphine prior to refining (hereafter also referred to as crude phosphine), obtained by any of the methods IF-2020-17934125-APN-ANP#INPI Page 1 of 23 mentioned above contains impurities.

[0004] For example, Patent Document 1 states that if a low-grade hydrogenated phosphorus compound is present in crude phosphine, it deposits a tarry or yellow powder on the inner wall of valves, etc., obstructing them and creating an operational hazard. It also states that activated carbon is used to remove this low-grade hydrogenated phosphorus compound. Furthermore, Patent Document 2 states that to obtain high-purity phosphine for semiconductor manufacturing, water is removed from the phosphine using a zeolite. [List of Appointments] [Patent Documents] [0005 | [Patent Document 1] Patent Application Publication Not Examined in Japan with IP S58-49608 [Patent Document 2| Patent Application Publication] Not Examined in Japan with No. H62-138313 [Summary of the Invention]

[0006] The phosphine from which the low-grade hydrogenated phosphorus compound was removed using activated carbon as mentioned in Patent Document 1, even when used for fumigation, presented a problem of IF-2020-17934125-APN-ANP#INPI Page 2 of 23. A solid deposit forms inside the piping of the fumigation gas supply equipment, causing obstruction or scale formation within the piping or valves of the same equipment. Furthermore, the high-purity phosphine mentioned in Patent Document 2 does not cause obstruction due to its high purity, but its price is high. Therefore, a phosphine with cost-effective efficiency for fumigation is being sought. Additionally, it is stated that both phosphine itself and its impurities cause spontaneous combustion. Consequently, a phosphine with low spontaneous flammability is required for fumigation safety.

[0007] The challenge of the present invention is to provide a phosphine for fumigation that exhibits effective control of obstruction and scale formation in pipes and valves, resulting from impurities, and low spontaneous flammability.

[0008] The inventor of the present invention, as a result of intensive studies to solve the aforementioned challenge, discovered that the same challenge can be solved by ensuring that both the amount of Pj and the amount of water do not exceed predetermined values, and thus arrived at the completion of the present invention. [ 0 0 0 9] More specifically, the present invention is for providing a phosphine for fumigation with a P4 content of 10 ppm by mass or less and a water content of 10 ppm by mass IF-2020-17934125-APN-ANP#INPI Page 3 of 23 or less. [00101 Furthermore, the present invention is for providing a fumigation method for fumigating an object to be fumigated using a phosphine with a Pi content of 10 ppm by mass or less and a water content of 10 ppm by mass or less. [Mode of Implementation of the Invention[ [0011 ] A preferred embodiment of the present invention is described below. The phosphine used in the present invention is a compound represented by PHj. The phosphine may be in any state from solid to liquid to gas. The phosphine is distributed and / or stored, for example, in a liquid state in a pressure-resistant container, and is used in a gaseous state for fumigation.

[0012] The inventor of the present invention conducted intensive studies on the cause of pipe obstruction in fumigation gas supply equipment caused by traditional fumigation phosphine. As a result, it was discovered that the occurrence of pipe obstruction is related to the amount of phosphine contained in the phosphine. The reason for this is not clear, but it is inferred that it is because the deposit formed inside the pipe consists of Pd or a component contained in the phosphine as an impurity. This component is solid hydrogen phosphide, which exhibits behavior similar to Pj and, upon decomposition, becomes P4. The inventor of the present IF-2020-17934125-APN-ANP#INPI Page 4 of 23 of the invention considers that pipe obstruction can be prevented by reducing the amount of P4 as an index of impurities contained in the phosphine. Furthermore, the inventor of the present invention discovered that spontaneous flammability can be reduced by decreasing the amount of P4 and at the same time the amount of water as mentioned below.

[0013] The inventor of the present invention infers that P4 occurs as a solid in liquid phosphine and as a vapor or mist in phosphine gas. It is inferred that P4 occurs mixed with phosphine, originating from the raw material used in the manufacture of phosphine. Furthermore, as mentioned above, the inventor of the present invention considers that Pj can also be generated from the further decomposition of the aforementioned solid hydrogen phosphide. I0014 ] From the standpoint of pipe clogging control and spontaneous combustion control, the P4 content in phosphine is 10 ppm by mass or less, and preferably 5 ppm by mass or less. It is preferable that P4 not be substantially contained in the phosphine, but from the standpoint of the manufacturing cost of phosphine for fumigation, it is preferable that the content be 0.1 ppm by mass or more. The amount referred to here represents the ratio with respect to phosphine (PH3).

[0015] The inventor of the present invention discovered that it is also important, in addition to reducing the amount of P4 contained in the phosphine, to decrease the amount of water IF-2020-17934125-APN-ANP#INPI Page 5 of 23 contained in the phosphine to control the obstruction of the phosphine pipe and to control spontaneous combustion. The reason for this is not clear, but there may be a case where the phosphine reacts with water, becoming P4o in solid hydrogen phosphide which exhibits behavior similar to that of Pi, and therefore, by ensuring that the amount of water contained in the phosphine does not exceed a predetermined value, the occurrence of such a reaction can be prevented. The inventor of the present invention considers that, due to the above, the occurrence of pipe obstruction resulting from the deposition of a solid can be effectively controlled, and spontaneous combustion reduced. [0016 | From the standpoint of pipe and valve clogging control and spontaneous combustion control, the Pj content in phosphine is 10 ppm by mass or less, and preferably 5 ppm by mass or less. The less water contained in the phosphine, the more preferable, but from the standpoint of phosphine manufacturing cost, it is preferable that the same amount be 0.1 ppm by mass or more. The amount of water referred to here represents the ratio with respect to phosphine (PFh).

[0017] To ensure that the P4 and water content of the phosphine for fumigation do not exceed the aforementioned upper limits, a specific refining method, described below, can be applied to the crude phosphine. IF-2020-17934125-APN-ANP#INPI Page 6 of 23 Production of crude phosphine, which serves as the raw material for phosphine for fumigation, can be employed by any method between: a method in which yellow phosphorus and an alkali are reacted with each other; a method in which yellow phosphorus is subjected to hydrolysis at high temperature; a method in which a compound between a metal and phosphorus, for example, aluminum phosphide, zinc phosphide, is reacted with water or acid; a method in which yellow phosphorus is electrolytically reduced; a method in which yellow phosphorus is electrolytically reduced using zinc, cadmium or amalgam; a method in which yellow phosphorus is heated to convert it to red phosphorus, and this red phosphorus is contacted with water in phosphoric acid; and other similar methods. Phosphine is preferably produced by reacting yellow phosphorus and an alkali with each other. The method in which yellow phosphorus and an alkali are made to act upon each other can be any of (1) and (2): (1) P4+ 3NaOH + -> 3PHj + 3NaH2PO2¢2) P4+ 4H2O + 2NaOH -> 2PiIj + 2NaH2PO3[0018 | Traditional fumigation phosphine was produced by contacting aluminum phosphide or zinc phosphide with water and was used directly in fumigation. Alternatively, crude phosphine produced by either of the aforementioned methods was used after being refined simply with activated carbon or zeolite. The traditional fumigation phosphine mentioned here showed water and P4 content exceeding the limit values. IF-2020-17934125-APN-ANP#INPI Page 7 of 23 superiors mentioned above. [0019 1 To ensure that the Pt and water content in the festine used in the present invention do not exceed the aforementioned upper limits, a combined method may be applied, such as, for example, a method in which P4 is adsorbed and removed from the crude festine obtained by each of the aforementioned methods using activated carbon or zeolite; a method in which the festine is dehydrated by cooling to or below freezing; and a method in which the phosphine is dehydrated using silica gel or zeolite. Furthermore, the above-mentioned methods may be combined with a method in which the crude phosphine obtained by each of the aforementioned methods is washed with water. After applying the water washing method, drying is necessary; however, except for this point, there is no particular specification regarding the order of these methods.

[0020] As mentioned previously, there is a possibility that phosphine will react upon contact with water, converting to solid hydrogen phosphide (P4O), which exhibits behavior similar to that of P4. Therefore, the prior removal of water from the phosphine allows for the control of secondary production of solid hydrogen phosphide (P4O). However, the zcolite and silica gel mentioned above, used for phosphine dehydration, have pores that function to remove water, and the presence of solid hydrogen phosphide (P4O) in the phosphine, by sealing the pores, IF-2020-17934125-APN-ANP#INPI Page 8 of 23. These pores carry the possibility that sufficient dehydration effects may be difficult to achieve. Furthermore, the accumulation of P4O from solid hydrogen phosphide raises the possibility of easy ignition. From this point of view, it is particularly preferable that the adsorption and rapid removal of Pi contained in the phosphine precede the dehydration of the phosphine, as this can extend the life of the silica gel and zeolite used for dehydration, and can also increase the safety of the process.

[0021] Regarding the zeolite, there is no particular specification, and any natural or synthetic zeolite can be used. Examples of natural zeolites include: Analcime: SiO2 / Al2O3 = 3.6 - 5.6; Cabazite: SiO2 / Al2O3 = 3.2 - 6.0; Clinoptilolite: SiO2 / Al2O3 = 8.5 - 10.5; Erionite: SiO2 / Al2O3 = 5.8 - 7.4; Paujasite: SiO2 / Al2O3 = 4.2 - 4.6; Mordenite: SiO2 / Al2O3 = 0.34 - 10.0; Phillipsite: SiO2 / Al2O3 = 2.6 - 4.4. As examples of synthetic zeolites, we can cite, for instance, zeolite type A: SiO2 / Al2O3 = 1.4 - 2.4; zeolite type X: SiO2 / Al2O3 = 2-3; zeolite type Y: SiO2 / Al2O3 = 3 ~ 6. With regard to particle size, the specific surface area is preferably 150 m2 / g or more, and the average particle size is preferably 0.1 - 100 pm, and more preferably 0.1 5 0 pm,

[0022] For the aforementioned activated carbon, there is no particular specification, and one can cite, for example, activated carbon derived from minerals such as coal, pitch, or coal. IF-2020-17934125-APN-ANP#INPI Page 9 of 23 of petroleum, tar; activated carbon derived from plants, such as palm husks, wood, bamboo materials; activated carbon using resins as raw materials, such as phenolic resin, melamine resin, polyimide resin, polyester resin; and activated carbon composed of a molecular sieve of carbon. Regarding the form of activated carbon, examples include powdered activated carbon; granular activated carbon; crushed activated carbon; and fibrous activated carbon. The specific surface area of ​​activated carbon is preferably 150 m² / g or more, and more preferably 300 m² / g or more. [□□23] As mentioned above, silica gel can be any amorphous silica gel other than silica sol, and examples include silica gel conforming to JIS Z0701; fine silicic acid powder such as white carbon, obtained by the wet method; fine silicic acid powder such as Aerosil, obtained by the dry method; powder derived from the silicon or ferrosilicon production process*; or naturally occurring ganister. Regarding particle size, the specific surface area is preferably 150 nf / g or greater, and the average particle size is preferably 0.1–100 µm, and more preferably 0.1–50 µm. The amount of diphosphine, which is a type of impurity contained in the phosphine used in the present invention, preferably does not exceed the specified level. Diphosphine is a compound represented by H^P^. Diphosphine, when IF-2020-17934125-APN-ANP#INPI Page 10 of 23. Upon decomposition, it can produce solid hydrogenated phosphorus that exhibits behavior similar to that of r4. Therefore, the amount of phosphine employed in the present invention preferably has a diphosphine content of 100 ppm by mass or less, more preferably 70 ppm by mass or less, even more preferably 50 ppm by mass or less, and most preferably 30 ppm by mass or less. The amount of diphosphine is preferably 1 ppm by mass or more for ease of phosphine production. The amount of diphosphine represents the ratio with respect to phosphine (PH3). [OOΞ5] To ensure that the amount of diphosphine does not exceed the aforementioned upper limits, a method similar to the refining method described above is required to prevent, for example, the amount of water and the amount of Na from exceeding the aforementioned upper limits.

[0026] In the present invention, the amounts of water, Pi, and diphosphine contained in phosphine are all measured with the phosphine in the gaseous state. The amount of water contained in the phosphine is measured using the Karl Fischer method. The amount of P4 is measured using the colorimetric method with phosphovanadomolybdate. The amount of diphosphine is measured using nuclear magnetic resonance. In the phosphine used in the present invention, impurities other than water, P4, and diphosphine mentioned above are also preferably contained in an amount IF-2020-17934125-APN-ANP#INPI Page 11 of 23 as reduced as possible. More specifically, in phosphine, the amount of Ib contained is preferably 100 ppm by mass or more and 10,000 ppm by mass or less, and more preferably Ξ00 ppm by mass or more and 9,000 ppm by mass or less. The amount is preferably 1 ppm by mass or more and 500 ppm by mass or less, and more preferably 10 ppm by mass or more and 300 ppm by mass or less. The amount of O2 is preferably 0.1 ppm by mass or more and 50 ppm by mass or less, and more preferably 0.5 ppm by mass or more and 30 ppm by mass or less. The amount of AsH.·? is preferably 1 ppm by mass or more and 500 ppm by mass or less, and more preferably 10 ppm by mass or more and 300 ppm by mass or less. The amount of CO2 is preferably 0.01 ppm by mass or more and 1 ppm by mass or less, and more preferably 0.05 ppm by mass or more and 0.5 ppm by mass or less. Phosphine for fumigation with impurity levels within the limits mentioned above is preferable because it allows for an attempt to achieve compatibility between production cost, ease of production, and safety. The amount of these impurities represents the quantity relative to phosphine and can be measured, for example, by gas chromatography or atomic absorption spectrometry,

[0028] The purity of the phosphine used in the present invention is preferably 98% by mass or more, and more preferably 99% by mass or more. The purity of the phosphine is preferably 99.9% by mass or less for ease of IF-2020-17934125-APN-ANP#INPI Page 12 of 23 phosphine production. [0029J The phosphine used in the present invention, containing a reduced amount of water and Pj as mentioned above, has reduced flammability and improved handling compared to traditional phosphine. For example, the phosphine used in the present invention preferably does not spontaneously ignite when its concentration in air at a temperature of 54 <bC o menos, es superior a 1¾ en volumen, y preferiblemente 1,3¾ en volumen o más. Λ propósito, no se inflama espontáneamente cuando su concentración es superior a 1% en volumen, y 1,3¾ en volumen o más significa que no se inflama espontáneamente a una cualquier concentración superior a 1¾ en volumen y 1,3¾ en volumen o más, respectivamente, y no requiere incluir casos en que no se inflame espontáneamente a toda concentración superior a 1¾ en volumen y 1,3¾ en volumen o más.More specifically, when measuring the spontaneous ignition temperature of phosphine under atmospheric pressure according to IEC 60079-20-1 2010, the spontaneous ignition temperature is preferably above 54°C. The method described below can be used as a specific method for measuring the spontaneous ignition temperature.

[0030] In the present invention, phosphine, after being stored and distributed in a liquid state in pressure vessels such as cylinders or storage tanks, is subjected to evaporation at ambient temperature and atmospheric pressure, and is then used for fumigation. IF-2020-17934125-APN-ANP#INPI Page 13 of 23 directly or mixed with an inert gas. Carbon dioxide and nitrogen can be cited as inert gases. The mixing ratio between phosphine and the inert gas is represented by the volumetric ratio phosphine:inert gas, and is preferably 1:0.1-100, and more preferably 1:0.5-90. [I0031] In the present invention, fumigation refers to the act of bringing into contact with a gas effective in exterminating various harmful living organisms, such as mold, bacteria, and insects, the object (hereinafter, the object to be fumigated), in order to eliminate them. The object to be fumigated may include, for example, cultivated plants, non-cultivated foodstuffs, soil, buildings, and cultural heritage. Cultivated plants may be fumigated both before and after harvest. [Example of Implementation] [0032J The present invention is described in more detail below by presenting an exemplary embodiment, but the present invention is not limited to this exemplary embodiment.

[0033] <Ejampio de realización 1> 102.4 g of 25% by mass aqueous sodium hydroxide solution were added to 30 g of yellow phosphorus to react them according to the usual method, thus producing 10.5 L of a gas mixture with a volumetric ratio of phosphine:hydrogen = 1:1. This produced gas was introduced into a pressurized container, cooled by the IF-2020-17934125-APN-ANP#INPI Page 14 of 23. Immersion in liquid nitrogen at -200°C to condense the phosphine, thereby removing some of the water. Afterwards, the pressure vessel was removed from the liquid nitrogen to allow the release of uncondensed hydrogen as the temperature gradually rose to room temperature, and crude phosphine was obtained.

[0034] The crude phosphine obtained was passed through a column with an inner diameter of 40 mm and a length of 400 mm, packed with 300 ml of activated carbon (Ryujo Shirasagi G2c, Osaka Gas Chemicals Co., Ltd.), at a flow rate of 1 L / min. It was then passed through a cooling tower to cool to 10°C, and subsequently through another column with an inner diameter of 40 mm and a length of 400 mm, packed with 300 ml of silica gel type β1 (JIS E0701), at a flow rate of 1 L / min. Refined phosphine was obtained. Table 1 shows the amounts of water, P4, and diphosphine contained in the refined phosphine obtained. In addition, impurities other than water, P1, and diphosphine in the refined phosphine included H2 at 3,000 ppm by mass, and N2 of 41.2 ppm by mass, O2 of 0.94 ppm by mass, AsH2 of 100 ppm by mass and CO2 of 0.1 ppm by mass. [0035 J<Ejemplo de realización 2> Refined phosphine was obtained using the same method as in Example Implementation 1, except that crude phosphine was passed through type A zeolite (Molecular Sieve 3A, Wako Chemicals, Inc.) instead of type A silica gel. Table 1 shows the quantities of water, P / , and do IF-2020-17934125-APN-ANP#INPI Page 15 of 23 diphosphine, contained in the refined phosphine obtained. In addition, as impurities other than water, P4 and diphosphine of the refined phosphine obtained, were present at 2,950 ppm by mass, 41.8 ppm by mass, O1 at 0.95 ppm by mass, Asila at 99 ppm by mass and COa at 0.1 ppm by mass. |0036 ]<Ejemplo de realización 3> Refined phosphine was obtained using the same method as in Example 1, except that the crude phosphine obtained by the same method was passed through activated carbon and silica gel type A at a flow rate of 3 L / min. Table 1 shows the amounts of water, Ei, and diphosphine contained in the refined phosphine obtained. In addition, impurities other than water, Pi, and diphosphine in the refined phosphine included H2 at 3,100 ppm by mass, 2.2 ppm by mass, 0.1 ppm by mass, AsHs at 105 ppm by mass, and COz at 0.1 ppm by mass. [0037 1<Ejemplo de Comparación 1> The crude phosphine obtained in Implementation Example 1 was defined as Comparison Example 1. Table 1 shows the amounts of water, P4, and diphosphine contained in the crude phosphine obtained.

[0038] <Ejemplo de comparación 2> Using a method identical to that of Example Embodiment 1, except passing the crude phosphine obtained by a method identical to that of Example Embodiment 1, through the IF-2020-17934125-APN-ANP#INPI Page 16 of 23. Activated carbon and type A silica gel, with a flow rate of 10 L / min, yielded retinned phosphine. Table 1 shows the amounts of water, Pt, and diphosphine contained in the retined phosphine obtained. In addition, the refined phosphine contained impurities other than water, Pt, and diphosphine, including H2 at 3,200 ppm by mass, N2 at 62.2 ppm by mass, O2 at 2 ppm by mass, AsHs at 200 ppm by mass, and CO2 at 0.2 ppm by mass.

[0039] <Ejemplo de comparación 4> Using a standard method, 300 g of aluminum phosphide were reacted according to the usual procedure by gradually adding 1 L of water heated to 40°C, thus producing 30 L of gas. This gas was introduced into a pressure vessel, which was cooled by immersion in liquid nitrogen at -200°C to condense the phosphine, thereby removing some of the water. The pressure vessel was then removed from the liquid nitrogen to obtain crude phosphine by gradually raising the temperature to room temperature. The crude phosphine obtained was refined using the same method as in Example 1, thus yielding refined phosphine. Table 1 shows the amounts of water, P4, and diphosphine contained in the refined phosphine obtained. In addition, the refined phosphine obtained contained impurities other than water, P4, and diphosphine, as well as H2 at 3.10 ppm by mass, 42.2 ppm by mass, O2 at 1 ppm by mass, AsH3 at 100 ppm by mass, and CO2 at 0.1 ppm by mass. IF-2020-17934125-APN-ANP#INPI Page 17 of 23 [0040 ]<Ejemplo de comparación 3> The crude phosphine obtained in the Example embodiment 4 was defined as Example comparison 3. Table 1 shows the amounts of water, L and diphosphine contained in the crude phosphine obtained. [00411 [Table 1] Phosphine (% by mass) Water* (ppm by mass) Pfl** (ppm by mass) Diphosphine*** (ppm by mass) Implementation Example 1 99.7 Not detected Not detected 20 Implementation Example 2 99.7 Not detected Not detected 22 Implementation Example 3 99h4 3 1 28 Comparison Example 1 98.5 500 1,000 10,000 Comparison Example 2 99.0 20 30 300 Implementation Example 4 99.6 Not detected Not detected Not detected Comparison Example 3 97.3 800 770 Not detected 1Detection limit: 1 ppm by mass ” Detection limit; 1 ppm by mass * Detection limit; 10 ppm by mass

[0042] Method for measuring the amount of water contained in phosphine gas: The measurement was performed using the Karl Fischer method with the Mctrohm AG 875KF gas moisture meter. The measurement temperature was set to 25°C. [0043[ Method for measuring the amount of phosphine content in gas: IF-2020-17934125-APN-ANP#INPI Page 18 of 23 The measurement was performed using the coloriué' ''ice method with phosphovanadomolybdate to a solution obtained by absorbing Pi as phosphine gas passed through cooled benzene and removing the phosphine by degassing. The measurement temperature was set to 25°C, [ 0044 ] Method for measuring the amount of diphosphine: The measurement was performed by applying the nuclear magnetic resonance (NMR) equipment {JNM-ECA500, of JECJL, Ltd.} to an acetone / dry ice solution where the phosphine gas was absorbed.

[0045] Method for measuring AsH3 contained in phosphine gas: A VARIAN-AAΞ4 0 (from Agilent Technologies, Inc.) was used as the atomic absorption spectrometry equipment. For the calibration curve, the standard solution for arsenic / atomic absorption spectrometry (1,000 ppm, from Wako Pure Chemical Industries, Ltd.) was used. As the sample, 100 mL of phosphine gas was integrally absorbed by 50 mL of 1 N aqueous potassium permanganate solution, and this absorption solution was analyzed for the amount of arsenic using atomic absorption spectrometry / absolute calibration method. From the measured amount of arsenic, the number of moles was calculated as Asllj, and the mass concentration of the conversion to arsine in the phosphine was calculated.

[0046] Method for measuring the purity of phosphine, and of H2, Na, O2, CO2: IF-2020-17934125-APN-ANP#INPI Page 19 of 23 The measurement was performed using gas chromatograph analysis (GC-7A, Shimadzu Corporation) under the conditions described below. The purity of phosphine was determined by subtracting the respective amounts of water, diphosphine, and AsH1n from the phosphine, and the analytical values ​​of the non-phosphine gas components detected by the gas chromatograph. Incidentally, in the Implementation Example and the Comparison Example, H2, N2, O2, and Cd1 were detected as non-phosphine gases. L 004 V1 Gas chromatograph measurement conditions; The measurement sample was subdivided under an inert gas environment into septum-stoppered containers, 0.2 pL of measurement sample was injected into the gas chromatograph (GC-7A, Shimadzu Corporation) using a syringe, and the measurement was performed under the following conditions; -Column: Pcrapak T 50 / 80 mesh (from GL Sciences Inc.) -Column temperature: 60°C -Detector: TCD, carrier gas: he (100 kPa pressure) The amount of impurity gas components was obtained using the area normalization method, according to which the peak ratio is calculated with respect to 100¾ of the total detected peak area.

[0048] [Evaluation] (1) Foreign body deposition: The phosphine gases obtained in the Implementation Examples and Comparison Examples were converted into IF-2020-17934125-APN-ANP#INPI Page 20 of 23 Liquefied phosphine was liquefied by applying pressure and filled into a 47 L high-pressure gas cylinder. The gas was then passed from this cylinder through a bright annealed stainless steel tube (SUS3Q4 TP-SC-B1 JI£ G3459) with an internal diameter of 3.18 mm and a length of 2 m, at a rate of 20 L / in. After 9 hours, the presence of powder deposition inside the tube was visually inspected, and an evaluation was performed according to the criteria mentioned below. The results are shown in Table 2. No dust was detected inside the tube. + : A powder was deposited inside the tube, and the formation of scale on the inner wall of the tube was detected.

[0049] [Table 2] Appearance or non-appearance of an attached object. Realization example 1 - Realization example 2 - Realization example 3 - Comparison example J + Comparison example 2 + Realization example 4 - Comparison example 3 +

[0050] {2) Spontaneous flammability The spontaneous ignition temperature was measured in accordance with IEC 60079-20-1:2010. As per the standard, the spontaneous ignition temperature measurement was performed by verifying whether or not spontaneous ignition occurred when the gas sample was injected into a 200 ml Erlenmeyer flask. IF-2020-17934125-APN-ANP#INPI Page 21 of 23. The Erlenmeyer flask was in an open state, heated to a predetermined temperature, and filled with air. A 20 ml gas sample (phosphine) was injected into the flask at a rate of 25 ml per second using a 200 ml airtight syringe. It was assumed that the gas would be spontaneously flammable if ignition occurred within 5 minutes of the end of the injection. The spontaneous ignition temperature was measured in 1°C increments starting at 20°C. As the flask and oven for heating the flask used in the test, those indicated in Figure Al do TEC60079-2 0-1: 2 0 0 011 were used. For the material of the flask, borosilicate glass was used. The equipment used to inject the gas sample was that indicated in Figure A.9 of IECÜ0079-20-1:2000. The result is shown in Table 3. |0051] |Table 3] II. Spontaneous Inflammation Temperature Example 1: No inflammation occurred even though the temperature was above 10°C. Example 2: No inflammation occurred even though the temperature was above 100°C. Example 3: No inflammation occurred even though the temperature was above 100°C. Comparison Example 1: 3°C. Comparison Example 2: 30°C. Example 4: No inflammation occurred even though the temperature was above 10°C. Comparison Example 3: 30°C. IF-2020-17934125-APN-ANP#INPI Page 22 of 23 [Industrial applicability] [0052 j The phosphine for fumigation of the present invention is a phosphine that exhibits effective control of clogging caused by impurities in the piping and valves of the fumigation gas supply equipment, and low spontaneous flammability. Furthermore, the fumigation method of the present invention is a safe method that prevents clogging of the fumigation gas supply equipment piping and reduces the possibility of spontaneous combustion. IF-2020-17934125-APN-ANP#INPI Page 23 of 23 Argentine Republic - National Executive Branch 2020 - Year of General Manuel Belgrano Additional Signature Sheet Graphic Report Number: IF-2020-17934125-APN-ANP#INPI CITY OF BUENOS AIRES Wednesday, March 18, 2020 Reference: 20190103839 The document was imported by the GEDO system with a total of 23 page(s). Digitally signed by GESTION DOCUMENTAL ELECTRONICA- GDE Date: 2020.03.18 21:15:47-03:00 Gaston Hernan Lopez Administrative Assistant National Patent Administration National Institute of Industrial Property Digitally signed by DOCUMENTAL MANAGEMENT ELECTRONICS-GDE Date: 2020.03.18 21:15:08 -03:00

Claims

1. A phosphine mixture composition for fumigation, characterized in that it has a P4 content of 10 ppm by mass or less and a water content of 10 ppm or less, and further has a diphosphine content of 100 ppm by mass or less, wherein when the phosphine has a concentration of more than 1% by volume in air at 54°C or less, the phosphine does not spontaneously ignite. Seven claims follow.