Method for stabilizing diethylhydroxylamine

Abstract

To provide a method for stabilizing diethylhydroxylamine that can improve the stability of diethylhydroxylamine, and to provide a diethylhydroxylamine-containing composition that exhibits excellent stability of diethylhydroxylamine. [Solution] The present invention provides a method for stabilizing diethylhydroxylamine, characterized by including isopropylhydroxylamine in a composition containing diethylhydroxylamine. When the amount of diethylhydroxylamine is X1 [parts by mass] and the amount of isopropylhydroxylamine is X2 [parts by mass], it is preferable to include the isopropylhydroxylamine such that the relationship 0.02 ≤ X2 / X1 ≤ 7.0 is satisfied.

Description

Technical Field

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[0001] The present invention relates to a method for stabilizing diethylhydroxylamine. In the law It relates to.

Background Art

[0002] Diethylhydroxylamine (DEHA) acts as a reducing agent and is used as a polymerization terminator, stabilizer, metal cleaner, and photographic developer (for example, Patent Document 1).

[0003] However, hydroxylamine, which is a water-soluble reducing agent, is unstable in the form of a free base in an aqueous solution and thus decomposes in a short period of time, resulting in discoloration and a decrease in effects.

[0004] As a method for stabilizing hydroxylamine, a method of adding cyclohexanediaminetetraacetic acid, thiamine hydrochloride, and a mixture of thiamine hydrochloride and cyclohexanediaminetetraacetic acid is known (for example, Patent Document 2).

[0005] However, with the conventional methods, diethylhydroxylamine cannot be sufficiently stabilized, and there is room for improvement.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] An object of the present invention is to provide a method for stabilizing diethylhydroxylamine that can improve the stability of diethylhydroxylamine. toni There is. [Means for solving the problem]

[0008] The purpose of this is as follows (1) ~ ( 2 This is achieved by the present invention as described in ). (1) A method for stabilizing diethylhydroxylamine, characterized by including isopropylhydroxylamine in a composition containing diethylhydroxylamine.

[0009] (2) The method for stabilizing diethylhydroxylamine according to (1) above, wherein the amount of diethylhydroxylamine is X1 [parts by mass] and the amount of isopropylhydroxylamine is X2 [parts by mass], and the isopropylhydroxylamine is contained such that the relationship 0.02 ≤ X2 / X1 ≤ 7.0 is satisfied. [Effects of the Invention]

[0013] The present invention provides a method for stabilizing diethylhydroxylamine that can improve the stability of diethylhydroxylamine. Toga can. [Brief explanation of the drawing]

[0014] [Figure 1] This figure shows the relationship between the IPHA content, the remaining DEHA percentage, and the remaining IPHA percentage after 52 days for the diethylhydroxylamine-containing compositions of Examples 1-5 and Comparative Example 1. [Figure 2] This figure shows the relationship between the blending ratio of DEHA and IPHA and the remaining DEHA rate after 13 days, 27 days, and 51 days for the diethylhydroxylamine-containing compositions of Examples 6-12 and Comparative Examples 2 and 3. [Figure 3] This figure shows the relationship between the blending ratio of DEHA and IPHA and the remaining IPHA rate after 13 days, 27 days, and 51 days for the diethylhydroxylamine-containing compositions of Examples 6-12 and Comparative Examples 2 and 3. [Figure 4]It is a diagram showing the relationship between the blending ratios of DEHA and IPHA and the total residual ratio of reducing agents after 13 days, 27 days, and 51 days for the diethylhydroxylamine-containing compositions of Examples 6 to 12 and Comparative Examples 2 and 3.

Embodiments for Carrying Out the Invention

[0015] Hereinafter, preferred embodiments of the present invention will be described in detail. [1] Method for Stabilizing Diethylhydroxylamine First, the method for stabilizing diethylhydroxylamine of the present invention will be described.

[0016] The method for stabilizing diethylhydroxylamine of the present invention is characterized by containing isopropylhydroxylamine in a composition containing diethylhydroxylamine.

[0017] As a result, isopropylhydroxylamine coexists in the composition containing diethylhydroxylamine (the diethylhydroxylamine-containing composition of the present invention described later is obtained), the stability of diethylhydroxylamine is improved, and in particular, the decomposition of the free base in the solubilized state can be suppressed, making it difficult to cause discoloration and reduction in effects.

[0018] More specifically, by effectively suppressing the decomposition of the free base of diethylhydroxylamine, problems such as a decrease in the effects related to the uses of diethylhydroxylamine (for example, polymerization terminators, stabilizers, metal cleaners, photographic developers, etc.) can be solved.

[0019] [1-1] Diethylhydroxylamine The diethylhydroxylamine used in the present invention will be described below.

[0020] Diethylhydroxylamine (DEHA) is represented by the following formula (1), acts as a reducing agent, and is used, for example, in polymerization terminators, stabilizers, metal cleaners, photographic developers, etc.

[0021] Diethylhydroxylamine is generally unstable in the free base state in a solubilized state or the like, decomposes in a relatively short period of time, and has problems such as discoloration and reduced effectiveness.

[0022] [Chemical formula]

[0023] In the present invention, at least a part of diethylhydroxylamine may exist in the form of a salt. Examples of salts of diethylhydroxylamine include sulfates, hydrochlorides, and the like.

[0024] [1-2] Isopropylhydroxylamine The isopropylhydroxylamine used in the present invention will be described below.

[0025] Isopropylhydroxylamine (IPHA) is represented by the following formula (2), acts as a reducing agent, and is used in a wide range of applications in various industries such as pharmaceuticals, agricultural chemicals, and organic synthesis.

[0026] [Chemical formula] <​​​​​​​​In the diethylhydroxylamine stabilization method of the present invention, when the amount of diethylhydroxylamine is X1 [parts by mass] and the amount of isopropylhydroxylamine is X2 [parts by mass], it is preferable to include isopropylhydroxylamine such that the relationship 0.02 ≤ X2 / X1 ≤ 7.0 is satisfied, more preferably isopropylhydroxylamine such that the relationship 0.10 ≤ X2 / X1 ≤ 4.0 is satisfied, and even more preferably isopropylhydroxylamine such that the relationship 0.20 ≤ X2 / X1 ≤ 1.0 is satisfied.

[0029] This allows for maintaining both the stability and effectiveness of diethylhydroxylamine at a higher level.

[0030] [1-3] Mixture of diethylhydroxylamine and isopropylhydroxylamine As described above, the method for stabilizing diethylhydroxylamine according to the present invention is characterized by including isopropylhydroxylamine in a composition containing diethylhydroxylamine. That is, the method for stabilizing diethylhydroxylamine according to the present invention includes a step of mixing diethylhydroxylamine and isopropylhydroxylamine (diethylhydroxylamine-isopropylhydroxylamine mixing step). By going through such a step, the diethylhydroxylamine-containing composition of the present invention, which will be described later, is obtained.

[0031] In this step (the diethylhydroxylamine-isopropylhydroxylamine mixing step), for example, only diethylhydroxylamine and isopropylhydroxylamine may be mixed, or other components (components different from diethylhydroxylamine and isopropylhydroxylamine) may be mixed in addition to these.

[0032] Examples of such components include those described in sections [2-3] to [2-5] below.

[0033] In the diethylhydroxylamine-isopropylhydroxylamine mixing step, the components of the target diethylhydroxylamine-containing composition may be mixed all at once or in multiple steps.

[0034] More specifically, in the diethylhydroxylamine-isopropylhydroxylamine mixing step, for example, isopropylhydroxylamine may be mixed with a composition containing diethylhydroxylamine and components other than diethylhydroxylamine, or diethylhydroxylamine may be mixed with a composition containing isopropylhydroxylamine and components other than isopropylhydroxylamine, or a composition containing diethylhydroxylamine and components other than diethylhydroxylamine may be mixed with a composition containing isopropylhydroxylamine and components other than isopropylhydroxylamine. In other words, for example, diethylhydroxylamine may be pre-mixed with components other than diethylhydroxylamine before mixing with isopropylhydroxylamine, and isopropylhydroxylamine may be pre-mixed with components other than isopropylhydroxylamine before mixing with diethylhydroxylamine.

[0035] [1-4] Others Furthermore, the diethylhydroxylamine stabilization method of the present invention may include other steps in addition to the diethylhydroxylamine-isopropylhydroxylamine mixing step. Examples of such steps include various pretreatment steps, intermediate treatment steps, and posttreatment steps.

[0036] More specifically, examples include a step of mixing a component different from both diethylhydroxylamine and isopropylhydroxylamine after the diethylhydroxylamine-isopropylhydroxylamine mixing step, a step of removing some of the components of a composition (for example, insoluble matter or at least some of the liquid medium) from a composition containing diethylhydroxylamine and isopropylhydroxylamine obtained in the process of implementing the diethylhydroxylamine stabilization method of the present invention, and a step of preparing multiple compositions containing diethylhydroxylamine and isopropylhydroxylamine and mixing them.

[0037] [2] Diethylhydroxylamine-containing composition Next, the diethylhydroxylamine-containing composition of the present invention will be described.

[0038] The diethylhydroxylamine-containing composition of the present invention contains diethylhydroxylamine and isopropylhydroxylamine.

[0039] This configuration makes it possible to provide a diethylhydroxylamine-containing composition with excellent stability of diethylhydroxylamine. In particular, it is possible to provide a diethylhydroxylamine-containing composition that is less prone to discoloration and loss of effectiveness by suppressing the decomposition of free bases in the dissolved state.

[0040] [2-1] Diethylhydroxylamine The diethylhydroxylamine-containing composition of the present invention contains diethylhydroxylamine.

[0041] The content of diethylhydroxylamine in the diethylhydroxylamine-containing composition (or, in the case of a salt of diethylhydroxylamine, the content when converted to diethylhydroxylamine having the chemical structure shown in formula (1) above) is not particularly limited, but for example, if the diethylhydroxylamine-containing composition is a liquid composition containing an aqueous medium as described later, it is preferably 0.1% by mass or more and 20.0% by mass or less, more preferably 0.4% by mass or more and 15.0% by mass or less, and even more preferably 0.5% by mass or more and 6.0% by mass or less.

[0042] Furthermore, for example, if the diethylhydroxylamine-containing composition is a solid composition, the content of diethylhydroxylamine in the diethylhydroxylamine-containing composition (or, if a salt of diethylhydroxylamine is included, the content when converted to diethylhydroxylamine having the chemical structure shown in formula (1) above) is preferably 6.5% by mass or more and 98.0% by mass or less, more preferably 10.0% by mass or more and 90.1% by mass or less, and even more preferably 30.0% by mass or more and 83.3% by mass or less.

[0043] This improves the stability of the diethylhydroxylamine-containing composition while allowing the inherent functions of diethylhydroxylamine to be exhibited more effectively. Furthermore, even when the diethylhydroxylamine-containing composition is diluted to a relatively high dilution ratio, the inherent functions of diethylhydroxylamine can be fully exhibited.

[0044] [2-2] Isopropylhydroxylamine

[0045] The content of isopropylhydroxylamine in the diethylhydroxylamine-containing composition (or, if it contains a salt of isopropylhydroxylamine, the total content when converted to isopropylhydroxylamine having the chemical structure shown in formula (2) above) is not particularly limited, but for example, if the diethylhydroxylamine-containing composition is a liquid composition containing an aqueous medium as described later, it is preferably 0.002% by mass or more and 20.0% by mass or less, more preferably 0.04% by mass or more and 6.0% by mass or less, and even more preferably 0.1% by mass or more and 3.5% by mass or less.

[0046] Furthermore, for example, if the diethylhydroxylamine-containing composition is a solid composition, the content of isopropylhydroxylamine in the diethylhydroxylamine-containing composition (or, if it contains a salt of isopropylhydroxylamine, the total content when converted to isopropylhydroxylamine having the chemical structure shown in formula (2) above) is preferably 0.1% by mass or more and 87.5% by mass or less, more preferably 7.6% by mass or more and 80.0% by mass or less, and even more preferably 15.7% by mass or more and 50.0% by mass or less.

[0047] This makes it possible to improve the stability of the diethylhydroxylamine-containing composition. In particular, the above effects can be obtained while suppressing a relatively low content of diethylhydroxylamine in the diethylhydroxylamine-containing composition, thereby more reliably improving the stability of the diethylhydroxylamine contained in the diethylhydroxylamine-containing composition.

[0048] When the content of diethylhydroxylamine in the diethylhydroxylamine-containing composition is X3 [mass%] and the content of isopropylhydroxylamine in the diethylhydroxylamine-containing composition is X4 [mass%], it is preferable that the relationship 0.02 ≤ X4 / X3 ≤ 7.0 is satisfied, more preferably that the relationship 0.10 ≤ X4 / X3 ≤ 4.0 is satisfied, and even more preferably that the relationship 0.20 ≤ X4 / X3 ≤ 1.0 is satisfied.

[0049] This allows for maintaining both the stability and effectiveness of diethylhydroxylamine at a higher level.

[0050] [2-3] Liquid media The diethylhydroxylamine-containing composition of the present invention may contain diethylhydroxylamine and isopropylhydroxylamine as described above, but may also contain a liquid medium having the function of dissolving or dispersing them.

[0051] This allows, for example, a diethylhydroxylamine-containing composition to be made into a suitable liquid composition, improving the ease of handling of the diethylhydroxylamine-containing composition. Furthermore, conventionally, when a composition containing diethylhydroxylamine is a liquid composition containing a liquid medium that has the function of dissolving or dispersing diethylhydroxylamine, the stability of the composition tends to decrease particularly easily. However, according to the present invention, even in a composition containing a liquid medium, the stability of diethylhydroxylamine can be made sufficiently excellent. In other words, the effects of the present invention are more pronounced when the diethylhydroxylamine-containing composition contains a liquid medium.

[0052] The liquid medium is not particularly limited as long as it is a liquid component that functions as a solvent or dispersion medium for dissolving or dispersing diethylhydroxylamine and isopropylhydroxylamine as solute or disperse phase, but examples of liquid mediums include water; ketone compounds such as methyl ethyl ketone (MEK), acetone, diethyl ketone, methyl isobutyl ketone (MIBK), methyl isopropyl ketone (MIPK), cyclohexanone, 3-heptanone, and 4-heptanone; methanol, ethanol, n-propanol, isopropanol, n-butanol, Alcohol compounds such as i-butanol, t-butanol, 3-methyl-1-butanol, 1-pentanol, 2-pentanol, n-hexanol, cyclohexanol, 1-heptanol, 1-octanol, 2-octanol, 2-methoxyethanol, allyl alcohol, furfuryl alcohol, phenol and other monohydric alcohols, ethylene glycol, propylene glycol, butylene glycol, glycerin and other polyhydric alcohols; diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, 1,2-dimethyl Ether compounds such as xyethane (DME), 1,4-dioxane, tetrahydrofuran (THF), tetrahydropyran (THP), anisole, diethylene glycol dimethyl ether (diglym), 2-methoxyethanol, condensates of the aforementioned polyhydric alcohols (polyhydric alcohol ethers), and alkyl ethers of the aforementioned polyhydric alcohols or polyhydric alcohol ethers (e.g., methyl ether, ethyl ether, butyl ether, hexyl ether, etc.); cellosolve compounds such as methyl cellosolve, ethyl cellosolve, and phenyl cellosolve; Aliphatic hydrocarbon compounds such as hexane, pentane, heptane, cyclohexane, methylcyclohexane, octane, didecane, methylcyclohexene, and isoprene; aromatic hydrocarbon compounds such as toluene, xylene, benzene, ethylbenzene, and naphthalene; aromatic heterocyclic compounds such as pyridine, pyrazine, furan, pyrrole, thiophene, 2-methylpyridine, 3-methylpyridine, 4-methylpyridine, and furfuryl alcohol; amide compounds such as N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMA);Examples include halogen compounds such as dichloromethane, chloroform, 1,2-dichloroethane, trichloroethylene, and chlorobenzene; ester compounds such as acetylacetone, ethyl acetate, methyl acetate, isopropyl acetate, isobutyl acetate, isopentyl acetate, ethyl chloroacetate, butyl chloroacetate, isobutyl chloroacetate, ethyl formate, isobutyl formate, ethyl acrylate, methyl methacrylate, and ethyl benzoate; amine compounds such as trimethylamine, hexylamine, triethylamine, and aniline; nitrile compounds such as acrylonitrile and acetonitrile; nitro compounds such as nitromethane and nitroethane; and aldehyde compounds such as acetaldehyde, propionaldehyde, butyraldehyde, pentanal, and acrylaldehyde. One or more of these can be selected and used in combination.

[0053] When a diethylhydroxylamine-containing composition contains a liquid medium, it is particularly preferable that the liquid medium contains a highly hydrophilic compound (for example, a compound that is miscible with water in any proportion), and more preferably contains water.

[0054] This allows diethylhydroxylamine and isopropylhydroxylamine to be contained in a more favorably dissolved state in the diethylhydroxylamine-containing composition, more effectively preventing unintended aggregation of diethylhydroxylamine and isopropylhydroxylamine (for example, when the diethylhydroxylamine-containing composition is a dispersion, the dispersed phases constituting the dispersion aggregate to form coarse aggregates, reducing dispersion stability or causing precipitates), and more effectively preventing unintended variations in the amount of diethylhydroxylamine and isopropylhydroxylamine added to liquids such as photographic developers.

[0055] Furthermore, water is advantageous because it is readily available and highly safe. In addition, diethylhydroxylamine generally has the problem that, in solution form, discoloration and a decrease in effectiveness due to the decomposition of free bases, as described above, progresses particularly rapidly. This tendency is more pronounced when water is used as the solvent. However, in the present invention, even when the diethylhydroxylamine-containing composition contains water, the occurrence of such problems can be effectively suppressed. In other words, the effects of the present invention are more pronounced when the diethylhydroxylamine-containing composition contains water.

[0056] When the liquid medium constituting the diethylhydroxylamine-containing composition contains water, the proportion of water to the total liquid medium contained in the diethylhydroxylamine-containing composition is preferably 50% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more. This allows the effects mentioned above to be more pronounced.

[0057] [2-4] pH adjusters The diethylhydroxylamine-containing composition of the present invention may further contain, for example, a pH adjusting agent.

[0058] Examples of pH adjusting agents include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate, lithium carbonate, sodium phosphate, potassium phosphate, ammonia, and amines.

[0059] If the diethylhydroxylamine-containing composition of the present invention contains a pH adjusting agent, the content of the pH adjusting agent in the diethylhydroxylamine-containing composition of the present invention is preferably 10.0% by mass or less.

[0060] [2-5] Other ingredients The diethylhydroxylamine-containing composition of the present invention may contain components other than those listed above. Hereinafter, in this section, such components will also be referred to as "other components."

[0061] Other components include, for example, thickeners such as sodium polyacrylate, corrosion inhibitors such as oxycarboxylic acids, reducing agents such as sodium sulfite, oxygen absorbers, chelating agents, antioxidants, excipients, gelling agents, colorants, fillers, binders, solubilizers, preservatives, wetting agents, surfactants, emulsifiers, dispersants, turbidifiers, solutions, suspensions, fragrances, scents, coating agents, and drying agents.

[0062] The content of other components in the diethylhydroxylamine-containing composition is preferably 6.0% by mass or less, and more preferably 5.0% by mass or less. The lower limit of the content of other components is 0% by mass.

[0063] [2-6] Other conditions When the diethylhydroxylamine-containing composition of the present invention is a liquid containing water, the pH of the diethylhydroxylamine-containing composition is preferably 10 or higher, more preferably 12 or higher, and even more preferably 14 or higher.

[0064] Conventionally, there has been a problem in that the stability of diethylhydroxylamine tends to decrease particularly in compositions with a particularly high pH. However, in the present invention, the stability of diethylhydroxylamine can be made sufficiently high even in compositions with a particularly high pH (compositions containing diethylhydroxylamine). In other words, the effects of the present invention are more pronounced when the above-mentioned pH conditions are met.

[0065] Unless otherwise specified, the pH values ​​shown in this specification are those at 25°C.

[0066] The form of the diethylhydroxylamine-containing composition of the present invention is not particularly limited, and examples include tablets, powders (including granules), liquids, gels, pastes, and the like.

[0067] [3] Forms of use of diethylhydroxylamine-containing compositions Next, the forms of use of the diethylhydroxylamine-containing composition of the present invention will be described.

[0068] The diethylhydroxylamine-containing composition of the present invention can be used, for example, as a polymerization inhibitor in the polymerization reaction of styrene-butadiene rubber, as a stabilizer for styrene monomers, as a metal cleaning agent for CMP cleaning, as a photographic developing agent, and the like.

[0069] Although preferred embodiments of the present invention have been described above, the present invention is not limited to these. [Examples]

[0070] The present invention will be described in more detail below with specific examples, but the present invention is not limited to the following examples. In the following description, processes for which temperature and humidity conditions are not specifically stated were performed at room temperature (25°C) and relative humidity of 50%. Similarly, for various measurement conditions, unless specifically stated, the values ​​are for room temperature (25°C) and relative humidity of 50%.

[0071] [4] Stability test of diethylhydroxylamine-containing composition First, diethylhydroxylamine-containing compositions were prepared by fixing the amount of diethylhydroxylamine (DEHA) and varying the amount of isopropylhydroxylamine (IPHA), and their stability was evaluated.

[0072] [4-1] Preparation of diethylhydroxylamine-containing composition (Example 1) A diethylhydroxylamine-containing composition was prepared by mixing the following raw materials. Diethylhydroxylamine (DEHA): 5.95% by mass Isopropylhydroxylamine (IPHA): 0.15% by mass NaOH: 8.0% by mass Sodium polyacrylate: 2.4% by mass Pure water: 83.5% by mass (remaining amount)

[0073] (Examples 2-5) A diethylhydroxylamine-containing composition was prepared in the same manner as in Example 1, except that the DEHA content was fixed at 5.95% by mass, and the IPHA and pure water content was as shown in Table 1.

[0074] (Comparative Example 1) A diethylhydroxylamine-containing composition was prepared in the same manner as in Example 1, except that IPHA was not included and the water content was as shown in Table 1.

[0075] Table 1 summarizes the proportions of each component used in the production of the diethylhydroxylamine-containing compositions of Examples 1-5 and Comparative Example 1. In the following table, diethylhydroxylamine is abbreviated as "DEHA" and isopropylhydroxylamine as "IPHA". The diethylhydroxylamine-containing compositions obtained in Examples 1-5 and Comparative Example 1 all had a pH of 14 or higher.

[0076] [Table 1]

[0077] [4-2] Rating The diethylhydroxylamine-containing compositions obtained in Examples 1-5 and Comparative Example 1 were stored for 52 days under the following conditions: storage temperature: room temperature (25°C), presence of light: dark, open environment. The above storage conditions were assumed to be those of storage in an opened container.

[0078] Then, after the initial (0 days), 5 days, 13 days, 31 days, and 52 days, the concentrations (residual concentrations) of diethylhydroxylamine (DEHA) and isopropylhydroxylamine (IPHA) were measured using high-performance liquid chromatography (HPLC) under the same measurement conditions as described above, and the residual percentage (%) relative to the initial concentration was calculated for each.

[0079] Table 2 shows the relationship between the number of days elapsed and the remaining DEHA rate for the diethylhydroxylamine-containing compositions obtained in Examples 1-5 and Comparative Example 1, and Table 3 shows the relationship between the number of days elapsed and the remaining IPHA rate. Figure 1 shows the relationship between the IPHA content, the remaining DEHA rate, and the remaining IPHA rate after 52 days for the diethylhydroxylamine-containing compositions of Examples 1-5 and Comparative Example 1.

[0080] [Table 2]

[0081] [Table 3]

[0082] Figure 1 shows that the overall retention rate was higher for DEHA than for IPHA. In all of the examples that included IPHA, the retention rate of DEHA was higher compared to Comparative Example 1, which did not include IPHA, indicating that an improvement in stability was achieved.

[0083] [5] Stability test of diethylhydroxylamine-containing composition Next, while keeping the total blending ratio of diethylhydroxylamine (DEHA) and isopropylhydroxylamine (IPHA) fixed, diethylhydroxylamine-containing compositions were prepared by changing their blending ratios, and their stability was evaluated.

[0084] [5-1] Preparation of diethylhydroxylamine-containing composition (Example 6) A diethylhydroxylamine-containing composition was prepared by mixing the following raw materials. Diethylhydroxylamine (DEHA): 3.5% by mass Isopropylhydroxylamine (IPHA): 0.5% by mass NaOH: 8.0% by mass Sodium polyacrylate: 2.4% by mass Pure water: 85.6% by mass (remaining amount)

[0085] (Examples 7-12) A diethylhydroxylamine-containing composition was prepared in the same manner as in Example 6, except that the blending ratios of DEHA and IPHA were set as shown in Table 4 so that the total blending ratio of DEHA and IPHA was 4% by mass.

[0086] (Comparative Example 2) A diethylhydroxylamine-containing composition was prepared in the same manner as in Example 6, except that isopropylhydroxylamine (IPHA) was not included.

[0087] (Comparative Example 3) A diethylhydroxylamine-containing composition was prepared in the same manner as in Example 6, except that diethylhydroxylamine (DEHA) was not included.

[0088] Table 4 summarizes the proportions of each component used in the production of the diethylhydroxylamine-containing compositions of Examples 6-12 and Comparative Examples 2 and 3.

[0089] [Table 4]

[0090] [5-2] Rating The diethylhydroxylamine-containing compositions obtained in Examples 6-12 and Comparative Examples 2 and 3 were stored for 51 days under the following conditions: storage temperature: room temperature (25°C), presence of light: dark, open environment. The above storage conditions were assumed to be those of storage in an opened container. Then, after the initial (0 days), 8 days, 13 days, 21 days, 27 days, 42 days, and 51 days, the concentrations (residual concentrations) of diethylhydroxylamine (DEHA) and isopropylhydroxylamine (IPHA) were measured using high-performance liquid chromatography (HPLC) under the same measurement conditions as described above, and the residual percentage (%) relative to the initial concentration was calculated for each.

[0091] Table 5 shows the relationship between the number of days elapsed and the remaining DEHA for the diethylhydroxylamine-containing compositions obtained in Examples 6-12 and Comparative Examples 2 and 3, and Table 6 shows the relationship between the number of days elapsed and the remaining IPHA for the diethylhydroxylamine-containing compositions of Examples 6-12 and Comparative Examples 2 and 3.

[0092] [Table 5]

[0093] [Table 6]

[0094] Figure 2 shows the relationship between the blending ratio of DEHA and IPHA and the remaining DEHA rate after 13, 27, and 51 days for the diethylhydroxylamine-containing compositions of Examples 6-12 and Comparative Examples 2 and 3, and Figure 3 shows the relationship between the blending ratio of DEHA and IPHA and the remaining IPHA rate after 13, 27, and 51 days for the diethylhydroxylamine-containing compositions of Examples 6-12 and Comparative Examples 2 and 3.

[0095] Furthermore, since both DEHA and IPHA are reducing agents, the total residual reducing agent rate was evaluated. Total reducing agent remaining rate (%) = [{DEHA initial blending ratio (mass%) x DEHA residual rate (%) + IPHA initial blending ratio (mass%) x IPHA residual ratio (%)} ÷ {DEHA initial blending ratio (mass%) + IPHA initial blending ratio (mass%)}] × 100 Table 7 shows the results of the total reducing agent residue rate for the diethylhydroxylamine-containing compositions of Examples 6-12 and Comparative Examples 2 and 3.

[0096] [Table 7]

[0097] Figure 4 shows the relationship between the blending ratio of DEHA and IPHA and the total reducing agent remaining rate after 13 days, 27 days, and 51 days for the diethylhydroxylamine-containing compositions of Examples 6-12 and Comparative Examples 2 and 3. The dashed line in the figure represents the estimated survival rate when DEHA and IPHA have an additive effect.

[0098] Figure 4 shows that adding IPHA to DEHA resulted in a stabilizing effect on DEHA. In particular, in Examples 6 to 12, where the ratio of IPHA to DEHA (DEHA / IPHA) was between 0.14 and 7.0, the total reducing agent residue rate was superior to the estimated residue rate shown by the dashed line (the residue rate estimated from the additive effect of DEHA and IPHA). In other words, in all cases, a superior stabilizing effect was obtained due to the synergistic effect of DEHA and IPHA.

[0099] As is clear from the above results, the diethylhydroxylamine-containing composition of the present invention showed suppressed decomposition of free bases even in a dissolved state. In other words, the diethylhydroxylamine-containing composition of the present invention exhibited excellent stability. In contrast, satisfactory results were not obtained in the comparative example.

Claims

1. A method for stabilizing diethylhydroxylamine, characterized by including isopropylhydroxylamine in a composition containing diethylhydroxylamine.

2. The amount of diethylhydroxylamine is X １ [Parts by mass], the amount of isopropylhydroxylamine is X ２ When [mass part], 0.02 ≤ X ２ / X １ The method for stabilizing diethylhydroxylamine according to claim 1, wherein the isopropylhydroxylamine is included in such a way that the relationship ≤ 7.0 is satisfied.

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