Title of Invention	A PROCESS FOR PRODUCTION OF 1,3-DIIODOHYDANTOIN COMPOUND
Abstract	The present invention provides a means which can inhibit release of I2 in production or storage of 1, 3-diiodohydantoin compound, and thereby solve decrease in purity of the compound and various problems caused by I2. The present invention provides a production method for 1,3-diiodohydantoin compound comprising a step to prepare a wet body containing a 1,3-diiodohydantoin compound, and (1) a step to dry the wet body by contacting the wet body with heated gas or (2) a step to lyophilize the wet body, a storage method for 1, 3-diiodohydantoin compound comprising a step to store a 1,3-diiodohydantoin compound under a temperature condition of 15 °C or lower, and a 1, 3-diiodohydantoin compound wherein content of released I2 is 1% by mass or less.

Title of Invention

A PROCESS FOR PRODUCTION OF 1,3-DIIODOHYDANTOIN COMPOUND

Abstract

The present invention provides a means which can inhibit release of I2 in production or storage of 1, 3-diiodohydantoin compound, and thereby solve decrease in purity of the compound and various problems caused by I2. The present invention provides a production method for 1,3-diiodohydantoin compound comprising a step to prepare a wet body containing a 1,3-diiodohydantoin compound, and (1) a step to dry the wet body by contacting the wet body with heated gas or (2) a step to lyophilize the wet body, a storage method for 1, 3-diiodohydantoin compound comprising a step to store a 1,3-diiodohydantoin compound under a temperature condition of 15 °C or lower, and a 1, 3-diiodohydantoin compound wherein content of released I2 is 1% by mass or less.

Full Text	1 DESCRIPTION 1,3-DIIODOHYDANTOIN COMPOUND AND PRODUCTION METHOD THEREOF Technical Field The present invention relates to 1,3-diiodohydantoin compound and production method thereof. More in detail, the present invention relates to improvement in long-term stability of the aforementioned compounds. Background Art 1, 3-Diiodohydantoin compound (hereinafter, also simply referred to as "DIH compound") has been widely used as a sensitive material for photography or the like, or an iodizing agent or an oxidizing agent in production processes for medical drugs, agricultural chemicals, chemicals, or the like. As a method for producing the DIH compounds, for example, a technique, in which a hydantoin compound is reacted with iodine monochloride in the presence of a base in an aqueous solution, has been disclosed (see, for example, JP-A-2002-30072 and J. Org. Chem., 30(1965), 1101-1104). Such technique has advantageous points that it is simple and highly efficient as well as easy post-treatments such as purification and waste liquid treatment. Here, in the specification of JP-A-2002-30072, a technique for purifying a DIH compound from reaction system has been described as "deposited crystal is collected by filtration, and the resultant crystal is dried under a reduced pressure". Meanwhile, the DIH compounds produced by the techniques or the like described in the above literatures are usually stored until the time to be used for the above applications. 2 As such a storage method, for example, a technique, in which the compound is stored under a reduced pressure and nitrogen atmosphere in a darkplace, hasbeen disclosed (see, forexample, J. Labelled Compd. Radiopharm., 44-12(2001), 815-830). Disclosure of the Invention However, there is no description about the DIH compounds superior in easy handling and good storage stability, it has been revealed from the study by the present inventors that there is a problem that the aforementioned DIH compound tends to decrease in purity when the DIH compound is produced by the production method described in the above literature or when the DIH compound is stored by a common method as described in the above literature . Such decrease in purity is considered to be caused by release of iodine atom as an elementary substance (I2) of iodine by decomposition of the iodine compound. The release of I2 could cause problems such as coloration or corrosion of material or equipment by aforementioned I2 and increased risk for operators. Thus, an object of the present invention is to provide a means to inhibit release of I2 in production or storage of DIH compound, and thereby solve decrease in purity of DIH compound or various problems caused by I2. In order to solve the above problems, the present inventors intensively searched for a cause of release of I2 in production or storage of DIH compound. As a result, the present inventors have found that DIH compound is unstable in a state of wet body, in which a certain level of liquid component such as water and an organic solvent is contained, even at an ordinary temperature, and that this instability causes the aforementioned release of I2. In addition, the release of I2 from such wet body becomes more 3 remarkable under a comparatively high temperature condition. Therefore, based on the above knowledge, the present inventors have found that the decomposition of DIH compound and the release of I2 accompanying thereto can be prevented by controlling drying means in production of DIH compound and temperature condition in storage thereof, and finally accomplished the present invention. That is, the present invention provides a production method for 1,3-diiodohydantoin compound comprising a step to provide a wet body containing a 1,3-diiodohydantoin compound, and (1) a step to dry the wet body by contacting the wet body with heated gas or (2) a step to lyophilize the wet body. In addition, the present invention provides a storage method for a 1, 3-diiodohydantoin compound comprising a step to store a 1,3-diiodohydantoin compound under a temperature condition of 15°C or lower. Further, the present invention provides a 1, 3-diiodohydantoin compound wherein content of released I2 is 1% by mass or less. According to the present invention, release of I2 during production or storage of DIH compound can be inhibited, and thereby decrease in purity of DIH compound or incidence of various problems caused by I2 can be prevented. Best Mode for Carrying Out the Invention A first aspect of the present invention relates to a production method for DIH compound. Specifically, firstly a wet body containing a DIH compound is provided. Subsequently, (1) the wet body is dried by contacting the wet body with a heated gas, or (2) the wet body is lyophilized. As described above, it has been found out that DIH compound 4 is unstable in a state of wet body, in which a certain level of liquid component is contained therein, and the instability causes the release of I2 as described above. In addition, it has been also found out that such release of I2 becomes remarkable under a comparatively higher temperature condition . In the present invention, a method to inhibit effectively this release of I2 is provided. Incidentally, although mechanism of the release of I2 in production or storage of DIH compound has not been necessarily clarified, a mechanism based on decomposition of the DIH compound has been presumed. However, suchmechanism is only a presumption, and even if the release of I2 occurs via another mechanism, the technical scope of the present invention is not affected at all. Hereinafter, the production method of the first aspect of the present invention will be explained in detail. Firstly, the first step in the production method of the first aspect of the present invention, that is, the step in which a wet body containing a DIH compound is provided will be described. In the present invention, "DIH compound" means a compound represented by the following chemical formula (I): [Formula 1] (wherein R1 and R2 are each independently a hydrogen atom or a Ci-C6 alkyl group). Way of procurement for the wet body containing a DIH compound is not particularly limited. The wet body containing 5 a DIH compound may be used by synthesizing according to the well known technique (e.g. the technique described in the aforementioned JP-A-2002-30072) or may be used by purchasing a commercially available product. As a technique to prepare the wet body containing a DIH compound by oneself, for example, the technique shown below can be used. However, the following preparation method is only an example, and it is needless to say that "wet body containing a DIH compound" prepared by a technique other than the following mode may be used. In the present invention, the DIH compound (Chemical Formula (I)) is prepared, for example, by reacting a hydantoin compound (Chemical Formula (II)) with iodine monochloride in the presence of a base in an aqueous solution, as shown in the following Chemical Reaction Scheme 1. [Formula 2] wherein R1 and R2 are as defined above. In order to prepare the DIH compound according to the Chemical Reaction Scheme 1, firstly a hydantoin compound represented by the Chemical Formula (II), which is used as a raw material, is provided. [Formula 3] 6 wherein R1 and Rz are as defined above. As described above, R1 and R2 is each a hydrogen atom or a Ci-C6 alkyl group. R1 and R2 may be same or different from each other. In view of yield in the synthesis reaction and easiness in handling, R1 and R2 are preferably identic-al- to each other. The alkyl group may be linear, branched or cyclic. Number of carbon atoms in the alkyl group is 1 to 6, preferably 1 to 2, and more preferably one. Specific example of the alkyl group includes methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, s-butyl group, t-butyl group, pentyl group, isopentyl group, neopentyl group, hexyl group, and the like. An alkyl group other than these may also be used. Among them, preferably both of R1 and R2 are methyl groups, from the viewpoints of industrially moderate price and easy availability. Way of procurement for the hydantoin compound (II) is not particularly limited. The hydantoin compound may be used by synthesizing according to the well known technique or may be used by purchasing a commercially available hydantoin compound. Iodine monochloride is a compound represented by the chemical formula of "IC1", and highly reactive due to containing iodine of (oxidation number + 1) , and used in various synthetic reactions as an iodizing agent. Way of procurement for iodine monochloride (IC1) is also not particularly limited. Iodine monochloride may be used by synthesizing according to the well known technique or may be used by purchasing commercially available iodine monochloride. Incidentally, as a technique to synthesize iodine monochloride by oneself, for example, a technique is exemplified, in which chlorine is passed over iodine, then liquefied and distilled. It is needless to say that iodine 7 monochloride synthesized by other technique may also be used. The reaction of a hydantoin compound and iodine monochloride is carried out in the presence of a base. This base acts as a catalyst in the reaction system containing a hydantoin compound and iodine monochloride. Specific mode of the base is not particularly limited, and a base which commonly used in such synthetic reaction can be similarly used. An example of the base includes, for example, hydroxides, carbonate salts and the like of alkali metals / alkaline earth metals such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium hydrogen carbonate, potassium carbonate, potassiumhydrogen carbonate, and the like. It should be noted that these bases may be used alone or in combination of two or more kinds. The above reaction is carried out in an aqueous solution, but a solvent other than water may be included therein. For example, amide type solvents and ester type solvents can be included. Compounding ratio of each component in the above reaction is not particularly limited, and conventionally known knowledge (in particular, aforementioned JP-A-2002-30072) can be referred to as appropriate. After completion of the above reaction, components other than DIH compound are removed from the reaction system. By this operation, a solution of DIH compound can be obtained. Subsequently, most of the solvent contained in the solution is removed. By this operation, a "wet body containing a DIH compound" can be prepared. However, the step in which solvent is removed, may be carried out before removing the components other than the DIH compound. The technique to remove the components other than DIH compound is not particularly limited, and, for example, a 8 technique such as filtration, recrystallization and extraction, and combination thereof can be exemplified. Other technique may also be used. In addition, the technique to remove most of the solvent from the- solution containing DIH compound.-is also not particularly limited, and, for example, a technique such as filtration, centrifugal separation and decantation, and combination thereof can be exemplified. Other technique may also be used. In this regard, the "wet body containing a DIH compound" to be provided in this step is composed of a DIH compound, a solvent, and in some case a small amount of impurity, but content of the solvent in the wet body is not particularly limited. As an example, content of solvent is around 8 to 30% by mass to total amount of the wet body. More solvent may be contained in the wet body, but too high content of the solvent could result in prolonged drying time leading to rise of production cost. Hereinafter, characteristic steps in the production method of the present invention will be explained. As described above, in the production method of the present invention, regarding the resultant "wet body containing a DIH compound", (1) the wet body is dried by contacting the wet body with a heated gas, or (2) the wet body is lyophilized. Firstly, the technique (1) is explained in detail. In the technique (1), the "wet body containing a DIH compound" prepared in the above is dried by contacting the wet body with a heated gas. Namely, in the technique (1), so called "fluidized drying" is employed. Conventionally, as a technique to dry the wet body containing a DIH compound, an industrially common drying 9 method had been employed. Specifically, drying method by heating under reduced pressure, e.g. using a conical dryer, drying method by heating under ordinary pressure, e.g. using a plate column dryer, and the like had been employed. However, the-present inventors have found out that a part of the wet . body containing a DIH compound decomposes and I2 is released by these methods. Specifically, when a wet body of a DIH compound (5,5-dimethyl body) containing 2 to 15% of water is heated at 40 °C for 3 hours, 4 to 6% of the compound is decomposed to release I2 . Also, when the wet body is similarly heatedat 70°C for 3 hours, 9 to 30% of the compound is decomposed. As a result, such problems as decrease in purity of DIH compound, and coloration or corrosion of material or equipment by released I2, and increased risk for operators could occur. On the contrary, according to the technique as described above, the release of I2, which had conventionally been a problem in drying a wet body, can be inhibited to the minimum. In this regard, although mechanism, by which a difference in levels of released I2 arises between the conventional drying technique and the drying technique of the present invention, has not been perfectly clarified, it is considered that the DIH compound which is instable to heat may decompose because the wet body is exposed at a high temperature condition over a long period of time in such unit of several hours in the conventional drying technique. Consequently, according to the production method of the present invention, not only the release of I2 in production of DIH compound can be inhibited to the minimum, but also heating time can be reduced and rapid production is enabled, and this can contribute to reduction in production cost. However, the technical scope of the present invention should be determined based on the description in the claims, and the technical scope is not 10 affected by the mechanism. Specif ic mode of the f luidized drying is not particularly limited, and conventionally well known knowledge in the synthesis field of chemical compounds can be referred to as appropriate. Hereinafter, preferable mode in the fluidized drying is exemplified. However, fluidized drying is not limited only to the following mode. In the present invention, "heated gas" means a gas having a temperature level at which a wet body containing a DIH compound can be dried by contacting with the wet body. The heated gas is preferably a gas which does not react with the DIH compound. Specific kind of the heated gas includes, for example, nitrogen gas, argon gas, helium gas, air gas, and mixed gas thereof, but kind of the heated gas is not limited to them. As the heated gas, air gas is preferably used. Temperature of the heated gas in contact with aforementioned wet body is not particularly limited, and can be decided taking physical properties of the DIH compound to be prepared and general knowledge in fluidized drying into consideration comprehensively. However, temperature of the heated gas is preferably 20 to 200°C, more preferably 40 to 170°C, and furthers more preferably 90 to 130°C. Too low temperature of the heated gas requires prolonged drying time as a result of insufficient amount of heat, or could fail to dry up to a desired liquid content. On the contrary, too high temperature of the heated gas could give rise to deterioration (decomposition andmelting) of the DIH compound due to overheating. Flow rate of the heated gas in contact with aforementioned wet body is also not particularly limited, but preferably O.ltolO.O m/sec, more preferably 0.3to5.0 m/sec, and further more preferably 0.5 to 3.0 m/sec. Too low flow rate of the 11 heated gas requires prolonged drying time as a result of insufficient contact of the heated gas with the whole wet body, or could fail to dry up to a desired liquid content. On the contrary, too high flow rate of the heated gas could make collection of the-wet body difficult because of-excessive . scattering of the wet body. Next, the technique (2) is explained in detail. In the technique (2), the "wet body containing a DIH compound" provided as described above is lyophilized. By such technique, the release of ±2, which had conventionally been a problem in drying of the wet body, can also be inhibited to the minimum. In this regard, mechanism by which the conventional problem is solved by employing lyophilization is presumed to be similar to the case of the aforementioned fluidized drying. Thus, the techniques (1) and (2) are the same in the point to inhibit the release of I2 in drying the wet body to the minimum. "Lyophilization" is also referred to as lyophilize, and a technique in which a wet body is dried by freezing quickly the wet body at a temperature of the freezing point or below, and removing a solvent of the frozen body by sublimation by reducing pressure to a level of the vapor pressure of the solvent or below. Specific mode of the lyophilization is not particularly limited, and conventionally well known knowledge in the synthesis field of chemical compounds can be referred to as appropriate. Hereinafter, a preferable mode in the lyophilization is exemplified. However, the lyophilization is not limited to the following mode. Firstly, a wet body containing a DIH compound is cooled down quickly to a prescribed temperature. By this operation, 12 the aforementioned wet body is frozen. Temperature to be attained by the quick cooling is not particularly limited, but the wet body may be cooled down to preferably -196 to 0°C, and more preferably -100 to -20°C. After that, the frozen body is placed in a reducedpressure . In this case, pressure condition is not particularly limited, and pressure may be reduced to a level which is necessary to remove a solvent contained in the wet body. As an example, pressure may be reduced to around 10tol,500Pa, and preferably 100 to 700 Pa. When the wet body is driedby the technique (2) , preferably a solvent is further added to the "wet body containing a DIH compound" provided as described above to prepare a wet body in a slurry state, then the resultant wet body in a slurry state is lyophilized by the technique described above. According to this mode, such desirable effect that sublimation from inside is facilitated by freezing of whole wet body in a slurry state compared with the case when the wet body provided as described above is simply lyophilized as it is, can be obtained. In such mode, the solvent to be added to the wet body when the wet body in a slurry state is prepared is not particularly limited. However, a solvent, which does not react with the DIH compound and is easy to sublime in the following lyophilization, is preferably used. An example of the solvent to be added includes, besides water, ethyl acetate, n-butyl acetate, N, N-dimethylformamide, and the like. Among them, preferably water is further added from the viewpoints of moderate price, easy-handling, and being suitable for lyophilization. Addition amount of the solvent when the solvent is added to the wet body is also not particularly limited, but the 13 solvent may be added so that total content of the solvent to the whole amount of the wet body in a slurry state becomes preferably 30 to 70% by mass, and more preferably 50 to 60% by mass. According to the production method of the first aspect of the present invention, by any technique of (1) and (2), the release of I2 in production of DIH compound can be inhibited to the minimum, and conventional various problems associated with the release of I2 can be solved. In other words, according to the production method of the first aspect of the present invention, a DIH compound which has a more reduced content of released I2 than before can be produced. Namely, a second aspect of the present invention is a DIH compound which has a reduced content of free I2. In this case, content of the free I2 in the DIH compound of the second aspect of the present invention is preferably 1% by mass or less, more preferably 0.8% by mass or less, further more preferably .0.4% by mass or less, and particularly preferably 0.2% by mass or less. As described above, since the free I2 is an impurity to cause various problems, lower content of the free I2 in the resultant DIH compound is more preferable . However, the technical scope of the production method of the first aspect of the present invention is not necessarily limited only to a mode in which a DIH compound containing such amount of the free I2 is produced. In some case, a DIH compound containing the free I2 in an amount out of this range may be produced. In addition, the technical scope of the DIH compound of the present invention is not necessarily limited only to the mode in which the DIH compound is produced by the production method of the first aspect of the present invention, and in some case, the DIH compound may be produced by other production method. In this regard, as a content of free I2 in the DIH compound produced, a value 14 measured by the technique described in Example below should be employed. In addition, in the DIH compound of the second aspect of the present invention, besides the content of free I2, less content of water is also more preferable. This is because decomposition of DIH compound and release of I2 accompanying thereto in production and storage of DIH compound occur more easily when water content is higher. Specifically, content of water in the DIH compound of the second aspect of the present invention is preferably 6% by mass or less, more preferably 5% by mass or less, further more preferably 3% by mass or less, and particularly preferably 1% by mass . Consequently, when the wet body containing a DIH compound is subjected to fluidized drying (1) or lyophilization (2) in the production method of the first aspect of the present invention, drying conditions may be controlled so that content of water in the resultant DIH compound becomes a value in the above range. Application of the DIH compound of the second aspect of the present invention is not particularly limited, but it can be employed, for example, in applications such as a sensitive material of photography or an iodizing agent or an oxidizing agent in production processes for medical drugs, agricultural chemicals, chemicals, or the like. As described above, the production method for DIH compound was explained as the first aspect of the present invention, and the DIH compound itself was also explained as the second aspect of the present invention. The present invention also provides a storage method for DIH compound as a third aspect of the present invention. The storage method of the third aspect of the present invention has been made based on the knowledge that decomposition of DIH compound and release of I2 accompanying 15 thereto occurs more easily under a comparatively higher temperature condition. Namely, the third aspect of the present invention is a storage method comprising a step in which a DIH compound is stored under a temperature condition of-15°C or lower. The DIH compound to be used in the storage method of the third aspect of the present invention is not particularly limited, and conventionally well known DIH compound can be used. However, in view of sufficient inhibition of decomposition of DIH compound and release of I2 thereby, the DIH compound produced by the production method of the first aspect of the present invention or the DIH compound provided as the second aspect of the present invention is preferably used. Since specific mode of these DIH compounds is as described above, detailed explanation will be omitted here. In the third aspect of the present invention, the DIH compound is stored under a temperature condition of 15°C or lower, preferably 10°C or lower, and more preferably 5°C or lower. By this operation, the decomposition of DIH compound and the release of I2 thereby can be inhibited. In the third aspect of the present invention, specific mode other than the storage under the above temperature condition is not particularly limited, and conventionally well known knowledge about storage of chemical compounds can be referred to as appropriate . In this regard, in the present invention, concept of "storage" includes not only a mode when a DIH compound is placed in one position, but also a mode such as "transportation" in which a DIH compound is transferred among various places until it is used for a prescribed application. In the third aspect of the present invention, humidity condition in the storage of DIH compound is not particularly 16 limited, but generally it is preferable to be stored under a low humidity condition. Specifically, relative humidity (RH) in an atmosphere of storage place is preferably 50% or less, and more preferably 301 or less. In the storage method of the third aspect of-the present invention, DIH compound is usually stored in a packed state in a prescribed container. Specific mode of the container is also not particularly limited, and conventionally well known storage containers in storage field of chemical compounds can be employed as appropriate. Constituent material for the storage containers includes industrially commodity type of resins, and specifically includes polyethylene, polypropylene, polystyrene, polyester, polyvinyl chloride, polyvinylidene chloride, and the like. Shape of the storage containers is also not particularly limited, and shapes such as bag-like, box-like, drum-like, and the like are exemplified. Even by the storage method of the third aspect of the present invention, a very small amount of I2 can be released from DIH compound during storage. Consequently, the storage container is preferably those having a hermetically sealing function. From such viewpoint, as a constitutional material for the storage containers, polyvinylidene chloride / polyethylene composite material and high-barrier-performance polymers are preferably employed. Metal containers with resin lining can also be used as the storage containers . However, in such mode, it should be noted that the metal material could be corroded by penetration of a very small amount of free I2 when storage is continued for an extremely long period. In the storage method of the third aspect of the present invention, the temperature condition is not necessarily in 17 the above range through whole course of storage period, but the temperature condition may be in the above range in about 100% of the period except the period when the DIH compound is temporally stored under a temperature condition of around ordinary temperature because of transfer or the like. The storage method of the third aspect of the present invention may be combined with the production method of the first aspect of the present invention. For example, when a DIH compound is premised to be stored using the storage method of the third aspect of the present invention, it is convenient to produce the DIH compound according to the production method of the first aspect of the present invention, then to store directly the DIH compound by the storage method of the third aspect of the present invention. Examples Hereinafter, the present invention will be explained more in detail using Examples and Comparative Example, however, the technical scope of the present invention is not limited to the following modes. As a wet body containing a DIH compound, 5, 5-dimethyl-l, 3-diiodohydantoin (20 kg) containing n-butyl acetate (2% by mass) and water (13% by mass) was provided. The wet body provided as described above was charged into a fluidized dryer. The wet body was dried by contacting the wet body with air of 110°C as a heated gas in a flow rate of 1 m/sec for 30 minutes to obtain pale yellow crystalline powder of 5,5-dimethyl-l,3-diiodohydantoin in a purity of 98% or more. After that, contents of free I2 and water in the resultant 18 powder were determined. As a result, content of free I2 was 0.2% by mass or less, and content of water was 1% by mass or less. In this regard, the contents of free I2 and water were measured by the following techniques. Pleasuring method for contentOt "free I2> According to "First method: Method by heating drying under atmospheric pressure" in JIS-K0067"1992 4.1.4(1) described in "2004-edited JIS Handbook, 49, Chemical Analysis", a sample was heated at 60°C for 2 hours under the atmospheric pressure, and decrease in mass was measured to obtain a content of free I2. According to "First method: Method by heating drying under atmospheric pressure" in JIS-K0067"1992 4.1.4(1) described in "2004-edited JIS Handbook, 49, Chemical Analysis", the sample, which was used for measuring content of free I2, was dried at 105°C for 2 hours under the atmospheric pressure, and decrease in mass was measured to obtain a content of water. As a wet body containing a DIH compound, 5, 5-dimethyl-l, 3-diiodohydantoin (50 g) containing water (8% by mass) was provided. The wet body provided as described above was charged into a lyophilizer, then cooled down to -80°C to freeze the wet body. Subsequently, the resultant frozen body was dried by sublimation at 20°C for 22 hours under reduced pressure condition of 270 Pa to obtain pale yellow crystalline powder Of 5,5-dimethyl-l,3-diiodohydantoin in a purity of 95% or more. After that, contents of free I2 and water in the resultant powder were determined. As a result, content of free I2 was 19 0.2% by mass or less, and content of water was 5% by mass. As a wet body containing a DIH compound, 5,5-dimethyl-l,3-diiodohydantoin (21g) containing water (8% by mass) was provided. Water (22 g) as a solvent was further added to the wet body provided as described above to prepare a wet body in a slurry state. The wet body in a slurry state as described above was charged into a lyophilizer, and cooled down to -80°C to freeze the wet body. Subsequently, the resultant frozen body was dried by sublimation at20°Cforl4 hours under reduced pressure condition of 270 Pa to obtain pale yellow crystalline powder of 5, 5-dimethyl-l,3-diiodohydantoin in a purity of 98% or more. After that, contents of free I2 and water in the resultant powder were determined. As a result, content of free I2 was 0.2% by mass or less, and content of water was 1% by mass. The pale yellow crystalline powders of 5,5-dimethyl-l,3-diiodohydantoin obtained in Examples 1 to 3 described above were stored each in hermetically sealed state in a polyethylene-made container at 5°C. As a result, no change in appearance of the compound or content of released I2 was observed even after 6 months of time course. As a wet body containing a DIH compound, 5,5-dimethyl-l,3-diiodohydantoin (200 kg) containing n-butyl acetate (2%" by mass) and water (13% by mass) was provided. The wet body provided as described above was charged into a 1,000 L conical dryer, then, dried at 40 to 70°C under 20 a reduced pressure of 2,700 to 5,300 Pa. As a result, decomposition of 5,5-dimethyl-l,3-diiodohydantoin started to proceed after about 4 hours from the start of drying, and I2 was released. And after about 8 hours from the start of drying, vacuum line was blocked up by the released I2. From then on, drying by the conical dryer could not be continued. In this case, the resultant 5, 5-dimethyl-l, 3-diiodohydantoin was red crystal, and contained 2% by mass or more of released I2 and 8% by mass of water, and could not be used practically. In addition, this red crystal was stored in a hermetically sealed state in a polyethylene-made container at5°C. Releaseofl2further proceeded within several weeks, and such appearance that released I2 deposited in the upper part of the container was observed. As aDIHcompound, 5,5-dimethyl-l,3-diiodohydantoin (20 kg) (content of free I2: 0.2% by mass, content of water: 1% by mass) was provided. On the other hand, as storage containers, two bags made of polyvinylidene chloride / polyethylene composite material were provided. In each storage container provided as described above, the DIH compound (10 kg each) also provided as described above was packed, then each bag was heat-sealed after the packing. After that, one of the storage containers packed with the DIH compound was stored at 5°C (Example), and the other was stored at 25°C (Comparative Example). As a result, in the case of Example, no change in quality (specifically, content of released I2) of the DIH compound was observed even after one year or more of storage. On the contrary, in the case of Comparative Example, decomposition of the DIH compound 21 started to release I2 after 2 months of storage, and coloration of the bag was observed. From the results described above, it is indicated that decomposition of DIH compound and release of I2 thereby in drying can be inhibited and a high quality of DIH compound which is easy to handle and superior in storage stability can be produced by subjecting wet body containing a DIH compound to fluidized drying or lyophilization. In addition, according to the storage method of the present invention, it is indicated that the DIH compounds are kept in high quality over long term. Thus, according to the present invention, release of I2 in production or storage of DIH compound can be inhibited, and thereby prevent ion of decrease in purity of the DIH compound or occurrence of various problems caused by I2 can be expected. It should be noted that, the present invention is based on JP Application No. 2005-25557 filed on 2nd September, 2005, and the content of disclosure has been incorporated herein in its entirety by reference. 22 WHAT IS CLAIED IS: 1. A production method for 1,3-diiodohydantoin compound comprising: a step to provide a wet body comprising a 1,3-diiodohydantoin compound and a step to dry the wet body by contacting the wet body with heated gas. 2. A production method for 1,3-diiodohydantoin compound comprising a step to provide a wet body comprising a 1,3-diiodohydantoin compound and a step to lyophilize the wet body. 3. The production method according to claim 2, comprising further a step to prepare a wet body in a slurry state by adding a solvent to the provided wet body, wherein the wet body is the wet body in a slurry state. 4. The production method according to any one of claims 1 to 3, wherein the 1,3-diiodohydantoin compound is 5,5-dimethyl-l,3-diiodohydantoin. 5. A storage method for 1,3-diiodohydantoin compound comprising a step to store a 1,3-diiodohydantoin compound under a temperature condition of 15°C or lower. 6. The storage method according to claim 5, wherein the 1,3-diiodohydantoin compound is 5,5-dimethyl-l,3-diiodohydantoin. 7. A 1,3-diiodohydantoin compound, wherein content of released I2 is 1% by mass or less. 8. The 1, 3-diiodohydantoin compound according to claim 7, wherein further content of water is 6% by mass or less. 9. The compound according to claim 7 or 8, wherein the 1,3-diiodohydantoin compound is 5,5-dimethyl-l,3-diiodohydantoin. The present invention provides a means which can inhibit release of I2 in production or storage of 1, 3-diiodohydantoin compound, and thereby solve decrease in purity of the compound and various problems caused by I2. The present invention provides a production method for 1,3-diiodohydantoin compound comprising a step to prepare a wet body containing a 1,3-diiodohydantoin compound, and (1) a step to dry the wet body by contacting the wet body with heated gas or (2) a step to lyophilize the wet body, a storage method for 1, 3-diiodohydantoin compound comprising a step to store a 1,3-diiodohydantoin compound under a temperature condition of 15 °C or lower, and a 1, 3-diiodohydantoin compound wherein content of released I2 is 1% by mass or less.

Full Text

1
DESCRIPTION
1,3-DIIODOHYDANTOIN COMPOUND AND PRODUCTION METHOD THEREOF
Technical Field
The present invention relates to 1,3-diiodohydantoin
compound and production method thereof. More in detail, the
present invention relates to improvement in long-term
stability of the aforementioned compounds.
Background Art
1, 3-Diiodohydantoin compound (hereinafter, also simply
referred to as "DIH compound") has been widely used as a
sensitive material for photography or the like, or an iodizing
agent or an oxidizing agent in production processes for medical
drugs, agricultural chemicals, chemicals, or the like.
As a method for producing the DIH compounds, for example,
a technique, in which a hydantoin compound is reacted with
iodine monochloride in the presence of a base in an aqueous
solution, has been disclosed (see, for example,
JP-A-2002-30072 and J. Org. Chem., 30(1965), 1101-1104).
Such technique has advantageous points that it is simple and
highly efficient as well as easy post-treatments such as
purification and waste liquid treatment.
Here, in the specification of JP-A-2002-30072, a
technique for purifying a DIH compound from reaction system
has been described as "deposited crystal is collected by
filtration, and the resultant crystal is dried under a reduced
pressure".
Meanwhile, the DIH compounds produced by the techniques
or the like described in the above literatures are usually
stored until the time to be used for the above applications.

2
As such a storage method, for example, a technique, in which
the compound is stored under a reduced pressure and nitrogen
atmosphere in a darkplace, hasbeen disclosed (see, forexample,
J. Labelled Compd. Radiopharm., 44-12(2001), 815-830).
Disclosure of the Invention
However, there is no description about the DIH compounds
superior in easy handling and good storage stability, it has
been revealed from the study by the present inventors that
there is a problem that the aforementioned DIH compound tends
to decrease in purity when the DIH compound is produced by
the production method described in the above literature or
when the DIH compound is stored by a common method as described
in the above literature . Such decrease in purity is considered
to be caused by release of iodine atom as an elementary
substance (I2) of iodine by decomposition of the iodine
compound. The release of I2 could cause problems such as
coloration or corrosion of material or equipment by
aforementioned I2 and increased risk for operators.
Thus, an object of the present invention is to provide
a means to inhibit release of I2 in production or storage of
DIH compound, and thereby solve decrease in purity of DIH
compound or various problems caused by I2.
In order to solve the above problems, the present
inventors intensively searched for a cause of release of I2
in production or storage of DIH compound.
As a result, the present inventors have found that DIH
compound is unstable in a state of wet body, in which a certain
level of liquid component such as water and an organic solvent
is contained, even at an ordinary temperature, and that this
instability causes the aforementioned release of I2. In
addition, the release of I2 from such wet body becomes more

3
remarkable under a comparatively high temperature condition.
Therefore, based on the above knowledge, the present
inventors have found that the decomposition of DIH compound
and the release of I2 accompanying thereto can be prevented
by controlling drying means in production of DIH compound
and temperature condition in storage thereof, and finally
accomplished the present invention.
That is, the present invention provides a production
method for 1,3-diiodohydantoin compound comprising a step
to provide a wet body containing a 1,3-diiodohydantoin
compound, and (1) a step to dry the wet body by contacting
the wet body with heated gas or (2) a step to lyophilize the
wet body.
In addition, the present invention provides a storage
method for a 1, 3-diiodohydantoin compound comprising a step
to store a 1,3-diiodohydantoin compound under a temperature
condition of 15°C or lower.
Further, the present invention provides a
1, 3-diiodohydantoin compound wherein content of released I2
is 1% by mass or less.
According to the present invention, release of I2 during
production or storage of DIH compound can be inhibited, and
thereby decrease in purity of DIH compound or incidence of
various problems caused by I2 can be prevented.
Best Mode for Carrying Out the Invention
A first aspect of the present invention relates to a
production method for DIH compound. Specifically, firstly
a wet body containing a DIH compound is provided. Subsequently,
(1) the wet body is dried by contacting the wet body with
a heated gas, or (2) the wet body is lyophilized.
As described above, it has been found out that DIH compound

4
is unstable in a state of wet body, in which a certain level
of liquid component is contained therein, and the instability
causes the release of I2 as described above. In addition,
it has been also found out that such release of I2 becomes
remarkable under a comparatively higher temperature condition .
In the present invention, a method to inhibit effectively
this release of I2 is provided.
Incidentally, although mechanism of the release of I2
in production or storage of DIH compound has not been
necessarily clarified, a mechanism based on decomposition
of the DIH compound has been presumed. However, suchmechanism
is only a presumption, and even if the release of I2 occurs
via another mechanism, the technical scope of the present
invention is not affected at all.
Hereinafter, the production method of the first aspect
of the present invention will be explained in detail.
Firstly, the first step in the production method of the
first aspect of the present invention, that is, the step in
which a wet body containing a DIH compound is provided will
be described.
In the present invention, "DIH compound" means a compound
represented by the following chemical formula (I):
[Formula 1]

(wherein R1 and R2 are each independently a hydrogen atom or
a Ci-C6 alkyl group).
Way of procurement for the wet body containing a DIH
compound is not particularly limited. The wet body containing

5
a DIH compound may be used by synthesizing according to the
well known technique (e.g. the technique described in the
aforementioned JP-A-2002-30072) or may be used by purchasing
a commercially available product. As a technique to prepare
the wet body containing a DIH compound by oneself, for example,
the technique shown below can be used. However, the following
preparation method is only an example, and it is needless
to say that "wet body containing a DIH compound" prepared
by a technique other than the following mode may be used.
In the present invention, the DIH compound (Chemical
Formula (I)) is prepared, for example, by reacting a hydantoin
compound (Chemical Formula (II)) with iodine monochloride
in the presence of a base in an aqueous solution, as shown
in the following Chemical Reaction Scheme 1.
[Formula 2]

wherein R1 and R2 are as defined above.
In order to prepare the DIH compound according to the
Chemical Reaction Scheme 1, firstly a hydantoin compound
represented by the Chemical Formula (II), which is used as
a raw material, is provided.
[Formula 3]

6
wherein R1 and Rz are as defined above.
As described above, R1 and R2 is each a hydrogen atom
or a Ci-C6 alkyl group. R1 and R2 may be same or different
from each other. In view of yield in the synthesis reaction
and easiness in handling, R1 and R2 are preferably identic-al-
to each other. The alkyl group may be linear, branched or
cyclic. Number of carbon atoms in the alkyl group is 1 to
6, preferably 1 to 2, and more preferably one. Specific
example of the alkyl group includes methyl group, ethyl group,
propyl group, isopropyl group, butyl group, isobutyl group,
s-butyl group, t-butyl group, pentyl group, isopentyl group,
neopentyl group, hexyl group, and the like. An alkyl group
other than these may also be used. Among them, preferably
both of R1 and R2 are methyl groups, from the viewpoints of
industrially moderate price and easy availability.
Way of procurement for the hydantoin compound (II) is
not particularly limited. The hydantoin compound may be used
by synthesizing according to the well known technique or may
be used by purchasing a commercially available hydantoin
compound.
Iodine monochloride is a compound represented by the
chemical formula of "IC1", and highly reactive due to
containing iodine of (oxidation number + 1) , and used in various
synthetic reactions as an iodizing agent.
Way of procurement for iodine monochloride (IC1) is also
not particularly limited. Iodine monochloride may be used
by synthesizing according to the well known technique or may
be used by purchasing commercially available iodine
monochloride. Incidentally, as a technique to synthesize
iodine monochloride by oneself, for example, a technique is
exemplified, in which chlorine is passed over iodine, then
liquefied and distilled. It is needless to say that iodine

7
monochloride synthesized by other technique may also be used.
The reaction of a hydantoin compound and iodine
monochloride is carried out in the presence of a base. This
base acts as a catalyst in the reaction system containing
a hydantoin compound and iodine monochloride.
Specific mode of the base is not particularly limited,
and a base which commonly used in such synthetic reaction
can be similarly used. An example of the base includes, for
example, hydroxides, carbonate salts and the like of alkali
metals / alkaline earth metals such as sodium hydroxide,
potassium hydroxide, sodium carbonate, sodium hydrogen
carbonate, potassium carbonate, potassiumhydrogen carbonate,
and the like. It should be noted that these bases may be used
alone or in combination of two or more kinds.
The above reaction is carried out in an aqueous solution,
but a solvent other than water may be included therein. For
example, amide type solvents and ester type solvents can be
included.
Compounding ratio of each component in the above reaction
is not particularly limited, and conventionally known
knowledge (in particular, aforementioned JP-A-2002-30072)
can be referred to as appropriate.
After completion of the above reaction, components other
than DIH compound are removed from the reaction system. By
this operation, a solution of DIH compound can be obtained.
Subsequently, most of the solvent contained in the solution
is removed. By this operation, a "wet body containing a DIH
compound" can be prepared. However, the step in which solvent
is removed, may be carried out before removing the components
other than the DIH compound.
The technique to remove the components other than DIH
compound is not particularly limited, and, for example, a

8
technique such as filtration, recrystallization and
extraction, and combination thereof can be exemplified.
Other technique may also be used.
In addition, the technique to remove most of the solvent
from the- solution containing DIH compound.-is also not
particularly limited, and, for example, a technique such as
filtration, centrifugal separation and decantation, and
combination thereof can be exemplified. Other technique may
also be used.
In this regard, the "wet body containing a DIH compound"
to be provided in this step is composed of a DIH compound,
a solvent, and in some case a small amount of impurity, but
content of the solvent in the wet body is not particularly
limited. As an example, content of solvent is around 8 to
30% by mass to total amount of the wet body. More solvent
may be contained in the wet body, but too high content of
the solvent could result in prolonged drying time leading
to rise of production cost.
Hereinafter, characteristic steps in the production
method of the present invention will be explained.
As described above, in the production method of the
present invention, regarding the resultant "wet body
containing a DIH compound", (1) the wet body is dried by
contacting the wet body with a heated gas, or (2) the wet
body is lyophilized.
Firstly, the technique (1) is explained in detail.
In the technique (1), the "wet body containing a DIH
compound" prepared in the above is dried by contacting the
wet body with a heated gas. Namely, in the technique (1),
so called "fluidized drying" is employed.
Conventionally, as a technique to dry the wet body
containing a DIH compound, an industrially common drying

9
method had been employed. Specifically, drying method by
heating under reduced pressure, e.g. using a conical dryer,
drying method by heating under ordinary pressure, e.g. using
a plate column dryer, and the like had been employed. However,
the-present inventors have found out that a part of the wet .
body containing a DIH compound decomposes and I2 is released
by these methods. Specifically, when a wet body of a DIH
compound (5,5-dimethyl body) containing 2 to 15% of water
is heated at 40 °C for 3 hours, 4 to 6% of the compound is
decomposed to release I2 . Also, when the wet body is similarly
heatedat 70°C for 3 hours, 9 to 30% of the compound is decomposed.
As a result, such problems as decrease in purity of DIH compound,
and coloration or corrosion of material or equipment by
released I2, and increased risk for operators could occur.
On the contrary, according to the technique as described
above, the release of I2, which had conventionally been a
problem in drying a wet body, can be inhibited to the minimum.
In this regard, although mechanism, by which a difference
in levels of released I2 arises between the conventional drying
technique and the drying technique of the present invention,
has not been perfectly clarified, it is considered that the
DIH compound which is instable to heat may decompose because
the wet body is exposed at a high temperature condition over
a long period of time in such unit of several hours in the
conventional drying technique. Consequently, according to
the production method of the present invention, not only the
release of I2 in production of DIH compound can be inhibited
to the minimum, but also heating time can be reduced and rapid
production is enabled, and this can contribute to reduction
in production cost. However, the technical scope of the
present invention should be determined based on the
description in the claims, and the technical scope is not

10
affected by the mechanism.
Specif ic mode of the f luidized drying is not particularly
limited, and conventionally well known knowledge in the
synthesis field of chemical compounds can be referred to as
appropriate. Hereinafter, preferable mode in the fluidized
drying is exemplified. However, fluidized drying is not
limited only to the following mode.
In the present invention, "heated gas" means a gas having
a temperature level at which a wet body containing a DIH
compound can be dried by contacting with the wet body. The
heated gas is preferably a gas which does not react with the
DIH compound. Specific kind of the heated gas includes, for
example, nitrogen gas, argon gas, helium gas, air gas, and
mixed gas thereof, but kind of the heated gas is not limited
to them. As the heated gas, air gas is preferably used.
Temperature of the heated gas in contact with
aforementioned wet body is not particularly limited, and can
be decided taking physical properties of the DIH compound
to be prepared and general knowledge in fluidized drying into
consideration comprehensively. However, temperature of the
heated gas is preferably 20 to 200°C, more preferably 40 to
170°C, and furthers more preferably 90 to 130°C. Too low
temperature of the heated gas requires prolonged drying time
as a result of insufficient amount of heat, or could fail
to dry up to a desired liquid content. On the contrary, too
high temperature of the heated gas could give rise to
deterioration (decomposition andmelting) of the DIH compound
due to overheating.
Flow rate of the heated gas in contact with aforementioned
wet body is also not particularly limited, but preferably
O.ltolO.O m/sec, more preferably 0.3to5.0 m/sec, and further
more preferably 0.5 to 3.0 m/sec. Too low flow rate of the

11
heated gas requires prolonged drying time as a result of
insufficient contact of the heated gas with the whole wet
body, or could fail to dry up to a desired liquid content.
On the contrary, too high flow rate of the heated gas could
make collection of the-wet body difficult because of-excessive .
scattering of the wet body.
Next, the technique (2) is explained in detail.
In the technique (2), the "wet body containing a DIH
compound" provided as described above is lyophilized. By such
technique, the release of ±2, which had conventionally been
a problem in drying of the wet body, can also be inhibited
to the minimum. In this regard, mechanism by which the
conventional problem is solved by employing lyophilization
is presumed to be similar to the case of the aforementioned
fluidized drying.
Thus, the techniques (1) and (2) are the same in the
point to inhibit the release of I2 in drying the wet body to
the minimum.
"Lyophilization" is also referred to as lyophilize, and
a technique in which a wet body is dried by freezing quickly
the wet body at a temperature of the freezing point or below,
and removing a solvent of the frozen body by sublimation by
reducing pressure to a level of the vapor pressure of the
solvent or below.
Specific mode of the lyophilization is not particularly
limited, and conventionally well known knowledge in the
synthesis field of chemical compounds can be referred to as
appropriate. Hereinafter, a preferable mode in the
lyophilization is exemplified. However, the lyophilization
is not limited to the following mode.
Firstly, a wet body containing a DIH compound is cooled
down quickly to a prescribed temperature. By this operation,

12
the aforementioned wet body is frozen. Temperature to be
attained by the quick cooling is not particularly limited,
but the wet body may be cooled down to preferably -196 to
0°C, and more preferably -100 to -20°C.
After that, the frozen body is placed in a reducedpressure .
In this case, pressure condition is not particularly limited,
and pressure may be reduced to a level which is necessary
to remove a solvent contained in the wet body. As an example,
pressure may be reduced to around 10tol,500Pa, and preferably
100 to 700 Pa.
When the wet body is driedby the technique (2) , preferably
a solvent is further added to the "wet body containing a DIH
compound" provided as described above to prepare a wet body
in a slurry state, then the resultant wet body in a slurry
state is lyophilized by the technique described above.
According to this mode, such desirable effect that sublimation
from inside is facilitated by freezing of whole wet body in
a slurry state compared with the case when the wet body provided
as described above is simply lyophilized as it is, can be
obtained.
In such mode, the solvent to be added to the wet body
when the wet body in a slurry state is prepared is not
particularly limited. However, a solvent, which does not
react with the DIH compound and is easy to sublime in the
following lyophilization, is preferably used. An example of
the solvent to be added includes, besides water, ethyl acetate,
n-butyl acetate, N, N-dimethylformamide, and the like. Among
them, preferably water is further added from the viewpoints
of moderate price, easy-handling, and being suitable for
lyophilization.
Addition amount of the solvent when the solvent is added
to the wet body is also not particularly limited, but the

13
solvent may be added so that total content of the solvent
to the whole amount of the wet body in a slurry state becomes
preferably 30 to 70% by mass, and more preferably 50 to 60%
by mass.
According to the production method of the first aspect
of the present invention, by any technique of (1) and (2),
the release of I2 in production of DIH compound can be inhibited
to the minimum, and conventional various problems associated
with the release of I2 can be solved. In other words, according
to the production method of the first aspect of the present
invention, a DIH compound which has a more reduced content
of released I2 than before can be produced. Namely, a second
aspect of the present invention is a DIH compound which has
a reduced content of free I2. In this case, content of the
free I2 in the DIH compound of the second aspect of the present
invention is preferably 1% by mass or less, more preferably
0.8% by mass or less, further more preferably .0.4% by mass
or less, and particularly preferably 0.2% by mass or less.
As described above, since the free I2 is an impurity to cause
various problems, lower content of the free I2 in the resultant
DIH compound is more preferable . However, the technical scope
of the production method of the first aspect of the present
invention is not necessarily limited only to a mode in which
a DIH compound containing such amount of the free I2 is produced.
In some case, a DIH compound containing the free I2 in an amount
out of this range may be produced. In addition, the technical
scope of the DIH compound of the present invention is not
necessarily limited only to the mode in which the DIH compound
is produced by the production method of the first aspect of
the present invention, and in some case, the DIH compound
may be produced by other production method. In this regard,
as a content of free I2 in the DIH compound produced, a value

14
measured by the technique described in Example below should
be employed.
In addition, in the DIH compound of the second aspect
of the present invention, besides the content of free I2, less
content of water is also more preferable. This is because
decomposition of DIH compound and release of I2 accompanying
thereto in production and storage of DIH compound occur more
easily when water content is higher. Specifically, content
of water in the DIH compound of the second aspect of the present
invention is preferably 6% by mass or less, more preferably
5% by mass or less, further more preferably 3% by mass or
less, and particularly preferably 1% by mass . Consequently,
when the wet body containing a DIH compound is subjected to
fluidized drying (1) or lyophilization (2) in the production
method of the first aspect of the present invention, drying
conditions may be controlled so that content of water in the
resultant DIH compound becomes a value in the above range.
Application of the DIH compound of the second aspect
of the present invention is not particularly limited, but
it can be employed, for example, in applications such as a
sensitive material of photography or an iodizing agent or
an oxidizing agent in production processes for medical drugs,
agricultural chemicals, chemicals, or the like.
As described above, the production method for DIH
compound was explained as the first aspect of the present
invention, and the DIH compound itself was also explained
as the second aspect of the present invention. The present
invention also provides a storage method for DIH compound
as a third aspect of the present invention.
The storage method of the third aspect of the present
invention has been made based on the knowledge that
decomposition of DIH compound and release of I2 accompanying

15
thereto occurs more easily under a comparatively higher
temperature condition.
Namely, the third aspect of the present invention is
a storage method comprising a step in which a DIH compound
is stored under a temperature condition of-15°C or lower.
The DIH compound to be used in the storage method of
the third aspect of the present invention is not particularly
limited, and conventionally well known DIH compound can be
used. However, in view of sufficient inhibition of
decomposition of DIH compound and release of I2 thereby, the
DIH compound produced by the production method of the first
aspect of the present invention or the DIH compound provided
as the second aspect of the present invention is preferably
used. Since specific mode of these DIH compounds is as
described above, detailed explanation will be omitted here.
In the third aspect of the present invention, the DIH
compound is stored under a temperature condition of 15°C or
lower, preferably 10°C or lower, and more preferably 5°C or
lower. By this operation, the decomposition of DIH compound
and the release of I2 thereby can be inhibited.
In the third aspect of the present invention, specific
mode other than the storage under the above temperature
condition is not particularly limited, and conventionally
well known knowledge about storage of chemical compounds can
be referred to as appropriate . In this regard, in the present
invention, concept of "storage" includes not only a mode when
a DIH compound is placed in one position, but also a mode
such as "transportation" in which a DIH compound is transferred
among various places until it is used for a prescribed
application.
In the third aspect of the present invention, humidity
condition in the storage of DIH compound is not particularly

16
limited, but generally it is preferable to be stored under
a low humidity condition. Specifically, relative humidity
(RH) in an atmosphere of storage place is preferably 50% or
less, and more preferably 301 or less.
In the storage method of the third aspect of-the present
invention, DIH compound is usually stored in a packed state
in a prescribed container. Specific mode of the container
is also not particularly limited, and conventionally well
known storage containers in storage field of chemical
compounds can be employed as appropriate. Constituent
material for the storage containers includes industrially
commodity type of resins, and specifically includes
polyethylene, polypropylene, polystyrene, polyester,
polyvinyl chloride, polyvinylidene chloride, and the like.
Shape of the storage containers is also not particularly
limited, and shapes such as bag-like, box-like, drum-like,
and the like are exemplified.
Even by the storage method of the third aspect of the
present invention, a very small amount of I2 can be released
from DIH compound during storage. Consequently, the storage
container is preferably those having a hermetically sealing
function. From such viewpoint, as a constitutional material
for the storage containers, polyvinylidene chloride /
polyethylene composite material and
high-barrier-performance polymers are preferably employed.
Metal containers with resin lining can also be used as the
storage containers . However, in such mode, it should be noted
that the metal material could be corroded by penetration of
a very small amount of free I2 when storage is continued for
an extremely long period.
In the storage method of the third aspect of the present
invention, the temperature condition is not necessarily in

17
the above range through whole course of storage period, but
the temperature condition may be in the above range in about
100% of the period except the period when the DIH compound
is temporally stored under a temperature condition of around
ordinary temperature because of transfer or the like.
The storage method of the third aspect of the present
invention may be combined with the production method of the
first aspect of the present invention.
For example, when a DIH compound is premised to be stored
using the storage method of the third aspect of the present
invention, it is convenient to produce the DIH compound
according to the production method of the first aspect of
the present invention, then to store directly the DIH compound
by the storage method of the third aspect of the present
invention.
Examples
Hereinafter, the present invention will be explained
more in detail using Examples and Comparative Example, however,
the technical scope of the present invention is not limited
to the following modes.

As a wet body containing a DIH compound,
5, 5-dimethyl-l, 3-diiodohydantoin (20 kg) containing n-butyl
acetate (2% by mass) and water (13% by mass) was provided.
The wet body provided as described above was charged
into a fluidized dryer. The wet body was dried by contacting
the wet body with air of 110°C as a heated gas in a flow rate
of 1 m/sec for 30 minutes to obtain pale yellow crystalline
powder of 5,5-dimethyl-l,3-diiodohydantoin in a purity of
98% or more.
After that, contents of free I2 and water in the resultant

18
powder were determined. As a result, content of free I2 was
0.2% by mass or less, and content of water was 1% by mass
or less. In this regard, the contents of free I2 and water
were measured by the following techniques.
Pleasuring method for contentOt "free I2>
According to "First method: Method by heating drying
under atmospheric pressure" in JIS-K0067"1992 4.1.4(1)
described in "2004-edited JIS Handbook, 49, Chemical
Analysis", a sample was heated at 60°C for 2 hours under the
atmospheric pressure, and decrease in mass was measured to
obtain a content of free I2.

According to "First method: Method by heating drying
under atmospheric pressure" in JIS-K0067"1992 4.1.4(1)
described in "2004-edited JIS Handbook, 49, Chemical
Analysis", the sample, which was used for measuring content
of free I2, was dried at 105°C for 2 hours under the atmospheric
pressure, and decrease in mass was measured to obtain a content
of water.

As a wet body containing a DIH compound,
5, 5-dimethyl-l, 3-diiodohydantoin (50 g) containing water (8%
by mass) was provided.
The wet body provided as described above was charged
into a lyophilizer, then cooled down to -80°C to freeze the
wet body. Subsequently, the resultant frozen body was dried
by sublimation at 20°C for 22 hours under reduced pressure
condition of 270 Pa to obtain pale yellow crystalline powder
Of 5,5-dimethyl-l,3-diiodohydantoin in a purity of 95% or
more.
After that, contents of free I2 and water in the resultant
powder were determined. As a result, content of free I2 was

19
0.2% by mass or less, and content of water was 5% by mass.

As a wet body containing a DIH compound,
5,5-dimethyl-l,3-diiodohydantoin (21g) containing water (8%
by mass) was provided.
Water (22 g) as a solvent was further added to the wet
body provided as described above to prepare a wet body in
a slurry state.
The wet body in a slurry state as described above was
charged into a lyophilizer, and cooled down to -80°C to freeze
the wet body. Subsequently, the resultant frozen body was
dried by sublimation at20°Cforl4 hours under reduced pressure
condition of 270 Pa to obtain pale yellow crystalline powder
of 5, 5-dimethyl-l,3-diiodohydantoin in a purity of 98% or
more.
After that, contents of free I2 and water in the resultant
powder were determined. As a result, content of free I2 was
0.2% by mass or less, and content of water was 1% by mass.

The pale yellow crystalline powders of
5,5-dimethyl-l,3-diiodohydantoin obtained in Examples 1 to
3 described above were stored each in hermetically sealed
state in a polyethylene-made container at 5°C. As a result,
no change in appearance of the compound or content of released
I2 was observed even after 6 months of time course.

As a wet body containing a DIH compound,
5,5-dimethyl-l,3-diiodohydantoin (200 kg) containing
n-butyl acetate (2%" by mass) and water (13% by mass) was
provided.
The wet body provided as described above was charged
into a 1,000 L conical dryer, then, dried at 40 to 70°C under

20
a reduced pressure of 2,700 to 5,300 Pa.
As a result, decomposition of
5,5-dimethyl-l,3-diiodohydantoin started to proceed after
about 4 hours from the start of drying, and I2 was released.
And after about 8 hours from the start of drying, vacuum line
was blocked up by the released I2. From then on, drying by
the conical dryer could not be continued. In this case, the
resultant 5, 5-dimethyl-l, 3-diiodohydantoin was red crystal,
and contained 2% by mass or more of released I2 and 8% by mass
of water, and could not be used practically. In addition,
this red crystal was stored in a hermetically sealed state
in a polyethylene-made container at5°C. Releaseofl2further
proceeded within several weeks, and such appearance that
released I2 deposited in the upper part of the container was
observed.

As aDIHcompound, 5,5-dimethyl-l,3-diiodohydantoin (20
kg) (content of free I2: 0.2% by mass, content of water: 1%
by mass) was provided.
On the other hand, as storage containers, two bags made
of polyvinylidene chloride / polyethylene composite material
were provided.
In each storage container provided as described above,
the DIH compound (10 kg each) also provided as described above
was packed, then each bag was heat-sealed after the packing.
After that, one of the storage containers packed with
the DIH compound was stored at 5°C (Example), and the other
was stored at 25°C (Comparative Example). As a result, in
the case of Example, no change in quality (specifically,
content of released I2) of the DIH compound was observed even
after one year or more of storage. On the contrary, in the
case of Comparative Example, decomposition of the DIH compound

21
started to release I2 after 2 months of storage, and coloration
of the bag was observed.
From the results described above, it is indicated that
decomposition of DIH compound and release of I2 thereby in
drying can be inhibited and a high quality of DIH compound
which is easy to handle and superior in storage stability
can be produced by subjecting wet body containing a DIH compound
to fluidized drying or lyophilization. In addition,
according to the storage method of the present invention,
it is indicated that the DIH compounds are kept in high quality
over long term.
Thus, according to the present invention, release of
I2 in production or storage of DIH compound can be inhibited,
and thereby prevent ion of decrease in purity of the DIH compound
or occurrence of various problems caused by I2 can be expected.
It should be noted that, the present invention is based
on JP Application No. 2005-25557 filed on 2nd September, 2005,
and the content of disclosure has been incorporated herein
in its entirety by reference.

22
WHAT IS CLAIED IS:
1. A production method for 1,3-diiodohydantoin compound
comprising:
a step to provide a wet body comprising a
1,3-diiodohydantoin compound and
a step to dry the wet body by contacting the wet body
with heated gas.
2. A production method for 1,3-diiodohydantoin compound
comprising a step to provide a wet body comprising a
1,3-diiodohydantoin compound and a step to lyophilize the
wet body.
3. The production method according to claim 2, comprising
further a step to prepare a wet body in a slurry state by
adding a solvent to the provided wet body, wherein the wet
body is the wet body in a slurry state.
4. The production method according to any one of claims
1 to 3, wherein the 1,3-diiodohydantoin compound is
5,5-dimethyl-l,3-diiodohydantoin.
5. A storage method for 1,3-diiodohydantoin compound
comprising a step to store a 1,3-diiodohydantoin compound
under a temperature condition of 15°C or lower.
6. The storage method according to claim 5, wherein the
1,3-diiodohydantoin compound is
5,5-dimethyl-l,3-diiodohydantoin.
7. A 1,3-diiodohydantoin compound, wherein content of
released I2 is 1% by mass or less.
8. The 1, 3-diiodohydantoin compound according to claim 7,
wherein further content of water is 6% by mass or less.
9. The compound according to claim 7 or 8, wherein the
1,3-diiodohydantoin compound is
5,5-dimethyl-l,3-diiodohydantoin.

The present invention provides a means which can inhibit
release of I2 in production or storage of 1, 3-diiodohydantoin
compound, and thereby solve decrease in purity of the compound
and various problems caused by I2.
The present invention provides a production method for
1,3-diiodohydantoin compound comprising a step to prepare
a wet body containing a 1,3-diiodohydantoin compound, and
(1) a step to dry the wet body by contacting the wet body
with heated gas or (2) a step to lyophilize the wet body,
a storage method for 1, 3-diiodohydantoin compound comprising
a step to store a 1,3-diiodohydantoin compound under a
temperature condition of 15 °C or lower, and a
1, 3-diiodohydantoin compound wherein content of released I2
is 1% by mass or less.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=gaKQeufCJPcETIT5dt8D+A==&loc=wDBSZCsAt7zoiVrqcFJsRw==

« Previous Patent

Next Patent »

Patent Number

269266

Indian Patent Application Number

858/KOLNP/2008

PG Journal Number

42/2015

Publication Date

16-Oct-2015

Grant Date

13-Oct-2015

Date of Filing

27-Feb-2008

Name of Patentee

NIPPOH CHEMICALS CO., LTD.

Applicant Address

8-15, 4-CHOME, NIHONBASHI-HONCHOU, CHUO-KU, TOKYO JAPAN

Inventors:

#	Inventor's Name	Inventor's Address
1	INOUE, LAZUHISA	C/O NIPPOH CHEMICALS CO., LTD., 1240, MATSUMARU, ISUMI-SHI, CHIBA 298-0104
2	MIYAZAWA, TAKAAKI	C/O NIPPOH CHEMICALS CO., LTD., 3-3, NIHONBASHI-MUROMACHI 3-CHOME, CHUO-KU, TOKYO 103-0022
3	HANAMURA, YUKIHIKO	C/O NIPPOH CHEMICALS CO., LTD., 1240, MATSUMARU, ISUMI-SHI, CHIBA 298-0104

PCT International Classification Number

C07D 233/82

PCT International Application Number

PCT/JP2006/317113

PCT International Filing date

2006-08-30

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	2005-255557	2005-09-02	Japan