JPS6152818B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to N.N'-bis(2-chloroethyl)
The present invention relates to a method for producing oxalic acid amide. For more details,
The present invention relates to N.N-bis(2-hydroxyethyl)
The present invention relates to a method for producing N.N'-bis(2-chloroethyl)oxalamide by chlorinating oxalamide with hydrogen chloride. N・N′-bis(2-chloroethyl)oxalamide is useful as an intermediate in the production of 2・2′-△ ² -dioxazoline, and 2・2′-△ ² -dioxazoline has a carboxyl group, etc. Because it easily reacts with , its usefulness is attracting attention as a curing agent for powder coatings and as a crosslinking agent for epoxy resins and the like. Conventionally, N.N'-bis(2-chloroethyl)oxalamide has been prepared by a method in which N.N'-bis(2-hydroxyethyl)oxalamide is reacted with thionyl chloride (J.Am.Chem.Soc. 60 2152 ( It is known that it can be produced by a method involving the reaction of oxalyl chloride with ethyleneimine (see J. Chem. Soc. 1962, 1481). However, these methods have problems such as reaction operation, toxicity and cost of raw materials, and environmental pollution, making it difficult to use them as production methods on a corporate scale. Generally, aliphatic hydroxy compounds can be chlorinated with hydrochloric acid. However, N・N′-bis(2-
When hydroxyethyl)oxalamide is reacted with hydrochloric acid, the amide bond decomposes, and the desired chlorinated N·N'-bis(2-chloroethyl)oxalamide cannot be obtained at all. Furthermore, even if hydrogen chloride gas is used instead of hydrochloric acid, there is a problem that a portion of the amide bond is decomposed by the water produced by chlorination, resulting in a significantly poor yield. As a result of research to solve these problems, the present inventors have discovered that by reacting hydrogen chloride with N.N'-bis(2-hydroxyethyl)oxalamide, the desired N.N'-bis(2-chloroethyl) ) It has been discovered that chlorination can proceed efficiently by using a phenolic solvent as a reaction solvent when synthesizing oxalic acid amide, and the present invention has been achieved. That is, the present invention involves reacting N·N'-bis(2-hydroxyethyl)oxalamide with a chlorinating agent to produce N·N'-bis(2-chloroethyl)oxalamide. A method for producing N.N'-bis(2-chloroethyl)oxalamide, characterized in that it is carried out in the presence of a solvent and hydrogen chloride is used as the chlorinating agent. In the present invention, the chlorination reaction is carried out by dissolving or suspending N.N'-bis(2-hydroxyethyl)oxalamide in a phenolic solvent and introducing gaseous hydrogen chloride at a desired reaction temperature. The phenolic solvent used as a reaction solvent in the present invention is preferably a phenol having a melting point of 100°C or less, such as phenol, m-cresol, o-cresol, p-cresol, o-cresol, or
Chlorophenol, m-chlorophenol, p-
Examples include chlorophenol. These may be used alone or as a mixture of two or more without any problem. The amount of such phenolic solvent used is N・N'-
The amount may be within a range that can dissolve or suspend bis(2-hydroxyethyl)oxalamide, and usually,
1/3 to 20 times the weight of N・N'-bis(2-hydroxyethyl)oxalamide, preferably 1/2
~10 times the weight. Further, a part of these phenolic solvents can be replaced with a hydrophobic solvent, and it is also possible to use a mixture of both.
Examples of such hydrophobic solvents include benzene, toluene, xylene, ethylbenzene, butoidcumene, p-cymene, duurene, tetralin, α-methylnaphthalene, β-methylnaphthalene, decalin, liquid paraffin, and diphenyl ether. Can be mentioned. When a hydrophobic solvent is used in combination, it is preferable to use the hydrophobic solvent in an amount of 5 times or less, particularly an equivalent or less, to the phenolic solvent. Among such hydrophobic solvents, when using together a solvent that can azeotrope with water in the temperature range of 100°C to 200°C, such as toluene, xylene, ethylbenzene, pseudocumene, etc., the type of solvent and its usage ratio should be selected. By this, water produced as a by-product in the reaction can be efficiently removed from the reaction system by azeotropy. Therefore, it is particularly preferable to use such a hydrophobic solvent in combination. The hydrogen chloride used in the present invention is not particularly limited, and may be, for example, one produced by a commercial method or one obtained by dehydration of hydrochloric acid. However, since water or oxygen contained in hydrogen chloride lowers the reaction yield and causes coloration of the product, it is desirable to remove it in advance. Further, for purposes such as reaction control, it may be used as a mixed gas with an inert gas such as nitrogen. The rate of introduction of hydrogen chloride is not particularly limited and may vary depending on the reaction temperature and reaction scale. Alternatively, in a closed reaction system, a certain proportion of hydrogen chloride can be injected under pressure, and then the hydrogen chloride reduced by the reaction can be successively replenished for the reaction. Alternatively, hydrogen chloride can be continuously introduced and reacted. In the present invention, the chlorination reaction is preferably carried out within a temperature range of 60 to 230°C. Even 90~
Preferably it is carried out at a temperature of 200°C, especially 110-190°C. If the temperature is lower than this range, the reaction time will take a long time, and if the temperature is higher than this range, the color of the product or the yield will be significantly reduced, which is not preferable. Further, it is desirable that water by-produced in the reaction is quickly removed from the reaction system, and a low reaction temperature is also preferred from this point of view. Further, the reaction can be carried out by any method such as batch reaction, continuous reaction, sequential reaction, etc. Furthermore, in continuous reaction, unreacted raw materials and/or solvent can be recycled and used. In the present invention, the method of removing water by azeotropy described above is effective in actively removing by-product water and allowing the reaction to proceed in a favorable direction.
Other methods, such as a method of filling the reaction system, gas discharge pipe, or reflux condenser with a dehydrating agent, can also be used. N.N'-bis(2-chloroethyl)oxalamide produced by the method of the present invention can be easily separated as crystals from the reaction solvent in most cases by cooling the reaction system. This N.
N'-bis(2-chloroethyl)oxalamide is a satisfactory intermediate for the synthesis of 2.2'- ^Δ2 -dioxazoline. The present invention will be further explained below with reference to Examples. Examples 1 to 7 Equipped with a thermometer, a hydrogen chloride inlet pipe, a cooler with an azeotropic water removal device and a stirrer with a gas outlet
A 500 ml reactor was charged with N・N'-bis(2-hydroxyethyl)oxalamide and the prescribed amount of the solvent shown in Table 1, and hydrogen chloride gas was stirred at a rate of about 1/min while the solvent was refluxing. Introduced below. The water produced by the reaction was azeotropically distilled off, but the reaction was continued until the production of water almost stopped. The times are shown in Table 1. The obtained reaction product was thoroughly washed with cold methanol, and the crystals were separated by filtration and dried. The obtained crystals are sufficiently pure as they are, but when recrystallized from methylcellosolve and compared with a standard product of N・N'-bis(2-chloroethyl)oxalamide, the melting point, IR,
The NMR spectrum also matched the characteristics of the standard sample. Obtained N・N′-bis(2-chloroethyl)
The yield of oxalic acid amide is shown in Table 1. 【table】

Claims (1)

[Claims] 1 When reacting N.N'-bis(2-hydroxyethyl)oxalamide with a chlorinating agent to produce N.N'-bis(2-chloroethyl)oxalamide, the reaction is carried out in the presence of a phenolic solvent. 1. A method for producing N.N'-bis(2-chloroethyl)oxalic acid amide, which is carried out using hydrogen chloride as the chlorinating agent.