JPH0482137B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for purifying perfluorinated nitrogen-containing compounds useful in the fields of medicine, agrochemicals, etc., and particularly relates to a method for separating and removing partially fluorinated compounds remaining in the crude product. [Prior Art] A perfluoro nitrogen-containing compound can be produced by a method suitable for the nitrogen-containing compound corresponding to this perfluoro nitrogen-containing compound, such as a direct fluorination method, a cobalt fluorination method,
It is produced by fluorination using electrolytic fluorination method, etc., but regardless of whether it is produced by any of these methods,
The resulting product contains impurities such as partially fluorinated products that are insufficiently fluorinated and unsaturated compounds that partially have unsaturated bonds remaining. Therefore, in the past, as a method for purifying perfluorinated nitrogen-containing compounds, particularly for separating and removing partially fluorinated compounds and unsaturated compounds, for example, crude perfluorinated nitrogen-containing compounds obtained by fluorination were used.
After heating under reflux for 5 days in a mixed solution of equal amounts of 70% sodium hydroxide aqueous solution and diisobutylamine, dilute sulfuric acid, concentrated sulfuric acid, saturated sodium bicarbonate aqueous solution, 90% acetone aqueous solution containing 3% potassium iodide, and water were added. The cleaning process is carried out in sequence. [Problems to be Solved by the Invention] However, the above-mentioned alkali/amine treatment alone does not remove the partially fluorinated substances and unsaturated substances contained in the crude perfluorinated nitrogen-containing compound. It is difficult to separate and remove saturated compounds to a satisfactory extent, and there has been a need to develop a method that can more completely separate and remove them. [Means for Solving the Problems] The present invention was created in view of this point of view, and it is possible to remove partially fluorinated compounds and unsaturated compounds contained in crude perfluorinated nitrogen-containing compounds by a simple method. Moreover, it provides a purification method that can separate and remove as much as possible. That is, the present invention provides a method for separating and removing partially fluorinated compounds remaining in a crude product of a perfluoro nitrogen-containing compound, in which the crude product is heat-treated at 60°C or higher in the presence of an alcoholate solution. It is a crude method. In the present invention, the perfluorinated nitrogen-containing compound to be crudely produced may be one produced by any conventionally known fluorination method,
Furthermore, it may be a cyclic compound or an acyclic compound. It may be a perfluoro nitrogen-containing alicyclic compound in which the atoms forming the ring are composed only of carbon, or a perfluoro heterocyclic compound containing a nitrogen atom as the atoms forming the ring. Specific examples of the perfluoro nitrogen-containing alicyclic compound include perfluoro aminodecalin derivatives, and specific examples of the perfluoro heterocyclic compound include perfluoropiperidine derivatives, Examples include perfluorodecahydroquinoline derivatives, perfluorodecahydroisoquinoline derivatives, and perfluorooctahydroindole derivatives. In addition, specific examples of acyclic perfluoro nitrogen-containing compounds include perfluorotributylamine,
Perfluorinated linear amines such as perfluorodibutylmethylamine can be mentioned. Preferably, it is a cyclic or acyclic perfluoroamine compound. In the present invention, the crude perfluorinated nitrogen-containing compound to be purified may be freshly produced, but from the viewpoint of efficiency, it may be pretreated to remove some of the impurities. It is advantageous to leave it there. Such pretreatment can be carried out by conventionally known methods such as distillation, crystallization, extraction, etc., but it is preferable to carry out an alkali/amine treatment alone or in addition to each of the above methods, The content of partially fluorinated compounds and unsaturated compounds contained in the crude product should be 2% by weight or less, preferably 0.5% by weight.
Do the following. Conventionally known methods may be used for this alkali/amine treatment, for example, 70%
A method of heat treatment for a long time in the presence of a mixed solution of an alkali such as an aqueous potassium hydroxide solution and an amine such as diisobutylamine can be adopted. Here, sodium hydroxide salt, potassium hydroxide, etc. can be typically used as the alkali, and examples of the amine include alkyl amines such as dipropylamine, cyclic amines such as piperidine, etc. can. After this alkali/amine treatment, a 90%
It is best to wash with acetone aqueous solution or water. In the method of the present invention, a crude perfluorinated nitrogen-containing compound is heat-treated in the presence of an alcoholate solution. There are no particular limitations on this alcoholate solution, but preferably an alcoholate in which an alkoxy group having 1 to 12 carbon atoms, more preferably 1 to 5 carbon atoms, is bound to an alkali metal such as sodium, potassium, or lithium, in a suitable solvent, For example, those obtained by dissolving in alcohol can be mentioned. The alcohol used to produce the alcoholate and the alcohol used to dissolve it may be different, but the alcoholate solution obtained by using excess alcohol when producing the alcoholate can be used as is. is advantageous. The alcoholate concentration in this alcoholate solution is usually 1 to 50% by weight, preferably 5 to 30% by weight. The heating temperature when the crude perfluorinated nitrogen-containing compound is heat-treated with the alcoholate solution is 60°C or higher, preferably 100°C or higher. This heat treatment is preferably carried out under reflux conditions using an alcoholate solution having a boiling point of 60° C. or higher that does not require pressurization or the like. The treatment time is usually 0.5 hours or more, preferably 1 to 30 hours. Furthermore, the amount of the alcoholate solution used varies depending on the type of perfluorinated nitrogen-containing compound, the content of partially fluorinated compounds and unsaturated compounds in the crude product, the type of alcoholate solution used, etc. The amount is usually 0.01 to 5 parts by weight, preferably 0.1 to 1 part by weight. The above alcoholate treatment can of course be carried out using the alcoholate solution alone, but it can also be carried out by adding an amine such as diisobutylamine to the alcoholate solution. The amine may be added at the beginning of the alcoholate treatment, it may be added during the alcoholate treatment, or the amine may be added after the alcoholate has been separated and removed. good. The amount of amines used for this purpose is not particularly limited, but is usually 0.05 to 1 part by weight per 1 part by weight of the crude product. By adding these amines, the removal rate of partially fluorinated compounds and unsaturated compounds can be improved. The treated solution obtained by the alcoholate treatment is washed with an acid aqueous solution, an alkaline aqueous solution, water, etc., as necessary. The perfluorinated nitrogen-containing compound is purified by a method, adsorption method, etc., and a perfluorinated nitrogen-containing compound is obtained from which impurities such as partially fluorinated compounds and unsaturated compounds have been separated and removed as much as possible. [Function] According to the method of the present invention, impurities are made heavier, decomposed, and undergo other reactions, and can be easily separated and removed by methods such as distillation. Particularly, partially fluorinated substances are 0.2
If the amount is reduced to less than 0.1% by weight, it can be treated by ordinary means such as distillation.
The content can be reduced to below the detection limit in IR analysis. [Example] Hereinafter, the method of the present invention will be specifically explained based on Examples and Comparative Examples. Example 1 Perfluoro-N-methyldecahydroisoquinoline (FMIQ product) obtained by fluorinating N-methyldecahydroisoquinoline, 8N potassium hydroxide aqueous solution, and diisobutylamine were mixed in a volume ratio of 1:
After mixing at a ratio of 1:1 and heating under reflux for 5 days,
Wash with sulfuric acid, then water, and then with water and a 90% acetone aqueous solution containing 3% potassium iocanide.
Obtained FMIQ. 10 g of a methanol solution of 28% sodium methylate was added to 20 g of this crude FMIQ, heated under reflux for 5 hours, left to stand, and a small amount of FMIQ in the lower layer was collected, and its component composition was determined by gas chromatography analysis. The results are shown in Table 1. Example 2 Using 10 g of 18% sodium ethylate as the alcoholate solution, alcoholate treatment was performed in the same manner as in Example 1, and the component composition of alcoholate-treated FMIQ was determined. The results are shown in Table 1. Next, after separating and removing the sodium ethylate used in the alcoholate treatment, 5 g of diisobutylamine was added, and the mixture was heated under reflux for 3 hours, left to stand, and a small amount of FMIQ in the lower layer was collected to determine its component composition. The results are shown in Table 1. Example 3 Alcoholate treatment was carried out in the same manner as in Example 1, using 30 g of 6% potassium t-butyrate as the alcoholate solution. The results are shown in Table 1. As is clear from the results shown in Table 1, the partially fluorinated product, which is difficult to separate, is reduced to 0.2% by weight or less, and by distilling this, it can be purified to a level where it is virtually undetectable. In addition,
Although it is difficult to separate and remove FMIQ isomer using the method of the present invention, this FMIQ isomer has similar properties to the target FMIQ, and in many cases even a small amount remains after distillation. No problem.

〔Effect of the invention〕

According to the method of the present invention, partially fluorinated compounds and unsaturated compounds contained in a crude perfluorinated nitrogen-containing compound can be separated and removed by a simple method.

Claims (1)

[Scope of Claims] 1. In separating and removing the partially fluorinated product remaining in the crude perfluorinated nitrogen-containing compound, the crude product is heat-treated at 60°C or higher in the presence of an alcoholate solution. A method for purifying perfluorinated nitrogen-containing compounds. 2. The method for purifying a perfluorinated nitrogen-containing compound according to claim 1, wherein the crude product is pretreated by heat treatment in the presence of an aqueous alkali hydroxide solution and an amine solution. 3. The method for purifying a perfluoro nitrogen-containing compound according to claim 1 or 2, wherein the perfluoro nitrogen-containing compound is a perfluoro cyclic amine compound.