JP3869170B2 - Process for producing 1,1,1,3,3-pentachloropropane - Google Patents

Description

[0001]
[Industrial application fields]
The present invention is useful as a precursor for producing 1,1,1,3,3-pentafluoropropane, which is expected as a foaming agent such as polyolefin, polystyrene, polyurethane foam, polyisocyanurate, or a refrigerant for a turbo refrigerator. The present invention relates to a method for producing 1,1,3,3-pentachloropropane.
[0002]
[Prior art and its problems]
Production of chlorofluorocarbon (CFC) is prohibited as a depleting substance of the ozone layer, and hydrochlorofluorocarbon (HCFC) or hydrofluorocarbon (HFC) is used as an alternative to these substances However, since HCFC has a chlorine atom in the molecule, it has a small amount of ozone depletion ability, and production will be abolished soon.
[0003]
As a method for synthesizing chloropropanes used as a raw material for producing HFCs, propane chlorination reaction, radical addition reaction between chlorinated methanes and olefins having 2 carbon atoms, and similarly chlorinated methanes and 2 carbon atoms. There are known methods based on ion addition reactions such as Friedel-Craft reaction or Prince reaction with olefins. For example, as a method for obtaining a tetrachloroalkane by reaction of an olefinic hydrocarbon and carbon tetrachloride, a method using an organic peroxide as a reaction aid (USP 2,440,800), an organic acid metal salt as a catalyst Alternatively, a method of reacting an inorganic acid metal salt with an amine or the like (Japanese Patent Publication No. 37-18389, Japanese Examined Publication No. 39-28306, Japanese Examined Publication No. 40-19740, Japanese Patent Publication No. 41-20692), copper metal and alkali A method of reacting in the presence of a catalyst comprising a metal halide (Japanese Patent Laid-Open No. 47-31907), a method of reacting in the presence of a catalyst comprising a polyalkoxy compound and iron chloride (Japanese Patent Laid-Open No. 52-59102), and phosphorus A method of reacting in the presence of a catalyst comprising an acid alkyl ester, iron chloride and a nitrile compound (Japanese Patent Laid-Open No. 52-5910) 3)).
[0004]
As a method for producing 1,1,1,3,3-pentachloropropane, a method of reacting vinylidene chloride and chloroform in the presence of a copper amine catalyst (M. Kotora et al., React. Kinet. Catal. Lett., Vol. 44). , 2, 415, 1991), a method of reacting carbon tetrachloride with vinyl chloride in the presence of a copper amine catalyst (M. Kotora et al., J. of Mol. Catal. 77, 51, 1992). , A method of reacting carbon tetrachloride and vinyl chloride in an isopropanol solvent in the presence of a ferrous chloride catalyst (EN Zil'berman et al., J. of Org. Chem. USSR, Vol. 2, p. 2101, 1967). ) Etc. have been reported.
[0005]
Further, the applicant of the present invention is a method for producing 1,1,1,3,3-pentachloropropane by reacting carbon tetrachloride and vinyl chloride in the presence of elemental iron and an aprotic polar organic solvent such as acetonitrile. (JP-A-8-239333).
[0006]
[Means for Solving the Problems]
The inventors of the present invention have intensively studied for the purpose of further improving the method disclosed in JP-A-8-239333. As a result, the reaction system can be further improved in yield by adding chlorine to the reaction system. The inventors have found that the desired 1,1,1,3,3-pentachloropropane is selectively produced, and arrived at the present invention.
[0007]
That is, the present invention is characterized in that carbon tetrachloride and vinyl chloride are reacted with halogen (halogen is chlorine, bromine or iodine), an iron catalyst and an aprotic organic solvent. , 1,3,3-pentachloropropane production method.
[0008]
In the present invention, halogen is used, and bromine and iodine other than chlorine can be used as the halogen. However, it is preferable to use chlorine for economic reasons.
[0009]
The iron used as a catalyst in the method of the present invention is not an iron compound but elemental iron, and steel containing metallic iron, pure iron, soft iron, reduced iron, carbon, or an alloy containing iron as a component, for example, various kinds Stainless steel, ferrosilicon, etc. can be used, powder, grains, lumps, wires, rods, spheres, plates or metal pieces processed into any shape such as distillation packing such as Raschig rings, helices, steel wool, wire mesh , Coils and other irregular metal pieces can be used. However, in alloys containing a large amount of components that do not have catalytic activity other than iron, these components elute in the reaction system or exist as insoluble components. Is preferred.
[0010]
In addition, a metal compound having a co-catalytic action, a metal complex, or the like can be used in combination with the iron catalyst, and examples of a preferable metal as such a metal include group VIII or IB group metal elements of the periodic table. Specific examples include halides such as nickel, iron, cobalt, palladium, ruthenium, copper and silver, oxides, nitrates, acetates and acetylacetone complexes, and are selected from nickel, iron, cobalt and copper. Metal halides are particularly excellent. Examples of such halides include fluorides, chlorides, bromides, and iodides, and chlorides are excellent in terms of reactivity, versatility of materials, and ease of handling. Specifically, ferrous chloride, ferric chloride, nickel chloride, cobalt chloride, cuprous chloride, and cupric chloride can be mentioned as preferable examples.
[0011]
The amount of the iron catalyst used in the present invention is required to be at least 0.001 mol per 1 mol of carbon tetrachloride. However, since the iron catalyst exists as a solid in the reaction system, the reaction vessel becomes large. Except for this, there is no particular inconvenience for the excess amount. Therefore, in batch type reaction or semi-batch type reaction, it is usually 0.001 to 1 mol, preferably 0.005 to 0.8 mol, and more preferably 0.01 to 0.5 mol. In the formula, the excess of iron catalyst is not particularly inconvenient. If the amount of the catalyst is less than 0.001 mol, the reaction yield decreases, which is not preferable. On the other hand, the amount of the co-catalyst is usually 0.001 to 1 mol, preferably 0.05 to 0.5 mol, more preferably 0.01 to 0.1 mol, per 1 mol of carbon tetrachloride. preferable. If the amount of the cocatalyst is less than 0.001 mol, the reaction rate decreases, which is not preferable. The ratio of the promoter used relative to the iron catalyst is not particularly limited because the amount of the iron catalyst is not limited as described above, but it is usually preferably 0.1 or less.
[0012]
Examples of the aprotic polar organic solvent preferably used in the present invention include nitriles, amides and other solvents. Examples of nitriles include acetonitrile, propionitrile, n-butyronitrile, isobutyronitrile, valeronitrile, phenylacetonitrile, benzonitrile, isophthalonitrile, 2-pentenenitrile, and 3-pentenenitrile. Examples of such solvents include dimethylformamide, dimethylacetamide, hexamethylphosphoric triamide and the like, and other solvents include dimethyl sulfoxide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, γ -Butyrolactone and the like, and acetonitrile, dimethylformamide, and hexamethylphosphoric triamide are preferable because of excellent solubility of the metal compound, and acetonitrile is particularly preferable.
[0013]
In the present invention, it is also possible to add an inert solvent to the reaction system as appropriate in order to improve the reactivity and selectivity. In general, the addition of such a solvent is effective in reducing the formation of higher-order vinyl chloride polymer. The addition ratio is not limited and can be appropriately selected. Such a solvent is not limited as long as it is a substance that is inert in the reaction system and does not function as a radical scavenger.
[0014]
The molar composition ratio of aprotic polar organic solvent / carbon tetrachloride in the reaction system is 10/1 to 1/10, preferably 2/1 to 1/2, and particularly preferably around 1/1. Although it is not particularly inconvenient that this ratio is larger than 10/1, it is not preferable because the reactor becomes large, and if it is smaller than 1/10, the reaction rate of carbon tetrachloride or vinyl chloride is not preferable.
[0015]
The required amount of halogen is from 0.1 to 5 mol%, preferably from 0.5 to 2 mol%, based on carbon tetrachloride. Since iron is produced, it is not preferable. When the amount is less than 0.1 mol%, the induction time of the reaction becomes long and the reaction throughput decreases, which is not preferable. When halogen is not present in the reaction according to the present invention, it is presumed that iron as a catalyst may extract iron from ferric halide to form ferrous halide and may extract chlorine from carbon tetrachloride. Therefore, it is considered that carbon tetrachloride commensurate with the amount of iron serving as a catalyst is consumed. Therefore, wasteful consumption of raw material carbon tetrachloride can be avoided by the presence of halogen.
[0016]
The amount of vinyl chloride is preferably equimolar or less than carbon tetrachloride, but is not necessarily limited. If the amount of vinyl chloride is equal to or greater than the equimolar amount, the amount of higher-order polymerization product of vinyl chloride increases, and an excessive amount of vinyl chloride passes through the reactor without being reacted. When the amount is less than the equimolar amount, carbon tetrachloride partially remains unreacted in the reactor, but this can be recovered and recycled from the reaction solution by a known method such as distillation. There is no particular problem.
[0017]
In the method of the present invention, vinyl chloride can be used after diluted with an inert gas. The degree of dilution may be arbitrary, but an increase in the ratio of the dilution gas to vinyl chloride is preferable because the amount of higher-order polymerized vinyl chloride decreases. However, in this case, since the efficiency of the apparatus is lowered, it is usually preferable that the volume ratio of vinyl chloride / dilution gas is about 0.1 to 10. The diluting gas is not limited as long as it is inert in the reaction system and does not function as a radical scavenger. For example, nitrogen, hydrogen, argon, helium, or the like can be used.
[0018]
The reaction temperature depends on the amount of catalyst and promoter added, the amount of aprotic polar organic solvent added, conversion of vinyl chloride, 1,1,1,3,3-pentachloropropane selectivity, catalyst and promoter However, a range of 80 to 150 ° C., more preferably 100 to 120 ° C. is recommended. When the temperature is lower than 80 ° C., the conversion rate is low, and when it exceeds 150 ° C., the pressure in the reactor needs to be increased, which is not preferable. The pressure in the reactor is the sum of the partial pressures of carbon tetrachloride and aprotic polar organic solvent at each temperature, but is usually 0.1 to 5.0 MPa (1 to 50 kg / cm ² ). 3 to 1.5 MPa (3 to 15 kg / cm ² ) is preferable.
[0019]
As an embodiment of the method of the present invention, any of batch reaction, semi-flow reaction, and flow reaction may be used. For example, an iron catalyst and optionally a metal compound and / or metal complex are present in a mixed reaction solution composed of carbon tetrachloride and an aprotic polar organic solvent, and vinyl chloride and halogen are gaseous in it continuously or intermittently. It is desirable to introduce and react. In this case, the halogen may be charged in the reactor in advance, and in that case, only vinyl chloride may be introduced. When continuously introducing vinyl chloride, if the amount introduced is temporarily excessive, the high-molecular-weight product (carbon number 5) produced as a by-product is unfavorably increased. It is preferable to avoid it. In a batch system, reaction reagents such as carbon tetrachloride, halogen, vinyl chloride, iron catalyst, cocatalyst, and solvent may be charged in the initial stage of the reaction. It is preferable to avoid the method in which the vinyl chloride is fed in liquid by the sequential addition method because the production amount of higher-order vinyl chloride polymer tends to increase. The method for allowing halogen to be present in the reaction system in the method of the present invention is not particularly limited. For example, the halogen may be introduced directly into the reactor alone as a gas or liquid, may be introduced dissolved in carbon tetrachloride or an aprotic polar organic solvent or other solvent, A mixture may be introduced. Among these, when adopting a method of continuously introducing vinyl chloride into the reactor, it is preferable to supply halogen together with vinyl chloride.
[0020]
If the iron catalyst has a relatively small shape, it may be floated or flown in the system by stirring together with the reaction solution, but it is also preferable to fix the iron catalyst and flow only other reaction reagents. . Regardless of which reaction mode is used, since the contact between gas and liquid is an important process in this reaction, it is preferable that the reaction system is equipped with a known device or apparatus for achieving such contact. Examples of such an apparatus include a stirrer and a sparger, but various known apparatuses may be applied.
[0021]
In the case of stirring in this reaction, the range of 10 to 1000 rpm is preferable so that iron and introduced vinyl chloride are quickly diffused into the reaction solution.
[0022]
The material of the reactor which is a sealed container for carrying out the present invention is a material made of glass or resin, or a material lined with glass or resin. The resin used in these is preferably a fluororesin, for example, polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polyperfluoroalkyl vinyl ether, polyhexafluoropropylene, tetrafluoroethylene-perfluoroethylene. A fluoroalkyl vinyl ether copolymer, a tetrafluoroethylene-ethylene copolymer, a hexafluoroethylene-tetrafluoroethylene copolymer, and the like can be mentioned. Of course, any resin that is inert in the reaction system of the present invention is used. be able to.
[0023]
The 1,1,1,3,3-pentachloropropane produced by the method of the present invention is taken out of the reactor and then subjected to an operation for removing the catalyst, metal compound, etc., and an operation for removing the solvent and unreacted raw materials. Further, by rectification, 1,1,1,3,3-pentachloropropane with high purity can be obtained.
[0024]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples. In the examples, the pressure is expressed as a gauge pressure.
[0025]
[Comparative Example 1]
A 1000 ml glass autoclave equipped with a stirrer was charged with 3.0 mol of carbon tetrachloride, 3.0 mol of acetonitrile, and 0.025 mol of ferric chloride, and the air in the reactor was replaced with nitrogen gas and sealed. And heated to 120 ° C. with stirring at 250 rpm. At this time, 0.075 mol of powdered reduced iron was charged, and 2.1 mol of vinyl chloride was further injected to make the pressure almost 0.4 MPa (4 kg / cm ² ), and the reaction was started, and the reaction was continued for 30 minutes. .
[0026]
After the completion of the reaction, the reactor was allowed to cool, the contents were taken out and the metal salt was removed, and this was analyzed by gas chromatography.
[0027]
The yield to 1,1,1,3,3-hexachloropropane, which was the target product, for the charged carbon tetrachloride was 28.5%. The remaining carbon tetrachloride was 1.84 mol (61.3% based on the charged amount).
[0028]
[Comparative Examples 2 and 3]
The reaction was carried out in the same manner as in Comparative Example 1 except that the reaction temperature was 100 ° C. [Comparative Example 2] and 110 ° C. [Comparative Example 3], respectively. After the completion of the reaction, the reactor was allowed to cool, the contents were taken out and the metal salt was removed, and this was analyzed by gas chromatography.
[0029]
The yields to 1,1,1,3,3-hexachloropropane, which was the target product, for the charged carbon tetrachloride were 17.0% and 21.0%, respectively. The remaining carbon tetrachloride was 2.27 mol (75.7% with respect to the charged amount) and 2.13 mol (70.8% with respect to the charged amount), respectively.
[0030]
[Example 1]
A 1000 ml glass autoclave equipped with a stirrer was charged with 3.0 mol of carbon tetrachloride dissolved with 1 mol% of chlorine, 3.0 mol of acetonitrile, and 0.025 mol of ferric chloride, and the air in the reactor was charged with nitrogen. After replacing with gas, it was sealed and heated to 120 ° C. while stirring at 250 rpm. At this time, 0.075 mol of powdered reduced iron was charged, and 2.1 mol of vinyl chloride was further injected to make the pressure almost 0.4 MPa (4 kg / cm ² ), and the reaction was started, and the reaction was continued for 30 minutes. .
[0031]
After the completion of the reaction, the reactor was allowed to cool, the contents were taken out and the metal salt was removed, and this was analyzed by gas chromatography.
[0032]
The yield to 1,1,1,3,3-hexachloropropane, which was the target product, for the charged carbon tetrachloride was 33.0%. The remaining carbon tetrachloride was 1.85 mol (61.7% with respect to the charged amount).
[0033]
[Examples 2 and 3]
The reaction was carried out in the same manner as in Example 1 except that the reaction temperature was 100 ° C. [Example 2] and 110 ° C. [Example 3], respectively. After the completion of the reaction, the reactor was allowed to cool, the contents were taken out and the metal salt was removed, and this was analyzed by gas chromatography.
[0034]
The yields to 1,1,1,3,3-hexachloropropane, which was the target product, for the charged carbon tetrachloride were 19.7% and 27.5%, respectively. The remaining carbon tetrachloride was 2.30 mol (76.5% with respect to the charged amount) and 2.15 mol (71.7% with respect to the charged amount), respectively.
[0035]
【The invention's effect】
As is clear from the results of the examples, the method of the present invention is a method in which halogen is introduced into a reaction system when 1,1,1,3,3-hexachloropropane is produced from vinyl chloride and carbon tetrachloride. Since the reactivity can be increased and the amount of by-products generated can be reduced, this is an industrially advantageous production method.

Claims (5)

1,1,1,3,3 characterized by reacting carbon tetrachloride and vinyl chloride with halogen (halogen means chlorine, bromine or iodine), an iron catalyst and an aprotic organic solvent. -Process for producing pentachloropropane. 2. The method according to claim 1, wherein the halogen is chlorine. 3. The production according to claim 1, wherein at least one compound selected from the group VIII or IB metal halides of the periodic table of elements is added as a promoter to the iron catalyst. Method. The production method according to any one of claims 1 to 3, wherein the aprotic organic solvent is at least one compound selected from nitriles or amides. The method according to any one of claims 1 to 4, wherein the iron catalyst is elemental iron.