JP3059018B2 - Method for producing 2,2-bis (3-nitro-4-hydroxyphenyl) hexafluoropropane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an intermediate between 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane which is a compound useful as a raw material for heat-resistant polymers and various fluorine-containing compounds. 2,2 useful as a body
-Bis (3-nitro-4-hydroxyphenyl) hexafluoropropane.

[0002]

2. Description of the Related Art As a method for producing 2,2-bis (3-nitro-4-hydroxyphenyl) hexafluoropropane, JP-A-59-109546 discloses 2,2-bis (4-hydroxyphenyl) hexafluoropropane. A method for producing 2,2-bis (3-nitro-4-hydroxyphenyl) hexafluoropropane by reacting (hydroxyphenyl) hexafluoropropane with potassium nitrate in trifluoroacetic acid is described. Polymer Science, Pol
ymer Chem. Ed. 20, 2381 (19
No. 82) describes a method in which 2,2-bis (4-hydroxyphenyl) hexafluoropropane is converted into a triflate with trifluoromethanesulfonic anhydride and then nitrated with a mixed acid. It has the drawback that it requires purification using difficult solvents or reagents and difficult distillation.

[0003] Further, German Patent No. 3624815 describes a method for producing crude 2,2-bis (3-nitro-4-hydroxyphenyl) hexafluoropropane by nitrating with nitric acid in a chloroform solvent. However, in this case, a trinitro compound with further progress of nitration is formed, and this trinitro compound is mixed with 2,2-bis (3-nitro-4-hydroxyphenyl) hexafluoropropane, which is a target substance, so that the purity is high. The dinitro form cannot be easily obtained.

[0004] The method described in Japanese Patent Application Laid-Open No. 1-301653, which has been made to solve these problems, is characterized in that a nitration reaction is carried out with nitric acid in a lower fatty acid solvent, and as a result, the dinitro- Crystals of the compound are precipitated from the reaction solution, and a high-purity dinitro compound can be easily obtained in a high yield. According to this method, the dinitro compound precipitates as a crystal from the reaction solution, so that the dinitro compound can be easily obtained by filtration or the like. However, the 2,2-bis (3-nitro- The solid of 4-hydroxyphenyl) hexafluoropropane incorporates the lower fatty acid used as the reaction solvent, and has the drawback that multiple washing with water is required to remove the lower fatty acid. In addition, a remarkable brown coloring which may be caused by the residual nitrate is generated. When this 2,2-bis (3-nitro-4-hydroxyphenyl) hexafluoropropane is reduced to produce 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane, the product contains Again, remarkable coloring is observed, and a problem arises in that recrystallization must be repeated to remove the coloring.

[0005]

Means for Solving the Problems The present inventors have studied to solve the problems of the conventional method, and as a result, have found that the desired product can be obtained in a specific solvent with high yield. The present invention has been reached.

That is, the present invention relates to a method for producing 2,2-bis (3-nitro-4-hydroxyphenyl) hexafluoropropane by nitrating 2,2-bis (4-hydroxyphenyl) hexafluoropropane,
2, wherein alcohols are used as the solvent.
This is a method for producing 2-bis (3-nitro-4-hydroxyphenyl) hexafluoropropane.

The alcohols which can be used in the present invention are aliphatic alcohols having 1 to 4 carbon atoms, such as methanol, ethanol, propanol, isopropanol, and n-alkanol. Preferred are butanol sec-butanol, t-butanol, trifluoroethanol and hexafluoroisopropanol. These alcohols dissolve 2,2-bis (4-hydroxyphenyl) hexafluoropropane as a raw material and a mononitro compound which is an intermediate for nitration well, while a dinitro compound which is a target substance hardly dissolves. Thus, the resulting dinitro compound can be obtained as high-purity crystals. The amount of alcohol used in the reaction is 0.1 to 2.0 K of 2,2-bis (4-hydroxyphenyl) hexafluoropropane as a raw material per liter of alcohol.
g is preferred. If it is 0.1 kg or less, the productivity is low, and if it is 2.0 kg or more, a complete homogeneous phase may not be obtained, which is not preferable. The nitric acid used as the nitrating agent used in the reaction may be fuming nitric acid, concentrated nitric acid, or dilute nitric acid which is industrially used.

When water is present in the reaction system, the solubility of the dinitro compound is further reduced, and crystals can be obtained in good yield.
If the amount of water exceeds 50% based on the alcohols used, the mononitro compound is undesirably precipitated together with the dinitro compound as an oil. Further, since the nitration reaction is a reaction for producing water, the amount of water increases as the reaction proceeds. Therefore, it is preferable to select the concentration of nitric acid to be used in consideration of the amount of water generated by the nitration reaction, and to carry out the reaction so that the purity and the yield are the highest. The amount of nitric acid used is 2 to 2 based on the raw material 2,2-bis (4-hydroxyphenyl) hexafluoropropane.
It is preferably 5 equivalents, and in order to obtain the desired dinitro compound in good yield and high purity, it is preferable to use nitric acid at a concentration of 60 to 70% in consideration of the amount of water present in the reaction system. The reaction temperature depends on the boiling point of the alcohol used.
0-100 ° C is preferred. The reaction pressure is not particularly limited, but is preferably 1 to 10 kg / cm ^{2, and} is usually performed at normal pressure.

Although the nitration reaction proceeds sequentially, in the method of the present invention, the mononitrate is converted into an oily substance, which is smoothly dinitrated without separation, and the desired dinitro compound is precipitated as a crystal, and furthermore, it is contained in the crystal. (Alcohols) and nitrate groups taken into water can be easily removed by washing with water and oven drying, so that high-purity 2,2-bis (3-nitro-4-hydroxyphenyl) hexafluoro Propane can be obtained.

[0010]

The present invention will be described below in detail with reference to examples. The purity analysis of the target product was performed by liquid chromatography.

Example 1 100 ml of methanol and 2,2-bis (4-hydroxyphenyl) were placed in a 200 ml four-necked round bottom flask equipped with a thermometer, a stirrer, a Dimroth condenser, and a 100 ml dropping funnel. ) 67.2 g of hexafluoropropane (0.20 m
ol), stirring was started, and the reaction temperature was raised to 60.
Temperature to 2,2-bis (4-hydroxyphenyl)
After hexafluoropropane is completely dissolved, 60
% Nitric acid was dropped from a dropping funnel charged with 84.0 g (0.40 mol) of nitric acid. Nitric acid was added dropwise over 1 hour while maintaining the reaction temperature at 60 ° C. When the nitric acid was dropped, yellow crystals began to precipitate. After dropping the nitric acid, the reaction temperature was further maintained at 60 ° C., and the reaction was continued for 5 hours. The generated yellow crystals were separated by filtration under reduced pressure, washed with 100 ml of water and dried in an oven to give a purity of 99.1%.
As a result, 74.7 g of 2,2-bis (3-nitro-4-hydroxyphenyl) hexafluoropropane as yellow crystals of (trinitro compound 0.8%) was obtained. The yield at this time is 8
It was 6.9%.

The 2,2-bis (3-nitro-4-hydroxyphenyl) hexafluoropropane obtained here is treated with 5% -Pd / C as a catalyst in a methanol solvent and a hydrogen pressure of 5 kg / cm ² , A direct reduction reaction was performed at a reaction temperature of 100 ° C. for 6 hours to obtain 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane. The conversion of this reduction reaction is 99% or more and 2,2-bis (3-amino-4
-Hydroxyphenyl) hexafluoropropane had a purity of 97.2%. After filtering to remove the catalyst, the mixture was poured into water to precipitate 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane crystals, which were collected by filtration. The crystals recovered here were black-gray crystals and had an APHA color of 180. Ethyl acetate
One recrystallization of n-hexane system, purity 99.6%, A
Crystals having a PHA color of 100 were obtained.

Example 2 In Example 1, isopropanol was used in place of methanol, the reaction temperature was 70 ° C., and the reaction time after dropping nitric acid was 3 hours.
Except for the time, the purity was 99.0% in the same manner as in Example 1.
72.1 g (yield 84.6%) of 2,2-bis (3-nitro-4-hydroxyphenyl) hexafluoropropane as yellow crystals of (trinitro compound 0.6%) was obtained.

The 2,2-bis (3-nitro-4) obtained here
-Hydroxyphenyl) hexafluoropropane was subjected to a reduction reaction in the same manner as in Example 1, and the purity was 96.9%.
Crystals of 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane A color 160 were obtained. The recrystallization was performed once in the same manner as in Example 1 to obtain 2,2-bis (3) of APHA color 80 with a purity of 99.7%.
-Amino-4-hydroxyphenyl) hexafluoropropane was obtained.

Example 3 The procedure of Example 1 was repeated, except that trifluoroethanol was used instead of methanol, and that the reaction time after the addition of nitric acid was changed to 4 hours. (Trinitro body
0.8%) of yellow crystalline 2,2-bis (3-nitro-
4-hydroxyphenyl) hexafluoropropane 7
2.1 g (82.6% yield) was obtained.

The 2,2-bis (3-nitro-4) obtained here
-Hydroxyphenyl) hexafluoropropane was subjected to a reduction reaction in the same manner as in Example 1, and the purity was 97.1%.
A color 200 crystals of 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane were obtained. In addition, recrystallization was performed once in the same manner as in Example 1 to obtain 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane having an APHA color of 100 and a purity of 99.6%.

Comparative Example 1 100 ml of chloroform and 2,2-bis (4-hydroxyphenyl) were placed in a 200 ml four-necked round bottom flask equipped with a thermometer, a stirrer, a Dimroth condenser, and a 100 ml dropping funnel. 67.2 g of hexafluoropropane (0.2
0 mol), stirring was started, and the reaction temperature was raised to 60 ° C. After 2,2-bis (4-hydroxyphenyl) hexafluoropropane was completely dissolved, 84.0 g of 60% nitric acid (0%) was dissolved in advance. .40 mol) was started to drop nitric acid from the dropping funnel charged. Nitric acid was added dropwise over 1 hour while maintaining the reaction temperature at 60 ° C.
After the addition of nitric acid, the reaction temperature was further maintained at 60 ° C., and the reaction was continued for 2 hours. At this time, the purity of 2,2-bis (3-nitro-4-hydroxyphenyl) hexafluoropropane is 8
At 1.9%, a 8.4% trinitro compound was produced. 2 more
When the reaction was continued for 1 hour, the trinitro compound was 17.6%
And the purity of 2,2-bis (3-nitro-4-hydroxyphenyl) hexafluoropropane is also 71.0%.
Has dropped.

Comparative Example 2 50 ml of acetic acid and 2,2-bis (4-hydroxyphenyl) were placed in a 200 ml four-necked round bottom flask equipped with a thermometer, a stirrer, a Dimroth condenser, and a 100 ml dropping funnel.
67.2 g (0.20 mol) of hexafluoropropane
Was added, stirring was started, and the reaction temperature was raised to 50 ° C., and after 2,2-bis (4-hydroxyphenyl) hexafluoropropane was completely dissolved, 96.6 g (0.46 mol) of 60% nitric acid was previously dissolved. ) Was started to drop nitric acid from the dropping funnel charged. Nitric acid is dropped at a reaction temperature of 50.
The whole amount was added dropwise over 1 hour while maintaining the temperature. Crystals started to precipitate when about 2/3 of the predetermined amount of nitric acid was dropped. After the addition of nitric acid, the reaction temperature was further maintained at 50 ° C., and the reaction was continued for 1 hour. Then, 27 ml of water was added to completely precipitate crystals.
The generated yellow crystals were separated by filtration under reduced pressure, washed with 50 ml of 50% methanol water, washed with water and dried in an oven. The color changed from yellow crystals to brown crystals. At this time, the purity of 2,2-bis (3-nitro-4-hydroxyphenyl) hexafluoropropane is 97.
At 3%, the trinitro form was contained at 1.2%. The yield was 71.6 g, and the yield was 83.3%.

The 2,2-bis (3-nitro-4-hydroxyphenyl) hexafluoropropane obtained here was reacted with 5% -Pd / C as a catalyst in a methanol solvent under a hydrogen pressure of 5 kg / cm ^{2 at} a hydrogen pressure of 5 kg / cm ² . A direct reduction reaction was performed at a temperature of 100 ° C. for 6 hours to obtain 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane. The conversion of this reduction reaction is 99% or more and 2,2-bis (3-amino-4-
The purity of (hydroxyphenyl) hexafluoropropane was 94.0%. From this, the catalyst is removed by filtration, and then poured into water to give 2,2-bis (3-amino-4.
-Hydroxyphenyl) hexafluoropropane was precipitated and collected by filtration. The crystals collected here were black-gray crystals, and the APHA color (5% methanol solution) was measured. This was recrystallized three times with an ethyl acetate-n-hexane system to give a purity of 9
9.9%, APHA color was 100.

[0020]

EFFECTS OF THE INVENTION 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane, a compound useful as a raw material for heat-resistant polymers, and 2,2 useful as an intermediate of various fluorine-containing compounds -Bis (3-nitro-4-hydroxyphenyl) hexafluoropropane can be obtained with high purity.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-1-301563 (JP, A) JP-A-63-305130 (JP, A) JP-A-63-33353 (JP, A) JP-A-63-33353 201149 (JP, A) JP-A-59-109546 (JP, A) JP-A-56-169650 (JP, A) JP-A-1-165552 (JP, A) U.S. Patent 5,262,056 (US, A) U.S. Pat. (US, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C07C 205/21 C07C 201/08 CA (STN) REGISTRY (STN)

Claims (1)

(57) [Claims] (1) 2,2-bis (4-hydroxyphenyl)
A method for producing 2,2-bis (3-nitro-4-hydroxyphenyl) hexafluoropropane by nitrating hexafluoropropane, wherein alcohols are used as a solvent, wherein 2,2-bis ( Production method of (3-nitro-4-hydroxyphenyl) hexafluoropropane.