JPH0717544B2 - Method for producing aryl ethylene - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing highly pure arylethylene economically and on an industrial scale. More specifically, the present invention relates to a method for producing high-purity arylethylene, which comprises a step of decomposing diarylethane, a step of separating a decomposition product, and a step of hydrogenating the recovered diarylethane.

[Prior Art and Problems to be Solved by the Invention] Conventionally, various methods have been proposed for the method for producing arylethylene by decomposing 1,1-diarylethane in the presence of an acid catalyst. There is.

Industral and Engineering Chemistry, Vol.46, No.4,652 (1954) Journal of Chemical and Engineering Data, Vol.9, No.1,104 (1964) I & EC Product Research and Development, Vol.3, No.1,16 ( 1964) The above-mentioned document describes the decomposition of 1,1-ditolylethane and 1,1-dixylethane to give methylstyrene and dimethylstyrene, respectively, and ethyl styrene, isopropyl styrene, t-butyl styrene, etc. It has been described.

Further specific disclosed techniques include, for example, U.S. Pat.No. 2,420,689, a method for obtaining dimethylstyrene by decomposing dixylylethane in the presence of a kaolin catalyst, and U.S. Pat.No. 2,422,318, asymmetric diarylethane decomposition. Method, U.S. Pat.No. 2,864,872, a method of using silica as a decomposition catalyst, U.S. Pat.No. 2,954,413, a method of decomposing dixylylethane using a fluid catalyst, U.S. Pat.No. 3,025,330, ditolylethane. Method for obtaining methylstyrene from U.S. Pat. No. 2,976,333 and U.S. Pat. No. 2,976,334
The publication discloses a method of improving a decomposition catalyst and the like.

In the method of decomposing 1,1-diarylethane, not all 1,1-diarylethane is decomposed and converted into arylethylene and mono- or polyalkylbenzene, and the raw material 1,1-diarylethane is unreacted. It is unavoidable that it is contained in the reaction mixture as it is. This is also clear from the method disclosed in the above publication and proposed, in that the purpose of the reaction is 40% to 60%. In other words, 60 to 40% of unreacted raw material is produced.

Therefore, in order to economically produce arylethylene by decomposing 1,1-diarylethane, unreacted 1,1-
The re-use and re-decomposition of diarylethane becomes a prerequisite. That is, 1,1 separated from the reaction mixture
-When re-decomposing and reusing a fraction mainly containing diarylethane, whether or not arylethylene having a purity and properties suitable for the intended purpose can be obtained, and whether or not the decomposition reaction can be industrially applied Can also be said to have decided.

By the way, arylethylenes obtained by decomposing these 1,1-diarylethanes are, for example, disclosed in West German Published Patent No. 2325302 and British Patent No. 1,565,2.
As proposed in Japanese Patent Publication No. 35, etc., as an industrially useful intermediate, and in Ind.Eng.Chem., Vol.46,652 (1954), as a raw material for polymer synthesis with high weather resistance, There is a useful application, and therefore a method for economically producing aryl ethylene has been desired.

The inventors of the present invention also conducted a study for industrially and economically carrying out the decomposition reaction of 1,1-diarylethane, and found that the fraction mainly containing unreacted 1,1-diarylethane was simply re-decomposed as it was. Therefore, the present invention has been completed by finding that the property of arylethylene obtained as a result of the decomposition is unfavorable in addition to the fact that the decomposition catalyst is deteriorated with time.

That is, the present inventors decomposed 1,1-diarylethane, as a result, in the decomposition product, an olefin having a boiling point close to that of 1,1-diarylethane and difficult to decompose is produced, which is unreacted. It has been found that it is inevitable to mix in a fraction mainly containing 1,1-diarylethane. Moreover, if this is directly returned to the cracking step for cracking, olefin is mixed in the cracking raw material, and therefore the cracked product obtained by cracking must be complicated. The boiling point of this by-product at the time of re-decomposition is also close to that of the target arylethylene, and as a result, a vicious cycle occurs in which it is unavoidable that the by-product is mixed in the target arylethylene fraction. There was found.
Therefore, a large amount of unreacted 1,1-diarylethane raw material fraction cannot be simply recycled, and therefore 1,
The conventional method of decomposing 1-diarylethane to produce arylethylene has not been an economical method from an industrial viewpoint.

[Means for Solving the Problems] In view of the above-mentioned circumstances, the present invention provides a method for producing arylethylene comprising the following steps.

Step (I): contacting the 1,1-diarylethane represented by the general formula (A) with an acid catalyst in the presence of an inert gas,
A step of decomposing into arylethylene represented by the general formula (B) and / or the general formula (C) and an alkylbenzene represented by the general formula (D) and / or the general formula (E), step (II): the above decomposition From the reaction mixture obtained in step (I), a fraction mainly containing 1,1-diarylethane represented by general formula (A) and an aryl represented by general formula (B) and / or general formula (C) Fraction containing mainly ethylene and general formula (D) and / or general formula (E)
A step of separating into a fraction mainly containing an alkylbenzene represented by: Step (III): a fraction mainly containing 1,1-diarylethane represented by the general formula (A), obtained in the above separation step (II) Is subjected to a hydrogenation treatment by bringing it into contact with a hydrogenation catalyst in the presence of hydrogen, and step (IV): the hydrogenation-treated fraction obtained in the hydrogenation treatment step (III) is decomposed by the decomposition step (I). ) And re-decompose.

Formula _{(A) Ar 1 -CH (CH} 3) -Ar 2 formula _{(B) Ar 1 -CH = CH} 2 Formula _{(C) Ar 2 -CH = CH} 2 Formula (D) Ar ₁ -H General Formula (E) Ar ₂ —H In the above general formulas (A), (B), (C), (D) and (E), Ar ₁ and Ar ₂ are each a hydrogen atom or one having 4 or less carbon atoms or A phenyl group or an alkylphenyl group having a plurality of identical or different alkyl groups, wherein the total number of carbon atoms of the alkyl groups is 4 or less,
Ar ₁ and Ar ₂ may be the same or different.

That is, the present invention provides a method for producing arylethylene, which comprises the above-mentioned step (I), step (II), step (III) and step (IV), and decomposes 1,1-diarylethane. Provides a method for industrially and economically producing highly pure arylethylene.

Further, the present invention will be described in detail.

Step (I) in the method of the present invention is a step in which 1,1-diarylethane is contacted with an acid catalyst in the presence of an inert gas to decompose arylethylene and alkylbenzene. For the decomposition step (I), a method conventionally proposed can be applied.

1,1-diarylethane has a hydrogen atom or an alkyl group having 4 or less carbon atoms at the same carbon atom of ethane,
A phenyl group or an alkylphenyl group in which the total number of carbon atoms in the alkyl group is 4 or less is substituted. These groups may be the same or different. Further, when a plurality of alkyl groups are substituted, the alkyl groups may be the same or different.

As the raw material 1,1-diarylethane, any one produced by a known method can be used. Specific examples of the method for producing 1,1-diarylethane include, for example, a method of reacting polyalkylbenzene with acetaldehyde or acetylene in the presence of sulfuric acid, polyalkylbenzene and 1,1 in the presence of Friedel-Crafts catalyst such as aluminum chloride. There are a method of reacting with 1-dichloroethane and a method of reacting polyalkylbenzene with alkylstyrene using an acid catalyst. In addition to 1,1-diarylethane produced by the reaction, for example, diphenylethane and ethylenediphenyl contained in the heavy by-product oil fraction produced as a by-product during the production of ethylbenzene for the production of styrene. Fractions mainly containing ethane can also be used.

Specific examples of 1,1-diarylethane and symmetrical compounds that can be used in the method of the present invention include 1,1-diphenylethane, 1,1-ditolylethane, 1,1-dixylylethane, 1,1- Di (ethylphenyl) ethane, 1,1-di (trimethylphenyl) ethane, 1,1-di (methylethylphenyl) ethane, 1,1-di (propylphenyl) ethane, 1,1-di (tetramethylphenyl) ) Ethane, 1,1-
Examples include di (dimethylethylphenyl) ethane, 1,1-di (methylpropylphenyl) ethane, 1,1-di (diethylphenyl) ethane, 1,1-di (butylphenyl) ethane.

In step (I) of the method of the present invention, it is suitable that an inert gas is allowed to coexist and is brought into contact with an acid catalyst in a diluted state. As the inert gas, in addition to inorganic gases such as hydrogen, helium, argon, nitrogen, steam, etc., hydrocarbons such as methane, ethane, propane and the like can be used as long as they do not inhibit the acid activity of the acid catalyst. Can also be used. The inert gas may be used alone or in an appropriate mixture. Industrially, water vapor is a preferable gas for handling as the inert gas. The dilution with an inert gas is preferably such that the molar ratio represented by (inert gas / 1,1-diarylethane) is 50 or more. There is no particular upper limit to the number of moles for dilution, and the more preferable it is to dilute, the more practically the upper limit is 500.

The acid catalyst to be contacted is a protic acid, a solid acid, or a protic acid-supported solid acid. As the protic acid, phosphoric acid,
It is an inorganic protonic acid such as sulfuric acid, hydrochloric acid, and heteropolyacid such as silicotungstic acid and phosphotungstic acid, and an organic protonic acid such as benzenesulfonic acid and toluenesulfonic acid. As the solid acid, silica alumina, silica magnesia, synthetic solid acid catalyst such as zeolite, activated clay,
In addition to natural solid acid substances such as acid clay, kaolin, and attapulgite, a proton acid-supporting solid acid catalyst obtained by impregnating and supporting the above-mentioned protonic acid on an inorganic porous carrier having no acid activity such as silica and alumina may be used.

The temperature of contact with the acid catalyst can be appropriately selected depending on the type of the acid catalyst, but is in the range of 200 ° C to 650 ° C. A temperature of 200 ° C to 350 ° C is preferable for contact with a protic acid, and a temperature of 300 ° C to 600 ° C is preferable for contact with a solid acid.

In the decomposition of step (I) of the present invention, the 1,1-diarylethane is decomposed by contacting it with an acid catalyst under the above-mentioned dilution conditions and temperature conditions. The decomposition method can be appropriately selected according to the type of the acid catalyst, but gas-phase contact with a solid acid catalyst or a proton acid-supporting solid acid catalyst is preferable in consideration of corrosion and continuation of the apparatus. Gas phase contact is 1,
Atmospheric pressure, elevated pressure, or reduced pressure may be used as long as the gas phase is maintained under the condition in which 1-diarylethane is diluted. Further, as the reaction mode, any of a fixed bed, a moving bed and a fluidized bed may be used.

The decomposition reaction of step (I) is represented by a chemical formula as follows.

Ar ₁ -CH (CH ₃ ) -Ar _{2 When} decomposed on the right side: → Ar ₁ -CH = CH ₂ + H-Ar _{2 When} decomposed on the left side → → Ar ₁ -H + CH ₂ = CH-Ar ₂ 1,1-diarylethane, namely Ar ₁ and Ar ₂
And are the same, a single aryl ethylene (Ar--CH
═CH ₂ ) and a single alkylbenzene (Ar—H) are obtained, and therefore it is often industrially preferable to use symmetrical 1,1-diarylethane as a decomposition raw material.

The step (II) in the method of the present invention mainly contains a fraction mainly containing 1,1-diarylethane, a fraction mainly containing arylethylene, and an alkylbenzene mainly from the reaction mixture obtained in the decomposition step (I). This is a step of separating into fractions.

In the decomposition step (I), all 1,1-diarylethane is not decomposed, and unreacted 1,1-
Diarylethane remains. In the step (II), it is important to separate the target product, arylethylene, into a purity suitable for the intended use. At the same time, it is also important in industrial practice to separate unreacted 1,1-diarylethane so that it can be decomposed again.

That is, in the separation step (II), Ar ₁ -H of the general formula (D) and / or Ar ₂ -H of the general formula (E) produced by the decomposition is used.
And an objective product of Ar ₁ —CH═CH ₂ of the general formula (B) and / or Ar _{2 of the} general formula (C).
An aryl styrene fraction with —CH = CH ₂ and an Ar ₁ —CH (CH ₃ ) —Ar ₂ fraction of the general formula (A), which is a raw material fraction to be recovered and reused as an unreacted material. This is the step of separating.

As a method for separation, any of conventionally known physical means and chemical means can be selected. For example, as the physical means, solvent extraction separation means utilizing the difference in solubility or partition coefficient in the solvent, adsorption separation means utilizing the difference in adsorptivity, crystallization separation means utilizing the difference in melting point or freezing point, boiling point Distillation and separation means utilizing the difference can be applied.

Of these means, the distillation separation means, particularly the vacuum distillation means, is a practically preferable separation means from the viewpoint of easy operation. The alkylbenzene, arylethylene and 1,1-diarylethane in the reaction mixture obtained in step (I) of the present invention can be easily separated by a conventional distillation means. In the distillation operation, vacuum distillation, which operates under reduced pressure, is preferable because the target product is arylethylene, which is easily thermally polymerized.

However, in the case of an arylethylene having an alkyl group having 5 or more carbon atoms or an arylethylene having an alkyl group having a total carbon number of 5 or more, the boiling point is high even if the distillation pressure is lowered, and the thermal polymerization results. Loss increases. That is, such higher alkyl styrene is not preferable because an advantageous distillation separation means cannot be used.

The present inventors have found that when the separated fraction mainly containing unreacted 1,1-diarylethane is decomposed as it is in step (I), the decomposition catalyst is rapidly deteriorated with time, and The inventors have found that the properties of the thus-obtained arylethylene are unfavorable in practical use, and have completed the present invention.

That is, in the decomposition step in the step (I), the ethane moiety of the 1,1-diarylethane having two aryl groups attached to the same carbon undergoes dehydrogenation by a decomposition catalyst and is represented by the following formula. As shown, it became clear that it was inevitable that it would be converted to an olefin and diarylethylene would be produced as a by-product.

_{Ar-CH (CH 3) -Ar} → Ar-C (= CH 2) -Ar Furthermore, since diaryl ethylene by-product described above are close boiling point, conventional separation, for example distillation separating means, in fact It is impossible to separate from the unreacted 1,1-diarylethane above. However, as described above, when the fraction mainly containing 1,1-diarylethane recovered in the separation step (II) is used as it is as the decomposition raw material in the decomposition step (I), the obtained target product is obtained. The property of barrel arylethylene is not suitable for the purpose of use.

As a result of repeated studies for further reuse of such recovered 1,1-diarylethane fraction, the present inventors have confirmed that diarylethylene contained in this fraction is 1,2
It has been found that by converting to 1-diarylethane, the decomposition catalyst can be reused as a decomposition raw material in the step (I) without any trouble without causing deterioration with time.

The step (III) in the method of the present invention comprises a separation step (II)
The fraction mainly containing 1,1-diarylethane obtained in step (1) is subjected to hydrogenation treatment by contacting it with a hydrogenation catalyst in the presence of hydrogen, and diarylethylene produced as a by-product in step (II) is hydrogenated at the olefin part. This is the process of adding paraffin. Here, it is important to select the conditions under which the aromatic ring present in the 1,1-diarylethane is not hydrogenated to become a cyclohexyl ring.

Therefore, the hydrogenation catalyst is appropriately selected from known hydrogenation catalysts as long as it is a hydrogenation catalyst that hydrogenates an ethylenic carbon-carbon unsaturated double bond and is inert to nuclear hydrogenation of an aromatic ring. You can choose to. Specific examples include metal catalysts containing Pd, Rh, Pt, and Ni-based metals. These metal catalysts can be used by supporting them on an appropriate carrier such as silica, silica-alumina or carbon. The hydrogenation reaction condition may be any condition that does not hydrogenate the aromatic ring, and various by-products are by-produced, so as an index of the degree of hydrogenation, the bromine number is 1.0 or less, preferably 0.5 or less. Thus, hydrogenation may be performed. The hydrogenation temperature is preferably from room temperature to 300 ° C., and the reaction pressure is from normal pressure to 300 kg / cm ² .

The arylethylene obtained by returning the fraction mainly containing 1,1-diarylethane obtained by the hydrogenation treatment of step (III) to step (I) and then re-decomposing it is sufficient for the purpose of using it. It is a satisfactory property.

The treatment of the step (III) may be performed on the fraction obtained mainly in the 1,1-diarylethane obtained in the step (II) alone. In addition, new 1,1 to supply to process (I)
-After mixing the diarylethane with the fraction mainly containing 1,1-diarylethane obtained in step (II),
You may perform the process of process (III). Whatever it is,
The distillate obtained by hydrogenation is returned to the decomposition step of the above step (I) and again decomposed in the same manner, and the obtained reaction product becomes the same.

The method of the present invention can be performed in each step or continuously as a whole. Further, any or all of the steps can be performed in a batch system.

[Effects of the Invention] In the method of the present invention, 1,1-diarylethane is decomposed to produce high-purity arylethylene, and the decomposition catalyst does not change with time. Therefore, the unreacted raw materials can be reused, and as a result it is possible to carry out the process industrially and economically.

For example, since the arylethylene produced by the present invention has a high purity, it can be suitably used as a monomer for radical polymerization or copolymerization, and further, in the presence of a transition metal complex catalyst, budroformylation reaction, hydroesterification reaction, etc. It can also be suitably used as a raw material.

The present invention will be further described below with reference to examples. Example 1:
Synthesis of styrene by decomposing 1,1-diphenylethane Step (I): Decomposition reaction A silica-alumina catalyst N-631-L (trade name) manufactured by JGC Chemical Co., Ltd. having a mesh size of 15 to 25 mesh is manufactured from stainless steel with an inner diameter of 12 mm. The reaction tube was filled to a height of 135 mm. This was heated to a temperature of 500 ° C. in an electric furnace, and 1,1-diphenylethane having a bromine number of 0.020 was continuously fed at 15 ml / hr and water was continuously fed at 150 ml / hr for decomposition. After cooling the reactor outlet, the oil layer was separated and analyzed by gas chromatogram. The analysis results are shown below.

Gas chromatogram analysis results-1 Light fraction 1.9% by weight Benzene fraction 18.8% by weight Ethylbenzene fraction 1.5% by weight Styrene fraction 23.0% by weight Unreacted 1,1-diphenylethane fraction 53.9% by weight Heavy fraction 0.9% by weight Average decomposition rate 45.6% Step (II): Decomposition The decomposition product obtained in the decomposition step (I) was subjected to precision distillation under normal distillation conditions (the same applies to the following distillation), and 30 mmHg
Styrene fraction (recovery rate 85%) in the distillation temperature range 54 ℃ to 58 ℃ under a reduced pressure of 〜35mmHg (fractions mainly composed of styrene, the same applies below) and unreacted in the distillation temperature range 148 ℃ to 155 ℃ A 1,1-diphenylethane recovery fraction (recovery rate 93%) was obtained.

The bromine number of the recovered 1,1-diphenylethane fraction is 2.37.
According to mass spectrometry, the content of the component having m / e = 180 (m / e of 1,1-diphenylethane = 182) was 2.5%.

Step (III): Hydrogenation treatment Palladium catalyst G-68B (trade name) manufactured by Nissan Gardler Co., Ltd. having a size of 20 to 25 mesh was filled in a stainless steel reaction tube having an inner diameter of 10 mm at a height of 80 mm. This was heated to 18
The mixture was heated to 0 ° C., and the 1,1-diphenylethane fraction obtained in the separation step (II) was supplied at 10 ml / hr and 200 ml / hr of hydrogen for hydrogenation treatment. This hydrogenation treatment has a pressure of 12 kg / cm ²
I did it in.

The bromine number of the treated 1,1-diphenylethane fraction is 0.17.
And the content of the component of m / e = 180 by mass spectrometry is 0.5
% Or less.

Example 2: Decomposition of hydrogen-treated 1,1-diphenylethane fraction The 1,1-diphenylethane fraction hydrogenated in step (III) of Example 1 is treated in the same manner as in step (I) of Example 1. Was decomposed and subjected to precision distillation in the same manner as in the separation step (II) of Example 1 to recover a styrene fraction and a 1,1-diphenylethane fraction. The recovery rate of each fraction was almost the same as in Example 1. The analysis results of the reaction product are shown below.

Gas chromatogram analysis results-2 Light fraction 2.1% by weight Benzene fraction 19.6% by weight Ethylbenzene fraction 1.3% by weight Styrene fraction 21.5% by weight Unreacted 1,1-diphenylethane fraction 54.3% by weight Heavy fraction 1.2% by weight Average decomposition rate 45.0% The bromine number of the recovered 1,1-diphenylethane was 2.54, and the content of the component with m / e = 180 by mass spectrometry was 2.5%.

Comparative Example 1: Re-decomposition of the recovered fraction of 1,1-diphenylethane The 1,1-diphenylethane fraction recovered in the step (II) of Example 1 was used as it is, that is, without hydrogenation treatment, and Example 1 Was decomposed in the same manner as in step (I) of Example 1 and precision distilled in the same manner as in step (II) of Example 1 to obtain a styrene fraction and 1,1-
And diphenylethane fraction were obtained. The recovery rate of each fraction was almost the same as that in the example. The analysis results of the reaction product are shown below.

Gas chromatogram analysis results-3 Light fraction 1.5% by weight Benzene fraction 14.3% by weight Ethylbenzene fraction 1.2% by weight Styrene fraction 16.6% by weight Unreacted 1,1-diphenylethane fraction 65.6% by weight Heavy fraction 0.8% by weight Average decomposition rate 33.9% The bromine number of the recovered 1,1-diphenylethane was 4.22, and the content of the component with m / e = 180 by mass spectrometry was 4.7%.

The changes over time in the decomposition rates of Examples 1 and 2 and Comparative Example 1 are as follows.

(Ratio of Decomposition Rate when Decomposition Rate at Each Elapsed Time in Example 1 is 100) Example 3: Production of Dimethylstyrene by Decomposition of 1,1-Di (orthoxylyl) ethane Orthoxylene and acetaldehyde were prepared. The reaction was carried out with a sulfuric acid catalyst. Distillation temperature at pressure reduction of 3-5 mmHg 146
For 1,1-di (orthoxylyl) ethane fraction (bromine number = 0.27) at .about.151 ° C., the decomposition step (I) was carried out in the same manner as in Example 1.
And separation step (II) was performed. Average decomposition rate is 47.3%
Met.

The decomposition products were subjected to precision distillation to obtain a dimethylstyrene fraction with a distillation temperature of 67 to 70 ° C at a reduced pressure of 10 mmHg to 12 mmHg at a recovery rate of 78%, and a distillation temperature at a reduced pressure of 2 mmHg to 3 mmHg.
The 1,1-di (orthoxylyl) ethane fraction at 9 to 137 ° C was added to 91
Obtained with a% recovery. The bromine number of the recovered 1,1-di (orthoxylyl) ethane fraction is 2.17, and the result of mass spectrometry is
m / e = 236 [m / e of 1,1-di (orthoxylyl) ethane = 23
8] was included at 3.0%.

The recovered 1,1-di (orthoxylyl) ethane was subjected to hydrogenation treatment in the same manner as in step (III) of Example 1 to obtain a treated fraction having a bromine number of 0.21.

Example 4: Manufacture of dimethylstyrene from hydrotreated recovered product The hydrotreated 1,1-diphenylethane fraction obtained in Example 3 was decomposed in the same manner as in the decomposition step (I) of Example 1 ( By precision distillation, a dimethylstyrene fraction and a 1,1-di (orthoxylyl) ethane fraction with a recovery rate of 89% were obtained by precision distillation with an average decomposition rate of 46.9%).

The 1,1-di (orthoxylyl) ethane bromine number recovered is
It is 2.65, and the content of the component of m / e = 236 by mass spectrometry is
It was 3.5%.

Comparative Example 2: Manufacture of dimethylstyrene using an untreated product The 1,1-di (orthoxylyl) ethane fraction recovered by the precision distillation of Example 3 was decomposed as it was in the same manner as in Example 1 (average decomposition rate 32.1%). ) And the decomposition product were similarly finely distilled to obtain a dimethylstyrene fraction and a 1,1-di (orthoxylyl) ethane fraction. The recovery rate of each fraction was almost the same as in Example 3.

The bromine number of the recovered 1,1-di (orthoxylyl) ethane was 4.37, and the content of the component of m / e = 236 by mass spectrometry was 4.5%.

Example 5: Production of t-butylstyrene by decomposing 1,1-di (t-butylphenyl) ethane t-butylbenzene and acetaldehyde were reacted with a sulfuric acid catalyst to obtain distillate under reduced pressure of 2 mmHg to 3 mmHg. 1,1-di (t-butylphenyl) at a temperature of 160 ℃ -166 ℃
For the ethane fraction (bromine number = 0.17, boiling point = 96 ° C. to 97 ° C.), the decomposition step (I) (average decomposition rate is 4
0.8%) and separation step (II).

Precise distillation of the decomposition product, 73% of the t-butylstyrene fraction with a distillation temperature of 79 ℃ to 83 ℃ at a reduced pressure of 6mmHg to 8mmHg
, And a 1,1-di (t-butylphenyl) ethane fraction with a distillation temperature of 159 ° C. to 166 ° C. at a reduced pressure of 2 mmHg to 3 mmHg was obtained with a recovery rate of 92%. Recovered 1,1-di (t-
The bromine number of the butylphenyl) ethane fraction is 2.17, and as a result of mass spectrometry, it contains 4.0% of the component of m / e = 292 [m / e = 294 of 1,1-di (t-butylphenyl) ethane]. It was

The recovered 1,1-di (t-butylphenyl) ethane fraction was hydrogenated in the same manner as in Example 1 to give a bromine number of 0.18.
To obtain a treated fraction of.

Example 6: Production of t-butylstyrene by hydrogenation-treated recovered product The hydrogenation-treated 1,1-di (t-butylphenyl) ethane fraction obtained in Example 5 was subjected to the decomposition step (I ) (Average decomposition rate 38.9%) and precision distillation yielded 74% recovery of t-butylstyrene fraction and recovery rate of 89%.
% 1,1-di (t-butylphenyl) ethane fraction was obtained.

The bromine value of the recovered 1,1-di (t-butylphenyl) ethane was 1.98, and the content of the component with m / e = 292 by mass spectrometry was 3.5%.

Comparative Example 3: Preparation of t-butylstyrene without treatment 1,1-di (t- recovered by precision distillation of Example 5
The butylphenyl) ethane fraction was directly decomposed in the same manner as in Example 1 (average decomposition rate 27.2%), and the decomposition product was similarly finely distilled to obtain t-butylstyrene fraction and 1,1-di (t-
Butylphenyl) ethane fraction was obtained. The recovery rate of each fraction was almost the same as in Example 5.

The bromine number of the recovered 1,1-di (t-butylphenyl) ethane was 3.81, and the content of the component of m / e = 292 by mass spectrometry was 7.5%.

Example 7: Copolymerization with styrenes and production of resin film and comparison of weather resistance Each styrene fraction obtained in each of Examples 1 to 6 and Comparative Examples 1 to 3 was polymerized. Then, a resin film was manufactured and weather resistance was compared.

Di-t- was added to each of the obtained styrene fractions as a polymerization initiator.
Butyl peroxide was added and the mixture was heated to a temperature of 60 ° C. and allowed to stand for 12 hours to obtain a resinous material.

Dissolve the obtained resin in benzene and apply 0.2 mm to the glass plate.
To obtain a resin film coated on a glass plate by drying for 4 hours in a constant temperature bath at a temperature of 65 ° C.

With respect to each styrene fraction, three resin films were irradiated with ultraviolet rays at a temperature of 70 ° C., and the state of change of the resin surface was observed to compare the weather resistance of the resin films. Regarding the change of the surface, coloring of the resin film and cracks on the surface of the resin film were visually observed.

Example 8: Carbonylation Reaction of Styrene Fraction Each of the styrene fractions obtained in Examples 1 to 6 and Comparative Examples 1 to 3 was subjected to a carbonylation reaction.

In a pressure resistant reactor equipped with a stirrer with an internal volume of 250 ml, 30 g of styrene fraction and 40 g of toluene were put, the temperature was kept at 60 ° C., and pressurized to 70 kg / cm ² with an equimolar mixed gas of hydrogen and carbon monoxide,
The reaction was carried out for 16 hours. After completion of the reaction, the mixture was cooled to room temperature, the residual mixed gas was released, and the contents were analyzed by gas chromatogram to compare the reaction rates.

As a catalyst, 0.0001 mol of rhodium hydridocarbonyltristriphenylphosphine and 0.001 mol of triphenylphosphine were used with respect to the styrene fraction.

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display area C07B 61/00 300

Claims (1)

[Claims] 1. The following step (I), step (II), step (II)
A process for producing arylethylene comprising I) and step (IV). Step (I): contacting the 1,1-diarylethane represented by the general formula (A) with an acid catalyst in the presence of an inert gas,
A step of decomposing into arylethylene represented by the general formula (B) and / or the general formula (C) and an alkylbenzene represented by the general formula (D) and / or the general formula (E), step (II): the above decomposition From the reaction mixture obtained in step (I), a fraction mainly containing 1,1-diarylethane represented by the general formula (A) and an aryl represented by the general formula (B) and / or the general formula (C) Fraction containing mainly ethylene and general formula (D) and / or general formula (E)
A step of separating into a fraction mainly containing an alkylbenzene represented by: Step (III): a fraction mainly containing 1,1-diarylethane represented by the general formula (A), obtained in the above separation step (II) Is subjected to a hydrogenation treatment by bringing it into contact with a hydrogenation catalyst in the presence of hydrogen, and step (IV): the hydrogenation-treated fraction obtained in the above hydrogenation treatment step (III) is decomposed into the decomposition step (I ) And re-decompose. Formula _{(A) Ar 1 -CH (CH} 3) -Ar 2 formula _{(B) Ar 1 -CH = CH} 2 Formula _{(C) Ar 2 -CH = CH} 2 Formula (D) Ar ₁ -H General Formula (E) Ar ₂ —H In the above general formulas (A), (B), (C), (D) and (E), Ar ₁ and Ar ₂ are each a hydrogen atom or one having 4 or less carbon atoms or A phenyl group or an alkylphenyl group having a plurality of identical or different alkyl groups, wherein the total number of carbon atoms of the alkyl groups is 4 or less,
Ar ₁ and Ar ₂ may be the same or different.