JPS5829722A - Preparation of diphenylalkane - Google Patents

Abstract

PURPOSE:To obtain the titled compound by reacting styrene, etc. with a mixed alkylbenzene obtained as a by-product of the thermal cracking of petroleum hydrocarbons, in the presence of anhydrous hydrogen fluoride, keeping the weight ratio of the total hydrocarbon to the anhydrous hydrogen fluoride, the dropping rate of the mixed alkylbenzene and the reaction temperature within specific ranges. CONSTITUTION:Diphenylalkanes are prepared by adding a 6-8C fraction or 8C fraction obtained as a by-product of the thermal cracking of petroleum hydrocarbons dropwise to benzene or a 1-4C alkylbenzene in the presence of anhydrous hydrogen fluoride. In the above process, the reaction is carried out by keeping the weight ratio of the total hydrocarbons to the anhydrous hydrogen fluoride to 1/2-1/200, preferably 1/50-1/100, the dropping rate of the 6-8C or 8C fraction to 130-0.5g/min.l preferably 70-1.0g/min.l in case of 6-8C fraction and 20-0.05g/min.l, preferably 10-0.1g/min.l in case of 8C fraction, and the reaction temperature at 0-100 deg.C, preferably 15-60 deg.C. USE:Synthetic oil for plasticizer, solvent, thermal medium, electrical insulation oil, hydraulic oil, refrigerator oil, etc.

Description

Detailed Description of the Invention The present invention relates to a method for producing diphenylalkanes. According to the method of the present invention, the desired diphenylalkanes can be efficiently produced. What are diphenylalkanes?
It has a diphenylmethane skeleton in which two benzene rings are bonded to the same carbon atom. Diphenylalkanes have excellent heat resistance, compatibility, and electrical properties, and are widely used as synthetic oils suitable for plasticizers, solvents, heat carriers, electrical insulation oils, hydraulic oils, refrigeration oils, etc. Particularly suitable as plasticizers, solvents, etc. are those with low levels of by-product triphenylalkanes.

Is it possible to produce diphenylalkanes by reacting mixed alkylbenzene, a by-product of thermal decomposition of petroleum hydrocarbons, with styrene or styrene-based compound 4N? The method is known. For example, JP-A-48-47858 discloses a method using hydrogen fluoride as a catalyst. However, in this case, a large amount of resinous material is produced, making it impossible to obtain the desired product, and this problem has not been solved in the above-mentioned catalyst system since then (Japanese Patent Laid-Open No. 53
(Refer to Publication No.-135959). Furthermore, in these methods, since 1/lI-made styrene or styrene-based compounds are used, the cost of diphenylalkanes is high and it is preferable that tL<l. Furthermore, JP-A-53-130624 discloses a method in which a xylene fraction containing styrene is brought into contact in a liquid phase with an acid catalyst excluding a halogenated metal.
When sulfuric acid is used as a catalyst, aromatic compounds and sulfonated unsaturated aliphatic hydrocarbons are produced as by-products, resulting in significant emulsification of the reaction solution, making it difficult to separate the oil layer and acid L-, and preventing the target product from being separated. A problem occurred where the recovery rate was extremely low.

On the other hand, the addition of styrenes to benzene or alkylbenzenes not only produces diphenylalkanes, which are 1 molar adducts, but also produces triphenylalkanes, which are 2 molar adducts, and styrenes to diphenylalkanes. The present inventors conducted extensive studies to solve the above problems, and found that when using a C6-C8 fraction or a C8 fraction that is a by-product of thermal decomposition of petroleum hydrocarbons, We have discovered that even if anhydrous hydrogen fluoride is used as a catalyst, the above problems can be solved by selecting specific production conditions, and diphenylalkanes can be obtained efficiently and in high yields, leading to the completion of the present invention. Ta.

That is, the present invention provides C6-C byproducts in benzene or Cl-04 alkylbenzene during thermal decomposition of petroleum hydrocarbons.
A method for producing diphenylalkanes in the presence of anhydrous hydrogen fluoride by applying the m-fraction or C-fraction, wherein the weight ratio of total hydrocarbons to anhydrous hydrogen fluoride is 1/2 to 1/z.
o o, the dropping rate of Cs-Cs fraction or C fraction is C
In the case of 6-C8 fraction, 130-0.5 f/min・t, C,
For fractions 20~o, o s t7;')-t.

The object of the present invention is to provide a method characterized in that the reaction temperature is 0 to 100°C.

The C6 to Ca fraction produced by the thermal decomposition of petroleum hydrocarbons used in the method of the present invention refers to the pyrolysis oil of petroleum hydrocarbons such as naphtha, gasoline, melt oil, and light oil, which has a boiling point range. It is a fraction of 70-165℃, and this fraction contains C- to C-C.
The aromatic compounds of I include benzene, toluene, ethylbenzene, xylenes, styrenes, C3 alkylbenzenes, as well as unsaturated aliphatic hydrocarbons, saturated aliphatic hydrocarbons, and the like. The C8 fraction is a fraction of the pyrolysis oil with a boiling point range of 115 to 155°C, and this fraction contains other hydrocarbons excluding benzene from the Ca to cm fraction. .

C@~C8 fraction and Ca'jl1 used in the method of the present invention
The unsaturated aliphatic hydrocarbons contained in the fraction are usually present in an amount of about 2 to 20 wt%. These unsaturated aliphatic hydrocarbons react with styrene, and together with the styrene consumed during polymerization, reduce the effective conversion rate of styrene as a whole. When using a C6-cm fraction or a fraction that contains only a trace amount in place of the C-fraction, a new problem arises that did not exist when using a fraction instead of the C.sub.6-cm fraction or the C.fraction. However, the method of the present invention also solves the above problems.

CI-Ca alkylbenzene used in the method of the present invention, toluene, xylenes, ethylbenzene, isobutylbenzene, n-butylbenzene, isoglobylbenzene, n-j propylbenzene, diethylbenzene, t
-Butylbenzene and the like are used.

In the method of the present invention, a predetermined amount of benzene or C1-
C4 alkylbenzene and anhydrous hydrogen fluoride are charged and maintained at a predetermined temperature. While stirring this reaction system, a C- to Cs fraction or a C8 fraction is added dropwise at a predetermined dropping rate. The target product, diphenylalkane, is obtained by combining 1 mole of styrenes in the Cm to C8 fraction or the C8 fraction, and benzene or C1 to C8.
It is produced by the reaction of 1 mole of Ca alkylbenzene. At this time, by-products such as a product with 2 moles of styrene added, heavy alkylbenzene resulting from the reaction of an aliphatic olefin with benzene or C1-C4 alkylbenzene, and a polymer of olefins are produced. These by-products are
After the reaction, it is separated by distillation.

The weight ratio of anhydrous hydrogen fluoride to the total hydrocarbons in the reaction system is 1/2 to 1/200. Preferably 1/10 to 1/20
0. More preferably, it is 115o to 1/100. When the amount of anhydrous hydrogen heptafluoride used is large, the regular reaction proceeds and the yield of diphenylalkanes decreases. When the amount of anhydrous hydrogen fluoride used is small, the reaction rate decreases.

To increase the yield of diphenylalkanes, C- to C8
It is necessary to adjust the rate of dropping the fraction or C8 fraction into the reaction system. More specifically, C6-C8 fraction or C8
The fractions are converted into reaction unit liquid volumes of 130 to 0, respectively.
．． 55F/min-t, 20-0.05t/min-t, preferably 70-1.01/min-t110-0.1, respectively
#1 Adjust the dropping speed of the Cs to Ca fraction or cm fraction. If the dropping speed is high, the rate of polymerization of styrenes increases and the yield of diphenylalkanes decreases. On the other hand, the dropping speed If it is slow, the overall production rate will be slow, and the reactor volume required to obtain a constant production amount will increase significantly.
Not economical. In addition, when dropping the C6 to Cs fraction or the C8 fraction, the fraction can also be sprayed and introduced from 7 nozzles.The reaction temperature is preferably 0 to 100°C, particularly 15 to 6
0°C is preferred. If the reaction temperature is too low, the yield of diphenylalkanes will decrease, and if the reaction temperature is too high, the polymerization reaction of styrene will become faster, and the yield of diphenylalkanes will also decrease.

Although the reaction pressure is not particularly limited, it is preferably a pressure necessary for anhydrous hydrogen heptafluoride to remain in a liquid state at a predetermined reaction temperature.

In the present invention, it is preferable to maintain the concentration of the reaction product in the reaction system at 50% by weight or less based on the total amount of hydrocarbons in the reaction system. The concentration of the reaction product is 50% by weight
When the amount exceeds 100%, the amount of heavy substances as by-products increases and the yield of diphenylalkanes decreases.

When using the reaction conditions of the present invention, the trace amount of water contained in the reaction system is not a particular problem.However, as the amount of water contained in the reaction system increases, the production of polymer products as by-products increases. , the yield of diphenylalkanes decreases. C
When the dropping rate of the 6-C8 fraction or the Q fraction is fast, the yield of diphenylalkanes decreases as the water content in the reaction system increases. For this reason, it is preferable to keep the moisture content in the reaction system for anhydrous hydrogen fluoride at 2% or less. Since the ratio of water to hydrogen is relatively large, it is preferable to use sufficiently dehydrated raw materials.

After completion of the reaction, hydrogen fluoride is separated by static separation when anhydrous hydrogen heptadide is used at least 1000 times the weight of all hydrocarbons. Hydrogen fluoride is recovered from the lower layer and returned to the reaction system for reuse.

Hydrocarbons containing diphenylalkanes in the upper layer are treated with an alkaline aqueous solution and washed with water, or by gentle heating to evaporate and remove hydrogen fluoride.

Thereafter, alumina treatment is performed as necessary, and then diphenylalkanes are obtained by distillation. If the 9-diphenylalkanes recovered by distillation are colored, the color can be improved using activated clay, activated carbon, silica gel, activated alumina, etc. Such adsorption treatment is also effective in reducing the bromine number and deodorizing. There is.

The present invention will be explained below with reference to Examples and Comparative Examples.

Example 1 A C6-C8 fraction with a boiling point of 70-165°C and an SCMM fraction with a boiling point of 111-155°C were separated by distillation from hydrocarbons produced as a by-product during the thermal decomposition of naphtha. The compositions of these fractions are shown below.

C6-C8 fraction C8 fraction benzene 46.2 wt% -Toluene: 23.5 1 1.6 wt% xylenes ' 9.7 t 32.1
zEthylbenzene: 2.0 g 6.
2 g styrene '4.8 N
31,5 ttCa'Trukylbenzene: 0
．． 3 #5.5 z Saturated hydrocarbon:
5.6# 9.8# unsaturated hydrocarbon 1L:
7.6N 13.2#Total 100. Ott
100.0 #10 with internal coil and external jacket
4132F (4,75t) in a Monel autoclave.
) mixed xylene (0-xylene: 16.OW1%,
m-xylene: 29.9 wt%, p-xylene:
12.8 wt collection, ethylbenzene: 40.1 w@
%, -'F: (D and others: 1.2w1%) and 611F anhydrous hydrogen fluoride are added and maintained at 30C. 260 tons for this
(0.3 t) of the above C8 fraction was added dropwise at a dropping rate of 1.8 #1 min·t. Since the reaction is an exothermic reaction, the temperature of the reaction water was adjusted to 30°C by passing a refrigerant through the inner coil of the autoclave and passing hot water through the outer jacket when dropping the distillate.

After the reaction, the reaction solution was neutralized with a 5% aqueous solution of caustic soda, washed with water, dried over anhydrous calcium chloride, and removed excess unreacted aromatic compounds under reduced pressure.
134 was collected from the fractions 139 to I41C. The collected fractions were confirmed to be diphenylalkanes by refractive index, infrared absorption spectrum, mass spectrometry, and gas chromatography.

Examples 2 to 6, Comparative Examples 1 to 6 Diphenyl alkanes were synthesized in the same manner as in Example 1, except that the raw materials, reaction conditions, etc. were changed to those shown in Table 1. The results are shown in Table-1.

Example 7 Mixed xylene: 2500 f (2,87 t')
The reaction was carried out in the same manner as in Example 1, except that the C6 to Ca fraction: 1700F (1,96 t) and the dropping rate were 55 t/min.t. After the reaction, unreacted aroma was removed in the same manner as in Example 1. After removing the group compounds, 120
1261 fractions of ~141°C were collected.

The collected fraction was analyzed in the same manner as in Example 1, and it was confirmed that it was the diphenylalkanes of the present invention (blank below) Comparative Example 7 Mixed xylene: 344.5 f, CS fraction: 1351
P.

Cs fraction dropping rate: 11.4y1 min/t, 80% sulfuric acid as a catalyst: 100F, reaction temperature: 15°C, Cs fraction dropping time: 30 minutes, reaction aging time after dropping was near 0 minutes. The reaction was carried out in the same manner as in Example 1, and diphenylalkanes were recovered. The yield of recovered diphenylalkane was 21 mol%. In addition, since separation of sulfuric acid and hydrocarbons is poor even if left standing day and night, 2
The total recovery rate of hydrocarbons was 6 times.
It was only 4%.

It is clear from the Examples and Comparative Examples that the desired diphenylalkanes can be efficiently produced by the method of the present invention.

Patent applicant: Mitsubishi Yuka Co., Ltd. Agent: Patent Attorney Hidetoshi Furukawa Agent: Patent Attorney Masahisa Nagatani

Claims (1)

[Claims] Benzene or 4d Ct-Ca alkylbenzene,
A C6 to C8 fraction or a C8 fraction produced by thermal decomposition of petroleum hydrocarbons is added dropwise, and in the presence of anhydrous hydrogen fluoride, 1/20
The dropping rate of 0.06~aS fraction or cm fraction is C6~C
In the case of Hatake fraction, 130~o, sy1min・l-s In the case of Cs fraction, 20~0.05 f/min・t, reaction temperature is 0~1
A method characterized in that the temperature is 00°C.