JPH03246236A - Preparation of diphenylbutane - Google Patents

Abstract

PURPOSE:To prepare the subject compound in a good yield and reuse sulfuric acid while depressing side-reactions by adding a specific amount of benzene sulfonic acid to the reaction system when 1-phenyl butene is reacted with ben zene in the presence of the sulfuric acid catalyst to provide the objective com pound. CONSTITUTION:When 1-phenyl butene is reacted with benzene in a molar native of 1:5-30 in the presence of 89-98wt.% (preferably 90-95wt.%) sulfuric acid cata lyst at 20-50 deg.C to prepare the subject compound, benzene sulfonic acid is added to the sulfuric and in an amount of 7-50mol% (preferably 20-35mol%) based on the sulfuric acid. The method gives the objective compound useful as a solvent for pressure-sensitive copy paper, a thermal medium ail, an electrically insulating oil, etc., in a high yield, and permits the economical recovery and reuse of the sulfuric acid because the by-production of benzene sulfone compounds is depressed to prevent the lowering of the purity of the sulfuric acid.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a method for producing diphenylbutane, and more specifically, a method for producing diphenylbutane that can be used as a solvent for pressure-sensitive copying paper, as well as in heat transfer oil, electrical insulation oil, etc. Regarding.

Technical Background of the Invention Diphenylbutane is a compound useful as a solvent for pressure-sensitive copying paper, heat transfer oil, electrical insulation oil, etc., but the following methods have been known as methods for producing diphenylbutane. ing.

(a) A method for producing diphenylbutane from benzene and butadiene in a one-step reaction using 96% sulfuric acid or hydrogen fluorine as a catalyst (Journal of American Chemical Society 1944, Vol. 66, 816)
~817 pages), (b) A method for producing diphenylbutane from benzene and butadiene in a one-step reaction using concentrated sulfuric acid or aluminum chloride as a catalyst (Journal.
Of Organic Chemistry 1966, No. 3
1, pp. 1124-1127).

However, the method for producing diphenylbutane disclosed in the above-mentioned document has a problem that the yield of diphenylbutane is low (the yield based on butadiene is only about 15% at most, and there are extremely large amounts of by-products such as butadiene polymers). There was a point.

(c) The present applicant has also proposed a method for producing diphenylbutane in which 1-phenylbutene and benzene are reacted in the presence of 89 to 96% by weight of a sulfuric acid catalyst (Japanese Patent Laid-Open No. 63-239239). Public bulletin).

Although the above method is an excellent production method that significantly improves the yield of diphenylbutane, a side reaction occurs in which benzene, which is a reaction raw material, is sulfonated with sulfuric acid, and as a result, the purity of sulfuric acid, which is a catalyst, decreases. There was a problem in that sulfuric acid could not be recovered and reused as a catalyst.

Purpose of the Invention The present invention aims to solve the above-mentioned problems associated with the conventional technology when producing diphenylbutane. The purpose of the present invention is to provide an economical method for producing diphenylbutane.

Summary of the Invention The present inventors have investigated various methods for producing diphenylbutane using sulfuric acid as a catalyst.

As a result, 1-phenylbutene and benzene were 89 to 9
When producing diphenylbutane by reacting in the presence of 8% by weight sulfuric acid catalyst, by adding a specific amount of benzenesulfonic acid to the reaction system, diphenylbutane can be obtained in high yield, and the benzenesulfonated product can be produced in a high yield. The present inventors discovered that the production of sulfuric acid was suppressed and that the sulfuric acid catalyst could be recovered and reused, leading to the completion of the present invention.

That is, in the present invention, when producing diphenylbutane by reacting 1-phenylbutene and benzene in the presence of 89 to 98% by weight of a sulfuric acid catalyst, benzenesulfonic acid is added in an amount of 7 to 50 mol% based on the sulfuric acid. It is characterized by being added to the reaction system.

DETAILED DESCRIPTION OF THE INVENTION The method for producing diphenylbutane according to the present invention will be specifically described below.

In the present invention, 1-phenylbutene, which is used as a reaction raw material when producing diphenylbutane, can be produced in high yield from benzene and butadiene by a known production method.

Known manufacturing methods include, for example, the following method.

(a) Benzene and butadiene (471 molar ratio), 9
A method of obtaining phenylbutene by reacting at a reaction temperature of 60 to 65°C in the presence of a 5% phosphoric acid catalyst.

(Yield 60%, of which I-phenyl-2-butene selectivity: 94.4%)
nntroll-Chemie) 1963, No. 44
Vol. 6, p. 175], (b) A method for obtaining phenylbutene by reacting benzene and butadiene (2/1 molar ratio) in the presence of a BF-phosphoric acid catalyst at a reaction temperature of 85 to 88°F. (yield 80%
above) (U.S. Patent No. 2.412595, No. 2
．． 471.922) etc.

Diphenylbutane can be obtained by reacting I-phenylbutene and benzene as described above, and in this case, 89 to 98% by weight, more preferably 90 to 95% by weight.
of sulfuric acid as catalyst. This 89-98% by weight sulfuric acid catalyst is used in an amount of 2-200% by volume, more preferably 5-100% by volume based on 1-phenylbutene and benzene as reaction raw materials.

In the present invention, when reacting 1-phenylbutene and benzene using the sulfuric acid catalyst as described above, benzenesulfonic acid is added in an amount of 7 to 50 mol%, preferably 20 to 35 mol%, based on the sulfuric acid. Add to reaction system. If the amount of benzenesulfonic acid added is less than 7 mol% based on the sulfuric acid, the benzene sulfonation reaction will proceed, and the purity of the sulfuric acid as a catalyst will decrease, making it impossible to reuse. Exceeding this is not preferable because the yield of diphenylbutane decreases.

Further, in the present invention, the molar ratio of benzene/1-phenylbutene is 3 to 40, more preferably 5 to 30. If the molar ratio is less than 3, the sequential reaction of the target product will progress and the yield will decrease, which is undesirable. On the other hand, if the molar ratio exceeds 40, no good results will be produced, which is undesirable.

The reaction between 1-phenylbutene and benzene according to the present invention can be carried out in any of a batch method, a semi-batch method, and a continuous method.

The reaction temperature is 0 to 70°C, more preferably 20 to 50°C in order to suppress side reactions such as sulfonation reactions, and the reaction time is 0.5 to 3.0 hours, more preferably 1
．． It is 0 to 2.5 hours. Furthermore, in order to suppress the polymerization reaction, it is preferable to maintain the concentration of 1-phenylbutene in the reaction system at 5% by weight or less.

The diphenylbutane produced by the production method according to the present invention usually contains 70 to 90% by weight of 1,1-diphenylbutane and 5 to 15% by weight of 2-diphenylbutane.
It is an isomer mixture in which 1,3-diphenylbutane is about 5 to 15% by weight.

Effects of the Invention According to the method for producing diphenylbutane according to the present invention, 1
-When reacting phenylbutene and benzene in the presence of a sulfuric acid catalyst, benzenesulfonic acid is added to the reaction system, so side reactions such as benzene sulfonation or phenylbutene polymerization can be suppressed. Therefore, diphenylbutane can be produced with good yield.

In addition, according to the method for producing diphenylbutane according to the present invention, the production of benzene sulfonated products is suppressed, so that the purity of sulfuric acid, which is a catalyst, does not decrease, and therefore, it can be recovered and reused, resulting in reduced cost. Excellent in

EXAMPLES The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples.

Note that the percentages in the examples are based on weight unless otherwise specified.

Example 1 40 mL of 95% sulfuric acid was added as a catalyst to a jacketed acid-resistant metal reactor with a capacity of 700 mL and a stirrer and a baffle.
l (72 g), 39 g of benzenesulfonic acid (35 mol% relative to sulfuric acid) and 230 ml of benzene (202+
r) was introduced and the internal temperature was set at 50°C.

Thereafter, a mixture of benzene and 1-phenyl-2-butene at a molar ratio of 12:1 was supplied to the reactor maintained at 50° C. for 2 hours using a metering pump. The supplied benzene and 1-phenyl-2-butene were each
They were 40 ml (300 g) and 50 ml (43 g).

After supplying the mixture, it was maintained at 50° C. for an additional 30 minutes while stirring, and then the stirring was stopped and left standing for 15 minutes. After separating the sulfuric acid layer and the organic layer in the reactor, the organic layer was washed and neutralized with a 2096 caustic soda aqueous solution, and the product was concentrated using gas chromatography.

Diphenylbutane was produced again under the same conditions as above using the sulfuric acid containing benzenesulfonic acid recovered above.

The reaction conditions and diphenylbutane yield are shown in Table 1.

The 1-phenyl-2-butene used was produced from benzene and butadiene in the presence of a phosphoric acid catalyst at a yield of 80% based on butadiene.

Examples 2-4 and Comparative Examples 1-2 Production of diphenylbutane and production of diphenylbutane using recovered sulfuric acid in the same manner as in Example 1 except that the amount of benzenesulfonic acid added was changed as shown in Table 1. was manufactured.

The reaction conditions and diphenylbutane yield are shown in Table 1.

Example 5 Diphenylbutane was produced and the sulfuric acid catalyst was recovered in the same manner as in Example 1. From the recovered sulfuric acid containing 115g of benzenesulfonic acid, 23g-(20g of recovered sulfuric acid)
%) was extracted and 23 g of 98% sulfuric acid was newly replenished.

Diphenylbutane was produced again under the same conditions using the sulfuric acid prepared above. The above method was repeated a total of three times.

Table 2 shows the yield of diphenylbutane for each reaction.

Comparative Example 3 Example 1 except that benzenesulfonic acid was not added.
Diphenylbutane') was produced and the sulfuric acid catalyst was recovered in the same manner as above. 30 g (35% of the recovered sulfuric acid) of 86 g of sulfuric acid containing various sulfonated products as recovered by-products was extracted, and 30 sr of 98% sulfuric acid was newly replenished. Using the sulfuric acid prepared above, under the same conditions again,
Diphenylbutane was manufactured.

The yield of diphenylbutane for each reaction is shown in Table 2.

Reference Example 1 200 ml (176 g) of benzene and 50 ml of 95% sulfuric acid (
91 g) were introduced, the internal temperature was kept at 50° C., and the mixture was stirred for 1 hour. After stopping the stirring, the mixture was allowed to stand still to separate the sulfuric acid layer and the benzene layer, and the recovered sulfuric acid was titrated with a 1N aqueous solution of caustic soda to determine the amount of sulfuric acid loss consumed by the sulfonation of benzene.

The results are shown in Table 3.

Reference Examples 2 to 4 The same experiment as in Reference Example 1 was conducted, except that benzenesulfonic acid was added as shown in Table 3, and the amount of sulfuric acid loss was determined.

The results are shown in Table 3.

Example 6 Diphenylbutane was produced in the same manner as in Example 1, and diphenylbutane was produced using the recovered sulfuric acid, except that the concentration of sulfuric acid used as a catalyst was changed from 95% to 98%.

The reaction conditions and diphenylbutane yield are shown in Table 1.

Claims (1)

[Claims] (1) When producing diphenylbutane by reacting 1-phenylbutene and benzene in the presence of 89 to 98% by weight sulfuric acid catalyst, benzenesulfonic acid is reacted in an amount of 7 to 50 mol% relative to sulfuric acid. A method for producing diphenylbutane, which comprises adding the diphenylbutane to a system.