JPS58216128A - Preparation of monoalkylbenzene - Google Patents

Abstract

PURPOSE:To prepare a monoalkylbenzene selectively in high yield, by reacting benzene with an alkylating agent using hydrogen ion exchanging mordenite type zeolite having specific acid strength as a catalyst. CONSTITUTION:In preparing a monoalkylbenzene by reacting benzene with an alkylating agent selected from an olefin, alcohol and alkyl halide in the presence of a catalyst, a hydrogen ion exchanging mordenite type zeolite exhibiting an acid strength (HO) shown by Hammett's function weaker than -8.2, especially hydrogen ion exchanging mordenite type zeolite showing an acid strength in a range of +3.3--5.6 is used. In this method, an olefin or alcohol among the alkylating agent is economically advantageous, and the use of the olefin is advantageous.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing monoalkylbenzenes selectively and in high yields by reacting benzene with an alkylating agent in the presence of a catalyst.

Monoalkylbenzenes such as cumene, butylbenzene, and pentylbenzene are useful as intermediates in the production of phenols, aromatic ketones, and others.

Conventionally, various methods have been proposed for producing these monoalkylbenzenes, including a method in which benzene is reacted with an alkylating agent such as an olefin, an alcohol, or an alkyl halide in the presence of an acidic catalyst such as a Lewis acid or a solid acid. There is. However, in any of these methods, a large amount of polyalkylbenzenes such as dialkylbenzene and trialkylbenzene are produced as by-products in addition to monoalkylbenzene during the reaction, and in some cases, a mixture of these equilibrium compositions is produced, and a mixture of these Distillation method, crystallization method,
Methods such as adsorption methods are used to separate monoalkylbenzene. Therefore, none of these methods can selectively produce monoalkylbenzene in high yield, and cannot be said to be a method for economically producing monoalkylbenzene on an industrial basis.

We have discovered that benzene (a) and alkylating agents such as olefins, alcohols or alkyl halides (
In the method for producing monoalkylbenzene by reacting b) in the presence of a catalyst, when a hydrogen ion exchange mordenite type zeolite having a specific acid strength is used as a catalyst, monoalkylbenzene can be produced selectively and in high yield. The present invention was achieved based on the discovery that the present invention can be obtained by

That is, the present invention produces monoalkylbenzene by reacting benzene (a) with one alkylating agent Cb) selected from the group consisting of olefins, alcohols, and alkyl halides in the presence of a catalyst. A method for producing monoalkylbenzene, which is characterized in that a hydrogen ion-exchanged mordenite type zeolite having an acid strength (Ho) expressed by Hammett's acidity function that is weaker than -8.2 is used as a catalyst.

The alkylating agent (b) used in the method of the present invention is one selected from the group consisting of olefins, alcohols and alkyl halides. Specific examples of the olefin include olefins usually having 3 to 3 carbon atoms, such as propentene, hexene\cyclohexene, and methylcyclohexene. Among these olefins, it is particularly preferable to use aliphatic olefins having 4 to 4 carbon atoms. Examples of alcohols include propatool, isopropanol, n-butanol, 18ea-butanol, tert-butanol, pentanol, hexanol, and cyclohexanol, which usually have 3 carbon atoms.
Alcohol can be given as an example. Among these alcohols, it is preferable to use aliphatic alcohols having 4 to 2 carbon atoms. In addition, specific examples of the alkyl halides include propyl fluoride, propyl chloride, propyl bromide, isopropyl fluoride, isopropyl chloride, inpropyl bromide, isopropyl iodide, n-butyl chloride, n-butyl bromide, n-butyl chloride,
5ea-butyl chloride, 5ea-butyl bromide, 8(I) iodide
Examples include alkyl halides usually having 3 to 2 carbon atoms such as Q-butyl, tert-butyl chloride, tert-butyl bromide, tert-butyl iodide, pentyl chloride, hexyl chloride, and cyclohexyl chloride.

Among these alkyl halides, the number of carbon atoms is 4
Preferably, alkyl chlorides in the range from 1 to 6 are used. Among the alkylating agents, it is economically advantageous to apply olefins or alcohols to the process according to the invention, and it is particularly advantageous to use olefins.

The catalyst used in the method of the present invention needs to be a hydrogen ion-exchanged mordenite-type zeolite that exhibits an acid strength (Ho) weaker than -8.2 as expressed by the Hammett function, and more preferably a Hammett It is a hydrogen ion-exchanged mordenite type zeolite which exhibits an acid strength expressed as a function in the range of +3.3 to -8.2, particularly preferably in the range of +6.3 to -5.6.

When the acid strength (Ho) expressed by the Hammett function becomes stronger than -8.2 (that is, when the value of Ho becomes smaller than -8.2), the selectivity to monoalkylbenzene decreases and the yield thereof also decreases. It becomes like this.

Methods for preparing the catalyst used in the method of the present invention include (1) a method of reacting a conventionally known hydrogen ion-exchanged mordenite type synthetic zeolite with a base;
Examples include 1) a method of heat treatment, and ω1) a method of heating in the presence of water.

Here, Hammett's acidity function (Ho) is calculated by the following formula when the neutral base B and the protons of the solution have an equilibrium relationship of B+H+::B-H" [where (p ka ) B H+ is the dissociation constant of BH+ C is the concentration, α is the activity, and f is the activity coefficient].

The mordenite-type zeolite used in the preparation of the catalyst used in the process of the invention is a zeolite having a skeleton structure belonging to the normal mordenite group. More specifically, the metal ion components of mordenite type zeolite are potassium ion, magnesium ion, and calcium ion, and the main metal ion is sodium ion. In addition, the SiO component and Al2 constituting this
Molar ratio with O3 component (s 102 / p-l 203
) is usually in the range of 9 to 10.

Its composition is generally expressed by the following formula.

M2/nO・Al2O3・(9~10)Sin2・6H
20 Here, M represents a metal ion component, and n represents its valence number. M may be a sodium ion, a potassium ion, a magnesium ion, a calcium ion, or a mixture thereof.

The skeletal structure of this mordenite-type zeolite has a crystal lattice in which Blo-A#04 tetrahedrons connected in a chain are connected in parallel in a bundle, and four of these unit chains are combined to form a 12-membered ring. The skeletal structure of mordenite-type zeolite is a honeycomb-like collection of tunnel-like parallel pore units that form the original pores and are open at both ends. The cross section of the pores of this zeolite has a maximum part of 7.1 mm when the metal ion is sodium ion.
X, the smallest part is a slightly flat circular shape of 5.9X,
As a whole, it belongs to the orthorhombic crystal form. This mordenite-type zeolite can be produced by a synthetic method, and since it is naturally produced as a mineral containing it, it can also be used in the method of the present invention. The hydrogen ion exchange mordenite type zeolite used in the method of the present invention is obtained by treating the above-mentioned mordenite type zeolite by a conventional method to convert the alkali metal or alkaline earth metal represented by M in the above general formula into hydrogen ions. It can be prepared by:

In the method of the present invention, benzene (
By reacting a) and the alkylating agent (b), an alkylated benzene mixture with a high monoalkylbenzene content can be produced. The reaction according to the method of the present invention is preferably carried out in a gas phase method,
It is also possible to carry out the process using a liquid phase method.

Any conventionally known method can be employed as the contact method when the method of the present invention is carried out by a gas phase method. For example, there may be a method of contacting using a fixed bed method, a method of contacting using a moving bed method, and the like. The temperature in the case of contacting in the gas phase method is usually in the range of 100 to 300°C, preferably 150 to 200°C, and the space velocity (LH8V) in the gas phase contact reaction is usually in the range of 0.1 to 1 Qhr, preferably 0.5 to 5. Dhr-1
is within the range of In addition, benzene (
The molar ratio of alkylating agent (b) to a) is usually 0.1
It ranges from 0.5 to 10, preferably from 0.5 to 5.

By treating the alkylated benzene mixture with a high monoalkylbenzene content obtained by the method of the present invention by a conventionally known monoalkylbenzene separation method such as distillation, cryogenic separation, or adsorption separation, Alkylbenzene can be obtained.

Next, the method of the present invention will be explained in more detail with reference to Examples.

Example 1 Synthetic Mordenai) (manufactured by Norton, trade name ZeO)
After drying 1on 100H) at 500°C for 3 hours, 30g of it was immersed in 200g of distilled water in which 0.6g of sodium hydroxide was dissolved, and stirred at room temperature for 10 hours.

Water distillation was performed using a rotary evaporator at 49. The catalyst was dried at 100°C for 20 hours, and then calcined at 500°C for 6 hours. The acid strength of the obtained catalyst was H6--5,6, and the Na content was 1.6 wt% as Na20.
Met. Powdered catalyst i f3rnl (5,0g
) was filled into a Pyrex reaction tube with an inner diameter of 20 mm, and then heated to 160°C. After reaching a predetermined temperature, a mixed solution of benzene/5ec-butyl alcohol with a molar ratio of 2 was supplied at a rate of 5 md/hr (LH8V O, 5hr-1) to carry out a reaction. The results are shown in Table 1.

Example 2 In Example 1, 0.6 g of IJium (hydroxide) was added to 1
．． A catalyst was prepared in the same manner except that the amount was changed to 3 g. The acid strength of the obtained catalyst was H9--3,3, and Na
The content was 3.5 wt% as Na2O.

Using this catalyst 10J, a reaction was carried out under the same conditions as in Example 1. The results are shown in Table 1.

Examples 3-4 In Example 1, the alkylating agent was changed from 5ea-butyl alcohol to butene-1 (Example 3), 2-chlorobutane (
The reaction was carried out under the same conditions as in Example 1 except for changing to Example 4). The results are shown in Table 1.

Example 5 The reaction was carried out under the same conditions as in Example 1 except that the alkylating agent was changed from 8eQ-butyl alcohol to cyclohexanol. As a result, the benzene conversion rate was 14%, the cyclohexylbenzene selectivity was 75 mol%,
The dicyclohexylbenzene selectivity was 21 mol%.

Comparative Examples 1 to 2 In Example 1, the catalyst was synthesized with synthetic mordenite (zeol).
on 100H) (Comparative Example 1), H-Y (Comparative Example 2
) The reaction was carried out under the same conditions as in Example 1 except that The results are shown in Table 1. The acid strength of these catalysts was H8=-11.4.

Claims (1)

[Claims] (1) A method for producing monoalkylbenzene by reacting benzene (a) with an alkylating agent (b) selected from the group consisting of olefins, alcohols, and alkyl rogens in the presence of a catalyst. ,
As a catalyst, the acid strength expressed by Hammett's acidity function (Ho
1. A method for producing monoalkylbenzene, characterized in that a hydrogen ion-exchanged mordenite type zeolite exhibiting an acid strength weaker than -8.2 is used.