JPH10251171A - Neutralization - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten neutralization time and treat an increased amount of a reaction mixture in a unit time using vessels of a small capacity by washing the reaction mixture of a specific olefin with an (alkyl)benzene in the presence of aluminum chloride with water, then neutralizing the oil layer separated after washing with water. SOLUTION: In this neutralization process, (A) a 2-4C olefin is allowed to react with (B) benzene and/or alkylbenzene in the presence of an aluminum chloride catalyst, and the resultant reaction mixture is washed with water, the oil layer is separated, and an aqueous alkali, preferably an aqueous sodium hydroxide solution of 3-10wt.% concentration, is added to effect the neutralization. The neutralization is required to maintain the oil layer at 80-120 deg.C, preferably 90-110 deg.C. The oil layer after the neutralization is fractionated by distillation and the objective alkylbenzene is collected. At the same time, unreacting benzene, alkylbenzenes other than objective alkylbenzene are recycled to the first reaction process and subjected to alkylation or transalkylation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a neutralization method. More specifically, in the present invention, a reaction solution obtained by reacting an olefin having 2 to 4 carbon atoms with benzene and / or alkylbenzene in the presence of an aluminum chloride catalyst is washed with water, and then an aqueous alkali solution is added to the separated oil layer. The present invention relates to a method for neutralizing an oil layer, which is a method that requires a short time for the neutralization reaction, and thus enables a large amount of treatment in a small-capacity container, and is particularly advantageous from the viewpoint of industrial implementation.

[0002]

2. Description of the Related Art A reaction for reacting an olefin having 2 to 4 carbon atoms with benzene and / or alkylbenzene in the presence of an aluminum chloride catalyst is known as a Friedel-Crafts reaction. The reaction solution obtained by the Friedel-Crafts reaction is subjected to a water washing step to deactivate the residual catalyst. The oil layer separated from the oil-water mixed layer obtained in the water washing step is neutralized by adding an aqueous alkali solution. This is because the oil layer after water washing becomes acidic due to the incorporation of the catalyst component, but if the oil layer showing acidity is directly subjected to the subsequent distillation step, corrosion of the apparatus occurs, which is inconvenient. By the way, according to the conventional method, a sufficiently long reaction time is required to complete the neutralization reaction sufficiently, and when a large amount of oil layer is neutralized per unit time in a small-capacity container, the acid component of There was a problem that a part of the reactor leaked downstream and a large-capacity reactor, which was economically disadvantageous, had to be used for the countermeasure.

[0003]

In view of such circumstances, an object of the present invention is to provide an olefin having 2 to 4 carbon atoms and benzene and / or benzene in the presence of an aluminum chloride catalyst.
Or a method of neutralizing an oil layer in which an aqueous alkali solution is added to an oil layer separated after washing a reaction solution obtained by reacting with alkylbenzene with an aqueous alkali solution. Accordingly, it is possible to treat a large amount of oil layer, and to provide an advantageous neutralization method particularly from the viewpoint of industrial implementation.

[0004]

That is, according to the present invention, a reaction solution obtained by reacting an olefin having 2 to 4 carbon atoms with benzene and / or alkylbenzene in the presence of an aluminum chloride catalyst is separated after washing with water. The present invention relates to a method for neutralizing an oil layer by adding an aqueous alkali solution to the oil layer, wherein the liquid temperature during neutralization is 80 to 120 ° C.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for reacting an olefin having 2 to 4 carbon atoms with benzene and / or alkylbenzene in the presence of an aluminum chloride catalyst is known as a so-called Friedel-Crafts reaction.

[0006] As the aluminum chloride catalyst, those usually used in the field of the present invention can be used.
Liquid aluminum chloride catalysts prepared from aluminum chloride and hydrogen chloride or ethyl chloride and a hydrocarbon oil are preferred.

[0007] Examples of the olefin having 2 to 4 carbon atoms include ethylene, propylene and butene. Examples of the alkyl group of the alkylbenzene include a methyl group, an ethyl group, an isopropyl group, and a butyl group. As the alkylbenzene, those containing 1 to 4 alkyl groups are usually used. For example, when the olefin is ethylene and the alkylbenzene is monoethylbenzene, diethylbenzene, triethylbenzene or tetraethylbenzene, the olefin is propylene and the alkylbenzene is monoisopropylbenzene, diisopropylbenzene or triisopropylbenzene. The olefin is propylene,
Examples include the case where the alkylbenzene is monoisopropyltoluene, diisopropyltoluene or triisopropyltoluene. These reactions include so-called alkylation reactions and / or transalkylation reactions. In the reaction, benzene or alkylbenzene usually also acts as a reaction solvent.

[0008] The reaction solution of the above reaction is subjected to a water washing step to deactivate the catalyst. The oil / water mixed layer obtained in the water washing step is separated into an oil layer and an aqueous layer. Since the separated oil layer contains the acidic components aluminum chloride and hydrogen chloride, it usually exhibits a pH value of about 1 to 3. The oil layer is neutralized by adding an aqueous alkali solution. As the alkali, sodium hydroxide (caustic soda) is usually used. The alkali concentration of the aqueous alkali solution is usually 3 to
10% by weight.

In the present invention, the temperature of the solution at the time of neutralization is from 80 to
It must be maintained at 120C, preferably 90-110C. If the liquid temperature is too low, the speed of the neutralization reaction is too slow to achieve the above object of the present invention. On the other hand, if the liquid temperature is too high, it is disadvantageous thermoeconomically, and furthermore, a high-grade material, which is less likely to cause caustic cracking, must be used as the material of the apparatus, which is also disadvantageous economically.

As a specific method for performing the neutralization reaction, an aqueous alkali solution is added to the oil layer to be neutralized, followed by stirring and mixing. As a method for maintaining the liquid temperature in the above range, a method in which a neutralization reactor having a steam jacket is used and heating is performed by the steam jacket and / or a steam heater (heater) can be mentioned.

In the oil layer after the neutralization, the desired alkylbenzene is separated and obtained by a distillation step, and benzene and alkylbenzene other than the desired alkylbenzene are recycled to the above-mentioned Friedel-Crafts reaction step to carry out alkylation or transalkylation. Attached to the reaction.

[0012]

Next, the present invention will be described by way of examples.

Example 1 An oil layer separated from a reaction solution obtained by reacting propylene with benzene and alkylbenzene in the presence of an aluminum chloride catalyst and then washed with water, comprising 5% by weight of benzene and 25% by weight of monoisopropylbenzene , Diisopropylbenzene 51% by weight, triisopropylbenzene 1
Oil layer containing 3.5% by weight (PH = 2) 14500k
g / hr was mixed with 13000 kg / hr of alkaline water circulated from a downstream neutralized oil / water separation tank, and a neutralization reaction was carried out in a neutralization reaction tank. The neutralization reactor is a reactor with a stirrer with a capacity of 10,000 liters.
The temperature was adjusted to 95 ° C. by heating through steam of g / cm ² G. The neutralized oil and water are sent to a neutralized oil / water separation tank. One part of the separated alkaline water is discharged out of the system so that the amount of alkaline water in the system is constant, and the remaining alkaline water is sodium hydroxide. An aqueous solution (30% by weight) and make-up water are added to prepare sodium hydroxide (5% by weight) and sodium chloride (2% by weight), and to 95 ° C. with a 1.5 kg / cm ² G steam double tube heat exchanger. It was heated and circulated upstream of the neutralization reactor. The neutralized reaction oil was washed with water to remove residual sodium hydroxide, and then benzene, monoisopropylbenzene, and water contained in the feed were separated at the top of the distillation column. The water contained in the vapor at the top was condensed with benzene and monoisopropylbenzene in a condenser, and then separated and discharged in a reflux tank.
At this time, the chlorine ion concentration in the wastewater was 500 ppm.

Comparative Example 1 An experiment was carried out in the same manner as in Example 1 except that the liquid temperature of the neutralization reaction was 70 ° C. The chlorine ion concentration in the wastewater discharged from the first tower reflux tank was 2000 ppm.

[0015]

As described above, according to the present invention, an oil layer separated after washing a reaction solution obtained by reacting an olefin having 2 to 4 carbon atoms with benzene and / or alkylbenzene in the presence of an aluminum chloride catalyst is washed with water. A method for neutralizing an oil layer by adding an aqueous alkali solution to the oil layer, the time required for the neutralization reaction is short, so that a large amount of processing can be performed per unit time with a small-capacity container, which is particularly advantageous from the viewpoint of industrial implementation. A neutralization method could be provided.

Claims (5)

[Claims] 1. An oil layer in which a reaction solution obtained by reacting an olefin having 2 to 4 carbon atoms with benzene and / or alkylbenzene in the presence of an aluminum chloride catalyst is washed with water and then an aqueous alkali solution is added to the separated oil layer. A neutralization method wherein the liquid temperature during neutralization is 80 to 120 ° C. 2. The method according to claim 1, wherein the olefin is ethylene and the alkylbenzene is monoethylbenzene, diethylbenzene, triethylbenzene or tetraethylbenzene. 3. The method according to claim 1, wherein the olefin is propylene and the alkylbenzene is monoisopropylbenzene, diisopropylbenzene or triisopropylbenzene. 4. The method according to claim 1, wherein the olefin is propylene and the alkylbenzene is monoisopropyltoluene, diisopropyltoluene or triisopropyltoluene. 5. The neutralization method according to claim 1, wherein a neutralization reactor having a steam jacket is used, and heating is performed using the steam jacket.