JPH04230332A - Production of alkylbenzene - Google Patents

Abstract

PURPOSE:To efficiently produce an alkylbenzene from benzene and an alkylating agent by using a solid acid catalyst. CONSTITUTION:Reactors charged with a solid acid catalyst are connected in series, a base removing process is carried out between the reactors and an intermediate oil formed is subjected to base removal treatment.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing alkylbenzene, and more particularly to a method for producing alkylbenzene by alkylating benzene using a solid acid catalyst.

0002

[Prior Art] As a method for producing alkylbenzene, a method is known in which benzene is reacted with an alkylating agent such as an olefin or alkyl alcohol using a solid acid catalyst (December 1, 1960, Co., Ltd.) Published by Gihodo, “Zeolite and Its Uses” Edited by Editorial Committee, Zeolites and Their Uses). Furthermore, when carrying out a fixed bed catalytic reaction industrially, it is known to use a plurality of reactors connected in series in order to improve the efficiency of the reaction. However, when the present inventor produced alkylbenzene using a plurality of reactors connected in series and filled with solid acid catalysts, the efficiency of the reaction was not necessarily good. According to the knowledge obtained by the present inventors, this tendency was remarkable when the degree of reaction in the first reactor was low.

0003

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for efficiently producing alkylbenzene from benzene and an alkylating agent using a solid acid catalyst.

0004

[Means for Solving the Problems] As a result of various studies in order to solve the above-mentioned problems, the present inventor has developed an abasification treatment process between a plurality of reactors connected in series and filled with solid acid catalysts. In particular, the inventors completed the present invention by discovering that when a debasing treatment column filled with activated clay is provided, the life of the solid acid catalyst packed in the latter reactor is extended and the yield of alkylbenzene is improved.

That is, the present invention provides a method for producing alkylbenzene by flowing benzene and an alkylating agent through a plurality of reactors connected in series and filled with a solid acid catalyst, in which debasing treatment is performed between the reactors. This is a method for producing alkylbenzene, which is characterized by providing a step. In addition, benzene and an alkylating agent are passed through two or three reactors connected in series and filled with zeolite catalysts so that the amount of the alkylating agent is 1 to 4 moles per 10 moles of benzene to produce alkylbenzene. In the method for producing , the intermediate oil produced by the reaction of 20 to 40% of the alkylating agent with benzene in the first reactor is passed through a debasing treatment vessel filled with activated clay and heated to a temperature of 10 to 250°C. °C, LHSV0.3~3H
This is a method for producing alkylbenzene, which is characterized in that the alkylbenzene is processed under the conditions of r-1 and then distributed to a second reactor.

[0006] Benzene used as a raw material in the present invention includes coal-based or petroleum-based ones.
Some are obtained by refining gas light oil or tar light oil. As an industrial method for refining benzene, there is a method in which benzene is extracted from hydrogenated and refined raw material oil using a sulfolane solvent, and the extract is distilled to recover benzene. In order to prevent the distillation equipment from being corroded by acidic substances, nitrogen-containing bases such as amines must be added as anticorrosive agents when distilling the extract. Mixed with benzene, its nitrogen content is usually 0 in terms of elemental N.
．． It is about 0.01 to 1 ppm. Generally, when benzene is used as an industrial raw material, there is no problem even if it contains this much basic substance, but when benzene is alkylated using a solid acid catalyst, the basic substance in benzene is have a negative impact.

[0007] Examples of alkylating agents include olefins and alkyl alcohols. The amount of benzene and alkylating agent to be used depends on the type of target alkylbenzene. If monoalkylbenzene is to be obtained selectively, the amount of alkylating agent to be used is 1 to 10 moles of benzene.
It is recommended that the amount be 4 moles.

[0008] Examples of solid acid catalysts include aluminosilicates, and zeolites are a typical example. When using benzene containing a basic substance, the catalytic activity of zeolite decreases significantly, so the use of the present invention is particularly effective. In the present invention, benzene and an alkylating agent are connected in series and passed through a plurality of reactors filled with solid acid catalysts to cause an alkylation reaction.

[0009] Then, a debasing treatment step is provided between the reactors, and after the intermediate oil that has undergone a certain degree of alkylation reaction is treated in the first stage reactor, the alkylation reaction is further carried out in the second stage reactor. let For the debasing process, there are treatment vessels filled with fillers that have debasing effects such as activated clay, zeolite, activated carbon, silica gel, alumina, and ion exchange resins, among which treatment towers filled with activated clay are inexpensive. It is also effective. No matter where the abasic treatment step is placed, it will have some effect, but when trying to obtain a monoalkylated product and using 1 to 4 moles of alkylating agent per 10 moles of benzene. for,
It is preferable to provide a debasing treatment step at the stage when 20 to 40% of the alkylating agent has reacted with benzene. The optimum operating conditions for the debasing treatment process vary depending on the properties of the intermediate oil to be treated and the type of filler, but usually the temperature is 10 to 250°C,
Pressure 1~50Kg/cm2, LHSV0.3~3Hr
-1 level is good.

Next, a preferred embodiment of the present invention will be explained according to the flowchart shown in FIG. Raw material benzene is passed through pipe 1 and alkylating agent is passed through pipe 2 to a reactor 3 filled with a solid acid catalyst. Intermediate oil is extracted from the reactor 3 through a pipe 4 and flows to a debasing treatment tower 5. The treated intermediate oil is extracted from the debasing treatment tower 5 through a pipe 6 and flows into a reactor 7 filled with a solid acid catalyst. The alkylated oil is extracted from the reactor 7 through a tube 8 and charged into a distillation column 9, and the light fraction containing unreacted benzene as a main component is extracted from the top of the column through a tube 10 that joins the tube 1 and reacts. Recycle into container 3. On the other hand, an alkylated fraction is extracted from the bottom of the distillation column 9 through a pipe 11 and charged into a distillation column 12, and the target alkylbenzene is recovered from the top of the tower through a pipe 13. Then, the heavy fraction is extracted from the bottom of the distillation column 12 through the pipe 14 and charged into the distillation tower 15, and the heavy residue is removed from the bottom of the tower through the pipe 16. A fraction containing alkylbenzene as a main component is extracted from the top of the column through a pipe 17, merges with a portion of a light fraction containing unreacted benzene as a main component extracted through a pipe 10, flows into a transalkylation reactor 18, and flows into a transalkylation reactor 18. Alkylate. The transalkylated oil is withdrawn from the transalkylation reactor 18 through a tube 19 and is combined with the alkylated oil withdrawn from the reactor 7 through a tube 8.

[0011]

EXAMPLE Ethylbenzene was produced from benzene (JIS-K8858) and ethylene using the equipment shown in the flowchart of FIG. The amounts of benzene and ethylene used were 3 moles of ethylene per 10 moles of benzene. Also,
A zeolite catalyst was used as the solid acid catalyst, and activated clay (trade name: Nikkanite) was used as the filler for the debasing treatment tower 5. The operating conditions of reactor 3 are a temperature of 212°C, a pressure of 38 kg/cm2, and a gas space velocity of 10 hr-1.
The operating conditions of the debasing treatment tower 5 are a temperature of 180 to 2
00℃, pressure 30kg/cm2, LHSV1.5hr
−1, and the operating conditions of reactor 7 are: temperature 212°C;
Pressure: 38 kg/cm2, gas space velocity: 10 hr-1
And so. The lifespan of the zeolite catalyst filled in reactor 7 was estimated to be about 50 months.

As a comparative example, when the intermediate oil extracted from the reactor 3 through the pipe 4 was made to flow directly to the reactor 7 without passing through the debasing treatment tower 5, the zeolite catalyst packed in the reactor 7 was Its lifespan was estimated to be about 20 months. Note that the life of the catalyst was calculated from the moving speed of the hot spot in the reactor 7 during the reaction. The hot spot referred to here is a location where a reaction is actively occurring within the reactor, and is a location where the temperature is relatively higher than the surrounding area. It is thought that the hot spot moves to the outlet side as the activity of the catalyst on the reactor inlet side decreases.

[0013]

According to the present invention, the yield of alkylbenzene is high and the life of the solid acid catalyst is extended, so that alkylbenzene can be produced efficiently.

[Brief explanation of the drawing]

FIG. 1 is a flowchart of an embodiment of the invention.

[Explanation of symbols]

3 Reactor filled with solid acid catalyst 5 Debasing treatment tower 7 Reactor filled with solid acid catalyst

Claims (2)

[Claims] Claim 1: In a method for producing alkylbenzene by flowing benzene and an alkylating agent through a plurality of reactors connected in series and filled with solid acid catalysts, a debasing treatment step is provided between the reactors. A method for producing alkylbenzene, characterized by: 2. Benzene and an alkylating agent are distributed through two or three reactors connected in series and filled with zeolite catalysts such that the alkylating agent is 1 to 4 moles per 10 moles of benzene. In the method for producing alkylbenzene, 20 to 40% of the alkylating agent is
% reacts with benzene and the intermediate oil produced is passed through a debasing treatment vessel filled with activated clay and heated to a temperature of 10 to 250°C.
, LHSV0.3 to 3Hr-1, and then flowing to a second reactor.