JP4400433B2 - Monochlorobenzene production method - Google Patents

Description

  The present invention relates to a method for producing monochlorobenzene. More specifically, the present invention relates to a method for producing monochlorobenzene, which is obtained by reacting benzene and chlorine to obtain monochlorobenzene, and has a superior characteristic of obtaining monochlorobenzene in high yield from benzene. Is.

  A method for obtaining monochlorobenzene by reacting benzene and chlorine is known (see, for example, Patent Document 1, Patent Document 1, and Non-Patent Document 1).

  However, the conventional technique has a problem that monochlorobenzene cannot be obtained from benzene in a high yield.

US Pat. No. 3,128,240 Japanese Patent Publication No. 50-34010 Hydrocarbon Processing Vol. 52, No. 12, pp. 73-89

  In such a situation, the problem to be solved by the present invention is a process for producing monochlorobenzene by reacting benzene and chlorine to obtain monochlorobenzene, which has an excellent feature of obtaining monochlorobenzene from benzene in a high yield. The object is to provide a method for producing monochlorobenzene.

  That is, the present invention is a method for producing monochlorobenzene to obtain monochlorobenzene by reacting benzene with chlorine, and the molar ratio of chlorine / benzene supplied as a raw material is 1 / 5.2 to 1 / 20.0. The present invention relates to a method for producing monochlorobenzene.

  According to the present invention, there is provided a process for producing monochlorobenzene by reacting benzene with chlorine to obtain monochlorobenzene, which has an excellent feature of obtaining monochlorobenzene from benzene in a high yield. it can.

  There is no restriction | limiting in particular about the method of obtaining monochlorobenzene by making benzene and chlorine react, A well-known method can be used. An example of a specific method is as follows. The reaction is carried out by reacting chlorine (either liquid or gas) in the benzene liquid phase. The reaction temperature is 25 to 100 ° C., and the reaction pressure may be any of reduced pressure, normal pressure, and increased pressure, but is usually normal pressure. For the reaction, iron powder, ferric chloride, iodine, aluminum chloride, antimony pentachloride, Lewis acids such as various metal chlorides, and solid acids such as zeolite and silica alumina can be used.

  In the present invention, the molar ratio of chlorine / benzene supplied as a raw material needs to be 1 / 5.2 to 1 / 20.0, preferably 1 / 5.5 to 1 / 15.0. Most preferably, it is 1 / 6.0 to 1 / 10.0. When the ratio is excessively large, benzene chlorinated substances other than chlorobenzene increase, whereas when the ratio is excessively small, the benzene reaction rate is significantly decreased.

  When benzene and chlorine are reacted, chlorinated benzenes other than monochlorobenzene are by-produced. Examples of benzene chlorinated compounds other than monochlorobenzene include 1,2-, 1,3-, or 1,4-dichlorobenzene. In the present invention, in order to obtain a high yield of monochlorobenzene obtained by reacting benzene with chlorine, the content of chlorobenzene containing monochlorobenzene in the reacted benzene is 1.0 mol% or less. preferable. If the content is excessive, the yield of monochlorobenzene obtained by the reaction is lowered. In order to make the content of the benzene chlorinated product of the reacted benzene fall within the above range when reacting benzene and chlorine, for example, a benzene chlorinated product containing unreacted benzene and monochlorobenzene obtained by reacting benzene and chlorine. When the unreacted benzene was separated by subjecting the reaction mixture of benzene to the benzene / chlorinated benzene separation step, the separated benzene was separated so that the concentration of benzene chlorinated compound containing monochlorobenzene in the benzene was 1.0 mol% or less. May be subjected to a chlorination step.

  In the present invention, a part mainly composed of benzene is separated and recovered from a reaction mixture obtained by reacting benzene and chlorine, and the part mainly composed of benzene is directly or indirectly reacted with chlorine to produce monochlorobenzene. It is preferable to recycle the raw material to obtain By doing this, when benzene and chlorine are reacted, the effect that benzene can be used effectively can be obtained even if the reaction rate of benzene is set low.

Products of the benzene chlorination reaction include hydrogen chloride produced, gaseous products mainly composed of benzene evaporated for heat removal, and liquid products. The gaseous products are the following hydrogen chloride / benzene. The liquid product is preferably sent to the following benzene / benzene chlorinated product separation step to the separation step.
Hydrogen chloride / benzene separation step: A mixture of gaseous hydrogen chloride and benzene is separated into a portion mainly containing hydrogen chloride gas and a portion mainly containing benzene, and a portion mainly containing benzene is directly or Process of recycling indirectly to chlorination process Benzene / benzene chlorinated product separation process: Process of separating benzene and benzene chlorinated product, chlorination product, and recycling benzene to chlorination process

  The gaseous product mainly consists of benzene and by-product hydrogen chloride, but may be partially condensed by cooling. The cooling temperature is preferably 6 ° C. or higher.

  The liquid product is composed of unreacted benzene and benzene chlorinated product, and may be neutralized to remove dissolved hydrogen chloride and catalyst.

  Separation of benzene and benzene chloride is performed by distillation.

  It is preferable that the hydrogen chloride and benzene components, which are gaseous products of chlorination products and are not condensed in the benzene / benzene chlorination separation step, are further sent to the hydrogen chloride / benzene separation step.

  The gaseous product can also be separated by condensing and distilling benzene under pressure.

  Benzene in hydrogen chloride can also be removed by absorption with another solvent or the like. Benzene in hydrogen chloride, and the solvent used for absorbing benzene can be adsorbed and separated by activated carbon or the like.

  The recovered benzene component can be recycled to the chlorination step directly or indirectly through the benzene / benzene chlorinated separation step.

  Monochlorobenzene obtained in the present invention can be used as a raw material for producing phenol.

Next, the present invention will be described with reference to examples.
Example 1
Monochlorobenzene was obtained by reacting benzene with chlorine. The reaction was conducted by blowing chlorine into liquid phase benzene, with a reaction temperature of 86 ° C. and a reaction pressure of 0.15 MPa. Ferric chloride was used as a catalyst for the reaction. The molar ratio of chlorine / benzene supplied as a raw material was 1 / 7.3. The content of benzene chlorinated compounds other than monochlorobenzene in the benzene chlorinated product taken out from the reaction mixture was 0.48 mol% (monochlorobenzene yield from benzene: 99.52 mol%). The flow and material balance of this example are shown in FIG.

It is an example of the flow which implements this invention.

Explanation of symbols

A Chlorination process B Monochlorobenzene / benzene separation process C Hydrogen chloride / benzene separation process 1-9 correspond to the fluid numbers in Table 1.

Claims (4)

A method for producing monochlorobenzene, which comprises reacting benzene and chlorine to obtain monochlorobenzene, wherein the molar ratio of chlorine / benzene supplied as a raw material is 1 / 5.2 to 1 / 20.0. The production method according to claim 1, wherein the content of chlorinated benzene containing monochlorobenzene in benzene chlorinated when benzene and chlorine are reacted to obtain monochlorobenzene is 1.0 mol% or less. Separation and recovery of the main part of benzene from the reaction mixture obtained by reacting benzene and chlorine, and recycling the main part of benzene directly or indirectly to the raw material to obtain monochlorobenzene by reacting with chlorine The manufacturing method according to claim 1 to be used. The production method according to claim 1, wherein the obtained monochlorobenzene is a phenol production raw material.

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