JPS60252434A - Production of allyl chloride - Google Patents

Abstract

PURPOSE:To obtain the titled compound economically, from a gaseous reaction product produced by the high-temperature reaction of propylene with chlorine, by using an apparatus for cooling the gaseous reaction product to a specific temperature wherein the inner surface of the apparatus is made of nickel or a particular nickel alloy. CONSTITUTION:Propylene 1 is made to react (18) with chlorine 2 at high temperature, and the produced gaseous reaction product 3 is separated into unreacted propylen, by-produced hydrogen chloride 13, light fraction 17, heavy residue 16 and allyl chloride 14 by cooling (19, 20, 22). In the above process, at least the inner surface of te apparatus 19 to cool said gaseous reaction product 3 to 300-150 deg.C is constructed with a material made of nickel or a nickel alloy having a nickel content of >=30wt%, preferably >=45wt%. The deposition of polychlorides, tar, carbon, etc. which unables the continuous operation of the apparatus 19 can be prevented, and the allyl chloride 14 can be recovered economically and efficiently from the gaseous reaction product 3.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing allyl chloride. More specifically, the present invention relates to a method for economically and efficiently recovering allyl chloride from a reaction product produced by reacting propylene and chlorine at high temperatures.

Conventionally, allyl chloride was produced by reacting propylene and chlorine at high temperatures, and cooling the reaction product using a heat exchanger.
This is carried out by a method in which allyl chloride is recovered by rapid cooling and fractional distillation of the cooled fraction (for example, Japanese Patent Publication No. 40-28177).

[7] However, in method 1, it is difficult to cool properly before quenching, and as a result, polychlorides, tar, carbon, etc. accumulate in the heat exchanger, clogging the heat exchanger and making continuous operation impossible. As a method to improve this disadvantage, when propylene and chlorine are reacted at high temperature and the reaction product is quenched, the reaction product is treated as part of the low-temperature gas taken out from the quenching bath. A method has been proposed in which a mixed gas of 180 to 250"C is mixed with 180 to 250" C and introduced into a quenching bath (Japanese Patent Publication No. 80250/1983).

This method significantly improves the deposition of tar, carbon, etc. inside the piping compared to the above method, but it cannot completely prevent the deposition of tar, carbon, etc. in the area where the reaction product and low-temperature gas are mixed. If the preventable mixing of reaction products and low-temperature gas is disrupted, long-term continuous operation may become impossible.

In view of these circumstances, the inventors of the present invention have conducted extensive studies to establish a process that does not cause the deposition of polychlorides, tar, carbon, etc. on heat exchangers, piping, etc. as described above.
The deposition of the polychlorides, tar, carbon, etc. mentioned above occurs significantly when the reaction product comes into contact with iron-containing materials in the area where it is cooled to a temperature of approximately 300 to 150°C, and the deposition is We have completed the present invention by discovering that this is unlikely to occur on the material surface of Sokel.

That is, the present invention is a process of cooling the gaseous reaction product produced by reacting propylene and chlorine at high temperature and separating it into unreacted propylene, by-product hydrogen chloride, light fraction, heavy residue, and allyl chloride. In the method for producing allyl chloride consisting of at least about 8
Allyl chloride characterized in that the inner surface of the device to be cooled to 00 to 150°C is made of a member made by Nickel Jizkin, which has a Nickel content of 30% by weight or more. This is a manufacturing method that substantially eliminates the deposition of polychlorinated substances, tar, carbon, etc. on heat exchangers, piping, etc.

The method of the present invention will be explained in detail below.

In carrying out the method of the present invention, propylene and chlorine are approximately 45%
The reaction is carried out in a temperature range of 0 to 510°C.

The reaction products are the main component allyl chloride, unreacted propylene, by-product hydrogen chloride, some polychlorinated substances, tar,
Contains carbon, etc.

These reaction product gases are sent to a mixing zone with cold gas removed from a heat exchanger or quench bath.

In carrying out the method of the present invention, the reaction product is about 300 to 15
It is usually this heat exchanger or mixing zone that is cooled to 0°C, and the present invention provides that the inner surface of this part of the device is made of nickel or a 2...l Kel alloy with a nickel content of 30% by weight or more. Such Ni-Kel or Ni-Sokel alloys, such as Honeykel, Hein-Conel, Incoloy, Hastelloy alloys, etc., have a nickel content of 30% by weight or more, preferably 45% by weight.
The above nickel alloys can be mentioned.

Although it is unclear why the use of nickel or nickel alloy effectively eliminates the deposition of polychlorides, tar, carbon, etc. on heat exchangers, piping, etc., When the material of the cooling device is an iron-based material, a specific component in the reaction product turns into tar on the surface of the iron material, or a tar component in the reaction product is highly compatible with the surface of the iron material. As a result, the gaseous reaction products are cooled and polychlorinated substances, tar, etc. that precipitate are deposited on the inner surface of the equipment.On the other hand, in the case of nickel-based materials, they are not compatible due to their corrosion resistance. This is thought to be because the deposition of polychlorinated substances, tar, carbon, etc. can be substantially eliminated as a result.

The inner surface of the device, in which the reaction product is cooled to about 300 to 150°C, is made of a 2'Y Kel or 2.1 Kel alloy member because the reaction product that occurs under normal allyl chloride synthesis reaction conditions is Since polychlorides and tar generally precipitate at temperatures of about 80°C to 150°C, at least the part where this precipitation starts is made of a 2-Sokel alloy that does not cause 21-king to prevent kneading.1. / is there.

As a means of constructing the inner surface of the device with a member made of nickel or a nickel alloy, the entire device may be made of Ni-Sokel or 2+7 Kel alloy, or the inner surface of the device may be clad with Ni-I-Kel or Ni-Sokel alloy. ]7. Formation may be avoided.

Of course, constructing the inner surface of the device from the part where propylene and C12 are reacted at 450 to 510°C to the part where it is cooled to about aoo to 150°C with nickel or nickel alloy members means that polychlorides, tar, etc. In carrying out the process of the present invention, which may have the effect of reducing carbon, the gaseous reaction products from the reactor are introduced into a heat recovery device, preferably made of 2, Sogal or nickel alloy, and heated at a temperature of about 4.50° to 510°. The energy recovery method for recovering the energy of the reaction product gas of C up to 150 to 250°C is to directly heat water with the reaction product gas and recover it as steam, or to use a heating medium such as Dowsum or a raw material of allyl chloride. In carrying out the method of the present invention, a method such as heating a certain propylene and recovering it is generally adopted. Precooling, generally about 150-250
The reaction product gas cooled to 'C is then sent to a quenching facility for complete and substantially complete precipitation of tar.

The quenching equipment may be either a line quencher or a pit type.

The reaction product is generally cooled to about 70-50°C in the quenching facility to effectively remove tar.

When using a line quencher, a storage tank is provided after the line quencher, and part of the cooled reaction product is used to supply the line quencher, and unused water from the gas phase of the storage tank is The reacted propylene, by-product hydrogen chloride, low boiling point components and allyl chloride are separated as appropriate. On the other hand, a portion of the cooling liquid is appropriately extracted and sent to a concentrator, and the evaporated fraction is recycled to a storage tank.On the other hand, the residue consisting of tar, carbon, etc. is taken out of the system and disposed of.

By adopting the method of the present invention as detailed above, in the case of the conventional method, the heat exchanger had to be cleaned every 1 to 2 months, but with the method of the present invention, the heat exchanger can be operated continuously for about 1 year. Significant industrial benefits can be achieved by making it possible to

EXAMPLES In order to explain the method of the present invention in further detail, it will be explained based on examples.

Example 1 This will be explained based on FIG.

Propylene 1.2 B mol/H from line 1.

Chlorine 0.82 mo IIH (CB/Ct
2=4 molar ratio) is continuously fed to a thermal chlorination reactor 18 maintained at about 480-500°C. The gaseous reaction product from the thermal chlorination reactor 18 is sent via line 8 to a heat exchanger 19 having nickel tubes and cooled to about 200'C. Boiler feed water is sent to the heat exchanger 19 through line 4, and is taken out as steam from line 5 and used.

The precooled reaction product from the heat exchanger 19 passes through line 8, is pressurized by a pump, and is rapidly cooled by 400 kg/h of cooled reaction product supplied from line 9.

Line 6 and line quencher 20 were made of Inconel.

The reaction product is cooled to 60"C by the ink quencher 20 and sent to the storage tank 21 through a line.

The gas phase in the storage tank 21 mainly consists of allyl chloride, unreacted propylene, by-product hydrogen chloride, and some polychlorinated substances. The condensate is then recirculated. Uncondensed unreacted −j
a Hirene, by-product hydrogen chloride, and allyl chloride are sent to the distillation column 23 via line 12, and from the top of the column, by-product hydrogen chloride,
Unreacted propylene is taken out through line 18, and allyl chloride is taken out from the bottom of the column through line 14 at 21~/H.

Unreacted propylene is separated from by-product hydrogen chloride and recycled as a raw material for the chlorination reaction. The allyl chloride recovered from the mataline 14 is further purified by distillation, if necessary.

On the other hand, the cooled reaction product from the bottom of the storage tank 21 is sent to the concentrating tank 24 via the line 15, heated by a steam heater, and concentrated heavy components such as polychlorinated substances, tar, and carbon are sent to the concentrating tank 24 through the line 15. 16 to be disposed of outside the system at a rate of 8 Kg/Hr. The low boiling point fraction from the concentrator is line 17.
It is then recirculated to the storage tank 21.

As a result of continuous operation for 8 months under the above conditions, the amount of tar-like deposits in the heat exchanger was as shown in Table 1, Experiment No. 1.

In addition, the above method was operated in exactly the same manner except that the materials shown in Table 1 were used for the heat exchanger. The results are shown in Table 1.

Table 1 Table 1, 1: Approximately 3
Equipment for cooling part to 00 to 150°C tfji
It is clear that when using a 2-Sokel alloy containing 2+7 Kel or 2-Nogal with a maoi nail percentage of E or more, the formation of deposits can be significantly reduced and continuous operation can be achieved for a long period of time. Ru,

[Brief explanation of the drawing]

Figure Fg 1 is a process diagram for producing allyl chloride according to the method of the present invention. Summer, 2.3.4.5.6.7.8.9.1o, 11.1
2.13.14.15.16 and 17... Conduit 18... Thermal chlorination reactor 19, Heat exchanger 20, Line quencher 21. ... Storage tank 22 ... Condenser 28 ... Distillation column 24 ... Concentration pot collection 1 throat 1

Claims (1)

[Claims] 1) Consists of cooling the gaseous reaction products produced by reacting propylene and chlorine at high temperatures and separating them into unreacted propylene, by-product hydrogen chloride, light fractions, heavy residues, and allyl chloride. In the method for producing allyl chloride, at least the gaseous reaction product has a molecular weight of about 300 to
2) A method for producing allyl chloride, characterized in that the inner surface of the apparatus to be cooled to 150°C is made of a member made of Ni-Sokel or a nickel alloy having a nickel content of 30% by weight or more. The inner surface of the device, which is cooled to about 800-150°C, is coated with nickel or nickel content 4.
The method for producing allyl chloride according to claim 1, characterized in that the member is made of a di-soquel alloy containing 5% by weight or more.