JPS5951224A - Separation of isobutylene from 4c hydrocarbon fraction - Google Patents

Abstract

PURPOSE:To separate isobutylene from a 4C fraction containing isobutylene and n-butene, by contacting the fraction with ethylene glycol countercurrently in the presence of a strongly acidic cation exchange catalyst under specific condition, thereby reacting the isobutylene with ethylene glycol. CONSTITUTION:Isobutylene is separated especially from n-butene in a 4C fraction, by contacting the 4C fraction countercurrently with ethylene glycol in the presence of a strongly acidic cation exchange catalyst having an average particle diameter of >=1mm. (e.g. styrenesulfonic acid-type cation exchange resin) at 60-120 deg.C and 5-70kg/cm<2> pressure at a liquid space velocity of the 4C fraction of 0.04-5hr<-1> keeping the molar ratio of ethylene glycol to isobutylene at >=20, thereby reacting isobutylene with ethylene glycol. EFFECT:The separation can be performed with one-step reaction in high efficiency. Since the separation can be carried out without using sulfuric acid, the corrosion of the apparatus can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for separating each component in a C4 hydrocarbon fraction (hereinafter sometimes referred to as a C4 fraction).

The C4 fraction is produced as a by-product during petroleum refining, for example, during the production of gasoline or the like by catalytic cracking of petroleum, or during the production of olefins by thermal decomposition of petroleum. This C1 fraction is generally a mixture of C4 hydrocarbons such as isobutylene, 11-butenes of 1-butene and 2-butene, and butanes.
may contain C2 hydrocarbons, C3 hydrocarbons, C5 hydrocarbons, butadiene, etc. Components such as n-butene and isobutylene separated from this C4 fraction are in increasing demand as raw materials for various materials such as secondary butyl alcohol, methyl ethyl ketone, butyl rubber, polybutene, and polyisobutylene. Isobutylene as a chemical raw material,
In many cases, n-butenes need to be purified to a high degree of purity, and the basic technology for comprehensive utilization of C4 fractions is to efficiently and industrially process each component, especially inbutylene and n-butenes. The ability to separate the two to an advantageous point is being closely examined. However, isobutylene and 1
-Butenes have almost the same vapor pressure, so it is practically impossible to separate the components in the C4 fraction by distillation alone, and unique methods other than distillation have been proposed.

Conventionally, extraction separation using sulfuric acid has been adopted as a method for separating C4 fractions, but there are problems with corrosion, requiring the use of expensive corrosion-resistant materials, and the reaction system is multi-stage and complex. However, several other separation methods have been proposed. For example, 1-butene in the C4 fraction is adsorbed and separated using crystalline aluminosilicate (Japanese Patent Publication No. 52-21481, etc.), or 1-butene in the C4 fraction is isomerized to 2-phytene and then isobutylene is separated. and distillation separation (Special Publication No. 50-22005),
A method has been proposed in which 1-butene in the C4 fraction is isomerized to 2-butene and then isobutylene is polymerized and removed (Japanese Patent Application Laid-open No. 8201/1982), but the yield and purity of the target component have been proposed. There are still unresolved problems such as insufficient strength, short catalyst life, and the inability to recover useful components by isomerization or polymerization.In recent years, isobutylene in C4 fractions has been used as a separation method for C4 fractions. Many reports have been made on separation methods in which methyl tertiary butyl ether (abbreviated as MTIIE) and tertiary butyl alcohol (abbreviated as 'l'BA) are produced as intermediate products by reacting with methanol or water. ing. However, there are several difficulties in almost completely separating and removing isobutylene from the C1 fraction.

Since the MTBE method is a homogeneous reaction, in order to remove trace amounts of imbutylene from the C4 fraction, it is necessary to repeat the reaction and separation several times to shift the equilibrium and minimize the amount of unreacted imbutylene remaining. However, the reaction system is complicated due to the multi-step process.Also, when decomposing MTBE and recovering imbutylene, losses due to dehydration and condensation of methanol cannot be ignored, and methanol and ether are mixed into the separated components, making it difficult to separate them. The problem is that it is difficult.

In the latter TBA method, water and the C4 fraction are not compatible, and in order to increase the reaction rate, it is necessary to add a polar solvent or a surfactant to the system. In this case as well, it is necessary to repeat the reaction and separation several times to shift the equilibrium and increase the conversion rate, making the reaction multistage and complicated. - Also, the polar solvent and surfactant added are difficult to separate, making the system complex. In the case of the 'l'BA method, it has also been proposed to bring water and C4 fraction into countercurrent contact in the presence of a catalyst, taking advantage of the fact that water and C4 fraction do not have a compatible structure (patent publication 56-500087).
However, in order to enhance the extraction effect and almost completely remove isobutylene from the C4 fraction, it is necessary to combine water and imbutylene. The problem is that the molar ratio and volume ratio of water must be very high and a large amount of water must be used, resulting in large heat loss. - Also, in this method, in order to reduce the residual amount of inbutylene in the C4 fraction, it is necessary to
The fraction must be cycled through the reaction region after removing the TBA contained therein, which is inefficient. In addition, this method requires the linear velocity of the raw material to be extremely high, which requires the use of a huge reaction tower with a very high height, which poses a practical problem. Furthermore, when the inventors tried this method again, the difference in specific gravity between the ascending layer and the descending layer was insufficient, and flooding was likely to occur.
Problems with operation (the ratio of the supply amount of water and C4 fraction must be changed depending on the production country of 'I' BA and the distribution ratio to each layer)
should not. ). Furthermore, in the i''BA method, TBA is difficult to separate because it azeotropes with water and is miscible with water.

As a method similar to the TBA method, it is also possible to use ethylene glycol, which behaves very similar to water, instead of water, and to remove imbutylene by reacting it with monoethylene glycol. However, this method also has the same problems as the i'BA method in the batch method and cocurrent contact method. Furthermore, since ethylene glycol behaves very similar to water, it is common knowledge that even if the C1 fraction is brought into countercurrent contact with ethylene glycol, the same problems as the TBA method will occur.

The present inventors conducted various studies and research to establish a method for separating and removing isobutylene from C4 fractions, and found that even though ethylene glycol is similar to water, C4 fractions are brought into countercurrent contact with ethylene glycol under specific conditions. Therefore, contrary to expectations, the present invention was established by discovering that isobutylene can be almost completely removed from the C4 fraction with great efficiency and industrial advantages, unlike the MTBE method and TBA method. Conventionally, ethylene glycol is thought to behave similarly to water with respect to imbutylene, so it was completely unexpected that ethylene glycol was able to solve the problem that could not be solved by the TBA method using water. Was that.

Specifically, the gist of the present invention is to process a C1 hydrocarbon fraction containing isobutylene and n-butene with ethylene glycol in the presence of a strongly acidic cation exchange catalyst having an average particle size of at least 1 nun at a temperature of 60 to 120°C. °C, pressure 5-70K
g/ajP, liquid hourly space velocity of C4 hydrocarbon fraction is 0.0
4 to 5 br-', imbutylene in the C4 hydrocarbon fraction is reacted with ethylene glycol by countercurrent contact under conditions where the molar ratio of ethylene glycol and imbutylene is 20 mol or more 1 mol or more. The present invention relates to a method for separating isobutylene from a C4 hydrocarbon fraction.

In the present invention, the etherification catalyst used in the countercurrent contact between the C4 fraction and ethylene glycol is a strongly acidic cation exchanger having an average particle size of at least about 1 m.
m or more (0 refers to particles with a particle size of about 90% or more, preferably about 95% or more), preferably with an average particle size of about 2 to 5 nun (particles with a particle size of 2 to 5 nun) It means about 9096 or more, preferably about 95% or more.

) Examples of strong acid type cation exchangers include styrene sulfonic acid type cation exchanger 11 (a sulfonated crosslinked copolymer of styrene and a polyunsaturated compound such as divinylbenzene); Phenolsulfonic acid WHIi
(On-exchange resin (condensation of phenol sulfonic acid with formaldehyde), sulfonated coal, sulfonated asphalt, sulfonic acid-type cation exchange resin (for example, Nafion manufactured by DuPont), which is made by bonding a sulfonate to a fluororesin, etc.), etc. Some have sulfonic acid groups.In order to be used for countercurrent contact in the present invention, the particle size must be large.

If particles with too small a particle size are used, it is difficult to bring them into countercurrent contact, and particles with an extremely large particle size are difficult to obtain.

The C4 fraction treated in the present invention contains inbutylene and n-butenes. If the isobutylene content in the C4 fraction is high, it is necessary to increase the amount of ethylene glycol supplied in order to almost completely remove isobutylene only by countercurrent contact. Therefore, the isobutylene-rich C4 fraction may be brought into countercurrent contact until its t, but before the countercurrent contact to substantially completely remove the isobutylene, the C4 fraction must be brought into contact with ethylene glycol, ! :i [0 to 150°C, isobutylene is reacted with ethylene glycol by contacting them in cocurrent or countercurrent in the presence of a strong acid type cation exchanger catalyst at a molar ratio of ethylene glycol and inbutylene of about 1 to 5. Depending on the method, the inbutylene content can be adjusted in advance from about 5 to 25
It is desirable to keep it as low as 100% by weight. The production reaction of glycol ether by the reaction of imbutylene in the C4 fraction with ethylene glycol by cocurrent contact is described, for example, in U.S. Pat. Nos. 2,480,940 and 31,700.
No. 00, No. 3288842, Special Publication No. 57-3568
For example, ethylene glycol and a C4 fraction are mixed in the presence of a strong acid type cation exchanger catalyst as described above at a temperature of 0 to 150°C, and the molar ratio of ethylene glycol to inbutylene is disclosed in No. 7. 0.1-100 mol 1 mol,
Liquid space velocity 0.1~100 hr-', pressure 1~70K
It consists of co-current contact mixing under the condition of y/'cm'.

The countercurrent contact of the C2 fraction with ethylene glycol according to the invention is carried out using a large particle size catalyst as described in 1 and at a temperature of about 60 to 1
20°C, particularly preferably about 70-110°C, pressure about 5-7
0 Kylon”, particularly preferably about 15 to 25 Kyl
on2, liquid space velocity of C4 fraction is about 0.04~5.0h
r-1 particularly preferably about 0.07 to 2.0 br-',
The molar ratio of the ethylene glycol supplied to the imbutylene supplied is about 207 moles or more, particularly preferably about 25 to 35 moles.
The reaction is carried out by feeding the C2 fraction from the bottom of the reaction column and the ethylene glycol from the top of the reaction column under conditions of 1 mole.

In the reaction tower, isobutylene reacts with ethylene glycol to produce ethylene glycol monotertiary butyl ether (abbreviated as MBE) and ethylene glycol di-tertiary butyl ether (abbreviated as DDE). MBE and a small amount of C4 hydrocarbons are dissolved in the ethylene glycol Jψ taken out from the bottom of the reactor, and the treated C4 fraction layer taken out from the top of the reaction tower contains almost no imbutylene, and the produced DE is dissolved. The residual isobutylene content of the treated C4 fraction is about 1% by weight or less, about 0.571% by weight or less.
It is also possible to make it less than t% or less than about 0.1% by weight.

If the reaction temperature is too low than the above range, the reaction rate will be slow and disadvantageous; if it is too high, side reactions such as olefin polymerization and DBE formation will occur, and the catalyst will be damaged. The reaction pressure must be such that the C4 fraction reaches the liquid phase, but even if the pressure is too high, the reaction system must be able to withstand high pressure, which is disadvantageous. In order to achieve this, it is necessary to make the molar ratio of the ethylene glycol to be fed and the imbutylene to be above a certain value, and to make the liquid hourly space velocity of the C4 fraction below a certain value. If the molar ratio of ethylene glycol and isobutylene is too large, the increased effect will be almost useless, and if the feed rate of each raw material is too slow, uneven flow will occur and operation will become unstable, which is disadvantageous. If the feed rate of the fraction is too fast, the efficiency of contact with the catalyst and ethylene glycol will decrease.

The C4 fraction discharged from the top of the countercurrent catalytic reaction tower contains n-butenes and has a small residual amount of isobutylene. Also, the recovery rate of n-butenes is very high, so the C4 fraction exits from the top of the countercurrent catalytic reaction tower. It can be used as a raw material for producing secondary butyl alcohol, or it can be used to separate and purify components such as 1-butene and 2-butene by distillation.

Ethylene glycol R (
Includes MBE. Dissolved C4 hydrocarbons are removed if necessary. ) is the t-t layer, or an ethylene glycol layer containing the product of reacting ethylene glycol and isobutylene in the presence of a strong acid type cation exchanger catalyst with the addition of imbutylene (it may also contain MBE and meet DBE). If necessary, dissolved C4 hydrocarbons are removed by flushing, distillation, etc.) may be obtained as an MBE gold product by (a) distillation, or (b) by addition in the presence of a strong acid type cation exchanger catalyst. It is also possible to recover isobutylene by decomposing MBE and DBE, or (c) to recover MBE and DU by heating under pressure in the presence of a strong acid type cation exchanger catalyst.
Diisobutylene may be produced by decomposing F, or
It is also possible to produce tertiary butyl alcohol by decomposing MBE + DBE by adding water and heating in the presence of a strong acid type cation exchanger catalyst. The preferred reaction conditions for obtaining imbutylene are a temperature of about 80-120°C, reduced pressure,
Particularly preferred reaction conditions for obtaining diisobutylene include pressures ranging from normal pressure to about 3 kylons and a liquid hourly space velocity of about 0.5 to 2 hr, and a temperature of about 110 to 130°C.
, pressure about 4~] OKg/11n2, liquid space velocity about 0,
2 to 1 hr-1, and the preferred reaction conditions for obtaining tertiary butyl alcohol are a temperature of about 90 to 120 °C, a pressure of 4 to 8, a molar ratio of Kylon2, a mixture of MBE and DBE, and water of about 2 to 5. Mol A, liquid space velocity of raw material approximately 0.
5 to 211 r-''. In order to obtain isobutylene and diisobutylene, a small amount of water is used during the reaction, that is, about 0.005 to 0.05 TL of water per 11 parts of the total raw materials.
Addition of the klT moiety is useful for inhibiting dehydration condensation of ethylene glycol. In the case of diisobutylene production, triisobutylene and higher oligomers are produced in very small quantities. The purity of the isobutylene thus obtained is usually 99.0% or higher, and it is possible to obtain one with a purity of 99.5% or higher. The recovery rate of ethylene glycol is also very high, for example over 99% or 99.5%.
It is also possible to set it to %.

Next, an embodiment of a method for separating a C4 fraction incorporating the method for treating a C4 fraction by self-flow contact according to the present invention will be explained with reference to a flow sheet of the drawings.

The C4 fraction from tube 1 is charged with a cation exchanger in cocurrent with the ethylene glycol-containing fraction from tube 2 (which also contains MBEXDBE, residual C4 hydrocarbons, and ethylene glycol monosecondary butyl ether). ◎The reaction product drawn out from the bottom of the reaction column 3 is introduced into the distillation column 5 through the pipe 4 to separate the C4 fraction and liquid components. do. The liquid component drawn out from the bottom of the distillation column 5 is composed of ethylene glycol, MBElr)BE, etc., and is sent through a pipe 6 to a decomposition step to be described later. The inbutylene-containing phase drawn out from the top of the distillation column is reduced to about 10 ilT mass %, and the C4 fraction is introduced into the bottom of a self-flow reaction column 8 packed with a cation exchanger catalyst through a pipe 7, and is removed from the pipe from the decomposition process described later. The recovered ethylene glycol is brought into countercurrent contact within the countercurrent reaction column 8 with the recovered ethylene glycol introduced into the top of the countercurrent reaction column 8 by 9. The C4 fraction drawn out from the top of the reaction tower 8 is
0 into the distillation column 11 to separate the C4 fraction and liquid components. The C4 fraction drawn out from the top of the distillation column 110 through the pipe 12 mainly consists of n-butene and butane, and the residual amount of inbutylene is less than 0.5 tfa%.

The components drawn out from the bottom of the distillation column 11 into the tube 13 are mainly MBE and 1) IE, and the components drawn out from the bottom of the countercurrent reaction column 8 into the tube 14 are ethylene glycol, MBE, and a dissolved C4 fraction. Together with the ethylene glycol layer, it is recycled via pipe 2 to the above-mentioned co-current reaction tower 3 as a fraction containing ethylene glycol.

The liquid component withdrawn from the bottom of the distillation column 5 consists of ethylene glycol, MT3E%DBE%, and a small amount of ethylene glycol monosecondary butyl ether, which is a reaction product with n-butene, and is passed through tube 6 to the cation exchanger. In a decomposition reaction, the monocephalic butyl ether introduced from the top of the catalyst-packed decomposition reaction tower 15 is decomposed and converted into ethylene glycol, imbutylene, and 2-butene. The product is withdrawn from the bottom of the cracking reaction column 15 and introduced via a pipe 16 into a gas-liquid separator 17, and the gaseous component withdrawn from the top of the separator 17 is separated into gas and liquid components via a pipe 18 into a compressor 19. After being liquefied at step 7, it is introduced into the distillation column 20. In the distillation column 20, impurities and n-butenes are drawn out from the bottom of the column through a pipe 21, resulting in a highly purified product with a purity of 99% or more. Inbutylene is withdrawn from the top of the column through pipe 22.

The liquid component drawn out from the bottom of the gas-liquid separator 17 is transferred to the pipe 2.
3, the ethylene glycol is introduced into the distillation column 24, where the ethylene glycol is recovered. What is drawn out from the top of the distillation column 24 is MBE that has not been decomposed in the decomposition reaction column, and is drawn out from the top of the distillation column 24.
It is recycled to the decomposition reaction tower 15. Distillation column 24
The recovered ethylene glycol is drawn out from the bottom of pipe 2.
Supply ethylene from 6 'Rikono L/! 'J (recycled through tube 9 to the top of the countercurrent reaction column 8 (reaction zone 15 may also be used for the production of diisobutylene or tertiary butyl alcohol). , fx with C4 distillate molecular water
<By countercurrent contact with ethylene glycol under specific conditions, isobutylene is selectively and efficiently removed from the C4 fraction": <Since it can be separated and removed, C4 carbonization containing only one butene and a very small amount of residual isobutylene can be achieved in one stage reaction. A hydrogen fraction is obtained, and extremely pure inbutylene, diisobutylene, tertiary butyl alcohol, and ethylene glycol monotertiary butyl ether are obtained in good yield. The recovery rate of n-butenes and ethylene glycol is also very high. In the countercurrent catalytic reaction tower, ethylene glycol monoterbutyl ether is selectively produced, and the by-products of ethylene glycol dibutyl ether and diisobutylene are extremely small.
Since BE also has a large difference in boiling point, the reaction products are separated and purified in the cylinder. In addition, in the countercurrent catalytic reaction tower, the difference in weight between the upper flow layer and the lower flow layer is about 0.05 mm, and flooding is less likely to occur, so operation is easy, unlike in the case of the TBA method.

Since the method of the present invention does not use any acid, there is no problem of corrosion as in the sulfuric acid method.

The present invention will be explained below with reference to Examples.

Example 1 A reaction tube with a cross-sectional area of about 5 arr" and a height of about 650
CC strong acid type cation exchange resin (abbreviated as OMZ) provided by Organo Co., Ltd. Copolymerized with styrene and dipinylhenzene, then sulfonated, particle size 2-5 mm
) at 75°C, 20 Ky/(B7 isobutylene synthesis plan: 20 wt% C1 fraction (composition is isobutylene 20 wt%, 1-] f y 14%, 2-
Butene 279 (1,1 saturated C4 hydrocarbon 38%, butadiene 19c1, the balance consists of other C2-5 hydrocarbons) is supplied from the lower nozzle of the reactor at a liquid hourly space velocity of 0.1 k°-
1, and ethylene glycol was fed from the upper flange of the reactor at a liquid hourly space velocity of 0.36 hr'' (molar ratio of ethylene glycol to isobutylene of 311:).

The concentration of inbutylene in the C4 fraction distilled from the upper part of the reactor is 0.3 wt, which is very similar to h1's MBE and DI.
It contained 3E. The ethylene glycol distilled from the bottom of the reactor contained approximately 5wtX MBE,
DBEFi, the distillate obtained by removing gaseous components from the top distillate at room temperature is approximately 1 of the volume of the bottom distillate.
It was wt%.

Example 2 The flow bed of ethylene glycol was changed to change the molar ratio of supplied ethylene glycol to supplied imbutylene.
111 The C4 fraction was contacted with ethylene glycol as in Example 1. When the molar ratio of ethylene glycol to isobutylene was 35.25.15 mol/mol, the inbutylene content hi of the C4 fraction distilled from the top of the reactor was 0.2, 0.6, and 1.3 wt%, respectively.

Comparative Example 1 Except that 0.36 br-' of water was supplied instead of 0.36 br-' of ethylene glycol/1II1
A reaction was carried out in the same manner as in Example 1. The combined amount of inbutylene in the C4 fraction distilled from the top of the reactor was 2.8 wt9i. Comparative Example 2 Instead of feeding 0.36 hr' of ethylene glycol from the bottom of the reaction tube, 0.36 br-1 of methanol was supplied. The C4 fraction was brought into contact with methanol in the same manner as in Example 1, except that it was fed from the top of the reactor and brought into contact with the C4 fraction in parallel flow. Isobutylene-functionalized C4 fraction distilled from the bottom of the reactor
t was 6.3 wt 9i;

Comparative Example 3 Instead of feeding ethylene glycol from the bottom of the reactor, it was fed from the top of the reactor and brought into contact with the C4 fraction in cocurrent. Contacted with ethylene glycol. The remaining amount of isobutylene for one minute of c4IrY distilled from the bottom of the reactor is 5.9wt.
%, 8'rBE, 1! : 1') +3Li: The production ratio is 20/1 wt/wt/ζ.

EXAMPLE The C4 fraction was brought into contact with ethylene glycol in the same manner as in Example 1, with the reaction temperature being 65°C. C41. distilled from the upper part of the reactor. = 7 (The amount of isobutylene used was 0.5 wt%.

Example C4 fraction was contacted with ethylene glycol in the same manner as in Example 1, except that instead of 0.36 hr" ethylene glycol, recovered ethylene glycol containing 4.5 wt% MBE as an impurity was fed. The obtained 0 results are slightly inferior to those of Example 1, and the inbutylene-containing amount of the C4 fraction distilled from the upper part of the reactor is 1. O
Example 5 The lower distillate distilled from the lower part of the countercurrent contact reaction tower obtained in Example 1 (containing 5.8 wt% MBE and 0.1 wt% ethylene glycol monosecondary butyl ether) A strong acid type cation exchange resin Amberlyst 15 (manufactured by Rohm Antonose) was used.

Copolymer of styrene and divinylbenzene & sulfonated product, exchange capacity 4.9 meq/f, particle size 0,
3-1.0? 1l) II O) Filled with 20 cc,
The reaction tube was placed at normal pressure, 110°C, and liquid hourly space velocity (LH8V).
) 0.5 hr-''.The MBE content in the distilled ethylene glycol solution was 0.75 mol%, MB
E conversion rate 76%, ethylene glycol recovery rate 98.8
The imbutylene obtained by liquefying the gaseous component separated from the distillate and then distilling it had a purity of 99% and an inbutylene recovery rate of 99.2%.

In this reaction, when 0.01 part by weight of water was added to each part of the raw material IN and the mixture was passed through a reaction tube, the ethylene glycol recovery rate was approximately 10,096.

Example 6 The reaction was carried out in the same manner as in Example 5 except that the reaction pressure was 6.3 Ky/al and the liquid hourly space velocity of all raw materials was 0.3 br-1. The isobutylene solution was separated and obtained. The MBE conversion rate was 65.9%, the ethylene glycol recovery rate was 98%, and the diisobutylene obtained after distillation purification had a purity of 99% and a yield of 86%.0 Example 7 Obtained in Example 1 The lower distillate distilled from the lower part of the countercurrent contact reaction tower was distilled under reduced pressure to recover MBE. Recovery MBE
The purity was 99.2% and the recovery rate was 98%.

Example 8 The MBE obtained in Example 7 was used as a raw material and water was mixed with MBE.
Molar ratio of l: 3.4: 1.100°C, 5.8 Ky 7
cm'', total raw material LH8V 1.21ir', was fed to a reaction tube filled with 20 cc of catalyst Amberlyst 15.The MBE conversion rate was 67%, the ethylene glycol recovery rate was 100%, and the product was A three-component azeotropic distillation operation was performed to separate and collect TBA.

Example 9 C4 fraction (composition is isobutylene 50 wt. kidney, 1-butene 25%, 2-butene 15%, saturated C4 hydrocarbon 49.5%, remainder other C2-5 hydrocarbons) according to the flow sheet shown in the drawing. ) was separated.

The catalyst packed in reaction towers 3 and 15 was Amberlyst 1.
5. The catalyst packed in the reaction column 8 was OMZ. The reaction conditions in reaction column 3 are a temperature of 70°C and a pressure of 20 Ky/a.
molar ratio of ethylene glycol to imbutylene supplied is 2.8:1, LH8V of all raw materials is 2.Ohr-'', and the reaction conditions in reaction column 8 are a temperature of 75°C and a pressure of 2.
0 Kyy6r? , a molar ratio of feed ethylene glycol to feed isobutylene of 30:1, and a cavity liquid hourly space velocity of the feed C4 fraction (containing isobutylene kt 9.1 wt X ) of 0.
．． The reaction conditions in the reaction column 15 were a temperature of 110° C., normal pressure, and a liquid hourly space velocity of all raw materials of 1.Oht. The inbutylene content of the C4 fraction distilled from the top of the distillation column 11 is 0.3 wt:%, the n-butene recovery rate is 94%, and the imbutylene distilled from the top of the distillation column 20 is pure. i99.6%, recovery rate was 99.3%.

[Brief explanation of drawings]

The drawing is a flow sheet showing one embodiment of the method of the present invention.

Claims (1)

[Claims] A C4 hydrocarbon fraction containing isobutylene and n-butene is mixed with ethylene glycol and has an average particle size of at least IR.
Temperature 6 in the presence of a strong acid type cation exchanger catalyst of 170 or higher
0~120℃, pressure 5~70 Ky/cn? , C4
The liquid hourly space velocity of the hydrocarbon fraction is 0.04 to 5 hr', and the molar ratio of ethylene glycol to inbutylene is 20 mol 1
C by countercurrent contact under conditions of more than molar
1. A method for separating isobutylene from a C4 hydrocarbon fraction, characterized in that inbutylene in the C4 hydrocarbon fraction is separated by reacting with ethylene glycol.