JPS6058932A - Production of methyl-t-butyl ether - Google Patents

Abstract

PURPOSE:To produce the titled compound useful as an antiknocking agent, continuously, by reacting isobutylene with methanol in an adiabatic reactor, introducing the obtained reaction mixture to a reactive distillation column, and reacting the unreacted raw material in the column while separating the titled compound from the mixture. CONSTITUTION:Methyl-t-butyl ether is produced by reacting isobutylene with methanol in the presence of a solid acid catalyst. The raw material mixture is introduced through the line 1 into the adiabatic reactor 3 filled with the catalyst 2, and the reaction mixture is taken out through the bottom of the reactor and supplied to the distillation column 5. The objective compound is recovered from the bottom of the column 5. The unreacted isobutylene and methanol are transferred to the reaction zone 9, and the reaction product is returned to the top of the distillation column 5 to recover the product. EFFECT:An isobutylene conversion of as high as >=99% can be achieved by using a simple and compact apparatus.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides methyl-t-butyl ether (hereinafter sinnm
``+-Lat%4%4111.'n7J, Iy-L+
The present invention relates to a method for continuously producing MTBE from rL [C-br sweetened with l+-] and methanol.

MTBE is produced in large quantities in Europe and America as an octane number improver for gasoline.

In addition, JMTBE is decomposed to produce imbutylene and methanol with high purity and easy to obtain.
Since BE can be obtained in high purity from C4 distillate containing impurities other than inbutylene, the manufacturing method for MT'BE is C4.
It is also important as a method for separating isobutylene from distillates. It is also important as a raw material for producing t1-butene-1 and butadiene, a C4 fraction that does not substantially contain imbutylene, which is the residue obtained by reacting almost the entire amount of inbutylene.

By the way, there is a method for producing MTBE by reacting inbutylene and methanol in the presence of a strongly acidic ion exchange resin, and a method for producing MTBE by reacting a tertiary olefin and a primary alcohol in the presence of an acidic ion exchange resin. As a method for producing class ether, for example, Japanese Patent Application Laid-Open No. 51-6912
No. 1, Japanese Patent Publication No. 52-20965, and Japanese Patent Application Laid-Open No. 1973
Publication No. 3-7607tt Rabbi mUsP4, 198.5
! 10 and the like are known.

In these methods, the etherification reaction and the distillation to separate MTBE are carried out separately, and the etherification reaction product contains MTBE, methanol, imbutylene, and other accompanying hydrocarbons. It is sent to a distillation process for separation, where the product MTBE is separated and obtained.

However, in the method of Toh et al., it is necessary to achieve a high reaction rate of inbutylene in the reaction step, and if a large amount of methanol is used for this purpose, there will be a large amount of unreacted methanol.
This method has the drawback that the separation process requires a heavy burden, such as requiring distillation at high pressure.

By the way, since the etherification reaction is an equilibrium reaction,
If the reaction temperature is high, the reaction will be rapid, but on the other hand, the reaction rate will not increase. Although the inbutylene reaction rate can be increased by increasing the amount of methanol, it becomes difficult to distill off methanol as an azeotrope to the C4 fraction in the distillation process and separate it from MTBE. Also, since this reaction is exothermic, a strong exothermic rise occurs in the catalyst layer, which has poor heat conduction, but this causes deterioration of the catalyst, so to avoid this deterioration, a multi-tubular reactor is used. Measures are taken to keep the temperature of the catalyst layer low, such as by recycling the reaction product liquid to dilute the raw material liquid and lowering the temperature at the inlet of the catalyst layer. However, under these conditions, the reaction rate becomes low, so the space-time yield of MTBE 1t (ST Y kyMTB
E/7! catalyst, hr) is lower, therefore a larger amount of catalyst is required and the reactor must be larger.

In addition, a C4 fraction that does not substantially contain isobutylene is industrially useful, but in order to obtain such a C4 fraction, the reaction rate of inbutylene is required to be 99% or more. To satisfy this requirement, there is an equilibrium wall, so the reaction and distillation steps must be repeated two or more times.

In order to advance the reaction advantageously in equilibrium and increase the reaction rate, methanol and imbutylene are reacted in the reaction zone of the reactive distillation column, and the obtained MTBE is successively extracted from the reaction system by distillation from the reaction liquid. There is a so-called reactive distillation method that extracts the

Examples of this format include USP 5634534, U
It is described in SP 4307254 and USP 4336407. In these cases, the reaction and distillation are carried out simultaneously, so only one step is required, but these conventional methods have their own major drawbacks and have not yet been put to practical use.

In other words, (1) the reflux ratio must be set high because the distillation balance is disrupted by the heat of reaction, and (2) if methanol is significantly excessive relative to imbutylene, a large amount of methanol will be mixed into MTBE, and in order to remove this methanol by distillation, it is necessary to I have to reduce the pressure ψIII! g+deke1
1. When the amount of methanol used is reduced, diisobutylene is more likely to be produced as a by-product. (2) Since the reaction solution is largely diluted with the reflux solution, the reaction rate is slow, and in order to obtain a high reaction rate, the reaction zone must have a large capacity.

There were drawbacks such as.

The present inventors took advantage of the fact that the reaction rate of imbutylene in the reactive distillation method can be increased and that distillation can be carried out simultaneously with the reaction, while overcoming the above-mentioned drawbacks of the reactive distillation method. The present invention was developed as a result of intensive research aimed at creating a process that can achieve an inbutylene reaction rate of 99% or more using a simple and compact device.

That is, the present invention reacts imbutylene and methanol in the presence of a solid acid catalyst to produce methyl-t-methylx-
−? In the method of passing a mixture of imbutylene and methanol through an adiabatic reactor, imbutylene and methanol are reacted to produce at least methyl-
A reaction product containing butyl ether and unreacted imbutylene and methanol is obtained, and the reaction product is subsequently introduced into a reactive distillation column in which unreacted imbutylene and methanol are reacted and methyl-t This is a method for producing methyl-1-butyl ether, which is characterized by separating -butyl ether.

The undyed imbutylene used in the present invention may be imbutylene itself or a hydrocarbon containing imbutylene. In particular, C after naphtha cranking
The so-called spent BB after extraction of butadiene from the 4th fraction.

C4 fractions from catalytic cracking, butane dehydrogenation products, isobutane pyrolysis products, and the like are industrially suitable.

The concentration of inbutylene in the raw material hydrocarbon is usually 2 to 6.
0wt96.10-60wt96 is preferable.

The amount of methanol used is usually 0.8 mol or more, preferably 0.8 to 1 mol, per 1 mol of isobutylene.
10 mol, preferred for erections tlo.

The ratio is 95 to 5 moles. Note that when the inbutylene astringency of the raw material hydrocarbon is low, such as less than 5 wi96 , the amount of methanol used can be increased. Also, for example, 1vi T B for adding gasoline
The production of diisobutylene is evaluated as in the case of E production.
and/or when you want to reduce the amount of unreacted methanol in the reactive distillation column distillate and thereby omit the methanol recovery step, use methanol 1 to 1 mole of imbutylene. whereas normally it is 1.05
The amount is less than 1 mol, preferably 0.8 to 1 mol, particularly preferably 0.95 to 1 mol. Incidentally, imbutylene and methanol may be supplied to the adiabatic reactor as a mixture thereof, or may be separately supplied to the adiabatic reactor and mixed within the reactor.

Although there are no particular restrictions on the type of the first stage thermal reactor, a piston flow reactor is usually used. The reaction conditions of the adiabatic reactor are that the catalyst layer inlet temperature is usually 40 to 80°C, preferably 50 to 70°C, and the catalyst layer inlet temperature is higher than the catalyst layer inlet temperature, usually 60 to 90°C, preferably 7
The temperature is 0 to 85°C. In order to maintain the catalyst bed temperature at such a temperature, the pressure at the top of the reaction distillation column is usually set at 5 to 12
kg 7 am 2 G can be divided into m sections.

As the catalyst in the adiabatic reactor, a solid acid catalyst is used, and for example, a macroporous strongly acidic ion exchange resin, a solid phosphoric acid catalyst, and zeolite are used. Among these, macroporous strongly acidic ion exchange resins are preferred.

Representative examples of macroporous strongly acidic ion exchange resins include Amberlyst 15 and Amberlyte 200C (
For both names, 0.01 to 0.2 times that of Rohm & is appropriate.

In the first stage adiabatic reactor, the inbutylene reaction rate is 80-9
3%, which is the reaction rate of the conventional cooling reactor9
It is low compared to 5-9796.

However, this reaction rate is achieved in a very short time in an adiabatic reactor. Therefore, the reaction product liquid which has a relatively low reaction rate and contains a relatively large amount of unreacted methanol and imbutylene which comes out of the first stage adiabatic reactor is directly supplied to the reactive distillation column. Since unreacted imbutylene and methanol are separated from MTBE together with the hydrocarbons accompanying the imbutylene, a high imbutylene reaction rate can be obtained.

In the reactive distillation of the present invention, the concentration of imbutylene in the distillation column P is suppressed to a low level, and even if the methanol/imbutylene molar ratio at the inlet of the adiabatic reactor is made slightly excessive, , ii, it is possible to suppress the amount of inbutylene in the column.

In addition, since methanol is removed in the reactive distillation column, it is possible to operate at a lower pressure than in the case of a normal distillation column in which unreacted methanol is co-distilled by pressure distillation. It becomes possible. The reaction rate of isobutylene in an adiabatic reactor is generally considered to be 80-93%, so in order to achieve a total reaction rate of 99%, the reaction rate of isobutylene in the reactive distillation column must be 85-9596. Often, this will reduce the load on the reaction zone in the reactive distillation column by a large I+ and therefore require a smaller amount of catalyst to be retained in the reaction zone. Therefore, the efficiency of distillation increases, and the column becomes more compact.

In a reactive distillation column, the reaction zone is provided in a portion corresponding to the upper stage of the column, but the reaction zone may be provided within the distillation column.
It may also be provided separately from the distillation column.

The number of stages in the reactive distillation column, the supply stage, the position of the reaction zone, the reflux ratio, etc. vary depending on the composition of the reaction product liquid from the first stage adiabatic reactor, the reaction conditions in the reactive distillation vessel, the distillation conditions, etc. Although it cannot be specified, the required number of stages is usually 15 to 40 stages. The number of supply stages is preferably a middle stage of the distillation column or a stage slightly below the middle stage. The reaction zone is located above the supply stage, and the interval between the two is set to 6 to 5 distillation stages. Also, the smaller the reflux ratio, the better.
It is usually 0.3 to 10, preferably 0.5 to 5. As mentioned above, the pressure inside the reaction distillation column is usually 5 to 5.
12kl? / cm2 G, if preferably 8-
10k! ? / cm2 G.

The type of catalyst used in the reaction zone of the reactive distillation column is the same as that used in the first stage adiabatic reactor. Also, the amount of catalyst used in this reaction zone need not be greater than the volume of catalyst used in the adiabatic reactor;
The volume 117 is less than the same volume, preferably about 0.2 to 0.8 times.

There are no particular restrictions on the method of installing the catalyst in the reaction zone of the reactive distillation column, but for example, USP 3 (534
534, in which the catalyst is installed on the downcomer, or as in USP 4307254, a fabric belt with a pocket containing ion exchange resin is supported with a wire mesh and placed on a shelf, or a catalyst is placed on a shallow shelf. There are things that create layers. The conventional diameter of the catalyst is 0.5
In addition to ~2mm granular particles, 111 has excellent distillation ability and reaction speed to
Being able to reduce j is of great industrial significance since Mi< should.

The following is an example of the present invention, but the present invention is not limited thereto.

Example 1 As a raw material containing y-y-y-lene, the so-called spen after extracting butadiene had a measurement value of 4596.

The adiabatic reactor has an inner diameter of 59.4 mm and a length of 2. It is made of IWL stainless steel tube and has a thermometer sheath tube and perforated plate inside.

Using commercially available Amberly) 20DC as a macroporous strongly acidic ion exchange resin catalyst, this ion exchange
Ji)r': l It was pre-swollen to %411 with methanol and filled as a catalyst.

The reactive distillation column was a plate column with an inner diameter of 102 m+iψ and a height of 4.5 rr, corresponding to 22 theoretical plates. The reaction product liquid from the adiabatic reactor was supplied to a portion corresponding to the 11th stage of the reactive distillation column. In the catalyst filling stage, a catalyst is placed between the upper and lower sides of a 50-mesh wire mesh in a sandwich-like manner, and the reflux liquid from the downcomer in the upper stage passes through this catalyst layer and is combined with the steam from the lower stage. contact within the catalyst layer. The catalyst filling area was a portion corresponding to the 15th to 19th stages, and the total length of the catalyst layer was 1.2 m. The catalyst was Amberlite 200C, which was the same as in the adiabatic reactor, and the reactor was charged with methanol at 91 rN at the earliest stage.

Raw material Sven) Add methanol to the isobutylene in BB at a molar ratio of 1.1 times, and after mixing, add 26 kl of methanol under pressure to a liquid state using a metering pump. /hr into the adiabatic reactor. The catalyst layer inlet temperature of the adiabatic reactor is 55
regulated at °C. The reaction pressure is the distillation column top pressure 7,
#fI by adjusting to 5 kg/cm2 G
The inlet of the thermal reactor was 8 to 9/σ2G. The catalyst layer outlet temperature of the adiabatic reactor was 81°C. The reaction product liquid from the adiabatic reactor was directly supplied to the reactive distillation column. The composition at the outlet of the adiabatic reactor is shown in Table 1. The inbutylene reaction rate at this time was 8,996.

The reactive distillation column is operated at a reflux ratio of 2.0, and the distillate (71°C
) and the bottoms liquid (145°C) are shown in Table 1.

The reaction rate in the reactive distillation column was 9,696, and the total reaction rate was 9,996. Also, the total MjBESTY is 2,
It was 4 kgMTB E/J-c, atlr.

Table 1 Inbutylene 35.1 3.9 0.55 Methanol 22.0 4.5 4.2 MTBE 48.5 99
．． 1 + Other C442,9421,995,20,2 Diisobutylene 0,15 0,3 t-Butanol 0.20 0.4 Stream 1 (kI7/hr) 26,0 26.0 11. 6
14.4 Total Butanes and Butenes Example 2 As the raw material containing inbutylene, the 704 fraction obtained from the fluid contacting and decomposition process was used.

The concentration of inbutylene in this fraction was 1,696.

Using this raw material, M TBE was produced according to the process shown by the flow sheet of the first example. In this process, a distillation column and a reaction zone are provided separately, and the reaction zone uses a reactive distillation column connected to the top of the distillation column.

That is, in FIG. 1, a mixture of the raw material C4 fraction containing inbutylene and methanol is supplied to the adiabatic reactor 6 filled with the catalyst 2 through the raw material supply pipe 1 as well. ! A reaction product liquid containing unreacted imbutylene and methanol is discharged from the bottom of the thermal antithermal reactor and sent to the distillation column 5 via channel 4.
(Supplied from the distillation column 5 through the bottoms pipe 6 (M
The bottoms containing TBE is drawn off. Distillation column 5
From the top of the column, unreacted imbutylene and sludge containing methanol and ashing water other than imbutylene are discharged. This gas is sent via line 7 to reactor line 79, which is filled with catalyst 8. The >+ T HE produced in reaction zone 9 is contained in the reaction zone effluent, and this reaction zone UP effluent is sent by pump 10 to the i+ top of distillation column 5. Anti-Luci, top B1 of zone 9≦
The sludge discharged from υ is sent to the condenser 121 via the flow path 11 and returned to the reaction zone 9 via the flow path 13, and the remainder is discharged from the system through the flow path 14 as a distillate.

Further, the non-condensed content in the condenser 12 is discharged to the outside of the system via the pressure regulating valve 15 as bottom gas.

The adiabatic reactor 6, the catalyst 2 filled therein, the reaction conditions, etc. were the same as in Example 1.

The distillation column 5 is a tray column with an inner diameter of 10 m111 ψ and a height of 4 m, which corresponds to 20 theoretical plates. The reaction zone 9 connected to the top of the distillation column is a packed column with an inner diameter of 208 mm and a height of 1.4 WL, which corresponds to four stages at the top of the distillation column.

Dixon banking and Amberlite 200'G were dispersed inside the reaction zone.

Amberlite 200-G was used after being swollen to 31 with methanol.

In order to prevent the catalyst from falling off, a C50 mesh wire gauze was used as the lower support. A mixed solution prepared by adding methanol to isobutylene in the raw material at a molar ratio of 1.3 times was supplied in liquid form under pressure to the adiabatic reactor B at a rate of 50 kg/hr using a constant pump, and the tower top pressure (reaction zone outlet pressure ) for 10k
By adjusting the inlet pressure of the adiabatic reactor B to 9/α2G to 10.5, the above catalyst layer temperature was maintained. The reaction product liquid in the adiabatic reactor was directly supplied to a portion corresponding to the 14th stage of the distillation column. The inbutylene conversion rate at the outlet of the adiabatic reactor was 84%. The reactive distillation column was operated at a reflux ratio of 1.5, with a top temperature of 76°C and a bottom temperature of 154°C. The reaction rate in the reaction zone of the reaction vapor column reached 96%, and the inbunalene conversion rate was 99.4%.

The composition of each step is shown in Table 2.

Table 2 Inbutylene 14.3 2.2 0.11 Methanol 10.6 3,7 3.1 MTBE 18.9 99
．． 0 + Other C475,175,196,80,43 diisobutylene 0.06 0. Filter 1 t-butanol 0.
05 0. 26 Flow rate (ky/hr) so, o so
, 0 23. 3 6. 7 U.S. Total of butane squares and butenes

[Brief explanation of drawings]

FIG. 1 is a flow sheet of the process used in Example 2. In the drawing: 1 Raw material supply pipe 2 Catalyst 3 t! ili thermal reactor 5
Distillation column 6 Bottoms pipe 8 Catalyst 9 Reaction zone 10 Pump

Claims (1)

[Claims] In a method for producing methyl-1-butyl ether by reacting imbutylene and methanol in the presence of a solid acid catalyst W, a mixture of isobutylene and methanol is heated to
2 reactors to react imbutylene and methanol to obtain a reaction product containing at least methyl-[-butyl ether and unreacted imbutylene and methanol, and then the reaction product is passed through a reactive distillation column. A method for producing methyl-1-butyl ether, which comprises reacting unreacted imbutylene with methanol and separating methyl-1-butyl ether.