JPS58144336A - Production of glycol mono-tertiary-alkyl ether - Google Patents

Abstract

PURPOSE:The reaction between a dialkyl ether containing tert.-alkyl groups or an iso-olefin and a glycol is carried out in the presence of a strongly acidic ion exchange resin, the reaction mixture is brought into contact with a basic ion exchange resin and distilled to give the titled substance. CONSTITUTION:The reaction between a dialkyl ether containing tert.-alkyl groups such as methyl tert.-butyl ether or an iso-olefin such as isobutene and a glycol is carried out at a molar ratio of 1/(5-10) in the presence of a strongly acidic ion exchange resin at 60-90 deg.C for 0.25-2hr to prepare the titled substance. Then, the reaction mixture is brought into contact with a basic ion exchange resin such as quaternary ammonium type resin at room temperature to 100 deg.C to remove the eluting acids, then the product is distilled. The glycol recovered as the bottom fraction in the above distillation can be circulated as a starting material without purification.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing glycol monotertiary alkyl ethers.

A method for producing glycol monotertiary alkyl ether (hereinafter sometimes abbreviated as GMTE) by reacting a glycol with an isoolefin in the presence of a strongly acidic ion exchange resin is already known. In this reaction, acidic substances are eluted from the ion exchange resin into the reaction mixture, causing undesirable decomposition of ()MTE during the separation and acquisition process of the target product GMTE, resulting in a decrease in the yield and quality of GMTE. It is also known to cause

In order to improve this drawback, the reaction mixture is treated with a solid basic substance such as 7.idrotalcite or magnesium oxide (Japanese Patent Application Laid-open No. 53-65809), or with iron, iron oxide, iron hydroxide, etc. Method of
Methods such as No. 1) have been proposed, and have achieved some success.

By the way, in the OMTF and the reaction mixture, ()MT
In addition to E, a large amount of unreacted glycol is contained, and when GMTE is separated by distillation from the reaction mixture, glyfur is obtained as a bottom fraction. It would be industrially advantageous if a large amount of glycol obtained as a bottom fraction could be reused as is in the original reaction, but it is possible to extract a large amount of glycol from a bottom fraction from a reaction mixture that has been treated as proposed above. If Glyfur obtained as a glycol is reused as it is, a part of the processing agent will be dissolved or suspended in the glycol, poisoning the strongly acidic cation exchange resin that is the catalyst, and causing damage over time. It was found that the catalyst performance was reduced. For this reason, when adopting the latter proposal, it has been proposed to separate the ethylene glyfur in the bottom fraction by distillation and reuse it after removing the residual iron with a processing agent (Unexamined Japanese Patent Publication No. No. 56-103127), an extra distillation operation was required, and the inventors had already used Ll instead of isoolefin.
Japanese Patent Application No. 55-17 concerning a similar production method of GMTg using a dialkyl ether having one E-class alkyl group
Although this proposal was proposed in No. 3193, it was found that this proposal also had the same problems as mentioned above. Therefore, the present inventors conducted intensive studies to overcome the above-mentioned drawbacks and difficulties during the production of GMTE, and as a result, they were able to effectively remove the acid eluted from the strongly acidic cation exchange resin, and to improve the production of GMTE in the post-treatment process. We have discovered an economically advantageous improvement method that suppresses the decomposition of glycol and allows the recycled glycol to be used without purification. That is, according to the present invention, (A) a tertiary alkylating agent selected from the group consisting of dialkyl ethers having one tertiary alkyl group and isoolefins is reacted with a glycol in the presence of a strongly acidic ion exchange resin. (13) A step of contacting the reaction mixture with a basic ion exchange resin prior to distillation separation of GMTE, (C
) distilling and separating GMTE from the contact-treated reaction mixture; (D) recycling the glycol recovered as the bottom fraction of step (C) to step (A). A manufacturing method is provided.

The dialkyl ether having one tertiary alkyl group that can be used as one of the raw materials of the present invention is
(In the formula, R is a tertiary alkyl group, R1 is a primary or secondary
an alkyl group). In the above formula, R includes unsubstituted tertiary alkyl groups such as tertiary butyl, tertiary pentyl, tertiary hexyl, tertiary hebutyl, and tertiary octyl, and phenylisopropyl groups. These include an alkyl group substituted with an aryl group. Also R1
Primary alkyl groups such as methyl, ethyl, propyl, n-butyl, n-pentyl, n-octyl, or 1so
-propyl, 5eC-butyl and other secondary argyl groups. R1 preferably has a small number of carbon atoms, most preferably one having 1 to 3 carbon atoms. More specifically, methyl tert-butyl ether, ethyl tert-butyl ether, n-propyl tert-butyl ether,
Typical examples include 1so-propyl tertiary butyl ether, tenopemethyl tertiary pentyl ether, and ethyl tertiary pentyl ether.

In addition, inolefins that can be used as one of the raw materials include isobutyne, inamylene, 2-methyl-
Examples include 1-pentene and 2-methyl-1-hexene. Among these, it is particularly preferable to use isobutine.

Glyfur reacted with the above-mentioned tertiary alkylating agent is represented by HOROH (wherein R is a divalent hydrocarbon group). R2 is, for example, a divalent hydrocarbon group such as ethylene, trimethylene, 1,2-propylene, tetramethylene, hexamethylene, octamethylene, ethyleneoxyethylene, ethylenedi(oxyethylene), or ethylenetri(oxyethylene). . More specifically, ethylene glycol, propylene glycol, 1.
4-butanediol, 1,3-butanediol, 1,6
-Hexanediol, diethylene glycol, triethylene glycol, dipropylene glycol, etc. can be exemplified.

Typical strongly acidic cation exchange resins used as catalysts have sulfonic acid groups, such as styrene sulfonic acid cation exchange resins, phenolsulfonic acid cation exchange resins, and fluorinated alkyl sulfonic acid cation exchange resins. Ion exchange resins are a typical example, and various types are already commercially available. Typical commercially available ion exchange resins include Amberlyst 15, Amberlyte IR-118, DOWEX 5QWX12, Diaion 5K-IB, Diamondion pK-204, Duoly) C-20, Palmchit Q1 Nafion, etc. Illustrated.

The reaction of the present invention can be carried out by suspending such a cation exchange resin in the mixture of reaction raw materials described above, or by passing the mixture of reaction raw materials through a packed bed of cation exchange resin.
This can be easily done depending on the situation. The reaction ratio of the tertiary alkylating agent and the glycol is arbitrary, but in order to obtain the target product with high selectivity, it is preferable to carry out the reaction with an excess of glycol. , glycol in a proportion of 2 to 20 mol, particularly preferably 5 to 10 mol.

It is not necessary to use a diluent during the reaction, but a diluent can be used if desired.

The reaction temperature is 20 to 150°C, especially 60 to 9
A temperature range of 0°C is appropriate, and the reaction time (residence time in the flow method) may be about 0.25 to 2 hours.

In the reaction mixture from which the strongly acidic cation exchange resin was separated,
Since the eluted acid is included along with unreacted raw materials, the target product GMTE, and by-products such as glycol di-tertiary alkyl ether and isoolefin oligomer, the J' base is contact with a neutral ion exchange resin. The contact may be carried out directly to the reaction mixture from which the cation exchange resin has been separated, or may be carried out to the reaction mixture from which low-boiling substances such as isoolefins and dialkyl ethers have been distilled off, but the former embodiment is usually used. It is preferable to take the following method.

As the basic ion exchange resin, a strong basic quaternary ammonium salt type or a weakly basic amine type can be used. Among these, strongly basic ones are preferable from the viewpoint of acid removal effect, but medium basics or weakly basic ones are particularly preferable from the viewpoint of heat resistance, lifespan, ease of regeneration, etc. Examples of commercially available basic ion exchange resins that can be used in the present invention include Amberlis A-2
6, A-29, A-21, Amberlight IRA-93
8, IRA-47, IRA-94, Diaion WA-
10,71A-30, S-A N-1, DOWEX M SA-1, MWA-1, and the like.

These basic ion exchange resins may be used alone or mixed with a small amount of cation exchange resin. Some of the eluted acids may be in the form of salts such as sodium salts, but by using this combination, the salt form can be converted back to the acid form, making it easier to adsorb onto the basic ion exchange resin. do. Additionally, trace amounts of base may be eluted from the basic ion exchange resin, but this can be captured and extended catalyst life is expected.

It is not advantageous to carry out the treatment with a basic ion exchange resin at a very high temperature, and it is preferable to carry out the treatment at a temperature range of, for example, room temperature to 100°C. The treatment with the basic ion exchange resin can be carried out by suspending the resin in the reaction mixture or by passing the reaction mixture through a packed bed of resin, similar to the GMTE production reaction. A contact time of about 0.25 to 4 hours is sufficient.

By subjecting the reaction mixture from which the basic ion exchange resin has been separated to a conventional distillation operation, GMTE can be separated as an overhead fraction. At this time, a fraction containing a large amount of glycol is obtained as a bottom fraction, which can be used as is in the original reaction. Of course, if necessary, a small amount may be purged for purposes such as preventing accumulation of high-boiling substances.

FIG. 1 is a drawing showing one embodiment of the present invention.

A reactor 1 filled with a strongly acidic exchange resin is continuously fed with tertiary alkylating agent through line 7, fresh glycol through line 8 and recycled glycol fraction through line 12. The reaction mixture exiting the reactor 1 is sent from a pipe 9 to an acid removal tower 2 filled with a basic ion exchange resin, and then fed to a distillation tower B from a pipe 10 to remove low-boiling substances, such as unreacted raw materials. The tertiary alkylating agent, by-product alcohol, etc. are recovered from the top of the tower through pipe 16. The overhead fraction is further led to a separation column B, where the tertiary alkylating agent and by-product alcohol are separated and recovered from the top and bottom of the column through pipes 18 and 17, respectively. On the other hand, the bottom fraction of the distillation column 3 is led to the separation column 4 through a pipe 11, and monoether and by-product diether are extracted from the top of the tower through a pipe 13. Collect as bottom fraction. Meanwhile, diether is recovered from the top of the column through pipe 14. Separation tower 4
The unreacted glycol-rich fraction from the bottom of the column is transferred to reactor 1
be recycled and reused.

The industrially advantageous production of C) MTEE according to the present invention will now be described with reference to Examples.

Example 1 In Fig. 1, the reactor 1 is made of 5us-316 with a length of about 4 m and an inner diameter of 6 mm, and has a polystyrene type cation exchange resin catalyst Amberlite-2OOC (52 mesh units, manufactured by Olkali) 20 g (wet volume 57 m (J ) is filled.The acid remover B2 is 5US with a length of about 2.drn and an inner diameter of 6mm.
-316 and filled with strongly basic ion exchange resin 5AN-1 (manufactured by Mitsubishi Kasei) 57J (wet volume).

EG consisting of 90 parts of ethylene glycol (abbreviated as E()) recovered from the bottom of K distillation tg4 and 10 parts of new EG and methyl t-butyl ether (+, (abbreviated as 'I'BE)) were added to 1/10 mole of EG. The liquid was continuously fed to reactor 1 through a preheater so that the ratio was maintained at 70'C.
It was made to be H3V 4Hr. The liquid that has passed through the reactor 1 passes through a heat remover and is then transferred to an acid remover 2 whose temperature is controlled at 50°C.
to go into. There was a pressure regulating valve at the outlet of the deoxidizer, and the reaction liquid was continuously extracted through a cooler to control the liquid pressure to be 5 to 9/σ2G.The reaction liquid was extracted every 8 hours. The mixture was placed in a 3E three-dimensional flask and subjected to batch distillation using a 10-stage Oldershaw type distillation column. First, at normal pressure, isoethylene, MTBE,
Methanol was distilled off. Next G;> (3 (3mm)
The pressure was reduced to 1 g to obtain a 112-118°C fraction as the main fraction. At this time σ] bottom wetness (140 to 160
The bottom G was prepared with a new EG and reused, and some of it was blown.

No deterioration was observed in the activity of the catalyst in reactor 1 even during continuous operation for 272 hours using gas chromatography of the reaction solution partially drawn from line 9.

The material balance after distilling the reaction solution for 8 to 16 hours is as shown in Table 2, and the recovery rate of GMTE recovered as the main fraction is 9.
It was 8.8%. Loss due to decomposition during distillation is 0.9%
Met.

Table 2 The main fraction containing about 94% GMTE is a high purity product GMT
E was distilled under reduced pressure at 10-100 mmHg, but GMTg did not decompose during the distillation.

Example 2 Weakly basic ion exchange resin WA was placed in the deoxidizer 2 in Example 1.
-10 (manufactured by Mitsubishi Kasei) 57+r+e (wet volume) was filled, and the same procedure as in Example 1 was performed except that the temperature was controlled at 70°C.

M T B E conversion rate after 208 hours was 77.6 mol%
, GMTE selectivity was 95.5 mol%, and no deterioration was observed in the catalyst activity of reactor 1.

The recovery rate of GMTE recovered as the main fraction when the reaction solution was distilled for 8 to 16 hours was 98.5%. The loss due to decomposition during distillation was 1.3%.

Example 5 Weakly basic ion exchange resin WA was placed in the deoxidizer 2 in Example 1.
-1 (manufactured by Mitsubishi Kasei) 57J (wet volume) was filled, 70
The process was carried out in the same manner as in Example 1 except that the control was carried out at "c".

Even after 208 hours, no deterioration was observed in the catalyst activity of reactor 1.

The reaction solution after 8 to 16 hours was recovered as the main fraction when distilled, and the recovery rate of TCGMTE was 98.2%. The loss due to decomposition during distillation was 1.6%.

Example 4 Strongly basic ion exchange resin Amberlis)-26 (manufactured by Organo) 57 mn (wet volume) was placed in the deoxidizer 2 in Example 1.
The procedure was the same as in Example 1 except that EG was filled with EG and EG was not reused.

The recovery rate of GMTE recovered as the main fraction when the reaction solution was distilled for 8 to 16 hours was 98.7%.

The decomposition rate of GMTE during distillation was 1.1%.

Example 5 Strongly basic ion exchange resin 5A was placed in the deoxidizer 2 in Example 1.
The same procedure as in Example 1 was conducted except that 40 mg (wet volume) of N-1 (manufactured by Mitsubishi Kasei) and 20 m5 (wet volume) of strongly acidic ion exchange resin 5AN-1 (manufactured by Mitsubishi Kasei) were mixed and filled.

Even after 272 hours of continuous operation, there was no sign of any deterioration in the activity of the catalyst in reactor 1, and the conversion rate of MTBE was 77.2 mol% and the selectivity of GMTE was 95.3 mol%.

The recovery rate of ()MTE recovered as the main fraction when the reaction solution was distilled for 8 to 16 hours was 98.7%.

The decomposition rate of C)MTE during distillation was 1.2%.

Comparative Example 1 The same procedure as Example 1 was carried out except that the deoxidizer 2 was not filled with anything and no deoxidizing treatment was performed.Even after 208 hours of continuous operation, the activity of the catalyst in the reactor 1 did not deteriorate at all. was not recognized.

However, the material balance obtained by distilling the reaction solution for 8 to 16 hours was as shown in Table 3. QM recovered as main fraction
The recovery rate of TE was 73.7%, and the decomposition rate during distillation was 26.8%.

Table 3 Comparative Example 2 Reactor 1 was filled with 20 g of Amberley)-200c catalyst and heated to 70°C. The molar ratio of MTBE/EG is 1
The liquid was sent to the reactor 1 using each pump so that the amount of water was 10%. At this time, the reaction was carried out at LH8V 4Hr', and a large amount of reaction liquid was produced without passing through the deoxidizer 2. The acid concentration in the reaction solution was 4 ppm in terms of sulfuric acid.

Add an amount of NaHCO5 equivalent to the amount of acid in this reaction solution,
When the same distillation as in Example 1 was carried out, the ()MTE recovered as the main fraction was substantially GM with a recovery rate of 99.2%.
TE did not decompose.

However, when 90 parts of the residual liquid after this distillation and 10 parts of fresh EG were prepared and reused in the reaction, the activity of the catalyst showed a tendency to continuously decrease, and the conversion rate of MTBE was 77.7% at the beginning of operation. 5 mol%, after 208 hours, M
The conversion rate of T n E decreased to 73.5 mol %.

Comparative Example 3 When the EG recovered by further simple distillation of the pot residue obtained in Comparative Example 2 was reused in the reaction, the catalyst activity was 208
There was no decrease at all after a while, and the conversion rate of MTBE was 77.6 mol%, the same as at the beginning of the reaction.

Comparative Example 4 The same procedure as in Example 1 was carried out except that the deoxidizer 2 was filled with 60 J (wet volume) of hydrotalcyanide.

The recovery rate of ()MTE recovered as the main fraction when distilling the reaction solution for 8 to 16 hours was 98.9%, and GM
The decomposition rate of TE was 8% on the skin.

However, the activity of the catalyst decreased continuously, and the conversion of MTBE after 208 hours was 64.1 mol%.

[Brief explanation of the drawing]

FIG. 1 is a drawing showing one embodiment of the present invention.

Claims (1)

[Claims] (1) (A) A tertiary alkylating agent from the group consisting of dialkyl ethers and isoolefins containing one tertiary alkyl group is reacted with glyfur in the presence of a strongly acidic ion exchange resin. a step of producing a glycol mono-tertiary alkyl ether; CB) a step of contacting the reaction mixture with a basic ion exchange resin prior to distillation separation of the glycol mono-tertiary alkyl ether; (C) a step of contacting the contact-treated reaction mixture; (D) a step of recycling the glycol recovered as the bottom fraction of the step (C) to the step (A). A method for producing class alkyl ether.