JPS6034939B2 - Method for suppressing decomposition of ethylene glycol monotertiary alkyl ether - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for suppressing the decomposition of ethylene glycol monotertiary alkyl ether (hereinafter sometimes abbreviated as MAE).

Monoalkyl ethers of ethylene glycol are generally very useful compounds as solvents, such as n-
Butyl cellosolve (ethylene glycol mono-normal butyl ether), methyl cellosolve, ethyl cellosolve, etc. are produced and used on a large scale industrially today.

In addition, ethylene glycol monotertiary alkyl ethers, especially ethylene glycol monotertiary butyl ether, are used as solvents, dispersants, diluents, etc. in industrial fields such as paints and inks. It is a useful substance with excellent properties when used. M
A common method for producing AE is a method in which a tertiary olefin or a tertiary olefin-containing hydrocarbon is reacted with ethylene glycol in the presence of an acid catalyst.

In that case, the effectiveness of the method of using a strongly acidic cation exchange resin as an acid catalyst is disclosed in U.S. Pat.
182004, 1972-2941, etc. are well known. Crude MAE produced by these known methods
Among them are usually unreacted tertiary olefins, hydrocarbons containing or not containing tertiary olefins, ethylene glycol,
Creation of olefins Because it contains orikoma, ethylene glycol ditertiary alkyl ether, water, and the reaction solvent used as necessary, purification treatments such as extraction, distillation, and extractive distillation are required to obtain high-purity MAE. Requires. When producing high purity MAE from such crude MAE, crude M
If even a small amount of acidic substances are present in AE, there is a problem that MAE decomposes into tertiary olefin and ethylene glycol during purification processes that involve heating, such as distillation, and the yield of high-purity MAE decreases significantly. I understand.

Such decomposition of MAE by an acid occurs even when an acid such as sulfuric acid or an organic sulfonic acid is present at a rate of about 6.2 x 10-6 mol/acid, and is an extremely sensitive reaction. In addition, such decomposition reactions are accelerated by heating, and are significantly accelerated at temperatures of about 100 OO or higher. For example, in a mixture consisting of 9% by weight of MA8 and 1% by weight of ethylene glycol, 6% by weight of sulfuric acid is present.
This mixture contains 1
When heated to 40-150oo, more than 90% of MAE decomposes in 60 minutes. Moreover, such a decomposition reaction takes about 1
It also progresses gradually when stored in a tank at a temperature below 0 o pm, for example at room temperature. On the other hand, although it has been shown that MAE is generally synthesized from tertiary olefin and ethylene glycol using an acid catalyst, small amounts of acidic substances are often mixed into the crude MAE obtained by such a method.

For example, when MAE is produced by a fixed bed pressurized liquid phase flow reaction method using a strongly acidic intestinal ion exchange resin (for example, Amberlyst 15 manufactured by Rohm & Haas) as an acid catalyst, strongly acidic cations are present in the crude product. Contains a small amount of acidic substances such as organic sulfonic acids melted from the exchange resin. Although the amount of eluted acid in such a crude product varies depending on the reaction temperature and contact time, acid leaching is continuously observed even when the reaction is continuously carried out for one year. That is, for example, the amount of acidic substances dissolved from Amberlyst 15 during the above reaction is particularly large at the beginning of the continuous reaction, and the concentration in the crude product may exceed 0.01 chemical equivalent/s. The eluted acid concentration then rapidly decreases to 10-4 to 105 chemical equivalents/so after several days from the start of the reaction, and continues to gradually decrease after that, but even after a considerable period of time elapses, the eluted acid concentration still remains. continue. The fact that acidic substances are eluted from such a strongly acidic cation exchange resin catalyst during the reaction also applies when a strongly acidic cation exchange catalyst is used in the reaction of isoptylene and methanol, the alkylation reaction of phenol, etc. In the process of refining crude products, such acids mainly cause corrosion in various parts of the equipment, so aqueous solutions of strong basic substances such as caustic soda, calcium oxide, calcium hydroxide, etc. A method of neutralizing by adding is known.

However, with this method, it is not only difficult to separate the salts produced in the neutralization reaction, but also difficult to control the amount of alkali added in response to fluctuations in the concentration of eluted acid, and if excessively added, strong alkaline substances Purification must be carried out under conditions in which the Furthermore, in JP-A No. 53-65809, hydrotalcite (mother M.
g0, Yama203, NH20), and a method of treatment with a solid basic substance such as magnesium oxide is described. However, this method has drawbacks such as the need to install a new packed column and the need for post-treatment of a large amount of solid base after use. The inventors of the present invention have conducted intensive research to solve the problems under such circumstances, and have found that by bringing the rough K ship E into contact with at least one of metal iron, iron oxide, and iron hydroxide, The present invention was completed based on the discovery that the decomposition of MAE caused by a small amount of acidic substances mixed in crude MAE can be significantly suppressed.

That is, the gist of the present invention is that crude MA containing acidic substances
The present invention provides a method for suppressing the decomposition of MAE, which comprises bringing crude MAE into contact with at least one of metal iron, iron oxide, and iron hydroxide. In the present invention, MAE' is represented by the general formula ROC2day40day, where R has 4 or more carbon atoms,
For example, it represents 4 to 6 tertiary alkyl groups.

Specifically, the tertiary alkyl group is tertiary butyl, tertiary amyl, 1,1,2-trimethylpropyl, 1-methyl-1-ethylpropyl, 1
, 1-dimethylbutyl and the like. Also, crude MAE
There may be other components other than MAE and acidic substances, for example, using commercially available strong acidic cation exchange≠sword resin Amberlyst 15 as a catalyst,
The molar ratio of ethylene glycol and tertiary olefin is approximately 0.
．． A mixture consisting of a naphtha cracked hydrocarbon fraction containing a tertiary olefin in a ratio of 2 to 20 parts and ethylene glycol is heated at a reaction temperature of about 40 to 120°C and a pressure of about 3 to 40 k.
9/Su, liquid space velocity of all raw materials approximately 0.1 to 3.0 hr-1
Examples include components contained in crude MAE obtained by reacting in a fixed bed pressurized liquid phase flow reaction system.

That is, the components contained in the crude MAE include reacted tertiary olefins, hydrocarbons containing or not containing tertiary olefins, ethylene glycol, synthetic olefin oligomers, ethylene glycol ditertiary alkyl ethers, etc. It will be done. Also, add water and a third
When using nasal water or a reaction solvent in which the molar ratio of olefins is 0.8 or less, the corresponding tertiary alcohol and its reaction solvent are included. The amount of these components contained in crude MAE is usually about 0.5 to 90% by weight.
It is. Further, the metal iron referred to in the present invention may be simply composed of iron element, or may be an alloy containing iron such as carbon steel.

Further, the form thereof may be powder, granule, plate, or any other form. Other preferred forms include cases where metal iron or carbon steel is used for extraction columns, distillation columns, evaporators, piping, heaters, tanks, etc. used in the MAE purification process. be. Further, in the present invention, iron oxides include ferrous oxide, diferric oxide, mixtures thereof, iron rust, etc., and iron hydroxides include ferrous hydroxide, ferric hydroxide, and mixtures thereof. and iron hydroxide obtained by reacting a water-soluble iron salt such as iron sulfate or iron chloride with an alkali.

In the present invention, the amount of metallic iron, iron oxide, iron hydroxide, etc. to be added in order to suppress the decomposition of MAE is at least an equimolar amount with respect to the amount of acidic substance mixed into crude MAE. is necessary, but there is no problem even if it is added in large excess.

The amount of iron added is usually approximately 1 per crude MAEI.
0-6 chemical equivalents or more, preferably about 10-5 chemical equivalents or more. In addition, as an example of an acidic substance in the present invention, although the chemical structure is not clear, it is eluted from a strongly acidic ion exchange resin used as a catalyst during the synthesis of MAE,
A strong acidic substance that is mixed into the reaction product, or a small amount of a strong acidic substance that is originally contained in the reaction raw material.

Other examples of strong acidic substances include sulfuric acid and sulfonic acids. The present invention can be implemented, for example, in the following forms.

In other words, when purifying crude MAE containing acidic substances by evaporation, distillation, extractive distillation, etc., before distillation or evaporation, etc. One or more of metallic iron, iron oxide, and iron hydroxide may be added to the distillation or evaporation vessel in an amount of The rough MAE may be made to come into contact with metal iron or the like. The effect of suppressing the decomposition of MAE by iron content is manifested by the contact between crude MAE and iron content, and the contact time is usually at least 1 second, preferably at least 1 minute. Also, M.A.
Metallic iron,
At least one of iron oxide and iron hydroxide is added, and the temperature is about 80 to 350°C, preferably about 100 to 160°C.
heat treatment at o for several minutes to several tens of hours to prepare a solution in which iron and iron compounds are dissolved in about 10 to several tens of pm,
Even when this solution is mixed with crude MAE containing an acidic substance and distilled, a remarkable effect of suppressing the decomposition of MAE can be obtained.

Note that iron, iron oxide, iron hydroxide, etc. may be dissolved in MAE or crude MAE at a low temperature of about 80 qo or less, but in this case, the time required for dissolution is several hours or more, preferably about 1 feeding hour. This requires a longer period of time. The ratio of mixing the solution containing iron and iron compounds to the crude MAE containing acidic substances should be such that the amount of dissolved iron and iron compounds is at least equimolar to the amount of acidic substances. . In addition, when mixing this solution of iron and iron compounds with crude MAE containing an acidic substance, by adding iron, iron oxide, iron hydroxide, etc. to the crude MAE in advance, MAE can be added during distillation. The effect of continuously suppressing the decomposition of is obtained. The present invention is particularly suitable for processing crude MAE that involves heating operations such as evaporation, distillation, extractive distillation, etc. at a temperature of about 50 qo or more, preferably about 80 to 350°C, but it is suitable for processing crude MAE that involves heating operations such as extraction, storage, transportation, etc. This also applies to

According to the present invention, the decomposition of MAE can be significantly suppressed by adding at least one of metallic iron, iron oxide, and iron hydroxide to crude MAE in which a small amount of acidic substances coexist, but the mechanism of action is It's not clear.

However, by carrying out the method of the present invention, the decomposition of MAE can be suppressed extremely effectively and with simple operations when purifying MAE, making it possible to produce highly pure MAE with high yield. Ta. The method of the present invention will be specifically explained below by giving Reference Examples, Examples, and Comparative Examples.

Example 1 Pure ethylene glycol monotertiary butyl ether (hereinafter referred to as
(abbreviated as MBE), 0.3 parts by weight of para-toluenesulfonic acid and 0.6 parts by weight of reduced iron powder were added and heated at 15,000 for 3 hours.
Although some decomposition of E occurred in the initial stage of heating, the decomposition was suppressed thereafter. The results are shown in Table 1. Table I Example 2 Using the same apparatus as in Example 1, 0.6 parts by weight of reduced iron was added to parts by weight of pure MBEIOO, and the mixture was heated at 154°C for 50 minutes.
After heating for an hour, it was cooled to room temperature.

Thereafter, 0.3 parts by weight of para-toluenesulfonic acid was added and the mixture was heated at 15,000 for 3 hours. As a result, the decomposition of MBE was significantly suppressed from the initial stage of heating. The results are shown in Table 2. Table 2 1 Example 3 An experiment was carried out in the same manner as in Example 2 except that sulfuric acid was used instead of para-toluenesulfonic acid. As a result, the decomposition rate of MBE was 2.4%. .

Example 4 Using the same apparatus as in Example 1, 0.6 parts by weight of iron hydroxide prepared using ferrous sulfate and sodium hydroxide was added to parts by weight of pure MBEIOO, and this was mixed at 150 qo. 5
After heating for an hour, the mixture was cooled to room temperature, and then 0.3 parts by weight of para-toluenesulfonic acid was added and heated at 120q0 for 2 hours.

The scale rate of MBE at this time was 13%. Moreover, as a result of subsequent heating at 151° C. for 2 hours, the decomposition rate of MBE was 25%. Example 5 In Example 2, iron rust collected from the surface of one outdoor steel frame was used instead of reduced iron powder, and the heating time at 15000C was 2 hours after adding para-toluene sulfonic acid. As a result of conducting an experiment in the same manner as in Example 2,
The decomposition rate of MBE was 17%.

Example 6 An experiment was conducted in the same manner as in Example 5, except that a metal iron plate with a thickness of 0.1 and a surface area of 7.6 was used instead of iron rust. As a result, the decomposition rate of MBE was was 3%.

Example 7 A solution of 3 parts by weight of para-toluene sulfonic acid in 3 parts by weight of MBEIOOO was poured into a glass Oldershaw distillation apparatus manufactured by Himeso.
~1 willow of spherical reduced iron was added and distillation was carried out at normal pressure.

At this time, the temperature at the top of the distillation column was 15°C, and the time required for distillation was 3 hours. As a result of this distillation, the decomposition rate of MBE was 3%. Example 8 Commercially available macroporous strongly acidic cation exchange resin Amberlyst 1 was placed in a stainless steel reaction tube with an inner diameter of 1.34 mm.
5, and a naphtha-decomposed C4 fraction (containing 45% by weight of isobutylene) and ethylene glycol were supplied from the upper part of the reaction tube at a reaction temperature of 45°C and a pressure of 20k9/kg.

The relative amounts of ethylene glycol and C4 fraction were determined so that the molar ratio of ethylene glycol and isobutylene was 2.7. The composition is 27.0 mol% MBE, 70.1 mol% ethylene glycol, 2.0 mol% ethylene glycol ditertiary butyl ether, 0.9 mol% diisobutylene, and trace amounts of triisobutylene and ethylene glycol monosecondary butyl ether. , and 10-5 equivalents/unit of lacquer acid. This crude MBE is passed through an iron distillation column with two theoretical plates in an amount necessary to completely remove ethylene glycol di-butyl ether and diisobutylene from the top of the distillation column as an azeotrope. As a result of continuous atmospheric extractive distillation while adding water, diisobutylene, ethylene glycol ditertiary butyl ether and MBE were extracted from the top of the column.
A co-brood mixture of water and water was obtained, and a mixture of ethylene glycol and MBE was obtained from the bottom of the column. At that time, the temperatures at the top and bottom of the column were approximately 99 oo and 17 0, respectively, and the average residence time of MBE in the distillation column was approximately 2 hours. In this distillation, analysis of the effluents from the top and bottom of the column revealed that the decomposition rate of M-old-E during the distillation operation was 1% or less. Example 9 An experiment was conducted in the same manner as in Example 5, except that reduced iron powder was used instead of iron rust and pure ethylene glycol monotertiary amyl ether was used instead of pure MBE. As a result, the decomposition rate of ethylene glycol monotertiary amyl ether was 3%.

Example 10 The experiment was carried out using the same machine as in Example 9, except that pure ethylene glycol mono-1,1,2-trimethylpropyl ether was used instead of pure ethylene glycol mono-tertiary amyl ether. As a result, the decomposition rate of ethylene glycol mono 1,1,2-trimethylpropyl ether was 3.8%.

Example 11 A stainless steel reaction tube with an inner diameter of 1.34 mm was filled with strongly acidic cation exchange resin Amberlyst 15, and the reaction temperature was 600 ml.
0.0 and a pressure of 20×9/kg, a naphtha cracked C4 fraction (containing 1% by weight of isobutylene) and ethylene glycol were fed from the upper part of the reaction tube.

The molar ratio of ethylene glycol and isoptylene at this time was determined to be 1.011. The composition of the crude MBE excluding the C4 hydrocarbon fraction obtained in this way is
62.2 mol%, ethylene glycol 30.1 mol%,
Ethylene glycol ditertiary butyl ether7.
3 mol% diisobutylene, 0.4 mol% diisobutylene and a certain amount of triisobutylene, ethylene glycol monosecondary butyl ether, and eluting acid 1.2 x 10-5 equivalents/
It includes that. In addition, 90 parts by weight of ethylene glycol, parts by weight of MBEI, and 3 parts by weight of reduced iron powder were placed in a glass container equipped with a reflux condenser, and this was heated at 160 qo for 1 feeding time to obtain dissolved and suspended iron and iron. 10 parts by weight of a mixture containing 51 pm of the compound was mixed with 90 parts by weight of the above crude MBE, and this was mixed in the same manner as described in Example 8 using an iron distillation column having 2 theoretical plates. Continuous atmospheric pressure extractive distillation was carried out using the following method. The average residence time of MBE at this time was about 2 hours, and the temperatures at the top and bottom of the tower were about 9900 and 176 pm, respectively.
Met. In this distillation, as a result of analyzing the column content and the effluent from the column bottom, the decomposition rate of M old E during the distillation operation was 0.
．． It was less than 1%. Example 12 Using the same reaction tube and catalyst as in Example 11, reaction temperature 60 oo, pressure 20
In k9/2, naphtha cracked C4 fraction (containing 18% by weight of isobutylene), ethylene glycol' and water were fed from the upper part of the reaction tube.

The relative amounts of ethylene glycol, C4 fraction, and water were determined so that the molar ratio of ethylene glycol:water:isobutylene at this time was 1:0.43:1.45. The composition of the crude MBE excluding the C4 fraction obtained in this way is M
Old E 21.2 mol%, ethylene glycol 35.0 mol%, ethylene glycol ditertiary butyl ether 13.1 mol%, Yuichi Shiary Butyl Alcohol 8.5
mol %, diisoptylene 0.1 mol %, water 21.6 mol %, and eluting acid 3.2 x 10-5 equivalents/h. To 90 parts by weight of this crude MBE, ethylene glycol containing 51 pm of iron obtained in Example 11 and M old E
10 parts by weight of the mixture were mixed and subjected to continuous atmospheric extractive distillation in the same manner as in Example 11. The average residence time of M old E at this time was about 2 hours, and the temperatures at the top and bottom of the column were about 99 oo and 17 o, respectively. As a result of analyzing the effluent from the top and bottom of the column in this distillation,
The decomposition rate of MBE during the distillation operation was 0.1% or less.
Reference Example When parts by weight of pure MBEIO were placed in a glass container equipped with a reflux condenser and heated at 14yo for 3 hours, no decomposition of MoldE occurred.

Comparative Example Using the same apparatus as in the reference example, a mixture of pure MBEIOO and 0.3 parts by weight of para-toluenesulfonic acid was heated at 145 qo for 2 hours, resulting in an MBE of 93.4.
% decomposed.

Claims (1)

[Claims] 1. In order to suppress the decomposition of the ethylene glycol monotertiary alkyl ether containing an acidic substance, the crude ethylene glycol monotertiary alkyl ether is brought into contact with at least one of metallic iron, iron oxide, and iron hydroxide. A method for suppressing the decomposition of ethylene glycol monotertiary alkyl ether.