JP2002308813A - High purity diisopropyl ether and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide high purity diisopropyl ether suitably used as a synthesizing extraction solvent for medicines, food or the like and to produce the same from low purity diisopropyl ether in an economically advantageous manner without generating an environmental problem. SOLUTION: The purpose can be achieved by high purity diisopropyl ether containing a very small amount of hexanes. High purity diisopropyl ether is manufactured by subjecting diisopropyl ether containing unsaturated hydrocarbon to hydrogenation treatment before distilling and refining the same.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-purity diisopropyl ether and a method for producing the same, and more particularly to a high-purity diisopropyl ether and a high-purity diisopropyl ether used as a solvent for synthesis and extraction of pharmaceuticals and foods. The present invention relates to a method for producing from diisopropyl ether by distillation purification.

[0002]

2. Description of the Related Art As a solvent for synthesizing and extracting pharmaceuticals and foods, diisopropyl ether is 99% or 99.5%.
High purity of at least 100% is required. Diisopropyl ether is industrially produced by a catalytic reaction of isopropyl alcohol and propylene, or is recovered as a by-product oil in the production of isopropyl alcohol.

[0003] The crude diisopropyl ether obtained here contains hexenes by-produced in the production process (in the present invention, it refers to aliphatic unsaturated hydrocarbon compounds having 6 carbon atoms). (73 ° C.) is close to the boiling point of the desired diisopropyl ether (69 ° C.), so that it is often difficult to produce high-purity diisopropyl ether having a purity of 99% or more with a normal distillation method and distillation apparatus.

A conventionally known method for solving this problem is disclosed in Japanese Patent Laid-Open Publication No.
JP-A-63239) discloses a method in which a solvent (isopropyl alcohol or acetonitrile) is added to separate and distill hexenes as an azeotropic composition.

[0005]

A known method (Japanese Patent Laid-Open No.
No. 63239) is an effective means for purifying crude diisopropyl ether having a small content of hexenes to produce high-purity diisopropyl ether, but having a large content of hexenes, for example, 20% by mass. As described above, when applied to crude diisopropyl ether, there is a problem that the amount of solvent to be added and the amount of diisopropyl ether entrained as an azeotropic composition increase. This is not only economically disadvantageous but also environmentally unfavorable due to increased waste.

A first object of the present invention is to provide a high-purity diisopropyl ether which is suitably used as a solvent for synthesizing and extracting pharmaceuticals and foods, and a second object of the present invention is to provide such a high-purity diisopropyl ether. An object of the present invention is to provide a method for producing pure diisopropyl ether from low-purity diisopropyl ether by distillation and purification economically and without environmental problems.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted various studies in order to solve the above-mentioned problems. As a result, the crude diisopropyl ether containing hexenes is hydrogenated, and the corresponding hexanes (in the present invention, carbon To the boiling point of all hexenes (69 ° C.) or lower, and distilling the crude diisopropyl ether after hydrogenation. In particular, the present inventors have found that crude diisopropyl ether can be efficiently purified to produce high-purity diisopropyl ether, particularly by extractive distillation or azeotropic distillation, thereby completing the present invention.

The first aspect of the present invention is a high-purity diisopropyl ether containing a small amount of hexanes.

A second aspect of the present invention is a process for producing high-purity diisopropyl ether, which comprises distilling diisopropyl ether containing hexenes after hydrogenation.

A third aspect of the present invention is the method according to the second aspect, wherein the distillation is azeotropic distillation.

A fourth aspect of the present invention is the method according to the second aspect, wherein the distillation is extractive distillation.

According to a fifth aspect of the present invention, in the method according to the third aspect, the azeotropic composition component to be added is isopropyl alcohol.

In the present invention, the boiling point of all hexenes is equal to or lower than the boiling point of diisopropyl ether (69 ° C.) by hydrogenating the crude diisopropyl ether containing hexenes and converting them to the corresponding hexanes. And by distilling the crude diisopropyl ether after the hydrogenation treatment, in particular, extractive distillation or azeotropic distillation to efficiently purify the crude diisopropyl ether to contain high-purity diisopropyl ether containing a small amount of hexanes. Can be produced economically and without environmental concerns.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the method of the present invention will be described in more detail. The raw material diisopropyl ether used in the present invention may be one produced as intended, or one obtained as a by-product when producing another compound (for example, isopropyl alcohol), or diisopropyl used as a synthesis solvent or an extraction solvent. The recovered ether may be used.

The purity of the crude diisopropyl ether used as raw material is not particularly limited.
This is effective when crude diisopropyl ether of from 50 to 50% by mass, preferably from 2 to 30% by mass is used as a raw material. 1
When the amount is less than 50% by mass, the yield is improved by the present invention, but the effect is small. When the amount exceeds 50% by mass, it is difficult to obtain a high yield by the method of the present invention.

The crude diisopropyl ether in the present invention may further contain impurities other than hexenes such as water, alcohol and heavy hydrocarbons.

The hydrogenation in the present invention is carried out by contacting crude diisopropyl ether with hydrogen in the presence of a catalyst. The reactor may be a batch type or a continuous type.
The catalyst to be used may be any catalyst as long as hexenes can be hydrogenated.
A catalyst supporting a metal element belonging to Group I (and its oxides and sulfides) is industrially advantageous. For example, palladium carbon, rhodium carbon, platinum alumina, nickel silica and the like can be mentioned.

The hydrogenation conditions are not particularly limited as long as the reaction proceeds smoothly.
20 MPa, temperature 0 ° C. to 200 ° C., catalyst amount 1 to 10% by mass, LHSV can be selected from the range of 0.1 to 30 h ⁻¹ . Preferably, the hydrogen pressure is 0.01 MPa to 5 MPa and the temperature is 20 ° C. to 80 ° C.

The distillation method in the present invention can be appropriately selected from ordinary distillation (simple distillation), extractive distillation and azeotropic distillation, depending on the type, amount and composition of the hexanes contained.

The simple distillation can be used when the boiling point of hexanes is sufficiently lower than the boiling point of diisopropyl ether or when the amount of hexanes is relatively small.

In the extractive distillation, a polar solvent such as dimethyl sulfoxide, sulfolane, 1-methylpyrrolidinone or the like is added to form an interaction with these polar solvents, thereby increasing the boiling point difference between hexanes and diisopropyl ether to purify the extract. Is facilitated.

For example, when the hydrogenated crude diisopropyl ether is subjected to extractive distillation, the relative specific volatility between diisopropyl ether and normal hexane (boiling point: 69 ° C.) having the closest boiling point in simple distillation is equivalent to a boiling point difference of 18 ° C. However, in the case of simple distillation, the relative specific volatility of hexenes whose boiling point is closest to that of diisopropyl ether, for example, 2-methyl-2-pentene (67.3 ° C.) can be determined by a simple distillation without a hydrogenation treatment. It can only be expanded considerably. In addition, when hydrogenation is not performed, hexenes having a higher boiling point than diisopropyl ether coexist, and the relative specific volatility of these and diisopropyl ether becomes smaller than in the case of simple distillation. Does not.

In azeotropic distillation, purification is carried out by adding a solvent which forms an azeotropic composition with hexanes and distilling these azeotropic compositions at a boiling point lower than the boiling point of either hexanes or diisopropyl ether. It is characterized by facilitation.

As the solvent, a solvent which is azeotropic with hexane and whose azeotropic temperature is lower than the boiling point of diisopropyl ether is selected. Specifically, methanol, ethanol,
Isopropyl alcohol, acetone, methyl ethyl ketone and the like. For example, when simple distillation is performed, azeotropic distillation distillation is performed by adding methanol to hydrogenated crude diisopropyl ether and non-hydrogenated crude diisopropyl ether having a substantial distillation start temperature of about 60 ° C.
In the former case, the distillation start temperature can be reduced by about 12 ° C., but in the latter case it is about 7 ° C.

In using the azeotropic distillation, the hydrogenation of the raw material is not essential in principle, but the amount of the additional solvent necessary for removing hexanes and the component of the azeotropic composition are lost by the hydrogenation. The amount of diisopropyl ether can be reduced. In the above example of the methanol addition system, the required amount of added methanol is 20
%, And the loss of nearly 40% of diisopropyl ether as an azeotropic composition without hydrogenation can be reduced to about 16%.

The hydrogenation apparatus and distillation apparatus used in the present invention may be either a batch type or a continuous type. Further, the hydrogenation apparatus and the distillation apparatus may be used alone or continuously. The distillation apparatus may be provided with one distillation column, but when the crude diisopropyl ether as a raw material contains impurities having a high boiling point, the distillation apparatus has a two-column configuration, and the first column distillate or bottoms is used in the second column. Can be further purified.

In the production method of the present invention, high-purity isopropyl ether can be obtained by purifying the crude isopropyl ether to an arbitrary purity corresponding to the purity of the crude isopropyl ether. In particular, high purity of 99% by mass or more, and more preferably 99.5% by mass or more, can be achieved, and hexanes, which is one of the impurities, can be reduced to 1% by mass or less, further preferably 0.5% by mass or less. It is possible.

[0028]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples. However, the present invention is not limited to the Examples without departing from the gist of the present invention. Example 1 1,500 g of crude diisopropyl ether (purity: about 77% by mass) containing about 20% by weight of hexenes
In an autoclave, hydrogen pressure 0.3 MPa, temperature 40
The mixture was hydrogenated at 20 ° C. for 30 minutes using 20 g of 5% palladium on carbon as a catalyst. After the reaction, the catalyst was separated, and hydrogenated crude diisopropyl ether 1,44 substantially free of hexenes was added.
0 g was obtained. Next, 150 g of the hydrogenated crude diisopropyl ether and methanol were placed in a 300 ml three-necked flask equipped with a 20 cm long distillation column and a condenser.
g of the added raw material was distilled at a charged reflux ratio of 20. The distillate was analyzed, and after confirming that all the added methanol was distilled, the distillation was stopped. From the bottom of the column, 68 g of purified diisopropyl ether having a purity of 99.5% was obtained. The content of hexanes in this purified diisopropyl ether was 0.2
% By mass.

Example 2 15 g of isopropyl alcohol was added to 150 g of the same hydrogenated crude diisopropyl ether used in Example 1, and distillation was carried out in the same manner. As a result, 59.1% pure diisopropyl ether was purified.
6 g were obtained. The hexane content in this diisopropyl ether was 0.6% by mass.

Comparative Example 1 The crude diisopropyl ether was distilled under the same conditions as in Example 1 except that the crude diisopropyl ether (purity: about 77% by mass) was used without hydrogenation. . As a result, 44 g of purified diisopropyl ether having a purity of 93.7% was obtained. The hexane content in this diisopropyl ether was 5.7% by mass.

[0031]

The high-purity diisopropyl ether containing a small amount of hexane according to the present invention has a remarkable effect that it can be suitably used as a solvent for synthesizing and extracting pharmaceuticals and foods.

The process for producing high-purity diisopropyl ether of the present invention, characterized in that diisopropyl ether containing hexenes is subjected to hydrogenation treatment and then distillation, is economically advantageous from low-purity diisopropyl ether and without environmental problems. This has a remarkable effect that high-purity diisopropyl ether can be produced.

Claims (5)

[Claims] 1. A high-purity diisopropyl ether containing a small amount of hexanes. 2. A method for producing high-purity diisopropyl ether, comprising distilling diisopropyl ether containing hexene after hydrogenation. 3. The method according to claim 2, wherein the distillation is azeotropic distillation. 4. The method according to claim 2, wherein the distillation is extractive distillation. 5. The method according to claim 3, wherein the azeotropic composition component to be added is isopropyl alcohol.