JPS5854134B2 - Ketone purification method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for purifying a ketone produced by decomposition of an aralkylhydroperoxytraic acid, and more specifically, a method for purifying a ketone produced by the decomposition of an aralkylhydroperoxytraic acid, and more specifically, a method for purifying a ketone produced by the general formula Ar 0H or a hydrogen hydride residue, and R1 to R4 represent a lower alkyl group.

This invention relates to a method for purifying a ketone by selectively aldol condensing a trace amount of aldehyde in a crude ketone obtained by topping distillation of a product obtained by acid decomposition of an aralkyl hydroperoxide shown in ).

The method of oxidizing an aromatic hydrocarbon in which an alkyl group is substituted to obtain an aralkyl hydroperoxide, and then decomposing it with an acid to produce a ketone and a phenol is well known as the cumene method.

In addition, when aralkyl hydroperoxide such as cumene hydroperoxide is subjected to acid decomposition in the cumene process, the product contains acetone and phenol as well as trace amounts of impurities such as acetaldehyde, propionaldehyde, n.
It is also well known that -butyraldehyde, isobutyraldehyde, etc. are contained.

Even if the crude acetone obtained by topping distillation of such acid decomposition products is directly rectified, aldehydes will be mixed into the purified acetone, reducing the purity and quality of the acetone. In addition, a method has been adopted in which aldehydes are converted into high-boiling substances through aldol condensation, and then acetone is distilled and recovered, and the high-boiling substances are discharged from the bottom of the acetone purification column.

However, this method requires an increase in utility due to the addition of an aqueous alkaline solution, and when the distillation temperature is raised to increase the recovery rate of acetone, high-boiling substances decondense in the acetone purification column and return to aldehydes. , since aldehyde is mixed into purified acetone, the residual acetone concentration should be reduced to 2 to 1.
It was necessary to keep it at 0%.

As a result, there were drawbacks such as a low recovery rate of purified acetone, a high acetone content in the waste water, and a high COD (chemical oxygen demand) of the waste water.

The present inventor has discovered that the drawback of the conventional ketone purification method that utilizes aldol condensation of aldehydes is that the alkali used as a catalyst for the aldol condensation of aldehydes flows into the ketone purification column and decondenses the aldol condensation product at the bottom of the column. They investigated what happens due to this and came up with the idea that if a solid base is used as the alkali, it is possible to prevent the catalyst from flowing into the acetone purification tower.

As a result of examining various solid bases, we found that when inorganic chemicals such as calcium oxide, magnesium oxide, sodium carbonate, potassium carbonate, calcium hydroxide, and sodium silicate are used, the rate of condensation of aldehydes is slow. The disadvantage is that these solid bases dissolve in the water present in a small amount in the ketone and are lost, resulting in a short catalyst life and a low ketone recovery rate. I learned that it was not suitable for me.

Furthermore, when an anion exchange resin having a tertiary ammonium compound site or an anion exchange resin having a chlorine-type quaternary ammonium salt site is used as a solid base, aldol condensation of aldehyde does not occur, and the resin has a hydroxyl group-type quaternary ammonium salt site. Only when using anion exchange resin,
They discovered the surprising fact that aldehydes selectively and quickly undergo aldol condensation with ketones to convert them into high-boiling compounds, and furthermore, they discovered that aldehydes can be converted into high-boiling compounds through aldol condensation with ketones.Furthermore, the anion exchange resin catalyst with this hydroxyl-type quaternary ammonium salt site can be used to reduce the amount of water present in ketones. The inventors have discovered that the catalyst has the advantage of a long lifespan because it does not dissolve and disappear, and has arrived at the present invention.

Therefore, the present invention is a method for purifying ketones, which comprises heating a crude ketone containing a trace amount of aldehyde in the presence of an anion exchange resin having a hydroxyl type quaternary ammonium salt site, and then distilling the crude ketone.

The anion exchange resin having a hydroxyl type quaternary ammonium salt site used in the present invention is N-(CH3)2
(CH2CH20H)OH1N3(CH3)30H, has a three-dimensional giant network structure, and is an anion exchange resin generally known as MR type resin. Amberlyst A-29, A-26 , A-27
, Amberlite IRA-9001IRA-910 and other registered trademarks.

Particularly preferred among these is -N3(CH3)30H
These are anion exchange resins having the sites shown by, ie, Amberlyte [F] A-26, A-27 and Amberlyte [F] IRA-900.

In the present invention, the heating of the ketone for aldol condensation of the aldehyde is carried out at a temperature of 80° C. or lower, taking into account the maximum operating temperature of the anion exchange resin.

Heating may be done in a batch or continuous manner, and may be done in a fixed bed or a mixing tank.

After carrying out the process of the present invention, the ketone is purified by distillation, the ketone being recovered from the top of the column and the aldol condensation product from the bottom of the column.

The crude ketone used in the present invention is obtained by the cumene method and contains a trace amount of impurity aldehyde, and as a result of implementing the present invention, the aldehyde content in the ketone is, for example, 200 p
pm can be reduced to 10 ppm or less.

Of course, the present invention is applicable not only to crude acetone obtained by the cumene method but also to methyl ethyl ketone, methyl isobutyl ketone, and the like.

By carrying out the present invention, ketones with extremely low aldehyde content can be obtained, with no loss of catalyst (and with little increase in utility due to the use of anion exchange resins), and with reduced chemical oxygen demand of the waste water from the ketone distillation purification column. It has the advantage that it does not become expensive.

Examples 1 to 5, Comparative Examples 1 to 3 500 ml of crude acetone containing 80 ppm of isobutyraldehyde and 10 rnl of water were placed in a flask equipped with a stirrer, a thermometer, a condenser, and a sampling port, heated to reflux, and then A catalyst as shown in was added and heating at reflux continued for 120 minutes.

The heated acetone is passed through an Aldershaw distillation column (20 stages).
Batch distillation was carried out, and the entire amount of acetone with a boiling point of 56.5°C was recovered in the initial distillation.

Table 1 shows the ratio of high boilers to crude acetone and the isobutyraldehyde content of this acetone.

Example 6 90 ppm of isobutyraldehyde was added to the same apparatus as in Example 1.
500 ml of crude acetone, 50 ml of water, and 5 ml of toluene were added and heated under reflux, and then 251 of Amberlite IRA-900 (a hydroxyl type quaternary ammonium salt site) was added, and the reaction was continued for 120 minutes.

After the reaction, distillation was carried out in the same manner as in Example 1, and acetone containing 2 ppm of isobutyraldehyde was recovered.

The high boiling point content was 3%. Examples 7-8
E* A packed bed with a jacket (inner diameter 19.5 mm) for flowing hot water is erected vertically, and
Filled with 0m1 of Amberlite IRA-900 (hydroxyl type quaternary ammonium salt site) (height 300mm) L
In a fixed bed, crude acetone containing 10,100 pp of isobutyraldehyde and a water content of 26 wt% was continuously passed from below to above under the conditions shown in Table 2.

500 ml of the product liquid was distilled in the same manner as in Example 1, and the results are shown in Table 2.

Example 10 In the same manner as in Example 7, crude acetone containing 170 ppm of acetaldehyde, 40 ppm of propionaldehyde, 50 ppm of isobutyraldehyde, and a water content of 1.4 wt% was passed under the conditions of 54° C. and a space velocity of 13.3 hr'.

The aldehyde content of the acetone recovered by distillation in the same manner as in Example 1 was <5 ppm for acetaldehyde and <1 ppm for propionaldehyde and isobutyraldehyde.

The high boiling point content was 3.6%.

Claims (1)

[Scope of Claims] 1. A method for purifying a ketone, which comprises heating a crude ketone containing a trace amount of aldehyde in the presence of an anion exchange resin having a hydroxyl type quaternary ammonium salt site, and then distilling the crude ketone. 2. The method according to claim 1, wherein the crude ketone is crude acetone obtained by the cumene method. 3. The method according to claim 1, wherein the anion exchange resin has a site represented by -Nmi(CH3)30H. 4. The method according to claim 1, wherein the heating temperature is 80° C. or lower.