JPS6256448A - Separation of highly concentrated hydroxyacetone - Google Patents

Abstract

PURPOSE:To separate the titled compound in high concentration from a crude phenol produced by the acid catalytic decomposition of a hydroperoxide, by carrying out the extractive distillation of the crude phenol in the presence of a polyalkylene glycol, etc., having higher boiling point than phenol, and distilling the column top fraction separated from the column bottom residue. CONSTITUTION:A crude phenol separated from a product produced by the acid catalytic decomposition of a hydroperoxide is subjected to the extractive distillation in the presence of a polyalkylene glycol or its ether having higher boiling point than the phenolic compound. The column top fraction separated from the column bottom residue (containing phenol and polyalkylene glycol or its ether) and containing hydroxyacetone is distilled to separate hydroxyacetone in high concentration. Preferably, the distillation is carried out by adding about 0.1-50wt%, preferably about 0.5-5wt% water to the column top fraction. EFFECT:Useful hydroxyacetone which cannot be produced on industrial scale can be separated in high concentration.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for separating high concentration hydroxyacetone. More specifically, the present invention relates to a method for separating hydroxyacetone, which is produced as a by-product during the production of phenols from acid-catalyzed decomposition products of hydroperoxides, at a high concentration.

[Conventional technology]

Hydroxyacetone-containing waste liquid, which is produced as a by-product when producing phenols from acid-catalyzed decomposition products of hydroperoxides, is distilled at a bottom temperature of 90 to 150°C while maintaining acidic conditions to recover hydroxyacetone at a high concentration. This is described in Japanese Unexamined Patent Publication No. 144310/1983.

However, this method is limited to concentration from an aqueous solution because it concentrates from a hydroxyacetone-containing waste liquid, and as mentioned above, it requires adjustment of ρ11, restrictions on distillation temperature, etc. The concentration is 1.
It can only be concentrated to about 7% to 16%.

[Problem that the invention seeks to solve]

On the other hand, conventionally, crude phenols obtained from acid-catalyzed cracking products of hydroperoxides are subjected to extractive distillation in the presence of polyalkylene glycol or its ether having a higher boiling point than the phenols, and the bottom fraction is converted into phenols. A method of obtaining crude phenols by separating polyalkylene glycol or its ether is known (Japanese Patent Publication No. 36-5713, No. 58-1441).
1), even in the case of such a method, various methods have been studied to separate by-produced hydroxyacetone to a high concentration, and as a result, by distilling the hydroxyacetone-containing top fraction separated from the bottom fraction. , it was found that the intended purpose was achieved.

[Means for Solving the Problems] and [Operations] Accordingly, the present invention relates to a method for separating highly concentrated hydroxyacetone, in which the separation of highly concentrated hydroxyacetone is performed using a crude product obtained from acid-catalyzed decomposition products of hydroperoxides. Hydroxyacetone-containing overhead fraction separated from the bottom fraction containing phenols and polyalkylene glycol or its ether by extractive distillation of phenols in the presence of polyalkylene glycol or its ether having a higher boiling point than the phenols. This is done by distilling the

After catalytic cracking of a hydroperoxide such as cumene hydroperoxide with an acid and neutralization of the acid in the generated acid cleavage product, unreacted substances, acetone as a by-product, and a lower boiling point fraction 1 reaction solvent In order to fractionate water, etc., and further remove substances with higher boiling points than phenols as necessary, approximately 0% of the phenols contained in the crude phenols are removed.
．． Purified phenols are obtained by distilling a phenol fraction of 1 to 50% by weight, and extractively distilling the obtained crude phenols in the presence of a polyalkylene gelylcol or its ether having a higher boiling point. The top fraction containing impurities during this extractive distillation contains hydroxyacetone as a by-product.

That is, the top fraction contains phenol and cumene.

In addition to α-methylstyrene, water, etc., several thousand pp+s
It contains about 10% of hydroxyacetone.

When such a hydroxyacetone-containing overhead fraction is distilled under normal pressure to increased pressure or reduced pressure under conditions such that hydroxyacetone does not decompose or polymerize.

A high concentration of hydroxyacetone is obtained as an overhead fraction. At this time, the top fraction is hydroxyacetone.

Preferably, the distillation operation is carried out under conditions that result in hydrocarbon components and water. In other words, when distilled under these conditions, the distillate components undergo phase separation.

Due to the difference in the distribution coefficients of hydroxyacetone to hydrocarbon components and water, a higher concentration of hydroxyacetone can be obtained as an aqueous solution. Therefore, if no water or only a trace amount of water is present in the impurity-containing overhead fraction subjected to the distillation operation, about 0.1 to 50% by weight of water is preferably added to the overhead fraction. is about 0.5
It is desirable to add and distill it so that it coexists in an amount of about 5% by weight.

〔Effect of the invention〕

Hydroxyacetone is a raw material for dyes, pyruvic acid, and other useful substances, but there is currently no way to produce it on an industrial scale. On the other hand, if hydroxyacetone, which is a by-product when producing phenols by the cumene method, is mixed in the phenol product, it may cause undesirable coloration when the phenol is sulfonated with sulfuric acid or treated with Shiohiro. Therefore, hydroxyacetone must be removed.

However, the method of the present invention effectively removes hydroxyacetone as an undesirable by-product from phenols, and also produces useful hydroxyacetone, for which there is no acquisition route on an industrial scale, at a higher concentration than in the prior art. In particular, in the coexistence of water, it is separated at a high concentration of about 50-75%,
It is possible to achieve the effect of killing two birds with one stone.

〔Example〕

Next, the present invention will be explained with reference to examples.

Example 1 Crude phenol obtained from the acid catalytic cracking product of cumene hydroperoxide was subjected to extractive distillation in the presence of diethylene glycol, yielding a mixture of phenol and diethylene glycol as a bottom fraction and a hydroxyacetone-containing fraction as an overhead fraction. Each fraction was obtained.

The raw material obtained by adding water to this hydroxyacetone-containing fraction and adjusting the water content to 1.1% was placed in sieve tray #2.
0 distillation column at a flow rate of 1375 g/hr,
Distillation under reduced pressure was carried out under the conditions of a pressure of 150 mmHg, a tower top temperature of 100 to 150°C, and a tower bottom temperature of 130 to 135°C, and the extract was taken out at a flow rate of 327 g/hr. This extract was allowed to stand and was separated into a hydroxyacetone phase and an oil phase.

First surface water 1.1 17.6
0.4 0.0 Hydroxyacetone 5,2
68.0 g, 7 0.1
charcoal seven;
．． 6 88,4 24.6 Phenol 56.3 7.8
7,5 75.2 Example 2 In Example 1, a raw material prepared by adding water to the hydroxyacetone-containing fraction to adjust the water content to 2.0% by weight was used.

2nd surface water 2.0 33.8
0.5 0.0 Hydroxyacetone 5.2
51.5 5.6 0.4 Hydrocarbon acid content 37.0 ”7.6
89.7 8.7 Phenol 55.
8 7.1 4.2 90.
9 Example 3 In the same process as in Example 1, a raw material prepared by adding water to a hydroxyacetone-containing fraction to adjust its water content to 0.5% by weight was used.

(Left below) 3rd surface water 0.5 21.6
0.8 0.0 Hydroxyacetone 5,5
73,6 12.5 0.3α
-Methylstyrene 42.6 2.9
77.4 18.1 Phenol 45.
4 1.9 2.7 73.
1 Others 6.0 0.0
6.6 8.5 Example 4 In a process similar to Example 1, which is different from Example 3, a raw material was used in which water was added to the hydroxyacetone-containing fraction to adjust the water content to 0.5% by weight. .

(Left below) 4th surface water 0.5'35.4
0.5 0.0 Hydroxyacetone 2,
2 62.7 8.0 0.0
α-Methylstyrene 47.8 0.8
78.3 28.0 Phenol 37
．． 6 1.1 2-9 58
．． 3 Others 11.9 '0.0
+, 0.3 13.7 Example 5 (Comparative Example) In the same process as in Example 1, the hydroxyacetone-containing fraction was used as it was as a raw material.

Table 5 Charge liquid Top liquid Bottom liquid IJ' ■L[u ULlu Onboard UL ship Hydroxyacetone 8,2 24.9 4.3α-Methylstyrene 13,6 63.2 2.0 Phenol 75.0 3 .4 91.7 Others 3.2 8.5 From the results above 2.0, the following can be said.

(1) When hydroxyacetone is distilled in the coexistence of water, almost all of it is contained in the top fraction, and almost all of it is contained in the bottom fraction.

(2) Hydroxyacetone, which was contained only 2 to 8% by weight in the raw material fraction, is concentrated to about 50 to 75% by weight in the hydroxyacetone phase of the tower top liquid, and This shows that there is no loss due to decomposition or weighting.

(3) Looking at the results of Example 5 (control example), hydroxyacetone also migrated into the bottom fraction, albeit in a small amount.
On the other hand, it can be seen that the degree of concentration in the column fraction is low. When a small amount of water is added to the top liquid obtained here, the hydroxyacetone transferred to the bottom fraction can no longer be recovered, but the partition coefficient of hydroxyacetone to water is Since the distribution coefficient is significantly different from that of hydroxyacetone, most of the hydroxyacetone can be easily separated by phase separation of the oil-water layer.

Claims (1)

[Claims] 1. Crude phenols obtained from acid catalytic decomposition products of hydroperoxides are subjected to extractive distillation in the presence of polyalkylene glycol or its ether having a higher boiling point than the phenols, and the phenols and polyalkylene A method for separating high-concentration hydroxyacetone, which comprises distilling a hydroxyacetone-containing overhead fraction separated from a column bottom fraction containing glycol or its ether. 2. A method for separating high-concentration hydroxyacetone according to claim 1, which is applied to a hydroxyacetone-containing overhead fraction containing water. 3. The method for separating high-concentration hydroxyacetone according to claim 1, wherein water is added to the hydroxyacetone-containing overhead fraction and distilled. 4. The method for separating high-concentration hydroxyacetone according to claim 2 or 3, which is applied to a hydroxyacetone-containing overhead fraction in which about 0.5 to 5% by weight of water coexists.