JPH107607A - Separation of phenol from 1-phenylethanol, acetophenone or mixture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce problems in disposal of used caustic wastes and economically separate phenol from a mixture by carrying out the extractive distillation of the mixture, etc., produced by an oxirane propylene oxide/styrene monomer process with sulfolane. SOLUTION: The extractive distillation of (A) (A2 ) 1-phenylethanol or (A3 ) acetophenone containing a contanimating amount of (A1 ) phenol or a mixture thereof is carried out by using (B) a sulfolane extractive distillation agent effective in reducing the volatility of the component A1 as compared with those of the components A2 , and A3 in an extractive distillation column 1 to separate the components A2 and A3 from the component A in the column top of the extractive distillation column 1. The separated components A2 , and A3 are then taken out through a pipe 4 and the column bottom stream containing he components A1 and B is fed to a stripper 6 and distilled to separate the component A1 in the column top of the stripper 6. The separated component A1 is then recovered through a pipe 7. Furthermore, the component B is preferably pretreated with a basic ion exchange resin for use.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for separating phenol from a phenol-containing stream of 1-phenylethanol and / or acetophenone by extractive distillation. Oxirane process for producing propylene oxide and styrene monomers together (Oxirane proc)
In ess), propylene is reacted with ethylbenzene hydroperoxide to form propylene oxide and methylbenzyl alcohol (1-phenylethanol), which is dehydrated to form styrene. Significant amounts of phenol are formed, which are separated according to the invention from methylbenzyl alcohol and the accompanying acetophenone by extractive distillation using sulfolane as extractive distillation solvent.

[0002]

BACKGROUND OF THE INVENTION A very successful process for producing both propylene oxide and styrene monomers is the oxidation of ethylbenzene with molecular oxygen to form ethylbenzene hydroperoxide, which catalyzes the hydroperoxide with propylene. Reacted with propylene oxide and 1
Forming phenylethanol and dehydrating the 1-phenylethanol to styrene monomer. The basic patent describing this method is U.S. Pat.
No. 351,635.

In this process, a stream is formed consisting of 1-phenylethanol and acetophenone which also contains a substantial amount of phenol. It is important that phenol be removed from the viewpoint of product purity and yield.

[0004] The separation of phenol is caustic (causti).
c) Can be effected by processing, but this results in the formation of a spent caustic waste stream, which represents an increasingly difficult problem of disposal. U.S. Pat. No. 5,171,868 provides a method by which the amount of spent caustic to be disposed of can be substantially reduced. However, further improvements would be advantageous. Separating a mixture of 1-phenylethanol, acetophenone and phenol by conventional distillation methods is not economical because of components having boiling points close to each other.

[0005]

SUMMARY OF THE INVENTION From a mixture of 1-phenylethanol, acetophenone and phenol, which is contained as an impurity in a significant amount, produced by the oxirane propylene oxide / styrene monomer method, comprising components having boiling points close to each other, It would be desirable to develop a method that successfully separates substantial amounts of phenol in a manner that does not involve conventional disposal problems and is not uneconomical, such as by conventional distillation.

[0006]

SUMMARY OF THE INVENTION Phenol can be separated from styrene precursors such as 1-phenylethanol and acetophenone by extractive distillation using sulfolane as an extractive distilling agent, thus reducing the amount of spent caustic. It has now been found that the problem of disposal can be greatly reduced.

In accordance with the present invention, styrene precursors containing contaminating amounts of phenol, including 1-phenylethanol, acetophenone, and mixtures thereof, are extractively distilled using sulfolane as the extractive distillation solvent, thus obtaining 1 -Reduces the volatility of phenol compared to phenylethanol and acetophenone, so that phenylethanol and acetophenone can be distilled overhead from the phenol-containing sulfolane solvent.

The mixture treated in accordance with the present invention generally comprises, by weight, about 0-99.9% 1-phenylethanol about 0-99.9% acetophenone and about 0.1-9% acetophenone.
Contains 01-50% phenol. Small amounts of other organic substances may also be present. Most advantageously, the mixture treated in accordance with the present invention is a mixture produced by the Oxirane propylene oxide / styrene monomer method and, by weight, comprises about 20-90% 1-
Phenylethanol, about 10-75% acetophenone,
It contains about 0.5-5% phenol and about 1-20% organic material.

[0009] The relative volatility of acetophenone, 1-phenylethanol and phenol are close enough that their effective separation by conventional distillation is unduly expensive. However, with the extractive distillation method of the present invention, the separation is conveniently effected in an efficient and cost-effective manner.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the accompanying drawings, a phenol-containing mixture to be purified is passed via a pipe 2 to an extractive distillation column 1.
Will be introduced. A sulfolane extractive distillation agent, ie, tetramethylene sulfone, is also introduced into column 1 in the upper section via line 3.

The effect of the extractive distillation agent is that the other major components of the mixture, 1-phenylethanol and / or
The volatility of the phenol is substantially reduced compared to acetophenone, so that 1-phenylethanol and acetophenone are separated overhead and removed via line 4. A bottoms stream containing a major amount of phenol is withdrawn via line 5 and passed to a stripper 6. In stripper 6 phenol is distilled overhead and recovered via line 7, while extractive distillate is separated as bottoms stream via line 3 and recycled to extractive distillation column 1.

By the practice of the present invention, substantially complete phenol separation can be achieved without the need for caustic treatment with the problem of caustic waste stream disposal.

[0013] Extractive distillation can be carried out in conventional distillation equipment under conventional conditions. Generally, distillation columns having from 10 to 30 theoretical stages can be used. Amounts of sulfolane in the range of about 50-200% by weight of the phenol containing feed are suitable.

The distillation of the 1-phenylethanol / acetophenone composition from the sulfolane mixture is carried out at a pressure of 10 to 760 mmHg in column 1 of the drawing. The temperature at these pressures is 82.22 to 198.9 ° C (180 to 3
90 ° F.). Preferably, the pressure is 82.2
It is in the operating range of 10 to 30 mm Hg using temperatures in the top range of 2 to 107.22 ° C (180 to 225 ° F).

When removed from the extractive distillation column, the phenol and sulfolane are stripped to separate phenol at the top and the sulfolane at the bottom is recycled to the extractive distillation column. The top condition of the tower is 10 to 760 mmHg and 8
180 ° -390 ° F. (2.22-198.9 ° C.). Preferably, the pressure is between 82.22 and 104.44 ° C.
(180-220 ° F.) at a top range of 10-30
within the operating range of mmHg.

The bottom temperature of the two columns is dictated by the pressure drop in the system and the bubble point of the bottom composition, and the stripper column reboiler has a higher overall temperature compared to the extractive distillation column reboiler at the same bottom pressure. Operate with.

Sulfolane, as commonly provided, contains acidic impurities which tend to catalyze the dehydration of 1-phenylethanol during extractive distillation. To avoid this,
Before using sulfolane in extractive distillation,
It is particularly advantageous to first treat the sulfolane with a basic ion exchange resin such as Amberlyst A-21 from m & Haas. Amberlyst is a registered trademark of Rohm & Haas. Table 1 below
As can be seen, treatment with a basic ion exchange resin, as indicated by the pH of the 50/50 weight mixture of water and treated sulfolane, is effective in removing acidic components.

[0018]

[Table 1]

In an advantageous basic ion exchange resin treatment, liquid sulfolane is contacted with the solid resin at 30-70 ° C. Generally, treatment with four volumes of resin per volume of sulfolane is sufficient. If the activity is substantially reduced, the resin can be regenerated by treatment with a base such as NaOH.

[0020]

The following examples illustrate the invention.

Referring to the accompanying drawings, the oxirane method (Ox
24.8% by weight from irane process)
453.59 kg of a mixture of 1-phenylethanol, 59.8% by weight acetophenone, 3.1% by weight phenol, and 13.3% by weight of other organics
Per hour (1000 pounds / hour) via line 2 to extractive distillation column 1 (this column comprises 18 theoretical plates).
feed to this column 1 near the midpoint). In addition, sulfolane is supplied through pipe 3 to 45
Feed into tower 1 near the top of tower 1 at a rate of 3.80 kg / hr (100.47 lb / hr). The sulfolane was a basic ion exchange resin A-21 from Rohm & Haas, which had been treated to a pH of 7.33.

In column 1, acetophenone and 1-
Phenylethanol is extractively distilled from phenol and via line 4 453.39 kg / hr (999.56
(Lb / hr) at a rate of 192 ° F (88.89 ° C) and 20 mmHg. The withdrawn 1-phenylethanol and acetophenone stream contains 0.3% by weight of phenol, 24.8% by weight of 1-phenylethanol, 58.9% by weight of acetophenone and 0% by weight of sulfolane and oxirane (Ox
This is a suitable feed stream to the styrene production section of the irane plant.

The bottom stream consisting of sulfolane and phenol is supplied via a pipe 5 to 466.54 kg / hr (102
8.541 pounds / hour) at 204.44 ° C (4
00 ° F) and 90 mmHg. This stream contains 0% by weight of 1-phenylethanol, 0% by weight of acetophenone, 2.7% by weight of phenol, 0.1% by weight.
Containing 97.7% by weight of sulfolane and passed through line 5 to stripper 6. 11
In stripper 6 with the theoretical stages of 12.79 k overheads
85 ° C. at a rate of g / hr (28.20 pounds / hr)
(185 ° F.) and 20 mmHg. This stream comprises 0.9% by weight of 1-phenylethanol,
It contains 0.1% by weight of acetophenone, 98.9% by weight of phenol, 0% by weight of other organic substances and 0.1% by weight of sulfolane.

Sulfolane was used as a bottom at 193.33 ° C.
(380 ° F.) and 65 mmHg and is recycled to extractive distillation column 1 via line 3 as described above. Supplementary extractive distillation agent is added as needed (not shown).

The present invention provides a convenient and effective method for the separation of phenol from 1-phenylethanol and / or acetophenone and thus provides a viable alternative to conventional caustic treatment methods. It can be seen from the above examples.

[Brief description of the drawings]

FIG. 1 is a diagram schematically illustrating the implementation of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Extraction distillation tower 2 Pipe 3 Pipe 4 Pipe 5 Pipe 6 Stripper 7 Pipe

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication C07C 49/78 8114-4H C07C 49/78 (72) Inventor Stephan H. Harris United States of America Pennsylvania 19348 Kennett Square Saltner Driving 104 (72) Inventor Thomas E. Zach USA Pennsylvania 19382 West Chester Plumley Road 1016 (72) Inventor Te Chan USA Pennsylvania 19382 West Chester Shawmont Drive 839

Claims (5)

[Claims] 1. Extractive distillation of a phenol-containing stream of 1-phenylethanol and / or acetophenone using a sulfolane extractive distilling agent effective to reduce the volatility of phenol compared to 1-phenylethanol and acetophenone. Separating phenol from 1-phenylethanol, acetophenone or a mixture thereof by separating phenol-depleted 1-phenylethanol and acetophenone at the top of the column and recovering phenol from the extractive distillation agent by distillation. how to. 2. The method of claim 1, wherein the sulfolane has been pre-treated by contacting with a basic ion exchange resin. 3. A method for removing acidic impurities from sulfolane, which comprises contacting sulfolane containing acidic impurities with a basic ion exchange resin. 4. The mixture of 1-phenylethanol and acetophenone from the propylene oxide and styrene monomer process is extractively distilled from phenol.
The method described in. 5. The process according to claim 1, wherein the sulfolane extractive distillation agent is used in an amount of 50-200% by weight of the phenol-containing stream of 1-phenylethanol and / or acetophenone.