JPH09169751A - Recovery of propylene oxide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To recover the subject compound useful as a raw material, etc., for polyurethane in high yield by reacting ethylbenzene hydroperoxide with propylene, mixing an amine compound with the resultant reaction solution and distilling the reaction solution. SOLUTION: (B) Ethylbenzene hydroperoxide is reacted with (C) propylene in the presence of (A) an epoxidizing catalyst consisting essentially of a molybdenum compound (A1 ) to afford a reaction solution containing propylene oxide(PO) and (D) an amine compound (e.g. tert-amine compound having >=150 deg.C boiling point such as tributylamine, trioctylamine, N,N-diethylaniline or quinoline or a water-soluble tert-amine compound such as 2-dimethylaminoethanol, 3- dimethylaminopropanol, 2-diethylaminoethanol or triethanolamine) in an amount of 0.5-10mol based on 1mol A1 is added to the reaction product and the reaction solution is distilled.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for recovering propylene oxide. More specifically, the present invention provides propylene from an epoxidation reaction liquid containing propylene oxide obtained by subjecting ethylbenzene hydroperoxide and propylene to an epoxidation reaction in the presence of an epoxidation catalyst containing a molybdenum compound as a main component. The present invention relates to a method for separating and recovering propylene oxide, which relates to a method for recovering propylene oxide in which the loss of propylene oxide accompanying a recovery operation is suppressed to a low level. Propylene oxide is a useful compound used as a raw material for polyurethane production.

[0002]

As a method for obtaining propylene oxide,
In U.S. Pat. No. 3,351,635, ethylbenzene is oxidized to give ethylbenzene hydroperoxide, and the ethylbenzene hydroperoxide is subjected to an epoxidation reaction with propylene in the presence of an epoxidation catalyst to obtain propylene oxide. Is disclosed. Here, in the epoxidation reaction liquid obtained by the epoxidation reaction, various by-products are contained in addition to the target propylene oxide and unreacted propylene. As a method for separating and recovering propylene and propylene oxide from such an epoxidized liquid,
A method using a distillation operation consisting of multiple steps, a method of washing the epoxidation liquid with an aqueous sodium hydroxide solution, and then distilling the same are known. However, when the epoxidation reaction liquid is subjected to distillation, there is a problem that the target product propylene oxide is lost. Further, when the method of washing with an aqueous solution of sodium hydroxide is used, in addition to the problem that propylene oxide is lost, water is mixed in the obtained propylene oxide, and propylene oxide is further lost during distillation for removing the water. There is a problem.

[0003]

In view of the above situation, an object of the present invention is to subject ethylbenzene hydroperoxide and propylene to an epoxidation reaction in the presence of an epoxidation catalyst containing a molybdenum compound as a main component. A method for separating and recovering propylene and propylene oxide from an epoxidation reaction liquid containing propylene oxide obtained by the method, wherein a propylene oxide recovery method in which loss of propylene oxide due to recovery operation is suppressed to a low level is provided. It depends on what you do.

[0004]

That is, the present invention contains a propylene oxide obtained by subjecting ethylbenzene hydroperoxide and propylene to an epoxidation reaction in the presence of an epoxidation catalyst containing a molybdenum compound as a main component. A method for separating and recovering propylene and propylene oxide from an epoxidation reaction solution,
The present invention relates to a method for recovering propylene oxide by adding an amine compound to the epoxidation reaction liquid and distilling it.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, an epoxidation reaction containing propylene oxide obtained by subjecting ethylbenzene hydroperoxide and propylene to an epoxidation reaction in the presence of an epoxidation catalyst containing a molybdenum compound as a main component. A liquid is used.

The epoxidation catalyst is a homogeneous catalyst containing a molybdenum compound as a main component. In this case, the amount of catalyst is adjusted so that 0.001 to 0.1% by weight of molybdenum is usually contained in the epoxidation reaction liquid. Examples of the epoxidation reaction method include a method in which propylene is blown into liquid ethylbenzene hydroperoxide containing an epoxidation catalyst and the reaction is carried out at a temperature of 40 to 150 ° C. and a pressure of 10 to 50 atmospheres. In addition, as the ethylbenzene hydroperoxide as a raw material, one obtained by oxidizing ethylbenzene is usually used. In the epoxidation reaction liquid thus obtained, in addition to 5 to 20% by weight of the desired product, propylene oxide and 5 to 50% by weight of unreacted propylene, ethylbenzene, 1-phenylethanol,
A trace amount of acetophenone, water and organic acids such as formic acid, acetic acid and propionic acid are contained. Here, the content concentration of water is usually 0.01 to 1% by weight, and the total content concentration of organic acids such as formic acid, acetic acid, and propionic acid is usually 0.005 to 0.
1% by weight.

The method of the present invention comprises adding an amine compound to the above epoxidation reaction solution and distilling it.

As the amine compound, a nitrogen-containing organic compound which is alkaline in water can be used. These include aliphatic or aromatic primary amines, secondary amines and tertiary amines. In addition, pyrroles, pyrrolidines,
Also included are nitrogen-containing heterocyclic compounds such as pyridines, piperidines, morpholines, quinolines. Of these,
Tertiary amines are preferred because they are inactive against the active ingredient in the epoxidation reaction solution. In addition, the third boiling point of 150 ℃ or more
The primary amine is preferable because it can be easily separated by distillation in the latter stage of propylene oxide and ethylbenzene. Specific examples thereof include tributylamine, tripentylamine, trihexylamine, trioctylamine, N, N
-Diethylaniline, quinoline and the like. Further, when there are steps such as caustic washing, acid washing, and water washing in the latter stage, a water-soluble tertiary amine which is easy to partition into the water phase is desirable. Specific examples thereof include 2-dimethylaminoethanol, 3-dimethylaminopropanol and 2-dimethylaminopropanol.
Examples thereof include amino alcohols such as diethylaminoethanol and triethanolamine.

The amount of these amine compounds added is preferably 0.5 to 10 times mol relative to 1 mol of the molybdenum compound present in the system. If the amount added is too small, the effect of suppressing the loss of the active ingredient during distillation will be low, and if too large, separation in the subsequent stage will be troublesome.

The following conditions can be given as conditions for distillation. The tower bottom temperature is preferably 100 to 180 ° C,
110-160 degreeC is more preferable. If the bottom temperature is too high, the loss of propylene oxide may increase, while if the bottom temperature is too low, propylene and / or
Alternatively, it becomes difficult to condense propylene oxide and is difficult to industrially adopt. The distillation pressure is usually 1 to 40 atm, and preferably 3 to 30 atm. Usually, propylene and / or propylene oxide is recovered from the top of the column and a bottom liquid containing active ingredients such as ethylbenzene, 1-phenylethanol and acetophenone is recovered from the bottom of the column by a plurality of distillation operations under the above conditions. To be done. The bottom liquid component is subjected to distillation separation as it is or after being subjected to caustic washing treatment with an alkaline aqueous solution to remove contained acid components and phenol. The ethylbenzene separated by distillation is recycled as it is or after purification to the oxidation step. 1-Phenylethanol is dehydrated to form styrene, which becomes a product after purification. Also, acetophenone is converted to 1-phenylethanol by hydrogenation and becomes styrene by dehydration.

[0011]

The present invention will be described in detail with reference to the following examples. The following abbreviations are used: PO: Propylene oxide EB: Ethylbenzene MBA: 1-phenylethanol ACP: Acetophenone

Example 1 Epoxidation reaction solution (31% by weight of propylene, PO 1
1% by weight, EB 32% by weight, MBA 17% by weight, A
CP 3% by weight, H ₂ O 0.1% by weight, formic acid, acetic acid,
A raw material obtained by adding 0.008% by weight of tributylamine to 0.01% by weight of propionic acid and 0.004% by weight of molybdenum was distilled. The added tributylamine equivalent is 1 mol per mol of molybdenum. At a column top pressure of 18 atm, a column bottom temperature of 150 ° C., and a residence time of 30 minutes at the column bottom (including a reboiler), most of propylene was collected from the column top, and PO, EB, MBA, and ACP were collected from the column bottom. . The loss of PO during the main distillation is due to the loss of PO in the raw material.
Was 0.1%.

Example 2 0.012 triethanolamine as an amine compound
The experiment of Example 1 was repeated except that the raw material added was wt%. The added triethanolamine equivalent is twice the molar amount of molybdenum. The loss of PO during distillation is due to the loss of P in the raw material.
It was 0.1% with respect to O.

Comparative Example 1 The same distillation as in Example 1 was carried out without adding tributylamine. The loss of PO was as large as 0.7%, and an adduct of PO and MBA was detected as a degradation product.

[0015]

As described above, according to the present invention, an epoxy resin containing propylene oxide obtained by subjecting ethylbenzene hydroperoxide and propylene to an epoxidation reaction in the presence of an epoxidation catalyst containing a molybdenum compound as a main component. A method for separating and recovering propylene and propylene oxide from a chlorination reaction solution,
It was possible to provide a method for recovering propylene oxide in which the loss of propylene oxide accompanying the recovery operation was suppressed to a low level.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number in the agency FI Technical display location // C07B 61/00 300 C07B 61/00 300

Claims (7)

[Claims] 1. Propylene and propylene oxide are obtained from an epoxidation reaction liquid containing propylene oxide obtained by subjecting ethylbenzene hydroperoxide and propylene to an epoxidation reaction in the presence of an epoxidation catalyst containing a molybdenum compound as a main component. A method for separating and recovering, wherein the method comprises recovering propylene oxide by adding an amine compound to the epoxidation reaction solution and distilling. 2. The recovery method according to claim 1, wherein the amine compound is a tertiary amine compound. 3. The boiling point of the amine compound under atmospheric pressure is 150 ° C.
The above is the recovery method according to claim 2. 4. The recovery method according to claim 2, wherein the amine compound is water-soluble. 5. The method according to claim 1, wherein the amine compound is tributylamine, tripentylamine, trihexylamine, trioctylamine, N, N-diethylaniline or quinoline. 6. The recovery method according to claim 1, wherein the amine compound is 2-dimethylaminoethanol, 3-dimethylaminopropanol, 2-diethylaminoethanol or triethanolamine. 7. The addition amount of the amine compound is 0.5 to 10 relative to 1 mol of the molybdenum compound which is the epoxidation catalyst.
The method according to claim 1, wherein the recovery method is molar.