JPS62164636A - Recovery of useful substances from phenol distillation residue - Google Patents

Abstract

PURPOSE:In the production of phenol and acetone by oxygen oxidation of cumene, the distillation residue is pyrolyzed in the presence of a specific silica- alumina catalyst to recover useful substances such as cumene, phenol or the like. CONSTITUTION:Cumene is oxidized with oxygen into cumene hydroperoxide and the peroxide is pyrolyzed and phenol and acetone are separated by distillation from the reaction mixture. Then, the distillation residue is pyrolyzed at 200-310 deg.C, preferably 250-300 deg.C in the presence of an aluminum catalyst (in the form of powder or pellets) which is selected from aluminum sulfate, aluminum phenoxide and a silica-alumina catalyst in which the ratio of Al2O3:SiO2 is 99/1-60/40 and the specific surface area is over 50m<2>/g to recover useful substances such as alpha-methylstyrene, phenol, cumene or acetophenone. The polymerization of acetophenone can be inhibited.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for producing cumene, α-methylstyrene, This invention relates to a method for recovering useful substances such as phenol in high yield.

Technical Background and Problems Phenol is a compound widely used as a synthetic intermediate for synthetic resins, surfactants, pharmaceuticals, etc. Various methods are known as such N3B methods for phenol. Among them, cumene is oxidized with oxygen to synthesize cumene hydroperoxide, and this cumene hydroperoxide is decomposed with acid to produce phenol and acetone. The Kumen method is mainly practiced.

By the way, when phenol is produced by the cumene method by oxidation of men with oxygen as described above, by-products such as dimethylphenyl carbinol, α-methylstyrene, α-methylstyrene, and cumylphenol are produced. In addition to phenol and acetone, the above-mentioned by-products are present in the reaction mixture that is released after the reaction. Therefore, the distillation residue obtained after distilling and separating phenol and acetone from such a reaction mixture (hereinafter sometimes referred to as phenol distillation residue) contains dimethylphenol carbinol, acetophenone,
Large amounts of by-products such as α-methylstyrene and α-methylstyrene derivatives are present. Converting and recovering this by-product into a useful substance is extremely important in reducing the cost of producing phenol by the cumene method.

Conventionally, useful substances such as cumene, α-methylstyrene, phenol, and acetophenone have been recovered from the phenol distillation residue by thermally decomposing the phenol distillation residue and then distilling the residue.

However, the conventional method of thermally decomposing phenol distillation residue without using a catalyst has the problem that decomposition takes a long time and the recovery rate of cumene, α-methylstyrene, phenol, acetophenone, etc. is low.

In order to solve and overcome these problems, the special public
Publication No. 92 states that when producing phenol by the cumene method, an alumina-based catalyst such as γ-alumina or a silica-alumina-based catalyst such as silica-alumina, acid clay, or synthetic zeolite is used to thermally decompose the residue obtained by distilling phenol and acetone. Disclosed is a method for recovering useful substances such as cumene, α-methylstyrene, and phenol from phenol distillation residue, which is characterized by thermal decomposition in the presence of a catalyst or in the coexistence of these catalysts and an acid. .

However, according to an example specifically disclosed in Japanese Patent Publication No. 59-36892, the silica alumina catalyst has a ratio of A1203 to SiO2 of 10:90 to 50.
: 50 is used, and the reaction temperature is ultimately heated to 340-345°C, so dimethylphenyl carbinol ren dimer, A-rutocumylphenol, paracumylphenol The recovery rate of α-methylstyrene from
Although the recovery rate of phenol was as high as 0%, it was found that the recovery rate of phenol was extremely low at 3 to 30%, and that there was a further problem in that acetophenone, which is a useful substance, became heavy during the reaction.

Purpose of the Invention The present invention aims to solve the problems associated with the above-mentioned prior art, and involves synthesizing cumene hydroperoxide by oxidizing cumene with oxygen, and then decomposing the cumene hydroperoxide with acid to produce phenol. 1 when preparing with acetone
To provide a method by which useful substances such as cumene, phenol, α-methylstyrene, or acetophenone can be recovered with a high recovery rate from a distilled residue obtained by distilling and separating phenol and avitone from a reaction mixture. It is an object.

The method of recovering useful substances from phenol distillation residue according to the present invention involves oxidizing cumene with oxygen to synthesize cumene hydroperoxide, and distilling phenol and acetone from the reaction mixture obtained by decomposing it with acid. The separated distillation residue was treated with aluminum sulfate, aluminum phenoxide, A12
In the presence of an aluminum catalyst selected from the group consisting of silica alumina catalysts with a ratio of 03 to SiO2 of 99:1 to 60:40 and a specific surface area of 5 (hyf/y or more), 2
It is characterized by carrying out the reaction at a temperature of 00 to 310°C and recovering useful substances such as cumene and phenol.

According to the method for recovering useful substances from distillation residue according to the present invention, not only cumene and α-methylstyrene can be recovered from the distillation residue with a high recovery rate, but also phenol can be recovered with a high recovery rate, and the weight of acetophenone can be recovered with a high recovery rate. It is also possible to suppress quality formation, and therefore it can greatly contribute to cost reduction when producing phenol.

DETAILED DESCRIPTION OF THE INVENTION The method for recovering useful substances from distillation residue according to the present invention will be specifically described below.

The distillation residue to which the process according to the present invention is applied includes:
Cumene hydroperoxide is synthesized by oxidizing cumene with oxygen, and this is decomposed with acid to produce phenol and acetone. The distillation residue obtained by distilling and separating phenols and acetone from the 2+9 reaction mixture is used.

More specifically, when cumene is oxidized with oxygen to synthesize cumene hydroperoxide, which is separated with acid to produce phenol and acetone, phenol and acetone are extracted from the reaction mixture as shown in the following formula. The process according to the present invention is applied to the distillation residue obtained by distilling and separating phenol, cumene, α-methylstyrene, acetophenone, and other useful substances.

In the following description, the process according to the present invention will be explained in more detail.

Cumene hydroperoxide is synthesized by oxygen oxidation of cumene, and phenol and acetone are separated by distillation from the reaction mixture obtained by acid decomposition. Dimethylphenylcarbinol, α-methylstyrene, α-methylstyrene dimer, orthocumylphenol, paracumylphenol,
Contains large amounts of acetophenone or other high boiling products.

Dimethylphenylcal 03 In the method for recovering useful substances from distillation residue according to the present invention,
The phenol distillation residue containing such by-products is treated with aluminum sulfate, aluminum phenoxite, AI
2 03 Tos l 02 To (7) Ratio is 99:1 to 6
0:40 and a specific surface area of 50 Td/9 or more in the presence of an aluminum catalyst selected from the group consisting of silica arsina catalysts at 200 to 310°C, preferably at 250 to 30°C.
Thermal decomposition reaction is carried out at a temperature of 0''C.

The aluminum catalyst used in the present invention includes aluminum sulfate, aluminum fluorite, A1203 and sulfuric acid.
It is selected from the group consisting of silica alumina having a ratio with r 02 of 99:1 to 60:40 and a specific surface area of 50 Td/g or more. If a silica alumina catalyst having a ratio of A1203 to S i O2 outside the above range and a specific surface area of less than 50/g is used, it is not preferable because the recovery rate of α-methylstyrene and the recovery rate of phenol will be low. These aluminum catalysts are preferably used in the form of powder or pellets.

The thermal decomposition reaction of the phenol distillation residue in the presence of the above-mentioned aluminum catalyst may be carried out either batchwise or continuously. In the case of batch operation, the aluminum 1 cum catalyst mentioned above is 0.5 to 10% of the distillation residue.
fflff is used at a concentration of 1%, preferably 2-5%. Further, continuous operation may be carried out by either a fixed bed method or a fluidized bed method, in which case the superficial velocity of the catalyst per hour (L
HSV) is 0.

07 to 0.5Hr-1 preferably 0.08 to 0.25
Hr-1.

The thermal decomposition reaction of distillation residue can be carried out under reduced pressure, normal pressure, or 110 pressure, but usually 40
It is preferably carried out under normal pressure. The reaction time varies greatly depending on the reaction humidity, but is usually about 2 to 15 hours, preferably 4 to 12 hours.

When the distillation residue is thermally decomposed in the presence of the above-mentioned aluminum-based catalyst, the dimethylphenylcarbinol and α-methylstyrene contained in the distillation residue have a high selectivity. is converted to α-methylstyrene, i.e. dimethylphenylcarbinol is dehydrated and α-methylstyrene is converted to α-methylstyrene.
It becomes methylstyrene, and the ω-form of α-methylstyrene is depolymerized to become α-methylstyrene. Zarani O-
Cumylphenol and P-cumylphenol are decomposed into α-methylstyrene and phenol.

During the above thermal decomposition reaction, some of the hydrocarbons are carbonized and hydrogen is generated along with this.
A portion of methylstyrene becomes cumene.

In this way, when the distillation residue is thermally decomposed in the presence of the above aluminum-based catalyst, the by-products contained in the distillation residue are converted into useful substances such as α-methylstyrene, phenol, and cumene. , these useful substances are separated and recovered by methods such as distillation. When recovering the above-mentioned useful substances from the distillation residue, if it is desired to increase the amount of α-methylstyrene recovered, it is preferable to blow a small amount of nitrogen into the reaction system. Furthermore, if it is desired to increase the amount of cumene recovered, it is preferable not to blow nitrogen into the reaction system.

In the present invention, thermal decomposition of phenol heating residue in the presence of a mixed catalyst is carried out at a temperature of 310°C, preferably 300°C or lower, thereby increasing the recovery rate of acetophenone contained in the phenol distillation residue by 70%. You can increase it even more.

In addition, in the method disclosed in the above-mentioned Japanese Patent Publication No. 59-36,892@, the maximum thermal splitting temperature reaches 340-345°C, so the recovery rate of acetophenone contained in the noenol distillation residue is 50°C. It is about %.

Effects of the Invention According to the method for recovering useful substances from phenol distillation residue according to the present invention, not only cumene and α-methylstyrene can be recovered from the distillation residue at a high recovery rate, but also phenol can be recovered at a high recovery rate. In addition, it is possible to suppress acetophenone from becoming heavy, and therefore it can greatly contribute to cost reduction when producing phenol.

EXAMPLES The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples.

Example 1 Stirring device, cooling pipe, nitrogen inlet and temperature detector
In a 200 d four-bottle flask, 100 g of phenol distillation residue was obtained by distilling and separating phenol and acetone from the reaction mixture obtained by the cumene method (the phenol distillation residue contained 20.89 g of acetophenone, 6.8 g of dimebulphenyl carbinol, and 6.8 g of phenol). 19.'L, α-methylstyrene depleted body 10.4!iF, Δcytocumylphenol 3.9g, paracumylphenol 13.2g, unknown substance 2.29, and simple substance 22.89) were added, and powder was added. aluminum sulfate 5.09 (5,0
Shigenobu %) was added thereto, and the mixture was gradually heated while stirring, and finally heated to 290°C.

It took 8 hours to heat and the distillate was 11. During this time, nitrogen was fed into the flask at a rate of 509/min.

The distillate and the entire flask residue were mixed, and the catalyst was separated from 1q of the distillate mixture and analyzed by gas chromatography. The products were 2.9 g of cumene, 21.33 g of α-methylstyrene, and 21.33 g of α-methylstyrene. Acetonephenone 16.8g,
Dimethylphenyl carbinol 0.3g, phenol 2
5.29, α-methylstyrene 1.33, orthocumylphenol 1.53, paracumylphenol 1.
19, unknown substance 1.89, and heavy content 27.957.

Comparative Example 1 The method of Example 1 except that no catalyst was added.
The same procedure as in Example 1 was carried out.

The reaction products are 3.3 g of cumene and 10 g of α-methylstyrene.
．． 59. Acetophenone 17. (1, dimylphenyl carbinol 1.23, phenol 21.79, α-methylstyrene diisomer 1.19, orthocumylphenol 0.53, paracumylphenol 9.6g, unknown substance 3
．． 6g, and 31.5g of impurities.

Comparative Example 2 In the method of Example 1, the catalyst was synthetic zeolite [trade name: Molecular Sieve 5A (manufactured by UCC)] 59 (
The same procedure as in Example 1 was carried out except that the amount was changed to 5% by weight). Furthermore, this synthetic zeolite is composed of AIO and SiO2.
The old-to-old ratio was 50:50, and the sodium money was 20%, and the calcium money was 100%.

The reaction products are 3.19 cumene and 14 α-methylstyrene.
．． 1g, acetophenone 18.69, dimethylphenylcarbinol 0.13, phenol 21.59, α--
Methylstyrene 1.33, orthocumylphenol 1.99, paracumylphenol 9.99, unknown substance 1
．． 43, heavy material 28.1C].

Example 2 The same procedure as in Example 1 was carried out except that the catalyst was changed to aluminum phenoxide 5.0Q (5fflffi%).

The reaction products, excluding phenol derived from the catalyst, contained 3.59 g of cumene, 21.9 g of α-methylstyrene, 17.19 g of acetophenone, 3 g of dimethylphenylcarbinol, and 0.17 g of α-methylstyrene. , orthocumylphenol 0.23, paracumylphenol 1.29
, unknown substance 1.93, and heavy substance 27.7J.

Example 3 In the method of Example 1, the catalyst was a silica aluminum catalyst (A1203 90% Si022.0).
Vehicle assembly%, Na content less than 0.1 Shigenobu%, Ca content 0.

1% or less, specific surface area 280 butts/g, diameter 5-6mm
The same procedure as in Example 1 was conducted except that the catalyst was changed to spherical catalyst) 5Q (5% by weight).

The reaction products are 3.4 g of cumene and 19 g of α-medylsubrene.
．． 3Q, Azehif 1non 19.5q, dimethylphenylcarbinol 26.4CI, α-methylstyrene rod body 0 39
1 orthocumylphenol 0.3 (1, paracumylphenol 1.0g, unknown substance 1.2g, heavy substance 28.20
Met.

Comparative Example 3 In Example 1, the catalyst was a powdered silica/alumina catalyst (
Example 1 except that the reaction temperature was 340°C and the reaction time was 4 hours.
Thermal decomposition reaction of phenol distillation residue was carried out in the same manner as above.

The reaction products are cumene 7,03, α-methylstyrene 17
．． 9g, acetophenone 10.8g, dimethylphenylcarbinol/L, 20.8g, α-methylstyrene 0.1
3. Or1-cumylphenol 0.29, paracumylphenol 0.6g, unknown substance 7.19, heavy substance 35.5
It was 9.

Example 4 The same catalyst as in Example 3 was placed in a stainless steel cylindrical column with a diameter of 23 mm and a length of 20 cm, containing 70 InIl (51 mm).

5q) After filling and fixing, the catalyst layer was heated and adjusted to 290°C.

The phenol distillation residue was supplied to this catalyst-packed column from the bottom at a rate of 7d/Hr using a heavy pump, and the supply pipe was
It was heated to around ℃. The reaction product that came out of the catalyst-packed column was cooled and analyzed by gas chromatography.

The composition of the phenol distillation residue, which is a raw material, is: acetophenone 20.8ffi1%, dimethylphenyl carbinol 6.8ffim%, phenol 19.8% heavy side, α-methylstyrene 10.6Iu% orthocumylphenol 3. The content was 81f%, paracumylphenol 13.7% by weight, unknown substance 1.0% by weight, and heavy substance 23.5% by weight.

The composition of the thermal decomposition reaction liquid obtained after 20 hours when the raw material was distributed through the fixed catalyst-packed column and the temperature distribution was stable was 9.4% of cumene and 14.3u of α-methylstyrene! %,
Acetophenone 18.6% strain, dimethylphenyl carbinol 0.1% heavy water, phenol 25.91ff1%
, α-methylstyrene 2] Rest 0. (4%, orthocumylphenol 0.9ff11%, paracumylphenol 2.3%, unknown substance 1.7%, heavy substance 26.2%)
% by weight.

From the above Examples and Comparative Examples, the production rate of cumene + α-medylsdyrene, the production rate of phenol, and the 10 loss rate of acetophenone were calculated and shown in Table 1.

The production rate (%) of α-methylstyrene is calculated by adding the number of moles of α-methylstyrene actually produced, the number of moles of dimethylphenylcarbinol contained in the raw material phenol distillation residue, and the number of moles of dimethylphenylcarbinol contained in the raw material phenol distillation residue. The value obtained by dividing the value obtained by doubling the number of moles of the polymer, the number of moles of orthocumylphenol, and the number of moles of paracumylphenol, and multiplying the resulting value by 100 is shown.

Similarly, the production rate of (α-methylstyrene + cumene)%
is the sum of the number of moles of α-methylstyrene actually produced and the number of moles of cumene, the number of moles of dimethylphenylcarbinol contained in the phenol distillation residue, which is the raw material, and the number of moles of α-methylstyrene. The value obtained by dividing the value obtained by doubling the number of moles of body, the number of moles of orthocumylphenol, and the number of moles of paracumylphenol, and then multiplying the iq value by 100 is shown.

The phenol production rate (%) was determined from the following formula.

(Number of moles of phenol in the product - original 1 = number of moles of phenol in l)/(number of moles of orthocumylphenol tens of moles of baramylphenol) x100 - The phenol production rate was determined from the following formula.

(Number of moles of phenol in the product)/(Number of moles of phenol in the raw material; Tens of moles of orthocumylphenol; Tens of moles of baramylphenol) X100 The acetophenone loss rate was determined from the following formula.

(Number of moles of acetophenone in the raw material - Number of moles of acetophenone in the product) / (Number of moles of acetonoenone in the raw material) It can be seen that not only cumene and α-methylstyrene can be recovered from the residual residue at a high recovery rate, but also phenol can be recovered at a high recovery rate, and it is also possible to suppress acetophenone from becoming heavy.

Claims (3)

[Claims] (1) Synthesize cumene hydroperoxide by oxidizing cumene with oxygen, and distilling and separating phenol and acetone from the reaction mixture obtained by acid decomposition. The ratio is 99:1 to 60
:40 and a specific surface area of 50m^2/g or more, a thermal decomposition reaction is carried out at a temperature of 200 to 310°C in the presence of an aluminum catalyst selected from the group consisting of silica-alumina catalysts, and the specific surface area is 50m^2/g or more. A method for recovering useful substances from phenol distillation residue, the method comprising recovering useful substances. (2) The method according to claim 1, wherein the thermal decomposition reaction is carried out at a temperature of 250 to 300°C. (3) The method according to claim 1, wherein the useful substances recovered are α-methylstyrene, phenol, cumene, and acetophenone.