Method for preparing phenolic product from coalified 2, 4 / 2, 5-methyl ethyl phenol mixture

Abstract

The invention belongs to the technical field of organic synthesis and separation, and particularly relates to a method for preparing phenolic products from a coalified 2, 4 / 2, 5-methyl ethyl phenol mixture. The invention provides a method for preparing a phenol product from a 2, 4 / 2, 5-methyl ethyl phenol mixture, which comprises the following steps: (1) carrying out cracking and transposition reaction on the 2, 4 / 2, 5-methyl ethyl phenol mixture, an acidic silicon-aluminum-chromium oxide solid catalyst and zirconium phosphate at 280-500 DEG C, cooling after the reaction is finished, and discharging ethylene generated in the reaction to obtain a 2, 4 / 2, 5-methyl ethyl phenol product; filtering to obtain a cracking reaction product; and (2) carrying out vacuum rectification treatment on the cracking reaction product. The method comprises the following steps: taking a 2, 4 / 2, 5-methyl ethyl phenol mixture as a raw material, removing ethyl in 2, 4 / 2, 5-methyl ethyl phenol at high temperature by using an acidic silicon-aluminum-chromium oxide solid catalyst to generate a cresol mixture, and rectifying to obtain a pure phenol product.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis and separation, and particularly relates to a method for preparing phenol products from a coal-based 2,4 / 2,5-methylethylphenol mixture. Background Art

[0002] Crude phenol is distilled into phenol, o-cresol, tri-cresol, m-p-cresol containing 55% meta-position, 99% m-p-cresol, and industrial xylenol. These are sold directly as products without undergoing fine separation. In fact, after the distillation of industrial xylenol, there is also a 2,4 / 2,5-methylethylphenol mixture with a boiling point of 222-223°C, which contains four isomers (2-ethyl-4-cresol, 2-ethyl-5-cresol, 2-methyl-4-ethylphenol, 2-methyl-5-ethylphenol), as well as a certain amount of impurities such as 3,5-xylenol, 2,4,6-trimethylphenol, 3,4-xylenol, and 2,3,6-trimethylphenol. Among them, due to the presence of 2-ethyl-4-methylphenol, 2-methyl-4-ethylphenol, 2,4,6-trimethylphenol, and 2,3,6-trimethylphenol, it is impossible to react with aldehyde to synthesize phenolic resin, so the 2,4 / 2,5-methylethylphenol mixture has few uses.

[0003] The crude phenol extracted from high-temperature coal tar has a relatively high content of 2,4 / 2,5-methylethylphenol, which cannot be separated by conventional distillation; the tert-butylation reaction can only produce a mixture of 2-ethyl-4-methylphenol and 2-methyl-4-ethylphenol, and a mixture of 2-ethyl-5-methylphenol and 2-methyl-5-ethylphenol. The utilization value is still very low and new methods need to be developed.

[0004] Therefore, it is necessary to develop new methods to achieve the effective utilization of 2,4 / 2,5-methylethylphenol mixture. Summary of the Invention

[0005] The present invention aims to at least partially address one of the technical problems in the related art. To this end, embodiments of the present invention provide a method for preparing a phenolic product from a 2,4 / 2,5-methylethylphenol mixture. This method addresses the problem of high 2,4 / 2,5-methylethylphenol content in xylenol extracted from phenol-containing coal tar, along with the presence of significant amounts of 2,4,6-trimethylphenol, 2,3,6-trimethylphenol, 3,5-xylenol, and 3,4-xylenol. This leads to difficulty in separating such xylenol, resulting in low yields of various pure xylenols and low product quality.

[0006] The method for preparing a phenolic product from a 2,4 / 2,5-methylethylphenol mixture according to an embodiment of the present invention comprises the following steps:

[0007] (1) subjecting a 2,4 / 2,5-methylethylphenol mixture, an acidic silica-aluminum-chromium oxide solid catalyst, and zirconium phosphate to a cracking and transposition reaction at 280-500° C., cooling the mixture after completion of the reaction, discharging ethylene produced in the reaction, and filtering the mixture to obtain a cracking reaction product; the 2,4 / 2,5-methylethylphenol mixture comprises 50-97 wt % of 2,4 / 2,5-methylethylphenol, 1-10 wt % of 2,4,6-trimethylphenol, 0-5 wt % of 2,3,6-trimethylphenol, 1-20 wt % of 3,5-xylenol, 1-20 wt % of 3,4-xylenol, and 0-10 wt % of others; the 2,4 / 2,5-methylethylphenol comprises 2-methyl-4-ethylphenol, 2-ethyl-4-methylphenol, 2-ethyl-5-methylphenol, and 2-methyl-5-ethylphenol;

[0008] (2) subjecting the cleavage reaction product obtained in step (1) to vacuum distillation.

[0009] The advantages and technical effects of the method for preparing phenol products from a 2,4 / 2,5-methylethylphenol mixture according to the embodiment of the present invention are as follows: 1. In the method according to the embodiment of the present invention, a deethylation reaction occurs in the presence of a high temperature and an acidic catalyst, and less methyl is lost. Ethylphenol is deethylated to generate cresol and ethylene, which are then distilled to obtain phenol products such as o-cresol and m-p-cresol; 2. In the method according to the embodiment of the present invention, the high-temperature oxidation performance of a concentrated sulfuric acid solution is utilized to remove sulfur-containing and ethylene-containing phenols from the 2,4 / 2,5-methylethylphenol mixture. Nitrogen substances make the nitrogen and sulfide contents in the prepared phenol products very low, and can be used for the synthesis of medicines and polymer materials; 3. The method of the embodiment of the present invention, under high-temperature catalytic conditions, o-cresol and p-cresol can be partially converted into m-cresol, 3,5-xylenol / 3,4-xylenol can be partially converted into 2,5-xylenol, and 2,4,6-trimethylphenol can be converted into 2,3,5-trimethylphenol. Distillation can also obtain 2,5-xylenol, 3,5-xylenol, 3,4-xylenol, and 2,3,5-trimethylphenol.

[0010] In some embodiments, in step (1), the mass ratio of the 2,4 / 2,5-methylethylphenol mixture, the acidic silica-aluminum-chromium oxide solid catalyst, and the zirconium phosphate is 100:10-30:0.05-3;

[0011] And / or, the silicon-aluminum-chromium oxide comprises silicon dioxide, acidic aluminum oxide and chromium oxide, and the mass ratio of silicon dioxide, acidic aluminum oxide and chromium oxide is 1:0.01-50:0.01-0.2.

[0012] In some embodiments, in step (1), the time of the cracking and transposition reaction is 3 to 10 hours, and the pressure of the cracking and transposition reaction is 1.5 to 6.7 MPa.

[0013] In some embodiments, in step (1), the cleavage reaction products include o-cresol, p-cresol, m-cresol, 3,5-dimethylphenol, 3,4-dimethylphenol, 2,5-dimethylphenol, and 2,3,5-trimethylphenol.

[0014] In some embodiments, in step (2), the vacuum degree of the vacuum distillation treatment is -0.085 to -0.095 MPa, and the reflux ratio is 10 to 25:1;

[0015] And / or, the vacuum distillation treatment obtains o-cresol, m-p-cresol, 2,5-xylenol, 3,5-xylenol, 3,4-xylenol, and 2,3,5-trimethylphenol.

[0016] In some embodiments, the process further comprises step (3): mixing coal-based mixed phenol and an acidic catalyst, introducing ethylene obtained in step (1) into the mixture for reaction, adding alkali solution to the system for neutralization after the reaction is completed, separating the salt layer, and subjecting the obtained material layer to vacuum distillation; the coal-based mixed phenol comprises 30-70 wt% of phenol and 70-30 wt% of o-cresol.

[0017] In some embodiments, the acidic catalyst comprises at least two of sulfuric acid, phosphoric acid, p-toluenesulfonic acid, benzenesulfonic acid, acidic resin, zirconium oxide, acidic aluminum oxide, or silicon oxide;

[0018] and / or, the coal-derived mixed phenol is 1 to 3 times the molar mass of 2,4 / 2,5-methylethylphenol in the coal-derived 2,4 / 2,5-methylethylphenol mixture;

[0019] And / or, the mass ratio of the coal-based mixed phenol to the acidic catalyst is 100:0.5-5.

[0020] In some embodiments, the reaction temperature is 220-250° C., the reaction pressure is 0.9-1.0 MPa, and the reaction time is 5-15 h.

[0021] and / or, the concentration of the alkali solution is 10-35%, and the alkali solution is added and neutralized to a pH of 7-8;

[0022] And / or, the pressure of the vacuum distillation treatment is -0.085 to -0.095 MPa, and the reflux ratio is 20 to 30:1;

[0023] And / or, the vacuum distillation treatment obtains phenol, o-cresol, o-ethylphenol, crude p-ethylphenol, 2-ethyl-6-methylphenol and 2-methyl-4-ethylphenol.

[0024] In some embodiments, the crude p-ethylphenol and methanol are added to a reactor, heated and stirred until the materials are dissolved, cooled first with circulating water and then with chilled brine, and then kept warm, filtered, drained, and dried to obtain p-ethylphenol.

[0025] In some embodiments, the mass of the methanol is 0.5 to 2 times the mass of the crude p-ethylphenol;

[0026] And / or, the temperature of the heating and stirring is 60-70°C;

[0027] and / or, using the circulating water to reduce the temperature to 30-40° C. in 2-3 hours, and using the chilled brine to reduce the temperature to 0-10° C. in 2-4 hours;

[0028] And / or, the insulation time is 1 to 3 hours. DETAILED DESCRIPTION

[0029] The following describes in detail embodiments of the present invention. The embodiments are exemplary and intended to explain the present invention, but are not to be construed as limiting the present invention.

[0030] The method for preparing a phenolic product from a 2,4 / 2,5-methylethylphenol mixture according to an embodiment of the present invention comprises the following steps:

[0031] (1) subjecting a 2,4 / 2,5-methylethylphenol mixture, an acidic silica-aluminum-chromium oxide solid catalyst, and zirconium phosphate to a cracking and transposition reaction at 280-500° C., cooling the mixture after completion of the reaction, discharging ethylene produced in the reaction, and filtering the mixture to obtain a cracking reaction product; the 2,4 / 2,5-methylethylphenol mixture comprises 50-97 wt % of 2,4 / 2,5-methylethylphenol, 1-10 wt % of 2,4,6-trimethylphenol, 0-5 wt % of 2,3,6-trimethylphenol, 1-20 wt % of 3,5-xylenol, 1-20 wt % of 3,4-xylenol, and 0-10 wt % of other substances; the 2,4 / 2,5-methylethylphenol comprises 2-methyl-4-ethylphenol, 2-ethyl-4-methylphenol, 2-ethyl-5-methylphenol, and 2-methyl-5-ethylphenol;

[0032] (2) subjecting the cleavage reaction product obtained in step (1) to vacuum distillation.

[0033] In the method of preparing a phenolic product from a 2,4 / 2,5-methylethylphenol mixture according to an embodiment of the present invention, a deethylation reaction occurs under high temperature and in the presence of an acidic catalyst, with less methyl loss. The ethylphenol is deethylated to produce cresol and ethylene, which are then subjected to rectification to obtain phenolic products such as o-cresol and m- / p-cresol. The method of the embodiment of the present invention utilizes the high-temperature oxidation performance of a concentrated sulfuric acid solution to remove sulfur-containing and nitrogen-containing substances from the 2,4 / 2,5-methylethylphenol, so that the obtained phenolic product has very low nitrogen and sulfide contents and can be used for the synthesis of medicines and polymer materials. In the method of the embodiment of the present invention, under high-temperature catalytic conditions, o-cresol and p-cresol can be partially converted into m-cresol, 3,5-xylenol / 3,4-xylenol can be partially converted into 2,5-xylenol, and 2,4,6-trimethylphenol can be converted into 2,3,5-trimethylphenol. Distillation can also obtain 2,5-xylenol, 3,5-xylenol, 3,4-xylenol, and 2,3,5-trimethylphenol.

[0034] Since alkyl groups will undergo deethylation and other alkyl reactions under high temperature and catalyst (especially acidic catalyst), the temperature required for demethylation is high. By controlling the temperature, less methyl groups can be lost, and mainly ethyl groups and long-chain alkyl groups will be lost. Methyl ethylphenol is deethylated to produce cresol and ethylene, which can be further distilled to obtain products such as o-cresol and m-p-cresol. Since the dealkylation is carried out under acidic conditions and at high temperature, most of the pyridine base and sulfide entrained in the phenolic material are removed, so the nitrogen and sulfide content of the obtained o-cresol, m-p-cresol and other products is very low, thereby improving the quality of the phenolic products.

[0035] In some embodiments, preferably, the 2,4 / 2,5-methylethylphenol mixture includes 60-80 wt% of 2,4 / 2,5-methylethylphenol, 3-8 wt% of 2,4,6-trimethylphenol, 1-3 wt% of 2,3,6-trimethylphenol, 5-15 wt% of 3,5-xylenol, 5-15 wt% of 3,4-xylenol, and 3-8 wt% of others (including m-p-ethylphenol, with m-p-ethylphenol required to be ≤1%).

[0036] In some embodiments, preferably, in step (1), the mass ratio of the 2,4 / 2,5-methylethylphenol mixture, the acidic silica-aluminum-chromium oxide solid catalyst and the zirconium phosphate is 100:10-30:0.05-3.

[0037] In some embodiments, the silicon-aluminum-chromium oxide preferably comprises silicon dioxide, acidic alumina, and chromium oxide, wherein the mass ratio of silicon dioxide, acidic alumina, and chromium oxide is 1:0.01-50:0.01-0.2. Further preferably, the mass ratio of silicon dioxide to acidic alumina is 1:0.05-20.

[0038] In some embodiments, preferably, in step (1), the time of the cracking and transposition reaction is 3 to 10 hours, and the pressure of the cracking and transposition reaction is 2.4 to 6.7 MPa.

[0039] In some embodiments, preferably, in step (1), the cleavage reaction products include o-cresol, p-cresol, m-cresol, 3,5-dimethylphenol, 3,4-dimethylphenol, 2,5-dimethylphenol, and 2,3,5-trimethylphenol.

[0040] In some embodiments, preferably, in step (1), the cracking and transposition reaction is carried out in a stainless steel high-pressure reactor with an external stainless steel condenser and an inner coil; after the cracking and transposition reaction is completed, the temperature is cooled using the heat transfer oil in the inner coil, and the temperature is quickly cooled to 280°C within 0.5 to 1 hour, and then the temperature is reduced to ≤170°C within 0.5 to 1 hour.

[0041] In some embodiments, preferably, the ethylene produced during the cracking and metathesis reaction is pressurized to 5 MPa by a pressure pump and stored in a stainless steel spherical tank; after the gas is exhausted, the cracking and metathesis reaction condensate is slightly cooled and replaced with nitrogen for 0.5 hours, and then filtered, and the solid catalyst is reused.

[0042] In some embodiments, preferably, in step (2), the vacuum degree of the vacuum distillation treatment is -0.085 to -0.095 MPa, and the reflux ratio is 10 to 25:1;

[0043] And / or, the vacuum distillation treatment obtains o-cresol, m-p-cresol, 2,5-xylenol, 3,5-xylenol, 3,4-xylenol, and 2,3,5-trimethylphenol.

[0044] Due to the high-temperature oxidation performance of concentrated sulfuric acid solution, sulfur- and nitrogen-containing substances in 2,4 / 2,5-methylethylphenol are removed, so that the nitrogen and sulfide contents in the obtained phenol products are very low. Therefore, the nitrogen and sulfide contents in o-cresol obtained by vacuum distillation are ≤2ppm, and the nitrogen and sulfide contents in m-p-cresol are ≤1ppm, resulting in high-grade products.

[0045] In some embodiments, preferably, the process further includes step (3): mixing coal-based mixed phenol and an acidic catalyst, introducing the ethylene obtained in step (1) into the mixture for reaction, adding alkali solution to the system for neutralization after the reaction is completed, separating the salt layer, and adding the obtained material layer to the bottom of a distillation tower for vacuum distillation treatment; the coal-based mixed phenol comprises 30-70 wt% of phenol and 70-30 wt% of o-cresol.

[0046] In some embodiments, preferably, the acidic catalyst includes at least two of sulfuric acid, phosphoric acid, p-toluenesulfonic acid, benzenesulfonic acid, acidic resin, zirconium oxide, acidic aluminum oxide or silicon oxide; further preferably, the acidic catalyst includes sulfuric acid and phosphoric acid, wherein the mass ratio of sulfuric acid to phosphoric acid is 9-7:1-3.

[0047] In some embodiments, preferably, the coal-based mixed phenol is 1 to 3 times the molar mass of 2,4 / 2,5-methylethylphenol in the coal-based 2,4 / 2,5-methylethylphenol mixture;

[0048] And / or, the mass ratio of the coal-based mixed phenol to the acidic catalyst is 100:0.5-5.

[0049] In some embodiments, preferably, the reaction temperature is 220-250° C., the reaction pressure is 0.9-1.0 MPa, and the reaction time is 5-15 h;

[0050] and / or, the concentration of the alkali solution is 10-35%, and the alkali solution is added and neutralized to a pH of 7-8;

[0051] And / or, the pressure of the vacuum distillation treatment is -0.085 to -0.095 MPa, and the reflux ratio is 20 to 30:1;

[0052] And / or, the vacuum distillation treatment obtains phenol, o-cresol, o-ethylphenol, crude p-ethylphenol, 2-ethyl-6-methylphenol and 2-methyl-4-ethylphenol.

[0053] In the embodiment of the present invention, the nitrogen compounds and sulfides in the obtained phenol are both ≤5 ppm, the nitrogen compounds and sulfides in the obtained o-cresol are both ≤2 ppm, and the nitrogen compounds and sulfides in the obtained o-ethylphenol are both ≤2 ppm.

[0054] In some embodiments, preferably, the alkali solution comprises at least one of sodium hydroxide solution, potassium hydroxide solution, sodium carbonate solution, potassium carbonate solution, sodium bicarbonate solution or potassium bicarbonate solution. Further preferably, the alkali solution is an aqueous sodium hydroxide solution.

[0055] In some embodiments, preferably, the crude p-ethylphenol and methanol are added to a reactor, the temperature is raised and stirred until the materials are dissolved, the temperature is first cooled with circulating water and then with chilled brine, and then the p-ethylphenol is obtained by heat preservation, filtration, drying, and drying.

[0056] In some embodiments, preferably, the mass of the methanol is 0.5 to 2 times the mass of the crude p-ethylphenol;

[0057] And / or, the temperature of the heating and stirring is 60-70°C;

[0058] and / or, using the circulating water to reduce the temperature to 30-40° C. in 2-3 hours, and using the chilled brine to reduce the temperature to 0-10° C. in 2-4 hours;

[0059] And / or, the insulation time is 1 to 3 hours.

[0060] The technical solution of the present invention is described in detail below in conjunction with specific embodiments.

[0061] Example 1

[0062] (1) Cleavage and translocation reaction

[0063] A stainless steel high-pressure reactor with an external stainless steel condenser and an inner coil was charged with 750 parts of an acidic silica-alumina-chromium oxide solid catalyst (all parts are by weight in the examples) (the mass ratio of silicon dioxide, acidic alumina and chromium oxide is 1:2:0.2), 40 parts of zirconium phosphate, and 5000 parts of a 2,4 / 2,5-methylethylphenol mixture (containing 341 parts of 3,5-xylenol, 93 parts of 2,4,6-trimethylphenol, 1302 parts of 2-ethyl-4-methylphenol, 1003 parts of 2-ethyl-5-methylphenol, 838 parts of 2-methyl-4-ethylphenol, 699 parts of 2-methyl-5-ethylphenol, 528 parts of 3,4-xylenol, 52 parts of 2,3,6-trimethylphenol, and 144 parts of others). The reactor was sealed and heated to 350° C. for 6 hours, and the pressure was gradually increased to a stable level of 2.5 The reaction was terminated by cooling the inner coil with programmed cooling heat-conducting oil (the temperature of the heat-conducting oil was gradually and slowly reduced from high temperature to 80°C), first cooled to 280°C in 0.7 hours, and then the material temperature was reduced to 170°C in 1 hour, and the ethylene released in the reaction was gradually discharged; the discharged gas was pressurized to 5MPa by a pressure pump and stored in a stainless steel spherical tank; after the gas was discharged, the cracking reaction condensate was slightly cooled and replaced with nitrogen for 0.5 hours, and 4133.6 parts of cracking reaction products were obtained by filtration (containing 332.3 parts of o-cresol, 543.6 parts of p-cresol, 2144.5 parts of m-cresol, 230 parts of 2,5-xylenol, 415.3 parts of 3,5-xylenol, 215 parts of 3,4-xylenol, 116.3 parts of 2,3,5-trimethylphenol and 136.6 parts of others), and the solid catalyst was applied mechanically.

[0064] (2) Synthesis of o-ethylphenol, p-ethylphenol, 2-ethyl-6-methylphenol, and 2-methyl-4-ethylphenol

[0065] While the cracking and transposition reactions are in step (1), 3750 parts of coal-based mixed phenols (2550 parts of phenol, 1200 parts of o-cresol, 186 ppm of nitride, 122 ppm of sulfide) and 37.5 parts of sulfuric acid / phosphoric acid (the coal-based mixed phenol is 1.35 times the molar mass of 2,4 / 2,5-methylethylphenol in the raw material 2,4 / 2,5-methylethylphenol mixture, and the mass ratio of 98% sulfuric acid to 85% phosphoric acid is 9:1) are added to a stainless steel autoclave, stirring is started, the temperature is raised to 230° C., the pressurized ethylene collected in the ethylene spherical tank in step (1) is slowly decompressed and introduced into the stainless steel autoclave for reaction, the autoclave temperature is maintained at 230-240° C., the pressure is 0.9-1.0 MPa, the olefin feeding time is 5 hours, and ventilation is stopped when the pressure on the spherical tank drops to 1.1 MPa. The autoclave is kept warm for reaction for 3 hours. When the autoclave pressure drops to 0.6 MPa or the autoclave pressure does not drop, the reaction is continued. The reaction was stopped when the pH was low; 210 parts of a 30% aqueous sodium hydroxide solution was added to the material in the kettle to neutralize it to pH 7.5, the salt layer was separated, and the material layer was added to the kettle of a distillation tower (theoretical plate number 300), at -0.09 MPa, a reflux ratio of 25 to 30, and distillation was performed to obtain 832.2 parts of 99.9% phenol (0.9 ppm nitrogen compound, 0.7 ppm sulfide compound), 715.7 parts of 99.7% o-cresol (0.9 ppm nitrogen compound, 0.9 ppm sulfide compound), and 100 parts of 100 parts of 99.7% o-cresol (0.9 ppm nitrogen compound, 0.9 ppm sulfide compound). ppm, sulfide 0.6ppm), 873.0 parts of 99.3% o-ethylphenol (0.7ppm nitrogen, 0.5ppm sulfide), 290.6 parts of 99.1% 2-ethyl-6-methylphenol, 1250 parts of 96.62% crude p-ethylphenol (1207.8 parts of p-ethylphenol, 26.0 parts of m-ethylphenol, 16.2 parts of others), and 280.1 parts of 99.2% 2-methyl-4-ethylphenol.

[0066] 968.2 parts of 96.62% crude p-ethylphenol and 900 parts of methanol were added to a reactor, stirred, and heated to 65°C to completely dissolve the materials. The mixture was then cooled to 33°C in a cold water bath for 2 hours, then cooled to 0°C in an ice water bath for 2.5 hours, kept warm for 1 hour, filtered, drained, and dried to obtain 890.1 parts of 99.75% p-ethylphenol, with a refined yield of 94.9%.

[0067] (3) Distillation separation of cracking products

[0068] 4133.6 parts of the cleavage reaction product obtained in step (1) (containing 332.3 parts of o-cresol, 543.6 parts of p-cresol, 2144.5 parts of m-cresol, 230 parts of 2,5-dimethylphenol, 415.3 parts of 3,5-dimethylphenol, 215 parts of 3,4-dimethylphenol, 116.3 parts of 2,3,5-trimethylphenol, and 136.6 parts of others) were added to the bottom of a distillation tower (100 parts of dimethyl diphenyl ether high boiling point solvent had been added to the bottom of the tower, and the tower had 300 theoretical plates), and subjected to vacuum distillation (vacuum degree -0.088 MPa, reflux ratio 20-25) : 1), 263.6 parts of 99.6% o-cresol (0.7 ppm nitrogen compound, 0.7 ppm sulfide), 2453.5 parts of 99.69% m-p-cresol (490.8 parts of p-cresol, 1955.3 parts of m-cresol, and other 7.4 parts of 0.8 ppm nitrogen compound and 0.6 ppm sulfide compound), 180.7 parts of 99.3% 2,5-xylenol, 298.3 parts of 99.1% 3,5-xylenol, 169.6 parts of 99.5% 3,4-xylenol, and 97.5 parts of 99.2% 2,3,5-trimethylphenol were obtained.

[0069] Example 2

[0070] (1) Cleavage and translocation reaction

[0071] A stainless steel high-pressure reactor with an external stainless steel condenser and an inner coil was charged with 1000 parts of an acidic silica-alumina-chromium oxide solid catalyst (the mass ratio of silica, acidic alumina and chromium oxide was 2:2:0.15) and 75 parts of zirconium phosphate. 5000 parts of a 2,4 / 2,5-methylethylphenol mixture (including 341 parts of 3,5-xylenol, 93 parts of 2,4,6-trimethylphenol, 1302 parts of 2-ethyl-4-methylphenol, 1003 parts of 2-ethyl-5-methylphenol, 838 parts of 2-methyl-4-ethylphenol, 699 parts of 2-methyl-5-ethylphenol, 528 parts of 3,4-xylenol, 52 parts of 2,3,6-trimethylphenol and 144 parts of others) was added. The reactor was sealed and heated to 300°C for 8 hours. The pressure was gradually increased to a stable level of 1.8-1.9 MPa. a. End the reaction, cool the inner coil with programmed cooling heat-conducting oil (the temperature of the heat-conducting oil is gradually and slowly reduced from a high temperature to 80°C), first cool to 280°C in 0.2 hours, and then reduce the material temperature to 170°C in 50 minutes, and gradually discharge the ethylene released in the reaction; the excluded gas is pressurized to 5MPa by a pressure pump and stored in a stainless steel spherical tank; after the gas is discharged, the cracking reaction condensate is slightly cooled and replaced with nitrogen for 0.5 hour, and 4108.2 parts of cracking reaction products (containing 417.5 parts of o-cresol, 635.9 parts of p-cresol, 1949 parts of m-cresol, 196.4 parts of 2,5-xylenol, 393.2 parts of 3,5-xylenol, 270.7 parts of 3,4-xylenol, 105.1 parts of 2,3,5-trimethylphenol, and 140.4 parts of others) are obtained by filtration, and the solid catalyst is applied mechanically.

[0072] (2) Synthesis of o-ethylphenol, p-ethylphenol, 2-ethyl-6-methylphenol, and 2-methyl-4-ethylphenol

[0073] At the same time as the cracking and transposition reactions in step (1), 5000 parts of o-cresol fraction (1720 parts of phenol, 3280 parts of o-cresol, 113 ppm of nitride, 105 ppm of sulfide) and 37.5 parts of sulfuric acid / phosphoric acid (the mixed phenol is 1.72 times the molar mass of 2,4 / 2,5-methylethylphenol in the raw material 2,4 / 2,5-methylethylphenol mixture, and the mass ratio of 98% sulfuric acid to 85% phosphoric acid is 8:2) are added to a stainless steel autoclave, stirring is started, the temperature is raised to 230° C., the pressurized ethylene collected in the ethylene spherical tank in step (1) is slowly decompressed and introduced into the stainless steel autoclave for reaction, the autoclave temperature is maintained at 230-240° C., the pressure is 0.9-1.0 MPa, the olefin feeding time is 5 hours, and ventilation is stopped when the pressure on the spherical tank drops to 1.1 MPa. The autoclave is kept warm for reaction for 3 hours. When the autoclave pressure drops to 0.6 MPa or the autoclave pressure does not drop, the pressurized ethylene is slowly decompressed and introduced into the stainless steel autoclave for reaction. Stop the reaction; add 224 parts of 30% sodium hydroxide aqueous solution to the material in the kettle to neutralize it to pH 7.5, separate the salt layer, and add the material layer to the kettle of the distillation tower (theoretical plate number 300). At -0.09 MPa and a reflux ratio of 25 to 30:1, distillation is carried out to obtain 479 parts of 99.8% phenol (0.7 ppm nitrogen compound, 0.8 ppm sulfide compound), 2226.8 parts of 99.8% o-cresol (0.6 ppm nitrogen compound, 0.6 ppm sulfide compound), and 1,200 parts of 99.8% o-cresol (0.6 ppm nitrogen compound, 0.6 ppm sulfide compound). ppm, sulfide 0.6ppm), 661.6 parts of 99.2% o-ethylphenol (0.7ppm nitrogen, 0.8ppm sulfide), 330.1 parts of 99.1% 2-ethyl-6-methylphenol, 874.1 parts of 96.84% crude p-ethylphenol (846.6 parts of p-ethylphenol, 16.1 parts of m-ethylphenol, 11.4 parts of others), and 894.1 parts of 99.3% 2-methyl-4-ethylphenol.

[0074] 874.1 parts of 96.84% crude p-ethylphenol and 900 parts of methanol were added to a reactor, stirred, and heated to 65°C to completely dissolve the materials. The mixture was then cooled to 38°C in a cold water bath for 1.5 hours, then cooled to 0°C in an ice water bath for 3 hours, kept warm for 2 hours, filtered, drained, and dried to obtain 787.1 parts of 99.8% p-ethylphenol with a refined yield of 92.8%.

[0075] (3) Distillation separation of cracking products

[0076] 4108.2 parts of the cleavage reaction product obtained in step (1) (containing 417.5 parts of o-cresol, 635.9 parts of p-cresol, 1949 parts of m-cresol, 196.4 parts of 2,5-dimethylphenol, 393.2 parts of 3,5-dimethylphenol, 270.7 parts of 3,4-dimethylphenol, 105.1 parts of 2,3,5-trimethylphenol, and 140.4 parts of others) were added to the bottom of a distillation tower (100 parts of dimethyl diphenyl ether high boiling point solvent had been added to the bottom of the tower, and the tower had 300 theoretical plates), and vacuum distillation (vacuum degree -0.09 MPa, reflux ratio 20-25:1) was performed to obtain 99.9% phenol 63.9 parts (nitride 0.9ppm, sulfide 0.8ppm), 317.5 parts of 99.8% o-cresol (nitride 0.8ppm, sulfide 0.5ppm), 2331.2 parts of 99.69% m-p-cresol (568.4 parts of p-cresol, 1759.2 parts of m-cresol, and 3.6 parts of other nitrogen compounds 0.9ppm and sulfide 0.8ppm), 154.1 parts of 99.4% 2,5-dimethylphenol, 281.8 parts of 99.3% 3,5-dimethylphenol, 213.3 parts of 99.6% 3,4-dimethylphenol, and 87.1 parts of 99.5% 2,3,5-trimethylphenol.

[0077] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0078] Although the above embodiments have been shown and described, it is understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. Changes, modifications, substitutions and variations of the above embodiments by those skilled in the art are all within the scope of protection of the present invention.

Claims

1. A method for preparing a phenolic product from a 2,4 / 2,5-methylethylphenol mixture, characterized in that: The following steps are involved: (1) subjecting a 2,4 / 2,5-methylethylphenol mixture, an acidic silica-aluminum-chromium oxide solid catalyst, and zirconium phosphate to a cracking and metathesis reaction at 280-500° C., cooling the mixture after completion of the reaction, discharging ethylene produced in the reaction, and filtering the mixture to obtain a cracking reaction product; the 2,4 / 2,5-methylethylphenol mixture comprises 50-97 wt % of 2,4 / 2,5-methylethylphenol, 1-10 wt % of 2,4,6-trimethylphenol, 0-5 wt % of 2,3,6-trimethylphenol, 1-20 wt % of 3,5-xylenol, 1-20 wt % of 3,4-xylenol, and 0-10 wt % of others; the 2,4 / 2,5-methylethylphenol comprises 2-methyl-4-ethylphenol, 2-ethyl-4-methylphenol, 2-ethyl-5-methylphenol, and 2-methyl-5-ethylphenol; (2) subjecting the cleavage reaction product obtained in step (1) to vacuum distillation.

2. The method for preparing phenolic products from coal-based 2,4 / 2,5-methylethylphenol mixture according to claim 1, characterized in that: In the step (1), the mass ratio of the 2,4 / 2,5-methylethylphenol mixture, the acidic silica-aluminum-chromium oxide solid catalyst and the zirconium phosphate is 100:10-30:0.05-3; And / or, the silicon-aluminum-chromium oxide comprises silicon dioxide, acidic aluminum oxide and chromium oxide, and the mass ratio of silicon dioxide, acidic aluminum oxide and chromium oxide is 1:0.01-50:0.01-0.

2.

3. The method for preparing phenolic products from coal-based 2,4 / 2,5-methylethylphenol mixture according to claim 1, characterized in that: In the step (1), the time for the cracking and transposition reaction is 3 to 10 hours, and the pressure of the cracking and transposition reaction is 1.5 to 6.7 MPa.

4. The method for preparing phenolic products from coal-based 2,4 / 2,5-methylethylphenol mixture according to claim 1, characterized in that: In the step (1), the cleavage reaction products include o-cresol, p-cresol, m-cresol, 3,5-dimethylphenol, 3,4-dimethylphenol, 2,5-dimethylphenol, and 2,3,5-trimethylphenol.

5. The method for preparing phenolic products from coal-based 2,4 / 2,5-methylethylphenol mixture according to claim 1, characterized in that: In the step (2), the vacuum degree of the vacuum distillation treatment is -0.085 to -0.095 MPa, and the reflux ratio is 10 to 25:1; And / or, the vacuum distillation treatment obtains o-cresol, m-p-cresol, 2,5-xylenol, 3,5-xylenol, 3,4-xylenol, and 2,3,5-trimethylphenol.

6. The method for preparing phenolic products from coal-based 2,4 / 2,5-methylethylphenol mixture according to claim 1, characterized in that: The method further comprises the step (3): mixing coal-based mixed phenol and an acidic catalyst, introducing the ethylene obtained in the step (1) into the mixture for reaction, adding alkali solution to the system for neutralization after the reaction is completed, separating the salt layer, and subjecting the obtained material layer to vacuum distillation; the coal-based mixed phenol comprises 30-70 wt% of phenol and 70-30 wt% of o-cresol.

7. The method for preparing phenolic products from coal-based 2,4 / 2,5-methylethylphenol mixture according to claim 6, characterized in that: The acidic catalyst comprises at least two of sulfuric acid, phosphoric acid, p-toluenesulfonic acid, benzenesulfonic acid, acidic resin, zirconium oxide, acidic aluminum oxide or silicon oxide; and / or, the coal-derived mixed phenol is 1 to 3 times the molar mass of 2,4 / 2,5-methylethylphenol in the coal-derived 2,4 / 2,5-methylethylphenol mixture; And / or, the mass ratio of the coal-based mixed phenol to the acidic catalyst is 100:0.5-5.

8. The method for preparing phenolic products from coal-based 2,4 / 2,5-methylethylphenol mixture according to claim 6, characterized in that: The reaction temperature is 220-250° C., the reaction pressure is 0.9-1.0 MPa, and the reaction time is 5-15 h. and / or, the concentration of the alkali solution is 10-35%, and the alkali solution is added and neutralized to a pH of 7-8; And / or, the pressure of the vacuum distillation treatment is -0.085 to -0.095 MPa, and the reflux ratio is 20 to 30:1; And / or, the vacuum distillation treatment obtains phenol, o-cresol, o-ethylphenol, crude p-ethylphenol, 2-ethyl-6-methylphenol and 2-methyl-4-ethylphenol.

9. The method for preparing phenolic products from coal-based 2,4 / 2,5-methylethylphenol mixture according to claim 8, characterized in that: The crude p-ethylphenol and methanol are added to the reactor, heated and stirred until the materials are dissolved, cooled by circulating water and then by chilled brine, and then kept warm, filtered, drained and dried to obtain p-ethylphenol.

10. The method for preparing phenolic products from coal-based 2,4 / 2,5-methylethylphenol mixture according to claim 9, characterized in that: The mass of the methanol is 0.5 to 2 times the mass of the crude p-ethylphenol; And / or, the temperature of the heating and stirring is 60-70°C; and / or, using the circulating water to reduce the temperature to 30-40° C. in 2-3 hours, and using the chilled brine to reduce the temperature to 0-10° C. in 2-4 hours; And / or, the insulation time is 1 to 3 hours.