CN104946303A - Method for selectively separating phenol mixture from oil - Google Patents

Abstract

The invention relates to a method for selectively separating a phenol mixture from oil, which comprises the following steps: by using a quaternary ammonium salt as a separating agent, selectively forming a congruent melting liquid from the separating agent and phenol compounds (phenol, cresol and dimethyl phenol) in the oil at 0-30 DEG C, thereby separating the phenol compounds from the oil; and carrying out back extraction on the phenol compounds containing the congruent melting liquid to separate the phenol substances from the quaternary ammonium salt, thereby obtaining the product and recovering the extractant. The method has the advantages of simple technique, low separate cost and environment friendliness.

Description

A method for selectively separating phenolic mixtures in oil

technical field

The invention relates to a method for selectively separating phenolic compounds from aromatic and aliphatic hydrocarbon mixtures.

Background technique

Phenolic compounds are an important class of chemical raw materials, widely used in fiber, plastics, pesticides, medicine, preservatives, explosives synthesis and other fields. Coal pyrolysis oil, coal hydrogenation liquefaction oil and biomass pyrolysis oil contain a large amount of phenolic compounds, such as phenol, cresol, xylenol and other substances. The traditional method of separating phenolic compounds from these oils is at first to adopt lye chemical extraction method, the principle of lye (such as sodium hydroxide solution) extraction method is to utilize phenolic compounds to have weak acidity, after reacting with sodium hydroxide, A water-soluble sodium phenate solution is formed, and the phenolic compounds are transferred from the oil phase to the water phase to achieve the purpose of separation. The regeneration process of sodium phenate is: reducing phenolic compounds with carbonic acid and sulfuric acid, which are more acidic than phenol, to obtain a phenolic mixture (crude phenol); secondly, the phenolic mixture is separated by rectification. Although this separation method has high selectivity, it needs to consume a large amount of acid-base solution and has high requirements for equipment; after pickling, a large amount of phenol-containing wastewater is produced, resulting in complicated post-treatment process and serious environmental pollution; due to the phenolic mixture The boiling point is close, resulting in high energy consumption for separation. In addition to the above separation methods, methods currently being studied include superheated water extraction, brine extraction, and alcohol-water extraction separation. Although these can separate phenolic compounds from oil to a certain extent, they still require a large amount of Organic solvents or water also have serious pollution and low separation efficiency. The use of water will produce a large amount of phenol-containing wastewater, and the use of organic solvents cannot avoid the solvent loss caused by the dissolution of organic solvents in oil, resulting in higher separation costs.

As mentioned above, the phenolic mixture obtained from coal pyrolysis oil, coal hydrogenation liquefied oil and biomass pyrolysis oil is mainly composed of phenol, cresol, xylenol and other substances, which cannot be obtained in the above extraction and separation process. Selective separation of these species necessitates subsequent re-separation.

Contents of the invention

The purpose of the present invention is to provide a method for selectively separating phenolic mixtures (phenol, cresol, xylenol) in oil with simple process, low separation cost and environmental friendliness using quaternary ammonium salt as an extraction agent.

The present invention uses quaternary ammonium salt as a separating agent to selectively form eutectic liquid with phenolic compounds (phenol, cresol, xylenol) in oil at a temperature range of 0°C-30°C, thereby realizing the separation of phenolic compounds in oil Separation, the phenolic compound containing the eutectic liquid is separated from the quaternary ammonium salt by back extraction, the product is obtained, and the extraction agent is recovered.

The invention provides a method for selectively separating phenolic mixtures in oil, comprising the steps of:

(1) According to the amount of quaternary ammonium salt added is 0.3 times -0.6 times the number of moles of phenol, add quaternary ammonium salt to the oil, at the separation temperature of 0°C-30°C, after stirring for 1min-30min, let it stand for 1min -20min, the system is divided into two phases, the quaternary ammonium salt selectively forms a eutectic solvent with the phenol with strong force first, and the eutectic solvent is immiscible with the oil phase, so it is separated from the oil phase, and after separation, a phenol-rich Eutectic solvents and dephenolized oils;

(2) Add quaternary ammonium salt to 0.4-0.7 times the number of moles of cresol, add quaternary ammonium salt to the dephenolized oil in step (1), and stir for 1 min at the separation temperature of 0°C-30°C After -30min, let it stand for 1min-20min, the quaternary ammonium salt selectively forms a eutectic solvent with cresol, which is the second most active, and the eutectic solvent is immiscible with the oil phase and is separated from the oil phase. Eutectic solvents of phenols and oils dephenolized and cresolized;

(3) The amount of the quaternary ammonium salt added is 0.5-0.9 times the molar number of xylenol, then add the quaternary ammonium salt to the dephenolized oil in step (2), and stir at a separation temperature of 0°C-30°C After 1min-30min, stand still for 1min-20min, the quaternary ammonium salt selectively forms a eutectic solvent with xylenol, which has a smaller force, and the eutectic solvent is immiscible with the oil phase and is separated from the oil phase. After separation, Eutectic solvents rich in xylenol and neutral oils dephenolized, cresol and xylenol;

(4) After the above separation is completed, carry out vacuum distillation on the three eutectic solvents at a pressure of 0.01atm-0.06atm and a temperature of 60°C-90°C to remove the neutral oil carried therein;

(5) According to the volume ratio of anti-solvent and eutectic solvent as 4-7:1, add anti-solvent to the above three eutectic solvents for removing neutral oil respectively, at the separation temperature of 0°C-30°C, quaternary ammonium Salt recrystallization is precipitated in solid form, filtered to realize the regeneration of quaternary ammonium salt, and three kinds of antisolvent solutions containing phenol are obtained;

(6) Distill the three anti-solvent solutions containing phenol respectively, separate the phenolic compound and the anti-solvent, obtain phenol, cresol, xylenol and anti-solvent respectively, and reuse the anti-solvent.

In the above method, the oil is a mixture of aromatic hydrocarbons, aliphatic hydrocarbons and phenolic compounds, wherein the aromatic hydrocarbons and aliphatic hydrocarbons are neutral oils.

In the above method, the concentration of phenolic compounds in the oil is 50g/L-300g/L.

In the above method, the quaternary ammonium salt is choline chloride, tetramethylammonium chloride, tetraethylammonium chloride, methyltriethylammonium chloride, tetraethylammonium bromide or tetramethylammonium bromide Ammonium. The quaternary ammonium salt added in steps (1)-(3) is the same.

In the above method, the antisolvent is diethyl ether, isopropyl ether, n-butyl ether, ethyl acetate or methyl formate.

The principle of selective extraction and separation of phenolic compounds in oil by quaternary ammonium salts is that phenolic compounds in oil contain functional groups such as hydroxyl groups, which can form intermolecular hydrogen bonds with halide ions of quaternary ammonium salts, thereby reducing the concentration of quaternary ammonium salts. Intramolecular forces with phenolic compounds, and then form a eutectic solvent. This eutectic solvent is immiscible with the oil phase and forms a new phase, which enables the separation of oil phenols. Due to the different structures of phenol, cresol and xylenol, they have different forces when they form eutectic solvents with quaternary ammonium salts. The force is different. Among the three phenols, phenol has the strongest effect, forming a eutectic solvent with quaternary ammonium salts first, followed by cresol, and finally xylenol. If the addition of quaternary ammonium salts is not excessive, there will be competition between different phenols and quaternary ammonium salts, and the one with the largest force will form a eutectic solvent first, so that the separation of different phenols can be achieved by gradually adding quaternary ammonium salts. If too much quaternary ammonium salt is added at one time, all phenols will react with quaternary ammonium salt at the same time to form a eutectic solvent, which can only separate neutral oil and phenolic compounds.

Compared with the prior art, the present invention at least has the following beneficial effects.

1. Compared with the traditional sodium hydroxide solution elution method, the present invention adopts quaternary ammonium salt as the separating agent, which can be reused, and can also avoid the use of a large amount of acid-base solution and the generation of phenol-containing wastewater, reducing the separation cost.

2. Compared with the traditional sodium hydroxide solution elution method, the present invention adopts the stepwise extraction method to extract the phenolic mixture in the oil, the extractant has selectivity, realizes the separation of three kinds of phenols at the same time, and the separation efficiency is high.

3. No water is used in the separation process of the present invention, and no phenol-containing wastewater is produced, which reduces environmental pollution;

4. The present invention can separate phenolic substances with similar properties from the mixture of oil and phenol, realize extraction and separation at the same time, and have high separation efficiency;

5. Compared with the traditional extraction method, the extraction agent quaternary ammonium salt of the present invention consumes less amount, can be reused, and greatly reduces the volume of the separator.

6. The anti-solvent of the present invention can also be used repeatedly, greatly reducing the separation cost.

Detailed ways

The process of selectively separating phenolic compounds in oil using quaternary ammonium salt as a separating agent provided by the present invention will be further described in detail below in conjunction with examples, but the present invention is not limited thereto.

Example 1

The simulated oil is 80% toluene + 20% n-hexane (volume ratio) solution containing different phenols, in which the content of phenol is 100.1g/L, the content of o-cresol is 99.2g/L, and the content of 2,6-xylenol is 99.5g/L L. Take 500 mL of simulated oil, and extract and separate phenolic compounds with choline chloride at a temperature of 5°C.

Add 37.1g of choline chloride to the simulated oil for the first time, which is 50% of the molar number of phenol, stir for 10 minutes, and let stand for 5 minutes. The system is divided into two phases, and then separated to obtain the lower phase eutectic solvent and the upper phase. Simulated oil after phenol. The first extraction obtains 98.1g eutectic solvent, analysis composition (get a small amount of sample, dissolve phenol and neutral oil with dichloromethane, then adopt gas chromatography to analyze composition, calculate and obtain the amount of substance in eutectic solvent. The following analytical methods are the same, Not repeating description), wherein the content of neutral oil (referring toluene and n-hexane, the same below) is 9.9%. Under the conditions of a temperature of 80°C and a pressure of 0.02 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 10 minutes, and the mass content of the neutral oil was reduced to 0.5%. At 20°C, 5 times the volume of ethyl acetate was added to the eutectic solvent from which the neutral oil was removed, stirred for 5 minutes, then allowed to stand for 5 minutes, filtered and dried, and the choline chloride was recovered. For the above-mentioned ethyl acetate solution containing phenolic compounds, carry out distillation to recover ethyl acetate at 70° C. under negative pressure conditions, and obtain the product phenolic compounds (rich in phenol), which has a mass of 51.6 g and is composed of phenol 85.3 %, cresol 9.7%, xylenol 4.4%, neutral oil 0.6%, all are mass fractions (the following examples are the same).

For the second time, 38.4 g of choline chloride was added to the simulated oil after removing phenol for the first time, which was 60% of the molar number of cresol, stirred for 10 min, and left to stand for 5 min. The system was divided into two phases, and then separated to obtain the following Simulated oil after removal of phenol and o-cresol from phase eutectic solvent and upper phase. The second extraction yielded 89.8 g of eutectic solvent, which was analyzed to contain 9.1% neutral oil. Under the conditions of a temperature of 80°C and a pressure of 0.02 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 10 minutes, and the mass content of the neutral oil was reduced to 0.6%. At 20°C, 5 times the volume of ethyl acetate was added to the eutectic solvent from which the neutral oil was removed, stirred for 5 minutes, then allowed to stand for 5 minutes, filtered and dried, and the choline chloride was recovered. For the above-mentioned ethyl acetate solution containing phenolic compounds, at 70°C and under negative pressure conditions, carry out distillation to recover ethyl acetate, and obtain the product phenolic compounds (rich in cresol), its quality is 43.4g, and it consists of phenol 3.7%, cresol 87.5%, xylenol 8.0%, neutral oil 0.8%.

For the third time, 39.8 g of choline chloride was added to the simulated oil after removing phenol and cresol for the first and second time, which was 70% of the molar number of xylenol, stirred for 10 min, left standing for 5 min, and the system was divided It is two phases, and then liquid separation removes the lower eutectic solvent phase. Adopt silver nitrate titration analysis, do not find to have choline chloride in the upper phase oil phase. The third extraction yielded 45.7 g of eutectic solvent, which was analyzed to contain 2.1% neutral oil. Under the conditions of a temperature of 80°C and a pressure of 0.02 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 10 minutes, and the mass content of the neutral oil was reduced to 0.7%. At 20°C, 5 times the volume of ethyl acetate was added to the eutectic solvent from which the neutral oil was removed, stirred for 5 minutes, then allowed to stand for 5 minutes, filtered and dried, and the choline chloride was recovered. For the above-mentioned ethyl acetate solution containing phenolic compounds, carry out distillation to recover ethyl acetate at 70° C. under negative pressure conditions, and obtain the product phenolic compounds (rich in xylenol), which has a quality of 5.1 g and consists of 9.3% phenol, 9.3% cresol, 80.4% xylenol, 1.0% neutral oil.

Example 2

The simulated oil is 80% toluene + 20% n-hexane (volume ratio) solution containing different phenols, in which the content of phenol is 100.1g/L, the content of o-cresol is 99.2g/L, and the content of 2,6-xylenol is 99.5g/L L. Take 500 mL of simulated oil, and extract and separate phenolic compounds with tetramethylammonium chloride at a temperature of 5°C.

For the first time, add 29.1 g of tetramethylammonium chloride to the simulated oil, which is 50% of the molar number of phenol, stir for 10 minutes, and let it stand for 5 minutes. The system is divided into two phases, and then separated to obtain the lower phase eutectic solvent and the upper phase Simulated oil after removal of phenols. The first extraction yielded 96.1 g of eutectic solvent, and its composition was analyzed, wherein the neutral oil content was 11.2%. Under the conditions of a temperature of 80°C and a pressure of 0.02 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 10 minutes, and the mass content of the neutral oil was reduced to 0.4%. At 20°C, 6 times the volume of diethyl ether was added to the eutectic solvent from which neutral oil was removed, stirred for 5 minutes, then allowed to stand for 5 minutes, filtered and dried, and tetramethylammonium chloride was recovered. For the above ether solution containing phenolic compounds, distill and recover the ether at 70°C under negative pressure conditions, and obtain the product phenolic compounds (rich in phenol), which has a mass of 56.6g and consists of phenol containing 83.2%, formazan 11.5% phenol, 4.8% xylenol, 0.5% neutral oil.

For the second time, add 30.2 g of tetramethylammonium chloride to the simulated oil after removing phenol for the first time, which is 60% of the mole number of cresol, stir for 10 min, and let stand for 5 min. The system is divided into two phases, and then separated The liquid obtained the eutectic solvent in the lower phase and the simulated oil after removing phenol and o-cresol in the upper phase. The second extraction yielded 79.4 g of eutectic solvent, which was analyzed to contain 10.0% neutral oil. Under the conditions of a temperature of 80°C and a pressure of 0.02 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 10 minutes, and the mass content of the neutral oil was reduced to 0.6%. At 20°C, 6 times the volume of diethyl ether was added to the eutectic solvent from which neutral oil was removed, stirred for 5 minutes, then allowed to stand for 5 minutes, filtered and dried, and tetramethylammonium chloride was recovered. For the above ether solution containing phenolic compounds, carry out distillation to recover the ether at 70°C under negative pressure conditions, and obtain the product phenolic compounds (rich in cresol), which has a quality of 41.6g and consists of 3.5% phenol, cresol 89.5% phenol, 6.0% xylenol, 1.0% neutral oil.

For the third time, 31.3 g of tetramethylammonium chloride was added to the simulated oil after removing phenol and cresol for the first and second time, which was 70% of the molar number of xylenol, stirred for 10 min, and left standing for 5 min. The system is divided into two phases, and then liquid separation removes the lower eutectic solvent phase. Adopt silver nitrate titration analysis, do not find tetramethylammonium chloride in the upper phase oil phase. The third extraction yielded 47.5 g of eutectic solvent, which was analyzed to contain 5.5% neutral oil. Under the conditions of a temperature of 80°C and a pressure of 0.02 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 10 minutes, and the mass content of the neutral oil was reduced to 0.4%. At 20°C, 6 times the volume of diethyl ether was added to the eutectic solvent from which neutral oil was removed, stirred for 5 minutes, then allowed to stand for 5 minutes, filtered and dried, and tetramethylammonium chloride was recovered. For the above ether solution containing phenolic compounds, carry out distillation to recover ether at 70°C under negative pressure conditions, and obtain the product phenolic compounds (rich in xylenol), which has a quality of 13.7g and consists of phenol 2.9%, Cresol 1.8%, xylenol 94.5%, neutral oil 0.8%.

Example 3

The simulated oil is 80% toluene + 20% n-hexane (volume ratio) solution containing different phenols, in which the content of phenol is 100.1g/L, the content of o-cresol is 99.2g/L, and the content of 2,6-xylenol is 99.5g/L L. Take 500 g of simulated oil, and extract and separate phenolic compounds with tetraethylammonium chloride at a temperature of 5°C.

For the first time, add 44.1 g of tetraethylammonium chloride to the simulated oil, which is 50% of the molar number of phenol, stir for 10 minutes, and let stand for 5 minutes. The system is divided into two phases, and then separated to obtain the lower phase eutectic solvent and the upper phase Simulated oil after removal of phenols. The first extraction yielded 117.2 g of eutectic solvent, and the composition was analyzed, and the neutral oil content was 10.3%. Under the conditions of a temperature of 80°C and a pressure of 0.02 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 10 minutes, and the mass content of the neutral oil was reduced to 0.4%. At 20°C, 5 times the volume of ethyl acetate was added to the eutectic solvent from which the neutral oil was removed, stirred for 5 minutes, then allowed to stand for 5 minutes, filtered and dried, and tetraethylammonium chloride was recovered. For the above-mentioned ethyl acetate solution containing phenolic compounds, carry out distillation to recover ethyl acetate at 70°C under negative pressure conditions, and obtain the product phenolic compounds (rich in phenol), which has a mass of 61.4g and is composed of phenol 78.1 %, cresol 15.2%, xylenol 6.0%, neutral oil 0.7%.

For the second time, 45.6 g of tetraethylammonium chloride was added to the simulated oil after removing phenol for the first time, which was 60% of the mole number of cresol, stirred for 10 min, and left to stand for 5 min. The system was divided into two phases, and then separated The liquid obtained the eutectic solvent in the lower phase and the simulated oil after removing phenol and o-cresol in the upper phase. The second extraction yielded 97.3 g of eutectic solvent, which was analyzed to contain 9.1% neutral oil. Under the conditions of a temperature of 80°C and a pressure of 0.02 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 10 minutes, and the mass content of the neutral oil was reduced to 0.3%. At 20°C, 5 times the volume of ethyl acetate was added to the eutectic solvent from which the neutral oil was removed, stirred for 5 minutes, then allowed to stand for 5 minutes, filtered and dried, and tetraethylammonium chloride was recovered. For the above-mentioned ethyl acetate solution containing phenolic compounds, at 70°C and under negative pressure conditions, carry out distillation to recover ethyl acetate, and obtain the product phenolic compounds (rich in cresol), its quality is 43.1g, and it consists of phenol 2.0%, cresol 83.6%, xylenol 13.9%, neutral oil 0.5%.

For the third time, 47.3 g of tetraethylammonium chloride was added to the simulated oil after removing phenol and cresol for the first and second time, which was 70% of the molar number of xylenol, stirred for 10 min, and left standing for 5 min. The system is divided into two phases, and then liquid separation removes the lower eutectic solvent phase. Adopt silver nitrate titration analysis, do not find tetraethylammonium chloride in the upper phase oil phase. The third extraction yielded 83.6 g of eutectic solvent, which was analyzed to contain 7.7% neutral oil. Under the conditions of a temperature of 80°C and a pressure of 0.02 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 10 minutes, and the mass content of the neutral oil was reduced to 0.3%. At 20°C, 5 times the volume of ethyl acetate was added to the eutectic solvent from which the neutral oil was removed, stirred for 5 minutes, then allowed to stand for 5 minutes, filtered and dried, and tetraethylammonium chloride was recovered. For the above-mentioned ethyl acetate solution containing phenolic compounds, carry out distillation to recover ethyl acetate at 70° C. under negative pressure conditions, and obtain the product phenolic compounds (rich in xylenol), which has a quality of 30.1 g and consists of 1.1% phenol, 2.2% cresol, 96.1% xylenol, 0.6% neutral oil.

Example 4

The simulated oil is 80% toluene + 20% n-hexane (volume ratio) solution containing different phenols, in which the content of phenol is 100.1g/L, the content of o-cresol is 99.2g/L, and the content of 2,6-xylenol is 99.5g/L L. Take 500 g of simulated oil, and extract and separate phenolic compounds with methyltriethylammonium chloride at a temperature of 5°C.

Add methyltriethylammonium chloride 40.3g to the simulated oil for the first time, which is 50% of the molar number of phenol, stir for 10min, leave standstill for 5min, the system is divided into two phases, and then separate liquids to obtain the lower phase eutectic solvent and Simulated oil after removal of phenol in the upper phase. The first extraction yielded 109.2 g of eutectic solvent, and its composition was analyzed to find that the neutral oil content was 10.4%. Under the conditions of a temperature of 80°C and a pressure of 0.02 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 10 minutes, and the mass content of the neutral oil was reduced to 0.4%. At 20°C, 5 times the volume of ethyl acetate was added to the eutectic solvent from which the neutral oil was removed, stirred for 5 minutes, then allowed to stand for 5 minutes, filtered and dried, and methyltriethylammonium chloride was recovered. For the above-mentioned ethyl acetate solution containing phenolic compounds, carry out distillation to recover ethyl acetate at 70°C under negative pressure conditions, and obtain the product phenolic compounds (rich in phenol), which has a mass of 57.8g and is composed of phenol 82.5 %, cresol 10.4%, xylenol 6.4%, neutral oil 0.7%.

For the second time, 41.8 g of methyltriethylammonium chloride was added to the simulated oil after removing phenol for the first time, which was 60% of the mole number of cresol, stirred for 10 minutes, and left to stand for 5 minutes. The system was divided into two phases. Then, liquid separation was performed to obtain the eutectic solvent in the lower phase and the simulated oil after removing phenol and o-cresol in the upper phase. The second extraction yielded 91.6 g of eutectic solvent, which was analyzed to contain 9.1% neutral oil. Under the conditions of a temperature of 80°C and a pressure of 0.02 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 10 minutes, and the mass content of the neutral oil was reduced to 0.3%. At 20°C, 5 times the volume of ethyl acetate was added to the eutectic solvent from which the neutral oil was removed, stirred for 5 minutes, then allowed to stand for 5 minutes, filtered and dried, and methyltriethylammonium chloride was recovered. For the above-mentioned ethyl acetate solution containing phenolic compounds, at 70°C and under negative pressure, carry out distillation to recover ethyl acetate, and obtain the product phenolic compounds (rich in cresol), which has a mass of 41.8g and consists of phenol 1.7%, cresol 91.7%, xylenol 5.9%, neutral oil 0.7%.

For the third time, add 43.3 g of methyltriethylammonium chloride to the simulated oil after removing phenol and cresol for the first and second time, which is 70% of the mole number of xylenol, stir for 10 min, and let stand After 5 minutes, the system was divided into two phases, and then the eutectic solvent phase was removed from the lower phase by liquid separation. Adopt silver nitrate titration analysis, do not find methyltriethylammonium chloride in the upper phase oil phase. The third extraction yielded 80.2 g of eutectic solvent, which was analyzed to contain 7.8% neutral oil. Under the conditions of a temperature of 80°C and a pressure of 0.02 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 10 minutes, and the mass content of the neutral oil was reduced to 0.3%. At 20°C, 5 times the volume of ethyl acetate was added to the eutectic solvent from which the neutral oil was removed, stirred for 5 minutes, then allowed to stand for 5 minutes, filtered and dried, and methyltriethylammonium chloride was recovered. For the above-mentioned ethyl acetate solution containing phenolic compounds, at 70°C and under negative pressure conditions, carry out distillation to recover ethyl acetate, and obtain the product phenolic compounds (rich in xylenol), its quality is 30.8g, and it consists of 1.1% phenol, 2.6% cresol, 95.7% xylenol, 0.6% neutral oil.

Example 5

The simulated oil is 80% toluene + 20% n-hexane (volume ratio) solution containing different phenols, in which the content of phenol is 100.1g/L, the content of o-cresol is 99.2g/L, and the content of 2,6-xylenol is 99.5g/L L. Take 500 g of simulated oil, and extract and separate phenolic compounds with tetraethylammonium bromide at a temperature of 5°C.

Add 55.9 g of tetraethylammonium bromide to the simulated oil for the first time, which is 50% of the molar number of phenol, stir for 10 minutes, and let stand for 5 minutes. The system is divided into two phases, and then separated to obtain the lower phase eutectic solvent and the upper phase Simulated oil after removal of phenols. The first extraction yielded 127.2 g of eutectic solvent, and the composition was analyzed, and the neutral oil content was 9.0%. Under the conditions of a temperature of 80°C and a pressure of 0.02 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 10 minutes, and the mass content of the neutral oil was reduced to 0.4%. At 20°C, 5 times the volume of ethyl acetate was added to the eutectic solvent from which the neutral oil was removed, stirred for 5 minutes, then allowed to stand for 5 minutes, filtered and dried, and tetraethylammonium bromide was recovered. For the above-mentioned ethyl acetate solution containing phenolic compounds, carry out distillation to recover ethyl acetate at 70°C under negative pressure conditions, and obtain the product phenolic compounds (rich in phenol), which has a mass of 60.3g and is composed of phenol 79.4 %, cresol 13.0%, xylenol 7.0%, neutral oil 0.6%.

For the second time, 57.8 g of tetraethylammonium bromide was added to the simulated oil after removing phenol for the first time, which was 60% of the mole number of cresol, stirred for 10 min, and left to stand for 5 min. The system was divided into two phases, and then separated The liquid obtained the eutectic solvent in the lower phase and the simulated oil after removing phenol and o-cresol in the upper phase. The second extraction yielded 104.5 g of eutectic solvent, which was analyzed to contain 7.3% neutral oil. Under the conditions of a temperature of 80°C and a pressure of 0.02 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 10 minutes, and the mass content of the neutral oil was reduced to 0.3%. At 20°C, 5 times the volume of ethyl acetate was added to the eutectic solvent from which the neutral oil was removed, stirred for 5 minutes, then allowed to stand for 5 minutes, filtered and dried, and tetraethylammonium bromide was recovered. For the above-mentioned ethyl acetate solution containing phenolic compounds, carry out distillation and recovery of ethyl acetate at 70°C under negative pressure conditions, and obtain the product phenolic compounds (rich in cresol), which has a mass of 39.4g and consists of phenol 1.4%, cresol 90.5%, xylenol 7.6%, neutral oil 0.5%.

For the third time, add 60.0 g of tetraethylammonium bromide to the simulated oil after removing phenol and cresol for the first and second time, which is 70% of the molar number of xylenol, stir for 10 min, and let stand for 5 min. The system is divided into two phases, and then liquid separation removes the lower eutectic solvent phase. Adopt silver nitrate titration analysis, do not find tetraethylammonium bromide in the upper phase oil phase. The third extraction yielded 95.3 g of eutectic solvent, which was analyzed to contain 6.3% neutral oil. Under the conditions of a temperature of 80°C and a pressure of 0.02 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 10 minutes, and the mass content of the neutral oil was reduced to 0.3%. At 20°C, 5 times the volume of ethyl acetate was added to the eutectic solvent from which the neutral oil was removed, stirred for 5 minutes, then allowed to stand for 5 minutes, filtered and dried, and tetraethylammonium bromide was recovered. For the above-mentioned ethyl acetate solution containing phenolic compounds, at 70°C and under negative pressure conditions, carry out distillation to recover ethyl acetate, and obtain the product phenolic compounds (rich in xylenol), its quality is 29.5g, and it consists of 0.5% phenol, 2.2% cresol, 96.7% xylenol, 0.6% neutral oil.

Example 6

The simulated oil is a 90% toluene + 10% n-hexane (volume ratio) solution containing different phenols, in which the phenol content is 100.6g/L, the o-cresol content is 60.2g/L, and the 2,6-xylenol content is 60.0g/L L. Take 500 g of simulated oil, and extract and separate phenolic compounds with tetraethylammonium chloride at a temperature of 15°C.

Add 35.4 g of tetraethylammonium chloride to the simulated oil for the first time, which is 40% of the molar number of phenol, stir for 10 minutes, and let stand for 5 minutes. The system is divided into two phases, and then separated to obtain the lower phase eutectic solvent and the upper phase Simulated oil after removal of phenols. The first extraction yielded 99.8 g of eutectic solvent, and the composition was analyzed, and the neutral oil content was 11.5%. Under the conditions of a temperature of 80°C and a pressure of 0.015 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 10 minutes, and the mass content of the neutral oil was reduced to 0.3%. At 15°C, 6 times the volume of ethyl acetate was added to the eutectic solvent from which the neutral oil was removed, stirred for 5 minutes, then allowed to stand for 5 minutes, filtered and dried, and tetraethylammonium chloride was recovered. For the above-mentioned ethyl acetate solution containing phenolic compounds, carry out distillation to recover ethyl acetate at 70°C under negative pressure conditions, and obtain the product phenolic compounds (rich in phenol), which has a mass of 53.2g and is composed of phenol 85.6 %, cresol 8.3%, xylenol 5.6%, neutral oil 0.5%.

For the second time, add 32.3 g of tetraethylammonium chloride to the simulated oil after removing phenol for the first time, which is 70% of the mole number of cresol, stir for 10 min, and let stand for 5 min. The system is divided into two phases, and then separated The liquid obtained the eutectic solvent in the lower phase and the simulated oil after removing phenol and o-cresol in the upper phase. The second extraction yielded 65.3 g of eutectic solvent, which was analyzed to contain 9.2% neutral oil. Under the conditions of a temperature of 80°C and a pressure of 0.015 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 10 minutes, and the mass content of the neutral oil was reduced to 0.3%. At 20°C, 6 times the volume of ethyl acetate was added to the eutectic solvent from which the neutral oil was removed, stirred for 5 minutes, then allowed to stand for 5 minutes, filtered and dried, and tetraethylammonium chloride was recovered. For the above-mentioned ethyl acetate solution containing phenolic compounds, carry out distillation to recover ethyl acetate at 70° C. under negative pressure conditions, and obtain the product phenolic compounds (rich in cresol), which has a mass of 27.2 g and consists of phenol 12.6%, cresol 79.5%, xylenol 7.4%, neutral oil 0.5%.

For the third time, 32.6 g of tetraethylammonium chloride was added to the simulated oil after removing phenol and cresol for the first and second time, which was 80% of the molar number of xylenol, stirred for 10 min, and left standing for 5 min. The system is divided into two phases, and then liquid separation removes the lower eutectic solvent phase. Adopt silver nitrate titration analysis, do not find tetraethylammonium chloride in the upper phase oil phase. The third extraction yielded 52.1 g of eutectic solvent, which was analyzed to contain 7.5% neutral oil. Under the conditions of a temperature of 80°C and a pressure of 0.015 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 10 minutes, and the mass content of the neutral oil was reduced to 0.3%. At 20°C, 5 times the volume of ethyl acetate was added to the eutectic solvent from which the neutral oil was removed, stirred for 5 minutes, then allowed to stand for 5 minutes, filtered and dried, and tetraethylammonium chloride was recovered. For the above-mentioned ethyl acetate solution containing phenolic compounds, carry out distillation to recover ethyl acetate at 70° C. under negative pressure conditions, and obtain the product phenolic compounds (rich in xylenol), which has a quality of 15.6 g and consists of 2.8% phenol, 4.4% cresol, 92.1% xylenol, 0.7% neutral oil.

Example 7

The simulated oil is 80% toluene+20% n-hexane (volume ratio) solution containing different phenols, in which phenol content is 102.4g/L, o-cresol content is 61.2g/L, 2,6-xylenol content is 60.4g/L L. Take 500mL of simulated oil, extract and separate phenolic compounds with tetraethylammonium chloride at a temperature of 20°C, and repeat the test of the extractant.

(1) The first use of extractant test

For the first time, add 45.1 g of tetraethylammonium chloride to the simulated oil, which is 50% of the molar number of phenol, stir for 10 minutes, and let stand for 5 minutes. The system is divided into two phases, and then separated to obtain the lower phase eutectic solvent and the upper phase. Simulated oil after phenol removal. The first extraction yielded 109.3 g of eutectic solvent, and the composition was analyzed, and the neutral oil content was 9.7%. Under the conditions of a temperature of 90°C and a pressure of 0.05 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 20 minutes, and the mass content of the neutral oil was reduced to 0.4%. At 15°C, 6 times the volume of ethyl acetate was added to the eutectic solvent from which the neutral oil was removed, stirred for 5 minutes, then allowed to stand for 5 minutes, filtered and dried, and tetraethylammonium chloride was recovered. For the above-mentioned ethyl acetate solution containing phenolic compounds, carry out distillation to recover ethyl acetate at 70° C. under negative pressure conditions, and obtain the product phenolic compounds (rich in phenol), which has a mass of 53.9 g and is composed of phenol 85.7 %, cresol 8.7%, xylenol 5.0%, neutral oil 0.6%.

For the second time, 28.1 g of tetraethylammonium chloride was added to the simulated oil after removing phenol for the first time, which was 60% of the mole number of cresol, stirred for 10 minutes, and left to stand for 5 minutes. The system was divided into two phases, and then separated The liquid obtained the eutectic solvent in the lower phase and the simulated oil after removing phenol and o-cresol in the upper phase. The second extraction yielded 60.6 g of eutectic solvent, which was analyzed to contain 9.2% neutral oil. Under the conditions of a temperature of 80°C and a pressure of 0.05 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 20 minutes, and the mass content of the neutral oil was reduced to 0.3%. At 20°C, 6 times the volume of ethyl acetate was added to the eutectic solvent from which the neutral oil was removed, stirred for 5 minutes, then allowed to stand for 5 minutes, filtered and dried, and tetraethylammonium chloride was recovered. For the above-mentioned ethyl acetate solution containing phenolic compounds, carry out distillation to recover ethyl acetate at 70° C. under negative pressure conditions, and obtain the product phenolic compounds (rich in cresol), which has a mass of 27.0 g and consists of phenol 12.6%, cresol 79.8%, xylenol 7.0%, neutral oil 0.6%.

For the third time, 28.7 g of tetraethylammonium chloride was added to the simulated oil after removing phenol and cresol for the first and second time, which was 70% of the molar number of xylenol, stirred for 10 min, and left standing for 5 min. The system is divided into two phases, and then liquid separation removes the lower eutectic solvent phase. Adopt silver nitrate titration analysis, do not find tetraethylammonium chloride in the upper phase oil phase. The third extraction yielded 46.9 g of eutectic solvent, which was analyzed to contain 7.1% neutral oil. Under the conditions of temperature 90° C. and pressure 0.04 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 20 minutes, and the mass content of neutral oil was reduced to 0.3%. At 20°C, 5 times the volume of ethyl acetate was added to the eutectic solvent from which the neutral oil was removed, stirred for 5 minutes, then allowed to stand for 5 minutes, filtered and dried, and tetraethylammonium chloride was recovered. For the above-mentioned ethyl acetate solution containing phenolic compounds, carry out distillation to recover ethyl acetate at 70° C. under negative pressure conditions, and obtain the product phenolic compounds (rich in xylenol), which has a quality of 15.1 g and consists of 3.3% phenol, 5.5% cresol, 90.7% xylenol, 0.5% neutral oil.

(2) Repeated use of extractant test

The extractant tetraethylammonium chloride recovered above was dried and then reused. Take 500mL of the above-mentioned simulated oil, and add tetraethylammonium chloride to the simulated oil three times respectively, the addition amount and operating conditions are the same as those of the first test using the extractant.

Add 45.1g of tetraethylammonium chloride to the simulated oil for the first time, through the same treatment with the first addition of tetraethylammonium chloride in the extractant test for the first time, to obtain the product phenolic compound (rich in phenol) , its quality is 53.2g, and its composition is 85.4% of phenol, 9.0% of cresol, 4.9% of xylenol, and 0.7% of neutral oil.

For the second time, 28.1 g of tetraethylammonium chloride is added to the simulated oil after removing phenol for the first time, and after the same treatment as that of adding tetraethylammonium chloride for the second time in the first use of the extractant test, the obtained The product phenolic compound (rich in cresol) has a mass of 27.2 g and consists of 12.9% phenol, 79.6% cresol, 6.8% xylenol and 0.7% neutral oil.

For the third time, 28.7 g of tetraethylammonium chloride was added to the simulated oil after removing phenol and cresol for the first time and the second time. Ammonium after the same treatment, to obtain the product phenolic compound (rich in xylenol), its quality is 15.1g, composed of phenol 3.3%, cresol 5.4%, xylenol 90.7%, neutral oil 0.6%.

(3) Repeated use of extractant test

(2) Repeat the test for the third time after drying the extractant tetraethylammonium chloride obtained in the repeated test. Take 500mL of the above-mentioned simulated oil, and add tetraethylammonium chloride to the simulated oil three times respectively, the addition amount and operating conditions are the same as those of the first repeated test.

Add 45.1g of tetraethylammonium chloride to the simulated oil for the first time, through the same treatment with the first addition of tetraethylammonium chloride in the extractant test for the first time, to obtain the product phenolic compound (rich in phenol) , its quality is 53.3g, and it is composed of 85.2% phenol, 9.4% cresol, 4.7% xylenol, and 0.7% neutral oil.

For the second time, 28.1 g of tetraethylammonium chloride is added to the simulated oil after removing phenol for the first time, and after the same treatment as that of adding tetraethylammonium chloride for the second time in the first use of the extractant test, the obtained The product phenolic compound (rich in cresol) has a mass of 27.4g and consists of 12.9% phenol, 79.2% cresol, 7.2% xylenol and 0.6% neutral oil.

For the third time, 28.7 g of tetraethylammonium chloride was added to the simulated oil after removing phenol and cresol for the first time and the second time. Ammonium after the same treatment, to obtain product phenolic compound (rich in xylenol), its quality is 14.8g, composed of phenol 3.1%, cresol 5.5%, xylenol 90.9%, neutral oil 0.5%.

Example 8

The simulated oil is a 90% toluene + 10% n-hexane (volume ratio) solution containing different phenols, in which the phenol content is 100.6g/L, the o-cresol content is 60.2g/L, and the 2,6-xylenol content is 60.0g/L L. Take 500 g of simulated oil, and extract and separate phenolic compounds with tetraethylammonium chloride at a temperature of 15°C.

Add 26.6g of tetraethylammonium chloride to the simulated oil for the first time, which is 30% of the molar number of phenol, stir for 10 minutes, and let stand for 5 minutes. The system is divided into two phases, and then separated to obtain the lower phase eutectic solvent and the upper phase Simulated oil after removal of phenols. The first extraction yielded 82.4 g of eutectic solvent, and the composition was analyzed, and the neutral oil content was 12.0%. Under the conditions of a temperature of 80°C and a pressure of 0.015 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 20 minutes, and the mass content of the neutral oil was reduced to 0.3%. At 15°C, 7 times the volume of methyl formate was added to the eutectic solvent from which the neutral oil was removed, stirred for 5 minutes, then allowed to stand for 5 minutes, filtered and dried, and tetraethylammonium chloride was recovered. For the above-mentioned methyl formate solution containing phenolic compounds, at 70°C and under negative pressure conditions, carry out distillation to recover methyl formate, and obtain the product phenolic compounds (rich in phenol), its quality is 46.2g, and it is composed of phenol 95.4 %, cresol 3.0%, xylenol 1.1%, neutral oil 0.5%.

For the second time, add 32.3 g of tetraethylammonium chloride to the simulated oil after removing phenol for the first time, which is 70% of the mole number of cresol, stir for 10 minutes, and let stand for 5 minutes. The system is divided into two phases, and then separated. The eutectic solvent in the lower phase and the simulated oil after removal of phenol and o-cresol in the upper phase were obtained. The second extraction yielded 73.5 g of eutectic solvent, which was analyzed to contain 10.1% neutral oil. Under the conditions of a temperature of 80°C and a pressure of 0.015 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 20 minutes, and the mass content of the neutral oil was reduced to 0.4%. At 20°C, 7 times the volume of methyl formate was added to the eutectic solvent from which the neutral oil was removed, stirred for 5 minutes, then allowed to stand for 5 minutes, filtered and dried, and tetraethylammonium chloride was recovered. For the above-mentioned methyl formate solution containing phenolic compounds, at 70°C and under negative pressure conditions, carry out distillation to recover methyl formate, and obtain the product phenolic compounds (rich in cresol), its quality is 34.1g, and it consists of phenol 14.3%, cresol 72.0%, xylenol 13.2%, neutral oil 0.5%.

For the third time, 36.6 g of tetraethylammonium chloride was added to the simulated oil after removing phenol and cresol for the first and second time, which was 90% of the molar number of xylenol, stirred for 10 min, and left standing for 5 min. The system is divided into two phases, and then liquid separation removes the lower eutectic solvent phase. Adopt silver nitrate titration analysis, do not find tetraethylammonium chloride in the upper phase oil phase. The third extraction yielded 56.0 g of eutectic solvent, which was analyzed to contain 7.0% neutral oil. Under the conditions of a temperature of 80°C and a pressure of 0.015 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 20 minutes, and the mass content of the neutral oil was reduced to 0.3%. At 20°C, 7 times the volume of methyl formate was added to the eutectic solvent from which the neutral oil was removed, stirred for 5 minutes, then allowed to stand for 5 minutes, filtered and dried, and tetraethylammonium chloride was recovered. For the above-mentioned methyl formate solution containing phenolic compounds, at 70°C and under negative pressure conditions, carry out distillation to reclaim methyl formate, and obtain the product phenolic compounds (rich in xylenol), its quality is 15.5g, and it consists of 3.2% phenol, 4.2% cresol, 92.1% xylenol, 0.5% neutral oil.

Example 9

The simulated oil is 80% toluene + 20% n-hexane (volume ratio) solution containing different phenols, in which the content of phenol is 100.1g/L, the content of o-cresol is 99.2g/L, and the content of 2,6-xylenol is 99.5g/L L. Take 500 g of simulated oil, and extract and separate phenolic compounds with tetraethylammonium chloride at a temperature of 5°C.

Add 52.9 g of tetraethylammonium chloride to the simulated oil for the first time, which is 60% of the molar number of phenol, stir for 10 minutes, and let stand for 5 minutes. The system is divided into two phases, and then separated to obtain the lower phase eutectic solvent and the upper phase Simulated oil after removal of phenols. The first extraction yielded 130.7 g of eutectic solvent, and the composition was analyzed, and the neutral oil content was 9.8%. Under the conditions of a temperature of 70°C and a pressure of 0.01 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 10 minutes, and the mass content of the neutral oil was reduced to 0.4%. At 20°C, 7 times the volume of diethyl ether was added to the eutectic solvent from which the neutral oil was removed, stirred for 5 minutes, then allowed to stand for 5 minutes, filtered and dried, and tetraethylammonium chloride was recovered. For the above-mentioned ether solution containing phenolic compounds, distill and recover the ether at 60°C under negative pressure conditions, and obtain the product phenolic compounds (rich in phenol), which has a mass of 65.3g and consists of phenol 73.6%, cresol 19.8%, xylenol 6.1%, neutral oil 0.5%.

For the second time, add 41.8g of tetraethylammonium chloride to the simulated oil after the first removal of phenol, which is 55% of the mole number of cresol, stir for 10min, and let stand for 5min. The system is divided into two phases, and then separated. The eutectic solvent in the lower phase and the simulated oil after removal of phenol and o-cresol in the upper phase were obtained. The second extraction yielded 88.8 g of eutectic solvent, which was analyzed to contain 9% neutral oil. Under the conditions of a temperature of 70°C and a pressure of 0.01 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 10 minutes, and the mass content of the neutral oil was reduced to 0.4%. At 20°C, 7 times the volume of diethyl ether was added to the eutectic solvent from which the neutral oil was removed, stirred for 5 minutes, then allowed to stand for 5 minutes, filtered and dried, and tetraethylammonium chloride was recovered. For the above ether solution containing phenolic compounds, carry out distillation to recover the ether at 70°C under negative pressure conditions, and obtain the product phenolic compounds (rich in cresol), which has a quality of 39.2g and consists of 1.8% phenol, cresol 83.1% phenol, 14.7% xylenol, 0.4% neutral oil.

For the third time, 47.3 g of tetraethylammonium chloride was added to the simulated oil after removing phenol and cresol for the first and second time, which was 70% of the molar number of xylenol, stirred for 10 min, and left standing for 5 min. The system is divided into two phases, and then liquid separation removes the lower eutectic solvent phase. Adopt silver nitrate titration analysis, do not find tetraethylammonium chloride in the upper phase oil phase. The third extraction yielded 83.4 g of eutectic solvent, which was analyzed to contain 7.5% neutral oil. Under the conditions of a temperature of 70°C and a pressure of 0.01 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 10 minutes, and the mass content of the neutral oil was reduced to 0.3%. At 20°C, 7 times the volume of diethyl ether was added to the eutectic solvent from which the neutral oil was removed, stirred for 5 minutes, then allowed to stand for 5 minutes, filtered and dried, and tetraethylammonium chloride was recovered. For the above ether solution containing phenolic compounds, carry out distillation to recover the ether at 70°C under negative pressure conditions, and obtain the product phenolic compounds (rich in xylenol), which has a quality of 30.0g and consists of 1.0% phenol, 2.5% cresol, 96.0% xylenol, 0.5% neutral oil.

Example 10

The simulated oil is 80% toluene + 20% n-hexane (volume ratio) solution containing different phenols, in which the content of phenol is 100.1g/L, the content of o-cresol is 99.2g/L, and the content of 2,6-xylenol is 99.5g/L L. Take 500 mL of simulated oil, and extract and separate phenolic compounds with tetramethylammonium chloride at a temperature of 5°C.

For the first time, add 29.1 g of tetramethylammonium chloride to the simulated oil, which is 50% of the molar number of phenol, stir for 2 minutes, and let it stand for 20 minutes. The system is divided into two phases, and then separated to obtain the lower phase eutectic solvent and the upper phase. Simulated oil after removal of phenols. The first extraction yielded 96.2 g of eutectic solvent, and its composition was analyzed, wherein the neutral oil content was 11.1%. Under the conditions of temperature 90° C. and pressure 0.06 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 20 minutes, and the mass content of neutral oil was reduced to 0.4%. At 20°C, 6 times the volume of isopropyl ether was added to the eutectic solvent from which the neutral oil was removed, stirred for 5 minutes, then allowed to stand for 5 minutes, filtered and dried, and tetramethylammonium chloride was recovered. For the above-mentioned isopropyl ether solution containing phenolic compounds, distill and recover the isopropyl ether at 70°C under negative pressure conditions, and obtain the product phenolic compounds (rich in phenol), which has a mass of 56.7g and consists of phenol-containing 83.0%, cresol 11.7%, xylenol 4.9%, neutral oil 0.4%.

For the second time, add 30.2 g of tetramethylammonium chloride to the simulated oil after removing phenol for the first time, which is 60% of the mole number of cresol, stir for 2 min, and let stand for 20 min. The system is divided into two phases, and then separated The liquid obtained the eutectic solvent in the lower phase and the simulated oil after removing phenol and o-cresol in the upper phase. The second extraction yielded 79.2 g of eutectic solvent, which was analyzed to contain 9.9% neutral oil. Under the conditions of temperature 90° C. and pressure 0.06 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 20 minutes, and the mass content of neutral oil was reduced to 0.6%. At 20°C, 6 times the volume of isopropyl ether was added to the eutectic solvent from which the neutral oil was removed, stirred for 5 minutes, then allowed to stand for 5 minutes, filtered and dried, and tetramethylammonium chloride was recovered. For the above-mentioned isopropyl ether solution containing phenolic compounds, carry out distillation to recover isopropyl ether at 70°C under negative pressure conditions, and obtain the product phenolic compounds (rich in cresol), which has a mass of 41.5g and consists of phenol 3.5%, cresol 89.8%, xylenol 6.0%, neutral oil 0.7%.

For the third time, 31.3 g of tetramethylammonium chloride was added to the simulated oil after removing phenol and cresol for the first and second time, which was 70% of the molar number of xylenol, stirred for 2 minutes, and left standing for 20 minutes. The system is divided into two phases, and then liquid separation removes the lower eutectic solvent phase. Adopt silver nitrate titration analysis, do not find tetramethylammonium chloride in the upper phase oil phase. The third extraction yielded 47.4 g of eutectic solvent, which was analyzed to contain 5.4% neutral oil. Under the conditions of temperature 90° C. and pressure 0.06 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 20 minutes, and the mass content of neutral oil was reduced to 0.4%. At 20°C, 6 times the volume of isopropyl ether was added to the eutectic solvent from which the neutral oil was removed, stirred for 5 minutes, then allowed to stand for 5 minutes, filtered and dried, and tetramethylammonium chloride was recovered. For the above-mentioned isopropyl ether solution containing phenolic compounds, at 70°C and under negative pressure conditions, carry out distillation to recover isopropyl ether, and obtain the product phenolic compounds (rich in xylenol), its quality is 13.6g, and it consists of 2.8% phenol, 1.8% cresol, 94.7% xylenol, 0.7% neutral oil.

Example 11

The simulated oil is 80% toluene + 20% n-hexane (volume ratio) solution containing different phenols, in which the content of phenol is 100.1g/L, the content of o-cresol is 99.2g/L, and the content of 2,6-xylenol is 99.5g/L L. Take 500 mL of simulated oil, and extract and separate phenolic compounds with tetramethylammonium chloride at a temperature of 5°C.

For the first time, add 29.1 g of tetramethylammonium chloride to the simulated oil, which is 50% of the molar number of phenol, stir for 30 minutes, and let stand for 20 minutes. The system is divided into two phases, and then separated to obtain the lower phase eutectic solvent and the upper phase Simulated oil after removal of phenols. The first extraction yielded 96.0 g of eutectic solvent, and its composition was analyzed, wherein the neutral oil content was 11.1%. Under the conditions of a temperature of 80°C and a pressure of 0.02 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 10 minutes, and the mass content of the neutral oil was reduced to 0.4%. At 20°C, 7 times the volume of n-butyl ether was added to the eutectic solvent from which the neutral oil was removed, stirred for 10 minutes, then allowed to stand for 10 minutes, filtered and dried, and tetramethylammonium chloride was recovered. For the above-mentioned n-butyl ether solution containing phenolic compounds, at 70°C and under negative pressure conditions, carry out distillation to recover n-butyl ether, and obtain the product phenolic compounds (rich in phenol), which has a mass of 56.4g and consists of phenol-containing 83.2%, cresol 11.5%, xylenol 4.8%, neutral oil 0.5%.

For the second time, 30.2 g of tetramethylammonium chloride was added to the simulated oil after removing phenol for the first time, which was 60% of the mole number of cresol, stirred for 30 minutes, and left to stand for 20 minutes. The system was divided into two phases, and then separated The liquid obtained the eutectic solvent in the lower phase and the simulated oil after removing phenol and o-cresol in the upper phase. The second extraction yielded 79.5 g of eutectic solvent, which was analyzed to contain 9.9% neutral oil. Under the conditions of a temperature of 80°C and a pressure of 0.02 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 10 minutes, and the mass content of the neutral oil was reduced to 0.6%. At 20°C, 7 times the volume of n-butyl ether was added to the eutectic solvent from which the neutral oil was removed, stirred for 10 minutes, then allowed to stand for 10 minutes, filtered and dried, and tetramethylammonium chloride was recovered. For the above-mentioned n-butyl ether solution containing phenolic compounds, carry out distillation to recover n-butyl ether at 70°C and under negative pressure conditions, and obtain the product phenolic compounds (rich in cresol), which has a mass of 41.5g and consists of phenol 3.5%, cresol 89.8%, xylenol 6.0%, neutral oil 0.7%.

For the third time, 31.3 g of tetramethylammonium chloride was added to the simulated oil after removing phenol and cresol for the first and second time, which was 70% of the molar number of xylenol, stirred for 30 min, and left standing for 20 min. The system is divided into two phases, and then liquid separation removes the lower eutectic solvent phase. Adopt silver nitrate titration analysis, do not find tetramethylammonium chloride in the upper phase oil phase. The third extraction yielded 47.7 g of eutectic solvent, which was analyzed to contain 5.5% neutral oil. Under the conditions of a temperature of 80°C and a pressure of 0.02 atm, the neutral oil in the obtained eutectic solvent was removed by rotary evaporation. The evaporation time was 10 minutes, and the mass content of the neutral oil was reduced to 0.4%. At 20°C, 7 times the volume of n-butyl ether was added to the eutectic solvent from which the neutral oil was removed, stirred for 10 minutes, then allowed to stand for 10 minutes, filtered and dried, and tetramethylammonium chloride was recovered. For the above-mentioned n-butyl ether solution containing phenolic compounds, at 70°C and under negative pressure conditions, carry out distillation to recover n-butyl ether, and obtain the product phenolic compounds (rich in xylenol), which has a quality of 13.8g and consists of 2.9% phenol, 1.5% cresol, 95.2% xylenol, 0.4% neutral oil.

Claims (7)

1. a method for selective separation of phenolic mixtures in oil, characterized in that it may further comprise the steps: (1) According to the amount of quaternary ammonium salt added is 0.3 times -0.6 times the number of moles of phenol, add quaternary ammonium salt to the oil, at the separation temperature of 0°C-30°C, stir for 1min-30min, then let it stand for 1min -20min, the system is divided into two phases, the quaternary ammonium salt selectively forms a eutectic solvent with the phenol with strong force first, and the eutectic solvent is immiscible with the oil phase, so it is separated from the oil phase, and after separation, a phenol-rich Eutectic solvents and dephenolized oils; (2) The amount of quaternary ammonium salt added is 0.4-0.7 times the number of moles of cresol, add quaternary ammonium salt to the dephenolized oil in step (1), and stir for 1 min at the separation temperature of 0°C-30°C After -30min, let it stand for 1min-20min, the quaternary ammonium salt selectively forms a eutectic solvent with cresol, which is the second most active, and the eutectic solvent is immiscible with the oil phase and is separated from the oil phase. Eutectic solvents of phenols and dephenolized and cresolized oils; (3) The amount of quaternary ammonium salt added is 0.5-0.9 times the number of moles of xylenol, then add quaternary ammonium salt to the dephenolized oil in step (2), and stir at the separation temperature of 0°C-30°C After 1min-30min, stand still for 1min-20min, the quaternary ammonium salt selectively forms a eutectic solvent with xylenol, which has a smaller force, and the eutectic solvent is immiscible with the oil phase and is separated from the oil phase. After separation, Xylenol-enriched eutectic solvents and oils dephenolized, cresolized and xylenol-depleted; (4) After the above separation is completed, the three eutectic solvents are subjected to vacuum distillation at a pressure of 0.01 atm - 0.06 atm and a temperature of 60°C - 90°C to remove the neutral oil carried in them; (5) According to the volume ratio of anti-solvent and eutectic solvent of 4-7:1, add anti-solvent to the above three eutectic solvents for removing neutral oil respectively. Salt recrystallization is precipitated in solid form, filtered to realize the regeneration of quaternary ammonium salt, and three kinds of antisolvent solutions containing phenol are obtained; (6) Distill the three anti-solvent solutions containing phenol respectively, and separate the phenolic compound and the anti-solvent to obtain phenol, cresol, xylenol and anti-solvent respectively, and the anti-solvent is reused. 2. the method for the phenolic compound in a kind of selective separation oil as claimed in claim 1 is characterized in that described oil is the mixture of aromatic hydrocarbon, aliphatic hydrocarbon and phenolic compound, and wherein phenolic compound is phenol, cresol and Xylenol. 3. the method for a kind of selective separation of phenolic compounds in oil as claimed in claim 2, is characterized in that the concentration of phenolic compounds in oil is 50 g/L-300g/L. 4. the method for a kind of selective separation oil phenolic mixture as claimed in claim 1, is characterized in that described neutral oil is the mixture of aromatic hydrocarbon and aliphatic hydrocarbon. 5. the method for a kind of selective separation oil phenolic mixture as claimed in claim 1, is characterized in that described quaternary ammonium salt is choline chloride, tetramethyl ammonium chloride, tetraethyl ammonium chloride, Methyltriethylammonium chloride, tetraethylammonium bromide, or tetramethylammonium bromide. 6. the method for a kind of selective separation of phenolic mixture in oil as claimed in claim 1, is characterized in that the quaternary ammonium salt that step (1)-(3) adds is identical. 7. the method for a kind of selective separation of phenolic mixture in oil as claimed in claim 1 is characterized in that antisolvent is ether, isopropyl ether, n-butyl ether, ethyl acetate or methyl formate.