Purification method of beta-phenethyl alcohol

Abstract

The invention relates to the technical field of separation and purification processes, and discloses a purification method of beta-phenethyl alcohol. According to the purification method, a reaction mixture containing crude beta-phenethyl alcohol and metal halide is obtained, and the reaction mixture is stirred to react to obtain solid aromatic alkoxide; after the solid aromatic alkoxide is treated by a releasing agent, purified beta-phenethyl alcohol is obtained; the releasing agent is a solution comprising a protic solvent and at least one of an alkaline component and an ion exchange resin. According to the purification method disclosed by the invention, salifying crystallization and rectification are combined, peculiar smell components are removed from crude beta-phenethyl alcohol, purified beta-phenethyl alcohol with the purity of 99.5% or above is separated, tar smell is avoided, and the aroma of beta-phenethyl alcohol cannot be influenced; and the purification method is simple in process, low in production cost and suitable for industrial popularization.

Description

Technical Field

[0001] This invention relates to the technical field of separation and purification processes, and particularly to a method for purifying β-phenylethanol. Background Technology

[0002] β-Phenylacetyl alcohol, an aromatic alcohol with a rose-like scent, is an important flavoring agent widely used in food, tobacco, cosmetics, and other daily chemical products. β-Phenylacetyl alcohol has a high octane rating, calorific value, and energy density, and can be added to gasoline to improve its anti-knock properties. β-Phenylacetyl alcohol also acts as a bacterial inhibitor, exhibiting good antibacterial activity against Gram-negative bacteria, Escherichia coli, and Rhizoctonia solani (a member of the Solanaceae family).

[0003] Existing petroleum production processes produce petroleum tar, which contains dozens of components such as β-phenylethanol, ethylphenol, and phenylpropanol. Physical separation methods are generally used for separation. However, unlike synthetically produced β-phenylethanol, petroleum tar has a complex composition, and physical separation cannot completely remove the tar odor, which severely affects the aroma of β-phenylethanol. Several separation processes have been disclosed in existing technologies:

[0004] Firstly, patent CN 117088756 A discloses a method for recovering β-phenylethanol from heavy oil in styrene production processes, including distillation to remove heavy loads, reaction to remove phenols, and distillation of a side stream to obtain the β-phenylethanol product. This method uses a combination of conventional reaction and distillation processes to purify β-phenylethanol; however, it cannot effectively remove trace amounts of off-odor impurities.

[0005] Secondly, patent CN1170797C discloses a method for purifying β-phenylethanol. The crude β-phenylethanol is purified by extractive distillation using an extraction solvent system to remove odorous components and obtain a fragrant, high-purity β-phenylethanol suitable for use in fragrances.

[0006] Thirdly, patent CN101583584B discloses a purification method for β-phenylethanol. β-phenylethanol is obtained through a heavy separation step, an alkaline washing step, and a light boiling separation step (extractive distillation). Both of these methods employ extractive distillation combined with conventional separation operations in the field to purify β-phenylethanol. The introduction of an extractant system and the added step of extractant recovery increase the process cost and complexity.

[0007] Because petroleum tar contains various impurities, some of which also contain aromatic rings and hydroxyl groups, similar in structure to β-phenylethanol, this structural similarity leads to similar properties, increasing the complexity and difficulty of separating β-phenylethanol. Consequently, the tar odor cannot be completely removed, severely affecting the aroma of β-phenylethanol. Summary of the Invention

[0008] This invention addresses the problem that existing separation and purification methods for petroleum tar, which contain various impurities, cannot completely remove the tar odor, thus affecting the aroma of β-phenylethanol. This invention provides a purification method for β-phenylethanol that is simple, low-cost, and achieves a high rate of odor and impurity removal, making it suitable for industrial application.

[0009] The crude β-phenylethanol in this invention can be obtained from a byproduct of the propylene oxide / styrene production process through conventional distillation. The conventional distillation process refers to the process operation used to enrich β-phenylethanol, which generally involves passing the raw material through a packed tower or plate tower and then undergoing a process to remove light or heavy components.

[0010] The objective of this invention is to provide a method for purifying β-phenylethanol, obtaining a reaction mixture comprising crude β-phenylethanol and a metal halide, wherein the reaction mixture is stirred to obtain a solid aromatic alkoxide; the solid aromatic alkoxide is then treated with a releasing agent to obtain purified β-phenylethanol.

[0011] The releasing agent includes a proton solvent and an alkaline component and / or an ion exchange resin dispersed in the proton solvent.

[0012] The inventors discovered that reacting crude β-phenylethanol with metal halides can transform a solid-liquid mixture I (crude β-phenylethanol and metal halides) into a solid-liquid mixture II (solid aromatic alkoxide and solvent). In this system, the metal halides can selectively combine with β-phenylethanol to form crystalline aromatic alkoxides. Using a releasing agent containing a basic component or an ion exchange resin can effectively improve the recovery rate of β-phenylethanol, reduce product impurities, and obtain high-purity β-phenylethanol.

[0013] In one embodiment, the molar ratio of crude β-phenylethanol to metal halide is 1:(0.1-2), preferably 1:(0.4-1.4), and more preferably 1:(0.4-0.9). Specifically, the molar ratio of crude β-phenylethanol to metal halide is 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, or 1:2. A low content of metal halide will reduce the yield, while a high content will result in ineffective removal of odor molecules due to reaction with impurities. The molar ratio of crude β-phenylethanol to metal halide of the present invention is 1:(0.1-2), especially 1:(0.4-0.9, which can achieve both high yield and high purity.

[0014] Preferably, the metal halide includes at least one of metal fluoride, metal chloride, metal bromide and metal iodide; more preferably, it is a metal bromide or metal chloride.

[0015] In one embodiment, the metal halide includes at least one of alkaline earth metal halides and transition metal halides;

[0016] Preferably, the alkaline earth metal halide includes at least one of beryllium halide, magnesium halide, calcium halide and strontium halide; more preferably magnesium halide and / or calcium halide.

[0017] Preferably, the transition metal halide includes at least one of manganese halide, iron halide, ferrous halide, cobalt halide, nickel halide, copper halide, zinc halide, silver halide, and zirconium halide; more preferably, it includes at least one of manganese halide, zinc halide, and copper halide.

[0018] In one embodiment, the metal halide is manganese halide, preferably manganese chloride or manganese bromide, more preferably manganese bromide.

[0019] The crude β-phenylethanol of this invention is an aromatic hydrocarbon mixture with a boiling point of 140-250℃, comprising β-phenylethanol, phenylpropanol, benzyl alcohol, α-phenylethanol, acetophenone, phenols, and impurities. Phenylephrine includes at least one of 2-phenyl-1-propanol, 1-phenyl-2-propanol, 2-phenyl-2-propanol, 1-phenyl-1-propanol, and 3-phenyl-1-propanol; phenols include at least one of 2-ethylphenol, 3-ethylphenol, 4-ethylphenol, benzoic acid, and phenylacetic acid; impurities include at least one of styrene, benzaldehyde, and phenylacetaldehyde.

[0020] Although other hydroxyl alcohols and phenols in crude β-phenylethanol can also combine with metal halides to form salts, the inventors discovered that using manganese halides can improve the binding priority of metal halides to β-phenylethanol. Manganese halides exhibit the best selectivity for β-phenylethanol, especially manganese bromide. Manganese bromide shows the best selectivity for β-phenylethanol in crude β-phenylethanol, effectively improving the recovery rate.

[0021] Preferably, the metal halide is a powdered solid. Compared to a blocky solid, a powdered form can achieve a higher recovery rate.

[0022] In one embodiment, the temperature of the stirring reaction is 20°C-60°C, preferably 30°C-45°C; and / or, the stirring reaction time is 1-20 hours, preferably 5-12 hours. Specifically, the temperature is set to 20°C, 25°C, 25°C, 30°C, 32°C, 34°C, 36°C, 38°C, 40°C, 42°C, 45°C, 50°C, 55°C, or 60°C. The stirring reaction is carried out at 20°C-60°C for 1-20 hours. Under these conditions, impurity components are thoroughly removed, and the recovery rate of β-phenylethanol is high. Higher temperatures will have varying degrees of impact. Temperatures above 80°C will lead to the loss of diluent, making the solution unstable; temperatures above 100°C will lead to product loss; and temperatures above 120°C will cause side reactions of the raw materials, making it impossible to remove impurities.

[0023] Preferably, the crude β-phenylethanol is derived from a byproduct of the propylene oxide / styrene production process.

[0024] Preferably, the crude β-phenylethanol contains 20-99 wt% β-phenylethanol.

[0025] In one embodiment, a reaction mixture comprising crude β-phenylethanol and a metal halide is obtained by the following steps: the crude β-phenylethanol is first diluted with a diluent and then mixed with the metal halide;

[0026] Preferably, the mass ratio of the crude β-phenylethanol to the diluent is (1-6):1;

[0027] And / or, the diluent includes a nonpolar solvent and an alcohol; more preferably, the nonpolar solvent includes at least one of toluene, ethylbenzene, xylene, n-hexane and n-heptane; and / or, the alcohol includes at least one of methanol, ethanol and propanol.

[0028] Preferably, the alcohol content is 0.01-2 wt% of the total mass of the diluent, more preferably 0.3-0.5 wt%. Specifically, the alcohol content is 0.01 wt%, 0.05 wt%, 0.09 wt%, 0.1 wt%, 0.15 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.45 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, 1.1 wt%, 1.2 wt%, 1.3 wt%, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.7 wt%, 1.8 wt%, 1.9 wt%, or 2 wt% of the total mass of the diluent. The amount of alcohol in this invention can catalyze the reaction of β-phenylethanol in crude β-phenylethanol with metal halides. Under the same reaction conditions, using the amount of alcohol in this invention can effectively improve the recovery rate of β-phenylethanol.

[0029] In one embodiment, the proton solvent includes at least one of water and an alcohol solvent; preferably, the alcohol solvent includes at least one of methanol and ethanol; and the propanol is n-propanol and / or isopropanol.

[0030] And / or, the alkaline component includes at least one of sodium hydroxide, potassium hydroxide, calcium hydroxide and magnesium hydroxide;

[0031] And / or, the ion exchange resin is selected from anion exchange resin and / or cation exchange resin; preferably, the anion exchange resin is selected from a strongly basic anion exchange resin or a weakly basic anion exchange resin; and / or, the cation exchange resin is selected from a strongly acidic cation exchange resin or a weakly acidic cation exchange resin; and / or, the framework of the ion exchange resin is selected from macroporous resin or gel-type resin.

[0032] Preferably, the content of the alkaline component is 6-20 wt% of the total mass of the releasing agent;

[0033] Preferably, the amount of ion exchange resin loaded is 6-20 wt% of the daily production capacity of β-phenylethanol.

[0034] In one embodiment, after the stirring reaction, a solid-liquid separation process is performed to obtain a solid aromatic alkoxide;

[0035] And / or, the purified β-phenylethanol is obtained through the following steps: the solid aromatic alkoxide is treated with a releasing agent to obtain a mixture of at least two phases, which is then separated to obtain a liquid phase component containing β-phenylethanol, and then purified through a refining process to obtain purified β-phenylethanol; preferably, the refining process is distillation.

[0036] The separation process is a solid-liquid separation, preferably at least one of gravity filtration, pressure filtration, vacuum filtration, centrifugal filtration, and membrane filtration.

[0037] After solid-liquid separation, the solid and liquid components are different. The solid component contains more than 90% wt of β-phenylethanol, less than 2% wt of phenylpropanol, less than 1% wt of benzyl alcohol, less than 2% wt of α-phenylethanol, less than 0.1% wt of acetophenone, less than 2% wt of phenols, and less than 0.3% wt of impurities. Impurities include styrene, benzaldehyde, and phenylacetaldehyde.

[0038] The liquid component contains less than 5% wt of β-phenylethanol, more than 25% wt of phenylpropanol, more than 3% wt of benzyl alcohol, more than 10% wt of α-phenylethanol, more than 2% wt of acetophenone, more than 15% wt of phenols, and more than 5% wt of impurities. Impurities include styrene, benzaldehyde, phenylacetaldehyde, and other components.

[0039] The released metal halides and phenols are removed through conventional liquid-liquid separation. β-Phenylephethanol remains in another phase and proceeds to the purification process. For example, the metal halides and phenols dissolve in the aqueous phase, while β-Phenylephethanol remains in the organic phase.

[0040] In one embodiment, the mass ratio of the releasing agent to the solid aromatic alkoxide is 0.2-2:1, preferably 0.3-1:1.

[0041] In one embodiment, the reaction mixture does not contain protic acids, and preferably does not contain water.

[0042] In one embodiment, the distillation is carried out in a distillation column, the operating conditions of which include: a top temperature of 60-140°C, a bottom temperature of 90-170°C, a top pressure of 0.1-10 kPa, a bottom pressure of 0.5-15 kPa, a theoretical number of trays of 65-90, a feed number of trays of 5-20, a side-stream collection number of trays of 40-60, and a reflux ratio of 5-60.

[0043] Preferably, the operating conditions include: a top temperature of 60-85°C, and / or a bottom temperature of 90-110°C, and / or a top pressure of 0.1-0.5 kPa, and / or a bottom pressure of 0.5-1.5 kPa, and / or a theoretical number of trays of 70-85, and / or a feed number of 6-12, and / or a side-stream draw-out number of 50-60, and / or a reflux ratio of 15-50.

[0044] The top component includes small amounts of β-phenylethanol, phenylpropanol, benzyl alcohol, α-phenylethanol, acetophenone, releasing agent, diluent, and some remaining impurities; the side stream component is high-purity β-phenylethanol; the bottom component includes small amounts of β-phenylethanol, phenylpropanol, and some remaining impurities.

[0045] The purification system for β-phenylethanol used to implement the above purification method includes a mixing reactor, a crystallizer, a separator, and a distillation column connected in sequence.

[0046] The mixing reactor is used for diluting crude β-phenylethanol with a diluent;

[0047] The crystallizer is used to mix diluted crude β-phenylethanol with metal halides under a set temperature to produce solid aromatic alkoxides.

[0048] The separator is used to react solid aromatic alkoxides with the releasing agent and to separate mixtures that form at least two phases.

[0049] The distillation column is used for the distillation of liquid components containing β-phenylethanol.

[0050] The crude β-phenylethanol is diluted with a diluent in a mixing reactor; the crude β-phenylethanol is reacted with a metal halide in a crystallizer; and / or, the mixing is carried out with stirring at a set temperature in a crystallizer; and / or, the separation process is carried out in a separator; and / or, the distillation process is carried out in a distillation column.

[0051] Preferably, the purification process for crude β-phenylethanol includes a mixing reactor, a crystallizer, a separator, and a distillation column connected in sequence; after the above purification method, purified β-phenylethanol is output.

[0052] Mixed reactor: Crude β-phenylethanol is diluted with a diluent in a mixed reactor;

[0053] Crystallization separator: The diluted crude β-phenylethanol and powdered metal halide enter the crystallization separator, and the reaction produces solid aromatic alkoxides;

[0054] Separator: The solid aromatic alkoxide generated in the reaction is sent to the separator. A releasing agent is added to the separator. The solid aromatic alkoxide reacts with the releasing agent to form a mixture of at least two phases (depending on the choice of the releasing liquid, most are two-phase mixtures). The phase containing the released β-phenylethanol is separated. The separated liquid of other phases is discharged from the separator, and the separated solution of the phase containing β-phenylethanol enters the distillation column.

[0055] Distillation column: Purified β-phenylethanol is obtained through distillation separation.

[0056] For example, crude β-phenylethanol is diluted with a diluent (99.8 wt% toluene and 0.2 wt% ethanol), and powdered manganese chloride is added. After the reaction, β-phenylethanol manganese solid precipitate is generated. The separated β-phenylethanol manganese solid precipitate is added with a releasing agent (a mixture of 80 wt% water, 5 wt% ethanol, and 15 wt% sodium hydroxide). After β-phenylethanol is completely released, a two-phase mixture of a lower aqueous phase and an upper oil phase is formed. The upper oil phase is separated and then subjected to distillation.

[0057] The beneficial effects of the present invention are as follows: (1) The metal halide of the present invention can selectively combine with β-phenylethanol in crude β-phenylethanol to generate crystalline salts of aromatic alcohols. Using a releasing agent containing alkaline components or ion exchange resin can effectively improve the recovery rate of β-phenylethanol, reduce product impurities, and achieve high-purity purification of β-phenylethanol.

[0058] (2) The present invention combines crystallization and distillation to remove off-odor components from crude β-phenylethanol and separate purified β-phenylethanol with a purity of over 99.5%, which has no tar odor, does not affect the aroma of β-phenylethanol, and has a high yield.

[0059] (3) The purification method of β-phenylethanol provided in this invention is simple, has low production cost, and is suitable for industrial promotion. Attached Figure Description

[0060] Figure 1 This is a purification process flow diagram applicable to the purification method of β-phenylethanol of the present invention.

[0061] 1-Mixing reactor, 2-Crystallization separator, 3-Liquid separator, 4-Distillation column. Detailed Implementation

[0062] The present invention will be further described below with reference to specific embodiments, but this does not constitute any limitation on the present invention.

[0063] The crude β-phenylethanol in the following examples is a byproduct of the propylene oxide / styrene production process that has been subjected to conventional distillation to obtain a product with a boiling point of 180-230℃. The product contains 60 wt% β-phenylethanol, 8 wt% phenylpropanol (1-phenyl-2-propanol to 2-phenyl-1-propanol mass ratio of 9:7), 1 wt% benzyl alcohol, 2 wt% α-phenylethanol, 1 wt% acetophenone, 10 wt% phenols, and 18 wt% impurities.

[0064] like Figure 1 As shown, the purification process of β-phenylethanol of the present invention includes a mixing reactor 1, a crystallizer 2, a separator 3, and a distillation column 4; the mixing reactor 1, the crystallizer 2, the separator 3, and the distillation column 4 are connected in sequence by pipelines.

[0065] Crude β-phenylethanol S1 was diluted with diluent S2 in mixing reactor 1;

[0066] The diluted crude β-phenylethanol S3 and the metal halide are fed into crystallizer 2 and stirred and mixed at 20℃-60℃ for 1-20h. The solid aromatic alkoxide S4 generated by the reaction is separated by crystallizer 2 to obtain solid aromatic alkoxide S4.

[0067] Solid aromatic alkoxide S4 is sent to separator 3, and a releasing agent is added to separator 3. Solid aromatic alkoxide S4 reacts with the releasing agent to form a mixture of at least two phases (depending on the choice of the releasing liquid, most are two-phase mixtures). The phase containing β-phenylethanol after release is separated, and the separated liquid S5 of other phases is discharged from separator 3. The separated solution S6 containing β-phenylethanol enters distillation column 4.

[0068] The purified β-phenylethanol was obtained by distillation.

[0069]

Example 1

[0070] First, 200 kg of crude β-phenylethanol, 3 times its mass (600 kg) of diluent toluene, and 2.8 kg of n-propanol were mixed thoroughly to form mixture I. Mixture I was then mixed thoroughly with 106 kg of manganese bromide powder (particle size 50 μm, molar ratio of crude β-phenylethanol to manganese bromide powder 1:0.5) to obtain solid-liquid mixture I. Solid-liquid mixture I was stirred thoroughly at 40 °C for 8 h to obtain solid-liquid mixture II. Solid-liquid mixture II was separated into solid and liquid phases by pressure filtration to obtain solid aromatic manganese alcohol 22. 0 kg; 130 kg of a 15 wt% sodium hydroxide-ethanol-water solution (containing 80 wt% water, 5 wt% ethanol, and 15 wt% sodium hydroxide) was added to the aromatic alkoxide solid to obtain mixture II; the upper layer of mixture II was then subjected to distillation under the following conditions: top temperature 60℃, bottom temperature 90℃, top pressure 0.1 kPa, bottom pressure 0.5 kPa, theoretical plate number 85, feed plate number 12, side stream plate number 50, and reflux ratio 50. Finally, 110 kg of high-purity β-phenylethanol was obtained.

[0071]

Example 2

[0072] The difference from Example 1 is that the dilution ratio (mass ratio of toluene to crude β-phenylethanol) is 6:1, that is, 1200 kg of toluene is used as the diluent. The final product yielded 108 kg of high-purity β-phenylethanol.

[0073]

Example 3

[0074] The difference from Example 1 is that the molar ratio of crude β-phenylethanol to manganese bromide powder is changed from 1:0.5 to 1:0.3. That is, the mixture I is mixed evenly with 63.6 kg of manganese bromide powder to obtain solid-liquid mixture I. Finally, 95 kg of high-purity β-phenylethanol product is obtained.

[0075]

Example 4

[0076] The difference from Example 1 is that the molar ratio of crude β-phenylethanol to manganese bromide powder is changed from 1:0.5 to 1:1.5. That is, the mixture I is mixed evenly with 318 kg of manganese bromide powder to obtain solid-liquid mixture I. Finally, 118 kg of high-purity β-phenylethanol product is obtained.

[0077]

Example 5

[0078] The difference from Example 1 is that the molar ratio of β-phenylethanol to manganese bromide powder is changed from 1:0.5 to 1:1, that is, the mixture I is mixed evenly with 212 kg of manganese bromide powder to obtain solid-liquid mixture I. 116 kg of high-purity β-phenylethanol product is obtained.

[0079]

Example 6

[0080] The difference from Example 1 is that the manganese bromide metal halide powder was replaced with copper bromide powder. 102 kg of high-purity β-phenylethanol was obtained.

[0081]

Example 7

[0082] The difference from Example 1 is that the manganese bromide metal halide powder was replaced with manganese chloride powder. 107 kg of high-purity β-phenylethanol was obtained.

[0083]

Example 8

[0084] The difference from Example 1 is that the manganese bromide metal halide powder was replaced with calcium chloride powder. 108 kg of high-purity β-phenylethanol was obtained.

[0085]

Example 9

[0086] The difference from Example 1 is that the manganese bromide metal halide powder was replaced with zinc chloride powder. 106 kg of high-purity β-phenylethanol was obtained.

[0087]

Example 10

[0088] The difference from Example 1 is that no alcohol is added to the diluent; that is, the diluent is entirely toluene. 101 kg of high-purity β-phenylethanol was obtained.

[0089]

Example 11

[0090] The difference from Example 1 is that the releasing agent was replaced with a 15wt% sodium hydroxide aqueous solution. 109 kg of high-purity β-phenylethanol product was obtained.

[0091]

Example 12

[0092] The difference from Example 1 is that the releasing agent is a 15wt% sodium hydroxide ethanol solution. 111 kg of high-purity β-phenylethanol product was obtained.

[0093]

Example 13

[0094] The difference from Example 1 is that the releasing agent is a 2wt% sodium hydroxide ethanol aqueous solution (containing 90wt% water, 8wt% ethanol and 2wt% sodium hydroxide). 106 kg of high-purity β-phenylethanol product was obtained.

[0095]

Example 14

[0096] The difference from Example 1 is that the manganese bromide powder was replaced with blocky manganese bromide with a particle size of 3 mm. 100 kg of high-purity β-phenylethanol was obtained.

[0097]

Example 15

[0098] The difference from Example 1 is that the distillation operating conditions included: a column top temperature of 50°C, a column bottom temperature of 80°C, a column top pressure of 0.1 kPa, a column bottom pressure of 0.4 kPa, a theoretical number of plates of 88, a feed number of plates of 5, a side stream collection number of 50, and a reflux ratio of 55. 112 kg of high-purity β-phenylethanol was obtained.

[0099]

Example 16

[0100] The difference from Example 1 is that the reaction temperature in step "stirring the solid-liquid mixture I at 40°C for 8 hours to obtain solid-liquid mixture II" is changed to 70°C. 108 kg of high-purity β-phenylethanol product was obtained.

[0101]

Example 17

[0102] The difference from Example 1 is that the "15 wt% sodium hydroxide" in the releasing agent "15% sodium hydroxide-ethanol-water solution (containing 80 wt% water, 5 wt% ethanol and 15 wt% sodium hydroxide)" is replaced with "a strongly basic anion exchange resin column (containing 80 wt% water, 5 wt% ethanol and 15 wt% strongly basic anion exchange resin) with a packing weight equal to the daily production of β-phenylethanol" and adsorption and elution are performed. 110 kg of high-purity β-phenylethanol product was obtained.

[0103]

Example 18

[0104] The difference from Example 8 is that calcium chloride was replaced with copper chloride dihydrate in the same molar ratio. 70 kg of high-purity β-phenylethanol was obtained.

[0105]

Example 19

[0106] The difference from Example 1 is that the 2.8 kg of n-propanol in Mixture I was replaced with 2 kg of n-propanol. 110 kg of high-purity β-phenylethanol product was obtained.

[0107]

Comparative Example 1

[0108] The difference from Example 1 is that manganese bromide was replaced with manganese oxide in the same molar ratio. 48 kg of high-purity β-phenylethanol was obtained.

[0109] [Comparative Example 2]

[0110] The difference from Example 1 is that β-phenylethanol in the raw material components is replaced with α-phenylethanol: that is, the raw material components are 62wt% α-phenylethanol, 8wt% phenylpropanol, 1wt% benzyl alcohol, 1wt% acetophenone, 10wt% phenols, and 18wt% impurities.

[0111] [Comparative Example 3]

[0112] The difference from Example 1 is that the releasing agent is an aqueous ethanol solution (containing 95 wt% water and 5 wt% ethanol), that is, it contains only water and ethanol and does not contain sodium hydroxide. 65 kg of high-purity β-phenylethanol product was obtained.

[0113] [Comparative Example 4]

[0114] The difference from Example 1 is that it does not contain the step of "stirring the solid-liquid mixture I at 40°C for 8 hours to obtain solid-liquid mixture II".

[0115] First, 200 kg of crude β-phenylethanol, 3 times its mass (600 kg) of diluent toluene, and 2.8 kg of n-propanol are mixed evenly to form mixture I. Mixture I is then mixed evenly with 106 kg of manganese bromide powder (the molar ratio of crude β-phenylethanol to manganese bromide powder is 1:0.5) to obtain solid-liquid mixture I. Solid-liquid mixture I is then separated by pressure filtration to obtain 100 kg of solid. A 15% concentration of releasing agent is added to the aromatic solid. 130 kg of a sodium hydroxide-ethanol-water solution (containing 80 wt% water, 5 wt% ethanol, and 15 wt% sodium hydroxide) was prepared to obtain mixture II. The upper layer of mixture II was then subjected to rectification distillation under the following conditions: top temperature 60°C, bottom temperature 90°C, top pressure 0.1 kPa, bottom pressure 0.5 kPa, theoretical plate number 85, feed plate number 12, side stream plate number 50, and reflux ratio 50. The final product was 0 kg of high-purity β-phenylethanol.

[0116] The crude β-phenylethanol raw material was compared with the purified β-phenylethanol obtained in Examples 1-19 and Comparative Examples 1-4 for component determination using GC-FID. The results are shown in Table 1 below.

[0117] The recovery rate (%) is calculated as follows: (Product β-phenylethanol content * Product mass) / (Raw material β-phenylethanol content * Raw material mass).

[0118] Table 1

[0119]

[0120] As shown in the table above, the preferred embodiment of the separation and purification method of the present invention can effectively remove the tar odor, ensuring that the aroma of β-phenylethanol is not affected. The tar odor is mainly due to components such as phenylpropanol and phenols. After treatment by the purification method of the present invention, the purified β-phenylethanol has essentially had impurities such as phenylpropanol and phenols removed.

[0121] As shown in Examples 1 and 3-5, the molar ratio of β-phenylethanol to metal halide is 0.3-1.5, preferably 1:0.4-0.9. Too high a ratio will increase costs and impurities; too low a ratio will reduce the recovery rate.

[0122] As shown in Examples 1 and 6-9, among the metal halides, manganese bromide has the best effect, while calcium halide and copper bromide are significantly less effective than manganese bromide; manganese chloride has a similar effect to manganese bromide.

[0123] Adding a catalyst amount of alcohol to the diluent can promote crystallization and accelerate the reaction, especially when the content is 0.3-0.5 wt%. Too high or too low a content will affect the salt crystallization effect.

[0124] The releasing agent reacts with aromatic alkoxides to regenerate β-phenylethanol and metal ions. The releasing agent and β-phenylethanol have significantly different polarities and are immiscible, resulting in stratified products. If the releasing agent is an aqueous solution of sodium hydroxide, β-phenylethanol resides in the upper oil phase, while impurities and metal ions dissolve in the lower aqueous layer. The two layers can be separated by liquid-liquid chromatography. The addition of sodium hydroxide has a decolorizing effect. The addition of alcohol to the releasing agent increases its solubility.

[0125] Compared to bulk metal halides, powdered metal halides are more effective in promoting the reaction and salt formation and crystallization.

[0126] The crude β-phenylethanol reacts with metal halides under protic acid-free conditions. Metal halides containing water of crystallization have a negative effect on promoting salt formation and crystallization. For example, in Example 18, simply replacing calcium oxide with an equimolar amount of copper chloride dihydrate resulted in a significant decrease in recovery rate.

[0127] Comparative Examples 1-4 show that metal chlorides are significantly more effective than metal oxides in purifying β-phenylethanol, while metal oxides cannot achieve the same result. The selectivity of metal halides for β-phenylethanol differs greatly from that for α-phenylethanol. The presence of a basic component in the releasing agent is essential; the absence of a basic substance will severely reduce the recovery rate of β-phenylethanol. Comparative Example 4 demonstrates that specific reaction conditions at a certain temperature are also crucial.

[0128] Any numerical value mentioned in this invention, if there is only a two-unit interval between any minimum and any maximum value, includes all values ​​that increase by one unit each time from the minimum to the maximum value. For example, if the amount of a component, or the value of a process variable such as temperature, pressure, or time, is stated as 50-90, in this specification it means specifically listing values ​​such as 51-89, 52-88, ..., 69-71, and 70-71, etc. For non-integer values, it may be appropriately considered that a unit is 0.1, 0.01, 0.001, or 0.0001. These are merely some specifically specified examples. In this invention, in a similar manner, all possible combinations of numerical values ​​between the listed minimum and maximum values ​​are considered to have been disclosed.

[0129] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A method for purifying β-phenylethanol, characterized in that: A reaction mixture comprising crude β-phenylethanol and a metal halide was obtained, and the reaction mixture was stirred to obtain a solid aromatic alkoxide; the solid aromatic alkoxide was treated with a releasing agent to obtain purified β-phenylethanol; The releasing agent includes a proton solvent and an alkaline component and / or an ion exchange resin dispersed in the proton solvent.

2. The purification method according to claim 1, characterized in that: Based on the amount of β-phenylethanol in the crude β-phenylethanol, the molar ratio of the crude β-phenylethanol to the metal halide is 1:(0.1-2), preferably 1:(0.4-1.4), and more preferably 1:(0.4-0.9); And / or, the metal halide includes at least one of metal fluoride, metal chloride, metal bromide and metal iodide; preferably a metal bromide or metal chloride.

3. The purification method according to claim 1 or 2, characterized in that: The metal halide includes at least one of alkaline earth metal halides and transition metal halides; Preferably, the alkaline earth metal halide includes at least one of beryllium halide, magnesium halide, calcium halide, and strontium halide; more preferably, magnesium halide and / or calcium halide; And / or, the transition metal halide includes at least one of manganese halide, iron halide, ferrous halide, cobalt halide, nickel halide, copper halide, zinc halide, silver halide and zirconium halide; preferably at least one of manganese halide, zinc halide and copper halide.

4. The purification method according to any one of claims 1-3, characterized in that: The temperature of the stirring reaction is 20℃-60℃, preferably 30℃-45℃; and / or the time of the stirring reaction is 1-20h, preferably 5-12h. And / or, the crude β-phenylethanol is derived from a byproduct of the propylene oxide / styrene production process; And / or, the crude β-phenylethanol content is 20-99 wt%.

5. The purification method according to any one of claims 1-4, characterized in that: A reaction mixture comprising crude β-phenylethanol and metal halides is obtained by the following steps: the crude β-phenylethanol is first diluted with a diluent and then mixed with the metal halides; Preferably, the mass ratio of the crude β-phenylethanol to the diluent is (1-6):1; And / or, the diluent includes a nonpolar solvent and an alcohol; more preferably, the nonpolar solvent includes at least one of toluene, ethylbenzene, xylene, n-hexane and n-heptane; and / or, the alcohol includes at least one of methanol, ethanol and propanol; and / or, the alcohol content is 0.01-2 wt% of the total mass of the diluent, preferably 0.3-0.5 wt%.

6. The purification method according to any one of claims 1-5, characterized in that: The proton solvent includes at least one of water and alcohol solvents; preferably, the alcohol solvent includes at least one of methanol and ethanol. And / or, the alkaline component includes at least one of sodium hydroxide, potassium hydroxide, calcium hydroxide and magnesium hydroxide; And / or, the ion exchange resin is selected from one of anion exchange resins and / or cation exchange resins; preferably, the anion exchange resin is selected from a strongly basic anion exchange resin or a weakly basic anion exchange resin; and / or, the cation exchange resin is selected from a strongly acidic cation exchange resin or a weakly acidic cation exchange resin. And / or, the content of the alkaline component is 6-20 wt% of the total mass of the releasing agent; And / or, the ion exchange resin is filled at a rate of 6-20 wt% of the daily production capacity of β-phenylethanol.

7. The purification method according to any one of claims 1-6, characterized in that: After stirring and reaction, solid-liquid separation is performed to obtain solid aromatic alkoxides; And / or, the purified β-phenylethanol is obtained through the following steps: the solid aromatic alkoxide is treated with a releasing agent to obtain a mixture of at least two phases, which is then separated to obtain a liquid phase component containing β-phenylethanol, and then purified through a refining process to obtain purified β-phenylethanol; preferably, the refining process is distillation.

8. The purification method according to any one of claims 1-7, characterized in that: The mass ratio of the releasing agent to the solid aromatic alkoxide is 0.2-2:1, preferably 0.3-1:

1.

9. The purification method according to claim 7, characterized in that: The distillation process is carried out in a distillation column, and the operating conditions of the distillation column include: a top temperature of 60-140℃, a bottom temperature of 90-170℃, a top pressure of 0.1-10 kPa, a bottom pressure of 0.5-15 kPa, a theoretical number of trays of 65-90, a feed number of trays of 5-20, a side-stream collection number of trays of 40-60, and a reflux ratio of 5-60.

10. The purification method according to claim 9, characterized in that: Operating conditions include: top temperature of 60-85℃, and / or bottom temperature of 90-110℃, and / or top pressure of 0.1-0.5 kPa, and / or bottom pressure of 0.5-1.5 kPa, and / or theoretical number of trays of 70-85, and / or feed number of trays of 6-12, and / or side-stream trays of 50-60, and / or reflux ratio of 15-50.

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