A process for the preparation of a bisphenol f epoxy resin

Abstract

The present application belongs to the technical field of bisphenol F epoxy resin, and particularly relates to a preparation method of bisphenol F epoxy resin. In a protective gas atmosphere, bisphenol F, epichlorohydrin and an inorganic strong alkali aqueous solution are mixed to perform etherification reaction to obtain a reaction liquid containing chlorohydrin ether; under negative pressure, the inorganic strong alkali aqueous solution is added dropwise to the reaction liquid containing chlorohydrin ether to perform ring closure reaction to obtain bisphenol F epoxy resin; the dropwise adding includes sequentially performing first stage dropwise adding, second stage dropwise adding and third stage dropwise adding. By adopting a two-step method, no solvent or additive is needed in the pre-reaction stage, the dropwise adding procedure of liquid alkali in the main reaction stage is controlled, the alkali utilization rate is effectively improved, the raw material consumption is reduced, the side reaction is reduced, the quality of bisphenol F epoxy resin is improved, the product has high epoxy value and low hydrolyzable chlorine, and the safe and green production level is reached.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of epoxy resin, and particularly relates to a preparation method of bisphenol F epoxy resin. BACKGROUND

[0002] The -CH2- group in the molecular structure of bisphenol F epoxy resin has greater rotatability than the CH3-C-CH3 group in the molecular structure of bisphenol A epoxy resin, and the room temperature viscosity is only 1 / 4 to 1 / 7 of that of bisphenol A epoxy resin. The bisphenol F epoxy resin reduces the viscosity and rigidity of bisphenol A epoxy resin and increases flexibility and flowability, and therefore has better application performance.

[0003] At present, the bisphenol F epoxy resin has excellent strength-to-weight ratio, high temperature resistance and corrosion resistance and the like, and is widely used in structural parts of wind turbine blades, aircraft, satellites and spacecraft and the like and solid rocket engine shells and the like. Therefore, it is of great significance to study the process development of bisphenol F epoxy resin.

[0004] The traditional synthesis process of bisphenol F epoxy resin is to add quaternary ammonium salt as a catalytic aid or to add an organic solvent as a promoter in the initial stage of the reaction, such as adding benzyl trimethyl ammonium chloride, tetramethyl ammonium chloride or adding solvents such as methanol, secondary alcohol, isopropyl alcohol, isobutyl alcohol and the like. The above-mentioned catalytic aid or promoter is used to assist the ring-opening reaction of alkali, so as to generate chloroether alcohol. However, the above-mentioned traditional synthesis process of bisphenol F epoxy resin is complicated, needs to use a catalytic aid or an organic solvent, leads to high solvent consumption and high energy consumption, needs to additionally increase equipment for separating and recovering the solvent and the catalytic aid, simultaneously increases the amount of three wastes, and leads to high production cost of bisphenol F epoxy resin. SUMMARY

[0005] The purpose of the present application is to provide a preparation method of bisphenol F epoxy resin. The method provided by the present application does not need to add an organic solvent or an aid in the reaction stage, simultaneously improves the utilization rate of alkali, reduces raw material consumption, reduces side reactions, improves the quality of bisphenol F epoxy resin, realizes high epoxy value and low hydrolyzable chlorine of the product, reaches the level of safe and green production, effectively reduces the production cost of bisphenol F epoxy resin, and is suitable for industrial production.

[0006] In order to achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0007] The present application provides a preparation method of bisphenol F epoxy resin, comprising the following steps:

[0008] In a protective gas atmosphere, bisphenol F, epichlorohydrin and a first inorganic strong alkali aqueous solution are mixed to perform etherification reaction, so as to obtain a reaction liquid containing chloroether.

[0009] Under the condition of negative pressure, a second inorganic strong alkali aqueous solution is added dropwise into the reaction solution containing chlorohydrin ether to perform a ring-closing reaction, so as to obtain a bisphenol F epoxy resin; the dropwise adding includes sequentially performing first stage dropwise adding, second stage dropwise adding and third stage dropwise adding, the time of the first stage dropwise adding, the time of the second stage dropwise adding and the time of the third stage dropwise adding respectively account for 1 / 3 of the total time, the mass percentage of the second inorganic strong alkali aqueous solution in the first stage dropwise adding in the total mass of the second inorganic strong alkali aqueous solution is 25-30%, the mass percentage of the second inorganic strong alkali aqueous solution in the second stage dropwise adding in the total mass of the second inorganic strong alkali aqueous solution is 30-32%, and the mass percentage of the second inorganic strong alkali aqueous solution in the third stage dropwise adding in the total mass of the second inorganic strong alkali aqueous solution is 38-45%; during the ring-closing reaction, azeotropic distillation is performed between the epichlorohydrin and water, so as to obtain azeotropic distillation product; the epichlorohydrin obtained after separating water from the azeotropic distillation product is refluxed to continue the ring-closing reaction.

[0010] Preferably, the second inorganic strong alkali aqueous solution is added dropwise to obtain a ring-closing reaction solution; then the ring-closing reaction solution is subjected to epichlorohydrin removal to obtain a bisphenol F epoxy resin crude reaction solution;

[0011] The bisphenol F epoxy resin crude reaction solution and a first organic solvent are mixed to obtain a mixed solution; a third inorganic strong alkali aqueous solution is added dropwise into the mixed solution to perform a refining reaction, so as to obtain a refined reaction solution;

[0012] The refined reaction solution and an extraction solvent are mixed and then allowed to stand to be separated into layers, so as to obtain an oil phase product; the extraction solvent is a second organic solvent or a second organic solvent and water;

[0013] The oil phase product is sequentially subjected to neutralization, water washing and desolvation, so as to obtain a refined product of the bisphenol F epoxy resin.

[0014] Preferably, the inorganic strong alkali in the first inorganic strong alkali aqueous solution includes sodium hydroxide and / or potassium hydroxide;

[0015] The mass percentage of the inorganic strong alkali in the first inorganic strong alkali aqueous solution is 32-50%;

[0016] The molar ratio of the inorganic strong alkali in the first inorganic strong alkali aqueous solution to the bisphenol F is 0.15-0.16:1.

[0017] Preferably, the molar ratio of the bisphenol F to the epichlorohydrin is 0.5:(2.5-4);

[0018] The protective gas is nitrogen, and the flow rate of the protective gas is 15-20 L / h.

[0019] Preferably, the conversion rate of bisphenol F in the etherification reaction is 87-94%.

[0020] Preferably, the temperature of the etherification reaction is 50-55℃, and the time is 2h.

[0021] Preferably, the temperature of the ring-closing reaction is 60-63℃, and the negative pressure condition of the ring-closing reaction is -78-80kPa.

[0022] Preferably, the inorganic strong base in the second inorganic strong base aqueous solution comprises sodium hydroxide and / or potassium hydroxide.

[0023] The mass percentage of the inorganic strong base in the second inorganic strong base aqueous solution is 45-50%.

[0024] The total time for dropping the second inorganic strong base aqueous solution is 3h.

[0025] The molar ratio of bisphenol F to the inorganic strong base in the second inorganic strong base aqueous solution is 0.5:(0.9-1).

[0026] Preferably, the first organic solvent and the second organic solvent comprise toluene or methyl isobutyl ketone.

[0027] The inorganic strong base in the third inorganic strong base aqueous solution comprises sodium hydroxide and / or potassium hydroxide.

[0028] The mass percentage of the inorganic strong base in the third inorganic strong base aqueous solution is 30-32%.

[0029] The molar ratio of the inorganic strong base in the third inorganic strong base aqueous solution to bisphenol F is (0.14-0.15):0.5.

[0030] Preferably, the temperature of the refining reaction is 80-90℃, the dropping time of the third inorganic strong base aqueous solution is 20-30min, and the holding reaction time of the refining reaction is 1-1.5h.

[0031] The application provides a preparation method of bisphenol F epoxy resin, comprising the following steps: mixing bisphenol F, epichlorohydrin and a first inorganic strong alkali aqueous solution in a protective gas atmosphere to perform etherification reaction, so as to obtain a reaction liquid containing chlorohydrin ether; under negative pressure, a second inorganic strong alkali aqueous solution is added dropwise into the reaction liquid containing chlorohydrin ether to perform ring closure reaction, so as to obtain bisphenol F epoxy resin; the dropwise adding comprises sequentially performing first stage dropwise adding, second stage dropwise adding and third stage dropwise adding, the time of the first stage dropwise adding, the time of the second stage dropwise adding and the time of the third stage dropwise adding respectively account for 1 / 3 of the total dropwise adding time, the mass percentage of the second inorganic strong alkali aqueous solution in the first stage dropwise adding in the total mass of the second inorganic strong alkali aqueous solution is 25-30%, the mass percentage of the second inorganic strong alkali aqueous solution in the second stage dropwise adding in the total mass of the second inorganic strong alkali aqueous solution is 30-32%, and the mass percentage of the second inorganic strong alkali aqueous solution in the third stage dropwise adding in the total mass of the second inorganic strong alkali aqueous solution is 38-45%; during the ring closure reaction, the epichlorohydrin and water are subjected to azeotropic distillation, so as to obtain azeotropic distillation products; the epichlorohydrin obtained after separating water from the azeotropic distillation products is refluxed to continue the ring closure reaction.In conclusion, the present application effectively improves the alkali utilization rate, reduces raw material consumption, reduces side reactions, improves the quality of bisphenol F epoxy resin, realizes high epoxy value and low hydrolyzable chlorine, and achieves safe and green production level by adopting a two-step method, without adding solvent or auxiliary agent in the pre-reaction stage and main reaction stage, and controlling the dropping procedure of liquid alkali in the main reaction stage.

[0032] Further, in the present application, the closed loop reaction liquid is obtained after the dropping is completed; after obtaining the closed loop reaction liquid, further comprising: removing the epichlorohydrin from the closed loop reaction liquid to obtain a bisphenol F epoxy resin crude reaction liquid; mixing the bisphenol F epoxy resin crude reaction liquid and the first organic solvent, and then dropping the third inorganic strong alkali aqueous solution for refining reaction to obtain a refined reaction liquid; mixing the refined reaction liquid, the second organic solvent and water, and then standing and separating to obtain an oil phase product; and sequentially performing neutralization, water washing and desolventizing on the oil phase product to obtain a refined product of bisphenol F epoxy resin. The present application removes the epichlorohydrin (ECH) and then performs refining reaction, which can make the reaction more sufficient, reduce the hydrolyzable chlorine content in the resin product, and obtain a bisphenol F epoxy resin product meeting the industrial quality standard.

[0033] Further, in the present application, the inorganic strong base in the first inorganic strong alkali aqueous solution comprises sodium hydroxide and / or potassium hydroxide; the mass percentage content of the inorganic strong base in the first inorganic strong alkali aqueous solution is 32-50%; and the molar ratio of the inorganic strong base in the first inorganic strong alkali aqueous solution to the bisphenol F is 0.15-0.16:1. The present application optimizes the amount of inorganic strong base (the inorganic strong base in the first inorganic strong alkali aqueous solution, i.e. the catalyst) in the pre-reaction stage, controls the conversion rate of bisphenol F to be 87-94%, and reduces side reactions by controlling the conversion rate of bisphenol F in the pre-reaction stage to be 87-94%. The pre-reaction and the main reaction stages are difficult to be completely separated, and the etherification reaction (ring-opening reaction) also occurs in the main reaction stage. When the alkali amount in the pre-reaction stage is too small, the conversion rate of bisphenol F is low, and the reaction yield is low; when the alkali amount in the pre-reaction stage is too large, a large amount of ECH in the system will hydrolyze with water at the initial stage of the reaction, which increases raw material consumption and by-product formation.

[0034] Further, in the present application, the temperature of the closed loop reaction is 60-63℃. The closed loop reaction in the present application is an endothermic reaction, and the reaction effect is poor when the temperature is too low; when the temperature is too high, side reactions increase, such as the hydrolysis reaction of epoxy groups, branching reaction, abnormal addition reaction of phenolic hydroxyl groups and epoxy groups, and side reactions of molecular chain growth, etc., which finally leads to that the average molecular weight of the bisphenol F epoxy resin product is large, the epoxy equivalent is high, and the viscosity is high.

[0035] Further, in the present application, the mass percentage content of inorganic strong base in the first inorganic strong base aqueous solution is preferably 32-50%. The mass percentage content of inorganic strong base in the second inorganic strong base aqueous solution is preferably 45-50%. The present application controls the mass concentration of inorganic strong base aqueous solution used in the ring-opening reaction and the ring-closing reaction, thereby controlling the water content in the ring-opening reaction and the ring-closing reaction system. Too much water in the reaction system promotes the hydrolysis reaction of epichlorohydrin under alkaline conditions, generating glycerol, which further adds to the generated epoxy resin, thereby deteriorating the product quality.

[0036] In summary, the present application provides a preparation method of bisphenol F epoxy resin, which is efficient, easy to operate and control, and mild in conditions. In the reaction process, inorganic strong base is used without the use of quaternary ammonium salt and other additives. The treated wastewater (water phase obtained by standing and layering of refined reaction liquid) can be recycled to electrolysis, which is green, low-carbon, and low-emission. The main reaction adopts a negative pressure segmented liquid alkali process, which effectively improves the alkali utilization rate, reduces the raw material consumption, reduces the side reaction, improves the product performance of the epoxy resin, and is suitable for industrial production. DETAILED DESCRIPTION

[0037] The present application provides a preparation method of bisphenol F epoxy resin, which comprises the following steps:

[0038] In a protective gas atmosphere, bisphenol F, epichlorohydrin and a first inorganic strong base aqueous solution are mixed to perform etherification reaction, to obtain a reaction liquid containing chlorohydrin ether;

[0039] Under negative pressure, a second inorganic strong base aqueous solution is added dropwise to the reaction liquid containing chlorohydrin ether to perform ring-closing reaction, to obtain bisphenol F epoxy resin. The dropwise adding includes sequentially performing first stage dropwise adding, second stage dropwise adding and third stage dropwise adding. The time of the first stage dropwise adding, the time of the second stage dropwise adding and the time of the third stage dropwise adding respectively account for 1 / 3 of the total dropwise adding time. The mass percentage of the second inorganic strong base aqueous solution used in the first stage dropwise adding in the total mass of the second inorganic strong base aqueous solution is 25-30%. The mass percentage of the second inorganic strong base aqueous solution used in the second stage dropwise adding in the total mass of the second inorganic strong base aqueous solution is 30-32%. The mass percentage of the second inorganic strong base aqueous solution used in the third stage dropwise adding in the total mass of the second inorganic strong base aqueous solution is 38-45%. In the ring-closing reaction process, epichlorohydrin and water are subjected to azeotropic distillation to obtain azeotropic distillation product. The epichlorohydrin obtained by separating water from the azeotropic distillation product is refluxed to continue the ring-closing reaction.

[0040] In the present application, all the preparation raw materials / components are commercially available products well known to those skilled in the art, unless otherwise specified.

[0041] The preparation method provided by the present application does not use auxiliary agents and organic solvents.

[0042] In the present application, the bisphenol F is mixed with epichlorohydrin and a first inorganic strong base aqueous solution in a protective gas atmosphere to perform etherification reaction to obtain a reaction liquid containing chlorohydrin ether. In the present application, the purity of the bisphenol F is preferably ≥ 90%. The purity of the epichlorohydrin is preferably ≥ 99.9%. The inorganic strong base in the first inorganic strong base aqueous solution preferably includes sodium hydroxide and / or potassium hydroxide, and in the examples, it is specifically sodium hydroxide. The mass percentage of the inorganic strong base in the first inorganic strong base aqueous solution is preferably 32-50%. The molar ratio of the inorganic strong base in the first inorganic strong base aqueous solution to the bisphenol F is preferably 0.15-0.16:1, and specifically preferably 0.16:1, 0.15:1. The molar ratio of the bisphenol F to the epichlorohydrin is preferably 0.5:(2.5-4), and specifically preferably 0.5:4, 0.5:2.5. The protective gas is preferably nitrogen, and the flow rate of the protective gas is preferably 15-20 L / h, and specifically preferably 15 L / h, 20 L / h. The temperature of the etherification reaction is preferably 50-55℃, and specifically preferably 50℃, 55℃. The time of the etherification reaction is preferably 2 h. The etherification reaction generates chlorohydrin ether, and the conversion rate of the bisphenol F in the etherification reaction is preferably 87-94%.

[0043] In the present application, after obtaining the reaction liquid containing chlorohydrin ether, the protective gas is preferably turned off to perform the following ring-closing reaction.

[0044] After obtaining the reaction liquid containing chlorohydrin ether, the present application performs ring-closing reaction by adding a second inorganic strong base aqueous solution to the reaction liquid containing chlorohydrin ether under negative pressure to obtain a bisphenol F epoxy resin; the adding includes sequentially performing first-stage adding, second-stage adding and third-stage adding, and the time of the first-stage adding, the time of the second-stage adding and the time of the third-stage adding respectively account for 1 / 3 of the total adding time, the mass percentage of the second inorganic strong base aqueous solution in the first-stage adding to the total mass of the second inorganic strong base aqueous solution is 25-30%, the mass percentage of the second inorganic strong base aqueous solution in the second-stage adding to the total mass of the second inorganic strong base aqueous solution is 30-32%, and the mass percentage of the second inorganic strong base aqueous solution in the third-stage adding to the total mass of the second inorganic strong base aqueous solution is 38-45%; during the ring-closing reaction, the epichlorohydrin and water perform azeotropic distillation to obtain azeotropic distillation products; and the epichlorohydrin obtained by separating water from the azeotropic distillation products is refluxed to continue the ring-closing reaction.

[0045] In the present application, the inorganic strong base in the second inorganic strong base aqueous solution preferably comprises sodium hydroxide and / or potassium hydroxide, and in the embodiment, it is specifically sodium hydroxide. The mass percentage of the inorganic strong base in the second inorganic strong base aqueous solution is preferably 45-50%. The molar ratio of the bisphenol F to the inorganic strong base in the second inorganic strong base aqueous solution is preferably 0.5:(0.9-1).

[0046] In the present application, the temperature of the ring-closing reaction is preferably 60-63℃. The negative pressure condition of the ring-closing reaction is preferably -78-80 kPa.

[0047] In the present application, the dropping comprises sequentially performing first-stage dropping, second-stage dropping and third-stage dropping, and the total time of dropping the second inorganic strong base aqueous solution is specifically 3 h. The time of the first-stage dropping, the time of the second-stage dropping and the time of the third-stage dropping are preferably 1 h respectively. The mass percentage of the second inorganic strong base aqueous solution in the first-stage dropping to the total mass of the second inorganic strong base aqueous solution is preferably 25-30%, and more preferably 29%, 25%, 28% or 30%. The mass percentage of the second inorganic strong base aqueous solution in the second-stage dropping to the total mass of the second inorganic strong base aqueous solution is preferably 30-32%, and more preferably 32% or 30%. The mass percentage of the second inorganic strong base aqueous solution in the third-stage dropping to the total mass of the second inorganic strong base aqueous solution is preferably 38-45%, and more preferably 39%, 45%, 40% or 38%. Preferably, the mass of the second inorganic strong base aqueous solution in the first-stage dropping < the mass of the second inorganic strong base aqueous solution in the second-stage dropping < the mass of the second inorganic strong base aqueous solution in the third-stage dropping.

[0048] In the present application, during the ring-closing reaction, the epichlorohydrin is subjected to azeotropic distillation with water to obtain azeotropic distillation product, and the epichlorohydrin obtained by separating water from the azeotropic distillation product is refluxed to continue the ring-closing reaction. The separation of water preferably adopts layer separation by a water trap. The dropping is completed, and the ring-closing reaction is ended.

[0049] In the present application, the second inorganic strong base aqueous solution is dropped to obtain a ring-closing reaction liquid. After obtaining the ring-closing reaction liquid, the present application preferably further comprises: removing the epichlorohydrin from the ring-closing reaction liquid to obtain a bisphenol F epoxy resin crude reaction liquid.

[0050] The bisphenol F epoxy resin crude reaction liquid and a first organic solvent are mixed to obtain a mixed solution. A third inorganic strong base aqueous solution is added dropwise to the mixed solution to perform a refining reaction, and a refined reaction liquid is obtained.

[0051] The refined reaction liquid and an extraction solvent are mixed and then left to separate into layers to obtain an oil phase product. The extraction solvent is a second organic solvent, or a second organic solvent and water.

[0052] The oil phase product is obtained by neutralization, water washing and desolventizing the oil phase product in sequence.

[0053] The crude reaction solution of bisphenol F epoxy resin is obtained by removing the epichlorohydrin from the closed loop reaction solution. In the present application, the method for removing the epichlorohydrin is preferably vacuum distillation, the temperature for removing the epichlorohydrin is preferably 105℃, and the vacuum degree is preferably -98 kPa. The crude reaction solution of bisphenol F epoxy resin is obtained by cooling the closed loop reaction solution after removing the epichlorohydrin.

[0054] After obtaining the crude reaction solution of bisphenol F epoxy resin, the crude reaction solution of bisphenol F epoxy resin is mixed with a first organic solvent to obtain a mixed solution, and a third inorganic strong base aqueous solution is added dropwise into the mixed solution to perform a refining reaction to obtain a refined reaction solution. In the present application, the first organic solvent preferably includes toluene or methyl isobutyl ketone (MIBK). The inorganic strong base in the third inorganic strong base aqueous solution preferably includes sodium hydroxide and / or potassium hydroxide, and the mass percentage of the inorganic strong base in the third inorganic strong base aqueous solution used in the refining reaction is preferably 30-32%. The molar ratio of the inorganic strong base in the third inorganic strong base aqueous solution used in the refining reaction to the bisphenol F is preferably (0.14-0.15):0.5. The temperature of the refining reaction is preferably 80-90℃, the dropping time of the third inorganic strong base aqueous solution in the refining reaction is preferably 20-30 min, and the holding reaction time of the refining reaction is preferably 1-1.5 h after the dropping is completed. The holding reaction time of the refining reaction is preferably calculated from the beginning of the dropping of the third inorganic strong base aqueous solution. The holding reaction of the refining reaction is performed under stirring.

[0055] After obtaining the refined reaction solution, the refined reaction solution is mixed with an extraction solvent to obtain an oil phase product after standing and layering. The extraction solvent is a second organic solvent or a second organic solvent and water. In the present application, the second organic solvent preferably includes toluene or methyl isobutyl ketone (MIBK). When the extraction solvent is a second organic solvent, the second organic solvent is preferably MIBK. When the extraction solvent is a second organic solvent and water, the second organic solvent is preferably toluene. The mass ratio of toluene to water is preferably 13:21. In the present application, the standing and layering obtain a water phase, an oil-water transition layer and an oil layer. After obtaining the oil-water transition layer, the present application preferably further includes filtering the oil-water transition layer to remove aged resin. The present application preferably separates and removes the aged resin from the oil-water transition layer by filtering, and then combines the oil phase obtained after filtering with the oil phase product obtained by standing and layering.

[0056] After the oil phase product is obtained by layering, the oil phase product is sequentially subjected to neutralization, water washing and desolventizing to obtain a refined product of the bisphenol F epoxy resin. The reagent used in the neutralization is preferably an aqueous sodium dihydrogen phosphate solution, and the mass percentage of sodium dihydrogen phosphate in the aqueous sodium dihydrogen phosphate solution is preferably 0.5-1%. The neutralized oil phase product obtained after the neutralization is subjected to water washing, and the specific embodiment of the desolventizing is preferably negative pressure distillation.

[0057] The bisphenol F epoxy resin prepared by the method has a linear structure and an epoxy group as an end group.

[0058] In summary, by controlling the two reaction stages, the present application can control the side reactions to the minimum, thereby obtaining a linear epoxy resin with an epoxy group as an end group and a predetermined relative molecular mass.

[0059] In order to further illustrate the present application, the technical solutions provided by the present application are described in detail below in combination with examples, but they should not be understood as limiting the scope of protection of the present application.

[0060] Example 1

[0061] The specific operation process of the method for preparing the bisphenol F epoxy resin provided in this example is as follows:

[0062] 1. Ring-opening reaction: 110.8 g of bisphenol F with a content of 90.4% (0.5 mol) and 99.9% epichlorohydrin 370.4 g (4 mol) are put into a reaction bottle, nitrogen protection is performed during the process, the nitrogen flow is 15 L / h, the stirring is warmed to 50°C, 6.4 g of sodium hydroxide aqueous solution (50 wt%, NaOH 0.08 mol) is added for pre-reaction, the temperature is kept at this temperature for 2 h, and the ring-opening reaction generates chlorohydrin ether, and the conversion rate of bisphenol F is 92.4%.

[0063] 2. Ring-closing reaction: after the temperature keeping is finished, the nitrogen is closed, the temperature is warmed to 60°C, and a micro-negative pressure of -80 kPa is formed, 73 g of sodium hydroxide aqueous solution (50 wt%, NaOH 0.91 mol) is added dropwise at this temperature, the dropwise adding speed is controlled during the process, the dropwise adding time is 3 h (21.2 g is added dropwise in the first hour, 23.4 g is added dropwise in the middle hour, and 28.4 g is added dropwise in the last hour), during the reaction process, the epichlorohydrin is kept in azeotropic distillation with water, the water is separated after layering through a water trap, and the epichlorohydrin is returned to the reaction kettle to continue participating in the reaction, after the dropwise adding is finished, the temperature is slowly warmed to 105°C, the vacuum degree is adjusted to -98 kPa to remove ECH, and when there is basically no material, the temperature is lowered.

[0064]

[0065] Example 2

[0066] The specific operation process of the preparation method of the bisphenol F epoxy resin provided in this example is as follows:

[0067] <1> Ring-opening reaction: 110.8 g of bisphenol F with a content of 90.4% (0.5 mol) and 99.9% epichlorohydrin 231.5 g (2.5 mol) were put into a reaction bottle, and nitrogen protection was performed during the process with a flow rate of 20 L / h. The mixture was stirred and heated to 50°C, 6.4 g of sodium hydroxide solution (50 wt%, NaOH 0.08 mol) was added for pre-reaction, and the reaction was maintained at this temperature for 2 h to generate chlorohydrin ether by ring-opening reaction, and the conversion rate of bisphenol F was 87.5%.

[0068] <2> Ring-closing reaction: after the temperature was maintained, the nitrogen was turned off, the temperature was increased to 60°C, and a slight negative pressure of-80 kPa was maintained. 81 g of sodium hydroxide solution (45 wt%, NaOH 0.91 mol) was added dropwise at this temperature, and the dropwise addition speed was controlled. The dropwise addition time was 3 h (20.2 g was added in the first hour, 24.3 g was added in the middle hour, and 36.5 g was added in the last hour). During the reaction, the epichlorohydrin was distilled with water through a water separator, and the water was separated at the same time. The epichlorohydrin was returned to the reaction kettle for continuous reaction. After the dropwise addition was completed, the temperature was slowly increased to 105°C, the vacuum degree was adjusted to-98 kPa to remove ECH, and the temperature was decreased when there was basically no material.

[0069] <3> Refining: 104 g of the first organic solvent toluene was added to the above kettle material, and the mixture was stirred and heated to 80°C. 19 g of sodium hydroxide solution (32 wt%, NaOH 0.15 mol) was added dropwise for 30 min. After the dropwise addition was completed, the mixture was stirred for 1 h. The second organic solvent 130 g of toluene and 210 g of water were added for stirring. After dissolution, the water layer was separated by standing. The oil-water transition layer was separated by filtration to remove the aged resin. The oil phase obtained after the removal of the aged resin and the oil layer obtained by standing were combined. Then, the oil layer was neutralized with 1% sodium dihydrogen phosphate aqueous solution. After the separation, 100 g of water was added to the oil layer for water washing. Finally, the oil layer obtained was subjected to negative pressure to remove the solvent toluene to obtain the bisphenol F epoxy resin product.​

[0070] Example 3

[0071] The specific operation process of the preparation method of the bisphenol F epoxy resin provided in this example is as follows:

[0072] 1. Ring-opening reaction: 110.8 g of bisphenol F with a content of 90.4% (0.5 mol) and 370.4 g of 99.9% epichlorohydrin (4 mol) were put into a reaction bottle, and nitrogen protection was performed during the process at a flow rate of 15 L / h. The stirring was heated to 55°C, 10 g of sodium hydroxide aqueous solution (32 wt%, NaOH 0.08 mol) was added for pre-reaction, and the reaction was kept at this temperature for 2 h. The ring-opening reaction generated chlorohydrin ether, and the conversion rate of bisphenol F was 93.1%.

[0073] 2. Ring-closing reaction: after the temperature was kept, the nitrogen was turned off, and the temperature was increased to 60°C with a slight negative pressure of-80 kPa. 73 g of sodium hydroxide aqueous solution (50 wt%, NaOH 0.91 mol) was added dropwise at this temperature, and the dropwise addition speed was controlled. The dropwise addition time was 3 h (20.4 g was added in the first hour, 23.4 g was added in the middle hour, and 29.2 g was added in the last hour). During the reaction process, the epichlorohydrin was distilled with water through a water separator, and the water was separated at the same time. The epichlorohydrin was returned to the reaction kettle for continuous reaction. After the dropwise addition was completed, the temperature was slowly increased to 105°C, the vacuum degree was adjusted to-98 kPa to remove ECH, and when there was basically no material, the temperature was decreased.

[0074] 3. Refining: 100 g of MIBK was added to the above kettle material, and the stirring was heated to 80°C. 18.1 g of sodium hydroxide aqueous solution (32 wt%, NaOH 0.14 mol) was added dropwise for 30 min. After the dropwise addition was completed, the temperature was kept and stirred for 1 h. 120 g of MIBK was added as the second organic solvent for stirring. After dissolution, the water layer was separated by standing, and the oil-water transition layer was separated by filtration to remove the aged resin. Then, the oil phase obtained after the above steps was combined with the oil layer obtained by standing. The oil layer was then neutralized with 0.5% sodium dihydrogen phosphate aqueous solution, and the oil layer was separated after layering. Then, 100 g of water was added to the oil layer for water washing. Finally, the oil layer obtained after the separation was subjected to negative pressure to remove the solvent MIBK, and the bisphenol F epoxy resin product was obtained.

[0075] Example 4

[0076] The specific operation process of the preparation method of the bisphenol F epoxy resin provided in this example is as follows:

[0077]

[0078]

[0079]

[0080] Comparative Example 1

[0081] The specific operation process of the preparation method of the bisphenol F epoxy resin provided in the comparative example is as follows:

[0082]

[0083] ​​​​(2) Closing loop reaction: after the end of the heat preservation, close the nitrogen, and raise the temperature to 60°C, with a micro negative pressure of -80 kPa, at this temperature, drop 114 g of sodium hydroxide aqueous solution (32wt%, NaOH 0.91 mol), control the drop speed during the process, the drop time is 3h (drop 33.2g in the first hour, drop 36.5g in the middle hour, and drop 44.3g in the last hour), during the reaction, maintain the azeotropic distillation of epichlorohydrin and water, separate the water after layering through the water trap, and return the epichlorohydrin to the reaction kettle to continue participating in the reaction, after the drop is completed, slowly raise the temperature to 105°C, adjust the vacuum degree to -98 kPa to remove ECH, and when there is basically no material, reduce the temperature.

[0084] (4) Refining: add 104 g of the first organic solvent toluene to the above kettle material, stir and raise the temperature to 80°C, start dropping 19 g of sodium hydroxide aqueous solution (32wt%, NaOH 0.15 mol), which takes 30 min, after the drop is completed, heat preservation and stirring for 1h, add the second organic solvent 130 g of toluene and 210 g of water for stirring, after dissolving, stand to separate the water layer, filter the oil-water transition layer to remove the aged resin, then combine the oil phase obtained after the above steps and the oil layer obtained by standing, then neutralize the oil layer with 0.5% sodium dihydrogen phosphate aqueous solution, separate the layers, then add 100 g of water to the oil layer for water washing, and finally separate the oil layer to remove the solvent toluene under negative pressure to obtain the bisphenol F epoxy resin product.

[0085] Comparative Example 2

[0086] The specific operation process of the preparation method of the bisphenol F epoxy resin provided in the present comparative example is as follows:

[0087] (1) Opening loop reaction: put 110.8 g of bisphenol F with a content of 90.4% (0.5 mol) and 99.9% epichlorohydrin 370.4 g (4 mol) into the reaction bottle, protect with nitrogen during the process, the flow rate is 15 L / h, stir and raise the temperature to 50°C, add 1.76 g of benzyltrimethylammonium chloride, 6.4 g of sodium hydroxide aqueous solution (50wt%, NaOH 0.08 mol) for pre-reaction, heat preservation at this temperature for 2h, and the conversion rate of bisphenol F is 89.3% after the opening loop reaction to generate chlorohydrin ether.

[0088] (2) Closing loop reaction: after the end of the heat preservation, close the nitrogen, and raise the temperature to 60°C with a micro-negative pressure of -80 kPa. At this temperature, drop 73 g of sodium hydroxide aqueous solution (50 wt%, NaOH 0.91 mol) at a controlled dropping speed. The dropping time is 3 h (21.2 g is dropped in the first hour, 23.4 g is dropped in the middle hour, and 28.4 g is dropped in the last hour). During the reaction, maintain the azeotropic distillation of epichlorohydrin and water. After the water is separated through a water trap, the epichlorohydrin is returned to the reactor for continuous reaction. Slowly raise the temperature to 102°C, adjust the vacuum degree to -98 kPa to remove ECH, and then reduce the temperature when there is basically no output.

[0089] (4) Refining: add 104 g of the first organic solvent toluene to the above-mentioned kettle material, stir, and raise the temperature to 80°C. Then, drop 19 g of sodium hydroxide aqueous solution (32 wt%, NaOH 0.15 mol) for 30 min. After the dropping is completed, heat preservation and stirring are performed for 1 h. Then, add the second organic solvent 130 g of toluene and 210 g of water for stirring. After dissolution, separate the water layer by standing. The oil-water transition layer is filtered and separated to remove the aged resin. Then, the oil phase obtained after the above-mentioned operation is combined with the oil layer obtained by standing. Then, the oil layer is neutralized with 1% sodium dihydrogen phosphate aqueous solution. After the separation, the oil layer is continuously washed with 100 g of water. Finally, the oil layer obtained after the separation is dehydrated under a negative pressure to remove the solvent toluene, thereby obtaining the bisphenol F epoxy resin product.

[0090] Comparative Example 3

[0091] The difference from Example 1 is that the dropping time of the base in the closing loop reaction is 3 h (the base is dropped at a uniform speed during the process). The remaining operations are the same as those in Example 1.

[0092] Comparative Example 4

[0093] The difference from Example 1 is that the dropping time of the base in the closing loop reaction is 3 h (the base is dropped at a uniform speed during the process). The remaining operations are the same as those in Example 1.

[0094] Comparative Example 5

[0095] The difference from Example 1 is that the dropping time of the base in the closing loop reaction is 3 h (the base is dropped at a uniform speed during the process). The remaining operations are the same as those in Example 1.

[0096] Comparative Example 6

[0097] The difference from Example 1 is that the time for dropping base in the ring-closing reaction is 3 h (the amount of base dropped in the first stage is 20% of the total amount of base for ring-closing, the amount of base dropped in the second stage is 30% of the total amount of base for ring-closing, and the amount of base dropped in the third stage is 50% of the total amount of base for ring-closing), and the rest of the operations are exactly the same as in Example 1.

[0098] Comparative Example 7

[0099] The specific operation process of the preparation method of the bisphenol F epoxy resin provided in the present comparative example is as follows:

[0100] 1. Ring-opening reaction: 110.8 g of bisphenol F with a content of 90.4% (0.5 mol) and 370.4 g of 99.9% epichlorohydrin (4 mol) were put into a reaction bottle, and nitrogen protection was performed during the process at a flow rate of 15 L / h. The stirring was heated to 50°C, 170 g of isobutyl alcohol, and 6.4 g of sodium hydroxide aqueous solution (50 wt%, NaOH 0.08 mol) were added for pre-reaction. The reaction was kept at this temperature for 2 h, and a chlorohydrin ether was generated by ring-opening reaction, and the conversion rate of bisphenol F was 88.3%.

[0101] 2. Ring-closing reaction: after the temperature was kept, the nitrogen was turned off, and the temperature was raised to 60°C. With a micro-negative pressure of -80 kPa, 73 g of sodium hydroxide aqueous solution (50 wt%, NaOH 0.91 mol) was added dropwise at this temperature. The dropping speed was controlled, and the dropping time was about 3 h (21.2 g was added in the first hour, 23.4 g was added in the middle hour, and 28.4 g was added in the last hour). During the reaction process, the epichlorohydrin was distilled with water azeotropically, and the water was separated after being layered through a water trap, and the epichlorohydrin was returned to the reaction kettle for continuous reaction. After the dropping was completed, the temperature was slowly raised to 102°C, the vacuum degree was adjusted to -98 kPa to remove isobutyl alcohol and ECH, and when there was basically no discharge, the temperature was lowered.

[0102] 3. Refining: 104 g of toluene as the first organic solvent was added to the above-mentioned kettle material, and the stirring was heated to 80°C. 19 g of sodium hydroxide aqueous solution (32 wt%, NaOH 0.15 mol) was added dropwise for 30 min. After the dropping was completed, the temperature was kept and stirred for 1 h. 130 g of toluene and 210 g of water as the second organic solvent were added for stirring. After being dissolved, the water layer was separated after standing. The oil-water transition layer was filtered and separated to remove the aged resin. Then, the oil phase obtained and the oil layer obtained by standing were combined. The oil layer was then neutralized with 1% sodium dihydrogen phosphate aqueous solution. After being layered, the oil layer was further washed with 100 g of water. Finally, the oil layer obtained by separation was subjected to negative pressure to remove the solvent toluene, and the bisphenol F epoxy resin product was obtained.

[0103] Test Example

[0104] Analysis result test:

[0105] The epoxy equivalent, total chlorine, hydrolytic chlorine, viscosity and inorganic chlorine of the products prepared in Examples 1-4 and Comparative Examples 1-7 were tested, and the specific results are shown in Table 1.

[0106] Table 1: Test results of properties of products prepared in Examples 1-4 and Comparative Examples 1-7

[0107]

[0108] As shown in Table 1, compared with Example 1, in Comparative Example 1, the molar amount of sodium hydroxide in the aqueous sodium hydroxide solution used in step (1) and step (2) is unchanged, but the mass of water is increased, that is, the molar concentration of the strong sodium hydroxide solution used in step (1) and step (2) is reduced, and too much water in the reaction process will promote the hydrolysis reaction of epichlorohydrin under alkaline conditions to generate glycerol, which further adds to the generated epoxy resin, thereby deteriorating the product quality, and ultimately resulting in the increase of the hydrolytic chlorine content, viscosity and inorganic chlorine content of the obtained bisphenol F epoxy resin product.

[0109] Compared with Example 1, in Comparative Example 2, 1.76 g of benzyltrimethylammonium chloride is additionally added in step (1), resulting in the increase of the hydrolytic chlorine content, viscosity, inorganic chlorine content and water content of the obtained bisphenol F epoxy resin product, and the addition of the additive will increase the wastewater treatment procedure and make the production cost higher.

[0110] Compared with Example 1, in Comparative Example 3, the aqueous sodium hydroxide solution is uniformly dropped in step (2), resulting in the increase of the hydrolytic chlorine content, viscosity, inorganic chlorine content and water content of the obtained bisphenol F epoxy resin product.

[0111] Compared with Example 1, in Comparative Examples 4-6, the dropping speed in step (2) is changed, resulting in the increase of the hydrolytic chlorine content, viscosity, inorganic chlorine content and water content of the obtained bisphenol F epoxy resin product.

[0112] Compared with Example 1, in Comparative Example 7, 170 g of isobutyl alcohol is additionally added in step (1), and the quality of the obtained bisphenol F epoxy resin product does not change much compared with Example 1, but the addition of the solvent requires additional equipment for separation and recovery of the solvent, and increases the energy consumption, making the production cost of the bisphenol F epoxy resin higher.

[0113] In summary, the two-step process of the present application does not require the addition of additives or solvents in the reaction, reduces the operation and energy consumption of the later separation of the solvent, controls the conversion rate by optimizing the amount of pre-reaction catalyst, reduces the hydrolytic chlorine of the crude resin, reduces the side reaction, and uses the negative pressure segmented liquid alkali process in the main reaction process, thereby improving the product quality by controlling the dropping speed of the alkali and the water output.

[0114] From the above examples, the present application provides a kind of efficient, easy to operate and control, mild conditions process, reaction process uses inorganic strong base (sodium hydroxide) as catalyst, without adding quaternary ammonium salt and other adjuvants, can realize the circulation economy of electrolysis after the treatment of refined separation wastewater, green emission reduction low carbon, main reaction uses negative pressure subsection liquid alkali process, effectively improves the utilization of alkali, reduces raw material consumption, reduces side reaction, improves the product performance of epoxy resin, suitable for industrial production.

[0115] Although the above examples make a detailed description of the present application, it is only a part of the embodiments of the present application, not all embodiments, and other embodiments can be obtained under the premise of not being creative according to the present embodiment, and these embodiments all belong to the protection scope of the present application.

Claims

1. A method for preparing bisphenol F epoxy resin, characterized in that, Includes the following steps: In a protective gas atmosphere, bisphenol F, epichlorohydrin and an aqueous solution of a first inorganic strong base are mixed and subjected to an etherification reaction, wherein the inorganic strong base in the first aqueous solution has a mass percentage content of 32-50%, and a reaction solution containing chlorohydrin ether is obtained. Under negative pressure, a second inorganic strong base aqueous solution is added dropwise to the reaction solution containing chlorohydrin ether to carry out a ring-closure reaction. The inorganic strong base in the second inorganic strong base aqueous solution has a mass percentage of 45-50%, yielding bisphenol F epoxy resin. The dropwise addition includes a first stage dropwise addition, a second stage dropwise addition, and a third stage dropwise addition. The time for the first stage dropwise addition, the time for the second stage dropwise addition, and the time for the third stage dropwise addition each account for 1 / 3 of the total dropwise addition time. The mass percentage of the second inorganic strong base aqueous solution added in the first stage dropwise is 25-30% of the total mass of the second inorganic strong base aqueous solution, the mass percentage of the second inorganic strong base aqueous solution added in the second stage dropwise is 30-32% of the total mass of the second inorganic strong base aqueous solution, and the mass percentage of the second inorganic strong base aqueous solution added in the third stage dropwise is 38-45% of the total mass of the second inorganic strong base aqueous solution. During the ring-closure reaction, epichlorohydrin and water are azeotropically distilled to obtain an azeotropic distillation product. The epichlorohydrin obtained after separating water from the azeotropic distillation product is refluxed to continue the ring-closure reaction.

2. The preparation method according to claim 1, characterized in that, After the second inorganic strong base aqueous solution is added dropwise, a closed-loop reaction solution is obtained. Then, epichlorohydrin is removed from the closed-loop reaction solution to obtain a crude reaction solution of bisphenol F epoxy resin. The crude reaction solution of bisphenol F epoxy resin is mixed with a first organic solvent to obtain a mixed solution; a third inorganic strong base aqueous solution is added dropwise to the mixed solution to carry out a purification reaction to obtain a purified reaction solution; The purified reaction solution and the extraction solvent are mixed and allowed to stand to separate into layers to obtain an oil phase product; the extraction solvent is a second organic solvent, or a second organic solvent and water; The oil phase product was then subjected to neutralization, washing with water, and desolventizing in sequence to obtain a refined bisphenol F epoxy resin.

3. The preparation method according to claim 1, characterized in that, The inorganic strong base in the first inorganic strong base aqueous solution includes sodium hydroxide and / or potassium hydroxide; The molar ratio of the inorganic strong base to the bisphenol F in the first inorganic strong base aqueous solution is 0.15~0.16:

1.

4. The preparation method according to claim 1, characterized in that, The molar ratio of bisphenol F to epichlorohydrin is 0.5:(2.5~4). The protective gas is nitrogen, and the flow rate of the protective gas is 15~20L / h.

5. The preparation method according to claim 1 or 3, characterized in that, The conversion rate of bisphenol F in the etherification reaction is 87-94%.

6. The preparation method according to claim 1, 3, or 4, characterized in that, The etherification reaction was carried out at a temperature of 50-55°C for 2 hours.

7. The preparation method according to claim 1, characterized in that, The closed-loop reaction is carried out at a temperature of 60~63℃ and under a negative pressure of -78~80kPa.

8. The preparation method according to claim 1 or 7, characterized in that, The inorganic strong base in the second inorganic strong base aqueous solution includes sodium hydroxide and / or potassium hydroxide; The total time for adding the second inorganic strong base aqueous solution was 3 hours. The molar ratio of bisphenol F to the inorganic strong base in the second inorganic strong base aqueous solution is 0.5:(0.9~1).

9. The preparation method according to claim 2, characterized in that, The first organic solvent and the second organic solvent include toluene or methyl isobutyl ketone; The inorganic strong base in the third inorganic strong base aqueous solution includes sodium hydroxide and / or potassium hydroxide; The inorganic strong base in the third inorganic strong base aqueous solution has a mass percentage content of 30-32%. The molar ratio of the inorganic strong base to the bisphenol F in the third inorganic strong base aqueous solution is (0.14~0.15):0.

5.

10. The preparation method according to claim 2 or 9, characterized in that, The temperature of the purification reaction is 80~90℃, the dripping time of the third inorganic strong base aqueous solution is 20~30min, and after the dripping is completed, the temperature is kept for 1~1.5h.

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