A chromium oxide-lithium perchlorate composite catalyst, its preparation method and its application in the preparation of bisphenol F

Abstract

The present invention belongs to the technical field of organic synthesis, and in particular to a chromium oxide-lithium perchlorate composite catalyst and its preparation method and application in the preparation of bisphenol F. The chromium oxide-lithium perchlorate composite catalyst provided by the present invention has an affinity for the inorganic phase and the organic phase in the bisphenol F reaction system, can make phosphoric acid better contact with phenol and paraformaldehyde during the condensation reaction, reduce surface tension and surface free energy, thereby improving the yield of bisphenol F, in an acidic medium, the chromium oxide-lithium perchlorate composite catalyst combines the carbon cation of formaldehyde with phosphoric acid to generate a semi-phosphorus-based ketal, increases the steric effect, improves the selectivity of the condensation reaction, and thus the chromium oxide-lithium perchlorate composite catalyst has a stronger catalytic effect and better selectivity for the reaction process of preparing bisphenol F, can effectively reduce the content of by-products in the process of synthesizing bisphenol F resin, improve product yield and the proportion of 4,4'-dihydroxydiphenylmethane.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis, and particularly relates to a chromium oxide-lithium perchlorate composite catalyst, a preparation method thereof, and application thereof in the preparation of bisphenol F. Background Art

[0002] Bisphenol F epoxy resin, a new epoxy resin, was developed to reduce the operating viscosity of bisphenol A epoxy resin. It shares a similar structure with bisphenol A epoxy resin. Research has found that bisphenol F epoxy resin not only possesses most of the excellent properties of bisphenol A epoxy resin, but more importantly, its room temperature viscosity is only 1 / 4 to 1 / 7 of that of bisphenol A epoxy resin, requiring no additives to reduce its viscosity during use. Furthermore, bisphenol F epoxy resin can be cured at low temperatures, thus expanding its application range. Its mechanical properties have also been found to be far superior to bisphenol A epoxy resin, making this polymer material increasingly popular in the military, large-scale shipbuilding, and wind power industries.

[0003] Bisphenol F (BPF) is a mixture of 4,4'-, 2,2'- and 2,4'-dihydroxydiphenylmethane, usually prepared by the condensation of phenol and formaldehyde in the presence of a Lewis acid catalyst. The ratio of isomers in bisphenol F not only determines the performance of bisphenol F, but also affects the performance of the subsequent synthesized product, bisphenol F epoxy resin. Among them, 4,4'-dihydroxydiphenylmethane has the best performance and is considered to be an excellent substitute for bisphenol A in the field of epoxy resins and polycarbonates. However, the current industrialization level of bisphenol F epoxy resin is not high, mainly because the yield of bisphenol F is not high. Due to the lack of a good catalyst, all three isomers will be generated in the reaction, resulting in a small proportion of 4,4'-dihydroxydiphenylmethane. Summary of the Invention

[0004] In view of this, the object of the present invention is to provide a chromium oxide-lithium perchlorate composite catalyst, a preparation method thereof, and an application thereof in the preparation of bisphenol F. The chromium oxide-lithium perchlorate composite catalyst provided by the present invention can increase the yield of bisphenol F and the proportion of 4,4'-dihydroxydiphenylmethane therein.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] The invention provides a chromium oxide-lithium perchlorate composite catalyst, comprising lithium perchlorate and chromium oxide wrapping the lithium perchlorate.

[0007] Preferably, the mass ratio of chromium oxide to lithium perchlorate in the chromium oxide-lithium perchlorate composite catalyst is 2 to 4:1; the particle size of lithium perchlorate in the chromium oxide-lithium perchlorate composite catalyst is 2 to 30 nm; the particle size of the chromium oxide-lithium perchlorate composite catalyst is 10 to 100 nm; the specific surface area of ​​the chromium oxide-lithium perchlorate composite catalyst is 100 to 500 m 2 / g.

[0008] The present invention also provides a method for preparing the chromium oxide-lithium perchlorate composite catalyst described in the above technical solution, comprising the following steps:

[0009] Mixing chromium oxide, an organic solvent and a complexing agent, adjusting the pH value of the resulting mixture to 2-4, and then performing a complexing reaction to obtain a chromium oxide sol;

[0010] dissolving lithium perchlorate in a mixed solution of oxalic acid and hydrochloric acid to obtain a lithium perchlorate solution;

[0011] The chromium oxide sol and the lithium perchlorate solution are mixed and heated to obtain a chromium oxide-lithium perchlorate composite catalyst.

[0012] Preferably, the complexing agent comprises glacial acetic acid.

[0013] Preferably, the mass ratio of the chromium oxide to the complexing agent is 1:5-10.

[0014] Preferably, the temperature of the complexation reaction is 30 to 70° C.; and the time of the complexation reaction is 10 to 30 minutes.

[0015] The present invention also provides the use of the chromium oxide-lithium perchlorate composite catalyst described in the above technical solution or the chromium oxide-lithium perchlorate composite catalyst prepared by the preparation method described in the above technical solution in the preparation of bisphenol F.

[0016] The present invention also provides a method for preparing bisphenol F, which is characterized by comprising the following steps:

[0017] Phenol, paraformaldehyde, phosphoric acid and a chromium oxide-lithium perchlorate composite catalyst are mixed and subjected to a condensation reaction to obtain bisphenol F;

[0018] The chromium oxide-lithium perchlorate composite catalyst is the chromium oxide-lithium perchlorate composite catalyst described in the above technical solution or the chromium oxide-lithium perchlorate composite catalyst prepared by the preparation method described in the above technical solution.

[0019] Preferably, the mass ratio of the phenol to the chromium oxide-lithium perchlorate composite catalyst is 50 to 100:1.

[0020] Preferably, the temperature of the condensation reaction is 35 to 55° C.; and the time of the condensation reaction is 1 to 5 hours.

[0021] The present invention provides a chromium oxide-lithium perchlorate composite catalyst, comprising lithium perchlorate and chromium oxide encapsulating the lithium perchlorate. The chromium oxide-lithium perchlorate composite catalyst contains LiClO4 and Cr2O3, which respectively have affinity for the inorganic phase and organic phase in the bisphenol F reaction system. This allows phosphoric acid to better contact with phenol and paraformaldehyde during the condensation reaction, reducing surface tension and surface free energy, thereby increasing the yield of bisphenol F. In an acidic medium, the chromium oxide-lithium perchlorate composite catalyst combines the carbon cation of formaldehyde with phosphoric acid to form a hemiphosphorus-based ketal, increasing the steric effect and improving the selectivity of the condensation reaction. As a result, the chromium oxide-lithium perchlorate composite catalyst has a stronger catalytic effect and better selectivity in the reaction process of preparing bisphenol F, can effectively reduce the content of by-products in the synthesis of bisphenol F resin, and improve the product yield and the proportion of 4,4'-dihydroxydiphenylmethane.

[0022] The present invention utilizes the chromium oxide-lithium perchlorate composite catalyst provided by the present invention, and further provides a method for preparing bisphenol F. Compared with common bisphenol F preparation methods such as the phosphoric acid method and the oxalic acid method, both the overall yield and the proportion of 4,4'-dihydroxydiphenylmethane are significantly improved. The chromium oxide-lithium perchlorate composite catalyst remains in the phosphoric acid layer and can be filtered and reused repeatedly. At the same time, the use of paraformaldehyde instead of the formaldehyde aqueous solution can effectively reduce the water content in the system, allowing the reaction to proceed in a better forward direction. At the same time, the concentration of the recovered phosphoric acid is increased, allowing the phosphoric acid to be reused multiple times, greatly reducing costs. DETAILED DESCRIPTION

[0023] The invention provides a chromium oxide-lithium perchlorate composite catalyst, comprising lithium perchlorate and chromium oxide wrapping the lithium perchlorate.

[0024] In the present invention, the particle size of the chromium oxide-lithium perchlorate composite catalyst is preferably 10 to 100 nm, more preferably 20 to 60 nm; the specific surface area of ​​the chromium oxide-lithium perchlorate composite catalyst is preferably 100 to 500 m 2 / g, more preferably 150 to 300 m 2 ; The mass ratio of chromium oxide and lithium perchlorate in the chromium oxide-lithium perchlorate composite catalyst is preferably 2 to 4:1, more preferably 2.5 to 4:1; the particle size of lithium perchlorate in the chromium oxide-lithium perchlorate composite catalyst is preferably 2 to 30 nm, more preferably 5 to 10 nm.

[0025] The chromium oxide-lithium perchlorate composite catalyst provided by the present invention contains LiClO4 and Cr2O3, which respectively have affinity for the inorganic phase and the organic phase in the bisphenol F reaction system, can enable phosphoric acid to better contact with phenol and paraformaldehyde during the condensation reaction, reduce surface tension and surface free energy, and improve the condensation reaction effect. In an acidic medium, the chromium oxide-lithium perchlorate composite catalyst combines the carbon cation of formaldehyde with phosphoric acid to form a semi-phosphorus-based ketal, thereby increasing the steric effect and improving the selectivity of the condensation reaction. Therefore, the chromium oxide-lithium perchlorate composite catalyst has a stronger catalytic effect and better selectivity in the reaction process of preparing bisphenol F, can effectively reduce the content of by-products in the process of synthesizing bisphenol F resin, and improve the product yield and the proportion of 4,4'-dihydroxydiphenylmethane.

[0026] The present invention also provides a method for preparing the chromium oxide-lithium perchlorate composite catalyst, comprising the following steps:

[0027] Mixing chromium oxide, an organic solvent and a complexing agent, adjusting the pH value of the resulting mixture to 2-4, and then performing a complexing reaction to obtain a chromium oxide sol;

[0028] dissolving lithium perchlorate in a mixed solution of oxalic acid and hydrochloric acid to obtain a lithium perchlorate solution;

[0029] The chromium oxide sol and the lithium perchlorate solution are mixed and heated to obtain a chromium oxide-lithium perchlorate composite catalyst.

[0030] Unless otherwise specified, the present invention has no special requirements on the sources of the raw materials used, and commercially available products known to those skilled in the art can be used.

[0031] The invention mixes chromium oxide, an organic solvent and a complexing agent, adjusts the pH value of the obtained mixed solution to 2-4, and then performs a complexing reaction to obtain a chromium oxide sol.

[0032] In the present invention, the organic solvent preferably includes anhydrous ethanol; the complexing agent preferably includes glacial acetic acid; the mass concentration of the glacial acetic acid is preferably ≥99%, more preferably ≥99.5%; the mass ratio of the chromium oxide to the organic solvent is preferably 1:5-10, more preferably 1:5-8; the mass ratio of the chromium oxide to the complexing agent is preferably 1:5-10, more preferably 1:5-8.

[0033] In the present invention, the mixing of chromium oxide, organic solvent and complexing agent is preferably carried out under stirring; the stirring is preferably magnetic stirring; the stirring rate is preferably 200-500 rpm, more preferably 300-400 rpm; the stirring time is preferably 10-30 min, more preferably 15-20 min.

[0034] In the present invention, the pH value of the mixed solution is adjusted to 2-4, preferably 2.5-3.5; the reagent used to adjust the pH value of the mixed solution is preferably nitric acid; the mass concentration of the nitric acid is preferably 10-30%, more preferably 15-20%.

[0035] In the present invention, the temperature of the complex reaction is preferably 30-70°C, more preferably 40-60°C; the time of the complex reaction is preferably 10-30 min, more preferably 15-25 min; the complex reaction is preferably carried out in a water bath; the complex reaction is preferably carried out under stirring; the stirring is preferably magnetic stirring; the stirring rate is preferably 200-500 rpm, more preferably 300-400 rpm.

[0036] The invention dissolves lithium perchlorate in a mixed solution of oxalic acid and hydrochloric acid to obtain a lithium perchlorate solution.

[0037] In the present invention, the preparation method of the lithium perchlorate is preferably:

[0038] After mixing sodium perchlorate solution and lithium chloride, a double decomposition reaction is carried out to obtain lithium perchlorate.

[0039] In the present invention, the temperature of the metathesis reaction is preferably 40 to 80° C., more preferably 50 to 70° C.; the time of the metathesis reaction is preferably 1 to 4 hours, more preferably 2 to 3 hours; the mass concentration of sodium perchlorate in the sodium perchlorate solution is preferably 30 to 60%, more preferably 40 to 50%; the mass ratio of sodium perchlorate to lithium chloride in the sodium perchlorate solution is preferably 1 to 2:1, more preferably 1.2 to 1.6:1.

[0040] After the metathesis reaction, the present invention preferably further comprises: filtering the metathesis product to obtain sodium chloride and a filtrate; sequentially evaporating and concentrating the filtrate and cooling and crystallizing it to obtain a crude lithium perchlorate; and sequentially recrystallizing, centrifuging, and drying the crude lithium perchlorate to obtain lithium perchlorate. In the present invention, the recrystallization preferably comprises dissolving the crude lithium perchlorate in ethanol, filtering, and cooling and crystallizing the resulting filtrate. In the present invention, the temperature of the evaporation concentration is preferably 40 to 120° C., more preferably 70 to 120° C.; the time of the evaporation concentration is preferably 0.5 to 3 h, more preferably 1 to 2 h; the cooling crystallization method is preferably cooling with an ethanol aqueous solution in a water bath; the temperature of the cooling crystallization is preferably -20 to -5° C., more preferably -15 to -5° C.; the speed of the centrifugation is preferably 8000 to 20000 rpm, more preferably 10000 to 15000 rpm; the time of the centrifugation is preferably 10 to 60 min, more preferably 15 to 30 min; the temperature of the drying is preferably 40 to 80° C., more preferably 50 to 70° C.; the time of the drying is preferably 2 to 8 h, more preferably 3 to 6 h.

[0041] Due to the high chloride ion concentration in the hydrochloric acid system, most of the sodium chloride is precipitated, and sodium chloride and filtrate are obtained by filtration.

[0042] In the present invention, the volume ratio of oxalic acid to hydrochloric acid in the mixed solution of oxalic acid and hydrochloric acid is preferably 1:2-6, more preferably 1:2.5-4; the mass concentration of oxalic acid is preferably 5-10%, more preferably 6-8%; the mass concentration of hydrochloric acid is preferably 10-30%, more preferably 15-25%; the ratio of the mass of lithium perchlorate to the volume of the mixed solution of oxalic acid and hydrochloric acid is preferably (10-40) mg:(20-60) mL, more preferably (20-30) mg:(30-50) mL.

[0043] In the present invention, dissolving lithium perchlorate in a mixed solution of oxalic acid and hydrochloric acid is preferably carried out under stirring; the stirring rate is preferably 100 to 600 rpm, more preferably 200 to 400 rpm; and the stirring time is preferably 20 to 40 minutes, more preferably 25 to 35 minutes.

[0044] The present invention mixes the chromium oxide sol and the lithium perchlorate solution and then heats the mixture to obtain a chromium oxide-lithium perchlorate composite catalyst.

[0045] In the present invention, the volume ratio of the chromium oxide sol to the lithium perchlorate solution is preferably 2-4:1, more preferably 2.5-3.5:1; the heating temperature is preferably 100-200°C, more preferably 160°C; and the heating time is preferably 10-24h, more preferably 15-20h.

[0046] After the compounding, the present invention preferably further comprises: cooling, filtering, washing and drying the compounded product in sequence to obtain a chromium oxide-lithium perchlorate composite catalyst.

[0047] In the present invention, the cooling method is preferably cooling with an ethanol-water bath; the cooling to the temperature of the composite product is preferably -20 to -5°C, more preferably -10°C; the filtration is preferably negative pressure filtration; the washing liquid used for washing is preferably ethanol; the washing is performed until the filtrate is clear and transparent; the drying temperature is preferably 40 to 80°C, more preferably 50 to 70°C; the drying time is preferably 0.5 to 3 hours, more preferably 1 to 2 hours.

[0048] The present invention also provides the use of the chromium oxide-lithium perchlorate composite catalyst described in the above technical solution or the chromium oxide-lithium perchlorate composite catalyst prepared by the preparation method described in the above technical solution in the preparation of bisphenol F.

[0049] The present invention also provides a method for preparing bisphenol F, comprising the following steps:

[0050] Phenol, paraformaldehyde, phosphoric acid and chromium oxide-lithium perchlorate composite catalyst are mixed and subjected to condensation reaction to obtain bisphenol F.

[0051] In the present invention, the molar ratio of the phenol to the paraformaldehyde is preferably 2 to 6:1, more preferably 3 to 5:1; the molar ratio of the phenol to the phosphoric acid is preferably 2 to 6:1, more preferably 3 to 5:1; the mass concentration of the phosphoric acid is preferably 70 to 85%, more preferably 85%; the mass ratio of the phenol to the chromium oxide-lithium perchlorate composite catalyst is preferably 50 to 100:1, more preferably 60 to 80:1.

[0052] In the present invention, the mixing of phenol, paraformaldehyde, phosphoric acid and chromium oxide-lithium perchlorate composite catalyst is preferably performed by first heating phenol to melt, and then sequentially adding phosphoric acid, chromium oxide-lithium perchlorate composite catalyst and paraformaldehyde under stirring; the heating is preferably water bath heating; the water bath heating temperature is preferably 40-80° C., more preferably 45-55° C.; the water bath heating time is preferably 0.1-8 h, more preferably 0.5-6 h; the stirring rate is preferably 100-600 rpm, more preferably 200-400 rpm; the paraformaldehyde addition rate is preferably 10-50 g / h, more preferably 20-40 g / h.

[0053] The present invention uses the above mixing method to fully mix the reactants to form a homogeneous system, which is conducive to the forward progress of the reaction.

[0054] In the present invention, the temperature of the condensation reaction is preferably 35-55°C, more preferably 45°C; the time of the condensation reaction is preferably 1-5h, more preferably 5h; the condensation reaction is preferably carried out under stirring conditions; the stirring rate is preferably 100-600rpm, more preferably 200-400rpm.

[0055] In the condensation reaction, the present invention preferably subjects the product obtained from the condensation reaction to temperature-induced demixing. In the present invention, the temperature for temperature-induced demixing is preferably 60-100°C, more preferably 80°C; the time for temperature-induced demixing is preferably 10-60 minutes, more preferably 10-30 minutes; and the heating rate from the condensation reaction temperature to the temperature for temperature-induced demixing is preferably 5-20°C / min, more preferably 10-15°C / min. After the condensation reaction, the present invention heats the product to allow excess phenol to act as a solvent, facilitating demixing with phosphoric acid.

[0056] After the condensation reaction, the present invention preferably further comprises: allowing the product obtained from the condensation reaction to stand for a first time and then separating the liquids to obtain an inorganic phase and an organic phase; concentrating the inorganic phase to obtain a phosphoric acid aqueous solution; adjusting the pH value of the organic phase to 5, and then performing vacuum dehydration and cooling crystallization to obtain a crude bisphenol F product; dissolving the crude bisphenol F product in an alkaline solution, allowing it to stand for a second time, and then filtering to obtain an insoluble substance and a filtrate; adjusting the pH value of the filtrate to 4 to 5 to precipitate crystals, and filtering to obtain crystals; dissolving the crystals in toluene, and then sequentially performing cooling crystallization, filtering, and drying to obtain bisphenol F.

[0057] In the present invention, the phosphoric acid aqueous solution can be reused.

[0058] In the present invention, the first standing time is preferably 0.5 to 6 hours, more preferably 1 to 3 hours; the concentration temperature is preferably 20 to 80°C, more preferably 40 to 60°C; the concentration time is preferably 0.5 to 4 hours, more preferably 1 to 3 hours; the reagent used to adjust the pH value of the organic phase is preferably sodium bicarbonate solution; the mass concentration of the sodium bicarbonate solution is preferably 2 to 10%, more preferably 4 to 8%; the vacuum dehydration temperature is preferably 120 to 160°C, more preferably 130 to 150°C; the vacuum dehydration time is preferably 1 to 6 hours, more preferably 2 to 4 hours; the pressure of the vacuum dehydration is preferably -0.06 to -0.09 MPa, more preferably -0.08 MPa; the temperature of the cooling crystallization is preferably -20 to -5°C, more preferably -15 to -10°C; the time of the cooling crystallization is preferably 0.5 to 3 hours, more preferably 1 to 2 hours; the alkali solution is preferably sodium hydroxide solution; the mass concentration of the sodium hydroxide solution is preferably 30 to 50%, more preferably 50%; the ratio of the mass of the crude bisphenol F to the volume of the alkali solution is preferably 2 to 10:1, more preferably 3 to 6:1; the second standing time is preferably 0.5 to 3 hours, more preferably 1 to 2 hours; the filtration is preferably vacuum filtration; the pressure of the vacuum filtration is preferably -0.06 to -0.09 MPa, more preferably -0.08 MPa; the reagent used to adjust the pH value of the filtrate is preferably hydrochloric acid; the mass concentration of the hydrochloric acid is preferably 5 to 20%, more preferably 10 to 15%; the mass ratio of the crystals to toluene is preferably 1 to 4:1, more preferably 2 to 3:1; the dissolving of the crystals in toluene is preferably heating to dissolve; the temperature of the heating to dissolve is preferably The temperature of the crystals is preferably 20 to 80°C, more preferably 40 to 60°C; the time for heating and dissolving is preferably 0.5 to 3 hours, more preferably 1 to 2 hours; the cooling crystallization is preferably performed by dissolving the crystals in toluene and then naturally cooling the resulting solution to room temperature, and then placing the solution in a freezer for cooling; the cooling temperature is preferably -20 to -5°C, more preferably -15 to -8°C; the cooling time is preferably 0.5 to 3 hours, more preferably 1 hour; the drying temperature is preferably 40 to 100°C, more preferably 50 to 80°C; the drying time is preferably 2 to 5 hours, more preferably 5 hours.

[0059] In the present invention, the preparation method of the bisphenol F epoxy resin preferably comprises the following steps:

[0060] Mixing the bisphenol F, epichlorohydrin and a catalyst to carry out an etherification reaction to obtain an etherification reaction system;

[0061] The etherification reaction system is mixed with sodium hydroxide to carry out a ring-closing reaction to obtain a bisphenol F epoxy resin.

[0062] In the present invention, the bisphenol F, epichlorohydrin and catalyst are preferably mixed to obtain a mixed liquid.

[0063] In the present invention, the catalyst is preferably tetrabutylammonium bromide; the mass ratio of bisphenol F to epichlorohydrin is preferably 1:3-10, more preferably 1:5-7; the mass ratio of bisphenol F to tetrabutylammonium bromide is preferably 100-200:1, more preferably 120-160:1.

[0064] In the present invention, the mixing step preferably comprises first mixing bisphenol F and epichlorohydrin, heating with stirring until the bisphenol F dissolves, and then adding the catalyst. In the present invention, the stirring rate is preferably 100-600 rpm, more preferably 200-400 rpm; the heating temperature is preferably 40-80°C, more preferably 50-60°C; and the heating rate to the heating temperature is preferably 2-10°C / min, more preferably 5-8°C / min.

[0065] After obtaining the mixed material liquid, the present invention preferably performs an etherification reaction on the mixed material to obtain an etherification reaction system.

[0066] In the present invention, the temperature of the etherification reaction is preferably 50-70° C., more preferably 70° C.; the time of the etherification reaction is preferably 2-6 h, more preferably 5 h.

[0067] After obtaining the etherification reaction system, the present invention preferably mixes the etherification reaction system with sodium hydroxide to perform a ring-closure reaction to obtain a bisphenol F epoxy resin.

[0068] In the present invention, the ring-closure reaction preferably includes a first ring-closure reaction and a second ring-closure reaction carried out in sequence; the first ring-closure reaction is preferably performed by cooling the etherification reaction system to 60°C and then adding solid sodium hydroxide at a uniform rate; the mass ratio of bisphenol F to solid sodium hydroxide is preferably 1:1-3, more preferably 1:2-3; the rate of adding sodium hydroxide is preferably 1-5 g / 10 min, more preferably 3 g / 10 min; the temperature of the first ring-closure reaction is preferably 40-80°C, more preferably 50-65°C; the time of the first ring-closure reaction is preferably 1-4 h, more preferably 2 h; before the second ring-closure reaction, the present invention preferably concentrates the product obtained from the first ring-closure reaction under reduced pressure to recover epichlorohydrin; the pressure of the reduced pressure concentration is preferably -0.06 to -0.09 MPa, more preferably -0.08 MPa; the temperature of the reduced pressure concentration is preferably 100-180°C, more preferably 120-160°C; the time of the reduced pressure concentration is preferably 1-4 h, more preferably 2-3 h.

[0069] In the present invention, the first ring-closing reaction is carried out under negative pressure to facilitate dehydration and exclude air, and the purpose of the second ring-closing reaction is to reduce hydrolyzable chlorine.

[0070] In the present invention, the second ring-closure reaction is preferably to dissolve the product obtained from the first ring-closure reaction in an organic solvent, and then add sodium hydroxide solution to carry out a second ring-closure reaction. In the present invention, the organic solvent is preferably toluene; the mass ratio of the product obtained from the first ring-closure reaction to the organic solvent is preferably 1 to 4: 1, more preferably 2 to 3: 1; the dissolving of the product obtained from the first ring-closure reaction in an organic solvent is preferably mixing the product obtained from the first ring-closure reaction and the organic solvent, and heating under stirring; the stirring rate is preferably 100 to 600 rpm, more preferably 200 to 400 rpm; the heating temperature is preferably 60 to 100 ° C, more preferably 70 to 90 ° C; the heating time is preferably 0.5 to 3 h, more preferably 1 to 2 h; the mass concentration of the sodium hydroxide solution is preferably 20 to 50%, more preferably 32%; the mass ratio of the product obtained from the first ring-closure reaction to the sodium hydroxide solution is preferably 10 to 20: 1, more preferably 12 to 16: 1. In the present invention, the temperature of the second ring-closure reaction is preferably 60 to 100° C., more preferably 70 to 90° C.; the time of the second ring-closure reaction is preferably 0.2 to 2 h, more preferably 0.5 h.

[0071] In the present invention, the product obtained by the first ring-closing reaction is first dissolved in an organic solvent, and then a sodium hydroxide solution is added to facilitate better dispersion of the resin and improve the reaction effect.

[0072] After the ring-closure reaction, the present invention preferably further comprises: allowing the ring-closure reaction product to stand and then separating the liquids to obtain an organic phase and brine respectively; subjecting the organic phase to reduced pressure distillation to recover the organic solvent and then filtering to obtain a bisphenol F epoxy resin; and mixing the brine with a sodium dihydrogen phosphate solution for washing.

[0073] In the present invention, the standing time is preferably 0.5 to 3 hours, more preferably 1 to 2 hours; the pressure of the reduced pressure distillation is preferably -0.06 to -0.09 MPa, more preferably -0.08 MPa; the temperature of the reduced pressure distillation is preferably 100 to 150° C., more preferably 120 to 135° C.; the time of the reduced pressure distillation is preferably 0.5 to 3 hours, more preferably 1 to 2 hours; the mass concentration of the sodium dihydrogen phosphate solution is preferably 1 to 10%, more preferably 5%; the volume ratio of the brine to the sodium dihydrogen phosphate solution is preferably 1 to 2:1, more preferably 1 to 1.5:1; the number of washing times is preferably 2 to 5 times, more preferably 3 times; and the washing is performed until the filtrate is clear and transparent.

[0074] The technical solutions of the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention, but they should not be understood as limiting the scope of protection of the present invention.

[0075] Example 1

[0076] 100 g of sodium perchlorate solution (mass concentration: 40%) was added to a reactor, 25 g of anhydrous lithium chloride was added, and the mixture was heated at 60° C. for a double decomposition reaction for 2.5 hours to generate lithium perchlorate and sodium chloride. The sodium chloride was removed by filtration, and the filtrate was evaporated and concentrated at 120° C. for 1.5 hours, and cooled and crystallized with ethanol aqueous solution at −10° C. for 2 hours to obtain crude lithium perchlorate. 83 g of the crude lithium perchlorate was dissolved in ethanol, filtered, cooled and crystallized at −10° C. for 2 hours, centrifuged at 10,000 rpm for 15 minutes, and dried at 60° C. for 5 hours to obtain lithium perchlorate.

[0077] Cr2O3, anhydrous ethanol, and glacial acetic acid (mass concentration: 99%) were mixed in a mass ratio of 1:5:5, and magnetically stirred at 300 rpm for 20 minutes. Dilute nitric acid (mass concentration: 20%) was then added, and the pH value of the resulting mixture was adjusted to 3. The mixture was magnetically stirred at 300 rpm for 20 minutes in a 60°C water bath to obtain a Cr2O3 sol.

[0078] 25 mg of LiClO4 was added to 50 mL of a mixed solution of oxalic acid and concentrated hydrochloric acid (the volume ratio of oxalic acid to hydrochloric acid was 1:3, the mass concentration of oxalic acid was 5%, and the mass concentration of hydrochloric acid was 20%), and the mixture was stirred at 300 rpm for 30 min to fully dissolve the LiClO4 to obtain a LiClO4 solution;

[0079] The Cr2O3 sol and LiClO4 solution with a volume ratio of 3:1 were mixed evenly, placed in a reactor lined with polytetrafluoroethylene, compounded at 160°C for 20 hours, cooled to -10°C in a water bath with ethanol water, filtered under negative pressure, washed with ethanol until the filtrate was clear and transparent, and dried at 60°C for 2 hours to obtain a chromium oxide-lithium perchlorate composite catalyst (Cr2O3@LiClO4 composite catalyst with a particle size of 32 nm and a specific surface area of ​​155 m 2 / g, the mass ratio of chromium oxide to lithium perchlorate is 2.5:1, and the particle size of lithium perchlorate is 7.6 nm).

[0080] Application Example 1

[0081] 800g of phenol was added to a 2000mL three-necked flask equipped with an electric stirrer, a thermometer and a reflux condenser, and heated in a 50℃ water bath for 0.5h. After the phenol was fully melted, 246.4g of 85wt.% phosphoric acid and 10g of the Cr2O3@LiClO4 catalyst prepared in Example 1 were stirred at 300rpm to mix the system evenly, and then 66.4g of paraformaldehyde was added at 0.6g / min. The stirring speed was fixed and the condensation reaction was carried out at 45°C for 5h. The temperature was then raised to 80°C at 10°C / min and kept warm for 0.5h. The mixture was then allowed to stand for 0.5h before separation to obtain an inorganic phase and an organic phase (bisphenol F isomer mixture). Most of the phosphoric acid was recovered as an 80% aqueous solution and concentrated at 60°C for 2h to continue to be used as a catalyst. The organic phase was neutralized with a sodium bicarbonate solution (mass concentration of 5%) to a pH of 5.0, and then vacuum dehydrated at 150°C, -0.08MPa, and cooled and crystallized at -10°C. After 2 hours, a white solid crude product was obtained; 412.5g of the crude product was dissolved in 2000mL of sodium hydroxide solution (mass concentration of 50%), allowed to stand for 0.5h, and then filtered under reduced pressure at -0.08MPa to remove insoluble matter. Hydrochloric acid (mass concentration of 10%) was added dropwise to the filtrate to adjust the pH to 4. The product bisphenol F precipitated and was filtered to obtain crystals; 405.6g of the crystals were dissolved in 400mL of toluene at 60°C, heated for 1h, cooled to room temperature, placed in a freezer and cooled at -10°C for 1h, taken out and filtered, dried at 60°C for 5h, and weighed to obtain 367.3g of pure bisphenol F with a yield of 82.97%, calculated by the area normalization method measured by high performance liquid chromatography, wherein the content of 4,4'-dihydroxydiphenylmethane was 93.3%.

[0082] Application Example 2

[0083] The bisphenol F prepared in Application Example 1 was added to a 3000 mL four-necked flask, and then 1689.6 g of epichlorohydrin was added. The mixture was stirred at 300 rpm and heated to 60°C at 5°C / min to fully dissolve the bisphenol F. 2.4 g of catalyst tetrabutylammonium bromide was added and etherified at 70°C for 5 h. The mixture was then cooled to 60°C and 133.7 g of solid sodium hydroxide was added at 3 g / 10 min to carry out a ring-closure reaction for 2 h. After the reaction is completed, the reaction mixture is concentrated under reduced pressure at -0.08 MPa and 100°C for 2 h to recover epichlorohydrin, then the temperature is lowered to 80°C, 500 g of toluene solvent is added, and the mixture is dissolved by stirring at 80°C and 400 rpm. 50 g of sodium hydroxide solution (mass concentration is 32%) is added for a second ring-closure reaction for 0.5 h to further reduce the hydrolyzable chlorine. After standing for 0.5 h, the liquid is separated to obtain a lower brine and an upper organic phase. The lower brine is washed with neutralized water containing sodium dihydrogen phosphate (the mass concentration of sodium dihydrogen phosphate is 5%) (the volume ratio of brine to sodium dihydrogen phosphate solution is 1.5:1), and the washing is repeated 3 times until the filtrate is clear and transparent. The upper organic phase is distilled under reduced pressure at 120°C and -0.08 MPa for 1 h, the solvent toluene is recovered, and the mixture is filtered to obtain 612.7 g of bisphenol F epoxy resin product with a yield of 86.7%.

[0084] Comparative Application Example 1

[0085] 800g of phenol was added to a 2000mL three-necked flask with an electric stirrer, a thermometer and a reflux condenser, and heated in a 50°C water bath for 0.5h. After the phenol was fully melted, 246.4g of 85wt.% phosphoric acid was added and stirred at 300rpm to mix the system. Then 66.4g of paraformaldehyde was added at 0.5g / min. The stirring speed was fixed and the condensation reaction was carried out at 45°C for 5h. The temperature was then raised to 80°C at 10°C / min and kept warm for 0.5h. The inorganic phase and the organic phase (bisphenol F isomer mixture) were then separated. Most of the phosphoric acid was recovered as an 80% aqueous solution and concentrated at 50°C for 2h to continue to be used as a catalyst. The organic phase was neutralized with a sodium bicarbonate solution (mass concentration of 5%) to a pH of 5.0, and then vacuum dehydrated at 150°C, -0.08MPa, and cooled and crystallized at -10°C for 2h to give a white solid crude product. 6.8 g of the crude product was dissolved in a sodium hydroxide solution (mass concentration of 50%), allowed to stand for 0.5 h, and then filtered under reduced pressure at -0.08 MPa to remove insoluble matter. Hydrochloric acid (mass concentration of 10%) was added dropwise to the filtrate to adjust the pH to 4. The product bisphenol F precipitated and was filtered to obtain crystals. 301.6 g of the crystals were then dissolved in 2000 mL of toluene at 60° C., cooled to room temperature, placed in a freezer at -10° C. for 1 h, removed and filtered, and then dried at 70° C. for 5 h. The product was weighed to obtain 258.3 g of pure bisphenol F with a yield of 58.4%. The content of 4,4'-dihydroxydiphenylmethane was 73.3% as calculated by the area normalization method measured by high-performance liquid chromatography.

[0086] Comparative Application Example 2

[0087] The bisphenol F prepared in Comparative Application Example 1 was added to a 3000 mL four-necked flask, and then 1188.2 g of epichlorohydrin was added. The temperature was raised to 60° C. with stirring at 300 rpm to fully dissolve the bisphenol F. 2.4 g of catalyst tetrabutylammonium bromide was added, and the mixture was etherified at 70° C. for 5 h. The temperature was then lowered to 60° C., and 93.8 g of solid sodium hydroxide was added at 3 g / 10 min to carry out a ring-closure reaction for 2 h. After the reaction, the epichlorohydrin was recovered under reduced pressure, and then the temperature was raised to 80° C., toluene solvent was added and stirred to dissolve it, and then 15 g of sodium hydroxide solution (concentration of 32%) was added to carry out a second ring-closure reaction for 0.5 h to further reduce the hydrolyzable chlorine. After standing for 2 h, the liquid was separated to obtain a lower brine layer and an upper organic phase. The lower brine layer was washed with neutralized water containing sodium dihydrogen phosphate (the mass concentration of sodium dihydrogen phosphate was 5%) until the filtrate was clear and transparent. The upper organic phase was taken and the solvent toluene was recovered under reduced pressure at 150° C. and -0.08 MPa, and filtered to obtain 380.5 g of bisphenol F epoxy resin product with a yield of 76.8%.

[0088] Performance Testing

[0089] The properties of the liquid bisphenol F epoxy resin obtained in Example 2 and Comparative Example 2 were tested, and the results are shown in Table 1. Test Method: The viscosity of the liquid bisphenol F epoxy resin was tested in accordance with GB / T 2794-1995 using a rotational viscometer. The epoxy equivalent was determined using the hydrochloric acid-acetone method in accordance with HG2-741-72. The hydrolyzable chlorine content was determined using potentiometric titration.

[0090] Table 1 Performance test results of liquid bisphenol F epoxy resin obtained in Application Example 2 and Comparative Application Example 2

[0091] Serial number Viscosity at 25℃ (Pa.s) Epoxide equivalent (g / eq) Hydrolyzable chlorine content (%) Application Example 1 2.2 171 0.017 Comparative Application Example 2 3 175 0.028

[0092] As can be seen from Table 1, the liquid bisphenol F epoxy resin prepared using the chromium oxide-lithium perchlorate composite catalyst provided by the present invention has a lower viscosity at 25°C and a lower hydrolyzable chlorine content than the liquid bisphenol F epoxy resin prepared without using the chromium oxide-lithium perchlorate composite catalyst.

[0093] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention rather than all the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. Application of a chromium oxide-lithium perchlorate composite catalyst in the preparation of bisphenol F, characterized in that: The chromium oxide-lithium perchlorate composite catalyst consists of lithium perchlorate and chromium oxide wrapping the lithium perchlorate.

2. The use according to claim 1, characterized in that The mass ratio of chromium oxide to lithium perchlorate in the chromium oxide-lithium perchlorate composite catalyst is 2 to 4:1; the particle size of lithium perchlorate in the chromium oxide-lithium perchlorate composite catalyst is 2 to 30 nm; the particle size of the chromium oxide-lithium perchlorate composite catalyst is 10 to 100 nm; the specific surface area of ​​the chromium oxide-lithium perchlorate composite catalyst is 100 to 500 m 2 / g.

3. The use according to claim 1, characterized in that The preparation method of the chromium oxide-lithium perchlorate composite catalyst comprises the following steps: Mixing chromium oxide, an organic solvent and a complexing agent, adjusting the pH value of the resulting mixture to 2-4 to carry out a complexing reaction to obtain a chromium oxide sol; dissolving lithium perchlorate in a mixed solution of oxalic acid and hydrochloric acid to obtain a lithium perchlorate solution; The chromium oxide sol and the lithium perchlorate solution are mixed and heated to obtain a chromium oxide-lithium perchlorate composite catalyst.

4. The use according to claim 3, characterized in that The complexing agent includes glacial acetic acid.

5. The use according to claim 3, characterized in that The mass ratio of the chromium oxide to the complexing agent is 1:5-10.

6. The use according to claim 3 or 4, characterized in that The temperature of the complexation reaction is 30 to 70°C; The complexation reaction time is 10 to 30 minutes.

7. A method for preparing bisphenol F, characterized in that: The following steps are involved: Phenol, paraformaldehyde, phosphoric acid and a chromium oxide-lithium perchlorate composite catalyst are mixed and subjected to a condensation reaction to obtain bisphenol F; The chromium oxide-lithium perchlorate composite catalyst is the chromium oxide-lithium perchlorate composite catalyst used in any one of claims 1 to 6.

8. The preparation method according to claim 7, characterized in that The mass ratio of the phenol to the chromium oxide-lithium perchlorate composite catalyst is 50-100:

1.

9. The preparation method according to claim 7, characterized in that The temperature of the condensation reaction is 35 to 55° C.; the time of the condensation reaction is 1 to 5 hours.