CN115611709A - Synthetic method of 4,4' -dihydroxybiphenyl - Google Patents
Synthetic method of 4,4' -dihydroxybiphenyl Download PDFInfo
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- C07C37/50—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring by reactions decreasing the number of carbon atoms
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Abstract
The invention relates to the technical field of chemical synthesis, and provides a synthetic method of 4,4 '-dihydroxybiphenyl, which comprises the steps of mixing 3,3',5,5 '-tetra-tert-butyl-4,4' -dihydroxybiphenyl, a reaction solvent and an acid catalyst to obtain a reaction system; introducing inert gas into the reaction system for gas stripping, and performing a tert-butyl removal reaction to obtain a reaction liquid and isobutene mixed gas; recrystallizing the reaction solution to obtain 4,4' -dihydroxybiphenyl; the synthesis method provided by the invention can reduce the by-products generated by incomplete removal of the tert-butyl group, improve the reaction rate in the later period, and has the advantage of not blocking pipelines and reactors.
Description
Technical Field
The invention relates to the technical field of chemical synthesis, in particular to a synthetic method of 4,4' -dihydroxybiphenyl.
Background
4,4' -dihydroxybiphenyl is a very important organic compound and an important monomer for preparing liquid crystal materials. The diester liquid crystal synthesized by using 4,4 '-dihydroxybiphenyl as a mesogenic raw material and aromatic acids has the advantages of colorlessness, high anisotropy value, wide liquid crystal phase interval and the like, but the liquid crystal material has high requirements on 4,4' -dihydroxybiphenyl, the purity is lower than 99.5 percent, the mechanical property and the heat resistance of the liquid crystal material are reduced, and high-performance resin cannot be obtained.
Due to the special properties of the liquid crystal material synthesized by using 4,4' -dihydroxybiphenyl as the raw material, the market of the liquid crystal material is rapidly developed, and particularly in recent years, with the development of the technologies of various electronic devices such as computers, mobile phones and the like, a huge market development space is provided for the product. At present, domestic high-purity 4,4 '-dihydroxybiphenyl is in a state of short supply and short demand, and tens of thousands of tons of high-purity 4,4' -dihydroxybiphenyl need to be imported each year for producing liquid crystal materials.
At present, the domestic preparation of 4,4' -dihydroxybiphenyl is mainly carried out by a biphenyl sulfonation alkali fusion method, namely 4,4' -dihydroxybiphenyl is prepared by sulfonating and alkali fusion of biphenyl, but the method needs a large amount of concentrated acid and strong alkali in the reaction process and causes great environmental pollution, and the prepared 4,4' -dihydroxybiphenyl has low purity and cannot be used as a monomer of a liquid crystal material, so that large-scale production is not formed. The domestic demand for high-purity 4,4' -dihydroxybiphenyl is always dependent on import.
The current international preparation method for 4,4' -dihydroxy biphenyl is 2,6-di-tert-butylphenol oxidative coupling dealkylation, namely 2,6-di-tert-butyl biphenol is firstly oxidized and coupled into 3,3',5,5' -tetra-tert-butyl-4,4 ' -dihydroxy biphenyl, and then the tert-butyl is removed to generate 4,4' -dihydroxy biphenyl. In the method, the oxidative coupling reaction of 2,6-di-tert-butylphenol is an exothermic reaction of carbon-carbon coupling, and the step of the butyl removal is a reverse reaction of a friedel-crafts alkylation reaction and is an endothermic reaction. In the step of the butyl removal, along with the increase of the number of the butyl removal, the electron cloud density on a benzene ring is lower and lower, the tert-butyl removal is more and more difficult, the reaction is difficult to be carried out completely, and the required conditions are more severe, so that how to carry out the butyl removal reaction completely is a difficult point of the process technology. The process was studied internationally since the 80's of the 19 th century, and the current patents US4205187, US4891453 and US5099076 all studied the process route as a whole.
In order to solve the technical problem of incomplete de-butyl reaction, the patent US6794548 discloses a method for promoting the reaction by using monoalkyl phenols as a solvent and connecting a plurality of reactors in series. The method has the problems that alkylphenol is used as a solvent, the alkyl on the alkylphenol solvent is partially removed while the reactant is subjected to tert-butyl removal, various byproducts are generated, and various phenols are mixed together and are difficult to separate. The patent US5324828 discloses a method of using substituted aromatic compounds (such as chlorobenzene, toluene, diethylbenzene, decalin, etc.) as solvents, connecting a plurality of reactors in series, and adding catalysts in each reactor in a segmented manner to promote the reaction. Although the method can solve the problem that the reaction rate is slow in the later stage of the reaction, the method has the problems that the solubility of the product 4,4 '-dihydroxybiphenyl in the solvent alkylbenzene is very low, and the generated 4,4' -dihydroxybiphenyl is accumulated to block pipelines or equipment.
Disclosure of Invention
In view of the above, the invention provides a method for synthesizing 4,4' -dihydroxybiphenyl; the synthesis method provided by the invention can reduce the byproducts generated by incomplete removal of the tert-butyl, improve the reaction rate in the later period, and does not block a transfer pipeline and a reactor.
In order to achieve the above object, the present invention provides the following technical solutions:
a method for synthesizing 4,4' -dihydroxybiphenyl comprises the following steps:
mixing 3,3',5,5' -4,4' -dihydroxy biphenyl, a reaction solvent and an acid catalyst to obtain a reaction system;
introducing inert gas into the reaction system for gas stripping, and performing a tert-butyl removal reaction to obtain a reaction liquid and isobutene mixed gas;
recrystallizing the reaction solution to obtain 4,4' -dihydroxybiphenyl;
the reaction solvent includes one or more of N, N-dimethylformamide, dimethylsulfoxide and γ -butyrolactone.
Preferably, the mass ratio of 3,3',5,5' -4,4' -dihydroxydiphenyl to reaction solvent to acid catalyst is 1:0.5 to 10:0.005 to 0.1.
Preferably, the acid catalyst comprises a protic acid and/or a lewis acid.
Preferably, the protonic acid is one or more of toluene sulfonic acid, dodecyl benzene sulfonic acid and terephthalic acid.
Preferably, the lewis acid is anhydrous aluminum trichloride.
Preferably, the temperature of the tert-butyl removal reaction is 130 to 220 ℃.
Preferably, the inert gas is nitrogen.
Preferably, the inert gas is introduced in an amount of 10 to 25NM 3 /h/m 3 And (3) reaction liquid.
Preferably, the inert gas is introduced in two stages, wherein the amount of the inert gas introduced in the first stage is 0 to 0.01 percent/min of the amount of 3,3',5,5' -tetra-tert-butyl-4,4 ' -dihydroxybiphenyl substances; the amount of the substance to be introduced in the second stage is 3,3',5,5' -tetra-tert-butyl-4,4 ' -dihydroxybiphenyl 0.5 to 2%/min.
Preferably, the first-stage reaction pressure is 0.1 to 0.4MPaG, and the second-stage reaction pressure is 0.2 to 0.6MPaG.
Preferably, the reaction system further comprises a temperature rise stage before the tert-butyl removal reaction, and the temperature rise rate is 1 to 10 ℃/min.
Preferably, the recrystallization uses xylene as a solvent;
preferably, the mass ratio of the xylene to 3,3',5,5' -4,4' -dihydroxybiphenyl is 1 to 10:1.
has the advantages that:
the invention provides a method for synthesizing 4,4' -dihydroxybiphenyl, which comprises the following steps: mixing 3,3',5,5' -4,4' -dihydroxy biphenyl, a reaction solvent and an acid catalyst to obtain a reaction system; introducing inert gas into the reaction system to carry out gas stripping and tert-butyl removal reaction to obtain a reaction liquid and isobutene mixed gas; recrystallizing the reaction solution to obtain 4,4' -dihydroxybiphenyl. The reaction solvent includes one or more of N, N-dimethylformamide, dimethylsulfoxide and γ -butyrolactone.
According to the invention, inert gas is introduced for gas stripping during the tert-butyl removal reaction, a flowing gas flow and a pressure environment are formed in the reaction system, isobutene can be discharged out of the reaction system in the gas stripping process, the reaction chemical equilibrium is promoted to be carried out towards the positive direction, the tert-butyl removal is more thorough, the reaction rate in the later stage is improved, and the overall reaction time is shortened; the introduction of inert gas can also reduce the generation of side reaction and improve the yield and purity of the product. One or more of N, N-dimethylformamide, dimethyl sulfoxide and gamma-butyrolactone are selected as reaction solvents, compared with alkylbenzene and N-alkane, the solubility of 4,4' -dihydroxybiphenyl in DMF, DMSO and gamma-butyrolactone is higher, tert-butyl is thoroughly removed under the action of gas stripping, and products are not easy to accumulate under the condition of accelerating the later reaction rate, so that the problem of pipeline or reactor blockage during product transfer is solved.
The results of the examples and the comparative examples show that the method for synthesizing 4,4 '-dihydroxybiphenyl can effectively eliminate the by-product of incomplete removal of tert-butyl, no crystal is precipitated in advance in the reaction process, the molar yield of 4,4' -dihydroxybiphenyl reaches 97.4%, and the product purity reaches 99.5%.
Drawings
FIG. 1 is a liquid chromatogram of the product prepared in example 1 of the present invention;
FIG. 2 is a mass spectrum of the product of example 1 of the present invention;
FIG. 3 is a comparison of IR spectra of example 1 of the present invention and a sample of standard 4,4' -dihydroxybiphenyl;
FIG. 4 is a liquid chromatogram of the product prepared in comparative example 3;
FIG. 5 is a mass spectrum of the production process of comparative example 3 with three tert-butyl intermediate byproducts removed;
FIG. 6 is a mass spectrum of two tert-butyl intermediate byproducts removed during the preparation of comparative example 3.
Detailed Description
The invention provides a method for synthesizing 4,4' -dihydroxybiphenyl, which comprises the following steps:
mixing 3,3',5,5' -tetra-tert-butyl-4,4 ' -dihydroxy biphenyl, a reaction solvent and an acid catalyst to obtain a reaction system;
introducing inert gas into the reaction system for gas stripping, and performing a tert-butyl removal reaction to obtain a reaction liquid and isobutene mixed gas;
recrystallizing the reaction solution to obtain 4,4' -dihydroxybiphenyl.
Mixing 3,3',5,5' -tetra-tert-butyl-4,4 ' -dihydroxy biphenyl, a reaction solvent and an acid catalyst to obtain a reaction system;
the invention has no special limitation on the mixing sequence of 3,3',5,5' -tetra-tert-butyl-4,4 ' -dihydroxydiphenyl, reaction solvent and acid catalyst; in the present invention, the mixing is preferably performed by first mixing 3,3',5,5' -tetra-tert-butyl-4,4 ' -dihydroxybiphenyl and a reaction solvent, and then adding an acid catalyst for second mixing; the preferable mixing sequence in the invention mainly considers that part of acid catalysts, such as sulfonic acid catalysts, are high-hygroscopicity solids and poor in fluidity, and the solid catalysts must be added into a reaction system very quickly, so that the catalysts can play a catalytic role after being dissolved, and the catalytic effect is improved.
In the invention, the mass ratio of 3,3',5,5' -tetra-tert-butyl-4,4 ' -dihydroxybiphenyl, reaction solvent and acid catalyst in the reaction system is preferably 1:0.5 to 10:0.005 to 0.1; more preferably 1:1~5:0.01 to 0.06; the dosage of the acid catalyst is preferably 0.01 to 0.06 of 3,3',5,5' -tetra-tert-butyl 4,4 '-dihydroxybiphenyl, and the dosage of 3,3',5,5 '-tetra-tert-butyl-4,4' -dihydroxybiphenyl and the acid catalyst are adjusted to be 1:0.01 to 0.06, the influence degree of the catalyst on the quality and color of the reaction product can be reduced, and the catalytic efficiency can also reach the expected effect.
In the invention, the 3,3',5,5' -tetra-tert-butyl-4,4 ' -dihydroxydiphenyl has the purity of 96% and the melting range of 185-189 ℃; the raw material source of 3,3',5,5' -tetra-tert-butyl-4,4 ' -dihydroxybiphenyl in the present invention is not particularly limited, and commercially available products which are conventional in the art can be used.
In the present invention, the reaction solvent preferably includes one or more of N, N-dimethylformamide (abbreviated as DMF), dimethylsulfoxide (abbreviated as DMSO), and γ -butyrolactone; the selection of the reaction solvent in the invention is to consider that the boiling point of the reaction solvent is selected to be higher than the initial reaction temperature of the de-butyl; meanwhile, after the inert gas is introduced for gas stripping, the removal of the butyl is more thorough, the reaction rate is accelerated, the product amount is increased rapidly, and if the reaction product is not dissolved and transferred in time, the product is separated out in advance in the reactor, so that the accumulation phenomenon is caused. One or more of N, N-dimethylformamide, dimethyl sulfoxide and gamma-butyrolactone are selected as reaction solvents, and compared with alkylbenzene, normal alkane and the like, the solvent has higher solubility to the product, so that the problem of pipeline and reactor blockage caused by the product precipitation in advance in the transfer process can be avoided; compared with the unfavorable situations that a plurality of byproducts are generated and the product is not easy to separate when monoalkylphenols are used as solvents, the selection of the reaction solvent is combined with the stripping action of the inert gas, the generation of most of the byproducts and the intermediate products can be reduced under the oxygen-free environment, the stripping effect can promote the forward reaction, and the product yield and the product purity are obviously improved.
In the present invention, the acid catalyst preferably comprises a protic acid and/or a lewis acid; in the invention, the protonic acid preferably comprises one or more of sulfuric acid, sulfonic acid compounds, hydrogen sulfate, selenic acid, telluric acid, nitric acid, phosphoric acid, dihydrogen phosphate, bis (trifluoromethanesulfonyl) imide and fluorosulfonyl imide; further preferred in embodiments of the present invention are one or more of toluene sulfonic acid, dodecylbenzene sulfonic acid and terephthalic acid; more preferred in embodiments of the present invention is toluene sulfonic acid.
In the present invention, the lewis acid preferably includes one or more of anhydrous magnesium chloride, anhydrous aluminum chloride, zinc chloride, titanium tetrachloride and butyl titanate, and is preferably anhydrous aluminum trichloride in the embodiment of the present invention.
After a reaction system is obtained, introducing inert gas into the reaction system for gas stripping, and performing a tert-butyl removal reaction to obtain a reaction liquid and isobutene mixed gas;
in the invention, the tert-butyl removal reaction temperature is preferably 130 to 220 ℃, and more preferably 160 to 190 ℃; in the present invention, the tert-butyl removal reaction is preferably carried out in a reaction kettle; the preferred range of the reaction temperature for removing the tert-butyl is that the reaction rate is slow due to the low temperature, the tert-butyl cannot be completely removed, and the yield and the purity of the product are reduced; and the side reaction is aggravated when the reaction temperature is too high, and the quality of the product is also influenced by the acid catalyst at high temperature, so that the quality and the yield of the product are reduced.
In the present invention, the reaction time for tert-butyl removal is preferably 1 to 12h, and more preferably 4 to 8h;
in the present invention, the amount of the inert gas to be introduced may be selected depending on the volume of the reaction solution, and is preferably 10 to 25nm 3 /h/m 3 The reaction solution is more preferably 15 to 20nm 3 /h/m 3 And (3) reaction liquid. In the present invention, the inert gas preferably includes one or more of nitrogen, helium and argon, and is further preferably nitrogen; in the invention, the gas stripping is realized by controlling the introduction amount of inert gas to form a flowing environment.
In the present invention, the inert gas is preferably introduced in two stages, the amount of the introduced gas being gradually increased from the first stage to the second stage. In the invention, the amount of the inert gas introduced in the first stage is preferably 0 to 0.01 percent/min of the amount of 3,3',5,5' -tetra-tert-butyl-4,4 ' -dihydroxybiphenyl substance; in the invention, the amount of the inert gas introduced in the second stage is preferably 0.5 to 2%/min, and more preferably 1 to 1.5%/min of the substance of the reactant 3,3',5,5' -tetra-tert-butyl-4,4 ' -dihydroxybiphenyl; in the process of the tert-butyl removal reaction, the introduction amount of inert gas is gradually increased along with the reaction time, so that the spontaneous reaction is firstly carried out in the early stage of the tert-butyl removal reaction, the reaction rate is high at the moment, the reaction can be carried out by depending on the driving force of the reaction, the introduction of the inert gas enables the reaction system to form a gas stripping effect, the introduction amount of the inert gas is gradually increased along with the gradual reduction of the reaction rate and the driving force in the later stage, the gas stripping effect is increased, the isobutene is accelerated to be discharged out of the reaction system, the forward progress of the reaction is promoted, the removal of a plurality of tert-butyl groups is promoted to be more thorough, the reaction rate in the later stage is accelerated, intermediate byproducts of di-tert-butyl and mono-tert-butyl are reduced, and the purity and the yield of the product are also improved; the flow rate of the inert gas can not exceed the limit, so that the volatile steam quantity of the solvent is easily brought out of the reaction system.
In the invention, the first-stage reaction pressure is preferably 0.1 to 0.4MPaG; the second-stage reaction pressure is preferably 0.2 to 0.6MPaG; in the present invention, the pressure of the isobutyl reaction removed by gas stripping is also a crucial influencing factor, which is also an unexpected finding of the present inventors; generally speaking, the de-isobutene reaction is a volume increasing process, and reducing the pressure is beneficial to complete reaction, but the inventor finds that when the de-isobutene speed is reduced in the second stage of reaction, a certain reaction pressure is increased, and the reaction yield can be improved. This is because, at higher reaction pressures, the amount of solvent vaporized is reduced, which not only reduces the external heat demand, but also reduces the viscosity of the system, the nitrogen bubbles become thinner and collapse faster, and the rate of generated bubbles increases, thereby increasing the rate of isobutylene desorption from the solution.
In the invention, the reaction time of the first stage is preferably 2 to 4h; in the present invention, the reaction time in the second stage is preferably 4 to 6 hours.
In the invention, the reaction system preferably further comprises a temperature rise stage before the tert-butyl removal reaction, wherein the temperature rise rate of the temperature rise stage is preferably 1 to 10 ℃/min, and more preferably 3~5 ℃/min; the invention can not continuously introduce inert gas in the temperature rising stage.
According to the invention, preferably, inert gas is introduced to replace the air in the reaction kettle before the temperature rise stage; the inert gas is introduced before the temperature rise stage so as to exhaust the air in the reaction kettle, and the side reaction caused by the existence of the air in the temperature rise process is reduced. After the temperature rise stage is finished, the pressure of a reaction system is increased to 1 to 1.4Mpa due to the existence of nitrogen and isobutene generated by the initial reaction in a reaction kettle, inert gas and isobutene generated by the initial reaction are discharged at the time, pressure is relieved, the pressure is reduced to 0.1 to 0.4Mpa, and then the tert-butyl removal reaction is continued.
The invention can generate isobutene mixed gas besides reaction liquid by carrying out the tert-butyl removal reaction; in the invention, isobutene gas and evaporated solvent steam in the mixed gas can be discharged out of the reaction system along with the flow of the inert gas, then the reaction system enters a first condensation process to separate the reaction solvent, and the condensed reaction solvent can circularly enter the reaction system again; and the rest inert gas and isobutene mixed gas enters a second condensation process, and isobutene is separated and collected.
In the present invention, the condensation temperature in the first condensation step is 50 to 70 ℃, more preferably 60 ℃, and the condensation temperature in the second condensation step is-10 to 0 ℃, more preferably-4 ℃.
After the reaction liquid is obtained, the reaction liquid is recrystallized to obtain 4,4-dihydroxybiphenyl.
In the invention, the reaction solution is preferably cooled to below 150 ℃ and then recrystallized; in the present invention, the recrystallization is preferably performed in a crystallization kettle;
in the present invention, the recrystallization is preferably xylene as a solvent, and the mass ratio of the xylene to the 3,3',5,5' -tetra-tert-butyl-4,4 ' -dihydroxybiphenyl is preferably 1 to 10:1, more preferably 3~5:1; in the present invention, the xylene is preferably one or more of o-xylene, m-xylene and p-xylene.
In the invention, the recrystallization is preferably carried out by cooling from 150 ℃ to room temperature for crystallization; in the present invention, the recrystallization preferably further includes filtration, drying and constant weight processes; the invention has no special requirements on the processes of filtration, drying and constant weight, and adopts the conventional technical scheme of filtration, drying and constant weight in the field. With the reduction of the temperature, the product 4,4 '-dihydroxybiphenyl is separated out in the form of crystals, and refined 4,4' -dihydroxybiphenyl is obtained after filtration, drying and constant weight.
The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention.
Example 1
500g of 3,3',5,5' -tetra-tert-butyl-4,4 ' -dihydroxybiphenyl (light yellow crystals, the product content is 96 percent, the melting range is 185-189 ℃), 1000g of DMF and 5g of p-toluenesulfonic acid are put into a reaction kettle to be mixed, nitrogen is used for replacing air in the reaction kettle, meanwhile, the temperature of the reaction kettle is increased to 180 ℃ at 3 ℃/min, the pressure in the reaction kettle is increased to 1.4MPa, an air outlet valve and a back pressure valve are opened to release pressure, the pressure in the reaction kettle is adjusted to 0.4MPa, a large amount of isobutene is discharged in the initial stage of the reaction, after the reaction is carried out for 2 hours, the amount of isobutene is obviously reduced, nitrogen is introduced into the system again for stripping, the nitrogen flow is 1L/min, after the reaction is carried out for 4 hours, the nitrogen flow is adjusted to 1.5L/min, and the reaction pressure is adjusted to 0.5MPa. And (3) feeding the solvent, the isobutene and the inert gas discharged from the reaction system into a condenser, controlling the temperature of the primary condenser to be 60 ℃, pumping the condensed solvent into the reaction system again by using a solvent circulating pump, controlling the temperature of the secondary condenser to be-4 ℃, and collecting the isobutene.
After the reaction is carried out for 6 hours, stopping the reaction, reducing the temperature in the reaction kettle to 150 ℃, transferring the liquid material (no solid is separated out at this time) in the reaction kettle to a crystallization kettle through a pipeline, adding 1000g of p-xylene into the crystallization kettle, gradually reducing the temperature to room temperature, separating 4,4 '-dihydroxybiphenyl in a crystal form in the process, filtering, drying to constant weight to obtain refined 4,4' -dihydroxybiphenyl mass 205 g, and detecting the product purity by using a high performance liquid chromatography external standard method: the product is white crystal, has glittering and translucent color, the purity of the product is 99.5 percent, and the molar yield of the product is 93.3 percent.
And (3) testing the purity of the obtained product by high performance liquid chromatography under the following test conditions: and (3) chromatographic column: c18 25cm × 4.6mm × 5um, column temperature: 35 ℃; detector wavelength: 254nm, mobile phase: acetonitrile: water (0.1% phosphoric acid) =65 flow: 1.0ml/min, sample size: 5ul; the product has no miscellaneous peak (shown in figure 1) on a high performance liquid chromatogram, the product is 4,4' -dihydroxybiphenyl (shown in figure 2) detected by mass spectrum, the infrared spectrum contrast chart of the product and a standard 4,4' -dihydroxybiphenyl sample is shown in figure 3, the infrared spectrum chart of the product is basically consistent with that of a 4,4' -dihydroxybiphenyl standard product, and the infrared spectrum chart of the product is 3385cm -1 Is the stretching vibration peak of two phenolic hydroxyl groups, 3034.5cm -1 Is the stretching vibration peak of C-H on the benzene ring, 1610.5cm -1 ,1591.3cm -1 ，1497.3cm -1 Is the stretching vibration of the benzene ring, 1244.5cm -1 Is the stretching vibration of C-O bond, 820.2cm -1 Is the out-of-plane bending vibration peak of C-H substituted by para-aryl. The melting range of the product is 284-288 ℃, which is basically consistent with the purchasing standard of Merlin.
Example 2
500g of 3,3',5,5' -tetra-tert-butyl-4,4 ' -dihydroxybiphenyl (light yellow crystal, product content 96%, melting range 185-189 ℃), 1500g of DMF, and 5g of p-toluenesulfonic acid are put into a reaction kettle to be mixed, high-purity nitrogen is used for replacing air in the kettle, the reaction kettle is heated to 160 ℃ at 3 ℃/min, the pressure in the kettle is increased to 1.4MPa, a gas outlet valve and a back pressure valve are opened for pressure relief, the pressure in the kettle is adjusted to 0.4MPa, a large amount of isobutene is discharged at the initial stage of the reaction, the amount of isobutene is obviously reduced after the reaction is carried out for 2h, nitrogen is introduced into the system again, the nitrogen flow is 1L/min, the nitrogen flow is adjusted to 2L/min after the reaction is carried out for 4h, and the reaction pressure is adjusted to 0.6MPa. And (3) feeding the solvent, the isobutene and the inert gas discharged from the reaction system into a condenser, controlling the temperature of a primary condenser to be 60 ℃, pumping the condensed solvent into the reaction system again by using a solvent circulating pump, controlling the temperature of a secondary condenser to be-4 ℃, and collecting the isobutene.
After the reaction is carried out for 6 hours, the reaction is stopped, the temperature of the reaction kettle is reduced to 150 ℃, then the liquid material (without solid precipitation) in the reaction kettle is transferred to a crystallization kettle through a pipeline, 1000g of p-xylene is added into the crystallization kettle and is gradually reduced to room temperature, in the process, 4,4 '-dihydroxybiphenyl is precipitated in a crystal form, the obtained product is 4,4' -dihydroxybiphenyl with the mass of 198 g through filtration and drying until the weight is constant, and the purity is measured by using a high performance liquid chromatography external standard method (the test conditions refer to example 1), so that the product is white crystal, the product purity is 99%, and the molar yield of the product is 90.1%.
Example 3
500g of 3,3',5,5' -tetra-tert-butyl-4,4 ' -dihydroxybiphenyl (light yellow crystal, product content of 96%, melting range of 185-189 ℃), 1000g of DMSO, 5g of p-toluenesulfonic acid are put into a reaction kettle for mixing, high-purity nitrogen is used for replacing air in the kettle, the temperature of the reaction kettle is increased to 190 ℃ at 5 ℃/min, the pressure in the kettle is increased to 1.4MPa, an air outlet valve and a back pressure valve are opened for pressure relief, the pressure in the kettle is adjusted to 0.4MPa, a large amount of isobutene is discharged at the initial stage of the reaction, nitrogen is not used for stripping, the amount of isobutene is obviously reduced after the reaction is carried out for 2 hours, nitrogen is introduced into the system again, the nitrogen flow is 1.5L/min, the nitrogen flow is adjusted to 2L/min after the reaction is carried out for 4 hours, and the reaction pressure is 0.6MPa.
And (3) feeding the solvent, the isobutene and the inert gas discharged from the reaction system into a condenser, controlling the temperature of a primary condenser to be 60 ℃, pumping the condensed solvent into the reaction system again by using a solvent circulating pump, controlling the temperature of a secondary condenser to be-4 ℃, and collecting the isobutene.
After the reaction is carried out for 6 hours, the reaction is stopped, the temperature of the reaction kettle is reduced to 150 ℃, then the liquid material (without solid precipitation) in the reaction kettle is transferred to a crystallization kettle through a pipeline, 1000g of p-xylene is added into the crystallization kettle and is gradually reduced to room temperature, in the process, 4,4 '-dihydroxybiphenyl is precipitated in a crystal form, the obtained product is 4,4' -dihydroxybiphenyl with the mass of 212 g through filtration and drying to constant weight, the purity is measured by using a high performance liquid chromatography external standard method (the test conditions refer to example 1), the product is white crystal, the product purity is 99%, and the molar yield of the product is 96.5%.
Example 4
500g of 3,3',5,5' -tetra-tert-butyl-4,4 ' -dihydroxybiphenyl (light yellow crystal, product content 96%, melting range 185-189 ℃), 1000g of DMSO, 5g of p-toluenesulfonic acid are put into a reaction kettle for mixing, high-purity nitrogen is used for replacing air in the kettle, the temperature of the reaction kettle is increased to 180 ℃ at 3 ℃/min, the pressure in the kettle is increased to 1.0MPa, an air outlet valve and a back pressure valve are opened for pressure relief, the pressure in the kettle is adjusted to 0.2MPa, a large amount of isobutene is discharged at the initial stage of the reaction, nitrogen is not used for stripping, the amount of isobutene is obviously reduced after the reaction is carried out for 2 hours, nitrogen is introduced into the system again, the flow of nitrogen is 1.5L/min, the flow of nitrogen is adjusted to 2L/min after the reaction is carried out for 4 hours, and the reaction pressure is 0.6MPa.
And (3) feeding the solvent, the isobutene and the inert gas discharged from the reaction system into a condenser, controlling the temperature of the primary condenser to be 60 ℃, pumping the condensed solvent into the reaction system again by using a solvent circulating pump, controlling the temperature of the secondary condenser to be-4 ℃, and collecting the isobutene.
After the reaction is carried out for 8 hours, the reaction is stopped, after the temperature of the reaction kettle is reduced to 150 ℃, liquid materials (without solid precipitation) in the reaction kettle are transferred to a crystallization kettle through a pipeline, 1000g of paraxylene is added into the crystallization kettle, 4,4' -dihydroxybiphenyl is precipitated in a crystal form and is gradually reduced to room temperature, 4,4' -dihydroxybiphenyl is precipitated in a crystal form in the process, and the crystal form is filtered and dried to constant weight to obtain a refined product 4,4' -dihydroxybiphenyl with the mass of 210 g, the purity is measured by using a high performance liquid chromatography external standard method (the test condition refers to example 1), the product is white crystals, the product purity is 98.5%, and the molar yield of the product is 95.1%.
Example 5
500g of 3,3',5,5' -tetra-tert-butyl-4,4 ' -dihydroxybiphenyl (light yellow crystal, product content of 96 percent and melting range of 185-189 ℃) is put into a reaction kettle for mixing, 1000g of gamma-butyrolactone and 5g of p-toluenesulfonic acid are put into the reaction kettle for replacing air in the kettle by high-purity nitrogen, meanwhile, the reaction kettle is heated to 220 ℃ at 10 ℃/min, an air outlet valve is opened for starting reaction, a large amount of isobutene is discharged in the initial stage of the reaction, the nitrogen is not used for stripping, after the reaction is carried out for 2h, the amount of the isobutene is obviously reduced, nitrogen is introduced into the system again, the nitrogen flow is 1.5L/min, after the reaction is carried out for 4h, the nitrogen flow is adjusted to 2L/min, and the reaction pressure is 0.6MPa. And (3) feeding the solvent, the isobutene and the inert gas discharged from the reaction system into a condenser, controlling the temperature of the primary condenser to be 60 ℃, pumping the condensed solvent into the reaction system again by using a solvent circulating pump, controlling the temperature of the secondary condenser to be-4 ℃, and collecting the isobutene.
After the reaction is carried out for 6 hours, the reaction is stopped, after the temperature of the reaction kettle is reduced to 150 ℃, liquid materials (without solid precipitation) in the reaction kettle are transferred to a crystallization kettle through a pipeline, 1000g of p-xylene is added into the crystallization kettle, 4,4' -dihydroxybiphenyl is precipitated in a crystal form and is gradually reduced to room temperature, in the process, 4,4' -dihydroxybiphenyl is precipitated in a crystal form, the mixture is filtered and dried to constant weight, the mass of 4,4' -dihydroxybiphenyl is 215 g, the purity is measured by using a high performance liquid chromatography external standard method (the test conditions refer to example 1), the product is white crystal, the product purity is 98.5%, and the product purity is reduced by considering the influence of other byproducts of the acid catalyst under the high-temperature condition of 220 ℃, and the molar yield of the product is 97.4%.
Comparative example 1 Diethylbenzene was used as solvent (solvent used in the example of patent US 5324828)
500g of 3,3',5,5' -tetra-tert-butyl-4,4 ' -dihydroxybiphenyl (light yellow crystal, product content 96%, melting range 185-189 ℃), 1000g of diethylbenzene and 5g of p-toluenesulfonic acid are put into a reaction kettle for mixing, nitrogen is used for replacing air in the reaction kettle, the temperature of the reaction kettle is increased to 180 ℃ at 5 ℃/min, the pressure in the reaction kettle is increased to 1.4MPa, a gas outlet valve and a back pressure valve are opened for pressure relief, the pressure in the reaction kettle is adjusted to 0.4MPa, a large amount of isobutene is discharged at the initial stage of the reaction, the amount of isobutene is obviously reduced after the reaction is carried out for 2h, nitrogen is introduced into the system again for stripping, the flow of nitrogen is 1L/min, the flow of nitrogen is adjusted to 1.5L/min after the reaction is carried out for 4h, and the reaction pressure is adjusted to 0.5MPa.
And (3) feeding the solvent, the isobutene and the inert gas discharged from the reaction system into a condenser, controlling the temperature of the primary condenser to be 60 ℃, pumping the condensed solvent into the reaction system again by using a solvent circulating pump, controlling the temperature of the secondary condenser to be-4 ℃, and collecting the isobutene.
After the reaction is carried out for 6 hours, the reaction is stopped, after the temperature of the reaction kettle is reduced to 150 ℃, a large amount of 4,4 '-dihydroxybiphenyl solid is separated out in the reaction kettle, 4,4' -dihydroxybiphenyl solid is separated out in a pipeline for transferring reaction liquid, and a discharge valve and a pipeline at the bottom of the reaction are blocked.
The products in the reaction kettle and the pipeline were collected, and 195g of solid product (part of the solid product was adhered to the wall of the reactor and the wall of the pipeline, causing loss) was collected, and the purity was measured by the high performance liquid chromatography external standard method (the test conditions refer to example 1), and the product was white crystals, and the content of 4,4' -dihydroxybiphenyl in the solid product was 98%, and the molar yield was 85.8%.
Comparative example 2
Reaction was carried out using a 300ml autoclave with sight glass to observe the time for the initial precipitation of 4,4' -dihydroxybiphenyl when diethylbenzene was used as the solvent
50g of 3,3',5,5' -tetra-tert-butyl-4,4 ' -dihydroxybiphenyl (light yellow crystal, product content 96%, melting range 185-189 ℃), 100g of diethylbenzene and 0.5g of p-toluenesulfonic acid are mixed and then put into a 300ml high-pressure autoclave with a sight glass, high-purity nitrogen is used for replacing air in the autoclave, the temperature is increased to 180 ℃, the pressure in the autoclave is increased to 1.4Mpa, an air outlet valve and a back pressure valve are opened for pressure relief, the pressure in the autoclave is adjusted to 0.4Mpa, a large amount of isobutene is discharged in the initial reaction stage, the amount of isobutene is obviously reduced after the reaction is carried out for 2h, nitrogen is introduced into the system again, the nitrogen flow is 1.5L/min, the nitrogen flow is adjusted to 2L/min after the reaction is carried out for 4h, and the reaction pressure is adjusted to 0.6Mpa. And (3) feeding the solvent, the isobutene and the inert gas discharged from the reaction system into a condenser, controlling the temperature of the primary condenser to be 60 ℃, pumping the condensed solvent into the reaction system again by using a solvent circulating pump, controlling the temperature of the secondary condenser to be-4 ℃, and collecting the isobutene.
When the reaction is carried out for 5 hours, the obvious separation of solids in the system is observed, and the solid content in the system is increased along with the reaction; after the reaction is carried out for 6 hours, the reaction is stopped, the temperature of the reaction kettle is reduced to 150 ℃, the high-pressure kettle is opened, and a large amount of 4,4' -dihydroxybiphenyl solid is separated out in the reaction kettle. It is shown that 4,4' -dihydroxybiphenyl begins to be precipitated in the early stage of the reaction, but not in the process of temperature reduction.
It can be understood from the comparative experiment between example 1 and comparative examples 1 and 2 that, when substituted aromatic compounds such as diethylbenzene are used as the reaction solvent, 4,4' -dihydroxybiphenyl, which is a product, has low solubility in the alkylbenzene solvents, is precipitated during the reaction, resulting in the blockage of the pipeline and reactor by the product.
Comparative example 3 gas stripping without nitrogen
500g of 3,3',5,5' -tetra-tert-butyl-4,4 ' -dihydroxybiphenyl (light yellow crystal, product content 96%, melting range 185-189 ℃), 1000g of DMF,5g of p-toluenesulfonic acid are put into a reaction kettle, high-purity nitrogen is used for replacing air in the kettle, the temperature is increased to 180 ℃, the pressure in the kettle is adjusted to 0.4Mpa, only nitrogen is filled as protective gas in the reaction process, and the nitrogen does not generate flowing and stripping effects.
After the tetrabutyl is subjected to 6 hours, the reaction is stopped, the temperature of the reaction kettle is reduced to 150 ℃, the materials in the reaction kettle are transferred to a crystallization kettle, 1000g of p-xylene is added into the crystallization kettle, 4,4 '-dihydroxybiphenyl is separated out in a crystal form, the temperature is reduced to room temperature, the filtration and the drying are carried out until the weight is constant, the mass of the solid product is 190g, the purity is measured by using a high performance liquid chromatography external standard method (the test condition refers to example 1), the product is white crystals doped with a small amount of white powder, the content of 4,4' -dihydroxybiphenyl in the solid product is 80%, and the molar yield is 70%.
The liquid chromatogram of the product obtained in the comparative example is shown in FIG. 4, the main byproducts are products with incomplete tert-butyl removal, and mainly intermediate byproducts with tri-tert-butyl removal and di-tert-butyl removal, wherein the mass spectrometric detection result of the intermediate byproducts with tri-tert-butyl removal is shown in FIG. 5, and the mass spectrometric detection result of the intermediate byproducts with di-tert-butyl removal is shown in FIG. 6.
The comparison result between example 1 and comparative example 3 shows that, on the premise of other equivalent reaction conditions, if the reaction is carried out in a nitrogen atmosphere only, partial side reaction can be eliminated, but the intermediate product with incomplete tert-butyl removal cannot be eliminated, and the nitrogen is introduced to form a stripping effect, so that the tert-butyl removal can be promoted completely, and the product yield and purity can be improved.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and amendments can be made without departing from the principle of the present invention, and these modifications and amendments should also be considered as the protection scope of the present invention.
Claims (10)
1. A method for synthesizing 4,4' -dihydroxybiphenyl comprises the following steps:
mixing 3,3',5,5' -4,4' -dihydroxy biphenyl, a reaction solvent and an acid catalyst to obtain a reaction system;
introducing inert gas into the reaction system for gas stripping, and performing a tert-butyl removal reaction to obtain a reaction liquid and isobutene mixed gas;
recrystallizing the reaction solution to obtain 4,4' -dihydroxybiphenyl;
the reaction solvent includes one or more of N, N-dimethylformamide, dimethylsulfoxide and γ -butyrolactone.
2. The method of synthesis according to claim 1, wherein the mass ratio of 3,3',5,5' -4,4' -dihydroxybiphenyl, reaction solvent and acid catalyst is 1:0.5 to 10:0.005 to 0.1.
3. The synthesis method of claim 1, wherein the acid catalyst comprises a protic acid and/or a lewis acid.
4. The method of claim 3, wherein the protic acid is one or more of toluene sulfonic acid, dodecyl benzene sulfonic acid, and terephthalic acid.
5. The method of claim 3, wherein the Lewis acid is anhydrous aluminum trichloride.
6. The synthesis method according to claim 1, wherein the temperature of the tert-butyl reaction is 130 to 220 ℃.
7. The method of synthesis of claim 1, wherein the inert gas is nitrogen; the introduction amount of the inert gas is 10 to 25NM 3 /h/m 3 And (3) reaction liquid.
8. The synthesis method according to claim 1 or 7, wherein the inert gas is introduced in two stages, the amount of the inert gas introduced in the first stage is 0 to 0.01%/min of the amount of 3,3',5,5' -tetra-tert-butyl-4,4 ' -dihydroxybiphenyl substance; the amount of the substance to be introduced in the second stage is 3,3',5,5' -tetra-tert-butyl-4,4 ' -dihydroxybiphenyl 0.5 to 2%/min.
9. The synthesis method according to claim 8, wherein the first-stage reaction pressure is 0.1 to 0.4MPaG, and the second-stage reaction pressure is 0.2 to 0.6MPaG.
10. The method of synthesis according to claim 1, wherein said recrystallization employs xylene as a solvent; the mass ratio of the xylene to 3,3',5,5' -4,4' -dihydroxybiphenyl is 1-10: 1.
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| US5097080A (en) * | 1989-12-15 | 1992-03-17 | Mitsubishi Petrochemical Co., Ltd. | Process for preparing 4,4'-dihydroxybiphenyl |
| US5324868A (en) * | 1992-05-29 | 1994-06-28 | Mitsubishi Petrochemical Company, Ltd. | Method for preparing 4,4'-biphenol |
| CN1272483A (en) * | 1999-04-26 | 2000-11-08 | 住友化学工业株式会社 | Method for producing P,P'-diphenol |
| WO2004018401A1 (en) * | 2002-08-26 | 2004-03-04 | Wiley Organics, Inc. | Preparation of biphenols by oxidative coupling of alkylphenols using a recyclable copper catalyst |
| CN112142570A (en) * | 2020-09-22 | 2020-12-29 | 威海金泓高分子有限公司 | Preparation method of p-hydroxybiphenyl diphenol |
| CN113416119A (en) * | 2021-06-23 | 2021-09-21 | 四川圣效科技股份有限公司 | Method for synthesizing 4, 4' -dihydroxybiphenyl by adopting loop reactor |
| CN114181052A (en) * | 2021-12-20 | 2022-03-15 | 宁夏清研高分子新材料有限公司 | Preparation method of high-purity 4, 4' -biphenol |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5097080A (en) * | 1989-12-15 | 1992-03-17 | Mitsubishi Petrochemical Co., Ltd. | Process for preparing 4,4'-dihydroxybiphenyl |
| US5324868A (en) * | 1992-05-29 | 1994-06-28 | Mitsubishi Petrochemical Company, Ltd. | Method for preparing 4,4'-biphenol |
| CN1272483A (en) * | 1999-04-26 | 2000-11-08 | 住友化学工业株式会社 | Method for producing P,P'-diphenol |
| WO2004018401A1 (en) * | 2002-08-26 | 2004-03-04 | Wiley Organics, Inc. | Preparation of biphenols by oxidative coupling of alkylphenols using a recyclable copper catalyst |
| CN112142570A (en) * | 2020-09-22 | 2020-12-29 | 威海金泓高分子有限公司 | Preparation method of p-hydroxybiphenyl diphenol |
| CN113416119A (en) * | 2021-06-23 | 2021-09-21 | 四川圣效科技股份有限公司 | Method for synthesizing 4, 4' -dihydroxybiphenyl by adopting loop reactor |
| CN114181052A (en) * | 2021-12-20 | 2022-03-15 | 宁夏清研高分子新材料有限公司 | Preparation method of high-purity 4, 4' -biphenol |
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