CN117700708A - Preparation method for synthesizing polycarbonate by low-temperature positive pressure - Google Patents
Preparation method for synthesizing polycarbonate by low-temperature positive pressure Download PDFInfo
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- CN117700708A CN117700708A CN202311751691.4A CN202311751691A CN117700708A CN 117700708 A CN117700708 A CN 117700708A CN 202311751691 A CN202311751691 A CN 202311751691A CN 117700708 A CN117700708 A CN 117700708A
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- 239000004417 polycarbonate Substances 0.000 title claims abstract description 113
- 229920000515 polycarbonate Polymers 0.000 title claims abstract description 113
- 238000002360 preparation method Methods 0.000 title claims abstract description 22
- 230000002194 synthesizing effect Effects 0.000 title description 5
- 238000006068 polycondensation reaction Methods 0.000 claims abstract description 150
- 239000000463 material Substances 0.000 claims abstract description 90
- 239000007788 liquid Substances 0.000 claims abstract description 59
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 56
- 238000001704 evaporation Methods 0.000 claims abstract description 50
- 230000008020 evaporation Effects 0.000 claims abstract description 50
- 238000000926 separation method Methods 0.000 claims abstract description 38
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N Phenol Chemical compound OC1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 claims abstract description 33
- 239000005416 organic matter Substances 0.000 claims abstract description 33
- ROORDVPLFPIABK-UHFFFAOYSA-N diphenyl carbonate Chemical compound C=1C=CC=CC=1OC(=O)OC1=CC=CC=C1 ROORDVPLFPIABK-UHFFFAOYSA-N 0.000 claims abstract description 26
- 239000000126 substance Substances 0.000 claims abstract description 24
- 150000001875 compounds Chemical class 0.000 claims abstract description 19
- 238000006243 chemical reaction Methods 0.000 claims abstract description 16
- 150000002148 esters Chemical group 0.000 claims abstract description 13
- 238000001125 extrusion Methods 0.000 claims abstract description 10
- 238000002156 mixing Methods 0.000 claims abstract description 10
- 238000000034 method Methods 0.000 claims description 31
- 239000002202 Polyethylene glycol Substances 0.000 claims description 21
- 229920001223 polyethylene glycol Polymers 0.000 claims description 21
- 238000004519 manufacturing process Methods 0.000 claims description 13
- OAYXUHPQHDHDDZ-UHFFFAOYSA-N 2-(2-butoxyethoxy)ethanol Chemical compound CCCCOCCOCCO OAYXUHPQHDHDDZ-UHFFFAOYSA-N 0.000 claims description 10
- NIHNNTQXNPWCJQ-UHFFFAOYSA-N fluorene Chemical compound C1=CC=C2CC3=CC=CC=C3C2=C1 NIHNNTQXNPWCJQ-UHFFFAOYSA-N 0.000 claims description 10
- 229960002479 isosorbide Drugs 0.000 claims description 9
- 230000001476 alcoholic effect Effects 0.000 claims description 8
- KLDXJTOLSGUMSJ-JGWLITMVSA-N Isosorbide Chemical compound O[C@@H]1CO[C@@H]2[C@@H](O)CO[C@@H]21 KLDXJTOLSGUMSJ-JGWLITMVSA-N 0.000 claims description 7
- 230000015572 biosynthetic process Effects 0.000 claims description 7
- 238000003786 synthesis reaction Methods 0.000 claims description 7
- 238000010438 heat treatment Methods 0.000 claims description 6
- 229920006395 saturated elastomer Polymers 0.000 claims description 6
- KRIOVPPHQSLHCZ-UHFFFAOYSA-N propiophenone Chemical compound CCC(=O)C1=CC=CC=C1 KRIOVPPHQSLHCZ-UHFFFAOYSA-N 0.000 claims description 5
- KLDXJTOLSGUMSJ-UNTFVMJOSA-N (3s,3ar,6s,6ar)-2,3,3a,5,6,6a-hexahydrofuro[3,2-b]furan-3,6-diol Chemical compound O[C@H]1CO[C@@H]2[C@@H](O)CO[C@@H]21 KLDXJTOLSGUMSJ-UNTFVMJOSA-N 0.000 claims description 4
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 claims description 4
- POAOYUHQDCAZBD-UHFFFAOYSA-N 2-butoxyethanol Chemical compound CCCCOCCO POAOYUHQDCAZBD-UHFFFAOYSA-N 0.000 claims description 2
- SXRSQZLOMIGNAQ-UHFFFAOYSA-N Glutaraldehyde Chemical compound O=CCCCC=O SXRSQZLOMIGNAQ-UHFFFAOYSA-N 0.000 claims description 2
- YIMQCDZDWXUDCA-UHFFFAOYSA-N [4-(hydroxymethyl)cyclohexyl]methanol Chemical compound OCC1CCC(CO)CC1 YIMQCDZDWXUDCA-UHFFFAOYSA-N 0.000 claims description 2
- 238000000605 extraction Methods 0.000 abstract description 4
- 238000005809 transesterification reaction Methods 0.000 description 35
- IISBACLAFKSPIT-UHFFFAOYSA-N bisphenol A Chemical compound C=1C=C(O)C=CC=1C(C)(C)C1=CC=C(O)C=C1 IISBACLAFKSPIT-UHFFFAOYSA-N 0.000 description 32
- 239000012071 phase Substances 0.000 description 25
- 238000011084 recovery Methods 0.000 description 17
- 239000003054 catalyst Substances 0.000 description 15
- 238000005886 esterification reaction Methods 0.000 description 15
- 230000032050 esterification Effects 0.000 description 14
- 239000000047 product Substances 0.000 description 8
- 239000000203 mixture Substances 0.000 description 7
- YGYAWVDWMABLBF-UHFFFAOYSA-N Phosgene Chemical compound ClC(Cl)=O YGYAWVDWMABLBF-UHFFFAOYSA-N 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- 239000002994 raw material Substances 0.000 description 5
- 238000012360 testing method Methods 0.000 description 5
- 238000012546 transfer Methods 0.000 description 5
- PYPNFSVOZBISQN-LNTINUHCSA-K cerium acetylacetonate Chemical compound [Ce+3].C\C([O-])=C\C(C)=O.C\C([O-])=C\C(C)=O.C\C([O-])=C\C(C)=O PYPNFSVOZBISQN-LNTINUHCSA-K 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
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- 238000002844 melting Methods 0.000 description 4
- 230000008018 melting Effects 0.000 description 4
- 229920000642 polymer Polymers 0.000 description 4
- WGTYBPLFGIVFAS-UHFFFAOYSA-M tetramethylammonium hydroxide Chemical compound [OH-].C[N+](C)(C)C WGTYBPLFGIVFAS-UHFFFAOYSA-M 0.000 description 4
- 230000009286 beneficial effect Effects 0.000 description 3
- 239000007791 liquid phase Substances 0.000 description 3
- 230000014759 maintenance of location Effects 0.000 description 3
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 description 2
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 2
- 239000002585 base Substances 0.000 description 2
- 150000007514 bases Chemical class 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 239000000155 melt Substances 0.000 description 2
- 150000002989 phenols Chemical class 0.000 description 2
- -1 phosphorus compound Chemical class 0.000 description 2
- 238000006116 polymerization reaction Methods 0.000 description 2
- 239000000376 reactant Substances 0.000 description 2
- 150000003384 small molecules Chemical class 0.000 description 2
- 229930185605 Bisphenol Natural products 0.000 description 1
- CNIMWLDXHGOJAH-UHFFFAOYSA-N C1(=CC=CC=C1)O.C1(=CC=CC=C1)O.C(OC1=CC=CC=C1)(OC1=CC=CC=C1)=O Chemical compound C1(=CC=CC=C1)O.C1(=CC=CC=C1)O.C(OC1=CC=CC=C1)(OC1=CC=CC=C1)=O CNIMWLDXHGOJAH-UHFFFAOYSA-N 0.000 description 1
- LOMVENUNSWAXEN-UHFFFAOYSA-N Methyl oxalate Chemical compound COC(=O)C(=O)OC LOMVENUNSWAXEN-UHFFFAOYSA-N 0.000 description 1
- 150000001339 alkali metal compounds Chemical class 0.000 description 1
- 150000001341 alkaline earth metal compounds Chemical class 0.000 description 1
- 150000003868 ammonium compounds Chemical class 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 150000001639 boron compounds Chemical class 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- FJDQFPXHSGXQBY-UHFFFAOYSA-L caesium carbonate Chemical compound [Cs+].[Cs+].[O-]C([O-])=O FJDQFPXHSGXQBY-UHFFFAOYSA-L 0.000 description 1
- 229910000024 caesium carbonate Inorganic materials 0.000 description 1
- 150000004650 carbonic acid diesters Chemical class 0.000 description 1
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- 239000011574 phosphorus Substances 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
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- 230000002441 reversible effect Effects 0.000 description 1
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- 229910000030 sodium bicarbonate Inorganic materials 0.000 description 1
- 235000017557 sodium bicarbonate Nutrition 0.000 description 1
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- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 1
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- 230000002588 toxic effect Effects 0.000 description 1
- 239000003643 water by type Substances 0.000 description 1
- 238000004383 yellowing Methods 0.000 description 1
Landscapes
- Polyesters Or Polycarbonates (AREA)
Abstract
The invention provides a preparation method of polycarbonate synthesized by low-temperature positive pressure, which comprises the following steps: (1) Mixing an ester exchange material obtained by ester exchange reaction of diphenyl carbonate and a dihydroxyl compound with a non-alcohol polar organic matter, performing polycondensation reaction, and performing a liquid-liquid separation process to obtain a light phase substance and a heavy phase substance; (2) And (3) carrying out flash evaporation and extrusion on the heavy phase material in the step (1) to obtain the polycarbonate. According to the invention, the phenol generated by the extraction polycondensation reaction of the non-alcohol polar organic matters is added in the polycondensation reaction for preparing the polycarbonate, so that the polycondensation reaction is carried out under the conditions of low temperature and positive pressure, and the prepared polycarbonate has the characteristics of high number average molecular weight, low yellowness index and high quality.
Description
Technical Field
The invention belongs to the technical field of polycarbonate, and particularly relates to a preparation method for synthesizing polycarbonate by low-temperature positive pressure.
Background
Polycarbonate (PC) is a transparent resin having high strength, high toughness, high heat resistance, high shock resistance, and good processability. Currently, there are two main methods for the production of polycarbonates: firstly, a phosgene method; and secondly, a melting method. Most of the early manufacturers adopt the phosgene method, however, because phosgene is extremely toxic and the public pay more attention to environmental protection, newly-built PC production bases basically adopt a melting method which is more environment-friendly, but the polycarbonate produced by the melting method is poorer than the phosgene method in certain performances, mainly because the operation temperature of the phosgene method is much lower than that of the melting method. Studies have shown that the higher the temperature, the greater the impact on the polycarbonate, with increased branching and crosslinking products and increased degradation as the reaction temperature increases (Deng Cheng. Melt transesterification process for the synthesis of polycarbonates and process exploration, university of Qingdao technology, 2017.).
For the melt process for preparing PC, the polycondensation reaction is a reversible reaction, and only the small molecules are continuously removed, so that the reaction degree of polycarbonate (increase in molecular weight) can be increased, but since the viscosity of the system increases sharply with the decrease of the system reactants and the increase of the molecular weight of polycarbonate, the viscosity of the last polycondensation reaction vessel can usually reach about 300 to 1000pa·s at the operating temperature of the polycondensation reaction vessel, and in this case, only the temperature and the vacuum degree are increased in order to increase the molecular weight of the polymer (increase in positive reaction rate).
CN113801313a discloses a preparation method of high molecular weight polycarbonate and polycarbonate, the preparation method uses carbonic diester and dihydroxyl compound as raw materials, and the raw materials are mixed and preheated after adding catalyst, and then transesterification, pre-polycondensation and final polycondensation are sequentially carried out under the conditions that the temperature is 210-320 ℃ and the absolute pressure is 0.01-30 kPa; the polycarbonate prepared by the preparation method provided by the technical scheme has narrower molecular weight distribution, the average molecular weight can reach 4w, but the temperature of the last kettle can reach 320 ℃.
CN105315445a discloses a process for synthesizing polycarbonate, which comprises that bisphenol a and isosorbide are respectively and uniformly mixed with dimethyl oxalate in a molten state to carry out esterification reaction, and the reaction products after esterification of the bisphenol a and the isosorbide are polymerized to obtain bisphenol a-isosorbide type copolymer polycarbonate. The temperature of the polycondensation reaction in the polycarbonate synthesis process provided by the technical scheme is 250-310 ℃.
CN101896535a discloses a process for producing a polycarbonate which comprises using at least two reactors in series to contain a polymer having at least one linking group-CH in the molecule 2 Dihydroxyl of dihydroxyl compound of-O-In the melt polycondensation of a base compound and a carbonic acid diester to produce a polycarbonate, the temperature difference between the polymer temperature and the heating medium in the reactor is set to 80 ℃ or lower when the reduced viscosity of the produced polycarbonate is 0.10dl/g or lower, 60 ℃ or lower when the reduced viscosity exceeds 0.10dl/g or lower and 0.40dl/g or lower, and 40 ℃ or lower when the reduced viscosity exceeds 0.40 dl/g. The reaction temperature of the last kettle of the polycondensation process in the production of the polycarbonate is 210-270 ℃.
In the prior art, a polycarbonate product with a certain polymerization degree is prepared by increasing the temperature, however, side effects are also brought about by high temperature, and as a certain residence time is needed for reactants in a polycondensation reactor and a high temperature environment is added, substances are decomposed, impurities are generated, so that the polycarbonate is yellowing, and the quality of the polycarbonate is reduced.
Therefore, there is a need to develop a method for producing a polycarbonate which is environmentally friendly and has high quality of the product polycarbonate.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide a preparation method for synthesizing polycarbonate by low-temperature positive pressure, and the polycarbonate prepared by the preparation method has the characteristics of high number average molecular weight, low yellowness index and high quality.
In order to achieve the aim of the invention, the invention adopts the following technical scheme:
the invention provides a preparation method of polycarbonate synthesized by low-temperature positive pressure, which comprises the following steps:
(1) Mixing an ester exchange material obtained by ester exchange reaction of diphenyl carbonate and a dihydroxyl compound with a non-alcohol polar organic matter, performing polycondensation reaction, and performing a liquid-liquid separation process to obtain a light phase substance and a heavy phase substance;
(2) And (3) carrying out flash evaporation and extrusion on the heavy phase material in the step (1) to obtain the polycarbonate.
In the present invention, the low Wen Yizhi temperature is 220 ℃ or less, for example 180 ℃, 182 ℃, 184 ℃, 186 ℃, 190 ℃, 195 ℃, 200 ℃, 205 ℃, 210 ℃ or 215 ℃, etc., and the positive pressure is 0MPaG or more, for example 0.1MPaG, 0.5MPaG, 1MPaG, 3MPaG or 5MPaG, etc.
In the present invention, the light phase material means that the density is not more than 1200kg/m 3 For example 700kg/m 3 、750kg/m 3 、800kg/m 3 、850kg/m 3 、900kg/m 3 、950kg/m 3 、1000kg/m 3 、1050kg/m 3 、1100kg/m 3 Or 1150kg/m 3 And the like, more preferably not more than 1100kg/m 3 Even more preferably not more than 900kg/m 3 The method comprises the steps of carrying out a first treatment on the surface of the The heavy phase material means a density > 1200kg/m 3 For example 1250kg/m 3 、1300kg/m 3 、1350kg/m 3 、1400kg/m 3 、1450kg/m 3 、1500kg/m 3 、1550kg/m 3 Or 1600kg/m 3 Etc.
According to the invention, the ester exchange material obtained by the ester exchange reaction of diphenyl carbonate and dihydroxyl compound is mixed with the non-alcohol polar organic matter to carry out the polycondensation reaction, phenol which is a byproduct of the polycondensation reaction exists in a liquid form in a reaction material of the polycondensation reaction, polycarbonate in the reaction material of the polycondensation reaction is in a molten state, and the non-alcohol polar organic matter is in a liquid state, so that the polycarbonate melt and the non-alcohol polar organic matter are basically in a liquid-liquid two-phase state in the polycondensation reaction, the non-alcohol polar organic matter and the phenol are miscible, the non-alcohol polar organic matter can dissolve the phenol, the polycarbonate is basically insoluble or slightly soluble, the phenol is extracted into the liquid phase of the non-alcohol polar organic matter, so that phenol on the surface of the polycarbonate melt is continuously extracted and dissolved, the phenol generated by the polycondensation reaction is continuously diffused out, the phenol generated by the polycondensation reaction can be fully extracted in a positive direction, the polycondensation reaction is carried out in the positive direction without increasing the temperature and the vacuum degree, and the polycondensation reaction is carried out at low temperature, so that the polycarbonate in the polycondensation reaction can not stay for a long time in the polycondensation reaction, other side reactions can be caused, the polycarbonate can be produced, the polycarbonate with high molecular weight can be produced, and the quality is high, and the quality of the polycarbonate is low.
Preferably, the dihydroxy compound comprises any one or a combination of at least two of bisphenol a, isomannide, isoidide, isosorbide, 1, 4-cyclohexanedimethanol, or fluorene-containing dihydroxy compounds.
Preferably, the molar ratio of diphenyl carbonate to dihydroxy compound is 1:1 to 1.1, such as 1:1.01, 1:1.02, 1:1.03, 1:1.04, 1:1.05, 1:1.06, 1:1.07, 1:1.08, or 1:1.09, etc.
In the present invention, the catalyst for the transesterification reaction and the catalyst for the polycondensation reaction are not particularly limited, and those skilled in the art can select the catalyst according to the specific raw materials of the diphenyl carbonate and the dihydroxy compound.
Preferably, the catalyst of the transesterification reaction comprises a basic compound.
Preferably, the basic compound comprises any one or a combination of at least two of an alkali metal compound, an alkaline earth metal compound, a basic boron compound, a basic phosphorus compound, or a basic ammonium compound.
Preferably, the catalyst for polycondensation reaction comprises an acetylacetonate metal complex, and the catalyst for polycondensation reaction can be selectively added for different polycondensation reaction raw materials.
It should be noted that, in the present invention, the number, temperature, pressure and time of the esterification reactors for transesterification of diphenyl carbonate and dihydroxy compounds are not particularly limited, and those skilled in the art may select materials for specific diphenyl carbonate and dihydroxy compounds, for example, diphenyl carbonate and bisphenol a transesterification include transesterification in sequence through 3 esterification reactors, and the temperatures of the 3 esterification reactors in sequence are 190 ℃, 200 ℃ and 220 ℃ and the pressures are 40kpa, 10kpa and 3kpa, respectively, and the residence times are 90min, 70min and 80min, respectively; the diphenyl carbonate, bisphenol A and isosorbide ester exchange reaction comprises the steps of sequentially carrying out ester exchange reaction through 3 esterification reactors, wherein the temperatures of the sequentially passing 3 esterification reactors are 180 ℃, 185 ℃ and 190 ℃, the pressures are 35KPaA, 10KPaA and 3KPaA, and the residence times are 70min, 70min and 80min respectively.
Preferably, the non-alcoholic polar organic matter comprises any one or a combination of at least two of formyldimethylamine, diethylene glycol butyl ether, ethylene glycol butyl ether, propiophenone or glutaraldehyde.
Preferably, the mixing of step (1) further comprises polyethylene glycol mixing.
In the invention, the polyethylene glycol has extremely strong dissolving capacity on phenolic compounds, and the addition of the polyethylene glycol can improve the extraction effect of phenol and promote the forward reaction.
Preferably, the polyethylene glycol has a number average molecular weight of 400 or less, such as 200, 220, 240, 260, 280, 300, 320, 340, 360, 380, or the like.
Preferably, the polyethylene glycol is 0-10% by mass, e.g., 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8% or 9% by mass, based on 100% by mass of the total of the non-alcoholic polar organic substance and the polyethylene glycol.
In the invention, the total mass of the non-alcohol polar organic matters and the polyethylene glycol is calculated as 100%, the mass percentage of the polyethylene glycol is 0-10%, and if the mass percentage of the polyethylene glycol is too large, the subsequent separation of the polyethylene glycol and the polycarbonate is difficult, and the energy consumption is rapidly increased. In addition, polyethylene glycol can also dissolve small amounts of polycarbonate, allowing excess polycarbonate to enter the light phase material, causing losses.
Preferably, the apparatus for polycondensation reaction in step (1) comprises at least one polycondensation reactor, wherein a reactor discharge pump is connected to the polycondensation reactor.
Preferably, the equipment of the liquid-liquid separation process comprises at least one liquid-liquid cyclone, and the liquid-liquid cyclone is connected with a reactor discharge pump.
Preferably, the light phase substance flowing out of the liquid-liquid cyclone and the gas component obtained by flash evaporation are subjected to rectification separation to obtain phenol and non-alcohol polar organic matters.
According to the invention, the non-alcohol polar organic matters obtained by rectification separation can be circularly added into the polycondensation reactor again, and when the selected non-alcohol polar organic matters slightly dissolve the polycarbonate, the dissolved polycarbonate can be returned to the polycondensation reactor together with the circularly added non-alcohol polar organic matters to continue to participate in the reaction, so that the loss of the polycarbonate is reduced.
Preferably, the apparatus for flashing comprises a first flashing conduit, a second flashing conduit and a flash devolatilization tank.
Preferably, the first flash pipeline is heated by medium-pressure steam, and the second flash pipeline is heated by heat conduction oil.
Preferably, the heating temperature of the first flash evaporation pipeline is less than or equal to the heating temperature of the second flash evaporation pipeline.
In the present invention, since the liquid phase in the material in the first flash pipeline is dominant, medium pressure steam can be used for heating, wherein the medium pressure steam means 2.5 MPaG-5 MPaG (for example, 2.8MPaG, 3MPaG, 3.5MPaG, 4MPaG, 4.5MPaG or 4.8MPaG, etc.) steam, and the reason for selecting the medium pressure steam is that: (1) medium pressure steam is easy to obtain; (2) greater steam heat transfer coefficient (compared to conduction oil); (3) The steam temperature is constant, so that the local temperature is not easy to be too high. As the liquid in the first flash tube is continuously vaporized, the gas is much when reaching the outlet, the heat transfer is deteriorated, and the heat transfer coefficient in the tube is deteriorated, so that the heat transfer can be effectively performed only by improving the heat transfer temperature difference, and the second flash tube is heated by adopting high-temperature heat conduction oil.
Preferably, the rectification separation device comprises a first rectification column and a second rectification column.
Preferably, the apparatus for rectifying separation further comprises a third rectifying column.
In the invention, if the boiling point of the non-alcohol polar organic matters is lower than that of phenol, a third rectifying tower can be added to the rectifying and separating equipment, the second rectifying tower returns the matters separated from the top of the non-alcohol polar organic matters to the polycondensation reactor, phenol is discharged from the top of the third rectifying tower, and the non-alcohol polar organic matters separated from the bottom of the third rectifying tower return to the polycondensation reactor.
Preferably, the polycondensation reactor and the first flash conduit are each independently operated at a temperature of 200 ℃ or less, such as 182 ℃, 184 ℃, 186 ℃, 188 ℃, 190 ℃, 192 ℃, 194 ℃, 196 ℃, 198 ℃, or the like.
Preferably, the pressure of the polycondensation reactor is equal to or greater than the saturated vapor pressure and normal pressure of the non-alcohol polar organic matter at the operating temperature of the polycondensation reactor.
In the invention, the pressure of the polycondensation reactor is more than or equal to the saturated vapor pressure of the non-alcohol polar organic matters and the larger value in normal pressure at the operating temperature of the polycondensation reactor is to maintain the non-alcohol polar organic matters to be in liquid state.
Preferably, the residence time of the material in the polycondensation reactor is from 1 to 3 hours, for example 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours, 1.9 hours, 2 hours, 2.4 hours, 2.6 hours or 2.8 hours, etc.
Preferably, the mass percentage of polycarbonate in the material flowing out of the outlet of the polycondensation reactor is 5-20%, for example 6%, 8%, 10%, 12%, 14%, 16% or 18% etc.
Preferably, the viscosity of the material flowing out of the outlet of the polycondensation reactor is less than or equal to 10 Pa.S at the operating temperature of the polycondensation reactor, for example 1 Pa.S, 2 Pa.S, 3 Pa.S, 4 Pa.S, 5 Pa.S, 6 Pa.S, 7 Pa.S, 8 Pa.S, 9 Pa.S, etc.
In the invention, the viscosity of the material flowing out of the discharge port of the polycondensation reactor and the mass percentage of the polycarbonate in the material flowing out of the discharge port of the polycondensation reactor can be regulated by the flow of the non-alcohol polar organic matters added into the polycondensation reactor, the viscosity of the material flowing out of the discharge port of the polycondensation reactor is less than or equal to 10 Pa.S at the operation temperature of the polycondensation reactor, and the viscosity in the polycondensation reactor is smaller (less than 10 Pa.S), thus being beneficial to the diffusion of phenol from polycarbonate melt, and the rate of extracting phenol by the non-alcohol polar organic matters is much higher than the diffusion rate of phenol, thus the viscosity of the system needs to be reduced and the internal diffusion of phenol is beneficial.
Preferably, the pressure of the feed inlet of the liquid-liquid cyclone is more than or equal to 2MpaG, such as 2.5MpaG, 3MpaG, 3.5MpaG, 4MpaG, 4.5MpaG, 5MpaG, 5.5MpaG, 6MpaG or 6.5MpaG, etc.
In the invention, the reactor discharge pump needs to have higher lift, and ensures that the pressure of the feed inlet of the liquid-liquid cyclone is more than or equal to 2MpaG, because enough lift is needed to convert the material at the discharge outlet of the polycondensation reactor into rotational flow speed for thoroughly separating the material, and the pressure of the feed inlet of the liquid-liquid cyclone is improved, so that all polycarbonate is transferred to heavy phase materials.
Preferably, the apparatus for polycondensation reaction comprises a first polycondensation reactor and a second polycondensation reactor, wherein the first polycondensation reactor is connected with a first reactor discharge pump, and the second polycondensation reactor is connected with a second reactor discharge pump.
Preferably, the equipment of the liquid-liquid separation process comprises a first liquid-liquid cyclone and a second liquid-liquid cyclone, wherein the first liquid-liquid cyclone is connected with a first reactor discharge pump, and the second liquid-liquid cyclone is connected with a second reactor discharge pump.
Preferably, the first polycondensation reactor is operated at a temperature of 160-185 ℃ (e.g., 162 ℃, 165 ℃, 170 ℃, 175 ℃, 180 ℃, or 183 ℃, etc.), and the second polycondensation reactor is operated at a temperature of 170-195 ℃ (e.g., 172 ℃, 175 ℃, 180 ℃, 185 ℃, 190 ℃, or 193 ℃, etc.).
In the present invention, the apparatus for polycondensation reaction includes a first polycondensation reaction unit and a second polycondensation reaction unit, which contributes to an increase in the number average molecular weight of the produced polycarbonate, because: the polycondensation reaction produces small molecular weight phenol, and although the invention adopts non-alcohol polar organic matter to extract phenol produced by the polycondensation reaction, the phenol can reach equilibrium in the liquid phase of the polycarbonate melt and the non-alcohol polar organic matter due to the limitation of extraction equilibrium, so that the polycondensation reaction can be further carried out by further extracting the phenol produced by the polycondensation reaction with fresh non-alcohol polar organic matter in a second scaling reactor in order to further increase the number average molecular weight of the product polycarbonate.
Preferably, the lift of the second reactor discharge pump is greater than the lift of the first reactor discharge pump.
In the invention, the lift of the second reactor discharge pump is larger than that of the first reactor discharge pump, because the second reactor discharge pump needs to introduce the heavy phase substances into the first flash pipeline by pressure, so that the pressure is reduced, and the heat is absorbed and vaporized.
Compared with the prior art, the invention has the following beneficial effects:
according to the invention, the phenol generated by the extraction polycondensation reaction of the non-alcohol polar organic matters is added in the polycondensation reaction process of preparing the polycarbonate, so that the polycondensation reaction is carried out under the conditions of low temperature and positive pressure, and the prepared polycarbonate has the characteristics of high number average molecular weight, low yellowness index and high quality. The number average molecular weight of the polycarbonate prepared by the preparation method of the low-temperature positive pressure synthetic polycarbonate is 14500-22000, and the yellowness index (YI value) is 1.2-2.5; preferably, the polycarbonate produced by the low temperature positive pressure synthetic polycarbonate production method has a number average molecular weight of 18000-22000 and a yellowness index (YI value) of 1.2-1.3.
Drawings
FIG. 1 is a schematic view of the apparatus used in the method for producing polycarbonate by low temperature positive pressure synthesis provided in example 1;
Wherein R1 is a first polycondensation reactor; r2-a first reactor discharge pump; r3-a first liquid-liquid cyclone; b1-a second polycondensation reactor; b2-a second reactor discharge pump; b3-a second liquid-liquid cyclone; b4-a first flash line; b5-a second flash conduit; b6-a flash devolatilization tank; b7-an extruder; b8-extruder vacuum pump; b9-a flash evaporation devolatilization tank vacuum pump; b10-a first rectifying tower; b11-a condenser at the top of the first rectifying tower; b12-a reboiler of the first rectifying tower; b13-a separation discharging pump; b14-a second rectifying tower; b15-a condenser at the top of the second rectifying tower; b16-a second rectifying tower reboiler; b17-a non-alcohol polar organic matter circulating pump; a1-a flash evaporation section; a2-an extrusion section; a3-a separation and recovery section;
s1 is the stream of transesterification material flowing into the first polycondensation reactor R1; s2 is a material flow flowing out from a discharge port of the first polycondensation reactor R1; s3 is a flow of material flowing into the first liquid-liquid cyclone R3; s4 is the stream of material flowing into the second polycondensation reactor B1; s5 is a material flow flowing out from a discharge port of the second polycondensation reactor B1; s6 is a flow of the material flowing into the second liquid-liquid cyclone B3; s7 is the stream of material flowing into the first flash tube B4; s8 is the stream of material flowing into extruder B7; s9 is the stream of product polycarbonate exiting extruder B7; s10, exhausting gas from a vacuum pump; s11 is the gas which flows out by flash evaporation in a flash evaporation devolatilization tank B6; s12 is a flow of light phase substances flowing out of the first liquid-liquid cyclone R3 and the second liquid-liquid cyclone B3; s13 is a stream discharged from the top of the first rectifying tower B10; s14 is the stream of phenol exiting the second rectification column B14; s15 is a stream of the non-alcohol polar organic matters flowing out of the non-alcohol polar organic matter circulating pump B17; s16 is a flow of added non-alcohol polar organic matter; s17 is a stream of non-alcoholic polar organic substance flowing into the first polycondensation reactor R1; s18 is a stream of non-alcoholic polar organic substance flowing into the second polycondensation reactor B1;
FIG. 2 is a schematic diagram of the apparatus used in the method for producing polycarbonate by low temperature positive pressure synthesis provided in example 2;
wherein, B1-polycondensation reactor; b2-a reactor discharge pump; b3-a liquid-liquid cyclone; b4-a first flash line; b5-a second flash conduit; b6-a flash devolatilization tank; b7-an extruder; b8-extruder vacuum pump; b9-a flash evaporation devolatilization tank vacuum pump; b10-a first rectifying tower; b11-a condenser at the top of the first rectifying tower; b12-a reboiler of the first rectifying tower; b13-a separation discharging pump; b14-a second rectifying tower; b15-a condenser at the top of the second rectifying tower; b16-a second rectifying tower reboiler; b17-a third rectifying tower; b18-a condenser at the top of the third rectifying tower; b19-a third rectifying tower reboiler; b20-a non-alcohol polar organic matter circulating pump; a1-a flash evaporation section; a2-an extrusion section; a3-a separation and recovery section;
s1 is the stream of transesterification material flowing into polycondensation reactor B1; s2 is a material flow flowing out from a discharge port of the polycondensation reactor B1; s3 is a flow of the material flowing into the liquid-liquid cyclone B3; s4 is the stream of material flowing into the first flash tube B4; s5 is the stream of material flowing into extruder B7; s6 is the stream of product polycarbonate exiting extruder B7; s7, exhausting gas from a vacuum pump; s8, the gas which flows out by flash evaporation in a flash evaporation devolatilization tank B6; s9 is a flow of a light-phase material flowing out of the liquid-liquid cyclone B3; s10 is a flow discharged from the top of the first rectifying tower B10; s11 is the stream of phenol exiting the third rectification column B17; s12 is a stream of the non-alcohol polar organic matters flowing out of the non-alcohol polar organic matter circulating pump B20; s13 is a flow of added non-alcohol polar organic matter; s14 is a stream of non-alcoholic polar organic matter fed into the polycondensation reactor;
FIG. 3 is a schematic view of the apparatus used in the method for producing polycarbonate by low temperature positive pressure synthesis provided in example 3;
wherein, B1-polycondensation reactor; b2-a reactor discharge pump; b3-a liquid-liquid cyclone; b4-a first flash line; b5-a second flash conduit; b6-a flash devolatilization tank; b7-an extruder; b8-extruder vacuum pump; b9-a flash evaporation devolatilization tank vacuum pump; b10-a first rectifying tower; b11-a condenser at the top of the first rectifying tower; b12-a reboiler of the first rectifying tower; b13-a separation discharging pump; b14-a second rectifying tower; b15-a condenser at the top of the second rectifying tower; b16-a second rectifying tower reboiler; b17-a non-alcohol polar organic matter circulating pump; a1-a flash evaporation section; a2-an extrusion section; a3-a separation and recovery section;
s1 is the stream of transesterification material flowing into polycondensation reactor B1; s2 is a material flow flowing out from a discharge port of the polycondensation reactor B1; s3 is a flow of the material flowing into the liquid-liquid cyclone B3; s4 is the stream of material flowing into the first flash tube B4; s5 is the stream of material flowing into extruder B7; s6 is the stream of product polycarbonate exiting extruder B7; s7, exhausting gas from a vacuum pump; s8 is a gas component which flows out by flash evaporation in a flash evaporation devolatilization tank B6; s9 is a flow of a light-phase material flowing out of the liquid-liquid cyclone B3; s10 is a flow discharged from the top of the first rectifying tower B10; s11 is the stream of phenol exiting the second rectification column B14; s12 is a stream of the non-alcohol polar organic matters flowing out of the non-alcohol polar organic matter circulating pump B17; s13 is a flow of added non-alcohol polar organic matter; s14 is a stream of non-alcoholic polar organic matter fed into the polycondensation reactor;
FIG. 4 is a schematic structural view of an apparatus used in the method for producing polycarbonate provided in comparative example 1;
wherein R1 is a first polycondensation reactor; r2-a first reactor discharge pump; b1-a second polycondensation reactor; b2-a second reactor discharge pump; b3-extruder; b4-extruder vacuum pump; b5-a first reactor primary condenser; b6-a first reactor secondary condenser; b7-a first-stage condenser of the second reactor; b8-a second reactor secondary condenser; a B9-phenol recovery pump; b10-a first polycondensation reactor vacuum pump; b11-a second polycondensation reactor vacuum pump; b12-a first rectifying tower; b13-a first rectifying tower reboiler; b14-a condenser at the top of the first rectifying tower; b15-separating and discharging pump; b16-a second rectifying tower; b17-a second rectifying tower reboiler; b18-a condenser at the top of the second rectifying tower; a1-an extrusion section; a2-a separation and recovery section;
s1 is a stream of a transesterification material obtained by transesterification reaction of diphenyl carbonate and bisphenol A flowing into a first polycondensation reactor R1; s2 is a material flow flowing out from a discharge port of the first polycondensation reactor R1; s3 is the stream of material flowing into the second polycondensation reactor B1; s4 is a material flow flowing out from a discharge port of the second polycondensation reactor B1; s5 is the stream of material flowing into extruder B3; s6 is the stream of product polycarbonate exiting extruder B3; s7, exhausting gas from a vacuum pump; s8 is gas exhausted by the first polycondensation reactor vacuum pump and the second polycondensation reactor vacuum pump; s9 is condensate of the first polycondensation reactor vacuum pump and the second polycondensation reactor vacuum pump; s10 is a flow discharged from the top of the first rectifying tower B10; s11 is the stream of phenol exiting the second rectification column B16; s12 is the stream withdrawn from the bottom of the second rectification column B16.
Detailed Description
The technical scheme of the invention is further described by the following specific embodiments. It will be apparent to those skilled in the art that the examples are merely to aid in understanding the invention and are not to be construed as a specific limitation thereof.
Example 1
The embodiment provides a preparation method of low-temperature positive pressure synthetic polycarbonate, the structure schematic diagram of the used device is shown in figure 1, the used device comprises a first polycondensation reactor R1, a first reactor discharge pump R2, a first liquid-liquid cyclone R3, a second polycondensation reactor B1, a second reactor discharge pump B2, a second liquid-liquid cyclone B3, a first flash pipeline B4, a second flash pipeline B5, a flash devolatilization tank B6, an extruder B7, an extruder vacuum pump B8, a flash devolatilization tank vacuum pump B9, a first rectification column B10, a first rectification column top condenser B11, a first rectification column reboiler B12 and a separation discharge pump B13; the device comprises a second rectifying tower B14, a second rectifying tower top condenser B15, a second rectifying tower reboiler B16 and a non-alcohol polar organic matter circulating pump B17.
The preparation method comprises the following steps:
the molar ratio is 1.06:1:2×10 -6 Mixing diphenyl carbonate, bisphenol A and a catalyst (tetramethylammonium hydroxide) for transesterification, and then sequentially carrying out transesterification in 3 esterification reactors, wherein the temperatures of the sequentially passed 3 esterification reactors are 190 ℃, 200 ℃ and 220 ℃, the pressures are 40KPaA, 10KPaA and 3KPaA, and the residence times are 90min, 70min and 80min respectively, so as to obtain the transesterification material obtained by the transesterification of the diphenyl carbonate and the bisphenol A.
Adding the above ester exchange material and non-alcohol polar organic matter (propiophenone) into a first polycondensation reactor R1, then sequentially passing through a first reactor discharge pump R2 and a first liquid-liquid cyclone R3, introducing the light phase substance produced by the first liquid-liquid cyclone R3 into a separation recovery section (A3), adding the heavy phase substance (S4) and the catalyst (cerium acetylacetonate) for polycondensation into a second polycondensation reactor B1, wherein the molar ratio of the catalyst (cerium acetylacetonate) for polycondensation to diphenyl carbonate and bisphenol A added in the above ester exchange reaction is 5×10 -6 The method comprises the steps that 1.06:1, a material (S5) flowing out of a second polycondensation reactor B1 sequentially passes through a second reactor discharge pump B2 and a second liquid cyclone B3, a light phase substance generated by the second liquid cyclone B3 enters a separation recovery device, a heavy phase substance (S7) enters a first flash pipeline B4, a second flash pipeline B5 and a flash evaporation devolatilization tank B6 to be subjected to flash evaporation, a gas component (S11) at the top of the flash evaporation devolatilization tank B6 enters a separation recovery section A3 through a flash evaporation devolatilization tank vacuum pump B9, and a material (S8) at the bottom of the flash evaporation devolatilization tank B6 enters an extruder B7 to be extruded to obtain polycarbonate.
The light phase substance (S12) flowing out of the liquid-liquid cyclone and the gas component (S11) obtained by flash evaporation are subjected to rectification separation through a separation and recovery working section A3 to obtain phenol (S14) and non-alcohol polar organic matters (S15), and the non-alcohol polar organic matters are returned to the first polycondensation reactor R1 again through a non-alcohol polar organic matter circulating pump B17.
The temperature of the transesterification material (S1) obtained by the transesterification reaction of diphenyl carbonate and bisphenol A was 220℃and the composition thereof was shown in Table 1 below.
TABLE 1
Wherein the oligomer has a number average molecular weight of 1500.
The first polycondensation reactor R1 is operated at a temperature of 180deg.C and a pressure of normal pressure (saturated vapor pressure of propiophenone at 180deg.C is-0.064 MPaG, and density is 870 kg/m) 3 ) The residence time of the materials is 1.5h, the operation temperature of the second polycondensation reactor B1 is 190 ℃, the pressure is normal pressure (the saturated vapor pressure of the propiophenone at 190 ℃ C. Is-0.05 MPaG, and the density is 860 kg/m) 3 ) The retention time of the materials is 1.5h, the first flash pipeline B4 and the second flash pipeline B5 are jacket pipes with the length of 300 meters and the inner pipe of DN40, the jacket pipe with the length of 200 meters of the first flash pipeline B4 is heated by 2.5MPaG of steam, the length of the second flash pipeline B5 is 100 meters and is heated by heat conduction oil, and the temperature of the heat conduction oil is 320 ℃.
The flow of material in the structure of the apparatus used is shown in table 2 below.
TABLE 2
In Table 2 "-" represents the result of not measuring this item.
The viscosity of the materials in the stream S2 and the stream S3 is the same as the content of polycarbonate, and the viscosity of the materials in the stream S5 and the stream S6 is the same as the content of polycarbonate.
Example 2
The embodiment provides a preparation method of polycarbonate synthesized by low-temperature positive pressure, the structure schematic diagram of the used device is shown in figure 2, the used device comprises a polycondensation reactor B1, a reactor discharge pump B2, a liquid-liquid cyclone B3, a first flash evaporation pipeline B4, a second flash evaporation pipeline B5, a flash evaporation devolatilization tank B6, an extruder B7, an extruder vacuum pump B8, a flash evaporation devolatilization tank vacuum pump B9, a first rectifying tower B10, a first rectifying tower top condenser B11, a first rectifying tower reboiler B12 and a separation discharge pump B13; the device comprises a second rectifying tower B14, a second rectifying tower top condenser B15, a second rectifying tower reboiler B16, a third rectifying tower B17, a third rectifying tower top condenser B18, a third rectifying tower reboiler B19 and a non-alcohol polar organic matter circulating pump B20.
The preparation method comprises the following steps:
the molar ratio was 1.05:0.2:0.8:1.3X10 -6 Mixing diphenyl carbonate, bisphenol A, isosorbide and a catalyst (cesium carbonate), then sequentially carrying out transesterification in 3 esterification reactors, wherein the temperatures of the sequentially passed 3 esterification reactors are 180 ℃, 185 ℃ and 190 ℃, the pressures are 35KPaA, 10KPaA and 3KPaA respectively, and the residence times are 70min, 70min and 80min respectively, so as to obtain the transesterification material obtained by the transesterification reaction of the diphenyl carbonate, the bisphenol A and the isosorbide.
Adding the ester exchange material and non-alcohol polar organic matters (formyldimethylamine) into a polycondensation reactor B1, then sequentially passing through a reactor discharge pump B2 and a liquid-liquid cyclone B3, enabling light-phase substances (S9) generated by the liquid-liquid cyclone B3 to enter a separation recovery section (A3), enabling heavy-phase substances (S4) to enter a first flash pipeline B4, a second flash pipeline B5 and a flash evaporation devolatilization tank B6, carrying out flash evaporation, enabling a gas component (S8) at the top of the flash evaporation devolatilization tank B6 to enter the separation recovery section (A3) through a flash evaporation devolatilization tank vacuum pump B9, enabling a material (S8) at the bottom of the flash evaporation devolatilization tank B9 to enter an extruder B7, and carrying out extrusion to obtain the polycarbonate.
And (3) separating the light phase substance (S9) flowing out of the liquid-liquid cyclone and the gas component (S8) obtained by flash evaporation through a separation and recovery working section (A3), rectifying and separating to obtain phenol (S11) and non-alcohol polar organic matters (S12), and returning the non-alcohol polar organic matters to the polycondensation reactor B1 again through a non-alcohol polar organic matter circulating pump B20.
The temperature of the transesterification material (S1) obtained by the transesterification reaction of diphenyl carbonate, bisphenol A and isosorbide was 200℃and the composition thereof was as shown in Table 3 below.
TABLE 3 Table 3
Wherein the polycarbonate oligomer has a number average molecular weight of 7500.
The polycondensation reactor B1 was operated at 185℃and a pressure of 0.25MPaG (saturated vapor pressure of formyldimethylamine at 185℃was 0.129MPaG, density 780 kg/m) 3 ) The retention time of the materials is 1.5h, the first flash pipeline B4 and the second flash pipeline B5 are jacket pipes with the length of 250 meters and the inner pipe of DN40, the jacket pipe with the length of 150 meters of the first flash pipeline B4 is heated by 2.5MPaG of steam, the length of the second flash pipeline B5 is 100 meters and is heated by heat conduction oil, and the temperature of the heat conduction oil is 320 ℃.
The flow of material in the structure of the apparatus used is shown in table 4 below.
TABLE 4 Table 4
In Table 4 "-" represents the result of not measuring this item.
The viscosity of the material in stream S2 and stream S3 is the same as the polycarbonate content.
Example 3
The embodiment provides a preparation method of polycarbonate synthesized by low-temperature positive pressure, the structure schematic diagram of the used device is shown in figure 3, the used device comprises a polycondensation reactor B1, a reactor discharge pump B2, a liquid-liquid cyclone B3, a first flash evaporation pipeline B4, a second flash evaporation pipeline B5, a flash evaporation devolatilization tank B6, an extruder B7, an extruder vacuum pump B8, a flash evaporation devolatilization tank vacuum pump B9, a first rectifying tower B10, a first rectifying tower top condenser B11, a first rectifying tower reboiler B12 and a separation discharge pump B13; the device comprises a second rectifying tower B14, a second rectifying tower top condenser B15, a second rectifying tower reboiler B16 and a non-alcohol polar organic matter circulating pump B17.
The preparation method comprises the following steps: the molar ratio is 1.06:0.05:0.95:5×10 -6 The diphenyl carbonate, bisphenol A, fluorene-containing dihydroxy compound shown in the formula I and catalyst (sodium bicarbonate) are mixed and sequentially pass through 3 esterification reactors to carry out transesterification, the temperatures of the sequentially passing 3 esterification reactors are respectively 180 ℃, 185 ℃ and 195 ℃, the pressures are respectively 35KPaA, 15KPaA and 5KPaA, and the residence time is respectively 60min, 70min and 90min, so that the diphenyl carbonate, bisphenol A and the transesterification material of the fluorene-containing dihydroxy compound shown in the formula I are obtained.
Adding the ester exchange material and non-alcohol polar organic matters (diethylene glycol butyl ether) into a polycondensation reactor B1, then sequentially passing through a reactor discharge pump B2 and a liquid-liquid cyclone B3, enabling light-phase matters (S9) generated by the liquid-liquid cyclone B3 to enter a separation recovery section (A3), enabling heavy-phase matters (S4) to enter a first flash pipeline B4, a second flash pipeline B5 and a flash evaporation devolatilization tank B6, carrying out flash evaporation, enabling a gas component (S8) at the top of the flash evaporation devolatilization tank B6 to enter the separation recovery section (A3) through a flash evaporation devolatilization tank vacuum pump B9, enabling a material (S8) at the bottom of the flash evaporation devolatilization tank B9 to enter an extruder B7, and carrying out extrusion to obtain the polycarbonate.
And (3) separating the light phase substance (S9) flowing out of the liquid-liquid cyclone and the gas component (S8) obtained by flash evaporation through a separation and recovery working section (A3), rectifying and separating to obtain phenol (S11) and non-alcohol polar organic matters (S12), and returning the non-alcohol polar organic matters to the polycondensation reactor B1 again through a non-alcohol polar organic matter circulating pump B17.
The temperature of the transesterification material (S1) obtained by the transesterification reaction of diphenyl carbonate, bisphenol A and the fluorene-containing dihydroxy compound shown in formula I is 205 ℃, and the composition is shown in the following Table 5.
TABLE 5
Wherein the polycarbonate oligomer has a number average molecular weight of 8600.
The polycondensation reactor B1 was operated at 190℃and at normal pressure (190℃C. With a saturation pressure of diethylene glycol butyl ether of-0.0677 MPaG and a density of 806 kg/m) 3 ) The retention time of the materials is 1.5h, the first flash pipeline B4 and the second flash pipeline B5 are jacket pipes with the length of 250 meters and the inner pipe of DN40, the jacket pipe with the length of 150 meters of the first flash pipeline B4 is heated by 2.5MPaG of steam, the length of the second flash pipeline B5 is 100 meters and is heated by heat conduction oil, and the temperature of the heat conduction oil is 320 ℃.
The flow of material in the structure of the apparatus used is shown in table 6 below.
TABLE 6
In Table 6 "-" represents the result of not measuring the item.
The viscosity of the material in stream S2 and stream S3 is the same as the polycarbonate content.
Example 4
This example provides a method for preparing a low temperature positive pressure synthetic polycarbonate which differs from example 3 only in that diethylene glycol butyl ether is replaced with diethylene glycol butyl ether and polyethylene glycol (number average molecular weight 400) in a mass ratio of 9:1; s13 is a stream of the material of the added diethylene glycol butyl ether and polyethylene glycol.
The flow of material in the structure of the apparatus used is shown in table 7 below.
TABLE 7
In Table 7 "-" represents the result of not measuring this item.
The viscosity of the material in stream S2 and stream S3 is the same as the polycarbonate content.
Otherwise, the same as in example 3 was used.
Example 5
This example provides a method for producing a polycarbonate by low temperature positive pressure synthesis, which differs from example 3 only in that the flow rate of the S14 stream is adjusted to 1000kg/h, the viscosity of the materials in the stream S2 and the stream S3 is the same as the polycarbonate content, the mass percentage of the polycarbonate in the materials (S2 and S3) flowing out from the discharge port of the polycondensation reactor is 50%, and the viscosity of the materials (S2 and S3) flowing out from the discharge port of the polycondensation reactor reaches 15.8 Pa.S at 190 ℃.
The flow of material in the structure of the apparatus used is shown in table 8 below.
TABLE 8
In Table 8 "-" represents the result of not measuring the item.
Otherwise, the same as in example 3 was used.
Comparative example 1
The structural schematic diagram of the device used in the preparation method of the polycarbonate is shown in fig. 4, and the device used comprises a first polycondensation reactor R1, a first reactor discharge pump R2, a second polycondensation reactor B1, a second reactor discharge pump B2, an extruder B3, an extruder vacuum pump B4, a first reactor primary condenser B5, a first reactor secondary condenser B6, a second reactor primary condenser B7, a second reactor secondary condenser B8, a phenol recovery pump B9, a first polycondensation reactor vacuum pump B10, a second polycondensation reactor vacuum pump B11, a first rectification column B12, a first rectification column reboiler B13, a first rectification column top condenser B14, a separation discharge pump B15, a second rectification column B16, a second rectification column reboiler B17 and a second rectification column top condenser B18.
The preparation method comprises the following steps:
the molar ratio is 1.06:1:2×10 -6 Mixing diphenyl carbonate, bisphenol A and a catalyst (tetramethylammonium hydroxide) for transesterification, and then sequentially carrying out transesterification in 3 esterification reactors, wherein the temperatures of the sequentially passed 3 esterification reactors are 190 ℃, 200 ℃ and 220 ℃, the pressures are 40KPaA, 10KPaA and 3KPaA, and the residence times are 90min, 70min and 80min respectively, so as to obtain the transesterification material obtained by the transesterification of the diphenyl carbonate and the bisphenol A.
The transesterification material is added into a first polycondensation reactor R1, then the mixture passes through a discharge pump R2 of the first reactor and is added into a second polycondensation reactor B1 together with a catalyst (cerium acetylacetonate) for polycondensation, wherein the molar ratio of the catalyst (cerium acetylacetonate) for polycondensation to the diphenyl carbonate and bisphenol A added in the transesterification is 5 multiplied by 10 -6 The material (S4) flowing out of the second polycondensation reactor B1 enters an extruder B3 through a second reactor discharge pump B2 to be extruded to obtain the polycarbonate, and a first polycondensation reactor vacuum pump B10 and a second polycondensation reactor vacuum pump B11 keep a vacuum environment for the first polycondensation reactor R1 and the second polycondensation reactor B1.
The temperature of the transesterification material (S1) obtained by the transesterification reaction of diphenyl carbonate and bisphenol A was 220℃and the composition thereof was as shown in Table 9 below.
TABLE 9
| Composition of the composition | Oligomer | Diphenyl carbonate | Bisphenol A | Phenol (P) | Impurity(s) |
| Content (wt%) | 93.3 | 3.5 | 2.8 | 0.23 | 0.17 |
Wherein the oligomer has a number average molecular weight of 1500.
The operation temperature of the first polycondensation reactor R1 is 260 ℃, the pressure is 0.6KPaA, the material residence time is 60min, the operation temperature of the second polycondensation reactor B1 is 290 ℃, the pressure is 0.05KPaA, and the material residence time is 60min.
The flow of material in the structure of the apparatus used is shown in table 10 below.
Table 10
Performance testing
The polycarbonates produced by the methods for producing polycarbonates provided in examples and comparative examples were subjected to the following performance tests.
(1) Number average molecular weight: gel permeation chromatography was used, type 150C from Waters company. The polycarbonate sample was dried in vacuo and then prepared into a 0.3wt% polycarbonate solution using tetrahydrofuran as a solvent, and the sample was filtered through a 0.5 μm filter membrane before introduction. And (3) adopting a high-efficiency PS gel chromatographic column (104-103 are connected in series in a linear way), wherein the temperature is 25 ℃, the sample injection amount is 40mL, and the average number average molecular weight is obtained after data processing after testing.
(2) Yellowness index (YI value): the method is characterized in that a CS-820N type desk-top spectrocolorimeter of Hangzhou color spectrum company is adopted, a test mode is a transmission mode, an 18mm aperture is used, an irradiation light source is a C light cold light source, an irradiation light angle is 2 degrees, a single sample is tested for 3 times and is averaged, and the thickness of a polycarbonate sheet is 1 mm.
The test results are shown in Table 11.
TABLE 11
As can be seen from the test results in Table 11, the polycarbonate obtained by the low temperature positive pressure synthetic polycarbonate preparation method provided in examples 1 to 5 has a number average molecular weight of 14500 to 22000 and a yellowness index (YI value) of 1.2 to 2.5. The polycarbonate prepared by the low temperature positive pressure synthetic polycarbonate preparation method provided in examples 1-4 has a number average molecular weight of 18000-22000 and a yellowness index (YI value) of 1.2-1.3.
In comparison with example 1, when diethylene glycol butyl ether was replaced with diethylene glycol butyl ether and polyethylene glycol (example 4) in a mass ratio of 9:1, the number average molecular weight of the polycarbonate obtained was increased because the polyethylene glycol had an extremely high dissolution ability for phenols, and the addition of polyethylene glycol gave a good effect of extracting phenol, and the number average molecular weight of the polycarbonate obtained was increased, which proved that the effect of preparing polycarbonate by adding polyethylene glycol was better.
In contrast to example 1, if the viscosity of the material flowing out of the outlet of the polycondensation reactor is too high (example 5), the number average molecular weight of the polycarbonate produced is lowered, and the yellowness index (YI value) is lowered, because the viscosity of the material at the outlet of the polycondensation reactor is too high (increased to 15.8pa·s), which is disadvantageous for the diffusion of phenol from the polymer melt, and the amount of diethylene glycol butyl ether is also small, and the ability to dissolve phenol is also relatively lowered, so that the polymerization degree of the polycarbonate produced is lowered, the number average molecular weight of the polycarbonate is only 14500, and in addition, at the liquid-liquid cyclone, since the liquid amount is small and the viscosity is large, more polycarbonate enters the separation and recovery device in the form of a light phase, and since the number average molecular weight of the polycarbonate produced is lower, a higher temperature is required for the effective removal of small molecules during the flash evaporation and extrusion, and the yellowness index (YI value) of the polycarbonate produced becomes high.
In comparison with example 1, the polycarbonate obtained by the conventional polycarbonate production method (comparative example 1) has a lower number average molecular weight and a high yellowness index (YI value).
The applicant states that the process of the invention is illustrated by the above examples, but the invention is not limited to, i.e. does not mean that the invention must be carried out in dependence on the above process steps. It should be apparent to those skilled in the art that any modification of the present invention, equivalent substitution of selected raw materials, addition of auxiliary components, selection of specific modes, etc. fall within the scope of the present invention and the scope of disclosure.
Claims (10)
1. A method for preparing polycarbonate by low-temperature positive pressure synthesis, which is characterized by comprising the following steps:
(1) Mixing an ester exchange material obtained by ester exchange reaction of diphenyl carbonate and a dihydroxyl compound with a non-alcohol polar organic matter, performing polycondensation reaction, and performing a liquid-liquid separation process to obtain a light phase substance and a heavy phase substance;
(2) And (3) carrying out flash evaporation and extrusion on the heavy phase material in the step (1) to obtain the polycarbonate.
2. The method according to claim 1, wherein the dihydroxy compound comprises any one or a combination of at least two of bisphenol a, isomannide, isoidide, isosorbide, 1, 4-cyclohexanedimethanol, or fluorene-containing dihydroxy compounds;
Preferably, the molar ratio of diphenyl carbonate to dihydroxy compound is 1:1-1.1.
3. The production method according to claim 1 or 2, wherein the non-alcoholic polar organic substance comprises any one or a combination of at least two of formyldimethylamine, diethylene glycol butyl ether, ethylene glycol butyl ether, propiophenone, and glutaraldehyde;
preferably, the mixing of step (1) further comprises polyethylene glycol mixing;
preferably, the polyethylene glycol has a number average molecular weight of 400 or less;
preferably, the mass percentage of the polyethylene glycol is 0-10% based on 100% of the total mass of the non-alcohol polar organic matter and the polyethylene glycol.
4. A process according to any one of claims 1 to 3, wherein the apparatus for polycondensation in step (1) comprises at least one polycondensation reactor to which is connected a reactor discharge pump;
preferably, the equipment of the liquid-liquid separation process comprises at least one liquid-liquid cyclone, and the liquid-liquid cyclone is connected with a reactor discharge pump;
preferably, the light phase matters flowing out of the liquid-liquid cyclone and the gas components obtained by flash evaporation are subjected to rectification separation to obtain phenol and non-alcohol polar organic matters;
Preferably, the apparatus for flashing comprises a first flashing conduit, a second flashing conduit and a flash devolatilization tank;
preferably, the first flash evaporation pipeline is heated by medium-pressure steam, and the second flash evaporation pipeline is heated by heat conduction oil;
preferably, the heating temperature of the first flash evaporation pipeline is less than or equal to the heating temperature of the second flash evaporation pipeline;
preferably, the rectification separation device comprises a first rectification column and a second rectification column;
preferably, the apparatus for rectifying separation further comprises a third rectifying column.
5. The process of claim 4, wherein the polycondensation reactor and the first flash line are each independently operated at a temperature of 200 ℃.
6. The process according to claim 4 or 5, wherein the pressure of the polycondensation reactor is not less than the larger value of the saturated vapor pressure and the normal pressure of the non-alcoholic polar organic substance at the operating temperature of the polycondensation reactor.
7. The process according to any one of claims 4 to 6, wherein the mass percentage of polycarbonate in the material flowing out of the outlet of the polycondensation reactor is 5 to 20%.
8. The process according to any one of claims 4 to 7, wherein the material flowing out of the outlet of the polycondensation reactor has a viscosity of 10 pa.s or less at the operating temperature of the polycondensation reactor;
Preferably, the pressure of a feed inlet of the liquid-liquid cyclone is more than or equal to 2MpaG.
9. The preparation method according to any one of claims 4 to 8, wherein the equipment for polycondensation reaction comprises a first polycondensation reactor and a second polycondensation reactor, the first polycondensation reactor is connected with a first reactor discharge pump, and the second polycondensation reactor is connected with a second reactor discharge pump;
preferably, the equipment of the liquid-liquid separation process comprises a first liquid-liquid cyclone and a second liquid-liquid cyclone, wherein the first liquid-liquid cyclone is connected with a first reactor discharge pump, and the second liquid-liquid cyclone is connected with a second reactor discharge pump;
preferably, the first polycondensation reactor is operated at a temperature of 160 to 185℃and the second polycondensation reactor is operated at a temperature of 170 to 195 ℃.
10. The method of claim 9, wherein the second reactor discharge pump has a lift greater than the lift of the first reactor discharge pump.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005146047A (en) * | 2003-11-12 | 2005-06-09 | Mitsubishi Chemicals Corp | Method for producing aromatic polycarbonate |
| JP2009144015A (en) * | 2007-12-12 | 2009-07-02 | Mitsubishi Chemicals Corp | Resin composition |
| JP2009144013A (en) * | 2007-12-12 | 2009-07-02 | Mitsubishi Chemicals Corp | Civil engineering and construction material component comprising polycarbonate |
| CN109880074A (en) * | 2019-02-25 | 2019-06-14 | 台州市欧威家具有限公司 | The preparation method of polycarbonate |
| WO2021200952A1 (en) * | 2020-03-31 | 2021-10-07 | 三菱ケミカル株式会社 | Thermoplastic resin having carbonate bond |
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- 2023-12-19 CN CN202311751691.4A patent/CN117700708A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005146047A (en) * | 2003-11-12 | 2005-06-09 | Mitsubishi Chemicals Corp | Method for producing aromatic polycarbonate |
| JP2009144015A (en) * | 2007-12-12 | 2009-07-02 | Mitsubishi Chemicals Corp | Resin composition |
| JP2009144013A (en) * | 2007-12-12 | 2009-07-02 | Mitsubishi Chemicals Corp | Civil engineering and construction material component comprising polycarbonate |
| CN109880074A (en) * | 2019-02-25 | 2019-06-14 | 台州市欧威家具有限公司 | The preparation method of polycarbonate |
| WO2021200952A1 (en) * | 2020-03-31 | 2021-10-07 | 三菱ケミカル株式会社 | Thermoplastic resin having carbonate bond |
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