CN117843471A - Method for purifying 2, 6-naphthalene dicarboxylic acid - Google Patents
Method for purifying 2, 6-naphthalene dicarboxylic acid Download PDFInfo
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- RXOHFPCZGPKIRD-UHFFFAOYSA-N naphthalene-2,6-dicarboxylic acid Chemical compound C1=C(C(O)=O)C=CC2=CC(C(=O)O)=CC=C21 RXOHFPCZGPKIRD-UHFFFAOYSA-N 0.000 title claims abstract description 104
- 238000000034 method Methods 0.000 title claims abstract description 22
- WPYMKLBDIGXBTP-UHFFFAOYSA-N benzoic acid Chemical compound OC(=O)C1=CC=CC=C1 WPYMKLBDIGXBTP-UHFFFAOYSA-N 0.000 claims abstract description 49
- 238000005984 hydrogenation reaction Methods 0.000 claims abstract description 40
- KKEYFWRCBNTPAC-UHFFFAOYSA-N Terephthalic acid Chemical compound OC(=O)C1=CC=C(C(O)=O)C=C1 KKEYFWRCBNTPAC-UHFFFAOYSA-N 0.000 claims abstract description 38
- 239000003054 catalyst Substances 0.000 claims abstract description 29
- 239000012535 impurity Substances 0.000 claims abstract description 28
- 238000006243 chemical reaction Methods 0.000 claims abstract description 16
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 14
- 239000001257 hydrogen Substances 0.000 claims abstract description 14
- UKVIEHSSVKSQBA-UHFFFAOYSA-N methane;palladium Chemical compound C.[Pd] UKVIEHSSVKSQBA-UHFFFAOYSA-N 0.000 claims abstract description 14
- 238000006722 reduction reaction Methods 0.000 claims abstract description 14
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 13
- 239000002904 solvent Substances 0.000 claims abstract description 12
- 239000012752 auxiliary agent Substances 0.000 claims abstract description 7
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims description 39
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 24
- RENRXKAWNUMITR-UHFFFAOYSA-N 6-acetylnaphthalene-2-carboxylic acid Chemical compound C1=C(C(O)=O)C=CC2=CC(C(=O)C)=CC=C21 RENRXKAWNUMITR-UHFFFAOYSA-N 0.000 claims description 16
- SHFLOIUZUDNHFB-UHFFFAOYSA-N 6-formylnaphthalene-2-carboxylic acid Chemical compound C1=C(C=O)C=CC2=CC(C(=O)O)=CC=C21 SHFLOIUZUDNHFB-UHFFFAOYSA-N 0.000 claims description 14
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 claims description 14
- 235000011054 acetic acid Nutrition 0.000 claims description 13
- 239000000126 substance Substances 0.000 claims description 10
- 230000008569 process Effects 0.000 claims description 9
- XNGIFLGASWRNHJ-UHFFFAOYSA-N phthalic acid Chemical compound OC(=O)C1=CC=CC=C1C(O)=O XNGIFLGASWRNHJ-UHFFFAOYSA-N 0.000 claims description 8
- 150000001732 carboxylic acid derivatives Chemical class 0.000 claims description 7
- HHHUSZQACRFSEE-UHFFFAOYSA-N 1,2,3,4-tetrahydronaphthalene-2,6-dicarboxylic acid Chemical compound OC(=O)C1=CC=C2CC(C(=O)O)CCC2=C1 HHHUSZQACRFSEE-UHFFFAOYSA-N 0.000 claims description 6
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 claims description 6
- 239000005711 Benzoic acid Substances 0.000 claims description 6
- 235000010233 benzoic acid Nutrition 0.000 claims description 6
- XBDQKXXYIPTUBI-UHFFFAOYSA-N dimethylselenoniopropionate Natural products CCC(O)=O XBDQKXXYIPTUBI-UHFFFAOYSA-N 0.000 claims description 6
- 229910052763 palladium Inorganic materials 0.000 claims description 6
- QQVIHTHCMHWDBS-UHFFFAOYSA-N isophthalic acid Chemical compound OC(=O)C1=CC=CC(C(O)=O)=C1 QQVIHTHCMHWDBS-UHFFFAOYSA-N 0.000 claims description 5
- UJMDYLWCYJJYMO-UHFFFAOYSA-N benzenetricarboxylic Acid Natural products OC(=O)C1=CC=CC(C(O)=O)=C1C(O)=O UJMDYLWCYJJYMO-UHFFFAOYSA-N 0.000 claims description 3
- 239000000203 mixture Substances 0.000 claims description 3
- 235000019260 propionic acid Nutrition 0.000 claims description 3
- IUVKMZGDUIUOCP-BTNSXGMBSA-N quinbolone Chemical compound O([C@H]1CC[C@H]2[C@H]3[C@@H]([C@]4(C=CC(=O)C=C4CC3)C)CC[C@@]21C)C1=CCCC1 IUVKMZGDUIUOCP-BTNSXGMBSA-N 0.000 claims description 3
- 238000000746 purification Methods 0.000 abstract description 10
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- 239000012065 filter cake Substances 0.000 description 14
- 238000012360 testing method Methods 0.000 description 13
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 12
- GOUHYARYYWKXHS-UHFFFAOYSA-N 4-formylbenzoic acid Chemical compound OC(=O)C1=CC=C(C=O)C=C1 GOUHYARYYWKXHS-UHFFFAOYSA-N 0.000 description 10
- 230000000694 effects Effects 0.000 description 8
- 238000010438 heat treatment Methods 0.000 description 8
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- 229920000642 polymer Polymers 0.000 description 7
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- 238000000926 separation method Methods 0.000 description 6
- 238000003756 stirring Methods 0.000 description 6
- 238000005406 washing Methods 0.000 description 6
- 229920003207 poly(ethylene-2,6-naphthalate) Polymers 0.000 description 5
- 229920000139 polyethylene terephthalate Polymers 0.000 description 5
- 239000005020 polyethylene terephthalate Substances 0.000 description 5
- 238000006116 polymerization reaction Methods 0.000 description 5
- YGYNBBAUIYTWBF-UHFFFAOYSA-N 2,6-dimethylnaphthalene Chemical compound C1=C(C)C=CC2=CC(C)=CC=C21 YGYNBBAUIYTWBF-UHFFFAOYSA-N 0.000 description 4
- UFWIBTONFRDIAS-UHFFFAOYSA-N Naphthalene Chemical compound C1=CC=CC2=CC=CC=C21 UFWIBTONFRDIAS-UHFFFAOYSA-N 0.000 description 4
- URLKBWYHVLBVBO-UHFFFAOYSA-N Para-Xylene Chemical group CC1=CC=C(C)C=C1 URLKBWYHVLBVBO-UHFFFAOYSA-N 0.000 description 4
- 239000002253 acid Substances 0.000 description 4
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- 239000000463 material Substances 0.000 description 4
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- 238000007254 oxidation reaction Methods 0.000 description 4
- 230000001590 oxidative effect Effects 0.000 description 4
- 238000006467 substitution reaction Methods 0.000 description 4
- ARCGXLSVLAOJQL-UHFFFAOYSA-N trimellitic acid Chemical class OC(=O)C1=CC=C(C(O)=O)C(C(O)=O)=C1 ARCGXLSVLAOJQL-UHFFFAOYSA-N 0.000 description 4
- 239000013078 crystal Substances 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 238000004128 high performance liquid chromatography Methods 0.000 description 3
- 239000007791 liquid phase Substances 0.000 description 3
- 239000012071 phase Substances 0.000 description 3
- 229920000728 polyester Polymers 0.000 description 3
- CXWXQJXEFPUFDZ-UHFFFAOYSA-N tetralin Chemical compound C1=CC=C2CCCCC2=C1 CXWXQJXEFPUFDZ-UHFFFAOYSA-N 0.000 description 3
- GWLLTEXUIOFAFE-UHFFFAOYSA-N 2,6-diisopropylnaphthalene Chemical compound C1=C(C(C)C)C=CC2=CC(C(C)C)=CC=C21 GWLLTEXUIOFAFE-UHFFFAOYSA-N 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- GYUVMLBYMPKZAZ-UHFFFAOYSA-N dimethyl naphthalene-2,6-dicarboxylate Chemical compound C1=C(C(=O)OC)C=CC2=CC(C(=O)OC)=CC=C21 GYUVMLBYMPKZAZ-UHFFFAOYSA-N 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
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- 239000002994 raw material Substances 0.000 description 2
- FMOUJOOWTROKLA-UHFFFAOYSA-N 1-bromonaphthalene-2,6-dicarboxylic acid Chemical compound BrC1=C(C(O)=O)C=CC2=CC(C(=O)O)=CC=C21 FMOUJOOWTROKLA-UHFFFAOYSA-N 0.000 description 1
- UOBYKYZJUGYBDK-UHFFFAOYSA-N 2-naphthoic acid Chemical compound C1=CC=CC2=CC(C(=O)O)=CC=C21 UOBYKYZJUGYBDK-UHFFFAOYSA-N 0.000 description 1
- VOCNMTIGMYPFPY-UHFFFAOYSA-N 6-methylnaphthalene-2-carboxylic acid Chemical compound C1=C(C(O)=O)C=CC2=CC(C)=CC=C21 VOCNMTIGMYPFPY-UHFFFAOYSA-N 0.000 description 1
- KOWGUGCZPNUKEY-UHFFFAOYSA-N 7bH-naphtho[1,2-b]oxirene-1a,5-dicarboxylic acid Chemical compound C12C(C=CC3=CC(=CC=C13)C(=O)O)(C(=O)O)O2 KOWGUGCZPNUKEY-UHFFFAOYSA-N 0.000 description 1
- 230000006750 UV protection Effects 0.000 description 1
- 150000001299 aldehydes Chemical class 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 238000003965 capillary gas chromatography Methods 0.000 description 1
- 238000009903 catalytic hydrogenation reaction Methods 0.000 description 1
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- 230000007613 environmental effect Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 230000036541 health Effects 0.000 description 1
- 229910001385 heavy metal Inorganic materials 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
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- 238000004949 mass spectrometry Methods 0.000 description 1
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- 230000004048 modification Effects 0.000 description 1
- 125000001624 naphthyl group Chemical group 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 1
- -1 polyethylene terephthalate Polymers 0.000 description 1
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Abstract
The invention discloses a method for purifying 2, 6-naphthalene dicarboxylic acid, and belongs to the technical field of 2, 6-naphthalene dicarboxylic acid purification. The crude 2,6 naphthalene dicarboxylic acid product is subjected to reduction reaction with hydrogen in the presence of a hydrogenation catalyst, and carboxylbenzene is adopted as an auxiliary agent in the reaction. According to the invention, the hydrogenation reaction of the crude 2, 6-naphthalene dicarboxylic acid is promoted by adding terephthalic acid, and the crude 2, 6-naphthalene dicarboxylic acid is continuously contacted with hydrogen to carry out the hydrogenation reaction under the action of a palladium-carbon catalyst, carboxybenzene and a solvent in a hydrogenation reactor, so that the purity of the 2, 6-naphthalene dicarboxylic acid is improved, the impurity content is reduced, and the catalyst can be used in the production of the 2, 6-naphthalene dicarboxylic acid.
Description
Technical Field
The invention relates to a method for purifying 2, 6-naphthalene dicarboxylic acid, and belongs to the technical field of 2, 6-naphthalene dicarboxylic acid purification.
Background
Polyethylene naphthalate (PEN) is generally used as a high-end polyester material and is usually prepared by sequentially performing transesterification and polycondensation on polymer-grade dimethyl 2, 6-naphthalate (2, 6-NDC) and Ethylene Glycol (EG) or directly performing polycondensation on polymer-grade 2, 6-naphthalate (2, 6-NDCA) and Ethylene Glycol (EG). Polyethylene naphthalate (PEN) is a new class of polyesters that began to be commercialized in the 90 th century and, like PET, can be processed into films, fibers, hollow containers and sheets. PEN is very similar to polyethylene terephthalate (PET) in chemical structure, and the difference is that benzene rings in PET molecular chains are replaced by naphthalene rings with more powerful rigidity, so that PEN has higher gas barrier, chemical stability, physical and mechanical properties, ultraviolet resistance, radiation resistance, heat resistance and the like than PET, and the PEN attracts wide attention in the world polyester industry due to excellent comprehensive properties and potential wide markets. The key point of industrial production of PEN is the research and development of the synthesis and refining process technology of polymerization grade 2, 6-naphthalene dicarboxylic acid (or 2, 6-naphthalene dicarboxylic acid dimethyl ester) which is one of the main raw materials.
At present, the polymerization grade 2,6-NDCA is mainly prepared by sequentially carrying out liquid phase oxidation and purification procedures on raw material 2, 6-dialkylnaphthalene to respectively obtain crude 2,6-NDCA and refined 2,6-NDCA, and a plurality of impurities are inevitably contained in a crude 2,6-NDCA product, and mainly comprises the following steps: such as trimellitic acid, aldehyde derivatives (e.g. 2-formyl-6-naphthoic acid, 2-acetyl-6-naphthoic acid, etc.), bromo-2, 6-NDCA, etc., the presence of these impurities will directly and inevitably affect the subsequent polymerization reaction and ultimately the quality of PEN. For example, 2-formyl-6-naphthoic acid and 2-acetyl-6-naphthoic acid (incomplete oxide) can break the polymer chain, limit the polymerization speed and the molecular mass of the polymer, and deepen the color of the polymer to influence the appearance; whereas bromo-2, 6-naphthalene dicarboxylic acid reduces the softening point of the polymer; trimellitic acid can cause branching of the polymer, affect the linearity of the polymer, and reduce the mechanical strength of the polymer. For the above reasons, crude 2,6-NDCA must be purified to make refined 2,6-NDCA meet the quality requirements of the polymerization grade.
The hydropurification process is one of the main industrial purification processes for crude 2, 6-naphthalene dicarboxylic acid, such as U.S. Pat. No. 3, 5354898 (titled: method for purifying crude aromatic carboxylic acid) for crude 2,6-NDCA (without 2-formyl-6-naphthoic acid and 2-acetyl-6-naphthoic acid) obtained by oxidation of 2, 6-dimethylnaphthalene, using a heavy metal (e.g., os, rh, ru, pd, pt, ir) supported catalyst, at a reaction pressure of 1.46-20.5 MPa and a reaction temperature of > 315℃and using a low molecular weight carboxylic acid (e.g., benzoic acid, acetic acid, propionic acid, etc.) in solution in a weight ratio to the crude 2,6-NDCA of 3-10. By catalytic hydrogenation, the brominated-2, 6-NDCA and TMA are sequentially converted into 2,6-NDCA and terephthalic acid (m-phthalic acid), so that the purity and yield of the 2,6-NDCA are greatly improved, and the catalyst is prevented from being deactivated by complexing TMA with the catalyst, so that large-particle 2,6-NDCA crystals are obtained. Compared with crude 2, 6-naphthalene dicarboxylic acid obtained by oxidizing 2, 6-dimethylnaphthalene, the amount and content of impurities in the crude 2, 6-naphthalene dicarboxylic acid obtained by oxidizing 2, 6-diisopropylnaphthalene are greatly increased, and particularly, the presence of 2-acetyl-6-naphthalene carboxylic acid is more difficult to remove by conventional hydrogenation purification methods than 2-formyl-6-naphthalene carboxylic acid, and more severe hydrogenation conditions (such as increase of reaction temperature, hydrogen partial pressure, catalyst activity and prolonged residence time) are generally required, for example, the treatment of crude 2, 6-naphthalene dicarboxylic acid obtained by oxidizing 2, 6-diisopropylnaphthalene by the method of U.S. Pat. No. 5, 5354898, which inevitably reduces the content of crude 2, 6-naphthalene dicarboxylic acid to 2, 6-dicarboxy-1, 2, 3, 4-tetrahydronaphthalene, which does not reduce the yield of 2, 6-naphthalene dicarboxylic acid and increases the energy consumption for subsequent separation. Similar to p-carboxybenzaldehyde (4-CBA) and p-carboxybenzoic acid (PT acid) in crude terephthalic acid (crude TA) prepared by oxidizing p-xylene (PX), in the PTA industry, the 4-CBA and the PT acid are strictly limited before and after hydrogenation purification, and the content of the 4-CBA and the PT acid before hydrogenation is less than or equal to 3500ppmw and less than or equal to 1000ppmw respectively; the content of the hydrogenated and purified catalyst is less than or equal to 25ppmw and 150ppmw or the total content of 4-CBA and PT acid is less than or equal to 200ppmw respectively.
Therefore, how to make the purity of 2, 6-naphthalene dicarboxylic acid in the crude 2, 6-naphthalene dicarboxylic acid hydrogenation product higher and the content of other impurities lower, especially to inhibit the production of 2, 6-dicarboxy-1, 2, 3, 4-tetrahydronaphthalene as the over-hydrogenation impurity and to reduce the content of key impurities 2-methyl-6-naphthalene carboxylic acid and 2-acetyl-6-naphthalene carboxylic acid is a technical problem to be solved.
Disclosure of Invention
The invention provides a method for purifying crude 2, 6-naphthalene dicarboxylic acid, which mainly solves the problem of high impurity content of hydrogenation products caused by poor control of hydrogenation purification reaction in the prior art.
A method for purifying 2, 6-naphthalene dicarboxylic acid comprises the step of carrying out reduction reaction on a crude 2, 6-naphthalene dicarboxylic acid product with hydrogen in the presence of a hydrogenation catalyst, wherein an auxiliary agent is added in the reaction, and carboxylbenzene is adopted as the auxiliary agent in the reaction.
Optionally, the content of the 2, 6-naphthalene dicarboxylic acid in the crude 2, 6-naphthalene dicarboxylic acid product is 90.0 to 99.8wt%.
Optionally, the crude 2,6 naphthalene dicarboxylic acid product further comprises impurities; preferably, the impurities include 2-formyl-6-naphthoic acid and/or 2-acetyl-6-naphthoic acid; the content of the 2-formyl-6-naphthoic acid is 200 to 20000ppmw; the content of the 2-acetyl-6-naphthoic acid is 200 to 20000ppmw.
Alternatively, the hydrogenation catalyst is a palladium-carbon catalyst, preferably having a palladium content of 0.01 to 0.06wt%, preferably 0.02 to 0.05wt%, based on the catalyst.
In the invention, the carboxybenzene is fully dissolved in a reaction system, compared with 2, 6-naphthalene dicarboxylic acid, the molecular weight of the carboxybenzene is smaller, the carboxybenzene is easier to enter palladium-carbon catalyst micropores, and is easier to be absorbed/desorbed by palladium crystal grain activity on the surface of the catalyst, and under the condition that the activity of the palladium-carbon catalyst is not obviously reduced, 2, 6-naphthalene dicarboxylic acid molecules are difficult to stay on the palladium crystal grain activity surface in the micropores for a long time, so that the possibility that 2, 6-naphthalene dicarboxylic acid is subjected to hydrogenation to generate 2, 6-dicarboxy-1, 2, 3, 4-tetrahydronaphthalene is greatly reduced, and the possibility that the key impurities 2-formyl-6-naphthalene carboxylic acid and 2-acetyl-6-naphthalene carboxylic acid have no obvious change in the hydrogenation purification process, so that the possibility of byproducts is reduced, and the product purity of the 2, 6-naphthalene dicarboxylic acid is further improved.
In the invention, the hydrogenation product generated by the reaction auxiliary agent has great difference with the solubility of the 2, 6-naphthalene dicarboxylic acid, and can be easily purified by a simple separation method without affecting the product purity of the 2, 6-naphthalene dicarboxylic acid.
Optionally, the palladium-carbon catalyst is 5-8 mesh.
Optionally, the carboxybenzene is selected from at least one of monocarboxylbenzene, dicarboxybenzene, tricarboxybenzene; the monocarboxylic benzene is preferably benzoic acid; the dicarboxybenzene is at least one selected from terephthalic acid, phthalic acid and isophthalic acid.
Optionally, the weight ratio of the carboxybenzene to the crude 2,6 naphthalene dicarboxylic acid product is 0.005-0.03:1. For example, the weight ratio of carboxybenzene to crude 2,6 naphthalene dicarboxylic acid may be in the range of 0.005:1, 0.01:1, 0.015:1, 0.02:1, 0.025:1, 0.03:1, or a combination thereof. In some embodiments, the weight ratio of carboxybenzene to crude 2,6 naphthalene dicarboxylic acid is from 0.01 to 0.025:1.
Alternatively, the hydrogen partial pressure of the reduction reaction is 0.05 to 2.5MPa, preferably 0.4 to 1.6MPa, more preferably 0.60MPa.
Optionally, the solvent used in the reduction reaction is a mixture of carboxylic acid substances and water, and the carboxylic acid substances are preferably acetic acid or propionic acid; the weight ratio of carboxylic acid substance to water in the solvent is 0.001-0.08:1, preferably 0.01-0.05:1.
Alternatively, the weight ratio of the solvent to the total of crude 2,6 naphthalene dicarboxylic acid and carboxybenzene is from 11.5 to 99:1, preferably from 15.7 to 24:1.
Alternatively, the reduction reaction adopts a fixed bed reactor, and the total amount of the crude 2,6 naphthalene dicarboxylic acid, the auxiliary agent and the solvent is LHSV relative to the hourly weight space velocity of the palladium-carbon catalyst fixed bed n For 0.25 to 6 hours -1 Preferably 1 to 5 hours -1 。
Alternatively, the temperature of the reduction reaction is 260 to 320 ℃, preferably 275 to 310 ℃.
Optionally, after the reduction reaction is finished, a product is obtained, wherein the content of 2, 6-naphthalic acid in the product is 98.5-99.9 wt%, the content of impurity 2, 6-dicarboxyl-1, 2, 3, 4-tetrahydronaphthalene is 0-800 ppmw, the content of 2-formyl-6-naphthalic acid is 0-100 ppmw, and the content of 2-acetyl-6-naphthalic acid is 0-200 ppmw.
Advantageous effects
According to the invention, the hydrogenation reaction of the crude 2, 6-naphthalene dicarboxylic acid is promoted by adding terephthalic acid, and the crude 2, 6-naphthalene dicarboxylic acid is continuously contacted with hydrogen to carry out the hydrogenation reaction under the action of a palladium-carbon catalyst, carboxybenzene and a solvent in a hydrogenation reactor, so that the purity of the 2, 6-naphthalene dicarboxylic acid is improved, the impurity content is reduced, and the catalyst can be used in the production of the 2, 6-naphthalene dicarboxylic acid.
Detailed Description
The hydrogenation reactor used in the process of the present invention has a liquid phase inlet, a gas phase inlet and a reactant outlet. During the reaction, crude 2, 6-naphthalene dicarboxylic acid slurry (containing crude 2, 6-naphthalene dicarboxylic acid, carboxybenzene and solvent) and hydrogen are respectively fed into the hydrogenation reactor from a liquid phase inlet and a gas phase inlet. The crude 2, 6-naphthalene dicarboxylic acid oxidation material in the hydrogenation reactor is continuously contacted with palladium-carbon catalyst for hydrogenation reaction under the action of hydrogen, carboxybenzene and solvent, and hydrogenated 2, 6-naphthalene dicarboxylic acid slurry (containing 2, 6-naphthalene dicarboxylic acid, 2, 6-dicarboxyl-1, 2, 3, 4-tetrahydronaphthalene, 2-formyl-6-naphthoic acid and 2-acetyl-6-naphthoic acid) is output from a product outlet pipeline of the hydrogenation reactor.
In the following examples:
the purity analysis method of the 2,6-NDCA in the product comprises the following steps: quantitative determination was performed using Agilent 1260 high performance liquid chromatography. Qualitative analysis: the spectra were obtained using standard 2,6-NDCA samples tested in liquid chromatography. And under the same conditions, carrying out liquid chromatography test on the dried product to obtain a spectrogram. The retention time and peak shape were completely identical to the standard, confirming that the major product was 2,6-NDCA. Quantitative analysis (purity determination): according to the standard sample with known purity, the peak area of the 2, 6-naphthalene dicarboxylic acid is measured, the peak area of the sample 2, 6-naphthalene dicarboxylic acid is measured, and the two are compared to obtain the purity of the sample.
Analysis of impurities in the product: quantitative determination was performed using Agilent 1260 high performance liquid chromatography. According to the literature such as (Kang Yiyou et al, capillary gas chromatography of naphthalene and tetrahydronaphthalene in air space [ J ]. J.environmental and health journal [ 2015, 11:1022-1022), (Yang Zhe et al, quantum chemistry research of tetrahydronaphthalene microstructure [ J ]. Computer & applied chemistry [ 2012, 4:465-468), (Cheng Yan et al, the effect of phase behavior on naphthalene hydrogenation reaction in water to tetrahydronaphthalene [ J ]. The analytical results of the fifteenth national chemical thermodynamics and thermal analysis conference paper abstract of China society [ J ], (Wu Zhijiang et al, high performance liquid chromatography of 2, 6-naphthalene dicarboxylic acid [ J ], analytical laboratory [ 2005,24 (1): 24-26) and (Xia Qing et al, co-Mn-Br catalyzed oxidation of 2, 6-dialkylnaphthalene to 2, 6-naphthalene dicarboxylic acid [ J ]. Chemical industry & engineering 1997,11 (4): 27-33), the analysis results of mass spectrometry were determined for the perhydro-2, 6-dicarboxyl-1, 2, 3, 4-naphthalene and 4-naphthalene dicarboxylic acid and 2-acetyl-6-naphthoic acid as key impurities. And (3) determining the area of the key impurity according to the standard sample of the key impurity with known purity, determining the peak area of the key impurity of the sample, and comparing the area and the peak area to obtain the content of the impurity in the sample.
Example 1
(1) An amount of crude 2, 6-naphthalenedicarboxylic acid slurry was prepared, based on 100 parts by weight, 2 parts by weight of acetic acid, 4 parts by weight of a crude 2, 6-naphthalenedicarboxylic acid product, 0.06 parts by weight of terephthalic acid and 93.94 parts by weight of pure water. The crude 2, 6-naphthalenedicarboxylic acid product had a purity of 98.65% by weight and contained a large number of impurities, and the contents of impurities 2-formyl-6-naphthoic acid and 2-acetyl-6-naphthoic acid were 1849ppmw and 2015ppmw, respectively.
(2) The crude 2, 6-naphthalene dicarboxylic acid slurry was preheated to 280℃to bring it into solution.
(3) Adding 50.0g of pure water into a fixed bed hydrogenation reactor, adding 179.29g of CTP-IV palladium-carbon catalyst (same applies below) produced by sea division of China petrochemical catalyst Co., ltd, wherein the palladium content is 0.45wt%, heating the fixed bed hydrogenation reactor to 285 ℃, introducing hydrogen into the fixed bed hydrogenation reactor, controlling the hydrogen partial pressure to be 0.60MPa, adding the crude 2, 6-naphthalene dicarboxylic acid slurry in the solution state into the fixed bed hydrogenation reactor at a rate of 7.41g/min (the hourly weight space velocity of the crude 2, 6-naphthalene dicarboxylic acid slurry relative to the palladium-carbon catalyst fixed bed is 2.48 h) -1 ) The reaction was started by maintaining the temperature at 285 ℃. After the reaction is carried out for 3 hours, continuously discharging at the rate of 7.41g/min, and collecting and discharging after 2 hours, namely the hydrogenation purification material.
(4) 2000g of the collected hydrogenated and purified material was collected and subjected to the following separation treatment: solid-liquid separation is carried out by positive/negative pressure filtration or centrifugal equipment to obtain a filter cake A (the moisture content is about 20 percent, 80g of 2, 6-naphthalene dicarboxylic acid and impurities thereof); adding the filter cake A into a high-temperature high-pressure washing tank, adding 80g of pure water, starting stirring (200 rpm), sealing, testing pressure (testing pressure 1.2 MPa), heating to 180 ℃, and filtering to obtain a filter cake B; adding the filter cake B into a high-temperature high-pressure washing tank, adding 120g of pure water, starting stirring (200 rpm), sealing, testing pressure (testing pressure is 0.5 MPa), heating to 140 ℃, and filtering to obtain a filter cake C; adding the filter cake C into a high-temperature high-pressure washing tank, adding 160g of pure water, starting stirring (200 rpm), sealing, testing pressure (testing pressure is 0.4 MPa), heating to 120 ℃, and filtering to obtain a filter cake D; and then dried (120 ℃ C., 12 h) to obtain a sample 1, and carrying out sample feeding analysis, wherein the analysis results are shown in Table 1.
Example 2
The terephthalic acid in example 1 was replaced with: benzoic acid, the others were unchanged, and finally sample 3 was obtained, sent for analysis, and the analysis results are shown in table 1.
Example 3
An amount of crude 2, 6-naphthalenedicarboxylic acid slurry prepared in step (1) in example 1 was mixed with 2 parts by weight of acetic acid, 4 parts by weight of crude 2, 6-naphthalenedicarboxylic acid, 0.06 part by weight of terephthalic acid and 93.94 parts by weight of pure water based on 100 parts by weight of the crude 2, 6-naphthalenedicarboxylic acid. The substitution is as follows: an amount of crude 2, 6-naphthalene dicarboxylic acid slurry was prepared, based on 100 parts by weight of acetic acid, 2 parts by weight of crude 2, 6-naphthalene dicarboxylic acid oxide, 4 parts by weight of terephthalic acid, 0.02 part by weight of pure water and 93.98 parts by weight of pure water. The other parts are not changed, and finally, a sample 4 is obtained and is sent for analysis, and the analysis results are shown in table 1.
Example 4
An amount of crude 2, 6-naphthalenedicarboxylic acid slurry prepared in step (1) in example 1 was mixed with 2 parts by weight of acetic acid, 4 parts by weight of crude 2, 6-naphthalenedicarboxylic acid, 0.06 part by weight of terephthalic acid and 93.94 parts by weight of pure water based on 100 parts by weight of the crude 2, 6-naphthalenedicarboxylic acid. The substitution is as follows: an amount of crude 2, 6-naphthalene dicarboxylic acid slurry was prepared, based on 100 parts by weight, of 2 parts of acetic acid, 4 parts of crude 2, 6-naphthalene dicarboxylic acid, 0.04 parts of terephthalic acid and 93.96 parts of pure water. The other parts are not changed, and finally, a sample 5 is obtained and is sent for analysis, and the analysis results are shown in table 1.
Example 5
An amount of crude 2, 6-naphthalenedicarboxylic acid slurry prepared in step (1) in example 1 was mixed with 2 parts by weight of acetic acid, 4 parts by weight of crude 2, 6-naphthalenedicarboxylic acid, 0.06 part by weight of terephthalic acid and 93.94 parts by weight of pure water based on 100 parts by weight of the crude 2, 6-naphthalenedicarboxylic acid. The substitution is as follows: an amount of crude 2, 6-naphthalene dicarboxylic acid slurry was prepared, based on 100 parts by weight, of 2 parts of acetic acid, 4 parts of crude 2, 6-naphthalene dicarboxylic acid, 0.08 part of terephthalic acid and 93.92 parts of pure water. The other was not changed, and finally, sample 6 was obtained and analyzed, and the analysis results are shown in Table 1.
Example 6
An amount of crude 2, 6-naphthalenedicarboxylic acid slurry prepared in step (1) in example 1 was mixed with 2 parts by weight of acetic acid, 4 parts by weight of crude 2, 6-naphthalenedicarboxylic acid, 0.06 part by weight of terephthalic acid and 93.94 parts by weight of pure water based on 100 parts by weight of the crude 2, 6-naphthalenedicarboxylic acid. The substitution is as follows: an amount of crude 2, 6-naphthalenedicarboxylic acid slurry was prepared, based on 100 parts by weight, 2 parts by weight of acetic acid, 4 parts by weight of a crude 2, 6-naphthalenedicarboxylic acid product, 0.12 parts by weight of terephthalic acid and 93.88 parts by weight of pure water. The other was not changed, and finally, sample 7 was obtained and analyzed, and the analysis results are shown in Table 1.
Comparative example 1
(1) An amount of crude 2, 6-naphthalenedicarboxylic acid slurry was prepared, based on 100 parts by weight, 2 parts by weight of acetic acid, 4 parts by weight of crude 2, 6-naphthalenedicarboxylic acid, and 94 parts by weight of pure water. Wherein, the purity of the 2, 6-naphthalene dicarboxylic acid in the crude product of 2, 6-naphthalene dicarboxylic acid is 98.65wt%, and the contents of impurities 2-formyl-6-naphthalene carboxylic acid and 2-acetyl-6-naphthalene carboxylic acid are 1849ppmw and 2015ppmw, respectively.
(2) The crude 2, 6-naphthalene dicarboxylic acid slurry was preheated to 280℃to bring it into solution.
(3) Adding 50.0g of pure water into a fixed bed hydrogenation reactor, adding 179.29g of 5-8 mesh palladium-carbon catalyst with 0.45wt% of palladium content, heating the fixed bed hydrogenation reactor to 285 ℃, introducing hydrogen into the fixed bed hydrogenation reactor, controlling the hydrogen partial pressure to be 0.60MPa, adding the crude 2, 6-naphthalene dicarboxylic acid slurry in the solution state into the fixed bed hydrogenation reactor at a rate of 7.41g/min (the hourly weight space velocity of the crude 2, 6-naphthalene dicarboxylic acid slurry relative to the palladium-carbon catalyst fixed bed is 2.48 h) -1 ) The reaction was started by maintaining the temperature at 285 ℃. After the reaction is carried out for 3 hours, continuously discharging at the rate of 7.41g/min, and collecting and discharging after 2 hours, namely the hydrogenation purification material.
(4) 2000g of the collected hydrogenated and purified material was collected and subjected to the following separation treatment: solid-liquid separation is carried out by positive/negative pressure filtration or centrifugal equipment to obtain a filter cake A (the moisture content is about 20 percent, 80g of 2, 6-naphthalene dicarboxylic acid and impurities thereof); adding the filter cake A into a high-temperature high-pressure washing tank, adding 80g of pure water, starting stirring (200 rpm), sealing, testing pressure (testing pressure 1.2 MPa), heating to 180 ℃, and filtering to obtain a filter cake B; adding the filter cake B into a high-temperature high-pressure washing tank, adding 120g of pure water, starting stirring (200 rpm), sealing, testing pressure (testing pressure is 0.5 MPa), heating to 140 ℃, and filtering to obtain a filter cake C; adding the filter cake C into a high-temperature high-pressure washing tank, adding 160g of pure water, starting stirring (200 rpm), sealing, testing pressure (testing pressure is 0.4 MPa), heating to 120 ℃, and filtering to obtain a filter cake D; and then drying (120 ℃ C., 12 h) to obtain a sample 2, and carrying out sample feeding analysis, wherein the analysis results are shown in Table 1.
TABLE 1 summary of sample composition analysis results
From the results in table 1, it can be seen that the hydrogenation reaction is optimized by adding benzoic acid and terephthalic acid, and compared with the reaction effect of the comparative example without benzoic acid and terephthalic acid, the hydrogenation reaction has obvious improvement effect: the invention improves the purity of the 2, 6-naphthalene dicarboxylic acid on one hand and reduces the impurity content on the other hand.
The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, various simple combinations of the technical solutions of the invention can be made, including combinations of the technical features in any other suitable way, which simple modifications and combinations should also be regarded as disclosure of the invention, all falling within the scope of the invention.
Claims (10)
1. A process for purifying 2, 6-naphthalenedicarboxylic acid, characterized in that a crude 2, 6-naphthalenedicarboxylic acid product is subjected to a reduction reaction with hydrogen in the presence of a hydrogenation catalyst, the conditions for said reduction reaction comprising: the reaction adopts carboxybenzene as an auxiliary agent.
2. The method for purifying 2, 6-naphthalenedicarboxylic acid according to claim 1, wherein the content of 2, 6-naphthalenedicarboxylic acid in the crude 2, 6-naphthalenedicarboxylic acid is 90.0 to 99.8% by weight.
3. A process for purifying 2, 6-naphthalenedicarboxylic acid as claimed in claim 1 or 2, wherein,
the crude 2, 6-naphthalene dicarboxylic acid contains impurities; preferably, the impurities comprise 2-formyl-6-naphthoic acid and/or 2-acetyl-6-naphthoic acid; more preferably, the content of the 2-formyl-6-naphthoic acid is 200 to 20000ppmw; and/or the content of the 2-acetyl-6-naphthoic acid is 200 to 20000ppmw;
and/or the hydrogenation catalyst is a palladium-carbon catalyst, preferably the palladium content is 0.01-0.06 wt%, preferably 0.02-0.05 wt%;
preferably, the palladium on carbon catalyst is 5-8 mesh.
4. A method of purifying 2, 6-naphthalene dicarboxylic acid according to any one of claims 1 to 3, wherein the carboxybenzene is selected from at least one of mono-carboxybenzene, di-carboxybenzene, tri-carboxybenzene; the monocarboxylic benzene is preferably benzoic acid; the dicarboxybenzene is at least one selected from terephthalic acid, phthalic acid and isophthalic acid.
5. The process for purifying 2, 6-naphthalenedicarboxylic acid according to any one of claims 1 to 4, wherein the weight ratio of carboxybenzene to crude 2, 6-naphthalenedicarboxylic acid is from 0.005 to 0.03:1, preferably from 0.01 to 0.025:1.
6. The method for purifying 2, 6-naphthalenedicarboxylic acid according to any one of claims 1 to 5, wherein the hydrogen partial pressure of the reduction reaction is 0.05 to 2.5MPa, preferably 0.4 to 1.6MPa, more preferably 0.5 to 0.8MPa, still more preferably 0.60 to 0.70MPa.
7. A process for purifying 2, 6-naphthalenedicarboxylic acid as claimed in any one of claims 1 to 6,
the solvent adopted in the reduction reaction is a mixture of carboxylic acid substances and water, and the carboxylic acid substances are preferably acetic acid or propionic acid; the weight ratio of carboxylic acid substances to water in the solvent is 0.001-0.08:1, preferably 0.01-0.05:1;
the weight ratio of the solvent to the total amount of crude 2,6 naphthalene dicarboxylic acid and carboxybenzene is from 11.5 to 99:1, preferably from 15.7 to 24:1.
8. The method for purifying 2, 6-naphthalenedicarboxylic acid according to claim 7, wherein the reduction reaction is carried out using a fixed bed reactor, and the total amount of the crude 2, 6-naphthalenedicarboxylic acid, auxiliary agent and solvent is LHSV relative to the hourly weight space velocity of palladium-carbon catalyst fixed bed n For 0.25 to 6 hours -1 Preferably 1 to 5 hours -1 。
9. The process for purifying 2, 6-naphthalenedicarboxylic acid according to any one of claims 1 to 8, wherein the temperature of the reduction reaction is 260 to 320 ℃, preferably 275 to 310 ℃.
10. The process for the hydrodewaxing of crude 2, 6-naphthalenedicarboxylic acid according to any of claims 1 to 9, wherein after the reduction reaction, a product is obtained, the content of 2, 6-naphthalenedicarboxylic acid in the product being 98.5 to 99.9% by weight, the content of 2, 6-dicarboxy-1, 2, 3, 4-tetrahydronaphthalene as impurity being 0 to 800ppmw, the content of 2-formyl-6-naphthalenecarboxylic acid being 0 to 100ppmw and the content of 2-acetyl-6-naphthalenecarboxylic acid being 0 to 200ppmw.
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