CN111039777A - Refining and purifying method of dodecyl dicarboxylic acid with high yield and low cost - Google Patents
Refining and purifying method of dodecyl dicarboxylic acid with high yield and low cost Download PDFInfo
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- -1 dodecyl dicarboxylic acid Chemical compound 0.000 title claims abstract description 134
- SNRUBQQJIBEYMU-UHFFFAOYSA-N Dodecane Natural products CCCCCCCCCCCC SNRUBQQJIBEYMU-UHFFFAOYSA-N 0.000 title claims abstract description 130
- 238000000034 method Methods 0.000 title claims abstract description 99
- 238000007670 refining Methods 0.000 title claims abstract description 55
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims abstract description 267
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 171
- 238000005406 washing Methods 0.000 claims abstract description 93
- 239000012065 filter cake Substances 0.000 claims abstract description 89
- 239000002904 solvent Substances 0.000 claims abstract description 68
- 238000001914 filtration Methods 0.000 claims abstract description 63
- 239000012452 mother liquor Substances 0.000 claims abstract description 48
- 238000001035 drying Methods 0.000 claims abstract description 44
- 239000002994 raw material Substances 0.000 claims abstract description 27
- DCKVNWZUADLDEH-UHFFFAOYSA-N sec-butyl acetate Chemical compound CCC(C)OC(C)=O DCKVNWZUADLDEH-UHFFFAOYSA-N 0.000 claims abstract description 11
- 238000002425 crystallisation Methods 0.000 claims description 128
- 230000008025 crystallization Effects 0.000 claims description 128
- 238000001816 cooling Methods 0.000 claims description 95
- 238000002386 leaching Methods 0.000 claims description 70
- 239000013078 crystal Substances 0.000 claims description 58
- 239000000706 filtrate Substances 0.000 claims description 57
- 230000008569 process Effects 0.000 claims description 54
- 238000003756 stirring Methods 0.000 claims description 51
- 239000000047 product Substances 0.000 claims description 50
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 47
- 238000000926 separation method Methods 0.000 claims description 44
- 239000008367 deionised water Substances 0.000 claims description 39
- 229910021641 deionized water Inorganic materials 0.000 claims description 39
- 239000003712 decolorant Substances 0.000 claims description 36
- WMRCTEPOPAZMMN-UHFFFAOYSA-N 2-undecylpropanedioic acid Chemical compound CCCCCCCCCCCC(C(O)=O)C(O)=O WMRCTEPOPAZMMN-UHFFFAOYSA-N 0.000 claims description 32
- 239000007788 liquid Substances 0.000 claims description 31
- 239000000498 cooling water Substances 0.000 claims description 26
- 238000005185 salting out Methods 0.000 claims description 23
- 239000000463 material Substances 0.000 claims description 19
- 238000010533 azeotropic distillation Methods 0.000 claims description 18
- 239000012043 crude product Substances 0.000 claims description 17
- OFOBLEOULBTSOW-UHFFFAOYSA-N Malonic acid Chemical compound OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 claims description 16
- 238000000746 purification Methods 0.000 claims description 16
- 238000000855 fermentation Methods 0.000 claims description 15
- 230000004151 fermentation Effects 0.000 claims description 15
- 238000010438 heat treatment Methods 0.000 claims description 15
- 239000011229 interlayer Substances 0.000 claims description 14
- 238000001953 recrystallisation Methods 0.000 claims description 14
- 238000004064 recycling Methods 0.000 claims description 13
- 238000004519 manufacturing process Methods 0.000 claims description 12
- 239000002002 slurry Substances 0.000 claims description 12
- TVIDDXQYHWJXFK-UHFFFAOYSA-N dodecanedioic acid Chemical compound OC(=O)CCCCCCCCCCC(O)=O TVIDDXQYHWJXFK-UHFFFAOYSA-N 0.000 claims description 10
- 238000006243 chemical reaction Methods 0.000 claims description 9
- 239000002253 acid Substances 0.000 claims description 8
- 238000002156 mixing Methods 0.000 claims description 7
- 238000003860 storage Methods 0.000 claims description 7
- 238000004042 decolorization Methods 0.000 claims description 6
- 239000010410 layer Substances 0.000 claims description 6
- 238000011084 recovery Methods 0.000 claims description 6
- 238000004090 dissolution Methods 0.000 claims description 4
- 238000004821 distillation Methods 0.000 claims description 4
- 230000000813 microbial effect Effects 0.000 claims description 4
- 239000010413 mother solution Substances 0.000 claims description 4
- 150000001335 aliphatic alkanes Chemical class 0.000 claims description 3
- 238000010923 batch production Methods 0.000 claims description 2
- LHFQJLUDFHACLD-UHFFFAOYSA-N butan-2-yl acetate hydrate Chemical compound O.CCC(C)OC(C)=O LHFQJLUDFHACLD-UHFFFAOYSA-N 0.000 claims description 2
- 238000009833 condensation Methods 0.000 claims description 2
- 230000005494 condensation Effects 0.000 claims description 2
- 239000000284 extract Substances 0.000 claims description 2
- 239000000203 mixture Substances 0.000 claims description 2
- 239000003795 chemical substances by application Substances 0.000 abstract description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 abstract 2
- 229910052757 nitrogen Inorganic materials 0.000 abstract 1
- 239000004677 Nylon Substances 0.000 description 12
- 229920001778 nylon Polymers 0.000 description 12
- 238000001556 precipitation Methods 0.000 description 7
- 229910052799 carbon Inorganic materials 0.000 description 6
- 239000006227 byproduct Substances 0.000 description 5
- 239000012535 impurity Substances 0.000 description 4
- 238000006068 polycondensation reaction Methods 0.000 description 4
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 238000009825 accumulation Methods 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 150000004985 diamines Chemical class 0.000 description 2
- POULHZVOKOAJMA-UHFFFAOYSA-N dodecanoic acid Chemical compound CCCCCCCCCCCC(O)=O POULHZVOKOAJMA-UHFFFAOYSA-N 0.000 description 2
- 229920006351 engineering plastic Polymers 0.000 description 2
- 239000000178 monomer Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 241000222120 Candida <Saccharomycetales> Species 0.000 description 1
- 239000005639 Lauric acid Substances 0.000 description 1
- JHWNWJKBPDFINM-UHFFFAOYSA-N Laurolactam Chemical compound O=C1CCCCCCCCCCCN1 JHWNWJKBPDFINM-UHFFFAOYSA-N 0.000 description 1
- 229920000299 Nylon 12 Polymers 0.000 description 1
- 229920000572 Nylon 6/12 Polymers 0.000 description 1
- 125000002015 acyclic group Chemical group 0.000 description 1
- 125000004442 acylamino group Chemical group 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 125000003368 amide group Chemical group 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
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- 238000003912 environmental pollution Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000005461 lubrication Methods 0.000 description 1
- 229920002521 macromolecule Polymers 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 230000009456 molecular mechanism Effects 0.000 description 1
- 238000011017 operating method Methods 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 239000002304 perfume Substances 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 229920006122 polyamide resin Polymers 0.000 description 1
- 229920001707 polybutylene terephthalate Polymers 0.000 description 1
- 229920000515 polycarbonate Polymers 0.000 description 1
- 239000004417 polycarbonate Substances 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229920006324 polyoxymethylene Polymers 0.000 description 1
- 229920013636 polyphenyl ether polymer Polymers 0.000 description 1
- 230000008092 positive effect Effects 0.000 description 1
- 125000002924 primary amino group Chemical group [H]N([H])* 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000012797 qualification Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/42—Separation; Purification; Stabilisation; Use of additives
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
① the refining method of dodecyl dicarboxylic acid with high yield and low cost includes such steps as drying the raw material of dodecyl dicarboxylic acid, ② decolouring, filtering to obtain decolouring agent filter cake, washing with acetic acid, ③ recrystallizing mother liquor, water separating, crystallizing, extracting dodecyl dicarboxylic acid, recovering solvent from filtered mother liquor, ④, azeotropic rectifying, and using sec-butyl acetate as entrainer2O3Less than or equal to 1ppm, less than or equal to 15ppm of total nitrogen calculated by N element and less than or equal to 0.2 wt% of water; the refining and purifying yield of the dodecyl dicarboxylic acid is more than or equal to 96.00 percent.
Description
Technical Field
The invention is a refining and purifying method of dodecyl dicarboxylic acid with high yield and low cost. Belonging to the purification treatment of acyclic dicarboxylic acid with more than 10 carbon atoms.
Background
Dodecyl dicarboxylic Acid (Dodecanedioic Acid) is also known as lauric Acid. Is an industrial product with early development and larger yield in the dodecyl dicarboxylic acid. It is mainly used for synthesizing high molecular material, perfume, medicine, etc. Among them, the long carbon chain nylon (also called polyamide resin) engineering plastic synthesized by polycondensation reaction of polycondensation monomer and diamine is one of the most important applications.
Nylon is a kind of high molecular compound whose molecular main chain contains amide group (-NHCO-). The nylon molecular structure contains a large amount of acylamino, and the tail end of a macromolecule is amino or carboxyl, so that the nylon is a crystalline polymer which has strong polarity, can form hydrogen bonds among molecules and has certain reaction activity. Nylon is one of the five most expensive engineering plastics (nylon, polyformaldehyde, polycarbonate, polyphenyl ether and polybutylene terephthalate), the most diverse, the most widely used and the oldest qualification.
The molecular mechanism of long-chain nylon endows the long-chain nylon with good comprehensive performance, the strength is higher than that of metal, the mechanical performance, the heat resistance, the wear resistance, the chemical resistance, the flame retardance and the self-lubrication are excellent, the friction coefficient is low, the processing is easy, and the long-chain nylon can be processed into various plastic products, also can be drawn into fibers, and also can be processed into films, coatings, adhesives and the like. The method is widely applied to the fields of automobiles, electronics, electrics, machinery, communication, military, aerospace and the like.
Long carbon chain nylon synthesized by using dodecyl dicarboxylic acid as raw material and using polycondensation monomer to produce polycondensation reaction with diamine mainly includes nylon 12, nylon 612, nylon 1112 and nylon 1212, etc.,
the dodecyl dicarboxylic acid does not exist in the nature, is mainly prepared by an organic synthesis method and a biological fermentation method, and has the advantages of long process route, high cost, low yield, potential safety hazard and environmental pollution.
The biological fermentation method mainly comprises the following steps of12Normal alkane is used as raw material, and is fermented by candida to convert monoalkyl into dodecyl dicarboxylic acid, and then the dodecyl dicarboxylic acid product is obtained by crude product purification and refinement. The dodecyl dicarboxylic acid produced by the method has wide raw material source,Simple production process, low investment and low production cost. Therefore, most of the dodecyl dicarboxylic acids sold in the market at present are products produced by a biological fermentation method.
The purity and appearance of the product are seriously affected because the fermentation product contains a small amount of impurities such as mycoprotein, pigment, iron ion compounds and the like. Therefore, the refining and purifying process is a crucial link for preparing the dodecyl dicarboxylic acid by microbial fermentation.
The dodecyl dicarboxylic acid produced by the microbial fermentation method is purified and refined by recrystallization mainly by a solvent method. The solvent mainly adopts acetic acid, methanol and the like. Tests and production practices show that acetic acid is superior to other organic solvents in refining time, refining solvent consumption and purity of crystallized products.
In the prior art, a dodecyl dicarboxylic acid crude product prepared by a fermentation method is used as a raw material, acetic acid is used as a solvent, the dodecyl dicarboxylic acid product is prepared by recrystallization refining and purifying, decoloring, filtering, cooling, crystallizing, centrifugal separation, filter cake washing and drying, and after a crystallization mother liquor is subjected to solvent recovery, an obtained heavy component is repeatedly recycled and reused as a refining and purifying raw material. Or as a raw material for preparing mixed dodecyl dicarboxylic acid.
The prior art has the following defects:
1. in the prior art, a crude product with the water content of 20-25 wt% is used as a refined raw material. The drying equipment is saved, the operation steps are simplified, and the production cost is reduced. However, the water carried by the crude raw material reduces the solubility of the refined and purified dodecyl dicarboxylic acid in an acetic acid solvent, so that part of long carbon chain dicarboxylic acid crystals enter a filter cake along with activated carbon, the dicarboxylic acid loss is caused, and the refining and purifying yield of the dicarboxylic acid is reduced.
2. After the crystallization mother liquor is subjected to solvent recovery, the obtained heavy component is used as a refined purification raw material to be repeatedly recovered and reused, so that the accumulation of other mixed dibasic acid and other impurities generated in the fermentation process is caused, and the product quality of the dodecyl dicarboxylic acid is influenced.
3. And recovering the solvent from the crystallization mother liquor, and using the obtained heavy component as a raw material for preparing the mixed dodecyl dicarboxylic acid. The main product of the dodecyl dicarboxylic acid dissolved in the crystallization mother liquor is produced and sold as a long carbon chain mixed dicarboxylic acid by-product. The grade and the economic benefit of the main product of the dodecyl dicarboxylic acid contained in the product are reduced. Meanwhile, the yield of the refined dodecyl dicarboxylic acid main product is reduced.
The main component in the crystallization mother liquor is solvent acetic acid, dodecyl dicarboxylic acid which is not crystallized and still dissolved in the mother liquor, and a small amount of water and other impurities. Usually, the amount of mixed dodecanedicarboxylic acid is about 4 to 6 wt%, wherein the dodecanedicarboxylic acid accounts for about 90 to 95% of the total weight of the mixed dodecanedicarboxylic acid dissolved in the crystallization mother liquor, and the amount of mixed dodecanedicarboxylic acid by-produced in addition to the dodecanedicarboxylic acid is only about 5 to 10% of the total weight of the dodecanedicarboxylic acid dissolved in the crystallization mother liquor.
4. In the prior art, a conventional distillation method is adopted for recovering a solvent in a mother solution, the mother solution at the bottom of a distillation kettle is continuously concentrated, thickened and deteriorated along with the rise of the temperature, part of materials are carbonized, and the color is darkened. In addition to the reduction of the recovery yield of the by-products, the difficulty of the subsequent decoloring purification treatment process is increased, or even the quality of the by-products is adversely affected.
Like all chemical products, the improvement of refining and purifying yield and the reduction of production cost are the constant subjects of the refining and purifying industry of the dodecyl dicarboxylic acid. It is expected that a purification method for refining dodecanedicarboxylic acid with high yield and low cost is provided.
Disclosure of Invention
The invention aims to avoid the defects in the prior art and provides a method for refining and purifying dodecyl dicarboxylic acid, which has high product yield, lower refining cost and high purity.
The object of the invention can be achieved by the following measures:
the low-cost refining and purifying method of the dodecyl dicarboxylic acid is characterized in that a dodecyl dicarboxylic acid crude product prepared by a fermentation method is used as a raw material, acetic acid is used as a solvent, the dodecyl dicarboxylic acid product is prepared by recrystallization treatment and purification, decoloration and filtration, cooling crystallization, centrifugal separation, filter cake washing and drying processes, heavy components obtained after recrystallization of a mother liquor are subjected to solvent recovery are mixed with the dodecyl dicarboxylic acid crude product and are repeatedly recycled as a refining and purifying raw material, and the method is characterized in that:
①, the raw material dodecyl dicarboxylic acid crude product for refining and purification is directly fed into the subsequent decoloring process without drying treatment;
②, washing the decolorant filter cake obtained after decoloration and filtration with a solvent acetic acid, and combining the obtained decolorant filter cake washing liquid and the decolorant filtration filtrate to enter a subsequent cooling crystallization process so as to recover the dodecyl dicarboxylic acid carried in the decolorant activated carbon;
③, before recovering the solvent, the recrystallization mother liquor firstly elutes and crystallizes, and then extracts the dodecyl dicarboxylic acid product dissolved in the crystallization mother liquor, wherein the elutriation crystallization is to add deionized water into the crystallization mother liquor to crystallize and separate the dodecyl dicarboxylic acid product dissolved in the acetic acid solvent, then the filtration and the separation are carried out, the obtained dodecyl dicarboxylic acid crystal is combined with the crystal obtained by the first recrystallization, and the combined crystal and the crystal are subjected to the subsequent leaching and drying processes to jointly prepare the dodecyl dicarboxylic acid product;
④ recovering solvent from the filtered mother liquid after water separation and crystallization, recovering and utilizing by azeotropic distillation, the entrainer is sec-butyl acetate, separating water from acetic acid by azeotropic distillation process, the separated water is used as water for water separation and crystallization in ③, and the separated solvent acetic acid is used as solvent in the refining and purification process of dodecyl dicarboxylic acid.
The invention has the technical characteristics that ② decolorant filter cake obtained after decoloration and filtration is washed by solvent acetic acid, the obtained decolorant filter cake washing liquid and decolorant filtration filtrate are combined to enter the subsequent cooling and crystallization process, the dodecyl dicarboxylic acid carried in decolorant active carbon is successfully recovered, the invention makes technical contribution to improving the purification yield of the refined and purified dodecyl dicarboxylic acid, simultaneously, the invention solves the technical problems that in the prior art, the water carried by the crude product raw material reduces the solubility of the refined and purified dodecyl dicarboxylic acid in the acetic acid solvent, leads partial long carbon chain dicarboxylic acid raw material to enter the filter cake along with the active carbon, causes the dicarboxylic acid loss, thereby reducing the refining and purifying yield of the dodecyl dicarboxylic acid, leads the crude product of the refined and purified dodecyl dicarboxylic acid raw material to be free of drying treatment, and directly enters the subsequent decoloration process,
the invention is characterized in that ③ recrystallization mother liquor is firstly crystallized by water precipitation and then the dodecyl dicarboxylic acid product dissolved in the crystallization mother liquor is extracted again before the solvent is recovered, thereby solving the technical problem that in the prior art, the dodecyl dicarboxylic acid main product dissolved in the crystallization mother liquor is totally produced and sold as a long carbon chain mixed dicarboxylic acid byproduct.
The invention has the technical characteristics that ④ solvent in the filtered mother liquor after the elutriation and crystallization is recovered and utilized by adopting an azeotropic distillation method, an entrainer adopts sec-butyl acetate, water and acetic acid are separated by an azeotropic distillation process, the separated water is used as water for feeding of the elutriation and crystallization in the characteristic ③ and is recycled, and the separated solvent acetic acid is used as the solvent for recycling in the refining and purifying process of the dodecyl dicarboxylic acid.
The object of the invention is also achieved by the following measures:
the invention has high yieldThe low-cost refining and purifying method of dodecyl dicarboxylic acid, wherein ① item of the coarse dodecyl dicarboxylic acid product to be refined is C12The normal alkane is used as raw material, fermentation liquor prepared by microbial fermentation is filtered, decolored, acidified, crystallized and filtered to obtain filter cake crystals, the water content of the filter cake crystals is less than or equal to 20 wt%, and the filter cake crystals are directly used as refined raw materials without being dried. Is a preferable technical proposal.
The refining and purifying method of dodecyl dicarboxylic acid with high yield and low cost, disclosed by the invention, is a preferable technical scheme that a decolorant filter cake obtained after the decoloration and filtration in item ② is washed by solvent acetic acid, and the washing is carried out by using industrial acetic acid with the solvent acetic acid content of more than or equal to 95 wt% or recycling acetic acid.
The refining and purifying method of the dodecyl dicarboxylic acid with high yield and low cost, disclosed by the invention, is characterized in that a decolorant filter cake obtained after the decoloration and filtration in item ② is washed by a solvent acetic acid, and the solvent acetic acid for washing is hot acetic acid with the temperature of 80-95 ℃, and is the most preferable technical scheme.
The invention relates to a refining and purifying method of dodecyl dicarboxylic acid with high yield and low cost, wherein the elutriation and crystallization process in item ③ comprises the steps of firstly adding deionized water into crystallization mother liquor under stirring, controlling the volume ratio of the mother liquor to the deionized water to be 1: 0.5-1, elutriating and crystallizing for 30-60 minutes under stirring to crystallize and separate out a long carbon chain dicarboxylic acid product dissolved in an acetic acid solvent, then filtering and separating by using a plate and frame filter press, combining the dodecyl dicarboxylic acid crystal with the filter cake content of 65-80 wt% obtained in the filter press with the crystal obtained by primary recrystallization, and carrying out subsequent leaching and drying steps together to obtain a dodecyl dicarboxylic acid main product, and the method is an optimal technical scheme.
The method for refining and purifying the dodecyl dicarboxylic acid with high yield and low cost, disclosed by the invention, is a preferable technical scheme that deionized water added into a crystallization mother liquor in the elutriation and crystallization process in item ③ is water-phase leaching filtrate generated in a water-phase leaching step in the refining and purifying process of the dodecyl dicarboxylic acid.
The invention relates to a method for refining and purifying dodecyl dicarboxylic acid with high yield and low cost, which recovers the solvent in the filtered mother liquor after the water precipitation and crystallization in ④, and the operating method of the azeotropic distillation process is as follows:
the method comprises the steps of enabling filtered mother liquor after water separation crystallization treatment to enter an azeotropic distillation system, enabling an entrainer to be sec-butyl acetate preferably, collecting sec-butyl acetate-water azeotrope from the top of a distillation process tower at 85-95 ℃ in a gas phase mode, enabling the azeotrope to enter a phase splitter for layering after condensation, collecting a lower-layer water phase as water for water separation crystallization feeding in ① for recycling, enabling an upper-layer sec-butyl acetate phase to flow back to an azeotropic distillation kettle to participate in azeotropic distillation continuously, enabling the temperature of the upper-layer sec-butyl acetate phase to be controlled at 110-125 ℃ to collect acetic acid, collecting the acetic acid with the content being larger than or equal to 95 wt% after cooling and heating, enabling the acetic acid to be used as an acetic acid solvent for recycling at a long-carbon-chain binary acid crude product dissolution and decoloration working section, and controlling the material temperature of the azeotropic distillation kettle at 100-135 ℃ to.
The method for refining and purifying the dodecyl dicarboxylic acid with high yield and low cost comprises the following operation steps:
first step, dissolving and decolorizing
At room temperature, putting a crude dodecyl dicarboxylic acid crude product with the water content of less than or equal to 20 wt%, acetic acid and activated carbon into a decoloring reaction kettle, heating the materials in the decoloring kettle to 90-95 ℃ under stirring, preserving the heat for 10-30 minutes, filtering, performing solid-liquid separation, and feeding the filtrate into a crystallization kettle for crystallization; washing a decolorant filter cake obtained after decoloration and filtration by using hot acetic acid with the content of more than or equal to 95 wt% and the temperature of 80-95 ℃, feeding the obtained decolorant filter cake washing liquid into a crystallization kettle, and completing a subsequent cooling crystallization process together with the decolored filtrate so as to recover dodecyl dicarboxylic acid carried in decolorant activated carbon;
second, cooling and crystallizing
Putting the filtrate decolored in the first step into a crystallization kettle, and carrying out gradient cooling crystallization under stirring:
① first stage cooling
In a crystallization kettle, stirring, starting an interlayer cooling water, and cooling the decolorized filtrate from step ① to 75-80 ℃;
② two-stage cooling and induced crystallization
Stirring, naturally cooling to 71-75 ℃, adding long carbon chain dibasic acid to induce seed crystal, and then continuously naturally cooling to 68-70 ℃;
③ three-stage cooling
Opening the interlayer cooling water, adjusting the flow rate of the cooling water, and cooling the temperature of the crystallization feed liquid to 20-30 ℃ until the crystallization is complete;
④, centrifuging and filtering;
centrifuging and filtering the completely crystallized material from item ③, washing the filter cake, and separating out the crystal from the mother liquor;
third step, water precipitation crystallization
Putting the mother solution generated by centrifugal filtration in the second step ④ into a water precipitation crystallization kettle, adding deionized water under stirring, or adding water phase leaching filtrate generated in the water phase leaching process in the fourth step ②, wherein the addition amount of the water phase leaching filtrate is controlled to be 1: 0.5-1, heating to 85-95 ℃ under stirring, then cooling to 25-30 ℃, performing water precipitation crystallization for 30-60 minutes, so that a long carbon chain dicarboxylic acid product dissolved in an acetic acid solvent is crystallized and separated out, then performing filtration and separation by using a plate and frame filter press, mixing the filter cake obtained in the filter press with 65-80 wt% of dodecyl dicarboxylic acid crystal, and performing subsequent washing and drying steps together to obtain a dodecyl dicarboxylic acid main product;
the fourth step, crystal washing
① acetic acid Leaching
Crystallizing the dodecyl dicarboxylic acid after the centrifugal separation in the second step and the third step, and leaching in a centrifugal machine by using a small amount of acetic acid, wherein the leaching amount of the acetic acid is 5-100% of that of the acetic acid for dissolution and decoloration in the first step; centrifugate produced in the leaching process is used as a solvent in the next batch feeding step of the production cycle; the filter cake after being dried is left in a centrifuge for preparing water phase for leaching;
② rinsing with water phase
Washing the filter cake in the centrifuge with deionized water or room temperature water washing filtrate generated in the subsequent ③ items, centrifuging and spin-drying again, and washing the filter cake with room temperature water;
③ washing with water at room temperature, and centrifuging
The filter cake from item ② is made into slurry by deionized water and then is sent into a water washing tank, the deionized water accounts for 70-120 percent of the mass of acetic acid used in the dissolving and decoloring step in the first step, the mixture is stirred and washed for 30 minutes in the water washing tank, centrifugal filtration is carried out, solid-liquid separation is carried out, the filter cake is ready for drying, the room-temperature water washing filtrate is sent into a room-temperature water washing filtrate storage tank and is ready for being used as water for water phase leaching in item ② in the fourth step of next batch production for recycling;
⑤ drying
Drying the filter cake from ③ items to obtain refined dodecyl dicarboxylic acid, wherein the refined and purified dodecyl dicarboxylic acid achieves the following technical indexes:
the refining and purifying yield of the dodecyl dicarboxylic acid is more than or equal to 96.00 percent.
Compared with the prior art, the technical scheme disclosed by the method for refining and purifying the dodecyl dicarboxylic acid, which is high in yield and low in cost, can produce the following positive effects:
1. provides a refining and purifying method of dodecyl dicarboxylic acid with high product yield, lower refining cost and high purity.
2. The method avoids the defects that in the prior art, after the crystallization mother liquor is subjected to solvent recovery, the obtained heavy component is repeatedly recycled and reused as a refined and purified raw material, so that the accumulation of other mixed dibasic acid and other impurities generated in the fermentation process influences the product quality of the dodecyl dicarboxylic acid.
3. Washing the decolorant filter cake obtained after decoloring and filtering with a solvent acetic acid, combining the obtained decolorant filter cake washing liquid and the decolorant filtering filtrate, and entering a subsequent cooling and crystallization process, thereby successfully recovering the dodecyl dicarboxylic acid carried in the decolorant activated carbon. The technical scheme that the raw material long-chain dibasic acid crude product for refining and purification directly enters the subsequent decoloring technological process without drying treatment is implemented, and the problem that the dicarboxylic acid loss is caused by the fact that long-carbon-chain dibasic acid crystals enter a filter cake along with activated carbon in the prior art, and thus the dicarboxylic acid refining and purification yield is reduced is solved.
4. Before the solvent is recovered from the recrystallization mother liquor, firstly, water is separated out for crystallization, and the dodecyl dicarboxylic acid product dissolved in the crystallization mother liquor is extracted again. Solves the technical problem that the target dicarboxylic acid main product dissolved in the crystallization mother liquor is completely produced and sold as the long carbon chain mixed dicarboxylic acid by-product in the prior art.
5. The method comprises the steps of recovering a solvent in a filtered mother liquor after water separation crystallization, recycling the solvent by adopting an azeotropic distillation method, selecting sec-butyl acetate as an entrainer, separating water from acetic acid through an azeotropic distillation process, using the separated water as water for water separation crystallization feeding in characteristic ③, recycling the water, and using the separated solvent acetic acid as the solvent for recycling in a refining and purifying process of dodecyl dicarboxylic acid.
6. The refined and purified dodecyl dicarboxylic acid achieves the following technical indexes:
the refining and purifying yield of the dodecyl dicarboxylic acid is more than or equal to 96.00 percent.
Detailed Description
The invention will be further described in detail with reference to the following examples:
example 1 a process for the purification and purification of dodecanedicarboxylic acid according to the present invention with high yield and low cost comprises the following steps:
first step, dissolving and decolorizing
Putting 1000Kg of dodecane dicarboxylic acid crude product with dodecane dicarboxylic acid content of 80% by mass, 2000L of 95 wt% industrial acetic acid and 6Kg of activated carbon into a decoloring reaction kettle at room temperature, heating materials in the decoloring kettle to 95 ℃ under stirring, preserving heat for 20 minutes, filtering, performing solid-liquid separation, and feeding filtrate into a crystallization kettle for crystallization; and (3) washing a decolorant filter cake obtained after decoloring and filtering by using hot acetic acid with the content of more than or equal to 95 wt% and the temperature of 80 ℃, feeding the obtained decolorant filter cake washing liquid into a crystallization kettle, and completing a subsequent cooling crystallization process together with the decolored filtrate so as to recover dodecanedicarboxylic acid carried in the decolorant activated carbon.
Second, cooling and crystallizing
And (3) putting the filtrate subjected to the first-step decolorization into a crystallization kettle, stirring, and performing gradient cooling crystallization.
① first stage cooling
In a crystallization kettle, stirring, starting an interlayer cooling water, cooling the decolorized filtrate from the first step to 78 ℃, and closing the cooling water.
② two-stage cooling and induced crystallization
And (3) naturally cooling to 75 ℃ under stirring, adding dodecane dicarboxylic acid with the purity of more than 99.8 percent as seed crystal, controlling the stirring speed to be 40r/min, rebounding the temperature in the crystallization kettle to be 77 ℃, and then gradually reducing. The temperature naturally dropped to 68 ℃.
③ three-stage cooling
Opening the interlayer cooling water, adjusting the flow rate of the cooling water, controlling the cooling speed from slow to fast, and finally cooling to 25 ℃ until the crystallization is complete.
The whole cooling crystallization time is controlled to be 6-8 hours.
④, centrifuging and filtering;
the completely crystallized material from item ③ above was centrifuged, the cake was rinsed, and the mother liquor was crystallized by water precipitation.
Third step, water precipitation crystallization
Putting the mother liquor generated by centrifugal filtration in the second step ④ into a water precipitation crystallization kettle, adding 2000L of deionized water, stirring, heating to 85 ℃, then cooling to 25 ℃, performing water precipitation crystallization for 30-60 minutes to separate out crystals of the dodecanedicarboxylic acid product dissolved in the acetic acid solvent, filtering and separating by using a plate-and-frame filter press, mixing the 102.28Kg of dodecanedicarboxylic acid crystals obtained in the filter press and the crystals obtained by the second step of cooling crystallization, and performing subsequent washing and drying steps to jointly obtain a dodecanedicarboxylic acid main product;
the fourth step, crystal washing
① acetic acid Leaching
Merging the dodecane dicarboxylic acid crystals after centrifugal separation in the second step and the third step, leaching in a centrifuge by using 200L of 98 wt% acetic acid, and centrifuging for 15 minutes after leaching is finished; centrifugate produced in the leaching process is used as a solvent in the next batch feeding step of the production cycle; the filter cake after being dried is left in a centrifuge for preparing water phase for leaching;
② rinsing with water phase
Leaching a filter cake in a centrifuge by 2000L of deionized water, centrifuging and drying for 15 minutes, and washing the filter cake at room temperature; sending the water-phase leaching filtrate generated in the water-phase leaching process into a water-phase leaching filtrate storage tank for use in place of deionized water in the third step of a water separation crystallization process;
③ washing with water at room temperature, and centrifuging
Making 1200L of deionized water into slurry from ② filter cakes, sending the slurry into a water washing tank, adding 800L of deionized water into the water washing tank, stirring and washing for 30 minutes, performing centrifugal filtration, performing solid-liquid separation, and drying the filter cakes;
⑤ drying
And drying the filter cake from ③ items to obtain 768Kg of refined dodecanedicarboxylic acid, wherein the refined and purified dodecanedicarboxylic acid reaches the following technical indexes:
the refining and purifying yield of the dodecanedicarboxylic acid is 96.00 percent.
Example 2. the refining and purifying method of dodecanedicarboxylic acid of the present invention with high yield and low cost comprises the following steps:
first step, dissolving and decolorizing
At room temperature, 940Kg of crude dodecanedicarboxylic acid with the dodecanedicarboxylic acid mass percentage content of 80.8%, 200L of centrifugate generated in the acetic acid leaching process of ① items of crystal washing in the step 4 of the embodiment 1, 1800L of industrial acetic acid with the weight percentage content of 95% and 6Kg of active carbon are put into a decoloring reaction kettle, materials in the decoloring kettle are heated to 90 ℃ under stirring, the temperature is kept for 30 minutes, the materials are filtered, solid-liquid separation is carried out, filtrate is sent into a crystallization kettle for crystallization, decoloring agent filter cake obtained after decoloring and filtering is washed by hot acetic acid with the content of more than or equal to 95% and the temperature of 95 ℃, decoloring agent filter cake washing liquid is also sent into the crystallization kettle, and the decoloring agent filter cake washing liquid and the decolored filtrate complete the subsequent cooling and crystallizing process together to recover the dodecanedicarboxylic acid carried in the decoloring agent active.
Second, cooling and crystallizing
And (3) putting the filtrate subjected to the first-step decolorization into a crystallization kettle, stirring, and performing gradient cooling crystallization.
① first stage cooling
In a crystallization kettle, stirring, starting an interlayer cooling water, cooling the decolorized filtrate from the first step to 77 ℃, and closing the cooling water.
② two-stage cooling and induced crystallization
And (3) naturally cooling to 73 ℃ under stirring, adding dodecanedicarboxylic acid with the purity of more than 99.8 percent as seed crystal, controlling the stirring speed to be 40r/min, rebounding the temperature in the crystallization kettle to be 75 ℃, and then gradually reducing. The temperature naturally drops to 70 ℃.
③ three-stage cooling
Opening the interlayer cooling water, adjusting the flow rate of the cooling water, controlling the cooling speed from slow to fast, and finally cooling to 30 ℃ until the crystallization is complete.
The whole cooling crystallization time is controlled to be 6-8 hours.
④, centrifuging and filtering;
the completely crystallized material from item ③ above was centrifuged, the cake was rinsed, and the mother liquor was crystallized by water precipitation.
Third step, water precipitation crystallization
Putting the mother liquor generated by centrifugal filtration in the second step ④ into a water precipitation crystallization kettle, adding 2000L of water phase leaching filtrate generated in the water phase leaching process in the fourth step ② in the embodiment 1, stirring, heating to 95 ℃, then cooling to 30 ℃, performing water precipitation crystallization for 30-60 minutes to separate out dodecanedicarboxylic acid product crystals dissolved in an acetic acid solvent, filtering and separating by using a plate and frame filter press, mixing 98Kg of dodecanedicarboxylic acid crystals obtained in the filter press and crystals obtained by the second step of cooling crystallization, and performing subsequent washing and drying steps to jointly obtain a dodecanedicarboxylic acid main product;
the fourth step, crystal washing
① acetic acid Leaching
Merging the dodecane dicarboxylic acid crystals after centrifugal separation in the second step and the third step, leaching in a centrifuge by using 300L of 98 wt% acetic acid, and centrifuging for 15 minutes after leaching is finished; centrifugate produced in the leaching process is used as a solvent in the next batch feeding step of the production cycle; the filter cake after being dried is left in a centrifuge for preparing water phase for leaching;
② rinsing with water phase
Washing a filter cake in a centrifuge by 2000L of room-temperature water washing filtrate generated in the fourth step ③ in example 1, centrifuging and spin-drying for 15 minutes, washing the filter cake by room-temperature water, sending water-phase washing filtrate generated in the water-phase washing process into a water-phase washing filtrate storage tank, and using the water-phase washing filtrate in the third step of a water separation crystallization process to replace deionized water;
③ washing with water at room temperature, and centrifuging
Making 1200L of deionized water into slurry from ② filter cakes, sending the slurry into a water washing tank, adding 800L of deionized water into the water washing tank, stirring and washing for 30 minutes, performing centrifugal filtration, performing solid-liquid separation, and drying the filter cakes;
⑤ drying
The filter cake from ③ is dried to obtain 730.66Kg of refined dodecanedicarboxylic acid, and the refined and purified dodecanedicarboxylic acid reaches the following technical indexes:
the refining and purifying yield of the dodecanedicarboxylic acid is 96.20 percent.
Example 3. the refining and purifying method of dodecanedioic acid of the invention with high yield and low cost comprises the following steps:
first step, dissolving and decolorizing
At room temperature, putting 805Kg of crude dodecyl dicarboxylic acid with 82.0 percent of dodecyl dicarboxylic acid by mass, 2000L of 95 percent of industrial acetic acid by mass and 6Kg of active carbon into a decoloring reaction kettle, heating the materials in the decoloring kettle to 92 ℃ under stirring, preserving the temperature for 10 minutes, filtering, carrying out solid-liquid separation, and sending the filtrate into a crystallization kettle for crystallization; and (3) washing a decolorant filter cake obtained after decoloring and filtering by using hot acetic acid with the content of more than or equal to 95 wt% and the temperature of 90 ℃, feeding the obtained decolorant filter cake washing liquid into a crystallization kettle, and completing a subsequent cooling crystallization process together with the decolored filtrate so as to recover the dodecyl dicarboxylic acid carried in the decolorant activated carbon.
Second, cooling and crystallizing
And (3) putting the filtrate subjected to the first-step decolorization into a crystallization kettle, stirring, and performing gradient cooling crystallization.
① first stage cooling
In a crystallization kettle, stirring, starting an interlayer cooling water, cooling the decolorized filtrate from the first step to 77 ℃, and closing the cooling water.
② two-stage cooling and induced crystallization
And (3) naturally cooling to 71 ℃ under stirring, adding dodecyl dicarboxylic acid with the purity of more than 99.8 percent as seed crystal, controlling the stirring speed to be 40r/min, rebounding the temperature in the crystallization kettle to 72-73 ℃, and then gradually reducing. The temperature naturally dropped to 69 ℃.
③ three-stage cooling
Opening the interlayer cooling water, adjusting the flow rate of the cooling water, controlling the cooling speed from slow to fast, and finally cooling to 27 ℃ until the crystallization is complete.
The whole cooling crystallization time is controlled to be 6-8 hours.
④, centrifuging and filtering;
the completely crystallized material from item ③ above was centrifuged, the cake was rinsed, and the mother liquor was crystallized by water precipitation.
Third step, water precipitation crystallization
Putting the mother liquor generated by the centrifugal filtration in the second step ④ into a water precipitation crystallization kettle, adding 2000L of deionized water, heating to 90 ℃ under stirring, then cooling to 27 ℃ for water precipitation crystallization for 30-60 minutes to separate out the dodecyl dicarboxylic acid product dissolved in the acetic acid solvent, filtering and separating by using a plate and frame filter press, wherein the filter cake obtained in the filter press is 101.3Kg of dodecyl dicarboxylic acid crystals, and combining with the crystals obtained by the cooling crystallization in the second step, and then performing subsequent washing and drying steps to jointly prepare the dodecyl dicarboxylic acid main product;
the fourth step, crystal washing
① acetic acid Leaching
Merging the dodecyl dicarboxylic acid crystals after the centrifugal separation in the second step and the third step, leaching in a centrifuge by 200L of 98 wt% acetic acid, and centrifuging for 15 minutes after leaching; centrifugate produced in the leaching process is used as a solvent in the next batch feeding step of the production cycle; the filter cake after being dried is left in a centrifuge for preparing water phase for leaching;
② rinsing with water phase
Leaching a filter cake in a centrifuge by 2000L of deionized water, centrifuging and drying for 15 minutes, and washing the filter cake at room temperature; sending the water-phase leaching filtrate generated in the water-phase leaching process into a water-phase leaching filtrate storage tank for use in place of deionized water in the third step of a water separation crystallization process;
③ washing with water at room temperature, and centrifuging
Making 1200L of deionized water into slurry from ② filter cakes, sending the slurry into a water washing tank, adding 800L of deionized water into the water washing tank, stirring and washing for 30 minutes, performing centrifugal filtration, performing solid-liquid separation, and drying the filter cakes;
⑤ drying
The filter cake from ③ is dried to obtain 634.3Kg of refined dodecyl dicarboxylic acid, and the refined and purified dodecyl dicarboxylic acid reaches the following technical indexes:
the refining and purifying yield of the dodecyl dicarboxylic acid is 96.09%.
Example 4. the refining and purifying method of dodecanedioic acid of the present invention with high yield and low cost comprises the following steps:
first step, dissolving and decolorizing
At room temperature, putting 800Kg of a dodecyl dicarboxylic acid crude product with the mass percentage of 85 percent of dodecyl dicarboxylic acid, 2000L of 95 weight percent of industrial acetic acid and 6Kg of active carbon into a decoloring reaction kettle, heating the materials in the decoloring kettle to 93 ℃ under stirring, preserving the temperature for 15 minutes, filtering, performing solid-liquid separation, and sending the filtrate into a crystallization kettle for crystallization; and (3) washing a decolorant filter cake obtained after decoloring and filtering by using hot acetic acid with the content of more than or equal to 95 wt% and the temperature of 85 ℃, feeding the obtained decolorant filter cake washing liquid into a crystallization kettle, and completing a subsequent cooling crystallization process together with the decolored filtrate so as to recover the dodecyl dicarboxylic acid carried in the decolorant activated carbon.
Second, cooling and crystallizing
And (3) putting the filtrate subjected to the first-step decolorization into a crystallization kettle, stirring, and performing gradient cooling crystallization.
① first stage cooling
In a crystallization kettle, stirring, starting an interlayer cooling water, cooling the decolorized filtrate from the first step to 80 ℃, and closing the cooling water.
② two-stage cooling and induced crystallization
Naturally cooling to 72 ℃ under stirring, adding dodecyl dicarboxylic acid with the purity of more than 99.8 percent as seed crystal, controlling the stirring speed to be 40r/min, rebounding the temperature in the crystallization kettle to 74 ℃, and then gradually reducing. The temperature naturally dropped to 68 ℃.
③ three-stage cooling
Opening the interlayer cooling water, adjusting the flow rate of the cooling water, controlling the cooling speed from slow to fast, and finally cooling to 28 ℃ until the crystallization is complete.
The whole cooling crystallization time is controlled to be 6-8 hours.
④, centrifuging and filtering;
the completely crystallized material from item ③ above was centrifuged, the cake was rinsed, and the mother liquor was crystallized by water precipitation.
Third step, water precipitation crystallization
Putting the mother liquor generated by the centrifugal filtration in the second step ④ into a water precipitation crystallization kettle, adding 2000L of deionized water, stirring, heating to 88 ℃, then cooling to 28 ℃, performing water precipitation crystallization for 30-60 minutes to separate out the crystals of the dodecyl dicarboxylic acid product dissolved in the acetic acid solvent, filtering and separating by using a plate and frame filter press, mixing the filter cake obtained in the filter press with 99.2Kg of dodecyl dicarboxylic acid crystals and the crystals obtained by the temperature reduction crystallization in the second step, and performing subsequent washing and drying steps to jointly prepare a dodecyl dicarboxylic acid main product;
the fourth step, crystal washing
① acetic acid Leaching
Merging the dodecyl dicarboxylic acid crystals after the centrifugal separation in the second step and the third step, leaching in a centrifuge by using 300L of 98 wt% acetic acid, and centrifuging for 15 minutes after leaching; centrifugate produced in the leaching process is used as a solvent in the next batch feeding step of the production cycle; the filter cake after being dried is left in a centrifuge for preparing water phase for leaching;
② rinsing with water phase
Leaching a filter cake in a centrifuge by 2000L of deionized water, centrifuging and drying for 15 minutes, and washing the filter cake at room temperature; sending the water-phase leaching filtrate generated in the water-phase leaching process into a water-phase leaching filtrate storage tank for use in place of deionized water in the third step of a water separation crystallization process;
③ washing with water at room temperature, and centrifuging
Making 1200L of deionized water into slurry from ② filter cakes, sending the slurry into a water washing tank, adding 800L of deionized water into the water washing tank, stirring and washing for 30 minutes, performing centrifugal filtration, performing solid-liquid separation, and drying the filter cakes;
⑤ drying
The filter cake from ③ is dried to obtain 653.5Kg of refined dodecyl dicarboxylic acid, and the refined and purified dodecyl dicarboxylic acid reaches the following technical indexes:
the refining and purifying yield of the dodecyl dicarboxylic acid is 96.10 percent.
Example 5. the refining and purifying method of dodecanedioic acid of the invention with high yield and low cost comprises the following steps:
first step, dissolving and decolorizing
Putting 975Kg of a crude product of 80 mass percent of dodecyl dicarboxylic acid, 2000L of 95 weight percent of industrial acetic acid and 6Kg of active carbon into a decoloring reaction kettle at room temperature, heating the materials in the decoloring reaction kettle to 94 ℃ under stirring, preserving the temperature for 25 minutes, filtering, performing solid-liquid separation, and feeding the filtrate into a crystallization kettle for crystallization; and (3) washing a decolorant filter cake obtained after decoloring and filtering by using hot acetic acid with the content of more than or equal to 95 wt% and the temperature of 93 ℃, feeding the obtained decolorant filter cake washing liquid into a crystallization kettle, and completing a subsequent cooling crystallization process together with the decolored filtrate so as to recover the dodecyl dicarboxylic acid carried in the decolorant activated carbon.
Second, cooling and crystallizing
And (3) putting the filtrate subjected to the first-step decolorization into a crystallization kettle, stirring, and performing gradient cooling crystallization.
① first stage cooling
In a crystallization kettle, stirring, starting an interlayer cooling water, cooling the decolorized filtrate from the first step to 76 ℃, and closing the cooling water.
② two-stage cooling and induced crystallization
And (3) naturally cooling to 74 ℃ under stirring, adding dodecyl dicarboxylic acid with the purity of more than 99.8 percent as seed crystal, controlling the stirring speed to be 40r/min, rebounding the temperature in the crystallization kettle to 76 ℃, and then gradually reducing. The temperature naturally drops to 70 ℃.
③ three-stage cooling
Opening the interlayer cooling water, adjusting the flow rate of the cooling water, controlling the cooling speed from slow to fast, and finally cooling to 25 ℃ until the crystallization is complete.
The whole cooling crystallization time is controlled to be 6-8 hours.
④, centrifuging and filtering;
the completely crystallized material from item ③ above was centrifuged, the cake was rinsed, and the mother liquor was crystallized by water precipitation.
Third step, water precipitation crystallization
Putting the mother liquor generated by centrifugal filtration in the second step ④ into a water precipitation crystallization kettle, adding 2000L of deionized water, stirring, heating to 92 ℃, then cooling to 25 ℃, performing water precipitation crystallization for 30-60 minutes to separate out the crystals of the dodecyl dicarboxylic acid product dissolved in the acetic acid solvent, filtering and separating by using a plate and frame filter press, mixing the 101.5Kg of dodecyl dicarboxylic acid crystals with the crystals obtained by the second step of cooling crystallization, and performing subsequent washing and drying steps to jointly prepare a dodecyl dicarboxylic acid main product;
the fourth step, crystal washing
① acetic acid Leaching
Merging the dodecyl dicarboxylic acid crystals after the centrifugal separation in the second step and the third step, leaching in a centrifuge by 200L of 98 wt% acetic acid, and centrifuging for 15 minutes after leaching; centrifugate produced in the leaching process is used as a solvent in the next batch feeding step of the production cycle; the filter cake after being dried is left in a centrifuge for preparing water phase for leaching;
② rinsing with water phase
Leaching a filter cake in a centrifuge by 2000L of deionized water, centrifuging and drying for 15 minutes, and washing the filter cake at room temperature; sending the water-phase leaching filtrate generated in the water-phase leaching process into a water-phase leaching filtrate storage tank for use in place of deionized water in the third step of a water separation crystallization process;
③ washing with water at room temperature, and centrifuging
Making 1200L of deionized water into slurry from ② filter cakes, sending the slurry into a water washing tank, adding 800L of deionized water into the water washing tank, stirring and washing for 30 minutes, performing centrifugal filtration, performing solid-liquid separation, and drying the filter cakes;
⑤ drying
The filter cake from ③ is dried to obtain 751.4Kg of refined dodecyl dicarboxylic acid, and the refined and purified dodecyl dicarboxylic acid reaches the following technical indexes:
the refining and purifying yield of the dodecyl dicarboxylic acid is 96.33.
Claims (8)
1. A method for refining and purifying dodecyl dicarboxylic acid with high yield and low cost is characterized in that: the method comprises the following steps of taking a crude dodecyl dicarboxylic acid product prepared by a fermentation method as a raw material, taking acetic acid as a solvent, refining and purifying the raw material by recrystallization, decoloring, filtering, cooling, crystallizing, centrifuging, washing a filter cake, and drying to obtain a dodecyl dicarboxylic acid product, recycling the solvent from a recrystallization mother liquor, mixing the obtained heavy component with the crude dodecyl dicarboxylic acid product, and recycling the heavy component as a refined and purified raw material, wherein the method comprises the following steps:
①, the raw material dodecyl dicarboxylic acid crude product for refining and purification is directly fed into the subsequent decoloring process without drying treatment;
②, washing the decolorant filter cake obtained after decoloration and filtration with a solvent acetic acid, and combining the obtained decolorant filter cake washing liquid and the decolorant filtration filtrate to enter a subsequent cooling crystallization process so as to recover the dodecyl dicarboxylic acid carried in the decolorant activated carbon;
③, before recovering the solvent, the recrystallization mother liquor firstly elutes and crystallizes, and then extracts the dodecyl dicarboxylic acid product dissolved in the crystallization mother liquor, wherein the elutriation crystallization is to add deionized water into the crystallization mother liquor to crystallize and separate the dodecyl dicarboxylic acid product dissolved in the acetic acid solvent, then the filtration and the separation are carried out, the obtained dodecyl dicarboxylic acid crystal is combined with the crystal obtained by the first recrystallization, and the combined crystal and the crystal are subjected to the subsequent leaching and drying processes to jointly prepare the dodecyl dicarboxylic acid product;
④ recovering solvent from the filtered mother liquid after water separation and crystallization, recovering and utilizing by azeotropic distillation, the entrainer is sec-butyl acetate, separating water from acetic acid by azeotropic distillation process, the separated water is used as water for water separation and crystallization in ③, and the separated solvent acetic acid is used as solvent in the refining and purification process of dodecyl dicarboxylic acid.
2. The process according to claim 1, wherein ① said crude dodecanedioic acid to be purified is C12The normal alkane is used as raw material, fermentation liquor prepared by microbial fermentation is filtered, decolored, acidified, crystallized and filtered to obtain filter cake crystals, the water content of the filter cake crystals is less than or equal to 20 wt%, and the filter cake crystals are directly used as refined raw materials without being dried.
3. The process according to claim 1, wherein the decolorizer cake obtained by the decolorizing and filtering in item ② is washed with acetic acid as a solvent, and the washing is carried out with industrial acetic acid containing acetic acid as a solvent in an amount of 95 wt% or more or recovered acetic acid.
4. The method for refining and purifying dodecanedicarboxylic acid with high yield and low cost according to claim 1, wherein a decolorizer filter cake obtained after the decolorization and filtration in item ② is washed with a solvent acetic acid, and the solvent acetic acid for washing is hot acetic acid at 80-95 ℃.
5. The refining and purifying method of dodecyl dicarboxylic acid with high yield and low cost according to claim 1 is characterized in that ③ items of the water precipitation crystallization process include the steps of firstly adding deionized water into crystallization mother liquor under stirring, controlling the volume ratio of the mother liquor to the deionized water to be 1: 0.5-1, conducting water precipitation crystallization for 30-60 minutes under stirring to crystallize and separate out long carbon chain dicarboxylic acid products dissolved in an acetic acid solvent, then adopting a plate and frame filter press for filtration and separation, merging 65-80 wt% of dodecyl dicarboxylic acid crystals and crystals obtained by primary recrystallization to obtain a filter cake in the filter press, and conducting subsequent leaching and drying steps together to obtain a dodecyl dicarboxylic acid main product;
6. the method according to claim 1 or claim 5, wherein the deionized water added to the mother liquid during the water crystallization process of item ③ is the aqueous leaching filtrate generated in the aqueous leaching step of the purification process.
7. The process according to claim 1, wherein the azeotropic distillation is carried out in the recovery of the solvent from the filtered mother liquor after the water separation and crystallization in ④:
the method comprises the steps of enabling filtered mother liquor after water separation crystallization treatment to enter an azeotropic distillation system, enabling an entrainer to be sec-butyl acetate preferably, collecting sec-butyl acetate-water azeotrope from the top of a distillation process tower at 85-95 ℃ in a gas phase mode, enabling the azeotrope to enter a phase splitter for layering after condensation, collecting a lower-layer water phase as water for water separation crystallization feeding in ① for recycling, enabling an upper-layer sec-butyl acetate phase to flow back to an azeotropic distillation kettle to participate in azeotropic distillation continuously, enabling the temperature of the upper-layer sec-butyl acetate phase to be controlled at 110-125 ℃ to collect acetic acid, collecting the acetic acid with the content being more than or equal to 95 wt% after cooling and heating, enabling the acetic acid to be used as an acetic acid solvent for recycling at a long-carbon-chain binary acid crude product dissolution and decoloration working section, and controlling the material temperature of the azeotropic distillation kettle.
8. The method for refining and purifying dodecyl dicarboxylic acid with high yield and low cost as claimed in claim 1, which comprises the following steps:
first step, dissolving and decolorizing
At room temperature, putting a crude dodecyl dicarboxylic acid crude product with the water content of less than or equal to 20 wt%, acetic acid and activated carbon into a decoloring reaction kettle, heating the materials in the decoloring kettle to 90-95 ℃ under stirring, preserving the heat for 10-30 minutes, filtering, performing solid-liquid separation, and feeding the filtrate into a crystallization kettle for crystallization; washing a decolorant filter cake obtained after decoloration and filtration by using hot acetic acid with the content of more than or equal to 95 wt% and the temperature of 80-95 ℃, feeding the obtained decolorant filter cake washing liquid into a crystallization kettle, and completing a subsequent cooling crystallization process together with the decolored filtrate so as to recover dodecyl dicarboxylic acid carried in decolorant activated carbon;
second, cooling and crystallizing
Putting the filtrate decolored in the first step into a crystallization kettle, and carrying out gradient cooling crystallization under stirring:
① first stage cooling
In a crystallization kettle, stirring, starting an interlayer cooling water, and cooling the decolorized filtrate from step ① to 75-80 ℃;
② two-stage cooling and induced crystallization
Stirring, naturally cooling to 71-75 ℃, adding long carbon chain dibasic acid to induce seed crystal, and then continuously naturally cooling to 68-70 ℃;
③ three-stage cooling
Opening the interlayer cooling water, adjusting the flow rate of the cooling water, and cooling the temperature of the crystallization feed liquid to 20-30 ℃ until the crystallization is complete;
④, centrifuging and filtering;
centrifuging and filtering the completely crystallized material from item ③, washing the filter cake, and separating out the crystal from the mother liquor;
third step, water precipitation crystallization
Putting the mother solution generated by centrifugal filtration in the second step ④ into a water precipitation crystallization kettle, adding deionized water under stirring, or adding water phase leaching filtrate generated in the water phase leaching process in the fourth step ②, wherein the addition amount of the water phase leaching filtrate is controlled to be 1: 0.5-1, heating to 85-95 ℃ under stirring, then cooling to 25-30 ℃, performing water precipitation crystallization for 30-60 minutes, so that a long carbon chain dicarboxylic acid product dissolved in an acetic acid solvent is crystallized and separated out, then performing filtration and separation by using a plate and frame filter press, mixing the filter cake obtained in the filter press with 65-80 wt% of dodecyl dicarboxylic acid crystal, and performing subsequent washing and drying steps together to obtain a dodecyl dicarboxylic acid main product;
the fourth step, crystal washing
① acetic acid Leaching
Crystallizing the dodecyl dicarboxylic acid after the centrifugal separation in the second step and the third step, and leaching in a centrifugal machine by using a small amount of acetic acid, wherein the leaching amount of the acetic acid is 5-100% of that of the acetic acid for dissolution and decoloration in the first step; centrifugate produced in the leaching process is used as a solvent in the next batch feeding step of the production cycle; the filter cake after being dried is left in a centrifuge for preparing water phase for leaching;
② rinsing with water phase
Washing the filter cake in the centrifuge with deionized water or room temperature water washing filtrate generated in the subsequent ③ items, centrifuging and spin-drying again, and washing the filter cake with room temperature water;
③ washing with water at room temperature, and centrifuging
The filter cake from item ② is made into slurry by deionized water and then is sent into a water washing tank, the deionized water accounts for 70-120 percent of the mass of acetic acid used in the dissolving and decoloring step in the first step, the mixture is stirred and washed for 30 minutes in the water washing tank, centrifugal filtration is carried out, solid-liquid separation is carried out, the filter cake is ready for drying, the room-temperature water washing filtrate is sent into a room-temperature water washing filtrate storage tank and is ready for being used as water for water phase leaching in item ② in the fourth step of next batch production for recycling;
⑤ drying
Drying the filter cake from ③ items to obtain refined dodecyl dicarboxylic acid, wherein the refined and purified dodecyl dicarboxylic acid achieves the following technical indexes:
the refining and purifying yield of the dodecyl dicarboxylic acid is more than or equal to 96.00 percent.
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