CN116730866B - Preparation method of cyanoacetic acid - Google Patents
Preparation method of cyanoacetic acid Download PDFInfo
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- CN116730866B CN116730866B CN202311014337.3A CN202311014337A CN116730866B CN 116730866 B CN116730866 B CN 116730866B CN 202311014337 A CN202311014337 A CN 202311014337A CN 116730866 B CN116730866 B CN 116730866B
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- cyanoacetic acid
- sulfhydryl
- pretreatment
- sodium
- sodium chloride
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- MLIREBYILWEBDM-UHFFFAOYSA-N cyanoacetic acid Chemical compound OC(=O)CC#N MLIREBYILWEBDM-UHFFFAOYSA-N 0.000 title claims abstract description 268
- 238000002360 preparation method Methods 0.000 title claims abstract description 25
- 238000006243 chemical reaction Methods 0.000 claims abstract description 54
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 34
- JAUCIKCNYHCSIR-UHFFFAOYSA-M sodium;2-cyanoacetate Chemical compound [Na+].[O-]C(=O)CC#N JAUCIKCNYHCSIR-UHFFFAOYSA-M 0.000 claims abstract description 30
- 239000007788 liquid Substances 0.000 claims abstract description 22
- 238000000034 method Methods 0.000 claims abstract description 20
- 125000003396 thiol group Chemical group [H]S* 0.000 claims abstract description 18
- 239000000126 substance Substances 0.000 claims abstract description 15
- 230000002378 acidificating effect Effects 0.000 claims abstract description 13
- 230000018044 dehydration Effects 0.000 claims abstract description 11
- 238000006297 dehydration reaction Methods 0.000 claims abstract description 11
- 238000002156 mixing Methods 0.000 claims abstract description 5
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 35
- 230000020477 pH reduction Effects 0.000 claims description 32
- 238000000354 decomposition reaction Methods 0.000 claims description 19
- YXIWHUQXZSMYRE-UHFFFAOYSA-N 1,3-benzothiazole-2-thiol Chemical compound C1=CC=C2SC(S)=NC2=C1 YXIWHUQXZSMYRE-UHFFFAOYSA-N 0.000 claims description 16
- 238000001035 drying Methods 0.000 claims description 14
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims description 10
- -1 nitrogen heterocyclic compound Chemical class 0.000 claims description 10
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 8
- IJGRMHOSHXDMSA-UHFFFAOYSA-N nitrogen Substances N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 8
- 229910052757 nitrogen Inorganic materials 0.000 claims description 8
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 claims description 7
- 229910000041 hydrogen chloride Inorganic materials 0.000 claims description 7
- YHMYGUUIMTVXNW-UHFFFAOYSA-N 1,3-dihydrobenzimidazole-2-thione Chemical compound C1=CC=C2NC(S)=NC2=C1 YHMYGUUIMTVXNW-UHFFFAOYSA-N 0.000 claims description 5
- FLFWJIBUZQARMD-UHFFFAOYSA-N 2-mercapto-1,3-benzoxazole Chemical compound C1=CC=C2OC(S)=NC2=C1 FLFWJIBUZQARMD-UHFFFAOYSA-N 0.000 claims description 5
- BXDMTLVCACMNJO-UHFFFAOYSA-N 5-amino-1,3-dihydrobenzimidazole-2-thione Chemical compound NC1=CC=C2NC(S)=NC2=C1 BXDMTLVCACMNJO-UHFFFAOYSA-N 0.000 claims description 5
- CWIYBOJLSWJGKV-UHFFFAOYSA-N 5-methyl-1,3-dihydrobenzimidazole-2-thione Chemical compound CC1=CC=C2NC(S)=NC2=C1 CWIYBOJLSWJGKV-UHFFFAOYSA-N 0.000 claims description 5
- 229910000147 aluminium phosphate Inorganic materials 0.000 claims description 5
- WHMDPDGBKYUEMW-UHFFFAOYSA-N pyridine-2-thiol Chemical compound SC1=CC=CC=N1 WHMDPDGBKYUEMW-UHFFFAOYSA-N 0.000 claims description 5
- 239000012295 chemical reaction liquid Substances 0.000 claims description 4
- 239000002904 solvent Substances 0.000 claims description 4
- 230000035484 reaction time Effects 0.000 claims description 3
- 238000000926 separation method Methods 0.000 claims description 3
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 abstract description 112
- 239000011780 sodium chloride Substances 0.000 abstract description 56
- 150000001875 compounds Chemical class 0.000 abstract description 11
- 125000004093 cyano group Chemical group *C#N 0.000 abstract description 6
- 230000009286 beneficial effect Effects 0.000 abstract description 3
- 230000000269 nucleophilic effect Effects 0.000 abstract description 2
- 239000000758 substrate Substances 0.000 abstract description 2
- 239000000243 solution Substances 0.000 description 41
- 239000007864 aqueous solution Substances 0.000 description 24
- 239000007787 solid Substances 0.000 description 22
- 238000004090 dissolution Methods 0.000 description 20
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 description 19
- 238000010438 heat treatment Methods 0.000 description 19
- 239000008213 purified water Substances 0.000 description 19
- 238000003756 stirring Methods 0.000 description 19
- 239000011259 mixed solution Substances 0.000 description 11
- 239000000047 product Substances 0.000 description 10
- 230000000052 comparative effect Effects 0.000 description 5
- 238000001704 evaporation Methods 0.000 description 5
- 239000002994 raw material Substances 0.000 description 5
- 239000001488 sodium phosphate Substances 0.000 description 5
- 229910000162 sodium phosphate Inorganic materials 0.000 description 5
- RYFMWSXOAZQYPI-UHFFFAOYSA-K trisodium phosphate Chemical compound [Na+].[Na+].[Na+].[O-]P([O-])([O-])=O RYFMWSXOAZQYPI-UHFFFAOYSA-K 0.000 description 5
- 239000006227 byproduct Substances 0.000 description 4
- KXZJHVJKXJLBKO-UHFFFAOYSA-N chembl1408157 Chemical compound N=1C2=CC=CC=C2C(C(=O)O)=CC=1C1=CC=C(O)C=C1 KXZJHVJKXJLBKO-UHFFFAOYSA-N 0.000 description 4
- FOCAUTSVDIKZOP-UHFFFAOYSA-N chloroacetic acid Chemical compound OC(=O)CCl FOCAUTSVDIKZOP-UHFFFAOYSA-N 0.000 description 4
- 229940106681 chloroacetic acid Drugs 0.000 description 4
- 230000008020 evaporation Effects 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 238000003786 synthesis reaction Methods 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- PXQLVRUNWNTZOS-UHFFFAOYSA-N sulfanyl Chemical class [SH] PXQLVRUNWNTZOS-UHFFFAOYSA-N 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- RYYVLZVUVIJVGH-UHFFFAOYSA-N caffeine Chemical compound CN1C(=O)N(C)C(=O)C2=C1N=CN2C RYYVLZVUVIJVGH-UHFFFAOYSA-N 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 238000013375 chromatographic separation Methods 0.000 description 2
- 238000010612 desalination reaction Methods 0.000 description 2
- 239000003814 drug Substances 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 238000003912 environmental pollution Methods 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 125000000896 monocarboxylic acid group Chemical group 0.000 description 2
- LXNHXLLTXMVWPM-UHFFFAOYSA-N pyridoxine Chemical compound CC1=NC=C(CO)C(CO)=C1O LXNHXLLTXMVWPM-UHFFFAOYSA-N 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L sodium carbonate Substances [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- XERJKGMBORTKEO-VZUCSPMQSA-N (1e)-2-(ethylcarbamoylamino)-n-methoxy-2-oxoethanimidoyl cyanide Chemical compound CCNC(=O)NC(=O)C(\C#N)=N\OC XERJKGMBORTKEO-VZUCSPMQSA-N 0.000 description 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- 239000005756 Cymoxanil Substances 0.000 description 1
- LPHGQDQBBGAPDZ-UHFFFAOYSA-N Isocaffeine Natural products CN1C(=O)N(C)C(=O)C2=C1N(C)C=N2 LPHGQDQBBGAPDZ-UHFFFAOYSA-N 0.000 description 1
- OFOBLEOULBTSOW-UHFFFAOYSA-L Malonate Chemical compound [O-]C(=O)CC([O-])=O OFOBLEOULBTSOW-UHFFFAOYSA-L 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 150000001408 amides Chemical class 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 229960001948 caffeine Drugs 0.000 description 1
- VJEONQKOZGKCAK-UHFFFAOYSA-N caffeine Natural products CN1C(=O)N(C)C(=O)C2=C1C=CN2C VJEONQKOZGKCAK-UHFFFAOYSA-N 0.000 description 1
- 238000004587 chromatography analysis Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000006837 decompression Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 239000000975 dye Substances 0.000 description 1
- ZIUSEGSNTOUIPT-UHFFFAOYSA-N ethyl 2-cyanoacetate Chemical compound CCOC(=O)CC#N ZIUSEGSNTOUIPT-UHFFFAOYSA-N 0.000 description 1
- 239000012847 fine chemical Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- 238000000655 nuclear magnetic resonance spectrum Methods 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 238000007781 pre-processing Methods 0.000 description 1
- RADKZDMFGJYCBB-UHFFFAOYSA-N pyridoxal hydrochloride Natural products CC1=NC=C(CO)C(C=O)=C1O RADKZDMFGJYCBB-UHFFFAOYSA-N 0.000 description 1
- 239000011541 reaction mixture Substances 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- FDRCDNZGSXJAFP-UHFFFAOYSA-M sodium chloroacetate Chemical compound [Na+].[O-]C(=O)CCl FDRCDNZGSXJAFP-UHFFFAOYSA-M 0.000 description 1
- MNWBNISUBARLIT-UHFFFAOYSA-N sodium cyanide Chemical compound [Na+].N#[C-] MNWBNISUBARLIT-UHFFFAOYSA-N 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
- 239000011726 vitamin B6 Substances 0.000 description 1
- 235000019158 vitamin B6 Nutrition 0.000 description 1
- 229940011671 vitamin b6 Drugs 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C253/00—Preparation of carboxylic acid nitriles
- C07C253/30—Preparation of carboxylic acid nitriles by reactions not involving the formation of cyano groups
Abstract
The invention provides a preparation method of cyanoacetic acid, which comprises the following steps: (1) Mixing a sulfhydryl-containing compound with sodium cyanoacetate, and performing pretreatment to obtain a pretreatment liquid; (2) Acidizing the pretreatment liquid obtained in the step (1) with an acidic substance to obtain cyanoacetic acid complex; and decomposing the cyanoacetic acid complex to obtain the cyanoacetic acid. The sulfhydryl in the sulfhydryl-containing compound is a nucleophilic donor, can form a covalent bond with cyano in a substrate sodium cyanoacetate, plays a role in protecting cyano, ensures that cyanoacetic acid generated by the reaction is not easy to decompose in the subsequent dehydration process, and is beneficial to improving the yield of cyanoacetic acid; meanwhile, the substance is not mutually soluble with water, and after the sodium chloride is added, the wrapping of the sodium chloride on the cyanoacetic acid can be reduced, so that the purity of the sodium chloride is improved, and the yield of the cyanoacetic acid is also improved.
Description
Technical Field
The invention belongs to the technical field of organic chemistry, and particularly relates to a preparation method of cyanoacetic acid.
Background
The cyanoacetic acid is white hygroscopic crystal at normal temperature, is an important organic synthesis raw material and medicine and dye intermediate, and can be used for preparing many fine chemicals such as cyanoacetic ester, adhesive, malonate, caffeine, cymoxanil, vitamin B6 and the like. The cyanoacetate compound has important application in medicine, agriculture, new materials and the like.
The chloroacetic acid cyanidation method is the most mature method for industrially synthesizing cyanoacetic acid at present, and is characterized in that chloroacetic acid is used as a raw material, sodium hydroxide or sodium carbonate is used for neutralization to obtain sodium chloroacetate aqueous solution, sodium cyanide is added for cyanidation to obtain sodium cyanoacetate aqueous solution, hydrochloric acid is added for acidification to obtain cyanoacetic acid aqueous solution, and finally cyanoacetic acid with different concentrations is obtained through dehydration. The reaction equation is as follows:
2ClCH 2 COOH+Na 2 CO 3 →2ClCH 2 COONa+H 2 O+CO 2
ClCH 2 COONa+NaCN→CNCH 2 COONa+NaCl
CNCH 2 COONa+HCl→CNCH 2 COOH+NaCl
patent CN102336684a discloses a preparation method of cyanoacetic acid, which uses hydrogen chloride gas to replace hydrochloric acid to neutralize sodium cyanoacetate solution, thereby reducing the addition of water and improving the content of cyanoacetic acid, greatly reducing steam consumption, and further reducing production cost.
Patent CN105294491a discloses a method for preparing cyanoacetic acid by continuous dehydration, after neutralizing, cyaniding and acidifying chloroacetic acid to obtain aqueous solution of cyanoacetic acid, adopting coupling of multiple effect evaporation and forced circulation evaporation to continuously dehydrate, removing continuously precipitated sodium chloride in the dehydration process to prepare cyanoacetic acid, and using multiple effect evaporation to prepare cyanoacetic acid, so that not only the steam consumption is reduced, but also each effect is carried out, sodium chloride is filtered, thus, the precipitated sodium chloride can be timely filtered and removed, the solid-to-liquid ratio is reduced, the selection of filtering equipment is facilitated, the operation is simple, the equipment utilization rate is high, the steam consumption is low, and the cyanoacetic acid yield is high due to short dehydration time, the cyanoacetic acid yield is high, and the cyanoacetic acid yield is about 70%, and is greater than 98%.
Patent CN105294491a discloses a preparation method of environment-friendly clean cyanoacetic acid and its derivatives, by evaporating and concentrating part of water into a mixture containing cyanoacetic acid and sodium chloride, filtering to remove part of precipitated sodium chloride solids, avoiding the disadvantages of large amount of decomposition and low yield of cyanoacetic acid caused by traditional distillation concentration and desalination, and separating the solution containing cyanoacetic acid and sodium chloride into cyanoacetic acid solution and sodium chloride solution by continuous chromatography after desalination, avoiding decomposition in the cyanoacetic acid concentration process, and obtaining cyanoacetic acid solution with low chloride ion content or high-content solid cyanoacetic acid product and its derivatives.
Patent CN105481717a discloses a preparation method of cyanoacetic acid and its derivatives, wherein the cyanidation reaction and the acidification reaction are both intermittent reactions, but the acidified mixed solution is separated by adopting a continuous chromatographic separation system filled with ammonium chromatographic separation resin to obtain cyanoacetic acid solution and sodium chloride solution, but the cyanidation reaction and the acidification reaction are both intermittent reactions, the operation steps are complex, a large amount of heat generated by the cyanidation reaction cannot be removed in time in a reaction kettle, the cyano group is hydrolyzed, the color of the obtained product is deepened, and the yield is reduced. In addition, the product and the raw materials are back mixed, so that the local alkalinity of the reaction liquid is increased, cyano is hydrolyzed into amide or acid under alkaline conditions, the product yield is further reduced, and the side reaction is increased.
In summary, in the synthesis process of cyanoacetic acid, a large amount of sodium chloride is produced, organic matters such as cyanoacetic acid and chloroacetic acid are easily wrapped in the sodium chloride, and if cyanoacetic acid with higher purity is obtained, complex post-treatment is required, so that the overall production cost is increased, and the yield of cyanoacetic acid is low. In addition, the cyanoacetic acid mixed solution needs to consume a large amount of steam for long-time high-temperature dehydration, and is precipitated in a large amount due to sodium chloride in the later evaporation stage, so that the cyanoacetic acid is extremely easy to decompose due to poor heat transfer, and the product selectivity is poor and the yield is reduced. The cyanoacetic acid is easy to decompose, the selectivity of the product is poor, and the yield is reduced. The cyanoacetic acid product has high water content and high salt content, which limits the application of cyanoacetic acid. Therefore, the improvement of the cyanoacetic acid yield and content, the improvement of the purity of the byproduct sodium chloride and the simplification of the post-treatment process are important points and difficulties in the synthesis of cyanoacetic acid.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide a preparation method of cyanoacetic acid, which is characterized in that a sulfhydryl-containing compound is used for preprocessing a sodium cyanoacetate solution through the selection of raw materials and the optimization of the method, so that the problems of low cyanoacetic acid yield, high energy consumption, decomposition of cyanoacetic acid and the like in the production process of cyanoacetic acid are solved, and meanwhile, high-purity sodium chloride can be produced as a byproduct, and can be directly used as industrial salt, thereby saving the post-treatment cost and reducing the environmental pollution.
To achieve the purpose, the invention adopts the following technical scheme:
the invention provides a preparation method of cyanoacetic acid, which comprises the following steps:
(1) Mixing a sulfhydryl-containing compound with sodium cyanoacetate, and performing pretreatment to obtain a pretreatment liquid;
(2) Acidizing the pretreatment liquid obtained in the step (1) with an acidic substance to obtain cyanoacetic acid complex; and decomposing the cyanoacetic acid complex to obtain the cyanoacetic acid.
The molar ratio of the sulfhydryl-containing compound to the sodium cyanoacetate in the step (1) is (1-5): 1, for example 1:1. 2: 1. 3: 1. 4: 1. 5:1, and specific point values between the above point values, are limited in space and for the sake of brevity, the present invention is not intended to exhaustively list the specific point values encompassed by the described range.
The mercapto-containing compound of step (1) includes a mercapto-containing nitrogen heterocyclic compound.
The sulfhydryl-containing nitrogen heterocyclic compound comprises any one or a combination of at least two of 2-sulfhydryl benzothiazole, 2-sulfhydryl pyridine, 2-sulfhydryl benzimidazole, 2-sulfhydryl benzoxazole, 2-sulfhydryl-5-methyl-benzimidazole or 5-amino-2-sulfhydryl benzimidazole.
The pretreatment in step (1) may be performed for a period of time ranging from 1 to 6 h, and may be, for example, from 1 h, 2 h, 3 h, h, 5 h, 6 h, and specific point values therebetween, although the specific point values included in the range are not intended to be exhaustive for brevity and conciseness.
The pretreatment in step (1) may be carried out at a temperature of 20-60 ℃, for example, 20 ℃, 30 ℃,40 ℃,50 ℃,60 ℃, and specific values between the above values, and the present invention is not intended to be exhaustive of the specific values included in the range, for reasons of space and for reasons of simplicity.
The pretreatment in step (1) is carried out in the presence of a solvent.
The solvent comprises water.
The acidic substance in the step (2) comprises any one or a combination of at least two of hydrochloric acid, sulfuric acid, phosphoric acid and hydrogen chloride.
The molar ratio of the sodium cyanoacetate to the acidic substance is 1: (0.5-2), for example, can be 1:0.5, 1:0.8, 1:1. 1:1.2, 1:1.4, 1:1.6, 1:1.8, 1:2, and specific point values between the above point values, are limited in space and for the sake of brevity, the present invention is not intended to exhaustively list the specific point values encompassed by the described range.
The acidification reaction time is 2-5 h, and may be, for example, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h, and specific point values between the above point values, and is limited in space and for brevity, the present invention is not exhaustive of the specific point values included in the range.
The acidification reaction temperature is 40-60 ℃, for example, 40 ℃, 42 ℃, 44 ℃, 46 ℃, 48 ℃,50 ℃, 52 ℃, 54 ℃, 56 ℃, 58 ℃,60 ℃ and specific point values between the above point values, are limited in space and for the sake of brevity, and the present invention is not exhaustive of the specific point values included in the range.
The decomposition temperature is 120-140 c, for example 120 c, 125 c, 130 c, 140 c, and specific values between the above values, which are not exhaustive and are included in the scope of the present invention for the sake of brevity.
The decomposition time is 3-4.5 h, and may be, for example, 3 h, 3.5 h, 4 h, 4.5 h, and specific point values between the above point values, limited in space and for brevity, the present invention is not exhaustive of the specific point values included in the range.
And (3) after the decomposition in the step (2), further comprising post-treatment.
The post-treatment comprises liquid separation, dehydration and drying.
The post-treatment steps are conventional post-treatment steps such as standing liquid separation, decompression dehydration, solid drying and the like.
The preparation method specifically comprises the following steps:
(1) Mixing a sulfhydryl-containing compound with a sodium cyanoacetate solution, and performing pretreatment to obtain a pretreatment solution;
the molar ratio of the sulfhydryl-containing compound to sodium cyanoacetate is (1-5): 1, a step of; the sulfhydryl-containing compound comprises any one or at least two of 2-sulfhydryl benzothiazole, 2-sulfhydryl pyridine, 2-sulfhydryl benzimidazole, 2-sulfhydryl benzoxazole, 2-sulfhydryl-5-methyl-benzimidazole or 5-amino-2-sulfhydryl benzimidazole; the pretreatment time is 1-6 h; the temperature of the pretreatment is 20-60 ℃;
(2) Acidizing the pretreatment liquid obtained in the step (1) with an acidic substance to obtain a reaction liquid containing cyanoacetic acid complex; treating the reaction solution at 120-140 ℃ for 3-4.5. 4.5 h, and separating, dehydrating and drying to obtain the cyanoacetic acid;
the molar ratio of the sodium cyanoacetate to the acidic substance is 1: (0.5-2); the acidification reaction time is 2-4.5 h; the temperature of the acidification reaction is 40-60 ℃; the acidic substance comprises any one or a combination of at least two of hydrochloric acid, sulfuric acid, phosphoric acid or hydrogen chloride.
Compared with the prior art, the invention has the following beneficial effects:
the invention provides a preparation method of cyanoacetic acid, wherein mercapto in mercapto compound is nucleophilic donor, which can form covalent bond with cyano in substrate sodium cyanoacetate to protect cyano, so that cyanoacetic acid generated by reaction is not easy to decompose in subsequent dehydration process, thus being beneficial to improving yield of cyanoacetic acid; meanwhile, the substance is not mutually soluble with water, and after the sodium chloride is added, the wrapping of the sodium chloride on the cyanoacetic acid can be reduced, so that the purity of the sodium chloride is improved, the yield of the cyanoacetic acid is improved, the yield is 92.3-99.4%, the content is 97.2-98%, and the post-treatment operation is simplified; the reaction of the formed covalent bond belongs to reversible reaction, and cyanoacetic acid and a sulfhydryl-containing compound can be obtained by heating and decomposed, and the sulfhydryl-containing compound can be used continuously; pretreating the sodium cyanoacetate reaction liquid after the cyanidation reaction, improving the content of cyanoacetic acid in the product, improving the purity of byproduct sodium chloride, reducing the wrapping of sodium chloride on cyanoacetic acid, reducing the decomposition of cyanoacetic acid and improving the yield of cyanoacetic acid; the problems of energy consumption and environmental pollution in the synthesis process of cyanoacetic acid can be reduced, and the byproduct sodium chloride with high purity is obtained, wherein the content of the obtained sodium chloride is 96-98%; simplifies the post-treatment process, reduces the comprehensive economic cost of cyanoacetic acid production, and has good industrial application prospect.
Drawings
FIG. 1 is an NMR spectrum of cyanoacetic acid obtained in example 1;
FIG. 2 is an NMR chart of cyanoacetic acid obtained in comparative example 1.
Detailed Description
The technical scheme of the invention is further described by the following specific embodiments. It will be apparent to those skilled in the art that the examples are merely to aid in understanding the invention and are not to be construed as a specific limitation thereof.
Product nuclear magnetic analysis conditions:
instrument type: bruker Avance III HD 400M;
probe: PA BBO 400S1 BBF-H-D-05Z SP.
The experimental materials used in the examples and comparative examples of the present invention are as follows:
example 1
The embodiment provides a preparation method of cyanoacetic acid, which comprises the following steps:
adding 56.34g (0.5 mol) of sodium cyanoacetate into a three-neck flask at room temperature, adding 30.0g of purified water for dissolution, starting stirring, adding 117g (0.7 mol) of 2-mercaptobenzothiazole after complete dissolution, continuously stirring for 4.0 hours at the pretreatment temperature of 40 ℃, adding 49.3g of 37wt% hydrochloric acid solution (0.5 mol) into the reaction solution for acidification reaction, and carrying out acidification reaction at 40 ℃ for 2 hours to obtain a cyanoacetic acid complex and sodium chloride mixed solution; standing for separating to obtain cyanoacetic acid complex and chlorineSodium salt aqueous solution. Adding a proper amount of purified water into cyanoacetic acid complex, preferably uniformly dispersing, heating to a decomposition temperature of 130 ℃, completely decomposing the complex for 3 hours, standing for separating liquid, collecting cyanoacetic acid aqueous solution, decompressing and dehydrating, drying by anhydrous magnesium sulfate to obtain 42.62g of solid cyanoacetic acid, wherein the yield is 98.2%, the content is 98.0%, and the nuclear magnetic carbon spectrum obtained by Bruker Avance III HD 400M nuclear magnetic test is shown in figure 1, 13 C NMR (600MHz, D 2 O) δ 167.72, 115.58, 24.52。
the aqueous solution of sodium chloride was dehydrated under reduced pressure and dried over anhydrous magnesium sulfate to give 29.82g of sodium chloride as a solid with a content of 98.0%.
Examples 2 to 9
The sodium cyanide reaction solution was pretreated with 2-mercaptobenzothiazole, and the molar ratio of the sodium cyanide reaction solution to the sodium cyanide reaction solution, the heating temperature, the pretreatment time, the acidification time, the temperature, the decomposition time and other parameters were changed, and the reaction results under other operating conditions are shown in Table 1.
TABLE 1
Example 10
The embodiment provides a preparation method of cyanoacetic acid, which comprises the following steps:
adding 56.34g (0.5 mol) of sodium cyanoacetate into a three-neck flask at room temperature, adding 30.0g of purified water for dissolution, starting stirring, adding 111.17g (1.0 mol) of 2-mercaptopyridine after complete dissolution, heating to 50 ℃, continuously stirring for 4.0 hours, adding 49.3g of 37wt% hydrochloric acid solution (0.5 mol) into the reaction solution for acidification reaction, and carrying out acidification reaction at 50 ℃ for 2.5 hours to obtain a cyanoacetic acid complex and sodium chloride mixed solution; standing for separating to obtain cyanoacetic acid complex and sodium chloride water solution. Adding a proper amount of purified water into the cyanoacetic acid complex, preferably uniformly dispersing, heating to a decomposition temperature of 120 ℃, standing for separating liquid after the complex is completely decomposed, collecting cyanoacetic acid aqueous solution, decompressing and dehydrating, and drying by anhydrous magnesium sulfate to obtain 40.26g of solid cyanoacetic acid, wherein the yield is 92.3%, and the content is 97.5%.
The aqueous solution of sodium chloride was dehydrated under reduced pressure and dried over anhydrous magnesium sulfate to give 30.44g of sodium chloride as a solid with a content of 96.0%.
Example 11
The embodiment provides a preparation method of cyanoacetic acid, which comprises the following steps:
adding 56.34g (0.5 mol) of sodium cyanoacetate into a three-neck flask at room temperature, adding 30.0g of purified water for dissolution, starting stirring, adding 75.1g (0.5 mol) of 2-mercaptobenzimidazole after complete dissolution, heating to 50 ℃, continuously stirring for 5.0 hours, adding 49.3g of 37wt% hydrochloric acid solution (0.5 mol) into the reaction solution for acidification reaction, and obtaining cyanoacetic acid complex and sodium chloride mixed solution after acidification reaction for 3 hours at 50 ℃; standing for separating to obtain cyanoacetic acid complex and sodium chloride water solution. Adding a proper amount of purified water into the cyanoacetic acid complex, preferably uniformly dispersing, heating to a decomposition temperature of 130 ℃, completely decomposing the complex for 3.5 hours, standing for separating liquid, collecting cyanoacetic acid aqueous solution, decompressing and dehydrating, and drying by anhydrous magnesium sulfate to obtain 43.14g of solid cyanoacetic acid, wherein the yield is 99.4%, and the content is 98.0%.
The aqueous solution of sodium chloride was dehydrated under reduced pressure and dried over anhydrous magnesium sulfate to give 29.82g of sodium chloride as a solid with a content of 98.0%.
Example 12
The embodiment provides a preparation method of cyanoacetic acid, which comprises the following steps:
adding 56.34g (0.5 mol) of sodium cyanoacetate into a three-neck flask at room temperature, adding 30.0g of purified water for dissolution, starting stirring, adding 226.78g (1.5 mol) of 2-mercaptobenzoxazole after complete dissolution, heating to 40 ℃, continuously stirring for 5.0 hours, adding 49.3g of 37wt% hydrochloric acid solution (0.5 mol) into the reaction solution for acidification reaction, and carrying out acidification reaction at 50 ℃ for 3 hours to obtain a cyanoacetic acid complex and sodium chloride mixed solution; standing for separating to obtain cyanoacetic acid complex and sodium chloride water solution. Adding a proper amount of purified water into the cyanoacetic acid complex, preferably uniformly dispersing, heating to a decomposition temperature of 130 ℃, standing for 3.5 hours until the complex is completely decomposed, separating liquid, collecting cyanoacetic acid aqueous solution, decompressing and dehydrating, and drying by anhydrous magnesium sulfate to obtain 41.18g of solid cyanoacetic acid, wherein the yield is 94.5%, and the content is 97.6%.
The aqueous solution of sodium chloride was dehydrated under reduced pressure and dried over anhydrous magnesium sulfate to give 30.06g of sodium chloride as a solid with a content of 97.2%.
Example 13
The embodiment provides a preparation method of cyanoacetic acid, which comprises the following steps:
adding 56.34g (0.5 mol) of sodium cyanoacetate into a three-neck flask at room temperature, adding 30.0g of purified water for dissolution, starting stirring, adding 167.25g (1.0 mol) of 2-mercapto-5-methyl-benzimidazole after complete dissolution, heating to 30 ℃, continuously stirring for 6.0 hours, adding 49.3g of 37wt% hydrochloric acid solution (0.5 mol) into the reaction solution for acidification reaction, and carrying out acidification reaction at 40 ℃ for 4 hours to obtain a cyanoacetic acid complex and sodium chloride mixed solution; standing for separating to obtain cyanoacetic acid complex and sodium chloride water solution. Adding a proper amount of purified water into the cyanoacetic acid complex, preferably uniformly dispersing, heating to a decomposition temperature of 140 ℃, standing for 3.8 hours until the complex is completely decomposed, separating liquid, collecting cyanoacetic acid aqueous solution, decompressing and dehydrating, and drying by anhydrous magnesium sulfate to obtain 42.40g of solid cyanoacetic acid, wherein the yield is 97.7%, and the content is 98.0%.
The aqueous solution of sodium chloride was dehydrated under reduced pressure and dried over anhydrous magnesium sulfate to give 29.8g of sodium chloride as a solid with a content of 98.0%.
Example 14
The embodiment provides a preparation method of cyanoacetic acid, which comprises the following steps:
adding 56.34g (0.5 mol) of sodium cyanoacetate into a three-neck flask at room temperature, adding 30.0g of purified water for dissolution, starting stirring, adding 330.44g (2.0 mol) of 5-amino-2-mercaptobenzimidazole after complete dissolution, heating to 60 ℃, continuously stirring for 5.0 hours, adding 49.3g of 37wt% hydrochloric acid solution (0.5 mol) into the reaction solution for acidification reaction, and obtaining cyanoacetic acid complex and sodium chloride mixed solution after acidification reaction for 3 hours at 60 ℃; standing for separating to obtain cyanoacetic acid complex and sodium chloride water solution. Adding a proper amount of purified water into the cyanoacetic acid complex, preferably uniformly dispersing, heating to a decomposition temperature of 140 ℃, standing for 4.5 hours until the complex is completely decomposed, separating liquid, collecting cyanoacetic acid aqueous solution, decompressing and dehydrating, and drying by anhydrous magnesium sulfate to obtain 42.18g of solid cyanoacetic acid, wherein the yield is 97.2%, and the content is 98.0%.
The aqueous solution of sodium chloride was dehydrated under reduced pressure and dried over anhydrous magnesium sulfate to give 29.82g of sodium chloride as a solid with a content of 98.0%.
Example 15
The embodiment provides a preparation method of cyanoacetic acid, which comprises the following steps:
the sodium cyanoacetate was pretreated by using the 2-mercaptobenzothiazole recovered in example 1.
Adding 56.34g (0.5 mol) of sodium cyanoacetate into a three-neck flask at room temperature, adding 30.0g of purified water for dissolution, starting stirring, adding 115.4g (0.69 mol) of 2-mercaptobenzothiazole after complete dissolution, heating to 40 ℃, continuously stirring for 4.0 hours, adding 49.3g of 37wt% hydrochloric acid solution (0.5 mol) into the reaction solution for acidification reaction, and obtaining cyanoacetic acid complex and sodium chloride mixed solution after acidification reaction for 3 hours at 50 ℃; standing for separating to obtain cyanoacetic acid complex and sodium chloride water solution. Adding a proper amount of purified water into the cyanoacetic acid complex, preferably uniformly dispersing, heating to a decomposition temperature of 120 ℃, standing for 3.5 hours until the complex is completely decomposed, separating liquid, collecting cyanoacetic acid aqueous solution, decompressing and dehydrating, and drying by anhydrous magnesium sulfate to obtain 42.62g of solid cyanoacetic acid, wherein the yield is 98.2%, and the content is 98.0%.
The aqueous solution of sodium chloride was dehydrated under reduced pressure and dried over anhydrous magnesium sulfate to give 29.82g of sodium chloride as a solid with a content of 98.0%.
Example 16
The embodiment provides a preparation method of cyanoacetic acid, which comprises the following steps:
adding 56.34g (0.5 mol) of sodium cyanoacetate into a three-neck flask at room temperature, adding 30.0g of purified water for dissolution, starting stirring, adding 83.57g (0.5 mol) of 2-mercaptobenzothiazole after complete dissolution, heating to 40 ℃, continuously stirring for 4.0 hours, adding 57.65g of 85wt% phosphoric acid solution (0.5 mol) into the reaction solution for acidification reaction, and carrying out acidification reaction at 60 ℃ for 3 hours to obtain a cyanoacetic acid complex and sodium phosphate mixed solution; standing and separating to obtain cyanoacetic acid complex and sodium phosphate water solution. Adding a proper amount of purified water into the cyanoacetic acid complex, preferably uniformly dispersing, heating to a decomposition temperature of 120 ℃, standing for 4.0 hours until the complex is completely decomposed, separating liquid, collecting cyanoacetic acid aqueous solution, decompressing and dehydrating, and drying by anhydrous magnesium sulfate to obtain 42.53g of solid cyanoacetic acid, wherein the yield is 98.0%, and the content is 98.0%.
After dehydration under reduced pressure of the aqueous solution of sodium phosphate, the aqueous solution was dried over anhydrous magnesium sulfate to obtain 83.73g of sodium phosphate solid with a content of 98.0%.
Example 17
The embodiment provides a preparation method of cyanoacetic acid, which comprises the following steps:
adding 56.34g (0.5 mol) of sodium cyanoacetate into a three-neck flask at room temperature, adding 30.0g of purified water for dissolution, starting stirring, adding 83.57g (0.5 mol) of 2-mercaptobenzothiazole after complete dissolution, heating to 40 ℃, continuously stirring for 4.0 hours, introducing 20.0g of dry hydrogen chloride gas into the reaction solution for acidification reaction, and obtaining a cyanoacetic acid complex and sodium chloride mixed solution after acidification reaction for 4 hours at 60 ℃; standing for separating to obtain cyanoacetic acid complex and sodium chloride water solution. Adding a proper amount of purified water into the cyanoacetic acid complex, preferably uniformly dispersing, heating to the decomposition temperature of 120 ℃, completely decomposing the complex for 4.0 hours, standing for separating liquid, collecting cyanoacetic acid aqueous solution, decompressing and dehydrating, and drying by anhydrous magnesium sulfate to obtain 42.14g of solid cyanoacetic acid, wherein the yield is 97.1%, and the content is 98.0%.
The aqueous solution of sodium chloride was dehydrated under reduced pressure and dried over anhydrous magnesium sulfate to give 30.28g of sodium phosphate as a solid with a content of 96.5%.
Comparative example 1
This comparative example provides a process for the preparation of cyanoacetic acid, comprising:
at room temperature, 56.34g (0.5 mol) of sodium cyanoacetate was added to a three-necked flask, 30.0g of purified water was added thereto for dissolution, stirring was started, after complete dissolution, the temperature was raised to 40℃and 49.3g of 37wt% hydrochloric acid solution (0.5 mol) was added to the reaction mixture for acidification reaction, and acidification was carried out at 50℃for 5 hours. The reaction solution was dehydrated under reduced pressure and dried over anhydrous magnesium sulfate to give 24.53g of solid cyanoacetic acid, yield 45.6% and content 78.1%. The nuclear magnetic carbon spectrum obtained by using Bruker Avance III HD 400M nuclear magnetic test is shown in figure 2, 13 C NMR (600MHz, D 2 O) δ 162.24, 56.80, 27.58。
examples 1-17, the cyanoacetic acid yield obtained by the preparation method provided by the patent is 92.3-99.4%, the content is 97.2-98%, and the cyanoacetic acid yield is significantly higher than that obtained by the preparation method provided by comparative example 1; meanwhile, the weight of the obtained sodium chloride is 29.8-30.4g, and the content is 96-98%.
The applicant states that the present invention is illustrated by the above examples as a method for preparing cyanoacetic acid of the present invention, but the present invention is not limited to the above examples, i.e. it is not meant that the present invention must be practiced by relying on the above examples. It should be apparent to those skilled in the art that any modification of the present invention, equivalent substitution of raw materials for the product of the present invention, addition of auxiliary components, selection of specific modes, etc., falls within the scope of the present invention and the scope of disclosure.
Claims (7)
1. A process for the preparation of cyanoacetic acid, comprising the steps of:
(1) Mixing the sulfhydryl-containing nitrogen heterocyclic compound with sodium cyanoacetate, and performing pretreatment to obtain a pretreatment liquid;
the sulfhydryl-containing nitrogen heterocyclic compound is any one of 2-sulfhydryl benzothiazole, 2-sulfhydryl pyridine, 2-sulfhydryl benzimidazole, 2-sulfhydryl benzoxazole, 2-sulfhydryl-5-methyl-benzimidazole or 5-amino-2-sulfhydryl benzimidazole, the pretreatment time is 1-6 h, the pretreatment temperature is 20-60 ℃, the pretreatment is carried out in the presence of a solvent, and the solvent is water;
(2) Acidifying the pretreatment liquid obtained in the step (1) with an acidic substance to obtain a cyanoacetic acid complex, and decomposing the cyanoacetic acid complex to obtain cyanoacetic acid;
the decomposition temperature is 120-140 ℃, and the decomposition time is 3-4.5 h.
2. The method according to claim 1, wherein the molar ratio of the mercapto-containing nitrogen heterocyclic compound to sodium cyanoacetate in step (1) is (1-5): 1.
3. the method according to claim 1, wherein the acidic substance in the step (2) comprises any one or a combination of at least two of hydrochloric acid, sulfuric acid, phosphoric acid and hydrogen chloride.
4. The method according to claim 1, wherein the molar ratio of sodium cyanoacetate to acidic substance is 1: (0.5-2), wherein the time of the acidification reaction is 2-5 h, and the temperature of the acidification reaction is 40-60 ℃.
5. The method of claim 1, wherein the decomposing in step (2) further comprises post-treatment.
6. The method according to claim 5, wherein the post-treatment comprises liquid separation, dehydration and drying.
7. The preparation method according to any one of claims 1 to 6, characterized in that it comprises in particular the following steps:
(1) Mixing the sulfhydryl-containing nitrogen heterocyclic compound with sodium cyanoacetate solution, and performing pretreatment to obtain pretreatment liquid;
the mol ratio of the sulfhydryl-containing nitrogen heterocyclic compound to sodium cyanoacetate is (1-5): 1, a step of; the sulfhydryl-containing nitrogen heterocyclic compound is any one of 2-sulfhydryl benzothiazole, 2-sulfhydryl pyridine, 2-sulfhydryl benzimidazole, 2-sulfhydryl benzoxazole, 2-sulfhydryl-5-methyl-benzimidazole or 5-amino-2-sulfhydryl benzimidazole; the pretreatment time is 1-6 h; the temperature of the pretreatment is 20-60 ℃;
(2) Acidizing the pretreatment liquid obtained in the step (1) with an acidic substance to obtain a reaction liquid containing cyanoacetic acid complex; treating the reaction solution at 120-140 ℃ for 3-4.5. 4.5 h, and separating, dehydrating and drying to obtain the cyanoacetic acid;
the molar ratio of the sodium cyanoacetate to the acidic substance is 1: (0.5-2); the acidification reaction time is 2-4.5 h; the temperature of the acidification reaction is 40-60 ℃; the acidic substance comprises any one or a combination of at least two of hydrochloric acid, sulfuric acid, phosphoric acid or hydrogen chloride.
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| CN106496068A (en) * | 2016-08-31 | 2017-03-15 | 内蒙古紫光化工有限责任公司 | The preparation method of dimethyl malenate |
| CN111393323A (en) * | 2020-04-08 | 2020-07-10 | 高春燕 | Environment-friendly clean production method of high-purity cyanoacetic acid, cyanoacetic ester and malonic ester |
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| CN103360281A (en) * | 2012-03-26 | 2013-10-23 | 柯尼卡美能达商用科技株式会社 | Method for producing cyanoacetic acid, method for producing cyanoacetic acid derivative and method for producing metal containing compound |
| CN103724191A (en) * | 2014-01-28 | 2014-04-16 | 重庆紫光化工股份有限公司 | Dimethyl malonate preparation method |
| CN105481717A (en) * | 2015-11-20 | 2016-04-13 | 重庆紫光化工股份有限公司 | Preparation method for cyanoacetic acid and derivatives thereof |
| CN106045879A (en) * | 2016-08-15 | 2016-10-26 | 国药集团化学试剂有限公司 | Preparation method for cyanoacetic acid |
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