CN115181016B - Synthesis method of dibenzoylmethane - Google Patents
Synthesis method of dibenzoylmethane Download PDFInfo
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- CN115181016B CN115181016B CN202210583490.7A CN202210583490A CN115181016B CN 115181016 B CN115181016 B CN 115181016B CN 202210583490 A CN202210583490 A CN 202210583490A CN 115181016 B CN115181016 B CN 115181016B
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- enamine
- benzoyl chloride
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- NZZIMKJIVMHWJC-UHFFFAOYSA-N dibenzoylmethane Chemical compound C=1C=CC=CC=1C(=O)CC(=O)C1=CC=CC=C1 NZZIMKJIVMHWJC-UHFFFAOYSA-N 0.000 title claims abstract description 39
- 238000001308 synthesis method Methods 0.000 title claims description 7
- 238000006243 chemical reaction Methods 0.000 claims abstract description 78
- RWRDLPDLKQPQOW-UHFFFAOYSA-N Pyrrolidine Chemical compound C1CCNC1 RWRDLPDLKQPQOW-UHFFFAOYSA-N 0.000 claims abstract description 63
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims abstract description 59
- FYSNRJHAOHDILO-UHFFFAOYSA-N thionyl chloride Chemical compound ClS(Cl)=O FYSNRJHAOHDILO-UHFFFAOYSA-N 0.000 claims abstract description 45
- KWOLFJPFCHCOCG-UHFFFAOYSA-N Acetophenone Chemical compound CC(=O)C1=CC=CC=C1 KWOLFJPFCHCOCG-UHFFFAOYSA-N 0.000 claims abstract description 40
- WPYMKLBDIGXBTP-UHFFFAOYSA-N benzoic acid Chemical compound OC(=O)C1=CC=CC=C1 WPYMKLBDIGXBTP-UHFFFAOYSA-N 0.000 claims abstract description 33
- 150000002081 enamines Chemical class 0.000 claims abstract description 31
- PASDCCFISLVPSO-UHFFFAOYSA-N benzoyl chloride Chemical compound ClC(=O)C1=CC=CC=C1 PASDCCFISLVPSO-UHFFFAOYSA-N 0.000 claims abstract description 27
- 238000000034 method Methods 0.000 claims abstract description 21
- 239000005711 Benzoic acid Substances 0.000 claims abstract description 16
- 235000010233 benzoic acid Nutrition 0.000 claims abstract description 16
- 238000002360 preparation method Methods 0.000 claims abstract description 12
- 238000006555 catalytic reaction Methods 0.000 claims abstract description 7
- JOXIMZWYDAKGHI-UHFFFAOYSA-N toluene-4-sulfonic acid Chemical compound CC1=CC=C(S(O)(=O)=O)C=C1 JOXIMZWYDAKGHI-UHFFFAOYSA-N 0.000 claims abstract description 6
- 238000005903 acid hydrolysis reaction Methods 0.000 claims abstract description 4
- 238000003379 elimination reaction Methods 0.000 claims abstract description 4
- 230000000269 nucleophilic effect Effects 0.000 claims abstract description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 22
- 230000035484 reaction time Effects 0.000 claims description 12
- 238000010992 reflux Methods 0.000 claims description 9
- 238000005406 washing Methods 0.000 claims description 7
- 238000004821 distillation Methods 0.000 claims description 6
- 238000001816 cooling Methods 0.000 claims description 4
- 238000005292 vacuum distillation Methods 0.000 claims description 4
- 230000002194 synthesizing effect Effects 0.000 claims 6
- 239000002351 wastewater Substances 0.000 abstract description 10
- 239000002904 solvent Substances 0.000 abstract description 9
- 239000002253 acid Substances 0.000 abstract description 4
- 238000007086 side reaction Methods 0.000 abstract description 4
- 238000010189 synthetic method Methods 0.000 abstract description 4
- 238000004065 wastewater treatment Methods 0.000 abstract description 3
- 238000012545 processing Methods 0.000 abstract description 2
- 150000003839 salts Chemical class 0.000 abstract description 2
- 239000000047 product Substances 0.000 description 32
- 230000000052 comparative effect Effects 0.000 description 23
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 18
- NQRYJNQNLNOLGT-UHFFFAOYSA-N Piperidine Chemical compound C1CCNCC1 NQRYJNQNLNOLGT-UHFFFAOYSA-N 0.000 description 13
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 12
- YNAVUWVOSKDBBP-UHFFFAOYSA-N Morpholine Chemical compound C1COCCN1 YNAVUWVOSKDBBP-UHFFFAOYSA-N 0.000 description 10
- 239000002994 raw material Substances 0.000 description 10
- 230000008569 process Effects 0.000 description 9
- 239000007788 liquid Substances 0.000 description 8
- 230000004048 modification Effects 0.000 description 8
- 238000012986 modification Methods 0.000 description 8
- 238000002474 experimental method Methods 0.000 description 6
- 238000012827 research and development Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 150000003335 secondary amines Chemical class 0.000 description 5
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 4
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 4
- 238000001704 evaporation Methods 0.000 description 4
- 230000008020 evaporation Effects 0.000 description 4
- BDAGIHXWWSANSR-UHFFFAOYSA-N methanoic acid Natural products OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 description 4
- QPJVMBTYPHYUOC-UHFFFAOYSA-N methyl benzoate Chemical compound COC(=O)C1=CC=CC=C1 QPJVMBTYPHYUOC-UHFFFAOYSA-N 0.000 description 4
- 238000004064 recycling Methods 0.000 description 4
- 239000008399 tap water Substances 0.000 description 4
- 235000020679 tap water Nutrition 0.000 description 4
- -1 DBM sodium salt Chemical class 0.000 description 3
- 239000003054 catalyst Substances 0.000 description 3
- 239000012467 final product Substances 0.000 description 3
- 239000001257 hydrogen Substances 0.000 description 3
- 229910052739 hydrogen Inorganic materials 0.000 description 3
- 230000002035 prolonged effect Effects 0.000 description 3
- 239000002699 waste material Substances 0.000 description 3
- YFKBXYGUSOXJGS-UHFFFAOYSA-N 1,3-Diphenyl-2-propanone Chemical compound C=1C=CC=CC=1CC(=O)CC1=CC=CC=C1 YFKBXYGUSOXJGS-UHFFFAOYSA-N 0.000 description 2
- OSWFIVFLDKOXQC-UHFFFAOYSA-N 4-(3-methoxyphenyl)aniline Chemical compound COC1=CC=CC(C=2C=CC(N)=CC=2)=C1 OSWFIVFLDKOXQC-UHFFFAOYSA-N 0.000 description 2
- KXDAEFPNCMNJSK-UHFFFAOYSA-N Benzamide Chemical compound NC(=O)C1=CC=CC=C1 KXDAEFPNCMNJSK-UHFFFAOYSA-N 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- NQTADLQHYWFPDB-UHFFFAOYSA-N N-Hydroxysuccinimide Chemical compound ON1C(=O)CCC1=O NQTADLQHYWFPDB-UHFFFAOYSA-N 0.000 description 2
- KEAYESYHFKHZAL-UHFFFAOYSA-N Sodium Chemical compound [Na] KEAYESYHFKHZAL-UHFFFAOYSA-N 0.000 description 2
- WQDUMFSSJAZKTM-UHFFFAOYSA-N Sodium methoxide Chemical compound [Na+].[O-]C WQDUMFSSJAZKTM-UHFFFAOYSA-N 0.000 description 2
- 239000008346 aqueous phase Substances 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 235000019253 formic acid Nutrition 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 239000010410 layer Substances 0.000 description 2
- 239000004611 light stabiliser Substances 0.000 description 2
- 238000004811 liquid chromatography Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229940095102 methyl benzoate Drugs 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000012044 organic layer Substances 0.000 description 2
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 2
- 238000004321 preservation Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 229910000029 sodium carbonate Inorganic materials 0.000 description 2
- 239000012312 sodium hydride Substances 0.000 description 2
- 229910000104 sodium hydride Inorganic materials 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- IOGXOCVLYRDXLW-UHFFFAOYSA-N tert-butyl nitrite Chemical compound CC(C)(C)ON=O IOGXOCVLYRDXLW-UHFFFAOYSA-N 0.000 description 2
- 239000012414 tert-butyl nitrite Substances 0.000 description 2
- VSWICNJIUPRZIK-UHFFFAOYSA-N 2-piperideine Chemical compound C1CNC=CC1 VSWICNJIUPRZIK-UHFFFAOYSA-N 0.000 description 1
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 1
- 229920000122 acrylonitrile butadiene styrene Polymers 0.000 description 1
- 150000001263 acyl chlorides Chemical class 0.000 description 1
- 230000010933 acylation Effects 0.000 description 1
- 238000005917 acylation reaction Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- KCXMKQUNVWSEMD-UHFFFAOYSA-N benzyl chloride Chemical compound ClCC1=CC=CC=C1 KCXMKQUNVWSEMD-UHFFFAOYSA-N 0.000 description 1
- 229940073608 benzyl chloride Drugs 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 238000012512 characterization method Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 150000001805 chlorine compounds Chemical class 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 230000021615 conjugation Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 125000005594 diketone group Chemical group 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000005886 esterification reaction Methods 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 231100000956 nontoxicity Toxicity 0.000 description 1
- 239000012434 nucleophilic reagent Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000001953 recrystallisation Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 229910052938 sodium sulfate Inorganic materials 0.000 description 1
- 235000011152 sodium sulphate Nutrition 0.000 description 1
- 229920001169 thermoplastic Polymers 0.000 description 1
- 239000004416 thermosoftening plastic Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
- C07C45/56—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds from heterocyclic compounds
- C07C45/562—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds from heterocyclic compounds with nitrogen as the only hetero atom
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/58—Preparation of carboxylic acid halides
- C07C51/60—Preparation of carboxylic acid halides by conversion of carboxylic acids or their anhydrides or esters, lactones, salts into halides with the same carboxylic acid part
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D295/00—Heterocyclic compounds containing polymethylene-imine rings with at least five ring members, 3-azabicyclo [3.2.2] nonane, piperazine, morpholine or thiomorpholine rings, having only hydrogen atoms directly attached to the ring carbon atoms
- C07D295/02—Heterocyclic compounds containing polymethylene-imine rings with at least five ring members, 3-azabicyclo [3.2.2] nonane, piperazine, morpholine or thiomorpholine rings, having only hydrogen atoms directly attached to the ring carbon atoms containing only hydrogen and carbon atoms in addition to the ring hetero elements
- C07D295/027—Heterocyclic compounds containing polymethylene-imine rings with at least five ring members, 3-azabicyclo [3.2.2] nonane, piperazine, morpholine or thiomorpholine rings, having only hydrogen atoms directly attached to the ring carbon atoms containing only hydrogen and carbon atoms in addition to the ring hetero elements containing only one hetero ring
- C07D295/03—Heterocyclic compounds containing polymethylene-imine rings with at least five ring members, 3-azabicyclo [3.2.2] nonane, piperazine, morpholine or thiomorpholine rings, having only hydrogen atoms directly attached to the ring carbon atoms containing only hydrogen and carbon atoms in addition to the ring hetero elements containing only one hetero ring with the ring nitrogen atoms directly attached to acyclic carbon atoms
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- 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
The invention relates to the technical field of dibenzoylmethane processing, and discloses a synthetic method of dibenzoylmethane, which comprises the following steps: step one, enamine preparation: reacting acetophenone with pyrrolidine under the catalysis of p-toluenesulfonic acid, and azeotropically dehydrating with toluene to obtain enamine; step two, preparing benzoyl chloride: reacting benzoic acid with thionyl chloride to generate benzoyl chloride; step three, preparation of dibenzoylmethane: the enamine and benzoyl chloride undergo nucleophilic addition-elimination reaction and acidic hydrolysis to obtain the target product. The method has the advantages of mild reaction conditions and less side reaction; the prepared DBM has higher overall yield and good product quality; in addition, the technical scheme produces less wastewater, does not produce wastewater of high-concentration acid and solvent which are difficult to treat, and does not produce wastewater of high-concentration salt and solvent which are difficult to treat, so that the subsequent wastewater treatment difficulty is greatly reduced.
Description
Technical Field
The invention relates to the technical field of dibenzoylmethane processing, in particular to a synthetic method of dibenzoylmethane.
Background
Dibenzoylmethane DBM for short, molecular formula is C 15 H 12 O 2 Is a compound having a diketone structure. Its most important use is as a light stabilizer for thermoplastics, is widely used in PVC plastics and ABS resins. The dibenzoylmethane has the characteristics of no toxicity and no smell, conforms to the environmental trend, and has an increasingly important position in the field of light stabilizers. With the continuous development of dibenzoylmethane functions, the demand for dibenzoylmethane is increasing at home and abroad, and especially the demand for dibenzoylmethane with high content and good color is larger.
Although the synthesis method of dibenzoylmethane has been reported, the method suitable for large-scale industrialized production is not more, and the problems of low color difference, low content, high production cost and the like of products are common. The synthesis process of dibenzoylmethane in the prior art mainly comprises the following steps: 1. the method comprises the steps of reacting acetophenone, benzyl chloride and sodium hydride in a solvent to obtain 1, 3-diphenyl-acetone, oxidizing the 1, 3-diphenyl-acetone under the catalysis of tert-butyl nitrite and N-hydroxysuccinimide to obtain a crude dibenzoylmethane product, and recrystallizing the crude dibenzoylmethane product by using methanol or ethanol as a recrystallization solvent to obtain a refined dibenzoylmethane product. 2. Benzoic acid and a large excess of methanol are used as raw materials, sulfuric acid is used as a catalyst to prepare methyl benzoate, the methyl benzoate generates DBM sodium salt under the catalysis of sodium methoxide, and the DBM sodium salt is acidolyzed by sulfuric acid to obtain dibenzoylmethane. The method has the following problems: 1. the sodium hydride is used as a catalyst to generate hydrogen, the explosion limit of the hydrogen is 4 to 75.6 percent, and the hydrogen has great danger; 2. the catalyst tert-butyl nitrite (1.1 equivalent) and N-hydroxysuccinimide (0.2 equivalent) are used in large amounts and have no recycling scheme, so that the raw material cost is high and a large amount of generated waste liquid is not easy to treat. The second method has the following problems: 1. the overall yield is not high and the color is not good; 2. the dosage of methanol is 4-10 times of the theoretical dosage in the esterification reaction, and the dosage of sulfuric acid is also larger, so that a large amount of wastewater containing methanol and sulfuric acid is generated; 3. the carboxyl of the benzoic acid is directly connected with the benzene ring, and the conjugation effect of the benzene ring causes lower electrophilicity of the carboxyl, so that the conversion rate of the benzoic acid is still low despite the large excessive methanol, and rectification and purification are needed; 4. the condensation and hydrolysis steps produce a large amount of sodium sulfate, and the wastewater contains a large amount of methanol, so that the wastewater is difficult to treat. Therefore, there is a need to develop a synthesis method of dibenzoylmethane with less side reactions, high overall yield and less wastewater generation.
Disclosure of Invention
The invention aims to provide a synthesis method of dibenzoyl methane, which solves the problems of more side reactions, low yield and difficult wastewater treatment in the prior art when dibenzoyl methane is produced.
In order to achieve the above purpose, the invention adopts the following technical scheme: a synthetic method of dibenzoylmethane comprises the following steps:
step one, enamine preparation: reacting acetophenone with pyrrolidine under the catalysis of p-toluenesulfonic acid, and azeotropically dehydrating with toluene to obtain enamine;
step two, preparing benzoyl chloride: reacting benzoic acid with thionyl chloride to generate benzoyl chloride;
step three, preparation of dibenzoylmethane: the enamine and benzoyl chloride undergo nucleophilic addition-elimination reaction and acidic hydrolysis to obtain the target product.
The principle and the advantages of the scheme are as follows: in practical application, dibenzoylmethane always has the problems of higher magazines, lower yield and more three wastes in the research and development preparation process. In the technical scheme, a brand new dibenzoyl methane synthesis process is developed through intensive research and development aiming at a plurality of problems existing in the dibenzoyl methane preparation process in the prior art. Firstly, acetophenone reacts with secondary amine to generate enamine, then the enamine is used as a nucleophilic reagent to carry out nucleophilic addition-elimination reaction on acyl chloride to complete acylation, and finally the acylated enamine is hydrolyzed through imide salt to obtain a target product DBM. The reaction mechanism of this reaction is shown below. In the project research and development process, the selection of the secondary amine is one of the difficulties of the technical scheme, and although more secondary amines have certain catalytic action, the defects of incomplete reaction and high cost exist. In addition, how to ensure the product yield and content of DBM in the research and development process is another research and development difficulty of the technical scheme, and research discovers that: the ratio of each raw material, the water content of the process and the water content of the raw material have great influence on the yield and purity of DBM, and strict control on each index is required to ensure the yield and quality of dibenzoylmethane products.
Step one:
step two:
step three:
the beneficial effects of this technical scheme lie in:
1. the technical scheme has mild reaction conditions and less side reactions;
2. the DBM prepared by the technical scheme has higher overall yield and better product quality;
3. the technical proposal has less waste water, does not generate waste water of high-concentration acid and solvent which are difficult to treat, and also generates waste water of high-concentration salt and solvent which are difficult to treat, thereby greatly reducing the subsequent waste water treatment difficulty;
4. the solvent of the technical scheme is easy to recycle and reuse, and complete closed loop can be realized.
Preferably, as a modification, in the first step, the molar ratio of acetophenone to tetrahydropyrrole is 1:2-1: 2.5.
in the technical scheme, the molar ratio of acetophenone to tetrahydropyrrole has a great influence on the reaction process, the incomplete reaction of acetophenone can be caused by insufficient quantity of tetrahydropyrrole, and the content of the final product can be low due to residual acetophenone. In addition, in the research and development process of the technical scheme, acetophenone is also tried to react with other secondary amines (morpholine and piperidine), but experiments prove that the morpholine and the piperidine can also catalyze the reaction, but the conversion rate of the acetophenone as a raw material is only about 70-80%. And finally, the residual acetophenone enters a finished product, so that the purity of the final finished product is less than 90 percent.
Preferably, as a modification, in the first step, the temperature of the catalytic reaction is 90-110 ℃, the reaction time is 4.5-7.5h, and reflux is maintained in the reaction process.
In the technical scheme, the raw materials cannot react completely due to the fact that the reaction temperature is too low and the reaction time is too short. Increasing the reaction temperature and extending the reaction time leads to increased energy consumption. In the reaction process, proper reflux is always kept, water is carried out by toluene and is removed through a water separator, and the toluene can be returned to a reaction bottle to realize recycling. Studies have shown that in the preparation of enamines, the water produced by the reaction needs to be removed, otherwise the reaction is incomplete, resulting in insufficient final cost.
Preferably, in a modification, in the first step, water washing, atmospheric distillation and vacuum distillation are performed after the reaction is completed.
In the technical scheme, after the reaction is finished, washing is carried out, and the lower water phase is separated; and then excessive tetrahydropyrrole is distilled off at normal pressure, and toluene is distilled off under reduced pressure, so that on one hand, the purity of a product can be ensured, and on the other hand, the recycling of the tetrahydropyrrole and the toluene can be realized.
Preferably, as a modification, in the second step, the molar ratio of the benzoic acid to the thionyl chloride is 1:2-1:3.
In the technical scheme, the molar ratio of the benzoic acid to the thionyl chloride has a great influence on the reaction process, and excessive benzoic acid can cause incomplete reaction of the benzoic acid, so that residual benzoic acid enters a final product to influence the product content. Too much thionyl chloride addition does not affect the reaction itself, but increases the cost. In addition, in the preparation of acid chlorides, thionyl chloride cannot contain water, otherwise incomplete reaction is caused, and the product content is affected.
Preferably, as a modification, in the second step, the reaction temperature is 60-70 ℃ and the reaction time is 1-3 h.
In the technical scheme, the reaction temperature is too low to cause incomplete conversion of raw materials, and the reaction temperature is too high to cause increase of sulfoxide chloride loss; the prolonged reaction time has no effect on the reaction, but can reduce the recovery rate of thionyl chloride and increase the energy consumption.
Preferably, in the second step, the reaction is completed and then subjected to atmospheric distillation and vacuum distillation.
In the technical scheme, excessive thionyl chloride is mainly removed by atmospheric distillation after the reaction is finished, and toluene as a solvent is mainly removed by vacuum distillation, so that on one hand, the purity of a product can be ensured, and on the other hand, the recycling of thionyl chloride and toluene can be realized.
Preferably, as a modification, in the third step, the molar ratio of enamine to benzoyl chloride is 1:1-1:1.05.
In the technical scheme, the molar ratio of the enamine to the benzoyl chloride has a great influence on the reaction process, the enamine and the benzoyl chloride can be completely converted in an equimolar ratio, and excessive addition of the enamine or the benzoyl chloride can cause residual benzoyl chloride or enamine. Residual benzoyl chloride or enamine is converted into benzoic acid or acetophenone after acidic hydrolysis, and the content of the final product is affected.
Preferably, as a modification, in the third step, the reaction temperature is 85-105 ℃ and the reaction time is 3-8h.
In the technical scheme, the reaction temperature is too low to cause incomplete reaction or the reaction time needs to be prolonged, and the temperature is too high to cause the loss of reaction raw materials and solvents; incomplete reaction can be caused by insufficient reaction time, and the waste of manpower and material resources can be caused by prolonged reaction time.
Preferably, as an improvement, in the third step, the target product is obtained after cooling, acidolysis and washing after the reaction is finished.
In the technical scheme, the purpose of acidolysis is to free the tetrahydropyrrole, the purpose of water washing is to wash away residual acid, and the purity of the product can be improved through acidolysis and water washing processes.
Drawings
Fig. 1 is a process flow diagram of example 1 of the present invention.
FIG. 2 is a liquid chromatogram of dibenzoylmethane of example 1 of the present invention.
Detailed Description
The following is a detailed description of embodiments, but embodiments of the invention are not limited thereto. The technical means used in the following embodiments are conventional means well known to those skilled in the art unless otherwise specified; the experimental methods used are all conventional methods; the materials, reagents, and the like used are all commercially available.
Example 1
As shown in fig. 1, a synthesis method of dibenzoylmethane comprises the following steps:
step one, enamine preparation: into a clean and dry 500ml reaction flask were charged 120.15g (1 mol) of acetophenone, 142.24g (2 mol) of tetrahydropyrrole, 4.9g (0.05 mol) of sulfuric acid, and 100g of toluene. The temperature is raised to 90-110 ℃ for reaction for 5 hours. The proper reflux is kept all the time in the reaction process, water is carried out by toluene and is removed by a water separator, and the toluene is returned to the reaction bottle. After the reaction, 100g of tap water was added, and the mixture was stirred for 5 minutes and allowed to stand for 5 minutes, followed by separation of the lower aqueous phase. Excess tetrahydropyrrole is slowly distilled off under normal pressure (75-90 ℃), and toluene is distilled off under reduced pressure (70-100 ℃). After evaporation, the temperature is reduced to room temperature, 169g of white liquid enamine is obtained, and the yield is 97.54%.
Step two, preparing benzoyl chloride: 200g of toluene was added to a clean and dry 500ml reaction flask, 61.06g (0.5 mol) of solid formic acid was added while stirring, and 119g (1 mol) of thionyl chloride was added dropwise after the temperature in the reaction vessel was raised to 50 to 60 ℃. The temperature in the reaction bottle is kept at 60-70 ℃ in the dropping process, and the gas generated by the reaction is absorbed by water, so that the dropping is completed in about 2 hours. After the dripping, the reaction is carried out for 1h under the heat preservation. After the reaction is completed, excess thionyl chloride (65-85 ℃) is slowly distilled off under normal pressure, and then toluene solvent is distilled off under reduced pressure (70-100 ℃). After evaporation, cooling to room temperature, 70g of white viscous liquid benzoyl chloride is obtained, and the yield is 99.59%.
Step three, preparing DBM: 140.57g (1 mol) of benzoyl chloride prepared in the second step and 173.26g (1 mol) of enamine prepared in the first step are added into a clean and dry 500ml reaction bottle. Then heating to 95 ℃ and preserving heat for reaction for 5 hours. After the reaction, the temperature is reduced to 50 ℃ and 120g of 30% aqueous hydrochloric acid solution is added for acidolysis for 30min. After acidolysis, separating the water layer. The organic layer was washed with 100g of 5% sodium carbonate solution and 100g of tap water, respectively, to obtain 222.3g of a white viscous liquid DBM, with a yield of 99.13%.
Example 2 (2 times the amount of raw materials added in example 2)
A synthetic method of dibenzoylmethane comprises the following steps:
step one, enamine preparation: into a clean and dry 1000ml reaction flask were charged 240.3g (2 mol) of acetophenone, 284.48g (4 mol) of tetrahydropyrrole, 9.8g (0.1 mol) of sulfuric acid, and 200g of toluene. The temperature is raised to 90-110 ℃ for reaction for 5 hours. The proper reflux is kept all the time in the reaction process, water is carried out by toluene and is removed by a water separator, and the toluene is returned to the reaction bottle. After the reaction, 100g of tap water was added, and the mixture was stirred for 5 minutes and allowed to stand for 5 minutes, followed by separation of the lower aqueous phase. Excess tetrahydropyrrole is slowly distilled off under normal pressure (75-90 ℃), and toluene is distilled off under reduced pressure (70-100 ℃). After evaporation, the temperature is reduced to room temperature, and 339.5g of enamine serving as a white liquid is obtained, and the yield is 97.23%.
Step two, preparing benzoyl chloride: 400g of toluene was added to a clean and dry 1000ml reaction flask, 122.12g (1 mol) of solid formic acid was added while stirring, and 238g (2 mol) of thionyl chloride was added dropwise after the temperature in the reaction vessel was raised to 50 to 60 ℃. The temperature in the reaction bottle is kept at 60-70 ℃ in the dropping process, and the gas generated by the reaction is absorbed by water, so that the dropping is completed in about 2 hours. After the dripping, the reaction is carried out for 1h under the heat preservation. After the reaction is completed, excess thionyl chloride (65-85 ℃) is slowly distilled off under normal pressure, and then toluene solvent is distilled off under reduced pressure (70-100 ℃). After evaporation, cooling to room temperature, 139.5g of white viscous liquid benzoyl chloride is obtained, and the yield is 99.18%.
Step three, preparing DBM: to a clean and dry 1000ml reaction flask were added 281.14g (2 mol) of benzoyl chloride obtained in the second step and 346.52g (2 mol) of enamine obtained in the first step. Then heating to 95 ℃ and preserving heat for reaction for 5 hours. After the reaction, the temperature was lowered to 50℃and 240g of a 30% aqueous hydrochloric acid solution was added to carry out acidolysis for 30 minutes. After acidolysis, separating the water layer. The organic layer was washed with 100g of 5% sodium carbonate solution and 100g of tap water, respectively, to obtain 443.5g of a white viscous liquid DBM, and the yield was 98.83%.
Examples 1-3 are examples of the present invention, comparative examples 1-10 are comparative examples of the present invention, and each example and comparative example differ only in the selection of a part of the raw materials and parameters, and are specifically shown in table 1. Wherein, the term maintaining reflux refers to whether proper reflux is maintained during the reaction of acetophenone with secondary amine.
TABLE 1
Experiment one: DBM product characterization
The DBM product prepared in example 1 was characterized by liquid chromatography, the chromatogram of which is shown in FIG. 2. The results show that the purity and the content of the dibenzoylmethane obtained by the invention can reach higher level.
Experiment II: DBM yield and content (purity)
The yield and content of DBM prepared in each of the above examples and comparative examples were determined, wherein the content determination method was liquid chromatography, and three repeated experiments were performed for each group, and the specific results are shown in Table 2.
TABLE 2
| DBM yield (%) | DBM content (%) | |
| Example 1 | 99.13 | 98.97 |
| Example 2 | 98.83 | 98.68 |
| Example 3 | 98.91 | 98.77 |
| Comparative example 1 | 67.54 | 78.49 |
| Comparative example 2 | 71.45 | 69.44 |
| Comparative example 3 | 49.25 | 51.23 |
| Comparative example 4 | 32.18 | 35.41 |
| Comparative example 5 | 92.58 | 91.67 |
| Comparative example 6 | 85.68 | 87.59 |
| Comparative example 7 | 52.35 | 49.54 |
| Comparative example 8 | 34.21 | 37.59 |
| Comparative example 9 | 32.47 | 29.42 |
| Comparative example 10 | 31.52 | 31.2 |
The experimental result of comparative example 1 shows that morpholine is used for replacing the tetrahydropyrrole, the yield and the content of the product are obviously reduced, and the reaction activity of morpholine is obviously lower than that of the tetrahydropyrrole; the experimental result of comparative example 2 shows that the piperidine is used for replacing the tetrahydropyrrole, the yield and the content of the product are obviously reduced, and the reaction activity of the piperidine is obviously lower than that of the tetrahydropyrrole; the experimental results of the comparative examples 3 and 4 show that the consumption of the tetrahydropyrrole is reduced, the yield and the content of the product are sharply reduced, and the fact that the insufficient amount of the tetrahydropyrrole can lead to the incapability of converting a large amount of acetophenone into enamine and further incapability of converting the acetophenone into the product is shown; the experimental result of comparative example 5 shows that the reaction can be more thoroughly carried out by keeping certain reflux; the experimental results of the comparative examples 6 and 7 show that the consumption of thionyl chloride is reduced, the yield and the content of the product are reduced to a certain extent, and the defect of insufficient thionyl chloride can cause that benzoic acid cannot be completely converted into benzoyl chloride and further cannot be converted into the product; the experimental result of comparative example 8 shows that the presence of moisture in thionyl chloride results in a great reduction in the yield and content of the product, since the reaction of thionyl chloride with water results in benzoic acid being unable to be converted into benzoyl chloride and further unable to be converted into the product; the experimental result of comparative example 9 shows that insufficient amount of enamine leads to significant decrease in product yield and content, because insufficient amount of enamine leads to incomplete reaction of benzoyl chloride; the experimental result of comparative example 9 shows that insufficient amount of benzoyl chloride results in significant decrease of product yield and content, because insufficient amount of benzamide results in incomplete reaction of enamine;
the following conclusions can be drawn from the above comparative experiments: (1) the reactivity of the tetrahydropyrrole is higher than that of morpholine and piperidine. (2) The amount of tetrahydropyridine is 2 times and more higher than acetophenone. (3) Maintaining reflux can increase the yield and content of the product. (4) The amount of thionyl chloride is 2 times and more than benzoic acid. (5) The water content of thionyl chloride can seriously affect the yield and content of the product. (5) Too high or too low a ratio of enamine to benzoyl chloride can affect the yield and content of the product.
The foregoing is merely exemplary of the present invention, and specific technical solutions and/or features that are well known in the art have not been described in detail herein. It should be noted that, for those skilled in the art, several variations and modifications can be made without departing from the technical solution of the present invention, and these should also be regarded as the protection scope of the present invention, which does not affect the effect of the implementation of the present invention and the practical applicability of the patent. The protection scope of the present application shall be subject to the content of the claims, and the description of the specific embodiments and the like in the specification can be used for explaining the content of the claims.
Claims (7)
1. The synthesis method of dibenzoylmethane is characterized by comprising the following steps:
step one, enamine preparation: reacting acetophenone and tetrahydropyrrole under the catalysis of p-toluenesulfonic acid, and azeotropically dehydrating with toluene to obtain enamine, wherein reflux is kept in the reaction process, and the molar ratio of acetophenone to tetrahydropyrrole is 1:2-1:2.5;
step two, preparing benzoyl chloride: reacting benzoic acid with thionyl chloride to generate benzoyl chloride, wherein the molar ratio of the benzoic acid to the thionyl chloride is 1:2-1:3, and the thionyl chloride does not contain water;
step three, preparation of dibenzoylmethane: the target product is obtained by nucleophilic addition-elimination reaction and acidic hydrolysis of enamine and benzoyl chloride, and the molar ratio of enamine to benzoyl chloride is 1:1-1:1.05.
2. The method for synthesizing dibenzoylmethane according to claim 1, characterized in that: in the first step, the temperature of the catalytic reaction is 90-110 ℃ and the reaction time is 4.5-7.5 h.
3. The method for synthesizing dibenzoylmethane according to claim 2, characterized in that: in the first step, after the reaction is completed, water washing, atmospheric distillation and reduced pressure distillation are performed.
4. A method of synthesizing dibenzoylmethane according to claim 3, characterized in that: in the second step, the reaction temperature is 60-70 ℃ and the reaction time is 1-3 h.
5. The method for synthesizing dibenzoylmethane according to claim 4, which is characterized in that: in the second step, atmospheric distillation and vacuum distillation are performed after the reaction is completed.
6. The method for synthesizing dibenzoylmethane according to claim 5, which is characterized in that: in the third step, the reaction temperature is 85-105 ℃ and the reaction time is 3-8h.
7. The method for synthesizing dibenzoylmethane according to claim 6, characterized in that: and step three, cooling, acidolysis and washing after the reaction is finished to obtain a target product.
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| CN110818543A (en) * | 2018-08-09 | 2020-02-21 | 山东瑞丰高分子材料股份有限公司燕崖分公司 | Novel method for efficiently synthesizing dibenzoyl methane |
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| CN102491890A (en) * | 2011-11-23 | 2012-06-13 | 山东瑞丰高分子材料股份有限公司 | Preparation method of dibenzoylmethane and application of dibenzoylmethane in molding processing of thermoplastic resin |
| CN110818543A (en) * | 2018-08-09 | 2020-02-21 | 山东瑞丰高分子材料股份有限公司燕崖分公司 | Novel method for efficiently synthesizing dibenzoyl methane |
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