Method for synthesizing 2, 6-naphthalene dicarboxylic acid
阅读说明：本技术 一种合成2,6-萘二甲酸的方法 (Method for synthesizing 2, 6-naphthalene dicarboxylic acid ) 是由 邵晶晶 邓兆敬 冷炳文 魏小林 于 2021-11-25 设计创作，主要内容包括：本发明提供了一种合成2,6-萘二甲酸的方法,其以卤代芳烃和3-甲基-3-丁烯-1-醇为原料,经过C-C偶联反应、环化脱水反应和液相氧化反应三步工艺制备所述2,6-NDA。该方法无需经过脱氢和异构化步骤,缩短了工艺流程,简化了反应工艺。反应路线中不产生难以分离的2,6位取代的萘的同分异构体,大大降低了后续的分离纯化难度,能耗低,因此该工艺路线具有较明显的选择性和效率性。本方法使用负载型的Pd催化剂,减少了有机膦配体的使用,降低了催化剂的成本,无污染,便于催化剂的回收和循环使用,且终产品2,6-NDA的总收率最高可达到70%以上,原料卤代芳烃可选择范围广,可进行大规模生产。(The invention provides a method for synthesizing 2, 6-naphthalene dicarboxylic acid, which takes halogenated aromatic hydrocarbon and 3-methyl-3-butene-1-ol as raw materials and prepares the 2,6-NDA through three processes of C-C coupling reaction, cyclodehydration reaction and liquid-phase oxidation reaction. The method does not need dehydrogenation and isomerization steps, shortens the process flow and simplifies the reaction process. The reaction route does not generate isomers of 2, 6-substituted naphthalene which is difficult to separate, thereby greatly reducing the subsequent separation and purification difficulty and having low energy consumption, so the process route has obvious selectivity and efficiency. The method uses the supported Pd catalyst, reduces the use of organic phosphine ligands, reduces the cost of the catalyst, has no pollution, is convenient for the recovery and the recycling of the catalyst, has the highest total yield of the final product 2,6-NDA up to more than 70 percent, has wide selective range of raw material halogenated aromatic hydrocarbon, and can carry out large-scale production.)
1. A method for synthesizing 2, 6-naphthalene dicarboxylic acid is provided, wherein halogenated aromatic hydrocarbon shown in formula I and 3-methyl-3-butene-1-alcohol are used as raw materials to prepare 2, 6-naphthalene dicarboxylic acid;
in the formula I, R1Is selected from-CH3、-CH2CH3、-COOH、-COOCH3、-COCH3；R2Selected from Cl or Br.
2. Method according to claim 1, characterized in that it comprises the following steps: halogenated aromatic hydrocarbon shown in a formula I and 3-methyl-3-butene-1-ol are taken as raw materials to perform C-C coupling reaction under the action of a Pd-based catalyst to obtain an intermediate product in the first step; under the action of a Pt-based catalyst or a modified Pt-based catalyst, the intermediate product in the first step is subjected to cyclodehydration reaction under the heating condition to obtain an intermediate product in the second step; the intermediate product in the second step undergoes liquid phase oxidation reaction under the action of a catalyst to finally generate 2, 6-naphthalene dicarboxylic acid (2, 6-NDA);
and/or the halogenated aromatic hydrocarbon shown in the formula I is p-chlorotoluene, p-chloroethylene, p-chlorobenzoic acid methyl ester, p-chloroacetophenone, p-bromotoluene, p-bromoethylbenzene, p-bromobenzoic acid methyl ester or p-bromoacetophenone.
3. The method according to claim 1 or 2, characterized in that the preparation method comprises the following steps:
step 1: halogenated aromatic hydrocarbon shown in a formula I and a compound shown in a formula II (3-methyl-3-butylene-1-alcohol) are subjected to C-C coupling reaction under the action of a Pt-based catalyst, an organic solvent, an auxiliary agent and alkali to generate an intermediate product shown in a formula I, an intermediate product shown in a formula I and/or an intermediate product shown in a formula II, and a reaction formula shown in the specification:
wherein R is1Is selected from-CH3、-CH2CH3、-COOH、-COOCH3、-COCH3；R2Selected from Cl or Br; the intermediate product I and the intermediate product II are isomers;
step 2: taking the intermediate product (i) and/or the intermediate product (ii) in the step (1) as a reaction substrate, and performing cyclodehydration reaction under the action of a Pt-based catalyst or a modified Pt-based catalyst and a solvent to generate an intermediate product shown in a formula (iii), which is marked as an intermediate product (iii), wherein the reaction formula is shown as follows:
and step 3: taking the intermediate product (c) in the step (2) as a reaction substrate, and introducing oxygen-containing gas to perform liquid phase oxidation reaction under the action of a catalyst and a solvent to generate a target product 2,6-NDA, wherein the reaction formula is as follows:
。
4. the method of claim 3, wherein the reaction conditions of step 1 are: in a reaction kettle with condensing reflux and stirring, raw materials of halogenated aromatic hydrocarbon and 3-methyl-3-butene-1-ol with the same equivalent weight are stirred and reacted for 0.5 to 6 hours in a nitrogen atmosphere under the action of an organic solvent, an auxiliary agent and alkali at the temperature of 90 to 150 ℃ and the pressure of 0 to 1.0MPa in a Pd-based catalyst;
and/or, the reaction conditions of the step 2 are as follows: in a fixed bed reactor with a gasification chamber, the temperature is 400-550 ℃, the pressure is 0.5-1.5 MPa, and the airspeed is 1.5-4.5 h-1Under the condition of carrier gas, the intermediate product (I) and/or the intermediate product (II) generates a cyclodehydration reaction under the action of a Pt-based catalyst or a modified Pt-based catalyst and a solvent;
and/or, the reaction conditions of the step 3 are as follows: in a reaction kettle equipped with condensation reflux and stirring, reacting the intermediate product (c) with oxygen-containing gas for 2-5 h at the temperature of 160-230 ℃ and the pressure of 1.0-3.0 MPa under the action of a solvent and a Co-Mn-Br catalyst.
5. The method as claimed in claim 3, wherein in step 1, the molar ratio of the halogenated aromatic hydrocarbon of formula I to the compound of formula II is (0.5-2): 1;
and/or the Pd-based catalyst is a supported Pd-based catalyst, and the carrier of the Pd-based catalyst is one or more of titanium dioxide, aluminum oxide, a Y molecular sieve and active carbon; the active component is Pd;
and/or the organic solvent is selected from one or more of N-methyl pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, ethyl acetate, toluene and 1, 4-dioxane;
and/or the molar ratio of the organic solvent to the halogenated aromatic hydrocarbon shown in the formula I is (0.5-5): 1;
and/or the auxiliary agent is selected from one or more of tetrabutylammonium bromide, tetrabutylammonium iodide and tetrabutylammonium chloride;
and/or the molar ratio of the auxiliary agent to the halogenated aromatic hydrocarbon shown in the formula I is (0.1-2): 1;
and/or the alkali is selected from one or more of potassium carbonate, cesium carbonate, sodium acetate and sodium ethoxide;
and/or the molar ratio of the alkali to the halogenated aromatic hydrocarbon shown in the formula I is (0.2-2): 1.
6. The method of claim 5, wherein the supported Pd-based catalyst of step 1 has an active component Pd content of 0.1-10 wt% based on the mass of the carrier;
and/or the addition amount of the Pd-based catalyst is 0.001-1 mol% of the halogenated aromatic hydrocarbon shown in the formula I based on the content of the active component Pd.
7. The method according to claim 3, wherein in step 2, the Pt-based catalyst is a supported Pt-based catalyst, and the modified Pt-based catalyst is a modified supported Pt-based catalyst;
and/or the solvent is selected from one or more of benzene, toluene, xylene, ethyl acetate and acetone;
and/or the mass ratio of the solvent to the reaction substrate in the step 2 is (4-19): 1;
and/or the reaction is carried out under the condition of a carrier gas, wherein the carrier gas is nitrogen, and the molar ratio of the flow rate of the carrier gas to the reaction substrate in the step 2 is (1-5): 1.
8. The method according to claim 7, wherein in the step 2, in the supported Pt-based catalyst or the modified supported Pt-based catalyst, the carrier is one or more of alumina, Y molecular sieve and activated carbon, the active component is Pt, and the modifier is an alkali metal carbonate.
9. The method according to claim 8, wherein, in step 2,
based on the mass of the carrier, the mass percentage content of the alkali metal carbonate is 0.1% -2.0%;
and/or the mass percentage content of the active component Pt is 0.005% -1% based on the mass of the carrier.
10. The method of claim 3, wherein in step 3, the solvent is a C1-C6 lower aliphatic carboxylic acid or a mixture thereof with water;
and/or the mass ratio of the solvent to the intermediate product (c) is (3-12): 1;
and/or, the oxygen-containing gas is air or oxygen;
and/or the catalyst is a Co-Mn-Br homogeneous catalyst which is a mixture of Co salt, Mn salt and Br salt.
11. The method of claim 10, wherein the Co salt is an acetate salt of Co; the Mn salt is Mn acetate; the Br salt is an alkali metal salt of Br;
in the Co-Mn-Br homogeneous catalyst, the molar ratio of Mn/Co is (0.5-2) to 1; the molar ratio of Br to Co is (0.5-4) to 1; the ratio of the total molar amount of Co + Mn to the molar amount of the intermediate product (c) is (0.1-0.3): 1.
12. A compound represented by formula (i) and/or a compound represented by formula (ii):
wherein R is1Having the definition set forth in claim 1.
Technical Field
The invention belongs to the technical field of compound synthesis, and particularly relates to a method for synthesizing 2, 6-naphthalene dicarboxylic acid.
Background
2, 6-naphthalenedicarboxylic acid (2, 6-NDA) is an important starting material for the production of polyethylene naphthalate (PEN). PEN is a new polyester product commercialized in the 90 s of the 20 th century, has better heat resistance, mechanical property, chemical property, mechanical property, gas barrier property and the like than polyethylene terephthalate (PET), is an excellent substitute of PET, and is called as a novel functional material of the 21 st century. In addition, 2,6-NDA is also an important monomer for synthesizing Liquid Crystal Polymer (LCP), the LCP synthesized by the monomer has more excellent heat resistance and processability, and has good applicability in the fields with higher requirements on use temperature and temperature difference change, such as automobiles, aerospace, jet engines and the like. The polyaramid prepared by 2,6-NDA partially replacing Terephthalic acid (PTA for short) has more outstanding heat resistance, and the prepared polyamide fiber has high strength. Meanwhile, 2,6-NDA is also an important intermediate of products such as electrons, pesticides, medicines, dyes, fluorescent whitening agents and the like. At present, because the production process of 2,6-NDA is complex and the production cost is high, the application of PEN, LCP and the like is limited to a certain extent, so that the development of a reasonable 2,6-NDA synthetic route and the reduction of the manufacturing cost of 2,6-NDA are the premise of large-scale production of PEN, LCP and the like.
The 2,6-NDA can be prepared mainly by Henkel method, carboxyl transfer method, dialkylnaphthalene oxidation method, beta-methylnaphthalene acylation oxidation method, etc. The focus of research at present is on the 2, 6-dimethylnaphthalene (2,6-DMN) oxidation method which has more significance in industrial development, and how to economically and effectively obtain 2,6-DMN is the problem to be solved firstly by the method. Methods for producing 2,6-DMN have been extensively studied before, but are still limited. The reports of the comprehensive literature show that the production methods of 2,6-DMN mainly comprise two methods: 1. naphthalene or alkyl naphthalene is used as a raw material; 2. benzene aromatic hydrocarbon is used as raw material.
In the patents of US6011190 and US6018086, monomethyl naphthalene and methanol are used as raw materials, and MCM-22 is used as an alkylation catalyst to prepare 2, 6-DMN. Although the raw material source of the route is wider, the conversion rate of the monomethyl naphthalene is only 58%, more isomers of DMN generated by the reaction are unavoidable, and the selection of a proper molecular sieve pore passage is difficult while maintaining ideal conversion rate and selectivity, so that the production cost of the 2,6-DMN is higher, and the difference from the industrial index is far.
The adoption of benzene-series aromatic hydrocarbon as a raw material is also a route which is researched more in recent years, and toluene or xylene is typically used as the raw material. BP Amoco is the first company for large-scale industrial production of 2,6-NDA worldwide. The production process of the company takes butadiene and o-xylene as raw materials, and the butadiene and the o-xylene are sequentially subjected to alkylation reaction, cyclization reaction, dehydrogenation reaction and isomerization reaction to obtain 2,6-DMN, and then subjected to liquid-phase oxidation reaction to produce 2,6-NDA (see patent documents U.S. Pat. No. 5,5334796, U.S. Pat. No. 4,825,5189234,5183933 and U.S. Pat. No. 5,5292934). However, in the production process, a plurality of DMN isomers are inevitably generated in the cyclization and isomerization steps, and pure 2,6-DMN can be produced only through an additional separation and purification step, so that the generation cost of 2,6-DMN is difficult to reduce, and the development of PEN and related polyester industries is restricted.
In recent years, a great deal of research and improvement has been made on the production process of 2,6-DMN at home and abroad. In patent CN111217659A, isoprene and methyl p-benzoquinone are used as raw materials, and under the action of heating and Lewis acid catalyst, an intermediate product, namely dimethyl hexahydronaphthalenone, is generated, and then under the action of Cu-based catalyst, dehydrogenation and deoxidation reactions occur, and finally 2,6-DMN is generated. In patent document CN104447179A, amyl alcohol and toluene are used as raw materials, and olefin is first obtained by dehydrogenation reaction, and 2,6-DMN is finally obtained after olefin and toluene are continuously subjected to alkylation, cyclodehydrogenation and isomerization reaction. In patent document CN111233602, 2,6-DMN is produced by using isoprene and 3-cyclohexene carbaldehyde as raw materials and performing a two-step reaction in the same manner. Although the above patent documents improve the synthesis method of 2,6-DMN and shorten the reaction steps, none of these synthetic routes can fundamentally avoid the formation of DMN isomers, especially 2,7-DMN, in the cyclodehydrogenation step. Since DMN isomers are very close in melting point, boiling point, solubility, etc. (e.g., melting point of 2,6-DMN is 263.3 deg.C, and melting point of 2,7-DMN is 262.8 deg.C), the purification cost of 2,6-DMN is high, thereby increasing the production cost of 2, 6-NDA. Therefore, it is important to develop a high-efficiency synthesis method without other isomers of 2, 6-DMN.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a high-efficiency and industrial production-worth 2,6-NDA synthesis method, which is used for overcoming the problems of long process route and low selectivity of an intermediate product, namely a 2, 6-substituted naphthalene compound in the prior art, and the invention is completed on the basis.
An object of the present invention is to provide a method for efficiently synthesizing 2, 6-NDA.
It is another object of the present invention to provide reaction conditions for the synthesis process.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a method for synthesizing 2, 6-naphthalene dicarboxylic acid is provided, wherein halogenated aromatic hydrocarbon shown in formula I and 3-methyl-3-butene-1-alcohol are used as raw materials to prepare 2, 6-naphthalene dicarboxylic acid;
in the formula I, R1Is selected from-CH3、-CH2CH3、-COOH、-COOCH3、-COCH3Etc.; r2Selected from Cl or Br.
According to the invention, the method comprises the following steps: halogenated aromatic hydrocarbon shown in a formula I and 3-methyl-3-butene-1-ol are taken as raw materials to perform C-C coupling reaction under the action of a Pd-based catalyst to obtain an intermediate product in the first step; under the action of a Pt-based catalyst or a modified Pt-based catalyst, the intermediate product in the first step is subjected to cyclodehydration reaction under the heating condition to obtain an intermediate product in the second step; the intermediate product in the second step is subjected to liquid phase oxidation reaction under the action of a catalyst (such as Co-Mn-Br catalyst, particularly Co-Mn-Br homogeneous catalyst) to finally generate 2, 6-naphthalenedicarboxylic acid (2, 6-NDA).
According to the invention, the halogenated aromatic hydrocarbon of formula I is, for example, p-chlorotoluene, p-chloroethylbenzene, p-chlorobenzoic acid methyl ester, p-chloroacetophenone, p-bromotoluene, p-bromoethylbenzene, p-bromobenzoic acid methyl ester or p-bromoacetophenone, etc.
According to the invention, the preparation method specifically comprises the following steps:
step 1: halogenated aromatic hydrocarbon shown in a formula I and a compound shown in a formula II (3-methyl-3-butylene-1-alcohol) are subjected to C-C coupling reaction under the action of a Pt-based catalyst, an organic solvent, an auxiliary agent and alkali to generate an intermediate product shown in a formula I, an intermediate product shown in a formula I and/or an intermediate product shown in a formula II, and a reaction formula shown in the specification:
wherein R is1Is selected from-CH3、-CH2CH3、-COOH、-COOCH3、-COCH3Etc.; r2Selected from Cl or Br; the intermediate product I and the intermediate product II are isomers;
step 2: taking the intermediate product (i) and/or the intermediate product (ii) in the step (1) as a reaction substrate, and performing cyclodehydration reaction under the action of a Pt-based catalyst or a modified Pt-based catalyst and a solvent to generate an intermediate product shown in a formula (iii), which is marked as an intermediate product (iii), wherein the reaction formula is shown as follows:
and step 3: taking the intermediate product (c) in the step (2) as a reaction substrate, and introducing oxygen-containing gas to perform liquid phase oxidation reaction under the action of a catalyst and a solvent to generate a target product 2,6-NDA, wherein the reaction formula is as follows:
。
according to the invention, the reaction conditions of the step 1 are as follows: in a reaction kettle with condensing reflux and stirring, raw materials of halogenated aromatic hydrocarbon and 3-methyl-3-butene-1-ol with the same equivalent weight are stirred and reacted for 0.5 to 6 hours in a nitrogen atmosphere under the action of an organic solvent, an auxiliary agent and alkali in a Pd-based catalyst at the temperature of 90 to 150 ℃ and the pressure of 0 to 1.0 MPa.
According to the invention, the reaction conditions of the step 2 are as follows: in a fixed bed reactor with a gasification chamber, the temperature is 400-550 ℃, the pressure is 0.5-1.5 MPa, and the airspeed is 1.5-4.5 h-1And under the condition of carrier gas, the intermediate product (I) and/or the intermediate product (II) generates cyclodehydration reaction under the action of Pt-based catalyst or modified Pt-based catalyst (specifically, Pt-based catalyst modified by alkali metal carbonate) and solvent.
According to the invention, the reaction conditions of step 3 are as follows: in a reaction kettle equipped with condensation reflux and stirring, reacting an intermediate product (III) with oxygen-containing gas for 2-5 h at the temperature of 160-230 ℃ and the pressure of 1.0-3.0 MPa under the action of a solvent and a Co-Mn-Br catalyst (especially a Co-Mn-Br homogeneous catalyst).
According to an embodiment of the present invention, in step 1, the halogenated aromatic hydrocarbon represented by formula I may be one or more selected from the group consisting of 4-chlorotoluene, 4-methyl chlorobenzoate, 4-chlorobenzoic acid, 4-chloroacetophenone and 4-bromotoluene.
According to an embodiment of the present invention, in step 1, the molar ratio of the halogenated aromatic hydrocarbon of formula I to the compound of formula II is (0.5-2): 1, preferably (0.8-1.2): 1, for example 1:1.
According to an embodiment of the present invention, in step 1, the Pd-based catalyst is a supported Pd-based catalyst, and the carrier of the supported Pd-based catalyst can be one or more of titanium dioxide, aluminum oxide, Y molecular sieve and activated carbon, such as Pd/Al2O3、Pd/C、Pd/TiO2Pd/Y molecular sieves, preferably Pd/Al2O3(ii) a The active component is Pd, and the precursor is one or more of palladium acetate, palladium nitrate, palladium chloride and palladium oxalate.
According to the embodiment of the invention, in the supported Pd-based catalyst in the step 1, the mass percentage of the active component Pd is 0.1-10%, preferably 0.2-1%, based on the mass of the carrier.
According to an embodiment of the present invention, in step 1, the amount of the Pd-based catalyst is 0.001mol% to 1mol%, preferably 0.01mol% to 0.5mol%, for example, 0.01mol%, 0.05 mol%, 0.1mol%, 0.5mol%, and more preferably 0.1mol% of the halogenated aromatic hydrocarbon represented by formula i, based on the content of the active component Pd.
According to an embodiment of the present invention, in step 1, the organic solvent is selected from one or more of N-methylpyrrolidone (NMP), N-Dimethylformamide (DMF), N-Dimethylacetamide (DMAC), ethyl acetate, toluene, 1, 4-dioxane, preferably N, N-dimethylacetamide.
According to an embodiment of the invention, in the step 1, the molar ratio of the organic solvent to the halogenated aromatic hydrocarbon shown in the formula I is (0.5-5): 1, preferably (1-5): 1.
According to an embodiment of the present invention, in step 1, the auxiliary agent is selected from one or more of tetrabutylammonium bromide, tetrabutylammonium iodide and tetrabutylammonium chloride.
According to an embodiment of the invention, in the step 1, the molar ratio of the auxiliary agent to the halogenated aromatic hydrocarbon shown in the formula I is (0.1-2): 1, preferably (0.2-0.6): 1.
According to an embodiment of the present invention, in step 1, the base is selected from one or more of potassium carbonate, cesium carbonate, sodium acetate and sodium ethoxide, preferably sodium acetate.
According to an embodiment of the present invention, in step 1, the molar ratio of the base to the halogenated aromatic hydrocarbon of formula I is (0.2-2): 1, preferably (0.5-1.5): 1.
According to an embodiment of the present invention, in step 1, the temperature of the reaction may be 100 to 180 ℃, for example 120 to 140 ℃, exemplary 100 ℃, 110 ℃, 120 ℃, 130 ℃, 140 ℃, 150 ℃, 160 ℃, 170 ℃ or 180 ℃.
According to an embodiment of the present invention, in step 1, the reaction time may be 20min to 300 min, for example, 60 min to 120min, and exemplary is 20min, 30 min, 60 min, 120min, 180 min, 240 min or 300 min.
According to an exemplary embodiment of the present invention, the step 1 may specifically include the following processes: adding halogenated aromatic hydrocarbon shown in a formula I, 3-methyl-3-butene-1-ol with the same equivalent weight, a Pd-based catalyst, an organic solvent, an auxiliary agent and alkali into a reaction kettle which is configured with condensation reflux and stirring, introducing nitrogen to replace air in the reaction kettle before the reaction starts, and stirring and reacting for 0.5-6 h under the conditions of 0-1.0 Mpa and 90-150 ℃; after the reaction is finished, the reaction mixture is in a solid-liquid two-phase state, and the solid-liquid phase separation is realized after centrifugal separation; adding 5 times of deionized water into the liquid phase product, simply extracting and separating, removing the organic solvent and the auxiliary agent, performing reduced pressure rectification to remove unreacted halogenated aromatic hydrocarbon and oligomer shown in the formula I to obtain a crude intermediate product I and/or an intermediate product II, performing qualitative analysis by a gas-mass spectrometer and a nuclear magnetic resonance spectrometer, and performing quantitative analysis by an external standard method of a gas chromatograph.
According to an embodiment of the present invention, in step 2, the Pt-based catalyst is a supported Pt-based catalyst, and the modified Pt-based catalyst is a modified supported Pt-based catalyst (for example, an alkali metal carbonate modified supported Pt-based catalyst).
According to the embodiment of the invention, in the supported Pt-based catalyst or the modified supported Pt-based catalyst, the carrier is one or more of aluminum oxide, Y molecular sieve and activated carbon, the active component is Pt, and the modifier is alkali carbonate.
According to the embodiment of the invention, the alkali metal carbonate is potassium carbonate or sodium carbonate, and the mass percentage of the alkali metal carbonate is 0.1-2.0% based on the mass of the carrier.
According to an embodiment of the present invention, the mass percentage content of the active component Pt is 0.005% to 1%, preferably 0.1% to 0.5%, based on the mass of the support.
For example, the supported Pt-based catalyst or the modified supported Pt-based catalyst is Pt/Al2O3Pt/C, Pt/Y molecular sieve, Pt-0.5% K/Al2O3、Pt-1%K/Al2O3、Pt-1.5%K/Al2O3Pt-0.5% K/C, Pt-1% K/C, Pt-1.5% K/C, Pt-0.5% K/Y molecular sieve, Pt-1% K/Y molecular sieve, Pt-1.5% K/Y molecular sieve, Pt-0.5% Na/Al2O3、Pt-1%Na/Al2O3、Pt-1.5%Na/Al2O3Pt-0.5% Na/C, Pt-1% Na/C, Pt-1.5% Na/C, Pt-0.5% Na/Y molecular sieve, Pt-1% Na/Y molecular sieve or Pt-1.5% Na/Y molecular sieve.
According to an embodiment of the present invention, in step 2, the solvent is selected from one or more of benzene, toluene, xylene, ethyl acetate and acetone, preferably toluene.
According to the embodiment of the invention, in the step 2, the mass ratio of the solvent to the reaction substrate in the step 2 is (4-19): 1, preferably (8-12): 1.
According to the embodiment of the invention, in the step 2, the reaction can be carried out in the presence of a carrier gas, wherein the carrier gas is nitrogen, and the molar ratio of the flow rate of the carrier gas to the reaction substrate in the step 2 is (1-5): 1.
According to an embodiment of the present invention, in step 2, the temperature of the reaction may be 400 to 550 ℃, for example 450 to 540 ℃, exemplary 400 ℃, 450 ℃, 470 ℃, 500 ℃, 520 ℃, 540 ℃ or 550 ℃.
According to an embodiment of the invention, in step 2, the pressure of the reaction may be 0.5 to 1.5MPa, such as 0.6 to 1.0MPa, exemplary 0.6MPa, 0.8MPa, 1.0 MPa.
According to an embodiment of the invention, in step 2, the reaction may be carried out in a reaction bed (e.g., a fixed bed reactor), and the substrate flow rate of the reaction may be 2 to 30 ml/h, e.g., 5 to 20 ml/h, illustratively 5 ml/h, 10 ml/h, 15 ml/h, 20 ml/h.
According to an exemplary embodiment of the present invention, the step 2 may specifically include the following processes: under the action of a advection pump, the intermediate product (I) and/or the intermediate product (II) enters a gasification chamber at 250 ℃ for gasification, and then enters a fixed bed reactor filled with a Pt-based catalyst or a modified Pt-based catalyst under the action of a carrier gas, and the pressure range and the volume airspeed of the intermediate product (I) and/or the intermediate product (II) are within the range of 0.5-1.5 MPa at the temperature of 400-550 ℃ and the volume airspeed of 0.5-4.5 h-1(e.g., 1.5 to 2.0 hours)-1) The reaction is carried out under the conditions of (1); after reacting for 2h, collecting the mixed solution of the products through a product tank at the lower end of the reaction tube, carrying out qualitative analysis through a gas-mass spectrometer and a nuclear magnetic resonance spectrometer, and carrying out quantitative analysis through a gas chromatograph external standard method.
According to an embodiment of the present invention, in step 3, the solvent is a C1 to C6 lower aliphatic carboxylic acid or a mixture thereof with water, illustratively formic acid, acetic acid or a mixture thereof with water.
According to an embodiment of the present invention, in step 3, the mass ratio of the solvent to the intermediate product (c) is (3-12): 1, preferably (5-10): 1, for example, 5:1, 7:1, 8:1, 10: 1.
According to an embodiment of the present invention, in step 3, the oxygen-containing gas is air or oxygen.
According to the embodiment of the invention, in the step 3, the catalyst is a Co-Mn-Br catalyst, specifically a Co-Mn-Br homogeneous catalyst, and the Co-Mn-Br homogeneous catalyst can be a mixture of Co salt, Mn salt and Br salt; the Co salt may be an acetate salt of Co, such as cobalt acetate or cobalt acetate tetrahydrate Co (CH)3COO)2·4H2O; the Mn salt may be an acetate salt of Mn, such as manganese acetate or manganese acetate tetrahydrate Mn (CH)3COO)2·4H2O; the Br salt may be an alkali metal salt of Br, for example KBr or NaBr.
According to an embodiment of the invention, the molar ratio of Mn/Co in the Co-Mn-Br homogeneous catalyst is (0.5 to 2:1, e.g. 0.5:1, 1:1, 2: 1; the molar ratio of Br/Co is (0.5-4) to 1, such as 0.8:1, 1:1, 1.5:1, 2.5: 1; the ratio of the total molar amount of (Co + Mn) to the molar amount of the intermediate product (c) is (0.1 to 0.3): 1, for example, 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.3:1, preferably 0.2: 1; the molar ratio of Co/Mn/Br is, for example, 1:1:0.8, 1:1:1, 1:1:1.5, 1:1:2.5, 1:0.5:1, 1:2:1, preferably 1:1: 1.5.
According to an embodiment of the present invention, in step 3, the temperature of the reaction may be 150 to 250 ℃, for example 180 to 230 ℃, exemplary 180 ℃, 200 ℃, 220 ℃, 230 ℃, 240 ℃, 250 ℃;
according to an embodiment of the invention, in step 3, the pressure of the reaction may be 1.0 to 3.0MPa, such as 1.8 to 2.6MPa, exemplary 1.8MPa, 2.0MPa, 2.2MPa, 2.3MPa, 2.4MPa, 2.6 MPa.
According to an embodiment of the invention, in step 3, the reaction time may be 2h to 8 h, for example 3 h to 5.5 h, exemplary 3 h, 4h, 4.5h, 5.5 h.
According to an embodiment of the present invention, the step 3 may specifically include the following processes: adding the intermediate product (c), acetic acid and Co-Mn-Br homogeneous catalyst into a 500ml reaction kettle with condensation reflux and stirring, replacing air in the kettle with nitrogen, boosting the pressure to 1.0MPa, keeping the pressure, starting stirring, raising the temperature to 100 ℃, introducing air to 1.0-3.0 MPa, continuously heating to 160-230 ℃, continuously introducing 2-8L/min of air, carrying out oxidation reaction for 2-5 hours, and stopping reaction. Releasing pressure and cooling to obtain a solid-liquid mixture, centrifugally separating, washing the obtained solid phase for 1 time by glacial acetic acid and 3 times by hot deionized water, and placing the solid phase in an oven for constant-temperature drying until the weight is constant, thus obtaining the crude product 2, 6-NDA. The purity of the product was determined by high performance liquid chromatography and the yield was calculated by weighing.
The invention also provides a compound shown as the formula (I) and/or a compound shown as the formula (II):
wherein R is1Having the definitions as described above.
Advantageous effects
1. Compared with the existing synthesis method, the novel process for preparing the 2,6-NDA by using the halogenated aromatic hydrocarbon shown in the formula I and the 3-methyl-3-butene-1-ol as raw materials through three steps of processes of C-C coupling reaction, cyclodehydration reaction and liquid-phase oxidation reaction does not need dehydrogenation and isomerization steps, shortens the process flow and simplifies the reaction process.
2. Compared with the existing synthesis method, the cyclization step of the three-step method for preparing the 2,6-DNA process does not generate 2, 6-substituted naphthalene isomer which is difficult to separate, thereby greatly reducing the subsequent separation and purification difficulty and having low energy consumption, so the process route has obvious selectivity and efficiency.
3. Compared with the traditional C-C coupling reaction, the supported Pd catalyst used in the reaction process in the step 1 of the process reduces the use of organic phosphine ligands, reduces the cost of the catalyst, has no pollution, and is convenient for the recovery and recycling of the catalyst.
4. The total yield of the 2,6-NDA in the process can reach more than 70 percent, and compared with the existing synthetic method, the process is simple to operate, and the yield of the 2,6-NDA is high.
5. The process has wide selective range of reaction raw materials of halogenated aromatic hydrocarbon and wide raw material source, and greatly reduces the limitation of the raw materials.
Drawings
FIG. 1 is a schematic representation of the alcohol and/or aldehyde intermediates prepared in example 11H NMR spectrum, solvent is deuterated DMSO.
FIG. 2 is a diagram of the cyclized intermediate prepared in example 31H NMR spectrum with solvent D2O。
Detailed Description
The technical solution of the present invention will be further described in detail with reference to specific embodiments. It is to be understood that the following examples are only illustrative and explanatory of the present invention and should not be construed as limiting the scope of the present invention. All the technologies realized based on the above-mentioned contents of the present invention are covered in the protection scope of the present invention.
Unless otherwise indicated, the raw materials and reagents used in the following examples are all commercially available products or can be prepared by known methods.
Example 1
100mmol of halogenated aromatic hydrocarbon, 100mmol of 3-methyl-3-buten-1-ol, 30 mmol of tetrabutylammonium bromide, 240 mmol of DMF and 100mmol of K2CO3And a Pd-based catalyst with a loading of 0.5wt% for different supports were added to a 250ml reaction vessel. After sealing, slowly replacing the air in the kettle with nitrogen for three times, starting stirring (600 rmp/min) and heating, raising the temperature in the reaction kettle to 150 ℃, keeping constant temperature, reacting for 120min, and stopping. Naturally cooling after the reaction is finished, separating a solid phase from a liquid phase by centrifuging a mixture after the reaction, qualitatively analyzing a product by a liquid phase substance through a nuclear magnetic resonance spectrometer and a gas-mass spectrometer, and quantitatively analyzing the reaction through a gas chromatograph to obtain the conversion rate of the raw material and the yield of the product; and adding deionized water into the solid mixture to dissolve soluble salts, continuing centrifugal separation, washing the solid matters obtained again with ethanol and water, and drying to obtain the recovered Pd-based catalyst. The reaction results are shown in table 1.
TABLE 1 influence of catalyst type, addition amount and halogenated aromatic hydrocarbon type on the reaction
Serial number
Catalyst and process for preparing same
Halogenated aromatic hydrocarbons
Catalyst addition amount (mmol)
Halogenated aromatic hydrocarbon conversion (%)
Intermediates (i) and (ii) Total yield (%)
1
Pd/Al2O3 4-chlorotoluene
0.1
83
58
2
Pd/C
4-chlorotoluene
0.1
56
43
3
Pd/TiO2 4-chlorotoluene
0.1
19
3
4
Pd/Y molecular sieve
4-chlorotoluene
0.1
21
14
5
Pd/Al2O3 4-Chlorobenzenecarboxylic acid methyl ester
0.1
92
16
6
Pd/Al2O3 4-Chlorobenzenecarboxylic acid
0.1
84
46
7
Pd/Al2O3 4-Chloroacetophenone
0.1
86
45
8
Pd/Al2O3 4-bromotoluene
0.1
99
59
9
Pd/Al2O3 4-chlorotoluene
0.01
36
28
10
Pd/Al2O3 4-chlorotoluene
0.05
62
47
11
Pd/Al2O3 4-chlorotoluene
0.5
86
35
The above results show that Al is used2O3Activated carbon, TiO2And a molecular sieve as a carrier to load an active Pd component, and can catalyze halogenated aromatic hydrocarbon and 3-methyl-3-butylene-1-alcohol in the table 1 to perform C-C coupling reaction under the conditions of self-boosting and 150 ℃ to generate an intermediate product (i) and/or (ii), wherein the catalyst adopts Pd/Al as a catalyst2O3Preferably, the halogenated aromatic hydrocarbons such as 4-chlorotoluene, 4-methyl chlorobenzoate, 4-chlorobenzoic acid, 4-chloroacetophenone, 4-bromotoluene and the like have wide applicability, and the catalyst has a good effect when the addition amount is 0.1 mol%.
From the aspects of production cost and applicability, 4-chlorotoluene is used as a raw material, the experimental product of the sequence No. 1 in the table is processed, liquid substances after reaction centrifugation are separated by column chromatography, and main intermediate products obtained after solvent is removed by rotary evaporation are subjected to hydrogen spectrum analysis of a nuclear magnetic resonance spectrometer, and the result is shown in figure 1. The nuclear magnetic resonance spectrometer shows that the main product is the structure of an intermediate product (namely 4- (p-tolyl) -3-methylbutyraldehyde), and the other extremely small amount of the intermediate product is determined to be the structure of an intermediate (namely) by a gas-mass spectrometer and is named as 4- (p-tolyl) -3-methyl-3-buten-1-ol.
Example 2
100mmol of 4-chlorotoluene, 100mmol of 3-methyl-3-buten-1-ol, 30 mmol of tetrabutylammonium bromide, 240 mmol of organic solvent, 100mmol of base and 0.5wt% of Pd/Al2O3The catalyst was added to a 250ml reaction kettle. After sealing, the air in the kettle was slowly replaced with nitrogen three times, the temperature in the reaction kettle was raised to the reaction temperature after stirring (600 rmp/min) and heating, the reaction was stopped after maintaining the constant temperature for a certain time, and the other operations were the same as in example 1. The reaction results are shown in Table 2
TABLE 2 influence of reaction temperature, time, organic solvent and kind of base on the reaction
Serial number
Reaction temperature (. degree.C.)
Reaction time (min)
Alkali
Organic solvent
Conversion of 4-chlorotoluene (%)
Intermediate products (i) and (ii) Total yield (%)
1
150
30
K2CO3 DMF
62
49
2
150
60
K2CO3 DMF
82
64
3
150
120
K2CO3 DMF
83
58
4
150
180
K2CO3 DMF
84
55
5
150
240
K2CO3 DMF
86
44
6
120
60
K2CO3 DMF
78
65
7
130
60
K2CO3 DMF
83
80
8
140
60
K2CO3 DMF
84
79
9
160
60
K2CO3 DMF
80
59
10
130
60
Cs2CO3 DMF
＞99
42
11
130
60
Sodium acetate
DMF
92
87
12
130
60
Sodium ethoxide
DMF
＞99
55
13
130
60
Sodium acetate
DMAC
96
93
14
130
60
Sodium acetate
NMP
91
84
15
130
60
Sodium acetate
Ethyl acetate
43
17
The above results show that with K2CO3，Cs2CO3Sodium acetate and sodium ethylate are used as alkaline auxiliary agents, DMF, DMAC, NMP and ethyl acetate are used as solvents, 4-chlorotoluene and 3-methyl-3-butene-1-ol can perform C-C coupling reaction under the reaction condition of self-pressure rise at the temperature of 120-160 ℃, and the total yield of the intermediate products (i) and (ii) is 17-93%. The reaction temperature is preferably within the range of 120-140 ℃, the reaction time is preferably within the range of 60-120min, the alkaline assistant is preferably sodium acetate, and the solvent is preferably DMAC.
Example 3
The crude product of experiment 13 from example 2 was usedAfter separation by simple extraction and rectification under reduced pressure, unreacted 4-chlorotoluene, solvent, auxiliary agent and oligomer are removed, and purified 4- (p-tolyl) -3-methylbutyraldehyde (containing a small amount of by-products of toluene and 4- (p-tolyl) -3-methyl-3-buten-1-ol) is mixed with solvent toluene to prepare a 10wt% mixed solution of 4- (p-tolyl) -3-methylbutyraldehyde. The reaction substrate was injected into a vaporizer using a flat flow, vaporized at 250 ℃ and then vaporized with 30ml/min of N2The product is brought into a fixed bed catalyst bed layer to react under the conditions of certain temperature, pressure and space velocity, the sample is taken for 2 hours of reaction, the conversion rate and the yield of the product are quantitatively calculated by gas chromatography, and the nuclear magnetic resonance hydrogen spectrogram of the purified product is shown in figure 2. The inner diameter of the fixed bed reactor is 10mm, the total length is 400mm, 1ml of different Pt-based catalysts are filled in the constant temperature section, and the catalyst is H at 0.5L/H before reaction2Reducing for 90min at 500 ℃ under air flow. The reaction results are shown in Table 3.
TABLE 3 reaction temperature, pressure and influence of catalyst on the reaction
The above results show that 4- (p-tolyl) -3-methylbutyraldehyde undergoes cyclodehydration at 450-540 ℃ under 0.6-1.0MPa to produce 2,6-DMN in 18.4-84.4% yield and Pt-1% K/Al2O3The catalyst is most preferred.
Example 4
Adding 2,6-DMN, solvent glacial acetic acid, catalyst cobalt acetate, manganese acetate and potassium bromide in a certain proportion into a 500ml Hastelloy reaction kettle. N is supplied to the reaction kettle by a nitrogen bottle through a pressure reducing valve2And replacing the air in the kettle, increasing the pressure to 1.0Mpa after replacement is finished, keeping the pressure, starting stirring, heating to 150 ℃, introducing the air, increasing the pressure to 2.4MPa, continuously heating to 230 ℃, continuously introducing 3L/min of air, carrying out oxidation reaction for 4 hours, and stopping the reaction. Cooling and releasing pressure to obtain solid-liquid mixture, centrifuging, washing the obtained solid phase with glacial acetic acid for 1 time and hot deionized water for 3 times, and drying in oven at constant temperature to constant weight to obtain the final productIs crude 2, 6-NDA. The purity of the product is analyzed by high performance liquid chromatography, and the reaction yield of the product is calculated by weighing. The results are shown in Table 4.
TABLE 4 influence of solvent and catalyst ratios on the reaction
Example 5
201g of glacial acetic acid (purity: 99.5%), 20.20g of 2,6-DMN (purity: 99%), 3.20g of Co (CH)3COO)2·4H2O (purity: 99.5%), 3.20g of Mn (CH)3COO)2·4H2O (purity: 98%) and 2.31g of KBr (purity: 99%) were charged into a 500ml Hastelloy reaction vessel, and the reaction temperature, pressure and reaction time were changed while keeping the charge ratio of the raw material, catalyst and solvent constant, and the other operations were the same as in example 4, and the results are shown in Table 5.
TABLE 5 Effect of reaction temperature, pressure and reaction time on the step 3 reaction
The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiment. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.