阅读说明：本技术 一种催化氧化制备2,5-二氯苯酚的钒吡啶/ts-1催化剂及其合成方法和应用 (Vanadium pyridine/TS-1 catalyst for preparing 2, 5-dichlorophenol through catalytic oxidation, and synthetic method and application thereof ) 是由 李舟 王文 罗君 唐昊 何路涛 于 2020-07-30 设计创作，主要内容包括：本发明公开了一种催化氧化制备2,5-二氯苯酚的钒吡啶/TS-1催化剂及其合成方法和应用,该催化剂为具有如下结构式所示的Py-V-TS-1化合物,它是通过4-羟基吡啶-2,6-二甲酸与乙酰丙酮氧钒反应制得Py-V-OH配合物、活化后的TS-1与(3-氯丙基)三甲氧基硅烷反应获得TS-1-<I>pr</I>-Cl中间体、TS-1-<I>pr</I>-Cl中间体与制得的Py-V-OH配合物进行偶联而获得。采用该Py-V-TS-1化合物作为催化剂,不但2,5-二氯苯酚的选择性达到90%以上,而且对副产物2,4-二氯苯酚的选择性可降至0.1%以下,同时过度氧化产物可控制在10%以下,氧化反应效率和收率均得到明显提高,催化效果较为理想。<Image he="272" wi="409" file="899670DEST_PATH_IMAGE002.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>(The invention discloses a vanadium pyridine/TS-1 catalyst for preparing 2, 5-dichlorophenol by catalytic oxidation, a synthesis method and application thereof, wherein the catalyst is a Py-V-TS-1 compound shown as the following structural formula, and is a Py-V-OH complex prepared by reacting 4-hydroxypyridine-2, 6-dicarboxylic acid with vanadyl acetylacetonate, and TS-1-one obtained by reacting activated TS-1 with (3-chloropropyl) trimethoxysilane pr -Cl intermediate, TS-1‑ pr Coupling the-Cl intermediate with the prepared Py-V-OH complex. By adopting the Py-V-TS-1 compound as a catalyst, the selectivity of 2, 5-dichlorophenol is over 90 percent, the selectivity of the byproduct 2, 4-dichlorophenol can be reduced to be below 0.1 percent, meanwhile, the over-oxidation product can be controlled to be below 10 percent, the oxidation reaction efficiency and yield are obviously improved, and the catalytic effect is ideal.)

1. A vanadium pyridine/TS-1 catalyst for preparing 2, 5-dichlorophenol by catalytic oxidation is characterized in that: is a Py-V-TS-1 compound shown as the following structural formula, and the compound is a light soil powder solid;

2. the synthesis method of the vanadium pyridine/TS-1 catalyst for preparing 2, 5-dichlorophenol by catalytic oxidation according to claim 1, characterized in that: the synthesis reaction formula is as follows:

the specific synthesis method comprises the following steps:

preparation of (mono) Py-V-OH complex

(1) Dissolving 4-hydroxypyridine-2, 6-dicarboxylic acid in 5-15 times of methanol by weight, and stirring at 50-70 ℃ until the solution is completely dissolved;

(2) adding 0.50 eq of vanadyl acetylacetonate into the mixed solution obtained in the step (1), and completely dissolving for 2-8 min to obtain a dark green clear solution;

(3) refluxing the clear solution obtained in the step (2) at 50-70 ℃ until a green solid is precipitated, continuously refluxing for 2-4 h, filtering, washing and drying to obtain a dark green powdery solid product, namely a Py-V-OH complex with a structural formula shown in the specification, wherein the yield is over 60 percent in terms of vanadium;

(II) TS-1-prPreparation of the-Cl intermediate

(1) Activating TS-1 at 120-180 ℃ for 2-6 h;

(2) placing the activated TS-1 in a container, adding dry toluene, adding (3-chloropropyl) trimethoxysilane and N under stirring₂Refluxing for 20-28 h at 100-125 ℃ under protection, cooling to less than 50 ℃, and filtering;

(3) drying the filter cake, sequentially carrying out Soxhlet extraction with toluene and dichloromethane for 12-18 h and 4-8 h, and drying the extracting solution at 60-100 ℃ to obtain an intermediate TS-1-pr-Cl；

Preparation of (tri) Py-V-TS-1 Compound

(1) The intermediate TS-1 obtained in the step (two)prplacing-Cl into a container, adding dry dimethyl formamide, stirring and cooling to 0 ℃, then slowly adding NaH, stirring at 0 ℃ for 10-30 min, and then heating to 10-15 ℃;

(2) adding the DMF solution of Py-V-OH prepared in the step (I) into a container, stirring and heating to 70-90 ℃, and preserving heat for 22-26 h;

(3) cooling the system to less than 50 ℃, then carrying out centrifugal separation, pulping and washing the obtained solid by using acetonitrile and dichloromethane in sequence, and then drying the solid under reduced pressure at the temperature of 30-50 ℃ to obtain a light soil toner powder solid product, namely a Py-V-TS-1 compound shown in the following structural formula;

3. the synthesis method of the vanadium pyridine/TS-1 catalyst for preparing 2, 5-dichlorophenol by catalytic oxidation according to claim 2, characterized in that: in the steps (one) - (1), the dissolving time of the 4-hydroxypyridine-2, 6-dicarboxylic acid in the methanol is 0.5-1.5 h.

4. The synthesis method of the vanadium pyridine/TS-1 catalyst for preparing 2, 5-dichlorophenol by catalytic oxidation according to claim 2, characterized in that: in the steps (one) - (3), the reflux reaction time is 0.5-1.5 h; washing the filtered green solid for 2-4 times by using methanol with the weight equal to that of 4-hydroxypyridine-2, 6-dicarboxylic acid; the drying temperature is 50-60 ℃.

5. The synthesis method of the vanadium pyridine/TS-1 catalyst for preparing 2, 5-dichlorophenol by catalytic oxidation according to claim 2, characterized in that: in steps (two) - (2), the water content of the dry toluene is less than 30 ppm; the addition amount of the dry toluene is 20-25 times of TS-1 by mass; the addition amount of the (3-chloropropyl) trimethoxy silane is 0.8-1.5 times of that of TS-1 by mass.

6. The synthesis method of the vanadium pyridine/TS-1 catalyst for preparing 2, 5-dichlorophenol by catalytic oxidation according to claim 2, characterized in that: in the steps (two) - (3), toluene and dichlorobenzene which are 10-15 times of the mass of the filter cake are respectively used for Soxhlet extraction according to the mass.

7. The synthesis method of the vanadium pyridine/TS-1 catalyst for preparing 2, 5-dichlorophenol by catalytic oxidation according to claim 2, characterized in that: in the step (three) - (1), the addition amount of the dimethylformamide is 10-15 times of the weight of the intermediate; the addition amount of the NaH is 2-3 times of the molar amount of the intermediate chlorine.

8. The synthesis method of the vanadium pyridine/TS-1 catalyst for preparing 2, 5-dichlorophenol by catalytic oxidation according to claim 2, characterized in that: in the steps (three) - (2), the DMF solution of Py-V-OH is a solution obtained by adding 0.03-0.05 g of Py-V-OH to each milliliter of DMF solvent, and the solution is added according to the equimolar amount of Py-V-OH and NaH.

9. The synthesis method of the vanadium pyridine/TS-1 catalyst for preparing 2, 5-dichlorophenol by catalytic oxidation according to claim 2, characterized in that: in the third step (3) and the third step (3), the amount of the acetonitrile is 20-50 times of the weight of the intermediate, and the intermediate is pulped and washed for 2-3 times; the dosage of the dichloromethane is 20-50 times of the weight of the intermediate, and the dichloromethane is beaten and washed for 2-3 times.

10. The use of the vanadium pyridine/TS-1 catalyst according to claim 1 in the catalytic oxidation of 2, 5-dichlorophenol, wherein: the method for preparing 2, 5-dichlorophenol by catalytic oxidation by taking a Py-V-TS-1 compound as a catalyst comprises the following steps:

(1) sequentially adding 1, 4-dichlorobenzene and 5-15 times of acetic acid by weight into a reaction container, and stirring for dissolving;

(2) adding 5 percent of Py-V-TS-1 compound catalyst of 1, 4-dichlorobenzene according to the weight ratio, and then dripping 0.3 eq of H with the mass concentration of 30 percent within 1-3H at the temperature of 60 DEG C₂O₂And after dripping, continuously preserving the temperature for 1 h to obtain a 2, 5-dichlorophenol product, sampling and carrying out HPLC detection to obtain a product with the conversion rate of 1, 4-dichlorobenzene being more than 15%, the selectivity of 2, 5-dichlorophenol being more than 90% and the selectivity of 2, 4-dichlorophenol being less than 0.1%.

Technical Field

The invention belongs to the technical field of preparation of 2, 5-dichlorophenol, and particularly relates to a vanadium pyridine/TS-1 catalyst for preparing 2, 5-dichlorophenol by catalytic oxidation of 1, 4-dichlorobenzene, a synthetic method and an application thereof.

Background

2, 5-dichlorophenol is an important intermediate of pesticide, medicine and dye, nitrogen fertilizer synergist, leather mildew preventive and the like, and is especially a main organic intermediate for preparing pesticide herbicide dicamba. In recent years, with the continuous improvement of greenhouse gas emission reduction and environmental protection requirements and the current situation that chlorsulfuron and metsulfuron-methyl preparations are forbidden and limited to use, the low-toxicity pesticide dicamba is widely applied to crop production, the demand is continuously increased, and the market prospect is good. Therefore, the research and development of the 2, 5-dichlorophenol intermediate have important function on developing dicamba which is a low-toxicity and high-efficiency herbicide.

The current process routes for preparing 2, 5-dichlorophenol mainly comprise the following two processes, namely 1,2, 4-trichlorobenzene hydrolysis and 2, 5-dichloroaniline diazo hydrolysis. As proposed in patent US2799714, 1,2, 4-trichlorobenzene is used as a raw material to prepare mixed dichlorophenol under an alkaline condition, and then 2, 5-dichlorophenol is obtained by separation; the process route is simple, but a large amount of acid and alkali can be used in the preparation process, a large amount of industrial three wastes are generated, and the industrial cost is high. 2, 5-dichlorophenol is prepared by diazotizing and hydrolyzing 2, 5-dichloroaniline as a raw material disclosed in the patent US 4326882; the process is a mature 2, 5-dichlorophenol synthesis process at present, and has the biggest defects of serious environmental pollution and serious corrosion to equipment due to the use of a large amount of inorganic acid and nitrite.

Aiming at the problems, the prior art also provides a method for preparing 2, 5-dichlorophenol by taking 1, 4-dichlorobenzene as a raw material through catalytic oxidation, heteropolyacid, copper porphyrin, iron oxide or a supported catalyst thereof is adopted, the reaction route is short, the operation is simple, and almost no pollution is caused to the environment. But the catalytic effect is not ideal and the product selectivity is low. For example, chinese patent CN107129426A discloses a method for preparing 2, 5-dichlorophenol, which is prepared by using 1, 4-dichlorobenzene as a raw material and one or more of water, methanol, acetonitrile and acetic acid as a solvent through catalytic oxidation under the action of an oxidant, a metalloporphyrin catalyst and a cocatalyst; the method achieves the purpose of improving the efficiency and the yield of the oxidation reaction by a catalytic system consisting of the metalloporphyrin catalyst and the cocatalyst, and the catalytic effect is still not ideal when the metalloporphyrin catalyst is used alone. Therefore, in the method for preparing 2, 5-dichlorophenol by catalytic oxidation of 1, 4-dichlorobenzene, the development of a catalyst with high efficiency, good selectivity and low by-product is necessary.

Disclosure of Invention

One of the purposes of the invention is to provide a vanadium pyridine/TS-1 catalyst for preparing 2, 5-dichlorophenol by catalytic oxidation, which is obtained by coupling 4-hydroxypyridine-2, 6-vanadyl dicarboxylate with a TS-1 titanium silicalite molecular sieve by adopting (3-chloropropyl) trimethoxysilane, and provides a beneficial reference value for preparing 2, 5-dichlorophenol by catalytic oxidation.

The second purpose of the invention is to provide a synthesis method of a vanadium pyridine/TS-1 catalyst for preparing 2, 5-dichlorophenol by catalytic oxidation, which comprises the steps of reacting 4-hydroxypyridine-2, 6-dicarboxylic acid with vanadyl acetylacetonate to prepare a Py-V-OH complex, and reacting the activated TS-1 with (3-chloropropyl) trimethoxysilane to obtain TS-1-pr-Cl intermediate, TS-1-prCoupling the-Cl intermediate and the prepared Py-V-OH complex to obtain the Py-V-TS-1 compound for preparing the 2, 5-dichlorophenol by catalytic oxidation, wherein the method has simple and easily controlled operation steps and is suitable for industrial production.

The invention also aims to provide an application of the vanadium pyridine/TS-1 catalyst in preparation of 2, 5-dichlorophenol by catalytic oxidation, in the process of preparing 2, 5-dichlorophenol by catalytic oxidation of 1, 4-dichlorobenzene, the Py-V-TS-1 compound is used as the catalyst, so that the over-oxidation of 2, 5-dichlorophenol can be effectively inhibited while the catalytic efficiency is improved, the over-oxidation product can be controlled to be below 10 percent, the selectivity of 2, 5-dichlorophenol can reach above 90 percent, and particularly the selectivity of the byproduct 2, 4-dichlorophenol can be reduced to below 0.1 percent.

The invention is realized by the following technical scheme: a vanadium pyridine/TS-1 catalyst for preparing 2, 5-dichlorophenol by catalytic oxidation is a Py-V-TS-1 compound shown in the following structural formula,

。

a vanadium pyridine/TS-1 catalyst for preparing 2, 5-dichlorophenol by catalytic oxidation is prepared by the following synthetic route:

wherein the synthetic reaction formula of Py-V-OH is as follows:

the specific synthesis method comprises the following steps:

preparation of (mono) Py-V-OH complex

(1) Dissolving 4-hydroxypyridine-2, 6-dicarboxylic acid in 5-15 times of methanol by weight, and stirring at 50-70 ℃ until the solution is completely dissolved;

(2) adding 0.50 eq of vanadyl acetylacetonate into the mixed solution obtained in the step (1), and completely dissolving for 2-8 min to obtain a dark green clear solution;

(3) and (3) carrying out reflux reaction on the clear solution obtained in the step (2) at 50-70 ℃ until a green solid is separated out, continuing refluxing for 2-4 h, and then filtering, washing and drying to obtain a dark green powdery solid product, namely a Py-V-OH complex shown in the following structural formula, wherein the yield is over 60 percent in terms of vanadium.

In the steps (one) - (1), the dissolving time of the 4-hydroxypyridine-2, 6-dicarboxylic acid in the methanol is 0.5-1.5 h.

In steps (one) - (2), the vanadyl acetylacetonate is added in an amount of 0.5 times by mole with respect to pyridine-2, 6-dicarboxylic acid.

In the steps (one) - (3), the reflux reaction time is 0.5-1.5 h.

In the steps (a) - (3), the green solid after filtration is washed with methanol of the same weight as 4-hydroxypyridine-2, 6-dicarboxylic acid in 2-4 times.

In the steps (one) - (3), the drying temperature is 50-60 ℃.

On the basis, the results of further qualitative and quantitative analysis are as follows:

the plasma emission spectrum ICP-AES of the Py-V-OH complex shown by the structural formula shows that: the vanadium mass fraction was found to be 9.65% (theoretical 11.81%), elemental analysis found C: 38.45 percent; h: 3.73 percent; n: 5.29% (theoretical C: 39.00%; H: 1.87%; N: 6.50%). According to the test result, three methanol molecules are also combined in the product molecule. I.e. the compound has the molecular formula C₁₄H₈N₂O₁₁V•3CH₃OH, molecular weight 527.29, and the compound was determined to be: 4-hydroxypyridine-2, 6-vanadyl dicarboxylate having the following structural formula:

(II) TS-1-prPreparation of the-Cl intermediate

(1) Activating TS-1 at 120-180 ℃ for 2-6 h;

(2) placing the activated TS-1 into a container, adding dry toluene, and adding (3-chloropropyl) trimethoxy silicon under stirringAlkane, N₂Refluxing for 20-28 h at 100-125 ℃ under protection, cooling to less than 50 ℃, and filtering;

(3) drying the filter cake, sequentially carrying out Soxhlet extraction with toluene and dichloromethane for 12-18 h and 4-8 h, respectively, and drying the solid obtained after Soxhlet extraction at 60-100 ℃ to obtain an intermediate TS-1-pr-Cl。

In steps (two) - (2), the water content of the dry toluene is less than 30 ppm; the addition amount of the dry toluene is 20-25 times of TS-1 by mass.

In the steps (two) - (2), the addition amount of the (3-chloropropyl) trimethoxy silane is 0.8-1.5 times of TS-1 by mass.

In the steps (two) - (3), toluene in an amount of 10-15 times and dichloromethane in an amount of 10-15 times by mass of the filter cake are respectively used for Soxhlet extraction.

Preparation of (tri) Py-V-TS-1 Compound

(1) The intermediate TS-1 obtained in the step (two)prplacing-Cl into a container, adding dry Dimethylformamide (DMF), stirring and cooling to 0 ℃, then slowly adding NaH, stirring at 0 ℃ for 10-30 min, and then heating to 10-15 ℃;

(2) adding the DMF solution of Py-V-OH prepared in the step (I) into a container, stirring and heating to 70-90 ℃, and preserving heat for 22-26 h;

(3) cooling the system to less than 50 ℃, then carrying out centrifugal separation, pulping and washing the obtained solid by using acetonitrile and dichloromethane in sequence, and then drying the solid under reduced pressure at the temperature of 30-50 ℃ to obtain a light soil toner powder solid product, namely a Py-V-TS-1 compound shown in the following structural formula;

。

in the step (three) - (1), the addition amount of the dimethylformamide is 10-15 times of the weight of the intermediate.

In the step (III) - (1), the addition amount of the NaH is 2-3 times of the molar amount of the intermediate chlorine.

In the steps (three) - (2), the DMF solution of Py-V-OH is a solution obtained by adding 0.03-0.05 g of Py-V-OH to each milliliter of DMF solvent, and the solution is added according to the equimolar amount of Py-V-OH and NaH.

In the third step (3) and the third step (3), the amount of the acetonitrile is 20-50 times of the weight of the intermediate, and the intermediate is pulped and washed for 2-3 times.

In the third step (3) and the third step (3), the amount of the dichloromethane is 20-50 times of the weight of the intermediate, and the intermediate is pulped and washed for 2-3 times.

The ICP-AES determined that the mass fraction of V in the solid was 1.71%, which was 0.33 mmol/g. According to the chlorine content of 0.40 mmol/g in the intermediate, Py-V-OH and TS-1-prThe reaction of-Cl produced Py-V-TS-1 with a vanadium content of 0.33 mmol/g in the product.

The application of the vanadium pyridine/TS-1 catalyst in the preparation of 2, 5-dichlorophenol by catalytic oxidation, which takes a Py-V-TS-1 compound as a catalyst, and the method for preparing the 2, 5-dichlorophenol by catalytic oxidation comprises the following steps:

(1) sequentially adding 1, 4-dichlorobenzene and 5-15 times of acetic acid by weight into a reaction container, and stirring for dissolving;

(2) adding 5 percent of Py-V-TS-1 compound catalyst of 1, 4-dichlorobenzene according to the weight ratio, and then dripping 0.3 eq of H with the mass concentration of 30 percent within 1-3H at the temperature of 60 DEG C₂O₂And after dripping, continuously preserving the temperature for 1 h to obtain a 2, 5-dichlorophenol product, sampling and carrying out HPLC detection to obtain a product with the conversion rate of 1, 4-dichlorobenzene being more than 15%, the selectivity of 2, 5-dichlorophenol being more than 90% and the selectivity of 2, 4-dichlorophenol being less than 0.1%.

In the step (2), the H₂O₂Is added in an amount of 0.3 times mole of 1, 4-dichlorobenzene.

The invention has the advantages and beneficial effects that:

1. the vanadium pyridine/TS-1 catalyst provided by the invention is obtained by coupling 4-hydroxypyridine-2, 6-vanadyl dicarboxylate with a TS-1 titanium silicalite molecular sieve by adopting (3-chloropropyl) trimethoxysilane, is a Py-V-TS-1 compound, has a definite structure, and has high selectivity on a product while improving the catalytic efficiency because a Py-V-OH complex structural formula contains carboxyl, and is proved in a process for preparing 2, 5-dichlorophenol by catalytic oxidation, so that the vanadium pyridine/TS-1 catalyst has high selectivity on the product while improving the catalytic efficiency, and can effectively inhibit the excessive oxidation of the 2, 5-dichlorophenol.

2. In order to further reduce the generation of the by-product 2, 4-dichlorophenol isomer, the invention discovers that when the TS-1 type titanium silicalite molecular sieve is used as a catalyst, the excessive oxidation of the product cannot be well inhibited, but the generation of the isomer 2, 4-dichlorophenol can be effectively avoided. Therefore, the 4-hydroxypyridine-2, 6-vanadyl dicarboxylate and the TS-1 titanium silicalite molecular sieve are coupled in a chemical mode to obtain the Py-V-TS-1 compound catalyst, so that the over-oxidation of a product can be effectively inhibited, the relative proportion of isomer 2, 4-dichlorophenol is very low, and the proportion of 2, 5-dichlorophenol and 2, 4-dichlorophenol is more than 1000/1.

3. The invention uses 4-hydroxypyridine-2, 6-dicarboxylic acid and vanadyl acetylacetonate to react to prepare Py-V-OH complex, and the activated TS-1 reacts with (3-chloropropyl) trimethoxysilane to obtain TS-1-pr-Cl intermediate, TS-1-prThe vanadium pyridine/TS-1 catalyst is obtained by coupling the-Cl intermediate and the prepared Py-V-OH complex and the like, the method has simple and easily controlled operation steps, the yield is over 60 percent in terms of vanadium, the time consumption of the whole synthesis process is short, and the method is suitable for industrial production.

4. The prior art shows that 1, 4-dichlorobenzene is used as a raw material to prepare 2, 5-dichlorophenol through catalytic oxidation, the reaction route is short, the operation is simple, and almost no pollution is caused to the environment, but heteropoly acid, copper porphyrin, iron oxide or a supported type heteropoly acid, copper porphyrin, iron oxide or supported type heteropoly acid, and the catalytic effect is not ideal. The 4-hydroxypyridine-2, 6-vanadyl phthalate is coupled with the TS-1 titanium silicalite molecular sieve in a chemical mode to obtain a Py-V-TS-1 compound, which is a novel catalyst for preparing 2, 5-dichlorophenol, in the process of preparing 2, 5-dichlorophenol by adopting one-step catalytic oxidation of 1, 4-dichlorobenzene, the selectivity of 2, 5-dichlorophenol is over 90 percent, the selectivity of the byproduct 2, 4-dichlorophenol can be reduced to be below 0.1 percent, meanwhile, the over-oxidation product can be controlled to be below 10 percent, the oxidation reaction efficiency and yield are obviously improved, and the catalytic effect is ideal.

Drawings

FIG. 1 is an HPLC chromatogram of the 2, 5-dichlorophenol product prepared in example 8 of the present invention.

Detailed Description

The present invention will be described in further detail with reference to examples. It should be noted, however, that the following examples are not to be construed as limiting the scope of the present invention, and that many insubstantial modifications and variations of the invention can be made by those skilled in the art without departing from the spirit and scope of the invention as set forth herein.