CN110801841A - Catalyst for preparing 2, 2' -bipyridine by coupling synthesis of pyridine and preparation method and application thereof - Google Patents

Abstract

The present invention provides a catalyst for synthesizing pyridine coupling to prepare 2,2'-bipyridine, a preparation method and application thereof. The catalyst uses nickel as the main active component, and is composed of silica and oxalic acid, nitric acid, sulfuric acid and hydrochloric acid. One or more modified macroporous aluminas are used as carriers, and nickel/alumina catalysts are prepared by conventional impregnation methods. During the impregnation process, L-arginine, cetyltrimethylammonium bromide (CTAB), polyvinylpyrrolidone (PVP), etc. were added to facilitate the dispersion of metals. By using the catalyst, the continuous reaction of pyridine coupling to prepare 2,2'-bipyridine in a fixed bed reactor can be realized.

Description

A kind of catalyst for synthesizing pyridine coupling to prepare 2,2'-bipyridine and preparation method thereof law and application

technical field

The invention belongs to the technical field of organic synthesis, and in particular relates to a catalyst for preparing 2,2'-bipyridine by pyridine coupling, a preparation method and application thereof.

Background technique

2,2'-bipyridine is an important fine chemical and pharmaceutical synthesis intermediate. At the same time, it is also a unique chelating agent, used as an indicator for detecting metal ions, a photosensitizer and a ligand for metal organic catalysts, etc. . Especially in recent years, with the banning of the highly toxic herbicide paraquat, the synthesis and production of the less toxic herbicide diquat will be put on an important agenda. The main raw material for diquat synthesis is 2,2'-bipyridine. Therefore, this product has important social significance and industrial application prospects for the development of downstream products of pyridine, especially the development and production of low-toxic pesticides.

At present, the domestic production process of 2,2'-bipyridine mainly uses pyridine as the raw material, which is first chlorinated and then coupled. Chinese patent CN103172559A reported a kind of synthesis of 2,2'-bipyridine with 2-chloropyridine as raw material and three-component catalyst of triphenylphosphine, zinc powder and nickel chloride. Although this process can obtain higher product yields, it is difficult to separate the catalyst from the product, it is inconvenient to recover and apply the catalyst, the steps are cumbersome, and the production cycle is long. The main problem is that the production process involves highly toxic chlorine gas. It also has huge corrosiveness to the equipment and causes serious pollution to the environment.

Chinese patent CN105461620A discloses a Raney nickel catalyzed preparation method of 2,2'-bipyridine. The method directly uses pyridine as a raw material and Raney nickel as a catalyst for pyridine coupling to prepare 2,2'-bipyridine. The method is clean and environmentally friendly, and the pyridine not involved in the reaction can be recycled. However, the preparation and use of Raney nickel catalysts have great safety problems. At the same time, the process adopts a tank reactor, which cannot realize continuous reaction and production like a fixed bed reactor.

Due to the development of reaction conditions and equipment, a device similar to the Soxhlet extractor has been produced. The progress of this method is to separate the 2,2'-bipyridine from the catalyst immediately after it is produced, so as to prolong the service life of the catalyst. At the same time, the product 2, The yield of 2'-bipyridine has also been improved to a certain extent, reaching 0.0231g 2,2'-bipyridine/g Raney nickel/hour (the following are simplified as g/g/h), while the original method The yield is only 0.007 g/g/h.

Gerald L. Goe proposed a method for the production of 2,2'-bipyridine in the 1990s. The method is still to use pyridine and Raney nickel catalyst, and control the reaction temperature between 200-240 °C (preferably at 220 °C in the experiment), because the reaction temperature is too high, the catalyst will fail quickly, and the temperature is too low. Yield drops. The pressure of the system may be controlled so as to keep a part of the pyridine in a liquid state.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a new catalyst for synthesizing 2,2'-bipyridine by coupling of pyridine, its preparation method and its application. Under the action of the catalyst, pyridine can be directly coupled by a continuous fixed bed process. Bi-2,2'-bipyridine does not need to be chlorinated first, and then dechlorinated and coupled with chloropyridine, which is environmentally friendly and does not require corrosion-resistant equipment.

The invention provides a catalyst for synthesizing pyridine coupling to prepare 2,2'-bipyridine. The catalyst uses nickel as the main active component, macroporous alumina as the carrier, and is prepared by impregnation method. The aluminum catalyst has a nickel content of 10-30%, preferably a nickel content of 15-25%, based on the weight percentage of the catalyst. Wherein, the alumina carrier is obtained after being modified by silica and one or more of oxalic acid, nitric acid, sulfuric acid and hydrochloric acid.

The impregnation method is to add surfactant in the process of impregnating nickel nitrate. The surfactant is one or more of L-arginine, cetyltrimethylammonium bromide and polyvinylpyrrolidone.

The invention provides the preparation method of the above-mentioned catalyst, and the concrete steps are as follows:

(1), pretreating the formed alumina carrier containing 0.1-5.0% by weight of silicon oxide, after being treated with 1-5% by weight of an acid solution at 80°C, then washing with water for 1-2 times, drying at 120°C, 400°C The modified alumina carrier is obtained by roasting at -800 DEG C for 3-5 hours; the acid solution is a mixture of one or more of oxalic acid, nitric acid, sulfuric acid and hydrochloric acid.

(2), the modified alumina carrier in step (1) was vacuumed for 1 hour;

(3), prepare nickel nitrate solution, and add surfactant in the solution, in terms of catalyst weight percentage, the nickel content is 15-30%, and the surfactant content is 1%-5% to obtain immersion liquid; It is one or more of L-arginine, cetyltrimethylammonium bromide (CTAB) and polyvinylpyrrolidone (PVP).

(4), suck the prepared impregnation solution into the modified alumina carrier treated by vacuum, age at 80°C for 1 hour, dry at 80°C for 4-8 hours, dry at 120°C for 6-12 hours, and dry at 300-600°C roasting for 3 hours;

(5), passing the product of step (4) into hydrogen and reducing at 200-550° C. for 2-10 hours to obtain a nickel/alumina catalyst.

The catalyst provided by the invention can realize the direct coupling of pyridine to produce 2,2'-bipyridine in a continuous fixed-bed reactor, and the catalyst exhibits high activity and stability. The coupling operation of chlorinating and dechlorinating pyridine first is not required.

The advantages of the invention are that: the alumina carrier after acid treatment and the active agent added in the preparation process can make the catalyst active component nickel highly dispersed, and has high activity in the reaction process of pyridine coupling to prepare 2,2'-bipyridine , good stability and so on. Under the action of this catalyst, pyridine can be directly coupled to 2,2'-bipyridine by a continuous fixed-bed process, without the need to chlorinate pyridine first, and then dechlorinate the pyridine for dechlorination coupling, which is green and environmentally friendly, and does not require resistance. Corroded equipment.

Detailed ways

The following examples will further illustrate the present invention, but do not limit the present invention accordingly.

Example 1

The spherical alumina carrier containing 3.0% silica is treated with about 3% of one or more solutions of oxalic acid, nitric acid, sulfuric acid and hydrochloric acid at 80°C, washed with water for 1-2 times, and dried at 120°C. The catalyst carrier was obtained by roasting at 650°C for 3 hours;

According to the content of nickel as the active component, nickel nitrate and polyvinylpyrrolidone were weighed and dissolved in water to prepare a solution. After the alumina carrier obtained by modification was evacuated, the impregnating liquid was sucked into the carrier by a conventional impregnation method, and then aged at 80°C. 2 hours, drying at 80°C for 6 hours, drying at 120°C for 12 hours, and calcining at 450°C for 3 hours; the calcined catalyst was introduced into hydrogen and reduced at 550°C for 5 hours.

The catalyst A prepared in this example contains 21% nickel, and 5% polyvinylpyrrolidone is added to the impregnation solution.

Example 2

Catalyst B was prepared in the same manner as in Example 1, except that the nickel content of the catalyst was 25%, and 2% of cetyltrimethylammonium bromide (CTAB) and 3% of polyvinylpyrrolidone (PVP) were added to the impregnation solution. ).

Example 3

Catalyst C was prepared in the same manner as in Example 1, except that the catalyst nickel content was 30%, and 5% polyvinylpyrrolidone (PVP) was added to the impregnation solution.

Example 4

Catalyst D was prepared in the same manner as in Example 1, except that the nickel content of the catalyst was 15%, and 3% L-arginine was added to the impregnation solution.

Comparative Example 1

Catalyst E was prepared in the same manner as in Example 1, except that the alumina carrier was not treated with one or more solutions in oxalic acid, nitric acid, sulfuric acid and hydrochloric acid, the catalyst nickel content was 21%, and no surface activity was added to the impregnation solution agent.

Example 5

The catalyst performance test was carried out in a self-made small-scale reaction device. The diameter of the reactor is 14mm, the catalyst loading is 2.5g, the reaction pressure is 1.0MPa, the reaction temperature is 200°C, and the pyridine mass space velocity is 8h ^-1 .

The product was analyzed by Varian 3800 chromatography, FID detector, HP-5 capillary column. The specific evaluation results are shown in Table 1.

Table 1 Catalyst evaluation results

catalyst Nickel content catalyst efficiency A twenty one% 0.378g 2,2'-bipyridine/g catalyst/h B 25% 0.362g 2,2'-bipyridine/g catalyst/h C 30% 0.258g 2,2'-bipyridine/g catalyst/h D 15% 0.357g 2,2'-bipyridine/g catalyst/h E twenty one% 0.078g 2,2'-bipyridine/g catalyst/h

Example 6

Under typical reaction conditions, the catalyst loading was 334Kg, and the catalyst A of the present invention was evaluated in a pilot scale for 330 hours in a continuous fixed-bed reactor. The results are shown in Table 2. According to the evaluation results, it is calculated that 40 tons of 2,2'-bipyridine can be produced per ton of catalyst.

Table 2 Catalyst A pilot test results of the present invention

Claims (10)

1. a catalyst for synthesizing pyridine coupling to make 2,2'-bipyridine, is characterized in that, this catalyzer takes nickel as main active component, the macroporous alumina of modified treatment is carrier, adopts impregnation method In the prepared nickel/alumina catalyst, the nickel content is 10-30% in terms of catalyst weight percentage. 2. The catalyst for preparing 2,2'-bipyridine by pyridine coupling according to claim 1, wherein the nickel content is 15-25% by weight of the catalyst. 3. a kind of catalyst for synthesizing pyridine coupling to produce 2,2'-bipyridine according to claim 1, is characterized in that, the modified alumina carrier is obtained through silica and oxalic acid, nitric acid, sulfuric acid and hydrochloric acid obtained after one or more modification treatments. 4. a kind of catalyst for synthesizing pyridine coupling to make 2,2'-bipyridine according to claim 1, is characterized in that: described impregnation method is to add surfactant in the process of impregnating nickel nitrate. 5. a kind of catalyst for synthesizing pyridine coupling to prepare 2,2'-bipyridine according to claim 4, is characterized in that: described surfactant is L-arginine, hexadecyl trimethyl One or more of ammonium bromide and polyvinylpyrrolidone. 6. a kind of preparation method of catalyst as described in any one of claim 1-5, is characterized in that, concrete steps are as follows: (1), pretreating the formed alumina carrier containing 0.1-5.0% by weight of silicon oxide, after being treated with 1-5% by weight of acid solution at 80°C, then washing with water for 1-2 times, drying at 120°C, 400°C -800 ℃ calcination for 3-5 hours to obtain modified alumina carrier; (2), the modified alumina carrier in step (1) was vacuumed for 1 hour; (3), prepare nickel nitrate solution, and add surfactant in solution, in catalyst weight percentage, nickel content is 15-30%, and surfactant content is 1%-5%, obtains immersion liquid; (4), suck the prepared impregnation solution into the modified alumina carrier treated by vacuum, age at 80°C for 1 hour, dry at 80°C for 4-8 hours, dry at 120°C for 6-12 hours, and dry at 300-600°C roasting for 3 hours; (5), passing the product of step (4) into hydrogen and reducing at 200-550° C. for 2-10 hours to obtain a nickel/alumina catalyst. 7 . The preparation method of a catalyst according to claim 6 , wherein the acid solution is a mixture of one or more of oxalic acid, nitric acid, sulfuric acid and hydrochloric acid. 8 . 8. the preparation method of catalyst according to claim 6 is characterized in that: surfactant is in L-arginine, cetyl trimethyl ammonium bromide (CTAB), polyvinyl pyrrolidone (PVP) one or more. 9. An application of the catalyst according to any one of claims 1-5, wherein the catalyst is used in a continuous fixed-bed reactor to realize direct coupling of pyridine to produce 2,2'-bipyridine, and the catalyst exhibits higher activity and stability. 10 . The application of the catalyst according to claim 9 , wherein the coupling operation of chlorination and dechlorination of pyridine is unnecessary. 11 .