CN106699571A - Preparation method of 2, 5-dichloroaniline - Google Patents

Abstract

The invention provides a method for preparing 2,5-dichloroaniline, which belongs to the field of compound production. Under the action of an oxidant, an aminating agent, a metal complex catalyst and a cocatalyst, 1,4-dichlorobenzene is used as a raw material, and one or more combinations of water, methanol, acetonitrile, acetic acid and ethanol are used as a solvent, The reaction temperature is 15-95° C., and the reaction time is 1-96 hours to obtain 2,5-dichloroaniline. The catalyst system used in the invention has high oxidative amination reaction efficiency and yield, relatively mild reaction conditions, few side reactions, easy separation of products, greatly shortened reaction time, and can be extended to large-scale industrial production.

Description

A kind of 2,5-dichloroaniline preparation method

technical field

The present invention relates to a method for preparing aromatic amines, in particular to a method for preparing 2,5-dichloroaniline by catalytic oxidative amination of 1,4-dichlorobenzene, which belongs to the field of compound production, especially pesticides , Manufacturing technology of pharmaceutical and dye intermediates.

Background technique

2,5-Dichloroaniline is a new type of anti-moth agent, which can be used to synthesize dye intermediates such as 2,5-dichloroaniline-4-sulfonic acid. It is an important intermediate of the agent N-2,5-dichlorophenylsuccinamic acid, the herbicide dicamba and the insecticide lufenuron.

The current preparation method of 2,5-dichloroaniline is mainly to obtain 2,5-dichloronitrobenzene by nitration of 1,4-dichlorobenzene first, and then reduce 2,5-dichloronitrobenzene with a reducing agent get. The research focus is mainly on the reduction step. The industrialized methods include iron powder reduction method, alkali sulfide reduction method and catalytic hydrogenation method. Among them, the iron powder reduction method and alkali sulfide reduction method have been basically eliminated due to the large amount of three wastes and heavy environmental pollution. , catalytic hydrogenation is the mainstream process.

Fan Guangyin from China West Normal University used titanium carbide-supported nano-metal as a catalyst in Chinese invention patent ZL2014103088955, and hydrogen was used as a reducing agent. The conversion rate of 2,5-dichloronitrobenzene was 100%, and 2,5-dichloroaniline The selectivity reaches 99%.

Yuan Yuan and others of Jiangsu Yangnong Chemical Co., Ltd. disclosed a production method of 2,5-dichloroaniline in Chinese invention patent 201310292296.4, using 2,5-dichloronitrobenzene as raw material, activated carbon supported palladium or Platinum is used as catalyst, ammonia water is used as auxiliary agent, hydrogen is used as reducing agent, the conversion rate of 2,5-dichloronitrobenzene and the selectivity of 2,5-dichloroaniline can reach 99%, and 2,5-dichloroaniline can be realized Automated continuous production of aniline.

People such as Meng Mingyang of Shenyang Institute of Chemical Industry reported in "Fine and Specialty Chemicals" in 2006, using their self-made catalyst, 2-n-butyl cyanoacrylate as anti-dechlorination agent, 2,5-dichloro Nitrobenzene is reduced to 2,5-dichloroaniline with hydrogen, and the product content is 99.3%, and the yield is 96.2%.

Report in U.S. Patent US4960936, adopt Raney-Ni (Raney nickel) as hydrogenation catalyst, formamidine acetate is auxiliary agent, in methanol, 2,5-dichloronitrobenzene is reduced to 2,5-dichloroaniline, The purity of the product 2,5-dichloroaniline after reduction can reach 99.6%.

Oliver Beswick reported in Catalysis Today 249 (2015) 45-51 that nano-iron oxide supported on activated carbon fiber was used as catalyst, and hydrazine hydrate was used as reducing agent to reduce 2,5-dichloronitrobenzene to 2,5 -Dichloroaniline, the selectivity is 100%, and the conversion rate of 2,5-dichloronitrobenzene reaches 95%.

In summary, the current preparation method of 2,5-dichloroaniline is to obtain 1,4-dichlorobenzene as raw material through two steps of nitration and reduction. A large amount of acid wastewater will be produced in the traditional nitrification process. In the reduction process, higher temperature and pressure are required to achieve the ideal yield, and the two-step reaction will increase the cost and reduce the economic benefit. For this reason, there is an urgent need for a method of using 1,4-dichlorobenzene as a raw material to directly introduce an amino group on the benzene ring to obtain 2,5-dichloroaniline through one-step oxidative amination. The direct introduction of amino groups on the aromatic ring is called aryl amination reaction. At present, the most researched is the direct aryl amination of benzene to generate aniline.

Zhang Yanhua of Hebei University of Technology and others disclosed a method for directly preparing aniline by reacting benzene with hydroxylamine salt in Chinese invention patents ZL201410751845.4 and ZL2014107514576, using vanadium dioxide or molybdenum dioxide supported on carbon materials as a catalyst, and the yields of aniline were respectively are 41% and 54%, and the selectivity is greater than 99%.

Hu Changwei of Sichuan University and others disclosed a method for preparing aniline by direct oxidative amination of benzene in Chinese invention patents ZL2013103606790 and ZL2010102185663, using benzene as raw material, ammonia water as amination agent, hydrogen peroxide as oxidant, water as solvent, and modified Silica-supported copper oxide or TS-1-supported metal is used as a catalyst to synthesize aniline in one step. The disadvantage is that the yield of aniline is only 6-10% and the selectivity is 60-85%.

Zhang Long and others from Changchun University of Technology provided a method for the direct amination of benzene to produce aniline in the Chinese invention patent CN2015101682055, using benzene as a raw material, V-MCM-41 as a catalyst, hydroxylamine as an aminating agent, and the selectivity of aniline is 100 %, the yield of aniline can reach 77.5%.

Lisitsyn, Yu A reported in Russian Journal of Physical Chemistry A, 86(6), 1033-1034; 2012 a method for the direct amination of anisole to generate methoxyaniline, which is an electrochemical method, using hydroxylamine as the amine Chemical agent, titanium tetrachloride as catalyst, water and acetic acid as solvent, the ratio of p-methoxyaniline and o-methoxyaniline is 66:34.

The aryl amination reaction of directly introducing amino groups on the benzene ring is an electrophilic reaction, and the presence of electron-withdrawing groups on the benzene ring is not conducive to the reaction. There are two chlorines on the benzene ring of 1,4-dichlorobenzene. Due to the strong electronic effect, it is difficult to carry out direct aromatic amination reaction to generate 2,5-dichloroaniline. No 1,4-dichloroaniline has been seen yet. A literature report on the direct arylation of benzene to 2,5-dichloroaniline.

Contents of the invention

The invention provides a new method for preparing 2,5-dichloroaniline by direct oxidative amination of 1,4-dichlorobenzene. The method uses 1,4-dichlorobenzene as a raw material, a metal complex as a catalyst, and a cocatalyst TS-1 molecular sieve and a quaternary ammonium salt to form a composite catalytic system, and oxygen, air, hydrogen peroxide or tert-butyl peroxidation Hydrogen is the oxidant, water, methanol, ethanol, acetonitrile or acetic acid is used as the solvent, ammonia water, ammonia gas, hydroxylamine hydrochloride, ammonium carbonate, ammonium bicarbonate or ammonium sulfate are used as the aminating agent, and the reaction is carried out at 15-95°C for 1-96h , after conventional separation, 2,5-dichloroaniline is obtained, and its yield ranges from 10-95%.

Compared with existing methods, the inventive method has the following advantages:

(1) This method uses 1,4-dichlorobenzene as a raw material, and the nitration-reduction two-step method of the original process is replaced by the oxidative amination one-step method, which can effectively reduce production costs and improve the economic benefits of the enterprise.

(2) Environmentally friendly oxygen, hydrogen peroxide, air or tert-butyl hydroperoxide are used as oxidants, and ammonia, hydroxylamine hydrochloride, ammonium carbonate, ammonium bicarbonate or ammonium sulfate are used as amination agents. The advantage is that the oxidizing agent has no harm to the environment, the price of the aminating agent is cheap, and the economy of reaction atoms is good, which is beneficial to industrial production.

(3) Using water, methanol, ethanol, acetonitrile or acetic acid as the reaction medium not only greatly reduces the production cost, reduces the corrosion of equipment, but also reduces the discharge of nitrification waste acid, which is in line with clean production and also improves safety in the production process.

(4) The reaction conditions of this method are relatively mild, the operation is simple and convenient, and the safety factor is high.

detailed description

Example 1

In a 100mL three-neck round bottom flask, add 14.7g 1,4-dichlorobenzene, 0.02g vanadyl acetylacetonate, 0.05g tetrabutylammonium bromide, 0.1g TS-1 molecular sieve, 15mL concentrated ammonia water, and 50mL acetonitrile 10.0 mL of 30% hydrogen peroxide was added dropwise into the reaction flask under stirring, and the reaction was continued at 90° C. for 5 h. After the reaction, the reaction liquid was cooled to room temperature, and the material was discharged, and analyzed by HPLC, the yield of 2,5-dichloroaniline was 57%, and the selectivity was 80%.

Example 2

The specific reaction process is the same as in Example 1, except that vanadyl acetylacetonate is replaced by molybdenum acetylacetonate, the yield of 2,5-dichloroaniline is 50%, and the selectivity is 92%.

Example 3

The specific reaction process is the same as in Example 1, except that vanadyl acetylacetonate is replaced by cobalt acetylacetonate, the yield of 2,5-dichloroaniline is 67%, and the selectivity is 85%.

Example 4

The specific reaction process is the same as in Example 1, except that vanadyl acetylacetonate is replaced by vanadyl phthalocyanine, the yield of 2,5-dichloroaniline is 75%, and the selectivity is 88%.

Example 5

The specific reaction process is the same as in Example 1, except that vanadyl acetylacetonate is replaced by cobalt phthalocyanine, the yield of 2,5-dichloroaniline is 68%, and the selectivity is 80%.

Example 6

The specific reaction process is the same as in Example 1, except that vanadyl acetylacetonate is replaced by molybdenum phthalocyanine, the yield of 2,5-dichloroaniline is 53%, and the selectivity is 72%.

Example 7

The specific reaction process is the same as that in Example 1, except that vanadyl acetylacetonate is replaced by cobalt porphine, the yield of 2,5-dichloroaniline is 55%, and the selectivity is 83%.

Example 8

The specific reaction process is the same as that of Example 1, except that vanadyl acetylacetonate is replaced by molybdenum porphine, the yield of 2,5-dichloroaniline is 42%, and the selectivity is 65%.

Example 9

The specific reaction process is the same as that of Example 1, except that vanadyl acetylacetonate is replaced with vanadyl porphin, the yield of 2,5-dichloroaniline is 79%, and the selectivity is 95%.

Example 10

The specific reaction process is the same as in Example 1, except that ammonia water is replaced with 13.8 g of hydroxylamine hydrochloride, the yield of 2,5-dichloroaniline is 38%, and the selectivity is 65%.

Example 11

The specific reaction process is the same as in Example 1, except that ammonia water is replaced by 13.2 g of ammonium sulfate, the yield of 2,5-dichloroaniline is 25%, and the selectivity is 38%.

Example 12

The specific reaction process is the same as in Example 1, except that ammonia water is replaced by 9.6 g of ammonium carbonate, the yield of 2,5-dichloroaniline is 22%, and the selectivity is 51%.

Example 13

The specific reaction process is the same as in Example 1, except that ammonia water is replaced by 13.8 g of ammonium bicarbonate, the yield of 2,5-dichloroaniline is 18%, and the selectivity is 45%.

Example 14

The specific reaction process is the same as in Example 1, except that the ammonia water is replaced by 68 g of ammonia gas, the yield of 2,5-dichloroaniline is 15%, and the selectivity is 83%. .

Example 15

The specific reaction process is the same as in Example 1, except that hydrogen peroxide is replaced by 10 mL of tert-butyl hydroperoxide, the yield of 2,5-dichloroaniline is 56%, and the selectivity is 96%.

Example 16

The specific reaction process is the same as in Example 1, except that hydrogen peroxide is replaced by 280 g of air, the yield of 2,5-dichloroaniline is 10%, and the selectivity is 98%.

Example 17

The specific reaction process is the same as in Example 1, except that hydrogen peroxide is replaced by 160 g of oxygen, the yield of 2,5-dichloroaniline is 13%, and the selectivity is 76%.

Example 18

The specific reaction process is the same as in Example 1, except that acetonitrile is replaced by acetic acid, the yield of 2,5-dichloroaniline is 45%, and the selectivity is 82%.

Example 19

The specific reaction process is the same as in Example 1, except that acetonitrile is replaced by methanol, the yield of 2,5-dichloroaniline is 33%, and the selectivity is 78%.

Example 20

The specific reaction process is the same as in Example 1, except that acetonitrile is replaced by ethanol, the yield of 2,5-dichloroaniline is 27%, and the selectivity is 80%.

Example 21

The specific reaction process is the same as in Example 1, except that acetonitrile is replaced by water, the yield of 2,5-dichloroaniline is 11%, and the selectivity is 93%.

Example 22

The specific reaction process is the same as in Example 1, except that tetrabutylammonium bromide is replaced by tetrabutylammonium chloride, the yield of 2,5-dichloroaniline is 20%, and the selectivity is 87%.

Example 23

The specific reaction process is the same as in Example 1, except that tetrabutylammonium bromide is replaced by tetraethylammonium chloride, the yield of 2,5-dichloroaniline is 18%, and the selectivity is 75%.

Example 24

The specific reaction process is the same as in Example 1, except that tetrabutylammonium bromide is replaced by tetraethylammonium bromide, the yield of 2,5-dichloroaniline is 15%, and the selectivity is 82%.

Example 25

The specific reaction process is the same as in Example 1, except that tetrabutylammonium bromide is replaced by triethylbenzylammonium chloride, the yield of 2,5-dichloroaniline is 35%, and the selectivity is 66%.

Example 26

The specific reaction process is the same as in Example 1, except that the reaction temperature is changed from 90°C to 30°C, the yield of 2,5-dichloroaniline is 36%, and the selectivity is 88%.

Example 27

The specific reaction process is the same as in Example 1, except that the reaction time is extended from 5 h to 48 h, the yield of 2,5-dichloroaniline is 68%, and the selectivity is 54%.

Example 28

The specific reaction process is the same as in Example 1, except that the amount of vanadyl acetylacetonate is changed to 0.2 g, the yield of 2,5-dichloroaniline is 78%, and the selectivity is 90%.

Although the invention has been described in detail with preferred embodiments, it is not intended to limit the invention. Those skilled in the art should be able to make various modifications and changes without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be regarded as the scope defined by the appended claims.

Claims (8)

1. A method for preparing 2,5-dichloroaniline, characterized in that, with 1,4-dichlorobenzene as starting raw material, metal complex as main catalyst, TS-1 molecular sieve and quaternary ammonium salt as promoter , under the combined action of an oxidizing agent, an aminating agent and a solvent, react at 15-95°C for 1-96h to prepare 2,5-dichloroaniline, and the yield ranges from 10-95%. 2. The method according to claim 1, wherein the metal complex is vanadyl acetylacetonate, molybdenum acetylacetonate, cobalt acetylacetonate, vanadyl phthalocyanine, molybdenum phthalocyanine, cobalt phthalocyanine, porphine cobalt, porphine One or more combinations of molybdenum and porphine vanadyl. 3. The method according to claim 1, wherein the quaternary ammonium salt is tetrabutylammonium bromide, tetrabutylammonium chloride, tetraethylammonium chloride, tetraethylammonium bromide and triethyl chloride One or more combinations of benzyl ammonium. 4. The method according to claim 1, characterized in that the oxidizing agent is one or more combinations of air, oxygen, hydrogen peroxide and tert-butyl hydroperoxide. 5. The method according to claim 1, wherein the aminating agent is one or more combinations of ammonia water, ammonia gas, hydroxylamine hydrochloride, ammonium sulfate, ammonium carbonate and ammonium bicarbonate. 6. The method according to claim 1, characterized in that the solvent is one or more combinations of water, acetonitrile, methanol, ethanol and acetic acid. 7. The method according to claim 1, characterized in that the molar ratios of oxidizing agent, aminating agent and solvent to 1,4-dichlorobenzene are 0.1～50, 0.2～50 and 0.5～100 (mass ratio) respectively. 8. The method according to claim 1, wherein the consumption of metal complex catalyst, quaternary ammonium salt and TS-1 molecular sieve is respectively 0.001～2%, 0.001～5% and 0.05% of 1,4-dichlorobenzene. ~10% (mass ratio).